Equine External Parasites

How much money is spent per year to control parasites in the horse industry?

$270 million

How much money is used to treat insect-borne diseases?

more than $150 million

What are the premise flies?

house fly

stable fly

What are the pasture flies?

face fly

horn fly

What is the common name for Tabanus spp.?

horse fly/deer fly

What are characteristics of Tabanus spp.?

they’re vigorous day time feeders, they find animals except in darkened buildings

ONLY FEMALES BITE

What species are affected by Tabanus spp.?

mainly cattle and horses sometimes humans

How long is the Tabanus spp. life cycle?

varies per species, from 70 days to 2 years

What damage can Tabanus spp. cause?

pain from bite (they introduce an anticoagulant)

frenzied behavior in order to escape flies

reduced condition

mechanical transmitters of disease (equine infectious anemia (EIA) AKA Coggin’s)

What is the common name for Stomoxys calcitrans?

stable fly/biting house fly

What are characteristics of Stomoxys calcitrans?

capable of flying more than 90 miles from their breeding site

visit animal only to feed, 80% of their time is away from animals

both sexes are vicious daytime biters

Simply what is the lifecycle of Stomoxys calcitrans?

complete cycle takes 12-60 days

flies live ~1 month

prefer shelter from the wind so they stay lower to the ground, suck blood from host once or twice daily preferring the legs or feet, or eats of swine and dogs.

female require several blood meals before eggs can be laid

orient themselves w their tail toward the ground

What damage can Stomoxys calcitrans cause?

flies need 3 minutes to feed

painful bites, blood loss; reduced milk production, feeding efficiency, and rate of gain

may transmit habronema

What is the common name for Haematobia irritans?

horn fly

What are characteristics of Haematobia irritans?

attack horses pastured near cattle

½ the size of stable/house flies

both sexes feed

What is the life cycle of Haematobia irritans?

ONLY LAID IN FRESH COW MANURE

total life cycle takes about 10-20 days

females lay 400-500 eggs in their lifetime

How can you control Haematobia irritans infestations?

ivomectin

What is the common name for Culicoides spp.?

biting midges or “no-see-ums”

What are characteristics of Culicoides spp.?

phlebotomus, only females feed

wet or aquatic habitants

What damage does Culicoides spp. cause?

painful bite, allergic dermatitis in horses w possible lesion formation

horses may lose their hair in the affected areas

How do you rid of Culicoides spp. infestation?

no effective measure for horses

for humans, no-see-um repellent (slight odor they dont like), mosquito blocker (“hide” ppl DEET)

What are characteristics of mosquitoes?

two-winged flies w sucking mouthparts

females suck blood males do not

attack all warm-blooded animals

What is the life cycle of mosquitoes?

aquatic: egg, larvae, pupae

terrestrial: adult

when adults emerge their first meal is nectar

females need blood meal to make eggs

What damage do mosquitoes cause?

spread disease like west niles (WNV) or encephalomyelitis (EEE,WEE,VEE)

How can mosquitoes be controlled?

removing/draining breeding sites

daily fogging

vaccinate

What is the common name for musca domestica?

house fly

What are characteristics of musca domestica

do not bite or feed blood, found inside stables

prefer to breed in manure

What damage do musca domestica cause?

can be vectors of disease and transmit bovine mastitis or pink eye

annoyance by feeding on muzzle, eyes and open wounds

intermediate host for habronema

How to control musca domestica infestation?

remove manure often in warm weather

chemical controls: larvicides, baits, sprays

What is the common name for calliphoridae?

blow fly

What is the common name for Cochliomyia hominivorax?

screw worm

How do calliphoridae larvae develop?

feeding on dead or living tissue

How are screw worm maggots different from other maggots

screw worms feed on live tissue

What is the sterile male method?

male pupae are harvested and irradiated with 6000 rad gamma rays sterilizing them. A factory in mexico produced up to 500,000,000 sterile flies a week

What sterile male method incident happened?

February 2003, a Cochliomyia hominivorax lab in mexico accidentally released 4 million fertile flies due to ineffective irradiation

What kind of lice is Bovicola equi?

chewing/biting

What kind of lice is Haematopinus asini?

sucking

What are characteristics of lice?

permanent parasites meaning they spend their entire life on the host

lice are host specific

What damage does lice cause?

heavy infestation in winter c/s:

anemia, poor appearance, loss of condition, stunted growth, uneasiness, hair loss, wounds/scabs

What is the lice cycle of biting lice?

feed on the skin causing itching irritation and hair loss

most prevalent on the head, mane, base of tail and shoulder

What is the life cycle of sucking lice?

can only live for 2-3 days off the host

normally seen in damaging numbers in the winter and be found anywhere in the body

How do you control lice infestation?

transferred from animal to animal by contact and contaminated bedding

check periodically for infestations and treat animals/premise

What are the two basic groups of horse mites?

mange and chigger

What is the common name for Chorioptes equi?

tail/hock mange

What are characteristics of Chorioptes equi?

puncture skin to feed off lymph fluid, survive on host for 3 weeks chewing skin debris and hair, around edges of oozing lesions

What is the life cycle of Chorioptes equi?

live on the host’s skin and feed on exfoliated skin cells, advanced infestations feed on healthy epidermis

THEY DO NOT BURROW

What are clinical signs of Chorioptes equi?

feet stamping

lesions on distal limbs, abdomen, groin, axilla

How do you get rid of a Chorioptes equi infestation?

transmits by host to host contact but also via grooming equipment, more evident during winter

treat w anthelmintics and antibiotics

What is the common name for Psoroptes equi?

scale and wet mange

What is the life cycle of Psoroptes equi?

very rare in horses

punctures the skin to suck lymph fluid, all life stages are around oozing lesions, can survive on the host for 2-3 weeks

What location are Psoroptes equi commonly found?

they produce lesions on thickly haired regions, but can spread over the entire body if untreated.

forelock, mane, base of tail, axillary region, under chin

What are clinical signs of Psoroptes equi?

inflammatory lesions that ooze fluid and form crusts, horses extremely pruritic

can be identified by skin scraping edges of active lesions

How do Psoroptes equi infestations occur?

late winter months when host animals have denser coats and tend to huddle in groups

How can Psoroptes equi be controlled?

ivermectin, topical eprinomectin

What is the common name for Sarcoptes scabei var equi?

dry mange

What are characteristics of Sarcoptes scabei var equi?

most severe type of mange in horses, they burrow beneath the skin

What is the life cycle for Sarcoptes scabei var equi?

females tunnel after mating 10-30 days after they hatch, male dies after mating, female dies after laying eggs in tunnel

the mites secrete irritating toxin in the tunnel causing extreme reaction and itching. The host reaction causes the skin to come off infested areas

How do Sarcoptes scabei var equi cause infestation?

they are contagious and all animals must be treated to get rid of it. ZOONOTIC

What is the common name for Demodectic mites?

follicular mite

What are characteristics of Demodectic mites?

all stages are found within the hair follicle and sebaceous glands. mites cause nodular lesions in the skin.

face, neck, shoulders

How do you control Demodectic mites infestations?

difficult because of their depth in the skin

ivermectin, lime sulfur dip, organophosphates

What is the common name of Chigger mite?

red bug

What are characteristics of chigger mites?

suck tissue fluid, injects digestive enzyme into wound and suck up digested tissue.

humans are accidental host and chigger dies w/i 24-72 hours bc humans are immune to bite and they can not get nourishment

What is the life cycle of a chigger?

eggs are laid on soil and hatch into larval 6-legged parasitic “chigger”. they attach to a host and feed for 3-4 days. they then fall off and molt to not parasitic nymphs and adults. adult chiggers do not feed on animals.

What damage do chiggers cause?

itching and red welts. chiggers dont transmit disease

How can you prevent chigger mite infestation?

wear long clothes that cover body. insect repellent (DEETs) permethrins for horses

What are characteristics of ticks?

hard ticks and spinose ear ticks

Who is a vector for babesiosis in horses?

hard ticks (dermacentor)

What can spinose ear ticks cause?

severe damage to ear and inner ear

What are characteristics of dermacentor?

females feed on blood and lymph, male will feed but not fully engorge

What damage can dermacentor cause?

disease transmission: EIA, equine piroplasmosis (babesia)

How can you control dermacentor infestation?

insecticides, spot-on, spray, dips

What is the common name for Otobius megnini?

spinose ear ticks