Parasit - Lab Quiz 10-4

drraythe's version from 2015-05-13 20:28




Question Answer
What are the 9 general characteristics that all mites share?(1) NO antennae, wings, or compound eyes!
(3) Have peritreme, stigma & spiracles – except for Astigmata
(4) 4 developmental stages: egg → larva → nymph → adult (except for pnumoyssoides = no nymph stage)
(5) Larvae have 3 pairs of legs, adults & nymphs have 4 pairs (arachnids!)
(5) May be free living or parasitic = facultative parasites
(6) Most adult mites live 3-5 weeks
(7) All mites are susceptible to ivermectin!
(8) Must Txall animals in contact for minimum of 2 life cycles
All Mesostigmata mites?Are all blood feeders; Live on birds & rodents (& other things), ZOONOTIC if DH is not around!! Legs are confined to anterior end (1/2) of body; the stigma is between the 3rd or 4th coxae; have peritreme & have ‘chelicerae’ (piercing mouthparts); & can be collected via ‘BERLESE Technique’
What is the ‘BERLESE Technique’?
Ophionyssus mite?Order Mesostomata. Blood sucking mites of reptiles; may cause difficulty in shedding skin, anemia, dehydration, dermatitis & can vector dz; possibly ZOONOTIC
Ophionyssus natricus(1) Blood sucking mite in reptiles
(2) CS: Difficulty shedding/crunchy looking/dehydrated
(3) Peritreme (& stigma) is between 3rd & 4th leg
(4) Berlese technique
(5) Ddx = Pentastomes
Pneumonyssoides mite?Order Mesostomata. Blood sucking nasal & paranasal respiratory mites of dogs (P. caninum); ovoviviparous (larvae in egg); NO nymphal stage;
Xmission: Direct transfer of 6-legged larvae from dog to dog
CS: can be subclinical, or coughing, reverse sneezing, rhinitis, head shaking, chronic sneezing, nasal discharge, impaired sense of smell, & epistaxis
Dx: Rhinoscopy, nasal swabbing, nasal flushing
Pneumonyssoides Quick recallNasal/paranasal mite in dogs
CS: Coughing, reverse sneezing, rubbing nostrils on floor, epistaxis
Dx: Rhinoscopy, nasal swabbing, nasal flushing
Sternostoma mite?Order Mesostomata
DH: Birds (canary, finch); Live in the respiratory tract, air sacs where they suck blood
CS: Asymptomatic or respiratory illness: Lose voice; Shake head; Sneeze
Dx: Moisten/part feathers in neck → trans-illuminate trachea (black spots); Necropsy - black spots in respiratory tract
A bird brought into your clinic is open mouth breathing, what might do you think they have?Sternostoma


Question Answer
All Astigmata mites?Lack stigmata, respire through their skin & have pedicles
Sarcoptes mite?
Order Astigmata. Respiration thru skin. Some host specificity; DH: Dog, ferret, swine, cattle, etc. (WIDE RANGE); ZOONOTIC; REPORTABLE IN ALL LG ANIMALS (EXCEPT SWINE), Long, unsegmented pedicels, Anus = posterior edge body. Burrows deep, need DEEP skin scrape to dx
CS in Cattle: EXTREME pruritus, Hyperkeratosis, Udder cleft dermatitis, Self-trauma, Highly contagious
CS in Pig: Eyes, nose, back, sides, inner thigh surface, Hyperkeratosis
CS in Dog: Lateral elbow, pinna of ear, Follicular papules, erythema, crusts of dried serum, pruritus, hair loss hyperkeratosis (Puritus not seen in Norwegian scabies)
4 facts about Sarcoptes?(1) Zoonotic
(2) Reportable in large animals except pigs
(3) Highly pruritic
(4) Dx by DEEP skin scrape
Trixacarus mite?
Order Astigmata
DH: Guinea pig. ½ size of Sarcoptes
CS: Epileptic-like-seizures from Intense pruritus, Self-trauma Erythema, Papules, Hyperkeratosis, Alopecia, Lichenification
Knemidokoptes mite?
Order Astigmata.
Causative agent of “scaly legs” in chickens, turkeys & pheasants.
Dx = Deep skin scrape. Mites burrow in the epidermis of the legs, beak, back & vent, causing a thickening & deformation, “lifting the scales” causing a 'Flying Saucer' effect
KnemidokoptesScaly legs in birds - The mite looks like a 'Flying saucer' & causes 'Flying saucer' effect on scales!
(remember this one cause it looks like an alien word, aliens drive flying saucers which had fold out LEGS for landing)
You are at a farm & notice several turkeys with thicken ceres, scales, missing feathers & thicking around the vent. You take a skin scrape. What do expect to see under the microscope?Knemidokoptes!
Psoroptes mites? (2)
Psoroptes is Reportable in? What is special about it?All large animals! but are more likely to be found in the ear canal of rabbits
CS = Head shaking & will have a thick crust in the ears
Psoroptes has long 3 segmented pedestals
Chorioptes mite?
You are at a small horse farm, owners also keep 2 cows. You see the depicted on the horses & notice some dermititis b/t the toes of the cow. How take skin scrapings from all the animals. What do you expect to find?
This naked hedgehog enters your clinic. What is your first thought?
Chorioptes (Hedgehogs w/ no quills or loose quills)
Otodectes mite?
Order Astigmata. Ear mites; Have short, unsegmented pedicles Infests the external ear canal & adjacent skin of dogs, cats, foxes & ferrets
CS: Pruritus of ears, Forms black debris in the ear canal, Animal may develop hematomas from violent shaking of the head
I say Otodectes you say? CS?Ear mites!
Animal may be shaking head/have black debris in the ear canal


Question Answer
Demodex mite?
Order Prostigmata. Host specific!!
Tx: Resolves spontaneously
Dogs – get from mom's skin while suckling
Cats – head & ear canals
Bovine – pinhead to egg sized nodules may appear
Sheep – necks, flanks & shoulders
Goats – nodular dermatitis in milk goats
Horses – Meibomian gland
DemodexCigar shaped mite w/ 8 legs
-Puppies present w/ hair loss & redness around the eyes (T-cell autosomal recessive gene)
-Cattle present w/ nodules. When you lance them you see these cigar/sausage shaped mites.
What is important to know regarding the Demodex genus?Causative agent of canine “red mange” = hair loss & scaling w/o pruritus (unless 2° infxn)
Inhabit hair, hair follicles & sebaceous glands; Host specific!!! Your client didn’t get it from their dog! Affected adults are normally immunocompromised (T-cell autosomal recessive gene)
Dx: DEEP SKIN SCRAPINGS or plucking of hairs at periphery of lesion, or (in LA) lancing a nodule & examining the debris
Common xmission from dam to pup during suckling (<7 mo) from the skin, NOT the milk!
Susceptible breeds: Shar-Pei, Great Dane, English Bulldog, Weimaraner, Alaskan Malamute, Rottweiler & many terrier breeds
Cheyletiella mite?
Order Prostigmata
Has characteristic 'Palpal Claws'
DH = Humans, dogs, cats & rabbits; Causative agent of “walking dandruff”= scaling & mild pruritus
ZOONOTIC & highly contagious
I say Cheyletiella you say?"Walking dandruff"