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116 Cards in this Set
- Front
- Back
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How are lice transmitted?
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Animal to animal, 99% of lice are on the host
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What are the 2 types of lice?
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Mallophaga: biting lice
Anoplura: sucking lice |
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What is the difference b/w a nymph and a larva?
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Nymphs have a morphology similar to that of the adult, larvae do no (think of a maggot compared to a fly)
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What is hemimetabolous?
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Applies to the life cycle of a typical louse, characterized by a succession of nymphal stages similar to that of the adult
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True or false. Lice use pupa in their life cycle.
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False, life cycle of lice are hemimetabolous and do not include pupa or cocoons.
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Compare and contrast lice & fleas.
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Lice:
-Obligate parasites -99% are on host, not environment -Treatment is easier because can just do all animals -Close association with host -Vast majority Very host specific Fleas: -90% are in environment -Not host specific -Not closely associated with host -Much harder to treat bc in environment |
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What is the morphology of lice?
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Dorsal-ventrally flattened
Tarsal claws for clinging Reduce or no eyes Wingless |
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What is the basic life cycle of lice?
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Adult---> eggs (nits)---> nymph 1---> nymph 2-----> nymph 3--> adult
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How can you easily distinguish b/w sucking lice and biting lice?
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Biting lice: head is bigger than thorax (needs room for all those teeth!)
Sucking lice: head is smaller than thorax |
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Trichodentes is the intermediate host/vector for what parasite?
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Dipylidium caninum -fleas & biting lice
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True or false. Sheep are susceptible to face lice, body lice and foot lice, but only the face lice presents a serious problem.
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False, only the body louse, Bovicola ovis, is problematic
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Why do some flocks remain infested with Bovicola ovis?
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Many populations are resistant to pyrethroid lousicides but are still used.
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What causes deer hair-loss syndrome?
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Mallophaga (biting lice)
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What are 3 species of mallophaga?
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1) Trichodentes canis
2) Bovicola species 3) Felicola subrostratus |
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What dogs commonly have Trichodentes infection and where are they located on the body?
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Malnourished dogs will have them all over the body
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What can you do to prevent Trichodentes canis infections?
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Add vitamin B to the diet
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What are the clinical signs of Trichodentes canis infection?
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Severe itching
Loss of sleep |
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What is the treatment for Trichodentes canis?
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Insecticides
Ivermectin products |
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What animals are infested by Felicola subrostratus?
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Cat louse
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What is the clinical presentation of a cat w/ Felicola subrostratus infestation?
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Scruffy, dry haircoat
Alopecia Pruritis Anemia |
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How do you control Felicola subrostratus infestations?
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Pyrethrin sprays or powders
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Why do pyrethrin sprays or powders have to be repeated in 10-14 days to control Felicola subrostratus infections?
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Because the nits aren't killed
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How do you prevent Felicola subrostratus infestations?
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Frontline (Fipronil)
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What is the geographical distribution of Bovicola bovis?
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World wide
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What cattle are infested with Bovicola bovis?
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Any age or breed
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What is the host range of Bovicola bovis?
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Infects only cattle
Lice=very host specific! |
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What causes the irritation due to Bovicola bovis infestations?
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Their claws and their sucking parts
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Where are Bovicola bovis eggs found?
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Attached to hairs close to the skin
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How long does it take Bovicola eggs to hatch?
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~8 days
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How many nymphal instars are in the bovicola life cycle? How long does it take nymphs to develop into adults
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3 nymph instars
3 weeks |
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How long do adult bovicola live?
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1.5 months
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What is the seasonality involved with bovicola ovis infestations?
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Light in the summer, heavy in late winter-early spring
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What are the biggest issues pertaining to bovicola ovis infestations?
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Loss of production
Treatment costs |
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Why are mallophaga so pathogenic to local deer?
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Because mallophaga is an introduced pathogen to local deer
-Asiatic deers tolerate infestation much better |
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What are 2 common generas of sucking lice?
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1) Haematopinus spp.
2) Linognathus spp. |
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How long do Bovicola survive off the host?
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NOT long
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What species do Haematopinus spp. infest? What specie is it of concern in?
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Swine=important
Cattle Horses |
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The size of Haematopinus is very _______.
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Large
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How long is the life cycle of Haematopinus?
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1 month
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How long do Haematopinus survive off the host?
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3 days
-Biting lice don't survive off host |
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What is the biggest problem related to haematopinus infestations?
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Loss of production in swine
-Transmit swine pox? |
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What are the 2 animals affected by linognathus species?
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Sheep & cattle
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What are the clinical signs of Linognathus infestation?
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Anemia, weight loss, irritation
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What kind of damage to biting lice do to poultry that is different from other species?
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Cause feather damage because feed directly on feathers
-Feathers appear moth eaten |
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How many legs do mites have?
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3 pairs
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How many legs do ticks have?
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Adults=4 pairs
Larvae=3 pairs |
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How many body segments do Acari (ticks) have?
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Segments are fused
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How are mites & ticks different?
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Mites:
-Smaller -Diversity of life cycles Ticks: -Larger -Well developed hypostome -Parasitic |
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How are the mouthparts of ticks & mites different?
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Mites:
-Small -Lymph & secreta Ticks: -Large -Blood & lymph |
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What cestode uses a mite as its intermediate host?
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Monezia & anoplocephala
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What are the 4 important pathologies associated with tick infestations?
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1) Anemia
2) Paralysis 3) Dermatosis 4) Otoacariasis |
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What causes dermatosis associated with tick infestations?
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Mechanical irritation
Tissue reaction to saliva Secondary infections |
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What pathogens are transmitted by ticks?
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Apicomplexa
Filaroid nematodes Bacteria Viruses |
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What are the 3 components of tick mouth parts? What are their functions?
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1) Pedipalps: folds skin of host
2) Chelicerca: cuts host skin 3) Hypostome: inserted into host |
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What is secreted when a tick feeds?
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Saliva & compounds:
-Anticoagulant--> increases blood flow -Immunosuppressors |
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What do ticks regurgitate at the wound? Why is this important?
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Water, allows for pathogen transmission
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What is required for pathogen transmission to successfully occur when a tick feeds?
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Attached for at least 24 hours
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What causes tick paralysis?
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A neurotoxin produced by salivary gland
-Usually occurs w/ prolonged attachment |
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True or false. Tick paralysis is not a lethal condition.
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False, can cause respiratory paralysis
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True or false. Removal of ticks reverses tick paralysis.
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True
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Tick paralysis is an issue in what animals?
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Cats, dogs, humans, livestock
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What are the 2 classes of ticks?
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Hard (Ixodidae)
Soft ticks (Argasidae) |
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What is the inflexible dorsum of hard ticks called?
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Scutum
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Compare soft & hard ticks.
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Hard:
-Inflexible dorsum-scutum -Mouth parts visible dorsally -Longer association w/ host Soft: -No scutum -Mouth parts not visible dorsally -Shorter association -Typically in drier areas |
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What sex of ticks usually engorges? What happens to the morphology of the tick when engorged?
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Female, body gets larger but scutum stays the same size
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Are male or female Ixodidae larger?
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Female
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During what stage of a hard tick's life cycle are they parasitic?
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All stages
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How do you classify the life cycle of a tick?
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Based on number of hosts involved e.g. 3 host life cycle
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What is the life cycle of Ixodidae?
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Eggs hatch---> larva (6 legs)
Larva feeds 2 days--> nymph (8 legs) Nymph feeds 3 days--> adult Adult feeds 1 wk----> lays eggs -Leaves host between all stages! |
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What is different about the way that lice and ticks lay eggs?
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Ticks leave the host to lay eggs and lice do not
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How do ticks find a host?
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Questing
Crawl up bush or grass Extend forelegs Wait for host Cues: CO2, movement, heat |
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What ticks should come to mind for a one host tick?
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Cattle ticks such as Boophilus
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What are the 3 routes of pathogen transmission in ticks?
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1) Transstadial: b/w different stages of life cycle
2) Transovarial: adult to eggs 3) Intrastadial: b/w same stage |
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What would you call transmission if a nymph is inoculated with a pathogen from a deer then molts and passes it to a human?
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Transstadial
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What are the 4 hard ticks relevant to this exam?
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1) Ixodes
2) Dermacentor 3) Rhipicephalus 4) Rhipicephalus spp. boophilus |
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What is the genus and specie of the Western black legged tick?
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Ixodes pacificus
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What is the vector Lymes disease?
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Ixodes pacificus
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What is the leading arthropod disease in the US?
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Lymes disease
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What is the geographic hot spot for Ixodes pacificus?
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North East coast
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What is a common reservoir of Ixodes pacificus? Why?
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Lizards, because incompetent for Borrelia burgdorferi spirochetes
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What is the host range for Ixodes pacificus?
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Pretty general, common in dogs
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What type of life cycle do Ixodes pacificus have?
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3 host life cycle
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How are pathogens transmitted in Ixodes pacificus?
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Transstadial transmission
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How long must Ixodes pacificus feed to transmit pathogens?
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24 hours, optimal is 48-72 hours
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What is the vector for Rocky Mountain Spotted Fever?
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Dermacentor spp.
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True or false. Ixodes are sexually dimorphic.
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False, Dermacentor are sexually dimorphic
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What type of life cycle do most Dermacentor species have?
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3 host
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What is an additional structure seen on the caudal aspect of Dermacentors?
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Festoons
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How can you tell the difference b/w an Ixodes and Dermacentor tick?
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-Dermacentors have an anal groove that is concave under the anus and Ixodes have an anal groove that makes an arc over the anus
Dermacentor=Smile Ixodes=Frown -Ixodes have a separate head, dermacentor does not |
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How can you tell the difference between a male and female dermacentor?
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Males: ornate shield extends whole length of body
Females: ornate shield doesn't extend length of body |
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How do you identify Rhipicephalus species?
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Basis capituli (Darth vader's helmet)
Don't have long palates like Ixodes Festoons & spurs at base of capituli Adanal plates are very distinct |
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What animals are infested by Rhipicephalus sanguines?
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Mammals, reptiles, birds
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What is the genus and species of the brown dog tick?
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Rhipicephalus sanguines
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What is the geographic distribution of Rhipicephalus sanguines?
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Cosmopolitan -common in kennels
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What is the life cycle of the brown dog tick?
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3 host-all dogs so can be indoor life cycle!!
-Remember leave host b.w each stage |
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What is unique about Rhipicephalus sanguines?
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One of few indoor ticks
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Where do Rhipicephalus sanguines like to feed?
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Between the toes
Behind the neck In the ear |
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Where do Rhipicephalus sanguines lay eggs?
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In animal bedding & crevices
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Why have Rhipicephalus sanguines been demographically spreading?
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B/c they are warm climate ticks and heating systems have provided year round warm environments
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How do Rhipicephalus transmit pathogens?
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Transovarial
e.g. how babesia is transmitted -Ixodes pacificus=transstadial |
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What tick has a one host life cycle?
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Rhipicephalus spp. boophilus
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Why are dips used to treat Boophlus microplus and Boophilus annulatus infestations?
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Very small & dipping is very efficient bc one host tick
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Since boophilus is so easy to treat, why is it still an issue?
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White tailed deer can get the same boophilus species as cattle
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What is the vector of babesia?
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Boophilus annulatus
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What is the most important tick of livestock in tropics and subtropics but has been eradicated from the southern US?
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Boophilus annulatus-transmits babesia & anaplasma marginales
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How are Rhipicephalus spp. boophilus transmitted b/w animals?
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Very small and transported with host so spread when host makes contact
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What animals are infested by Boophilus species?
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Mainly cattle, but all livestock
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What are the 2 species of boophilus of importance in cattle?
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Boophilus microplus
Boophilus annulatus |
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Why is it easier to control boophilus infestations than tick problems?
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1 host!
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What is an effective treatment of boophilus?
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Dips
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Unfed boophilus ticks die in _____ days.
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65 days
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What is the general life cycle of boophilus?
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Adult on cattle, leaves host to lay eggs
Eggs--> larva---> host----> leaves host---> nymph---> host---> leave host--> adult One host tick |
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Why are cattle quarantined when coming from Mexico & south of border?
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To check for Boophilus annulatus which transmits babesia
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Compare the integument, life cycle, scutum and engorgement of hard & soft ticks.
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Hard ticks
-Hard integument -usually 3 hosts -1 nymphal stage -Scutum=sexual dimorphism -Engorgement is slow Soft: -Soft integument -Many hosts -2-8 nymphal stages -No scutum -Engorgement is fast (min-hrs) |
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True or false. Hard ticks have a longer association with the host than soft ticks.
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True
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How long do soft ticks survive without feeding?
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years
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