Parasitology Exam-arachnida

Question 1

General characteristics

Answer 1

• if eyes simple
• no wings
• patella between femur and tibia
• suckers, claws, setae
• adults and nymphs with 4 pair of legs
• larva with 3 pair of legs
• capituli/gnathosoma with palps, hypostome, chelicerae
• idiosoma= podosoma with legs, opistosoma w.o legså

Question 2

Pathological significance

Answer 2

• allergenic
• traumatic injury
• depleting action
• transmission of disease

Question 3

Order Astigmata

Answer 3

Mange mites:

• sacoptes
• psoroptes
• otodectes
• notoedres
• knemidocoptes
• chorioptes

Question 4

Genus Sarcoptes

Sarcoptes scabiei

Answer 4

-host adapted strains
-small size mites
-rounded body, spines and setae
-round capituli w chelicerae, maxipalps
-short limbs with suckers and Pericles
-males= 1,2,4th limb with suckers
-females=1,2nd limb with suckers
Biological cycle:
-egg>larva>3nymph stages>adult
-in epidermis
-females burrow deep to lay eggs
-nymphs and fertilized females are infective

Question 5

Genus psoroptes

Answer 5

• non burrowing mites
• wool/fur, ears
• longer legs
• pointed capituli
• suckers with pretarsi
• feeds on lymph

Question 6

Genus otodectes

Answer 6

• ear mites
• in ears
• similar to psoroptes but no pretarsi

Question 7

Genus knemidocoptes

Answer 7

• in birds, mainly psittaceans
• beak, feathers, legs
• similar to sarcoptes

Question 8

Genus Demodex

Answer 8

• host specific
• in hair follicles, sebaceous glands
• elongated body w two well differentiated regions: podosoma, striated opisthosoma
• common in human, increase with age
• May cause folliculitis, transmission of streptococcus pyogenes
• May cause granulomatous reactions in internal organs

Question 9

Genus Cheyleitella

Answer 9

-“walking dandruff” mites

Question 10

Genus Neotrombicula

Answer 10

• only larval stages parasitic
• frequent in end of summer-autumn
• cause circular patches btw eyes in dogs

Question 11

Genus Dermanyssus

Answer 11

• gnathosoma w chelicerae and elongated maxipalps
• well developed legs
• idiosoma w shields
• hematophagus
• birds and domestic rodents, zoonotic
• nocturnal
• allergic reactions

Question 12

Genus Varroa

Answer 12

• in honey bees

- vectors of DWV in honey bees

Question 13

Order prostigmata

Answer 13

• demodex
• cheyletiella
• neotrombicula

Question 14

Order mesostigmata

Answer 14

• dermanyssus

- varroa

Question 15

Order metastigmata

Answer 15

Ticks
Ixodiadae:
-ixodes
-rhipicephalus
-dermacentor
Agrasidae:
-argas 
-ornithodoros

Question 16

Family ixodidae

Answer 16

Hard ticks

• respiratory spiracle after last coxa
• dorsally visible gnathosoma/capituli w maxilar palps, chelicerae, hypostome w retrograde teeth
• idiosoma
• scutum/dorsal shield different btw species
• adults have genital+anal opening, larvae and nymphs only anal
• permanent parasites
• egg>larva>nymph>adult
• life cycle with 1-3 hosts

Question 17

Genus Ixodes

Answer 17

Transmission of:
-tularemia
-Lyme disease
-erlichia
3 hosts life cycle

Question 18

Genus Dermacentor

Answer 18

Ornamented
Transmission of:
-babesia canis
-q fever
-Rocky Mountain spotted fever
-tularemia
Generally 3 hosts life cycle

Question 19

Genus Rhipicephalus

Answer 19

Transmission of:
-babesia canis
-hepatozoon canis
-erlichia canis
-filaria in dogs
-Mediterranean spotted fever
-tularemia
3 hosts cycle

Question 20

Family argasidae

Answer 20

Soft ticks
-ventrally located capituli
-camerostome hiding capituli
-no sclerotized scutum 
-hypostome with less teeth
-several egg laying=more feedings
-egg>larva>2-6 nymph stages>adults
-nocturnal
-survive long time w.o feeding
-coral gland secretion when feeding
Differentiation:
-dorsal discs
-pointed capituli (ornithodoros)
-hypostome morphology

Question 21

Genus argas

Answer 21

• mainly birds and bats

- inoculation of toxins

Question 22

Genus ornithodoros

Answer 22

• mammals and bats

- vector of African swine fever