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480 Cards in this Set
- Front
- Back
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what general type of parasite causes infection?
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endoparasite
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what general type of parasite causes infestation?
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ectoparastie
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an organism that MUST be a parasite
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obligate parasite
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an organism that does not have to be a parasite, but can (e.g. by accident)
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facultative parasite
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the host in which the parasite has reached sexual (reproductive) maturity
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definitive (final) host
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a host that serves a temporary but NECESSARY environment for the completion of immature stage(s) of the life cycle
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intermediate host
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host not needed to complete the life cycle but is utilized as a vehicle for reaching a necessary host
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paratenic (transport) host
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arthropods or other invertebrates which serve as hosts and carriers for parasites (may be intermediate or transport host)
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vector
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infected animal that serves as a source of infection for others
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reservoir host
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sylvatic reservoir
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wild animal reservoir host
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period required to reach reproductive maturity after infection of the definitive host with an animal or protist
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prepatent period
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period after infection before production of eggs/cysts, etc. in the definitive host
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prepatent period
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true or false:
the prepatent period is the period in the definitive host where a new generation is produced (adult to adult) |
false
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true or false:
the prepatent period may or may not present clinical signs |
true
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reproductively mature parasitic infection
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patent infection
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disease transmission from animals to humans
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zoonosis
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name the four major parasite phyla that we will be studying in this course
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Arthropoda, Protozoa (sarcomastigaphora, ciliaphora, apicomplexa), Platyhelminthes, Nematoda
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true or false:
parasitic infection does not necessarily constitute a disease |
true
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what age-group of animals is most susceptible to parasitic disease?
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young animals
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what are the two general factors in the susceptibility of an animal to parasitic infection and parasitic disease?
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1. environment (e.g. stress, hygeine)
2. heredity |
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the use of more than one method to control a parasitic infection
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integrated pest-parasite management
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name the three major classes in phylum Arthropoda relevant to this course
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Insecta, Arachnida, Crustacea
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Phylum and class of fleas
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Phylum Arthropoda
Class Insecta |
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Phylum and class of lice
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Phylum Arthropoda
Class Insecta |
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Phylum and class of flies
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Phylum Arthropoda
Class Insecta |
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Phylum and class of ticks
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Phylum Arthropoda
Class Arachnida |
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Phylum and class of mites
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Phylum Arthropoda
Class Arachnida |
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Phylum and class of isopods
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Phylum Arthropoda
Class Crustacea |
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Phylum and class of copepods
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Phylum Arthropoda
Class Crustacea |
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What are the three properties of a good pesticide?
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1. effective
2. safe 3. low cost |
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what are the three types of names assigned to any one drug or pesticide?
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Chemical name (long organic chemical name)
Generic name (the one on exams!) Trade name (brand name) |
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the length of time that a food animal or product must be withheld from entering the food chain following the treatment with a drug
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withdrawal period
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use of an approved drug in a manner that is not in accordance with the approved label instructions
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extra label use
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the three types of ARTHROPOD control agents
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1. pesticide (kill outright; interfere with normal growth and development)
2. biological control (e.g. hormones) 3. physical control (e.g. fly nets) |
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the two US Federal Government organizations that regulate pesticides
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EPA and FDA
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name the TEN arthropod pesticide groups that we are studying in this course
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1. pyrethrin/pyrethroid
2. macrolide 3. neonicotinid and spinosyns 4. semicarbazone 5. formamidamine 6. organophosphates and carbamates 7. insect growth regulators 8. insect development regulators 9. phenylpyrazole 10. organochlorines |
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a substance that prolongs the activity of a pesticide, but is not a pesticide itself
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synergist
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name two common synergists
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1. piperonyl butoxide
2. N-octylbicycloheptenedicarboximide |
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modes of action of pyrethrins/pyrethroids
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- disrupt ion transport in nerve membranes
- paralysis -repellant |
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pyrethrin/pyrethroid spectrum of action
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many species
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pyrethrin/pyrethroid general safety and signs of toxicity to animals
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- pretty safe
- salivation, diarhhea, vomiting, ataxia, convulsions, death |
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how old must a kitten/pup be before it can be given a pyrethrin/pyrethroid?
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at least 4 weeks of age
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name typical methods of pyrethrin/pyrethroid methods of application
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sprays, dusts, shampoos, spot-ons, environmental (e.g. misters; pyrethroids only)
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what are the major advantages of pyrethroids over pyrethrins?
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- more potent
- longer lasting |
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true or false:
pyrethrins and pyrethroids are condisered quick knockdown agents |
true
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true or false:
pyrethrins and pyrethroids are effective oral/injectible pesticides |
false
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true or false:
pyrethroids are generally less toxic than pyrethrins |
false (generally more toxic)
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true or false:
pyrethroids are toxic to fish |
true
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what type of pesticides have a generic name that ends in "thrin"?
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pyrethroids
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what are the two major types of macrolide pesticides?
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1. avermectins
2. milbemycins |
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true or false:
macrolides are not administered internally (e.g. oral, injectible) |
false - yes they are
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a pesticide that is effective against internal parasites
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endectocyde
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mode of action of macrolide pesticides
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binds to glutamate gated chloride channels leading to hyperpolarization of nerves and muscles
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where were macrolide pesticides discovered?
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fermentation products of soil microbes
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macrolide spectrum of action
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arthropods and worms
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persistence of macrolide pesticides
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can be weeks since they are lipophilic and stored in fat
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mode of administration of macrolide pesticides
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oral, spot-on, injection, feed additive
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what type of parasites do neonicotinids kill?
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insects
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neonicotinid spectrum of action
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fleas, lice, plant pests
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neonicotinid mode of action
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binds to postsynaptic nicotinic acetylcholine receptors in insects
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neonicotinoid toxicity to mammals
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low; mammals have different nicotinic receptors
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neonicotinoid persistence
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very short to weeks
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neonicotinoid methods of administration
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topical, oral
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what type of pesticide are the spinosyns?
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neonicotinoid
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spinosyn pesticide mode of action
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activates nicotinic acetylcholine receptors
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what type of pesticide is etofenprox?
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pyrethroid
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what type of pesticide is ivermectin?
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macrocyclic lactone
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what type of pesticide is selamectin?
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macrocyclic lactone
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what type of pesticide is doramectin?
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macrocyclic lactone
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what type of pesticide is eprinomectin?
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macrocyclic lactone
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what type of pesticide is milbemycin?
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macrocyclic lactone
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what type of pesticide is moxidectin?
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macrocyclic lactone
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name six generic names of macrocyclic lactones
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1. ivermectin
2. selamectin 3. doramectin 4. eprinomectin 5. milbemycin 6. moxidectin |
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what type of pesticide is imidicloprid?
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neonicotinoid
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what type of pesticide is nitrenpyram?
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neonicitinoid
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what type of pesticide is spinosad?
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spinosyn
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what type of pesticide is spinetoram?
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spinosyn
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what type of pesticide is amitraz?
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formamidine
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what type of pesticide is metaflumazone?
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semicarbazone
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what type of pesticide is lufenuron?
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insect development inhibitor
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what type of pesticide is methoprene?
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insect growth regulator
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what type of pesticide is pyriproxyfen?
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insect growth regulator
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what usually appears in the name of organophosphate based pesticides?
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phosphate, phor, phosphor
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what type of pesticides are lime sulfur and borax?
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inorganic
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what is the toxicity of spinosyns to animals?
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appears low
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what is the persistence of spinosyns?
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weeks (lipophilic)
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modes of administration of spinosyns
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oral (dogs), topical (cats), also used in plants
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what is the spectrum of action of phenylpyrazoles?
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insects, ticks, mites
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the mode of action of phenylpyrazoles
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binds to GABA receptors and inhibits the flux of ions into nerve cells: results in hyperexcitability and death
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toxicity of phenylpyrazoles
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generally safe
DON'T USE IN RABBITS toxic to fish and aquatics |
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persistence of phenylpyrazoles
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long: lipophilic and stored in hair follicles and sebaceous glands. Gradually released onto skin
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administration of phenylpyrazoles
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topical
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formamidines spectrum of action
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ticks and mites
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formamidine mode of action
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MAOI
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toxicity of formamidines
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relatively safe
DO NOT USE IN HORSES |
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method of administration of formamidies
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topical
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clinical signs of formamidine toxicity
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lethargy, hypotension, mydriasis (dilation of the pupil), hypothermia, vomiting
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formamidine persistence
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days
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what pesticide(s) should never be given to horses?
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formamidines
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what pesticide(s) should never be given to cats?
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permethrin
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what pesticide(s) should never be given to rabbits?
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phenylpyrazoles
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what pesticide(s) were pointed out as being especially toxic to aquatic organisms
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pyrethroids and phenylpyrazoles
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semicarbazone spectrum of action
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insects
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semicarbazone mode of action
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blocks sodium channels in axons and prevents neurotransmission
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toxicity of semicarbazones
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low because the mammalian receptor is different
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persistence of semicarbazones
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weeks - distrubuted in hair coats
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semicarbazone method of administration
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topical (combined with amitraz in dogs, but not cats)
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organophosphate spectrum of action
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many arthropods
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organophosphate mode of action
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- acetylcholinesterase inhibitor. persistent stimulation at the synapse
- acetocholine neurotransmitter in both vertebrates and invertebrates |
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organophosphate toxicity to mammals
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highly toxic
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signs of organophosphate toxicity in mammals
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salivation, lacrimation, urination, diarrhea, respiratory failure, chronic neurotoxicity, generally unpleasant disposition
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persistence of organophosphate pesticides
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newer ones can last for weeks
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organophosphate pesticide mode of administration
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topically (e.g. flea collars), environmental (especially for livestock)
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carbamate pesticide spectrum of action
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many arthropods
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carbamate mode of action
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Acetylcholinesterase inhibitor (persistent stimulation at the synapse)
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carbamate toxicity
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not as bad as organophosphates, but still toxic
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organochlorine pesticide mode of action
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inhibit sodium and calcium ion flux, which interferes with membrane (de)polarization
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what type of pesticide is DDT?
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organochlorine
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name five organochlorine pesticides
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DDT, lindane, dieldrin, aldrin, methoxychlor
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what is the major way in which insect development inhibitors work?
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prevent chitin synthesis
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what is the major way in which insect growth regulators work?
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insect juvenile hormone analogs and prevent maturation
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name two methods of biological pest control
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1. pheromones in traps
2. parasitic wasps |
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the development of an ability in a strain of some organism to tolerate doses of a toxicant that would prove lethal to a majority of individuals in a normal population of the same species
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resistance
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name four major methods of pesticide resistance
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1. target-site resistance
2. metabolic resistance 3. penetration resistance 4. behavioral resistance |
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what is target-site pesticide resistance?
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genetic difference in the molecular target of the drug (e.g. it doesn't bind to a mutated receptor)
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what is metabolic pesticide resistance?
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increased inactivation or removal of the drug from the parasite's system
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what is penetration pesticide resistance?
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slower absorption of the drug by the parasite
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what is behavioral pesticide resistance?
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avoidance of a pesticide
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explain the genetic basis of pesticide resistance
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a heritable random mutation in which that locus confers a reproductive advantage (e.g. due to lower lethality) to those without the mutation
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portion of a parasite population not exposed to a drug
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refugia
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how does the number of refugia in a parasite population affect the population's development of resistance to a pesticide?
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more refugia lowers the probablility of selection of resistant parasites and thus lowers the rate of selection for resistance.
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name four important factors that determine how fast a population of parasites will develop resistance to a drug
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1. dose - heterozygotes may be less susceptible and thus survive lower doses.
2. formulation - short acting drugs exert less selection pressure 3. human factors - e.g. use of an outdated drug 4. size of the refugia |
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true or false:
drugs with longer persistence will exert less selection pressure for resistance to that drug |
false
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name four major parasitic orders of Phylum Arthropoda, Class Insecta
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1. Order Siphnoaptera - fleas
2. Order Diptera - flies 3. Order Phthiraptera - lice (note: suborders Anopleura and Mallophagia) 4. Order Hemiptera - bugs |
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What Phylum, Class, and Order are ticks and mites?
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- Phylum Arthropoda
- Class Arachnida - Order Acari |
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Phylum Arthropoda, Class Insecta major morphological features
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- adults have 6 legs
- body divided into head, throax, and abdomen |
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Phylum Arthropoda, Class Insecta digestive tract pathogenicity
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salivary glands often harbor pathogens
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Phylum Arthropoda, Class Insecta respiratory system
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oxygen diffuses through spiracles, which can be used to ID the insect
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Phylum Arthropoda, Class Insecta nervous system structure
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- ganglia and nerve cords
- target of insecticides |
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development of insects where the larva bears no resemblance to the adult
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complete metamorphosis
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development of insects where the larva looks like a small adult
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incomplete metamorphosis
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what is the basic action of juvenile hormone?
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inhibits metamorphosis
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what is the term used to refer to the phases between insect molts?
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instars
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name the five insect (sub)orders that harbor or are vectors for veterinary parasites
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Order Siphonaptera - fleas
Suborder Mallophagia - biting lice Suborder Anopleura - sucking lice Order Diptera - flies Order Hemiptera - kissing bugs, bed bugs |
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fleas are in what order?
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Order Siphonaptera
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biting lice are in which suborder?
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(Order Phthiraptera)
Suborder Mallophagia |
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sucking lice are in which suborder?
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(Order Phthiraptera)
Suborder Anopleura |
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flies are in which order?
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Order Diptera
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kissing bugs and bed bugs are in which order?
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Order Hemiptera
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Name the orders of venomous or irritant insects
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Order Hemiptera - assassin bugs
Order Coleoptera - blister beetles Order Lepidoptera - urticating caterpillars Order Hymenoptera - bees, wasps, ants |
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assassin bugs are in which order?
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Order Hemiptera
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blister beetles are in which order?
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Order Coleoptera
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urticating caterpillars are in which order?
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Order Leipdoptera
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name the order of bees, wasps, and ants
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Order Hymenoptera
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list the major characteristics of Class Insecta, Order Siphonaptera
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- Fleas
- Macroscopic, usually brown - Wingless - Laterally compressed - Complete metamorphosis |
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cat flea:
- Class - species - host - geographic distribution - sexual dimorphism |
Class Insecta, Order Siphonaptera
Ctenocephalides felis felis - hosts: dogs, cats, ferrets, other animals; the most common flea of cats and dogs - worldwide distribution - females are larger than males |
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Ctenocephalides felis felis life stages
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- three of four stages off of the host
- environmental stages prefer high humidity and warm temperatures 1. Egg; 2. Larva; 3. Pupa; 4. Adult |
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Ctenocephalides felis felis egg
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- once on host, adults are permanent ectoparasites
- females begin laying eggs in a few days; one female can lay up to 1000 eggs in a lifetime, but most don't live that long - eggs laid on host, but fall off - hatch in a few days - warm, humid weather makes eggs hatch faster and more likely to hatch |
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Ctenocephalides felis felis larva
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- slender, white, 2-5 mm
- eat organic debirs, but REQUIRE flea feces; most successful larvae are where animal spends most of its time so that adult fleas drop feces - limited ovement - avoid light (base of carpet pile) - pupate in about a week - hate low humidity |
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Ctenocephalides felis felis pupa
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- sticky, silky coccoon that picks up debris and sand
- if warm and humid: 5 days to adult - adult can stay in pupa a few months |
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Ctenocephalides felis felis adults
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- permanent ectoparasites
- live up to three months |
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Ctenocephalides felis felis minimum life cycle from egg to adult under perfect conditions
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- egg hatches in 2 days
- larval stage lasts for 6 days - pupates in 6 days - total: 14 days egg --> adult |
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Ctenocephalides felis felis life stage population distribution
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adults: 5%
eggs: 50% larvae: 35% pupae 10% |
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Ctenocephalides felis felis temperature effects
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- no stage can survive prolonged cold; house and reservoir hosts overwinter
- killed within 10 days at 37 °F |
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Ctenocephalides felis felis clinical diagnostic signs
|
- adults are visible (remove large numbers)
- flea dirt (feces) - clinical signs (e.g. pruitis, hot spots) |
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what are some clinically important facts of fleas
|
- common cause of vet visit (especially, SE US)
- distrubuted on tailhead, thighs, abdomen, neck - scratching (pruitis) - most extreme pruitis dur to hypersensitivity and/or allergy to flea saliva |
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Ctenocephalides felis felis major clinical signs
|
- hot spots
- vector for tapeworms and Bartonella henselae (cat scratch disease) - anemia; white nictitating membranes in juveniles |
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Name other flea species besides Ctenocephalides felis felis
|
- Ctencephalidea canis - dog fles
- Pulex - human flea - rodent fleas - SW US; vectors for Yersinia pestis; fever, pneumonia, lymphadentitis - Echidnophagia gallinacea - stick tight flea of poultry and pets |
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name some characteristics of lice
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- similar across hosts
- small - wingless - dorsoventrally flattened - often gray or white, some brown - no complete metamorphosis |
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name the two classes of lice and what distinguishes them
|
- Anoplura - sucking lice
- Mallophagia - biting or chewing lice |
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comment on the hosts of lice
|
- mammals and birds
- very host specific (morphology and other factors) |
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how many instars do flea larvae have?
|
three
1. first stage larva: 1-2 mm long 2. second stage larve: 2-3 mm long 3. third stage larva: 3-5 mm long |
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how many instars do lice larvae have?
|
three
1. first stage larva: 1.5 mm long 2. second stage larve: 1.75 mm long 3. third stage larva: 2.0 mm long |
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what is the life cycle of the louse?
|
entire life cycle spent on the host
1. eggs (nits) glued to hairs or feathers 2. three instars of larvae - incomplete metaphophosis 3. adult life cycle minimum is 3 weeks |
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how are lice transmitted?
|
- direct contact or fomites
- very host specific and usually site specific |
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comment on how lice behave if they are off their host
|
- cannot survive long
- biting lice may survive several days if cool and humid |
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how do lice survive over the winter?
|
- microclimate on the skin of hosts is body temp and moist
- animals huddle closer together |
|
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what are the clinical signs of lice infestation?
|
- pruitis
- hair loss and poor coat Severe cases: - anemia - debilitation (can be 2ndary to other problems) |
|
|
clinical importance of lice
|
- uncommon in well-cared-for small animals
- uncommon in horses, but easily contracted and spread - common in food animals, but usually not severe - wild birds: common, usually tolerated - pet birds: uncommon; sometimes outside poultry - wild mammals: common but usually not severe - common in rodents |
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|
lice treatment
|
- self grooming removes lots of lice
- social grooming - pesticides - adults easy to kill; eggs are impervious - repeat ttreatment at or about 2 weeks or use long residuals - usually treat all animals |
|
|
what are the two genera of human lice?
|
Pediculus - head and body lice
Phthirus - pubic lice (crabs) |
|
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how many wings do most flies have?
|
1 pair
|
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what type of metamorphosis do Order Diptera undergo?
|
complete
|
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Family, Genus, species of the house fly and face fly
|
Family Muscidae
Musca domestica - house fly Musca autumnalis - face fly |
|
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what type of flies are Musca domestica and Musca autumnalis?
|
non-biting flies
|
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what is the clinical importance of non-biting flies?
|
- annoyance (can interfere with normal behavior, such as eating)
- disease vectors - eggs often laid in decaying organic material - short generation times |
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what are some general comments on the life cycle of Musca autumnalis?
|
- adult females are parasites; eat bodily secretions
- eggs laid in fresh manure - primarily affects ruminants and horses (face fly) |
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what are some clinically important facts about Musca autumnalis
|
- flies irritate mucosa and can lead to inflammation and tearing
- scrapes the mucosa of the eye to generate tears - transmits bovine pinkeye - Moraxella bovis |
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what is the phylum - order of the true bugs?
|
Phylum: Arthropoda
Class: Insecta Order: Hemiptera |
|
|
what is the genus of bed bugs?
|
Cimex
|
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what are the four stages of the life cycle of Phylum Arthropoda, Class Arachnida?
|
egg, larve, nymph, adult
|
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how many legs do Arachnida have?
|
nymphs and adults: 8
larvae: 6 |
|
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what are the basic parts of the tick and mite?
|
- capitulum (head)
* chelicerae - the serrated "fangs" * hypostome - the "beak" * palps - the large tactile organs positioned laterally - idiosoma: the rest of the body |
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what are some general comments on the typical parasitic mite?
|
- all life stages on host
- usually a short life cycle - transmitted by direct contact and/or fomites - doesn't survive well off the host - one cause of mange |
|
|
what are some characterisits of an atypical parasitic mite?
|
- adults may visit host intermittently
- some stages are free-living |
|
|
what are the three suborders of mites?
|
1. Astigmata
2. Mesostigmata 3. Prostigmata |
|
|
what are the major groups of the Astigmata suborder of mites?
|
Sarcoptic mites and Psoroptic mites
|
|
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name some genera of sarcoptic mites
|
Sacroptes, Notoedres, Knemidocoptes
|
|
|
name some genera of psoroptic mites
|
Psoroptes, Chorioptes, Otodectes
|
|
|
name some genera of the Mesostigmata suborder of mites
|
Dermanyssus, Ornithonyssus
|
|
|
name some of the genera of the prostigmata suborder of mites
|
Demodex, Cheyletiella, Trombiculids (chiggers)
|
|
|
are Astigmata mites seen typically or atypically in domestic animals?
|
typical
|
|
|
are Mesostigmata mites seen tyipcally or atyipcally in domestic animals?
|
atypical
|
|
|
are Prostigmata mites seen typically or atypically in domestic animals?
|
some are typical (Demodex and Cheyletiella)
some are atypical such as Trombiculids (chiggers) |
|
|
what are some characterisics of astigmatid mites?
|
- sarcoptic mites have round, short legs and are burrowing
- psoroptic mites are oval with longer legs |
|
|
what are some characterisics of mesostigmatid mites?
|
bigger and longer mouth parts with respect to the other suborders
|
|
|
what are some characterisics of prostigmatid mites?
|
Demodex - cigar-shaped with legs (to fit into hair follicle and sebaceous glands)
Cheyletiella - palpal claws Trombiculid mites (chiggers) - visible, often orange |
|
|
what are the characteristics of sacroptic mites: type? genera? morphology? life cycle time? transmission?
|
- astigmatid
- Genera: Sacroptes, Notoedres, Knemidocoptes - round bodies; last two pairs of legs are short - the burrow; females lay eggs in tunnels in the epidermis - life cycle lasts about 3 weeks - easily transmitted between animals |
|
|
why do we dislike flies?
|
- annoyance
- bites (dermatitis) - disease transmission - parasitism by larval flies (obligate and facultative) |
|
|
what are the three types of flies that cause problems?
|
1. adult biting
2. adult non-biting 3. larval |
|
|
On what do Musca autumnalis females feed in order to reproduce?
|
Animal secretions
- females scrape the mucous membranes (of the eyes) to stimulate tears and feed on other bodily secretions as a protein source. |
|
|
what is a common disease spread by Musca autumnalis?
|
bovine pinkeye (Moraxella bovis)
|
|
|
where are Musca autumnalis adults typically located?
|
on the animal face around the eyes
|
|
|
Stable Fly Order --> species
|
Order Diptera
Family Muscidae Stomoxys calcitrans |
|
|
Horn Fly Order --> species
|
Order Diptera
Family Muscidae Haematobia irritans |
|
|
Mosquito Order and Family
|
Order Diptera
Family Culicidae |
|
|
Horse Flies Order and Family
|
Order Diptera
Family Tabanidae |
|
|
Deer Flies Order and Family
|
Order Diptera
Family Tabanidae |
|
|
Black Flies Order - Genus
|
Order Diptera
Family Simulidae Simulium |
|
|
Midges, no see ums, punkies Order - Genus
|
Order Diptera
Family Ceratopogonidae Culicoides |
|
|
sheep ked and flat flies Order and Family
|
Order Diptera
Family Hippoboscidae |
|
|
sand flies Order and Family
|
Order Diptera
Family Psychodidae |
|
|
tsetse flies Order and Family
|
Order Diptera
Family Glossinidae |
|
|
Stomoxys calcitrans
|
Stable fly
|
|
|
Haematobia irritans
|
Horn fly
|
|
|
Family Tabanidae
|
Horse flies, deer flies
|
|
|
Family Culicidae
|
Mosquitoes
|
|
|
Simulium spp.
|
black flies, buffalo gnats
|
|
|
Culicoides spp.
|
midges, no see ums, punkies
|
|
|
Family Hippoboscidae
|
sheep ked, flat flies
|
|
|
Family Psychodidae
|
sand flies
|
|
|
Family Glossinidae
|
tsetse flies
|
|
|
What is the main morphological feature that differentiates Stomoxys calcitrans from Musca domestica
|
(Stable fly versus house fly)
a protruding proboscis |
|
|
comment on the feeding habits of Stomoxys calcitrans
|
(Stable fly)
- visits the host 1-2 time per day - prefers to bite leg and flank |
|
|
where does Stomoxys calcitrans prefer to lay its eggs?
|
(Stable fly)
in decaying vegetation, manure. Manure/compost and feed toughs are perfect |
|
|
what is the clinical importance of Stomoxys calcitrans?
|
(stable fly)
- annoyance - fly bite dermatits |
|
|
Where do Haematobia irritans typically live?
|
(horn fly)
- The back and ventrum of cattle and horses - they are resident parasites |
|
|
where do Haematobia irritans lay their eggs
|
(horn fly)
fresh manure - almost right after it leaves the hole |
|
|
what are the feeding habits of Haematobia irritans?
|
they bite, feeding up to 20 times per day
|
|
|
what is the clinical importance of Haematobia irritans?
|
- annoyance to the point where you may see decreased production
|
|
|
Family Tabaindae morphology
|
(horse, deer flies)
- big, large eyes, stout body - deer lies have striped wings |
|
|
where do Family Tabanidae typically lay their eggs?
|
(horse, deer flies)
near water |
|
|
what is the clinical importance of family Tabanidae?
|
(deer, horse flies)
- very painful bites - excellent disease vectors |
|
|
Family Culicidae morphology
|
(mosquitoes)
- small, delicate flies with long mouthparts |
|
|
Family Culicidae life cycle
|
- females take blood meals
- eggs laid in water |
|
|
Family Culicidae clinical importance
|
(mosquito)
- annoyance - fly bite allergies - important disease vector |
|
|
where do Family Simulidae lay their eggs?
|
(black flies, buffalo gnats)
in rapidly moving water |
|
|
what is the clinical importance of Simulium spp?
|
(black flies, buffalo gnats)
- annoyance: will swarm and bits; in the Eastern US, see dogs and horses with affected ears - fly bite dermatitis - disease vector--US not as much--Avian hemoprotozoa - rare fatalities |
|
|
Culicoides spp. life cycle
|
(no-see-ums, midges)
- larvae found in moist soil or aquatic |
|
|
Culicoides clinical importance
|
(midges, no-see-ums)
- annoyance, mostly in horses - allergy, sometimes called a "sweet itch" - vector of bluetongue |
|
|
list some types of fly control in large animal environments
|
- window screens and doors
- traps - get rid of manure - feed pesticides that will be eliminated in manure to kill larvae - use parasitic wasps |
|
|
fly control on food animals
|
- dust bags, back rubbers
- ear tags for cattle - pour-on pyrethroids and macrolides |
|
|
fly control for horses
|
- repellants, sprays, pour-ons
- pyrethroids most common - masks and fly sheets - physical barriers |
|
|
infection due to the invasion of tissues or cavities of the body by the larvae of dipterous insects
|
myiasis
|
|
|
what are the two types of myiasis?
|
- cutaneous - fly strike
- internal - grubs, warbles, bots |
|
|
how is a myiatic fly larva specifically identified?
|
examination of spiracles by an entomologist
|
|
|
list some common names for flies that infect via myiasis
|
Blow flies
Flesh flies Horse bots Cattle grubs Rodent bot flies Sheep nasal bot Deer nasal bot |
|
|
Cochliomyia hominovorax
|
Blow flies (screw worms)
|
|
|
Family Calliphoridae
|
Blow flies
Cochliomyia hominovorax |
|
|
Family Sarcophagidae
|
Flesh flies
|
|
|
Family Gasterophilidae
|
Gasterophilus spp.
Horse Bots |
|
|
Family Hypodermatidae
|
Hypoderma spp.
Cattle grubs |
|
|
Family Cuterebridae
|
Cuterba spp.
Rodent bot flies |
|
|
Family Oestridae
|
Oesteris ovis - sheep nasal bot
Cephenemyia spp. - deer nasal bot |
|
|
Gasterophilus spp.
|
horse bots
|
|
|
horse bots genus
|
Gasterophilus
|
|
|
Hypoderma spp.
|
Cattle grubs
|
|
|
cattle grubs Genus
|
Hypoderma
|
|
|
Cuterbera spp.
|
rodent bot flies
|
|
|
rodent bot flies genus
|
Cuterebra
|
|
|
Oestrus ovis
|
sheep nasal bot
|
|
|
Cephenemyia spp.
|
deer nasal bot
|
|
|
Sheep nasal bot Genus and species
|
Oestrus ovis
|
|
|
deer nasal bot Genus
|
Cephenemyia
|
|
|
which type of flies cause fly cutaneous myiasis (fly strike)?
|
Calliphorids - blow flies
Sacrophagids - flesh flies |
|
|
what does a Calliphorid look like?
|
(blow fly - cutaneous myiasis)
metallic green, blue, bronze |
|
|
what does a Sarcophagid look like?
|
(flesh fly - cutaneous myiasis)
loks like a big house fly, often with a red tip on the abdomen |
|
|
what is the life cycle for fly strike flies
|
(cutaneous myiasis)
- eggs laid in organic material - females affected by secretions from wounds, fecal matter, etc. - larvae feed on necrotic material |
|
|
clinical signs of fly strike
|
(cutaneous myiasis)
- maggots - animal may be depressed from toxemia |
|
|
why should large animals be castrated/dehorned before fly season
|
because Calliphorids (blow flies) and Sarcophagods (flesh flies) can infect via cutaneous myiasis (fly strike)
|
|
|
what is the Genus and species name for the screwworm
|
Cochliomyia hominovorax
|
|
|
what is Cochliomyia hominovorax and what makes it different from other members of its order?
|
(cutaneous myiasis - fly strike)
- screwworm - requires living tissue - much more severe disease - because it was eradicated, all cased must be reported |
|
|
what are the common names for the larvae of flies that undergo internal myiasis?
|
bots, grubs, warbles
|
|
|
what is the basic life cycle of flies that undergo internal myiasis?
|
- adults look hairy, like bees. They don't feed, breed, and die rapidly. animals will often avoid them
- larva is an obligate internal parasite - larva leaves host, then pupates in the environment |
|
|
Gastrophilius spp. life cycle
|
(horse bots - internal myiasis)
- eggs laid on face or eggs and are stimulated by warm, moist air - larvae migrate to mouth, and in gum and tongue - bots move to stomach and remain for 10-12 months - crap out the bots - they pupate on ground and produce adults |
|
|
Gastrophilus spp. clinical signs
|
(horse bots - internal myiasis)
- not very pathogenic - no specific signs - sometimes mouth lesions present - RARELY stomach ulcers/perforation |
|
|
Gastrophilus spp. diagnosis and treatment
|
(horse bots - internal myiasis)
- see flies or eggs - moxidectin or ivermectin - use warm water to wash legs to stimulate hatching and then kill the bastards - bot combs |
|
|
Hypoderma bovis
Hypoderma lineatum LIFE CYCLE |
(cattle grubs; warbles; heel flies - internal myiasis)
- Cattle hate the adults - gadding - Eggs glued to hairs of lower body - larvae hatch and burrow through skin and migrate through tissue to site of development - reside there 2-4 months migrate to subQ, on back, make a breathing hole and remain 5-8 weeks - pupate on ground |
|
|
Hypoderma bovis - where do they migrate to for develpment?
|
(cattle grubs - internal myiasis)
spinal cord - 2-4 months subQ on back with breathing hole 5-8 weeks |
|
|
Hypoderma lineatum - where do they migrate for development?
|
(cattle grubs - internal myiasis)
esophagus - 2-4 months subQ on back with breathing hole 5-8 weeks |
|
|
how are cattle grubs treated?
|
macrolides or organophosphates. Need to treat after grubs make it to the back so that there isn't internal damage
|
|
|
Oestrus spp. what are they? What do they do? How do we kill them?
|
(internal myiasis)
- nasal bot - parasite of small ruminants - macrolides |
|
|
Life cycle of Cuterebra spp.
|
(rodent bot flies - internal myiasis)
- parasites of rodents, rabbits - eggs laid near burrows or along trails - larva picked up by rodent or rabbit - develop subQ cyst - pupate on ground |
|
|
what other hosts besides rodents and rabbits can Cuterebra spp. infect? Clinical signs?
|
(rodent bots - internal myiasis)
dogs and cats - looks like a boil on head and neck (furuncle) - secondary infection |
|
|
Cuterebra spp. treatment
|
(rodent bot fly)
- remove carefully, use antibiotics as needed |
|
|
family of bloodsucking flies that have flat bodies
|
Order Diptera
Family Hippoboscidae |
|
|
Family Hippoboscidae, common name and Genus of a no-longer common pest
|
sheep and goat "ked"; flat fly
Melophagus |
|
|
Triatomid bugs: order, common names
|
Order Hemiptera
Kissing bugs; assassin and wheel bugs |
|
|
what disease do kissing bugs spread?
|
(Order Hemiptera, Family Triatomidae)
Trypanosoma cruzi (trypanosomiasis; Chagas' Disease in humans) |
|
|
Cimex
|
bed bugs
|
|
|
common bed bugs Genus
|
Cimex
|
|
|
how are sarcoptic mites diagnosed?
|
- skin scraping (scrape the periphery)
- may find mites or eggs in fecal |
|
|
comment on the species variants, hosts, and prevalance of Sarcoptes scabiei
|
- separate variety for most common domestic host species
- does not seem to cross-infest - most often seen on dogs in the U.S. - also in pigs - rare in ruminants and horses |
|
|
Comment on the clinical signs of Sarcoptes scabiei var canis
|
- like hairless ares or area with thin hair
- intense puritis - chronic sarcoptic mange leads to alopecia, thickened, wrinkled skin, secondary bacterial infection, and self-inflicted trauma |
|
|
How is Sarcoptes scabiei var canis treated?
|
- treat all animals
- macrolides and amitraz - lime sulfur in young pups - extensive environmental treatment |
|
|
What is the importance of and treatment for Sacroptes in swine?
|
- lost production is often seen
- old sows act as carriers - eradicable from a closed system with macrolides |
|
|
what is Notoedres cati?
|
sarcoptic mange mite of the cat. Rare in the US
|
|
|
what species of sarcoptic mites infest poultry and pet birds?
|
Knemidocoptes spp.
|
|
|
What is Knemidocoptes and its life cycle?
|
sarcoptic mange of pet birds and poultry.
Life cycle: - most on non-feathered portion of body - legs in poultry (scaly leg mite) - face in pets (scaly face mite) - mites burrow in and cause crusty, scaly lesions - honeycomb appearance |
|
|
how is Knemidocoptes treated?
|
(bird mites)
Treated with macrolides |
|
|
What type of mites are psoroptic mites?
|
astigmatic mites
|
|
|
what are Psoroptes spp.
|
astigmatic, Psoroptic mites
|
|
|
what are Chorioptes spp.
|
astigmatic, Psoroptic mites
|
|
|
what are Otodectes spp.
|
astigmatic, Psoroptic mites
|
|
|
what are some general characterisitcs of psoroptic mites?
|
- surface dwellers, not burrowers
- look like sarcoptic mites, but oval, not round, and have longer legs - short life cycle - minimum, 2 weeks - diagnosed by skin scraping (except for ear mites) - treated with macrolides |
|
|
what psoroptic mites commonly infest ruminants?
|
Psoroptes ovis
Chorioptes spp. |
|
|
what psoroptic mites commonly infest rabbits and where on they body can they be found? WHat other animals can they infect?
|
Psoroptes cuniculi
- infect the ears - alpacas, goats, rarely horses |
|
|
what are the most common species of psoroptic mites that infect ruminants and horses and where on they body can they be found?
|
Chorioptes spp. (host specific)
- cattle: tailhead, udder, perianal region - small ruminants: leg, lower body - horses: legs |
|
|
Otodectes cynotis: what is it, what does it infect, and what are the clinical signs, and how it it treated?
|
- psoroptic mite
- infects dogs, cats, ferrets - parasite of the ear canal - otitis externa, "coffee grounds" in the ear, causes intense puritis - treatment: clean ear, macrolides or pyrethrins |
|
|
what is the life cycle of Demodex?
|
- species specific
- lives in the hair follicles and sebaceous glands - transmission occurs from mother to infant shortly after birth - normal skin fauna |
|
|
how is Demodex diagnosed and what is its clinical importance?
|
- deep skin scraping
- eggs and mites in feces - important in dogs - when mites proliferate beyond normal levels, clinical signs will present - interfere with follicles and gland function - can lead to inflammation and secondary infection |
|
|
what are the two forms of Demodecosis?
|
- localized form, usually in pups. 90% resolve spontaneously
- generalized, chronic form |
|
|
what are the clinical signs of canine demodecosis?
|
- Alopecia
- Erythema - Seborrhea - Pyoderma - Pruritus later |
|
|
how is Demodex treated in dogs?
|
- amitraz
- macrolides - selective breeding, since there is a genetic predisposition for demodecosis |
|
|
what is walking dandruff?
|
- Cheyletiella spp. of mites
- dogs, cats, rabbits - surface mite - often few signs, but can show scrufy dandruff and pruitis |
|
|
what are the hosts, life cycle, and clinical importance of Trombiculid mites?
|
(chiggers, harvest mites)
- infests a wide variety of animals and people - life cycle: only larvae are parasitic; acquired from the environment; attach for several days - pruitis lasts after mites are gone |
|
|
how are Trombiculid mites diagnosed and treated.
|
(chiggers, harvest mites)
- red or orange mites on face and ears - pruitic lesions - treated with acaricides if mites are present and there are symptoms |
|
|
what species of mesostigmatic mites infect birds?
|
Onithonyssus sylvarium - northern fowl mite
Dermanyssus spp. - red poultry, wild bird mite |
|
|
what is the life cycle and clinical importance of Ornithonyssus sylvarium?
|
(mesostagmatid mite; northern fowl mite)
- avian blood feeder - entire life cycle on host - lower weight gain and egg production |
|
|
what is the clinical importantce of rodent Ornithonyssus spp.?
|
(mesostagmatid mites)
- can infect humans and other pets |
|
|
what is the life cycle and clinical importance of Dermanyssus spp.?
|
(mesostagmatid mite; red poultry, wild bird mite)
- on host at night, blood-sucking - find red or black mites in the environment during the day - can be a pest to people |
|
|
What phylum, class, and family are the soft ticks?
|
Phylum Arthropoda
Class Arachnida Family Argasidae |
|
|
What phylum, class, and family are the hard ticks?
|
Phylum Arthropoda
Class Arachnida Family Ixodidae |
|
|
how can you easily tell a soft tick from a hard tick?
|
- a soft tick has a leathery, wrinkled body
- capitulum not visible on the dorsal view - no scutum |
|
|
What is the basic life cycle for Ixodidae?
|
Egg (no legs) --> hatch -->
Larvae (3 pairs of legs) --> molt --> Nymph (4 pairs of legs) --> molt --> Adult (4 pairs of legs) |
|
|
*** which tick causes Lyme disease?
|
Ixodes scapularis
|
|
|
how can you tell a male Ixodes scapularis from a female (adults)?
|
- both are brown/black
- female is larger - female's scutum only goes 1/2 way down the back, whereas the male's goes all the way |
|
|
what part of the tick is used to penetrate the skin?
|
hypostome
|
|
|
what structure are a tick's mouthparts attached to?
|
basis capituli
|
|
|
what is the prehensile mouthpart of the tick?
|
palp
|
|
|
what is the serrated mouthpart of the tick?
|
chelicerae
|
|
|
these are scallop-like projections from the back of a tick
|
festoons
|
|
|
has a hexagonal basis capituli
|
Rhipicephalus sanguineus
|
|
|
what are the two major anatomical features of tick used in its identification?
|
basis capituli and the palps
|
|
|
if a tick has markings on its back, what is it said to be?
|
ornate
|
|
|
has festoons and is ornate
|
Dermacentor variabilis
|
|
|
tick that is not ornate, no festoons, anterior anal groove
|
Ixodes spp.
|
|
|
what special anatomical feature do Ixodes spp. possess and what common disease to they carry?
|
(hard tick)
- anterior anal groove - they carry Lyme disease |
|
|
What is the life cycle of Rhipacephalus annulatus and what disease does it spread?
|
- Rhipicephalus transmits Babesia bigemina.
A one-host tick: egg hatches, larva emerges, larva finds host, feeds on host, stays and molts on host, nymph stays, and adult feeds. |
|
|
tick that has a single spot on the scutum.
|
Ambyomma americanum females
|
|
|
a tick waiting on a trail (for example) for a host to arrive is said to be what?
|
questing
|
|
|
what is a major genus of soft ticks that lives in the host's den or nest?
|
Nidicolous
|
|
|
besides Nidicolous, where are you likely to find soft ticks?
|
paths, trails, etc., where a host is likely to pass
|
|
|
how can you tell a nymph from an adult tick?
|
in adult, a genital aperture is present on the ventrum, cranial to the anal pore
|
|
|
most hard ticks have how many hosts?
|
three (Rhipacephalus annulatus is an exception, with only one host)
|
|
|
how many hosts do soft ticks typically have?
|
many
|
|
|
What is the process of tick feeding and disease transmission?
|
- pool feeders
- excrete substances that affect hemostasis and immune response - concentrate blood-meal-water back into host, which transmits pathogens and toxins - Intracellular digestion-blood stays in gut long periods-helps protect pathogens - most ticks require several days to complete feeding; in most cases, the tick needs to feed an appropriate amount in order to transmit pathogen |
|
|
how long do ticks in the US typically need to feed before Lyme disease is transmitted?
|
48 hours
|
|
|
what three major factors affect the transmission of a pathogen from tick to host?
|
- Immunity of host may increase transmission time
- Different pathogens take different lengths of time to be transmitted by the same tick species - Different genera of ticks may take different times to transmit the same pathogen |
|
|
What is the life cycle of a 1-host tick?
|
1. eggs hatch into six-legged larvae
2. larvae remain on hosts and become adults after 2 molts 3. females drop off the host to lay eggs 4. gravid females lay eggs in the environment |
|
|
what is the life cycle for a 3-host tick?
|
1. Fall Year 1: eggs hatch into 6-legged larvae
2. Fall/Winter Year 1: Larvae find their first host and feed. 3. Fall Year 2: larvae molt into nymphs leave their first host. 4. Spring Year 3: nymph attaches to second host 5. Summer Year 3: nymph leaves second host and molts into an adult. It then overwinters. 5. Spring Year 4: Adult attaches to third host and feeds and mates 6. Fall Year 4: gravid females drop off host and lay their eggs. 7. the miracle of nature repeats |
|
|
Name two species of soft ticks
|
Argas persicus (Fowl tick)
Otobius megnini (Spinose ear tick) |
|
|
The black-legged or deer tick: how many hosts? clinical importance?
|
Ixodes scapularis
- 3 host tick - transmits Borllia burgdorferi (Lyme disease) |
|
|
What diseases can Ixodes scapularis and Ixodes pacificus transmit?
|
(deer tick)
- Lyme disease - Babesia (humans) - Anaplasma phagocytophilium (human granulocytic anaplasmosis) |
|
|
What diesases can Amblyoma americanum transmit?
|
(lone star tick)
- RMSF - STARI (southern tick associated rash illness) - ehrlichiosis |
|
|
Amblyoma americanum sexual dimorphism
|
(lone star tick)
- only adult female has white dot on the scute - females are larger than males |
|
|
Amblyoma maculatum. Common name, hosts, ID, disease
|
- Gulf Coast Tick
- Infects cows and dogs - Ornate and festooned - American canine hepatozoonosis |
|
|
what is the species of the American Dog Tick? How many hosts? What are its hosts? Diseases?
|
Dermacentor variabilis
- 3-host tick - larvae and nymphs feed on mice and small mammlas - adults feed on dogs, cattle, humans, etc. - transmits RMSF and transmits Cytauxzoan felis to cats |
|
|
Dermacentor variabilis ID
|
Ornate, festoons
|
|
|
What species is the brown dog tick? Hosts? Diseases?
|
Rhipicephalus sanguineus
- 3-host tick, but prefers the same host for all stages - can reproduce in the home/kennel - Diseases: Ehrlicia canis; A. Platys; Babesia canis; Babesia gibsoni; H. canis |
|
|
Rhipicephalus sanguineus ID
|
(brown dog tick)
- basis capituli has lateral expansions (hexagon shaped) - non-ornate - has festoons |
|
|
Texas cattle fever tick. Species? Hosts? Clinical significance?
|
Rhipecephalus (Boophilus) annulatus
- 1 host tick - Eradicated from US - still in Mexico - reportable tick |
|
|
Clinical signs and treatment of tick paralysis
|
- Ascending motor paralysis
- Toxic substances in saliva - Tick or ticks usually are found on neck or near head - Removal of tick is the treatment |
|
|
what are the most common species of ticks that cause tick paralysis?
|
Dermacentor variabilis
Dermacentor andersoni Amblyomma americanum Amblyomma maculatum |
|
|
Name four common species of flagellates that infect small animals in the US.
|
Giardia spp.
Tritrichomonas foetus Leishmania infantum Trypanosoma cruzi Others: Babiesia spp. Cytoxzooan felis Hepatozoon americanum |
|
|
name six coccidia and coccidia-like protoans
|
Eimeria spp.
Isospora spp. (pigs only) Neospora caninum Toxoplasma gondii Sarcocystis neurona Cryptosporidium spp. |
|
|
What are the four major drug targets for ciliates and what drugs are used?
|
- Membrane: ionophores
- Mitochondria: decoquinate - Microtubules: benzimidazoles - Nucleus: many agents |
|
|
what are the two ways in which ciliophora, sarcomastigophora, and apicomplexa multiply?
|
asexually:
longitudinal binary fission transverse binary fission schizogony |
|
|
a process in where a protozoan forms multiple nuclei and then divides into multiple clones
|
schizogony
|
|
|
what is the basic process of sexual reproduction in apicomplexans and sarcomastigaphorans?
|
- production of micro- (male) and macro- (female) gamonts
- production of haploid gametes from the gamonts - fusion of gametes to form a diploid zygote, which may produce a cyst |
|
|
Liberation of a parasite from its cyst.
|
excystation
|
|
|
what are the three major phyla of Kingdom Protista that we are studying?
|
- Phylum Ciliophora- The ciliates
- Phylum Sarcomastigophora - The ameba and flagellates - Phylum Apicomplexa - The coccidial and malarial-like parasites |
|
|
What are two species of infectious ciliophors and their hosts?
|
Balantidium coli - pigs, humans, and primates
Ichthyopthirius multifiliis - pet fish and farm raised fish |
|
|
what are the two main stages of the flagellate life cycle?
|
- cyst
- zoite |
|
|
what is the major pathogenic trichomonad, what are its hosts, and what is its clinical significance?
|
Tritrichomonas foetus
- Infects the large intestine of cats, dogs, and pigs - Infects the reproductive organs of cattle - leads to abortion of calves - bulls are carriers and should be culled |
|
|
how are Tritrichomonads distinguished from Giardia microscopically?
|
Tritrichomonads have a "jerky" motion, whereas Giardia move more smoothly.
|
|
|
how large is a Tritrichomonad?
|
about 5 microns wide
|
|
|
what are clinical signs of Tritrichomonas foetus in cats?
|
- chronic, waxing and waning large bowel diarrhea
- diarrhea is often of cow-pie consistency, malodorous, and occasionally contains mucus, or fresh blood - involuntary fecal dribbling and inflammation of the anus bloody diarrhea |
|
|
What are the two subphyla of Phylum Sarcomastigophora?
|
Subphylum Sarcodina (Ameba)
Subphylum Mastigophora |
|
|
How do Subphylum Mastigophora move, divide, and where in the body do they infect?
|
- Have flagella all or part of life cycle
- Move by flagella - Divide by longitudinal binary fission - Mucosal flagellates live in mucosa or lumen - Blood/tissue flagellates live in blood or tissues |
|
|
how is Giardia transmitted?
|
fecal cysts
|
|
|
How is Tritrichomonas foetus transmitted?
|
direct or sexual contact
|
|
|
How are Leischmania and Trypanosoma transmitted?
|
arthropod vectors
|
|
|
What is the life cycle of Giardia?
|
Giardia cysts are ingested in water or in contaminated material from the environment. The cysts excyst and trophozoites develop in small intestine
|
|
|
What is characteristic of the diarrhea caused by Giardia?
|
Fatty, does not contain blood, smells bad
|
|
|
***How is Giardia diagnosed?
|
- Demonstrate trophozoites/cysts in smears or cysts in fecal flotations
- Cysts are shed intermittently!!!! - Must examine 3 samples taken over a 1 week period - Zinc sulfate solution flotation and iodine stain for cysts - IDEXX SNAP test is highly effective for patent and occult infections |
|
|
how large are Giardia cysts?
|
about 12 microns
|
|
|
What are the 7 assemblages of Giardia and their hosts?
|
- Assemblage A - Humans, dogs, beavers, livestock
- Assemblage B - Humans, dogs, beavers - Assemblage C - dogs - Assemblage D - dogs - Assemblage E - livestock - Assemblage F - cats - Assemblage G – rats |
|
|
What are typical drug treatments for Giardia?
|
- Metronidazole
- Benzimidazoles: fenbendazole, febantel, albendazole |
|
|
what stage of the Giardia life cycle causes diarrhea?
|
trophozoites
|
|
|
Giardia vaccine: name? what is it? Minimum animal age? Vaccination schedule?
|
- Fort Dodge
- Killed trophozoites plus adjuvant - Healthy animals 8 weeks of age or older - 2 subQ doses given at 2-4 weeks apart - Boost yearly |
|
|
How does Giardia cause infection and how does infection develop?
|
Giardia cysts are ingested in water or in contaminated material from the environment. The cysts excyst and trophozoites develop in small intestine
|
|
|
***What is the most important aspect of properly diagnosing a Giardia infection?
|
- Diagnosis by fecal examination
- 3 examinations!! - Zinc-Sulfate is best |
|
|
How is coccidia diagnosed?
|
find oocysts in the feces.
|
|
|
Coccidia is a general term for many species. Name some species of coccidia infection and their hosts.
|
- Eimeria of chickens and cattle
- Isospora dogs and cats - Toxoplasma gondii cats – any warm-blooded animal - Neospora caninum dogs - cattle - Sarcocystis neurona (EPM) opossum-horses |
|
|
what organelle is common to all coccidia invasive stages, what does it do, and what are its "parts"?
|
- apical complex
- allows pinocytosis of the zooite into an intracellular parasitophorous vesicle -apical complex is comprised of apical and polar rings, a conoid, and rhoptry |
|
|
how is coccidia transmitted?
|
fecal-oral
|
|
|
comment on Eimeria hosts
|
(coccidia)
Eimeria species have one host. (chicken, cattle, sheep, and goats) |
|
|
***Comment on Isospora hosts
|
Isospora species have one host but most can use a paratenic host.
|
|
|
Who are the hosts for Toxoplasma gondii?
|
A two-host parasite, Toxoplasma gondii usually has an intermediate host, which can be many mammals. Cats are the definitive.
|
|
|
Comment on Sarcocystis hosts
|
(coccidia)
Sarcocystis species must use an intermediate host. Many definitive. |
|
|
How do apicomplexans multiply asexually in the host?
|
Asexual reproduction is by schizogony. A uninucleate stage becomes a multinucleate schizont and then cytoplasmic division occurs to produce individual parasites (merozoites).
|
|
|
how do apicomplexans reproduce sexually in the host?
|
- Sexual stages are macrogamonts (female) and microgametes (male) stages.
- Fertilization results in the production of a zygote that becomes the oocyst. |
|
|
how is a coccidia oocyst clinically determined to be pathogenic or not?
|
ID based on characteristic structure of their sporulated oocysts.
|
|
|
***What does a sporulated Isospora oocyst look like?
|
- egg shaped
- about 20 microns wide - 2 sporocysts each containing 4 sporozoites |
|
|
***What does a sporulated Eimeria oocyst look like?
|
oocysts-have 4 sporocysts that each contain 2 sporozoites. There are 8 sporozoites total per oocyst
|
|
|
what causes sporozoite activation in coccidia oocysts?
|
Trypsin and bile in stomach and intestine
|
|
|
where do coccidia oocysts sporulate?
|
Outside the host. They are eliminated unsporulated and then sporulate in the environment.
|
|
|
What defines the prepatent period for coccidia oocysts?
|
the number of days it takes for oocysts to appear in the feces after the hosts ingests sporulated oocysts.
|
|
|
comment on the clinical signs and pathogenesis of coccidia
|
- The rupture of infected cells and release of merozoites cause tissue destruction.
- Villous atrophy - malabsorption - Hemorrhage - blood loss - Diarrhea - may or may not be bloody; diarrhea is the main clinical sign |
|
|
What are clinical signs of bovine coccidiosis?
|
- Bloody diarrhea, weight loss, pneumonia, death. Most less than 1 year
- Nervous coccidiosis--CNS signs associated with Eimeria zuernii infection in cattle - Stress induced coccidiosis (Winter coccidiosis)-outbreaks that occur about 2 weeks after cattle are stressed |
|
|
What are clinical signs of porcine coccidiosis?
|
(Isospora suis)
Diarrhea in 8 to 14 day-old pigs Diarrhea is fluid but not bloody Pigs continue to nurse Pigs may die before oocysts are excreted |
|
|
what is a spurious oocyst? In what hosts are they found? What species are they usually and what can they be misidentified as?
|
- a non-pathogenic oocyst in dogs and cats. There is a cap on the oocyst.
- These are usually Eimeria and can be confused with Isospora |
|
|
what species of coccidia is common to rabbits? Where in the body does it infect? What are the pathological signs?
|
- Eimeria stiedai
- intestinal and hepatic infections - enlarged liver and bile duct hyperplasia |
|
|
what species is the major reservoir host for Leischmania?
|
dogs
|
|
|
***where in the US can you find Leischmania infantum?
|
foxhounds
|
|
|
what is the major vector for Leischmania in the US?
|
sand fly
|
|
|
what is the life cycle of Leischmania?
|
1. vector bites hosts and injects promastigotes
2. promastigotes taken up by cells 3. promastigotes divide and metamorphse into amastigotes 4. amastigotes rupture cell and infect other cells 5. free amastigotes taken up by the vector where they undergo further development into promastigotes |
|
|
where is Leischmania typically found in mammals? In sand flies?
|
- amastigotes in the mononuclear (reticuloendothelial) cells and lymphoid cells (especially macrophages)
- promastigotes found in the sand fly pharynx |
|
|
what are the clinical signs of Leischmania infantum?
|
- In US, think Foxhounds or dogs that have traveled to endemic areas
- Skin lesions, weight loss, lymphadenopathy - Ocular lesions, nose bleed, lameness - Anemia, renal failure, diarrhea |
|
|
Comment on Leischimania vaccine
|
- Leishmune- 76-80% effective in Brazil
- 92% effective in France - Contains a glycoprotein component made from Leishmania promastigotes and QS21-saponin as an adjuvant |
|
|
how is Leischmania diagnosed clinically?
|
- IFA (immunofluorescence assay) test
- Amastigotes in smear - rK39 dip stick test |
|
|
How do cryptosporidia multiply asexually and transform into the sexual stage?
|
- Sporozoite becomes a (multinucleate) schizont
- Schizonts produce merozoites - Merozoites become schizonts (2nd) and make 2nd merozoites - Last merozoites become sexual stages |
|
|
how do cryptosporidia merozoites become oocysts?
|
- Last generation merozoites become sexual stages
- Macrogamont (egg) = female - Microgamont makes many microgametes (sperm) - Fertilization and oocyst |
|
|
how do cryptosporidia oocysts differ from coccidia oocysts?
|
- Has an oocyst like coccidia
- No sporocyst – 4 sporozoites - Develops in microvillus - Excreted fully sporulated - Anticoccidial drugs do not work |
|
|
what is characteristic of the diarrhea caused by cryptosporidium infection?
|
watery, non-bloody
|
|
|
what is the definitive host for Toxoplasma gondii?
|
cats
|
|
|
what is the life cycle for Toxoplasma gondii?
|
- Sporozoites (oocysts) MUST become tachyzoites in the intermediate host including cats
- Tachyzoites can become bradyzoites - Bradyzoites can become tachyzoites - Only bradyzoites can make stages (schizonts, merozoites, and oocysts) in cats |
|
|
how are Toxoplasma gondii bradyzooites infectious?
|
Since they are dormant in the viscera of the host, they must be eaten by another animal to become infected.
|
|
|
why specifically is Toxoplasma gondii dangerous to a fetus?
|
Because the tachyzoites, being apicomplexans, can pass through the placenta and into the fetus
|
|
|
Comment on the 2-host life cycle of Toxoplasma gondii
|
- Tissue cysts (asexual stages) are in the intermediate host
- Sexual stages and oocysts are in the feline definitive host |
|
|
how is Toxoplasma gondii transmitted?
|
- from oocysts excreted by cats
- from ingestion of bradyzooites from intermediate hosts - mother to fetus |
|
|
How large are Toxoplasma gondii oocysts?
|
round, 10 microns
|
|
|
What life stage of Toxoplasma gondii must be ingested by cats to produce oocysts?
|
ONLY the bradyzooites from raw/undercooked meat or tissue
|
|
|
***Comment on the entero-epithelial stages of Toxoplasma gondii
|
- Cats ONLY
- Bradyzoites give rise to EE stages - 5 types of EE schizonts - Produce T. gondii sexual stages and oocysts |
|
|
Comment on the various transformation of the different "zooites" of Toxoplasma gondii
|
- Sporozoites MUST become tachyzoites in the intermediate host including cats
- Tachyzoites can become bradyzoites - Bradyzoites can become tachyzoites - EE stages (schizonts, merozoites, and oocysts) only in cats |
|
|
what is the major vector for Trypanasoma cruzi?
|
triatomid bugs (e.g. kissing bugs, assassin bugs)
|
|
|
What specific feature allows for the identification of Trypanosoma and Leischmania microscopically?
|
They have a kinetoplast
|
|
|
What are the four life cycle stages of kinetoplastids, where do they live, and in what species do they exist?
|
- Promastigotes are stages transmitted by the vector (sandfly; only Leishmania)
- Epimastigotes are stages in the insect vector (T. cruzi only) - Amastigotes are in host cells in tissue (both T. cruzi and L. infantum) - Trypomastigotes are in blood and in insect vector (T. cruzi only) |
|
|
What is the infective stage of Trypanosoma cruzi from the vector?
|
Trypomastigote
|
|
|
How can you distinguish Trypanosoma cruzi and brucei microscopically?
|
- T. Cruzi is C-shaped and has a very large kinetoplast
- T. brucei is skinny, straighter, and has a smaller kinetoplast |
|
|
what disease does Trypanosoma cruzi cause?
|
Chagas' disease
|
|
|
What is the life cycle of Typanosoma cruzi?
|
1. Triatomine bug takes a blood meal and passes the trypomastigotes into the mammal bloodstream via its feces
2. trypomastigotes penetrate cells and transform into amastigotes 3. amastigotes multiply by binary fission 4. amastigotes rupture the cells and transform to trypomastigotes, which can infect other body cells 5. Triatomine bug takes a blood meal and ingests trypomastigotes 6. epimastigotes multiply in the vector's midgut 7. trypomastigotes in the hindgut ready to be excreted |
|
|
how does Trypanosoma cruzi infect carnivores?
|
- bites from the vector and trypomastigotes enter the wound
- dogs eat the vector and become infected - trypomastigotes in non-clotted blood are infectious |
|
|
why is Toxoplasma a problem especially in immunocompromised individuals?
|
Because the bradyzoite tissue cysts, although they do not cause an immune response when intact, will cause an immune response when ruptured. In immunocompromised individuals, the lack of an immune response will allow uncontrolled proliferation of bradyzoites.
|
|
|
What are the the five most common clinical signs of toxoplasmosis?
|
1. pneumonia
2. hepatitis 3. abortion 4. encephalitis 5. ocular disease |
|
|
In humans, what are five major risk factors for toxoplasmosis?
|
1. congenital infections
2. retinocorditis 3. AIDS (encephalitis) 4. immunosuppressed 5. organ transplant |
|
|
how can Toxoplasma in meat be killed? What specifically is being killed?
|
Freezing and cooking kills the tissue cysts
|
|
|
In human congenital toxoplasmosis, how do the risk of infection and the severity of the congenital defects change as the pregnancy proceeds.
|
as the pregnancy proceeds from 1st --> 3rd trimester:
- the risk of infection increases - the severity of congenital defects decreases |
|
|
What two conditions must be met for a mother to infect her fetus with Toxoplasma?
|
1. she must not have been previously exposed (no antibodies to the tachyzoites)
2. She must be infected after getting pregnant |
|
|
in the treatment of toxoplasmosis with medication, why must immunosuppressed individuals stay on the medication?
|
Because the medication only killls the tachyzoites. It will not kill the dormant bradyzoites in the tissue cysts.
|
|
|
How does age affect Toxoplasma in cats?
|
Young cats make more oocysts. Cats will eventually develop a strong immunity to the EE stages, and therefore shed less oocysts.
|
|
|
What are the major sites of toxoplasmosis in cats?
|
- Lungs
- Liver - Brain - other organs |
|
|
How does Toxoplasma gondii affect large animals
|
- usually asymptomatic
- abortions in sheep, goats, and pigs (not usually cattle) |
|
|
Which zoo animals are especially susceptible to toxoplasmosis?
|
- Australian marsupials
- Lemurs and other arboreal monkeys - Some birds |
|
|
What is the most obvious sign of Neospora canium infection in dogs?
|
Rigid hind-limb paralysis
|
|
|
What is the major difference between Toxoplasma and Neospora canium with regards to immune response?
|
Immune response to Neospora canium is poor, so recurrent infections are common. For example, multiple abortions in consecutive pregnancies will occur.
|
|
|
Which animals are particularly susceptible to Neospora canium and what diseases present?
|
- Dogs: neonatal disease, posterior paralysis, encephalitis, polyradiculoneuritis ("coonhound paralysis"), polymyocystitis
- Cattle: abortion (3-8 months) - Horses: congenital infection, abortion, CNS |
|
|
who is the definitive host for Neospora canium?
|
dogs
|
|
|
microscopically, how do Neospora tissue cysts differ from Toxoplasma tissue cysts?
|
Neospora tissue cysts have very thick walls
|
|
|
in Sarcocystis infections, where do the tissue cysts occur and what are they called?
|
They are in the muscle and called sarcocysts
|
|
|
How do the oocysts in Sarcocystis infections differ from Toxoplasma and Neospora?
|
They are excreted fully sporulated
|
|
|
What is the life cycle for Sarcocystis?
|
1. intermediate host eats sporulated oocyst
2. A first generation schizont is produced in the liver 3. merozoites disperse to many organs and produce second generation schzonts 4. merozoites migrate to muscle tissue and produce sarcocysts. 5. carnivore eats the muscle of the intermediate host 6. sarcocyst produces EE stages (microgamont, macrogamont, oocyst) 7. oocysts are excreted fully sporulated |
|
|
What are three major clinical signs of sarcocystosis?
|
- Abortion
- Systemic disease - Encephalitis |
|
|
Why are the brain, eye, and placenta especially good targets for protozoan infections?
|
Because they are "immunologically privileged" parts of the body, which means that the immune system is naturally suppressed in these regions
|
|
|
How does Sarcocystis affect large animals?
|
- usually asymptomatic
- prevalent in grazers and wild animals - occasional abortion - grossly visible cysts will cause carcass condemnation - S. neurona is an extremely dangerous species that causes EPM in horses |
|
|
What is the life cycle of Sarcocystis neurona and where do horses lie in this life cycle?
|
- Typical Sarcocyst carnivorous transmission between rodents, racoons, and the opossum (definitve host)
- Oocysts are eaten by the horse, which are accidental hosts - can cause EPM - horses are a dead-end host and the Sarcocystis will not spread (unless the opossum eats the horse's brain or spinal cord) |
|
|
What is EPM, its causative agent, and clinical signs?
|
Equine protozoal myloencephalitis
- caused by Sarcocystis neurona - severe neurological disease: ataxia, muscle weakness, muscle atrophy - should be considered as a rule-out in all horses with neurological diesase |
|
|
Why does Sarcocystis neurona infection only cause sporadic EPM in horses?
|
Because they have a high prevalence of serum antibodies.
|
|
|
How is an active EPM infection diagnosed? Why can't an antibody titer be used?
|
- a western blot of the CSF indicates active infection of Sarcocystic neurona
- titers can't be used because many horses have sufficient antibodies to eliminate the disease |
