Parasitic Mites

Question 1

how mites cause disease to host

Answer 1

some suck blood and cause anemia
dermatosis, irritation & inflammation @ bite, oozing lymph
–itchy, self mutilation
facilitate secondary bacterial infections

Question 2

Mesostigmatid mites

Answer 2

stigmata between 3rd and 4th pair of legs
legs evenly spaces in anterior 1/2
claws on end of tarsi
most free-living, some parasitic

Question 3

dermanyssus gallinane

Answer 3

red roost mite in poultry
found in nests and bedding
-vampire model, OFF HOST unless feeding
anemia results from blood sucking habits
zoonotic
DX: needle-like cheleceria

Question 4

ornithonyssus sp.

Answer 4

poultry and rodents
found ON HOST
annoyance, irritations, discomfort
DX: scissor-like cheleceria

Question 5

astigmatid mites

Answer 5

no stigmata bc respiration cutaneous
2n and 3rd pair of legs widely separated
suckers on end of tarsi
most are parasitic (surface dwelling or skin burrowing)

Question 6

psoroptes ovis

Answer 6

surface dwelling mite
ON HOST
pierce skin w needle-like chellicerae, feed on oozing serum
psoroptic scab formed from coagulated serum
hair loss from rubbing and inflammation of dermis
DX: mites @ edge of scab
suckers on long pedicles at end of tarsi
REPORTABLE

Question 7

chorioptes bovis

Answer 7

surface dwelling mite
ON HOST
does not pierce skin
feeds on sloughed epidermal/ epidermal debris
superficially mildly pruritic, flaky dermatitis
self-limiting
DX: mites on host in areas of dermatitis
short suckers at end of tarsi
NOT REPORTABLE

Question 8

otodectes cynotis

Answer 8

surface dwelling mite
life cycle in outer ear canal on host
does not pierce skin
feeds on sloughed epidermal/ epidermal debris
superficially mildly pruritic
DX: ear swab of outer ear canal and observation of mites
suckers at end of leg
black, waxy cerumen (droppings)

Question 9

sarcoptes spp

Answer 9

skin burrowing mites
cubby body w short legs
ON HOST
burrow into and tunnel under the skin
**on hair less portions of body
Feed on serum, fluids, host proteins
sarcoptic scab formed oozing serum resulting from self mutilation
-hair loss from rubbing and inflammation of dermis extends suitable habitat for more mites
DX: deep skin scape @ edge of scab
REPORTABLE

Question 10

sarcoptes spp pruitic, papular, erythema related to

Answer 10

defecation and eggs laid in tunnels

Question 11

sarcoptes scabiei var canis

Answer 11

canine mange mite
burrowing
-hard to demonstrate so deep scrape crusty lesion
alopecia inguinal areas
pineal/pedal reflex
–scratch underside of ear flap
anus on ventral side

Question 12

notoedres

Answer 12

feline mange mite
often on surface fur
-easier to demonstrate on skin scrape
anus on terminal margin of ventral surface

Question 13

ear mite treatment

Answer 13

clean ears 1st
Milbemite

Question 14

scabies treatment

Answer 14

revolution @ monthly labeled dose

Question 15

demodectic mange

Answer 15

localized
erythema around muzzle
alopecia around eyes and pinnae
immune naaive animals can obtain from nursing on mother
self limiting

Question 16

Demodectic mange from secondary

Answer 16

generalized
red mange w/ dry flaky skin
erythema around elbows and boney projections
alopecia around eyes and pinnae
immuno-compromised animals
**must identify underlying condition
**difficult to control, impossible to cure

Question 17

cheyletiella

Answer 17

walking dandruff mite
massive palpal claws
DX: brushing fur
-KOH digestion w/ sugar floatation
in dogs, cats rabbits
zoonotic potential

Question 18

chigger mites

Answer 18

small, nearly microscopic
intense inflammatory response
salivary component used to dissolve/ liquefy host tissue for food
-necrotizes skin forms stylostome feeding tube
-head attached to host for duration of feeding
only larvae parasitic

Question 19

chigger mites larvae

Answer 19

6 legs
bright orange
ears of cats and dogs

Question 20

treatment/ control of mites

Answer 20

macrocyclic lactones
(IVM, moxidectin)