Bovine EctoparasitesDr. Dipa Brahmbhatt MPH DVM

Chapter 13

Bovine Ectoparasites• Limit production• Disease• Season:

– spring and summer – SE Texas's all year-round

• Phylum Arthropoda– Flies: Class: Insecta and

Order: Diptera – Ticks, mites: Class:

Arachnida ; Order: Ixodida

Heartwater ticks shown feeding on a cow

Bovine Ectoparasites - Taxonomy• Biting Flies: piercing mouthparts adapted for

blood sucking– Horn fly: Siphona (Haematobia) irritans– Stable Fly: Stomoxys Calcitrans– Horse (Tabanus sp.) and Deer Flies

(Chrysops sp.)– Screw worm fly: Cochliomyia

hominivorax– Gnats: Simulium and Culicoides

• Non-biting Flies– Face fly: Musca autumnalis

• Myiasis– Common cattle grub : Hypoderma

lineatum– Northern cattle grub : Hypoderma

bovis– Screworm: Cochliomyia hominivorax

• Lice• Chewing lice: Damalinia (Bovicola)

bovis – Sucking lice:

• longnosed cattle louse: Linognathus vituli

• shortnosed cattle louse: Haematopinus eurysternus

• Mites• Sarcoptes• Chorioptes• Psoroptes• Demodex bovis

• Mosquitoes• Ticks

Flies

•1 pair of wings•complete metamorphosis•~ 20 families of flies are of veterinary importance

House FlyCREDITS: J. F. Butler, University of Florida

Flies

Comparison of the horn fly to the stable fly, house fly, and face fly. Photo: Photo: John B. Campbell, University of Nebraska-Lincoln

Face fly: Musca autumnalis:

Horn Fly: Siphona (Haematobia) irritans

• Serious pests in TX • C.S: pain, irritation,

weight loss, low milk production, +/- open sores; secondary infections

• pierces the skin to blood feed

• persistent biter.

• Horn fly: greatest economic loss in US cattle

Horn flies congregate along the back and sides of cattle: SMALL AVID FEEDERS

Horn Fly: Siphona (Haematobia) irritans

• Lifecycle: 10 – 14 days– Eggs: laid in fresh (~ 10 min.

of dropping) manure. – Larvae: hatch ~18 hours and

feed on the dung > through 3 stages in 3 - 5 days.

– Pupal stage: lasts 3 to 5 days > adults which emerge have a preoviposition period of 3 days.

– Mating on the host• females can lay about

200 eggs in their lifetime

Tx: pyrethroid or organophosphate impregnated ear-tags and pour on’s (ivermectin): General for all ectoparasites

Stable Flies: Stomoxys calcitrans

• mechanical transmitters – anthrax – anaplasmosis

• Like house fly but the bayonet-like mouthparts of the differentiate it from the house fly.

• both sexes: biters. • C.S: irritation, lethargy

(blood loss in severe cases); bite wounds and secondary infections

• Tx: pour on’s sprays, remove feces and spoiled hay and grain

SMALL AVID FEEDERS

Horse (Tabanus sp.) and Deer Flies (Chrysops sp.)

Deer Flies (Chrysops spp.)

BOTH:•Only females bite.

•Daytime feeders: vicious biters.

Horse (Tabanus spp.)

• painful bites: stampedes• Transmit: Anaplasmosis, tularemia,anthrax

Gnats

• Simulium and Culicoides are both small gnats that have painful bites.

Culicoides

Face Fly: Musca autumnalis

• Feeds on tears, saliva and mucus.

• Annoying• Mechanical carries:

– Moraxella bovis– IBR– Thelazia spp

(eyeworms)

Myiasis: infestation of vertebrates by dipteran larvae (maggots)

Myiasis• U.S: Cattle warbles

– common cattle grub: Hypoderma lineatum

• LC: eggs – hair of cattle > maggots – skin > esophageal > pupa

– northern cattle grub: Hypoderma bovis

• LC: eggs – hair of cattle > maggots – skin > spinal cord > pupa

• Lifecycle: 10-12 months• Clinical signs

– damage - tissues and hide, reduction of weight gain

TX: before esophagus/ spinal cord > death: Sprays and dips using coumaphos or

phosmet, Pour-on formulations of famphur, fenthion, ivermectin, and

phosmet

Heel flies

Myiasis• Screwworm: Cochliomyia

hominivorax • LC: 3 weeks: Larvae > fly will bore

into live tissue maturing • Very pathogenic and high

mortality– feeds exclusively on live flesh

• Eradicated in US in 1966: introduced sterile males– REPORTABLE: cost producers

$75 million if back in US

LICE – LOUSE: Pediculosis

• Entire lifecycle on host• Transmitted: direct contact

– introduction of carrier animals

LOUSE

LOUSE: Mallophaga

• Chewing lice: order Mallophaga– Little red louse: Damalinia

(Bovicola) bovis

• LC: 4 wks.• Fall and winter:

brisket/leg/in between legs

• C.S: pruritus, unthrifty appearance and a rough coat

Damalinia bovis, male. Courtesy of Dr. Dietrich Barth, Merial

LOUSE: Anoplura• Sucking lice: order Anoplura

– longnosed cattle louse: Linognathus vituli

– shortnosed cattle louse: Haematopinus eurysternus

• Head/ neck/ brisket: winter to early spring

• LC: 4 wks. • C.S: pruritus, unthrifty

appearance and a rough coat, anemia (rare severe infestation)

Linognathus vituli, female. Courtesy of Dr. Dietrich Barth, Merial

Haematopinus eurysternus, female. Courtesy of Dr. Dietrich Barth, Merial

MITES: MANGE

Sarcoptes, Chorioptes, and Psoroptes can be easily differentiated by leg stalk characteristic and mouthparts. Speciation is more difficult and usually requires an expert acarologist.

Sarcoptes Chorioptes Psoroptes

Mange Mites• Sarcoptes scabiel• Transmission: contagious,

spread by direct contact or indirectly by fomites.

• LC: 3 weeks• CS: head, neck, and

shoulders: pruritus is intense, papules develop into crusts

• Diagnosis: deep skin scrapings

• Zoonotic and reportable Sarcoptes scabiei var bovis, female. Courtesy of Dr. Dietrich Barth, Merial

Mange Mites

• Psoroptes spp (most damaging)

• LC: 3 wks. • C.S.: Intense pruritus,

lichenification, secondary bacterial infections, weight loss, dec. milk production

• Signalment: calves• Dx: skin scrapings Psoroptes ovis, female.

Courtesy of Dr. Dietrich Barth, Merial

Mange Mites• Leg mange: Chorioptes spp.• most common type of

mange in cattle in the USA• L.C: 3 weeks• C.S: papules, crusts, and

ulcerations on the legs and can spread to the udder, scrotum, tail, and perineal area

• Reportable in some statesChorioptes bovis, female. Courtesy of Dr. Dietrich Barth, Merial

Mange Mites

• Demodex bovis• C.S: damages hide,

follicular papules and nodules: withers, neck, back, and flanks

• Dx: deep skin scrapings

• Usually resolves with time

Mange lesions

Mosquitoes

• Mosquitoes are small insects: piercing-sucking mouthparts

• Female mosquitoes suck blood

• C.S: painful bites, unthriftiness, and occasionally death by suffocation or heavy blood loss

TICKS

TICKS• Body is a fusion of the thorax and abdomen produces a sac-

like, leathery appearance. • Class Arachnida • Bears recurved teeth • 4 developmental stages: egg, 6-legged seed or larval stage, 8-

legged nymphal stage and 8-legged adult.

Babesiosis• Babesiosis: Red water fever

– Boophilus annulatus• Vector for Babesia bigemina:

PROTOZOA– L.C: May/June, moving cattle to new

pasture– Signalment: Cattle, small ruminants,

water buffalo, reindeer, American bison – C.S: inflammation, itching and swelling

at the bite site, regenerative anemia: red urine, abortion, unthrifty, neurological signs (seizures, blindness)

– Dx: blood smear– Tx: tetracycline

Babesia/ Piroplasmosis in blood smear: Wright or giemsa stain

Anaplasmosis

• Transmission– Vector borne

• Ticks: Dermacentor andersoni, Boophilus, Rhipicephalus , Ixodes , Hyalomma , and Ornithodoros

– blood sucking flies and mosquitoes.

– mechanical vector: scalpels, needles, and tatoo

– Organism: Anaplasma marginale, rickettsial

• Signalment: cattle, sheep, goats, wild ruminants; > 3 yrs; carriers for life, bos taurus RMSF

Anaplasmosis• C.S: progressive anemia

• peracute• Acute: febrile, lose

condition rapidly, anorexia, dec. milk production, GI: constipation, depressed rumination, brown urine (hemoglobinuria does not occur), abortions, cerebral anoxia > aggressive

• Tx: tetracycline

Anaplasma marginale infection in bovine blood, Wright-Giemsa, 100X oil immersion. Intracellular organisms appear as basophilic, spherical inclusions that are generally located near the margin of erythrocytes. Frequent echinocytes are present. The hemat Courtesy of Dr. John W. Harvey

References• Holtgrew-Bohling, Kristin, Large animal clinical procedures for veterinary t

echnicians, 2nd edition, Elsevier, 2012

• http://edis.ifas.ufl.edu/ig130• http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-1932/VT

MD-7000web.pdf• http://www.cfsph.iastate.edu/Factsheets/pdfs/bovine_babesiosis.pdf• http://

vetmed.iastate.edu/vdpam/extension/beef/current-events/anaplasmosis-iowa

• 5 minute veterinary consult: Ruminant• http://www.vet.k-state.edu/depts/vmth/agpract/articles/

Common_Flies.pdf• http://www.uwyo.edu/vetsci/courses/patb_4110/2-7/

class_notes.htm#Ectoparasites_of_cattle• www.vetmed.isu.edu

References

• http://www.vetmed.ucdavis.edu/vetext/INF-DA/INF-DA_HEARTWATER.HTML

• http://www.animalhealth.bayer.com/3380.0.html

• http://parasitology.cvm.ncsu.edu/quiz/ruminant/exam3/ruminantquizFQ.php

• http://vetpda.ucdavis.edu/parasitolog/Parasite.cfm?ID=40