Parasite Exam 2 TA

Myiasis

• parasitic infection feeding on dead or living tissues

• predilection site

  • obligate parasite: stomach, nasal sinuses

  • accidental parasite: GIT by accidental ingestion

  • facultative parasite: soiled wounds or bedding, necrotic areas, broad host range, important for forensic entomology

• significant animal welfare issue

Calliphordae blowflies

• Lucilia

• Phormia

• Calliphora

• Cochliomyia (new world screwworm requires living tissue)

Oestridae bot/warble flies

• nostril flies (Oestrus nasal bots in sheep, Gedoelstia),

• bot flies (Gasterophilus stomach bots in horses)

• Warble flies (Hypoderma cattle grubs and warbles)

Sarcophagidae Flesh flies

• Sarcophaga

• Wohlfahrtia

Blow flies

• host: sheep, pet rabbits

• geography: North America, summer season

• Morphology: Green, blue, black, metallic, medium-sized

• overwinter: pupal form

• predisposing factors: ammonia, sulfur compounds, volatile organic acids produced by bacteria in skin wounds, high temp and humidity leading to wool rot, soiled fleece, wounds.

Greenbottles blowflies

• LUcilia

Blackbottles blowflies

• Phormia

Bluebottles blowflies

• Calliphora

Secondary Screwwrom blowflies

• Cochliomyia macellaria

Hairy maggot blow fly

• Chrysomy rufifacies

Primary flies

• initiate a strike on living animal

• larvae can penetrate intact skin

• Lucillia

• fly strike

Secondary flies

• feed on decaying and dead flesh

• attack areas already affected during primary fly strike

• Phormia and Calliphora

Tertiary flies

• found when host is near death

• Sarcophaga and Wohlfahrtia (ie flesh flies)

blow fly pathology

• severe skin damage and traumatic myiasis can cause secondary infections

• proteolytic enzymes digest and liquefy tissues

• production losses due to death, septicemia, anorexia, distress, poor condition

• mortality rate is 10%

• fly strike leaves a distinctive grey stain on wool

• some maggots feed on fat

• obligatory myiasis requires living hosts to complete their life cycle

Calliphoridae New world screwworm

• obligate

• geography: tropical and subtropical areas of the Americas

• feeding: larvae on living tissue eat the host alive

• hosts; warm-blooded animals, cattle and sheep most common

• Eradication: sterile male technique

Cochliomyia hominivorax

• New world screwworm

Calliphoridae blow fly morphology

• metallic green to blueish green with 3 distinct horizontal stripes on their thorax (stripes distinguish from blue bottle flies)

Oestridae bot flies

• morphology: large, hairy, adults have vestigial mouthparts

• feeding: larvae are obligatory parasites of large mammals, adults do not feed

• species:

  • Hypoderma

  • Oestrus

  • Gasterophilus

Oestridae Oestrus bot flies

• nasal bot of sheep (Oestrus Ovis)

• morphology grey fly, black spotted abdomen, short brown hair

• repro: VIVIPAROUS

• predilection site: nostrils, masture nasal sinuses

• migration: frontal sinus as L3

• feeding: larvae attach to mucosa

• CS: nasal discharge, sneezing, rubbing nose, neuro signs “false gid”

• pathology: Pasterurella, immunosuppression, pneumonia, fly worry, panic, lowered feed conversion.

• zoonotic

Oestrus ovis

• nasal bot of sheep

Oestridae Gasterophilidae botfly

• morphology: large dark fly, yellow hair, red eggs around cardia (G. intestinalis), yellow in pylorus and duodenum (G. nasalis)

• feeding: adults do not feed

• overwinter: inside host

• hatching: stimulated by licking

• predilection site: stomach of equines, eggs in hair

• pathology: none, rarely stomatitis, local inflammation of the stomach

• treatment: at owner request

Gasterophilidae intestinalis

• red eggs around cardia

Gasterophilidae nasalis

• yellow in pylorus and duodenum

Hypoderma

• warble flies cattle grubs (heel flies and gadflies)

• geography: Northern hemisphere, North America, Mexico, Canada

• development: subcutaneously in cattle

• morphology: resemble bees, orange-yellow hair with broad band of black hair in the middle

• predilection site: hair, lower parts of the body (H. bovis), eggs in row below hocks (H. lineatum)

• migration: larvae subcutaneous, CT of esophagus, spinal column

• CS: gadding, injury, local inflammation, secondary bacterial infection, bloat, spinal canal paraplegia, hypersensitivity (larvae rupture)

• pathology: hole punch effect

Hypoderma pathology

• Hole punch effect

Hypoderma predilection site

• hair

• lower parts of the body (H. bovis)

• eggs in rows below hocks (H. lineatum)

Oestridae Cuterebrinae

• morphology: large, hairy, blue to black abdomen, adults have vestigial mouthparts

• feeding: adults do not feed, larvae in boils of skin

• hosts: rodents, rabbits, dogs, cats, warm-blooded animals

• geography: western hemisphere, Americas

• predilection site: eggs in burrows in bushes, attach to host body and enter the skin through boils, eggs attached to mosquitoes and transmitted through feeding of mosquitoes.

• Cuterebra and Dermatobia hominis

Dermatobia hominis

• humans and larger mammals and birds

• attach eggs to blood-sucking flies (mosquitoes).

• when mosquitoes feed, egg hatch and penetrate skin of host.

Cuterebra spp

• parasites of rodents and rabbits (dogs and cats)

• western hemisphere, throughout the Americas

• eggs laid around burrows as host brushes past eggs hatch and larvae attach to host and enter body and migrate to specific sites.

Sarcophagidae

• flesh flies

• cutaneous myiasis

• hosts: rabbits, dogs, cats, mink, fox, humans.

• repro: VIVIPARIOUS

• predilection site: larvae on wounds and genitals, pupate in soil

Sarcophagidae flesh flies

• Wohlfahriis vigil

• Sarcophaga haemorrhoidalis

Wohlfahrtia vigil flesh fly

• dorsal surface of the thorax is marked with three longitudinal bands, while the dorsal surface of the abdomen exhibits three, well-defined rows of oval black spots which are confluent with one another.

Siphonaptera fleas

• morphology: wingless, laterally compressed, 3rd pair of legs enlarged for leaping.

• hosts: mammals and few birds, nest animals (nidicolous)

• feeding: both sexes take blood meal, larvae feed on organic debris and fecal blood.

• adult emergence triggered by vibration, temperature and light intensity.

• 95% of population in environment

• metamorphosis: complete

• treat environment for fleas

Ctenocephalides fleas

• ubquitous

• wide host range including humans

Ctenocephalides felis

• cat flea

• very common

Ctenocephalides canis

• dog flea

Ceratophylus gallinae

• bird flea

• wild birds, mammals

Xenopsylia cheopis

• oriental rat flea

• transmits Yersinia pestis (bubonic plague)

Purex irritans

• human flea

Echidnophaga gallinacean

• stick tight flea

• serious chicken flea

• affects egg production and feed efficiency

Tunga penetrans

• jigger

• chique

• sand flea

• burrows into skin

• affects humans and pigs

Spilopsyllus caniculi

• rabbit flea sometimes on cats

• adapted life cycle

Flea importance intermediate hosts

• Dipylidium caninum

• Hymenolepis tapeworms

Flea importance pathology

• irritation

• hypersensitivity

• flea allergy dermatitis (hypersesntivity Type 4, Th1 response) within the flea triangle

• anemia

• elephant skin

• thickening

  • FAD is the most common dermatologic disease of domestic dogs

Flea importance diagnosis

• history

• chronic lesions

• wet white paper test

• intradermal allergy tests

• vigorous combing

Controlling fleas

• target adults on hosts and immature stages in environment

• FAD - immedizte intervention to prevent continued reaction

  • adulticide first

  • corticosteroids and antibiotics

  • larvalcide second

• rid animal of current infection and prevent re-infection

• eliminate the environmental reservoir

• 1 flea can cause hypersensitivity

• drugs: frontline, stronghold, advantage, prac-tic, nexgard

Phthiraptera lice

• obligate parasite

• morphology: wingless insects, dorso-ventrally flattened 3 pairs of legs with single claws

• hosts: host specific, operculate eggs cement to hair shafts

• transmission: direct contact, fomites, limited survival off host

• seasonality: late winter, early spring

• metamorphosis: incomplete

• 2 groups: sucking and chewing

Sucking lice : Anoplura

• host: mammals

• morphology: piercing mouthparts, pointed head, narrow head

• feeding: blood and tissue fluids

• Haematopinus (cattle, pigs, equid), Linognathus (dog, sheep, goat, cattle), Solenopotes (cattle)

chewing lice: Mallophage

• host: birds and mammals

• morphology: cutting and grinding, broad head

• feeding: skin scales, hair, feathers (superficial)

• Damalinia bovicola (sheep, goat, cattle, equid), Trichodectes (dogs), Felicola (cats)

Bird lice

• Chewing lice only

• commonly found: poultry houses

• pathology: anemia, fatal in chicks, damage to feathers

• feeding: superficial causing irritation

• predisposition: overcrowding, unhygienic situation, debeaking, improper grooming

Goniocotes gallinae

• fluff louse

Menacanthus stramineus

• chicken body louse

Cuclotogaster heterographus

• chicken head louse

Lipeurus caponis

• chicken wing louse

Menopon gallinae

• shaft louse

Lice pathology

• light infestation is considered normal

• heavy infestation: pediculosis, pruritis, alopecia, hide damage, weight loss, anemia, myiasis, secondary bacterial infection.

• vectors for: swinepox, Mycoplasma, anaplasma, dermatomycosis

• intermediate host: trichodectes canis for dog tapeworm

• diagnosis: CS, egg detection, adult detection, ID based on host species, site of infection, and morphology

• predilection site: head, neck, back, tail

controlling lice

• several flea products effective against lice

• second treatment required 2 weeks later to kill emerging lice

• sucking lice: injectable avermectins

• biting lice: ivermectin pour on

• prevent reinfection: clean grooming equipment

• seasonal: just before housing for winter

Acricide

• any drug or formulation for killing acarids (mites or ticks)

Insecticide

• any drug or chemical used for killing insects

pesticides

• substances/mixture of substances for preventing, destroying, repelling or mitigating any pest - used in crop protection

Endectocide

• parasiticides (macrocyclic lactones) that affect both nematodes and arthropods

Curative

• cure/heal sick animals following the diagnosis of infection

Metaphylaxis

• treatment of whole group of animals after diagnosis of infection in part of the group to prevent the spread of infectious disease

Preventative

• treatment of a group of animals before clinical signs to prevent the occurrence of disease or infection (can cause resistance)

Strategic

• treatment at certain time points according to parasite biology

MItes

• Morphology: 2 body parts, 4 pairs of legs, pedipalps (sensory organ), larvae only have 3 pairs of legs, pedicles can end in claws or suckers

• metamorphosis: incomplete

• host: majority are free living, some plant predators, some obligate parasites

• pathology: 85% of asthma sufferers are allergic to free living dust mites, mange, cutaneous hypersensitivity, anemia

• intermediate host: tapeworms of cattle, sheep, horses

• feeding: blood, lymph, skin debris, sebaceous secretions

• life cycle: parasitic mites spend their entire lives on the host

• transmission: direct contact between hosts

• seasonal: winter is a problem

• classification: burrowing or non-burrowing

• demodex folliculorum - mange, cigar shaped

Orbatida free living mites

• beetle like

• habitat: soil and vegetation on pastures

• transmission: ingested

• hosts: sheep and other grazing animals

• intermediate hosts: cestodes, moniezia and anoplocephala

Non-Burrowing MItes

• morphology: oval body, long legs

• predilection site: surface of skin

• transmission: direct contact, indirect via scratching

• feeding: skin scales and tissue, superficial blood sucking

• diagnosis: skin scrape at edge of lesion, serum ELISA

• pathology: dermatitis

Non-burrowing mites

• Psoroptidae

  • Psoroptes

  • Chorioptes

  • Otodectes

• Cheyletidae

• Dermanyssidae

Psoroptidae Psoroptes

• sheep, cattle, horses, rabbits, highly contagious mange

• sheep scab, cattle scab, elk scab, Psoroptes cuniculi in ear of rabbit it dormant

Psoroptidae Chorioptes

• sheep, cattle, goats, horses, rabbits

• notifiable

• differentiate from Psoroptes by short non-segmented pedicel and rounded mouthparts instead of pointed

• most common mange in cattle, can survive off hosts

Psoroptidae Otodectes

• ear mites of cats and dogs with unsegmented pedicel

Psoroptidae Cheyletidae

• Psorergates

• Cheyletiella

• walking dandruff in dogs primarily (surface mite)

• zoonotic

• claws on palps

Psoroptidae Dermanyssidae

• Dermanyssus

• Ornithonyssus

• pneumonyssoides

Otodectes Cynotis

• common ear mite

• host: dogs, cats, foxes

• morphology: unsegmented pedicle

• predilection site: deep ear canal

• CS: grey to black exudate with crusts

• pathology: hematoma, head shaking, pruritis, secondary bacterial infection

• Diagnosis: dark debris, moving white specks on otoscope

Raillietia

• ear mites

• hosts: cattle and goats

• pathology: blockage of auditory canal, inflammation, hearing loss

• Diagnosis: dark debris, moving white specks on otoscope

Dermanyssidae Pneumonyssoides caninum

• canine nasal mite

• morphology: oval, pale yellow

• CS: head shaking, inverted sneezing, nasal secretions

Dermanyssus gallinae

• red mite of poultry or pigeon mite

• morphology: large, elnogated chelicerae and stylet like piercing mouthparts, greyish white, but red when engorged

• predilection site: cracks and crevices

• not a permenanet ectoparasite

• only one which punctures skin

• feeding: larvae don’t feed, nymphs feed and fall off, can live for 8 months without feeding

• zoonotic

Dermanyssidae Ornithonyssus sylviarum

• northern fowl mite

• abundant in US

• main ectoparasite of laying birds

Trombiculidae

• mostly free living with some parasitic adaptations

• morphology: orange - red

• seasonal: late summer, early autumn

• habitat: grain storage areas

• predilection site: ears, eyes, toes (in humans = feet)

• parasitic: only larval stages

• hosts: not host specific, dogs, cats, birds, rabbits zoonotic

• Neotrombicula, Trombicula, Neoschoengastia americana (chigger mites, scrub itch mites, harvest mites)

Burrowing mites

• morphology: small, round, short legs

• Sarcoptidae (Sarcoptes, Notoedres, Trixacarus, Knemidocoptes)

• Demodicidae (Demodex)

Sarcoptes

• scab mite, scabies

• morphology: numerous transverse ridges and triangular scales on dorsum

• hosts: all domestic animals except cats and guinea pigs, zoonotic

• predilection site: stratum coleum of skin, all development within burrows in skin, dogs= ears, muzzle, face, elbows, pigs=ear

• feeding: pierce skin to suck lymph, epidermal cells

• pathology: inflammation, exudate, crusts, alopecia, allergic reaction to feces, molts, saliva, death in wildlife, papular eruptions in humans, strong sour odors

• diagnosis: skin scrape with some bleeding in paraffin oil

Notroedes cati

• cat scabies

• morphology: thumb print like striations on dorsum

• predilection site: skin of face, neck and ears

Knemidocoptes

• poultry scabies, only burrowing mite of birds

• morphology: stalked pulvilli in males, no spines or scales, legs do not go past body

• pathology: scaly leg (mutans), deplumbing itch (gallinae, burrow in hair shaft), tassel foot and scaly face/beak (pilae, non feathered parts)

Demodex

• burrowing mite

• common comensal of all animals

• hosts: mammals have their own host adapted species, most commonly the dog

• predilection site: hair follicles, sebaceous glands

• demodectic or follicular mange

• morphology: small, elongated cigar shaped

• not contagious

• transmission: mom to baby during suckling

• diagnosis: deep skin scrapings

• treatment: rare, if needed antibiotics for secondary bacterial infection or steroids for inflammation

Demodex localized form

• good prognosis, few lesions of small diameter

Generalized form demodex

• prognosis good, several lesions of large diameter

demodex squamous demodicosis

• good prognosis, similar to dandruff

pustular demodicosis demodex

• poor prognosis, pruritic due to secondary baccterial infection

demodex gatoi

• in cats is very itchy without secondary infection and is contagious

Varroa destructor

• bee mite

• predilection site: under wings

• host: honeybees

• feeding: body fat of adult bees and bee larvae

• vector: viral diseases in bees

• geopgraphy: originally from asia, now worldwide

• pathology: death

Ticks

• geography: worldwide

• arthropods

• morphology: 1mm to 3cm

• survive off host for long periods of time, but usually host seeking

• second to mosquitoes in public health crisis

• pathology: skin lesions, secondary bacterial infections, economic losses

Ixodidae

• hard ticks

• morphology: scutum, prominent mouthparts, festoons, ornate, stigmata, eyes (depending on species)

• acarina: has a Haller’s organ to detect scent, CO2, humidity.

• feeding: blood

• chelicerae are used to pierce the skin and begin securing the tick to the host

• hypostome anchors the tick and is responsible for saliva flowing out of the tick and blood flowing in

• species: Ixodes, Dermacentor, Rhipicephalus, Haemaphysalis, Hyalomma, Amblyomma

One host tick life cycle

• remain on the host for the whole life cycle until drop off to lay eggs

• Dermacenor nitens

• Rhipicephalus

two host tick life cycle

• 1st host is usually small mammals or birds

• 2nd host is large animals, small animals, not host specific

• usually takes about 2 years

• Rhipicephalus

• Hyalomma

Three host tick life cycle

• 1st host is usually small mammals

• 2nd host is small mammals

• third host is non-specific

• usually takes about 3 years

• Ixodes

• Dermacentor andersoni and variabiles

• Rhipicephalus sanguineus

• Haemaphysalis

• Amblyomma

Ixodes

• hard tick

• morphology: small, lack of eyes, distinct anal groove, inornate, 3 host ticks

• worldwide

Ixodes ricinus

• sheep and caster bean tick

• host: mammals, birds, reptiles

• seasonality: varies

• Europe

• Anoplasma, Babesia, Borrelia

Ixodes scapularis

• blacklegged deer tick

• host: small mammals, lizards, birds, cattle

• seasonality: early spring, fall

• US and mexico

• Borrelia, Anaplasma, Babesia

Ixodes pacificus

• western blacklegged tick

• host: mammals

• seasonality: fall and winter

• western US

• Borrelia, Anaplasma