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72 Cards in this Set
- Front
- Back
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What are the 5 major groups of parasites?
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- protists
-nematodes -trematodes -cestodes -arthropods |
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What is a nematode?
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a "round worm"
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What is a trematode?
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a "fluke" (flat worm)
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What is a cestode?
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a "tape worm" (flat worm)
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Of the word "Arthropod", what does "arthros" and "podos" mean?
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"Arthros" = joint
"Podos" = foot |
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What are the 3 classifications of arthropods?
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- Crustateans
- Insects -Arachnids |
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What are the features which are used to class the 3 classes of arthropods?
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Number of legs
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Which class of Arthropod has 4 pairs of legs?
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Arachnids
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How many pairs of legs does a Crustacean have?
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Five
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Which class of Arthropod has 3 pairs of legs?
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Insects
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What are the features of Arthropods that hold veterinary significance?
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- The exoskeleton (cuticle)
- The muscle system (attached to exoskeleton) - The circulatory system (open, blood is free in haemocoel) |
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What is the basic outline of an Arthropod digestive system?
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mouth --> intestine --> rectum
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What is the most significant feature of an Arthropod's digestive system, from a veterinary POV?
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The Salivary glands
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Why are the salivary glands of an Arthropod significant from a veterinary POV?
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Because diseases can be transmitted from Arthropod to host via the salivary glands (when they bite/eat/feed on host)
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What part of the Arthropod is the most common target of drugs?
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The nervous system
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What are the two types of respiratory systems on arthropods?
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- gills in aquatic arthropods
- tracheal system (holes in the exoskeleton) in terrestrial arthropods |
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What is the simple method by which one could kill an arthropod by targeting its respiratory system?
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Cover it will oil
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What are the two types of parasitism?
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- Ectoparasites (lives inside body)
- External Parasites (lives outside body) |
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What is an" obligate parasite"?
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A parasite that MUST have a host (eg: fleas)
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What is a "facultative parasite"?
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A parasite that can survive without a host (eg: flies)
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What is a "Permanent Parasite"?
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A parasite that must be on a host at ALL TIMES (eg: lice)
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What is an "Intermittent Parasite"?
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A parasite which visits its host(s) periodically (eg: mosquetos - only females feed on hosts, males eat nector)
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In reference to an Arthropod's life cycle, what is meant by the term "mault"?
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To shed the outer layer of the body
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In reference to an Arthropod's life cycle, what is meant by the term "instar"?
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The stage in the insects life between two maults.
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Define Metamorphoses:
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The name given to the changes that take place during the insect's life as it turns from an immature form to an adult.
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What is the most common form of pathogenicity of arthropods:
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That they will act as vectors for viruses, bacteria or other parasites.
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What are the 3 major mechanisms of chemical control of arthropods?
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1) repellents
2) Chemicals acting on the nervous system 3) Growth Regulators |
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Name the 4 most common types of Repellents used:
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- DEET
- dipropyl isocinchomeronate - piperonyl butoxide - citronella |
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Name the 3 types of Chemicals used to act on the nervous system:
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- DDT
- Lindane (gamma benzene hexachloride - Dieldrin, Endrin |
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What were Chlorinated Hydrocarbons used for, and why were they banned?
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-Used as an effective insecticide for mass field spraying
-work on the nervous system to cause paralysis - It does not break down, so accumulation can occur up food chains. |
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What is the method of organophosphates in acting on the nervous system of an Arthropod?
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Blocks acetylcholine esterase (Ach) therefore prevents neural messages from being transferred across the synapse = paralysis
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Why are organophosphates commonly used?
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- effective method of paralysis
- breaks down quickly so cannot accumulate up the food chain and harm non-target organisms - can be treated with Atropine to reverse (if necessary) |
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What are the two administration methods of organophosphates?
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- topical (body surface)
-oral |
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How do Carbamates act as an insecticide?
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via similar action to organophosphate - interfering with the nervous system and causing paralysis.
(lasts 4-6 weeks, longer than organophosphates) |
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What is the most common use of carbamates as an insecticide and why?
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Flea control - because it can persist for 4-6 weeks.
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How do Formamidines cause paralysis in arthropods?
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by inhibiting mon-amine oxidase
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What is "Amitraz" an example of, and what is it used for?
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- example of a Formamidine
- used for treatment of ticks and demodentric mange in cattle |
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Pyrethroids cause paralysis in arthropods. What is their method of action?
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Blocks sodium channels of axons in nervous cells so that action potentials cannot take place, therefore a nervous message cannot be sent.
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What is the difference between "Pyrethroid" and "Pyrethrin"?
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Pyrethoids is taken from Pyrethin and concerntrated
- Pyrethin is originally derived from the chrysanthemum flowers. |
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Is the toxicity of Pyrethoids high or low to vertebrates?
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low - except to fish.
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How long do Pyrethroids last for?
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only 24 hours
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How would you administer a Pyrethoid?
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via topical (surface) administration
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What do Macrocyclic lactones do, and how do they work?
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- cause paralysis
- act on glutamate-gated chloride channels to disrupt ability to produce action potentials |
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What types of Parasites are Macrocyclic lactones highly effective against?
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Arthropods and nematodes
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Neo-nicotinoids (and others) cause paralysis. How?
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by blocking receptors
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What is a common product which Fibronil (a Neo-nicotinoid) is found in?
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Frontline - flea control
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How are Neo-nicotinoids admmistered, and what is their toxicity to vertebrates?
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- topical administration
- non-toxic |
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Imidacloprid:
What class of chemicals that cause paralysis does it belong to? |
Neo-nicotinoids
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Imidacloprid:
How does it cause paralysis? |
By blocking nicotinic receptors (found in "Advantage" products)
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Imidacloprid:
When applied topically, how does it work to treat ectoparasites? |
By distributing through the skin and not entering the tissue/ blood beneath.
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Ivermectin:
What class of chemical does it belong to? |
Macrocyclic lactones
- acts on glutamate-gated chloride channels |
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Ivermectin:
When applied topically, how is it distributed? |
Through the dermis and into the blood.
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How do Growth Regulators work?
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By interfering with growth, moulting, and egg laying
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How are Growth Regulators administered, and what is their toxicity?
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- oral or topical
- low toxicity |
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Why do Growth regulators work (their mechanism)?
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Because they are analogues of insect growth hormones, therefore mimic the hormones and can interfere with their actions.
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Why are Growth Regulators used less than Repellents or chemicals that interfere with the nervous system?
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Because they do not kill the arthropods immediately but instead work to inhibit their reproduction - therefore a population controller.
- not popular as public want to see "instant kill" |
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What are the 3 subclasses of Parasitic Crustaceans?
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- Copepoda (ecto-parasites of fish)
- Isopoda (ecto-parasites of fish) - Pentastomida (internal parasites of reptiles, birds, mammals) |
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What crustacean sub class does "Cyclops" belong to?
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Copepoda
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What is a common Crustacean Copepoda that is common on aquarium fish?
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Lernea sp. (anchor worm)
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What Custacean subclass does "Ourozuektes owenii" belong to?
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Isopoda
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Where is the Crustacean Isopoda "Ourozuektes owenii" found in marine fish?
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within the body cavity
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What Crustacean sub-cass does "Conodophilus imbracatus belong to?
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Isopoda
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Why is Conodophilus imbricatus" called "tongue bitter"?
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because it consumes the fish's tongue and then latches on and takes the place of the tongue, acting like a tongue.
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Where are the Crustacean sub-class "Pentastomida" mainly found?
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In the respiratory system of birds, mammals, and reptiles
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Asides from being a sub-class of the Crustacean group, what do Pentastomida look more like?
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Worms, with a hard exterior
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What is the structure of the Pentastomida's "head" (Crustacean group)?
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two hooks (legs) on either side of mouth
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Where is the Linguatula serrata (Crustacean - Pentastomida) found?
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found in the nasal cavity of dogs
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The Linguatula serata ("tongue worm") (Crustacean - Pentastomida) has an indirect life cycle. What are the brief steps of this life cycle?
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- adult in the nasal cavity of the dog
- eggs laid and travels in mucous down nasopharynx to pharynx and swallowed - eggs passed out in faeces - eggs distributed into soil - eggs and soil particles eaten by grazing sheep / rabbits - lava activated in sheep/rabbits and move into flesh - raw flesh containing lava of sheep / rabbits eaten by dog - lava matures and crawls up stomach, oesophagus and pharynx of dog to nasal cavity. - life cycle repeats |
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What are the clinical signs of "Linguatula serrata" (Crustacian - Pentastomida):
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nasal discharge and severe irritation
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How would you diagnose the presence of Liguatula serrata in a dog?
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finding the eggs in faeces
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What drug would you administer for the treatment of Linguatula serrata?
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ivermectin
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What is a key feature of a Pentastome of reptiles(Crustacean) indirect life cycle?
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They use small mammals or other arthropods as intermediate hosts
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