Ectoparasite Integrated Vet Med

What are some features of the soft tick life cycle?

1-2 nymphal stages

feed fast, repeatedly

often have multiple hosts

will oviposit many times (hundreds at a time)

What is the one soft tick that is a one host tick?

Otobius megnini

What are some features of the hard tick life cycle?

1 nymphal stage

females eat once slowly, males eat quickly/repeatedly

1-3 host ticks

oviposit thousands at once

What habitat preference do soft ticks have?

nidicolous - like to stay in barrow/nest

tolerate arid environments

What habitat preference do hard ticks have?

non-nidicolous (wander)

prefer humid environments

What is the life cycle of a 1 host tick?

larvae feed on host 1 and molt to nymph which feeds on same host and finally molts to adult the feeds/mates on host 1 and dies off host

What species of ticks can transmit Babesiosis?

Rhipicephalus microplus (southern cattle tick) and Rhipicephalus annulatus (cattle tick)

transmit Babesia bovis, Babesia bigmina, and Anaplasma marginale

What is Babesiosis?

cattle fever

signs include fever, anemia, weight loss, and death

first tick borne dz ever described

What are some pathological signs of bovine babesiosis?

pink brain - due to red cells clumping together from distention of blood vessels with parasitized erythrocytes

icterus due to hemolysis

splenomegaly

What is Dermacentor albipictus?

winter tick (are active late fall, winter, early spring)

1 host tick of moose (horses, cattle)

causes hair/blood loss

What is the life cycle of a 2 host tick?

larvae feed on host 1 and molt into nymph that feeds on host 1

nymph falls off and molts to adult that feeds/mates on host 2 and drops off

What is the life cycle of a 3 host tick?

larvae feed on host 1 and drop off to molt into nymph

nymph feeds on host 2 and drops off to molt into adult

adult feeds/mates on host 3 and dies off host

What are some genera that are soft ticks?

Argas

Ornithodoros

Otobius

What are some genera that are hard ticks?

Ixodes

Ambylomma

Dermacentor

Rhipicephalus

What are Ornithodoros?

parasitizes mainly mammals

have leathery cuticle with rounder body margin

can transmit epizootic bovine abortion

What is epizootic bovine abortion?

foothill abortion

transmitted by Ornithodoros coriaceus

caused by pajaroellobacter abortibovis

causes late term abortion, chronic fetal dz, weak calves

What are some examples of direct tick dz?

tick bites

can cause irritation (tick worry), anemia, secondary infection

What ticks cause toxicosis (tick paralysis)?

females

Dermacentor varaiabilis (american dog tick)

Dermacentor andersoni (rocky mountain wood tick)

Ambylomma americanum (lone star tick)

Ixodes sacpularis (black legged tick, deer tick)

What are some indirect tick dz?

transmission of pathogens (bacteria, protozoa, viruses)

What makes ticks good vectors?

blood feeders, wide host range, long lived, few predators, high repro potential

vector competency

pathogen can be maintained in tick population

What is rickettsia rickettsii?

causative agent of rocky mountain spotted fever

spread by dermacentor (in majority of US)

causes vasculitis, fibrinous thrombosus in liver, foamy fluid in trachea, brain hemorrhage

signs incllude bilateral nasal discharge, nystagmus, ataxia, drooling, wheezing

What is the major vector of RMSF in Arizona?

Rhipicephalus sanguineus (brown dog tick)

most common tick throughout arizona

hides in walls, cracks, carpet, crevice

What is bovine anaplasmosis?

hemolytic anemia, fever, depression, anorexia

survivors remain carriers

50% mortality in adults

What is the main vector and causative agent of bovine anaplasmosis?

vector - Dermacentor andersoni (or fomites/biting flies)

agent - Anaplasma marginale (mainly), Anaplasma centrale (mild)

What is American canine hepatozoonosis?

Hepatozoon americanum (protozoa)

causes fever, weakness, chronic weight loss, anemia, depression, muscle pain

will see onion skin cysts or gamont in WBC

What is the vector and transmission of Hepatozoon americanum?

vector - Ambylomma maculatum

must ingest infected tick or paratenic host

hosts include domestic dogs, coyotes, bobcats, carnivores

What is Cytauxzoon felis?

cytauxzoonosis

protozoa

2 phases

tissue phase - schizonts in macrophages in blood vessels

erythrocytic phase - merozoites in RBC (causes hemolysis)

sympsomts in clude depression, anemia, leukopenia, thrombocytopenia

What are the vectors and transmission of Cytauxzoon felis?

vectors - Ambylomma americanum, Dermacentor variabilis

from tick biting

reservoir = bobcat

What is tick paralysis?

salivary neurotoxin from engorged female tick inhibits ACh release from axon terminal

acute ataxia prgresses to ascending paralysis

early tx - complete recovery with tick removal but untreated causes resp. failure and death

What is Gastrophilus intestinalis?

equine stomach botfly with predilection for non-glandular stomach

has semilunar bot spiracle

What is the life cycle of Gasterophilus intestinalis?

eggs to hairshafts of forelegs/shoulders then pop out and are ingested

will lie in margo plicatus for a year until adult flies emerge (3-9 wks)

What is gasterophilus nasalis?

botfly with predilection for glandular portion of stomach

semilunar spiracle

What botfly genera does this spiracle belong to?

Gasterphillinae

What is Oestrus ovis?

sheep nasal botfly

tx with ivermectin

causes false gid (resides in nasal cavity but sometimes larvae wander into brain)

has button/D shaped spiracle

What genera of botfly does this spiracle belong to?

Oestrinae

What are Cuterebra?

botflies that mainly parasitize rabies but also rodents/cats/dogs

migrate to subcutis, larvae in cats/dogs may migrate to other organs/brain

has brain-like appearance to spiracles

What genera of botfly does this spiracle belong to?

Hypoderma

What genera of botfly does this spiracle belong to?

Cuterebra

What can cause feline ischemic encephalopathy or multifocal cerebral hemorrhage?

cuterebra due to larval migration

What is leishmaniosis?

common in dogs and more rare in cats

transmited by Lutzomyia/Phlebotomus sand lfies

causes visceral leishmaniosis, dry itchy skin

What are the vectors for heartworm?

Anaphaeles, Aedes, Culex (mosquitoes)

only about 70 species capable of transmitting HW

What is the life cycle of Dirofilaria immitis in dogs?

mosquitoes ingest microfilaria in blood meal

develop into L3 in mosquito and migrate to mouth parts

L3 then spread to dog via mosquito bite and reside in skin

develop into L4 within muscles/SQ tissue

molt into immature adutls and migrate to circulatory system/enter pulmonary arteries and right heart

adults then live for 5-7 yrs and females produce microfilariae

What are some differences of HW in cats?

cats low susceptibility and adult worms live shorter (2-4 yr)

infect fewer than 6 worms and single sex infections are more common

microfilaremia uncommon and only lasts about month

lung is primary organ of concern (dogs is heart)

What is Ctenocephalides felis?

feline flea

wide host range but prefer cats

most common ectoparasite of dogs/cats in NA

spine 1 and 2 of comb are approximately equal in length

sloped head

What is Ctenocephalides canis?

dog flea

narrower host range (mostly dogs)

less common

spine 1 shorter than spine 2

rounder head

What is Demodex canis?

host specific to dogs and causes alopecia/erythema/ulcers crusts

live in hair follicles

What is Sarcoptes scabiei?

mites

strong hypersensitivities in foxes/cyototes that lead to thick crusts and severe pruritius

embed in skin