Ectoparasites of small animals

Question 1

What part of a tick aids in attaching & staying on host?

Answer 1

teeth on the hypostome & palps

Question 2

Ticks feed via…?

Answer 2

hypostome containing teeth

Question 3

Structural difference between hard & soft ticks?

Answer 3

hard ticks have scutum, soft ticks do not

Question 4

Argasidae - soft tick (Ornithodoros)…distribution…habitat… diseases…?

Answer 4

Africa , India, Sri Lanka
Sandy soils, and places where animals/birds gather
transmits viruses causing diseases like Q-fever, African swine fever, African relapsing fever

Question 5

Name a tick found in birds & describe the effects they may have…

Answer 5

Argus spp. (fowl tick)
Hosts: chickens, turkeys, ducks…
retard bird growth
transmit fowl cholera

Question 6

Argasidae - soft tick (Argus) major effects on poultry…

Answer 6

blood loss -> anaemia -> fatal
bird emaciation, weakness, retarded growth
uneasiness during roosting (as ticks feed at night)

Question 7

Argasidae - soft tick (Argus) diagnosis…

Answer 7

Red spots on skin

Check feathers for larvae & cracks in fowl house for adults

Question 8

What are the 3 types of ticks?

Answer 8

one-host tick
two-host tick
three-host tick

Question 9

Define one-host tick

Answer 9

all 3 stages (instars) engorge on same animal

Question 10

Define two-host tick

Answer 10

larvae engorge & moult -> nymph on one host -> engorges -> drops off -> moults & young adult seeks out a new host

Question 11

Define three-host tick

Answer 11

require a different host for each instar (stage), drop off after engorgement and moult on the ground

Question 12

Paralysis tick…scientific name?

Answer 12

Ixodes holocyclus - three-host tick

Question 13

Ixodes holocyclus (paralysis tick) lifecycle…

Answer 13

slide 22…

Summer (eggs) -> Autumn (larvae) -> blood meal -> winter (nymphs) -> blood meal -> Spring (adults)

Question 14

Where are paralysis ticks found in Aus?

Answer 14

moist coastal areas of East Aus

Question 15

Indications that dog has been bitten by paralysis tick…? Treatment?

Answer 15

change in bark -> ‘wobbliness’ in back legs -> complete paralysis -> death
Treat with anti-tick serum (IV) keep dog in quiet & darkened environment

Question 16

Brown dog tick…scientific name?

Answer 16

Riphicephalus sanguineus - three-host tick

Question 17

Difference between mites & ticks?

Answer 17

hypostome never armed with teeth

Question 18

General characteristics of demodex (mite)…

Answer 18

elongated body
short legs
parasitic in hair follicles

Question 19

Hosts of of demodex (mite)…

Answer 19

dogs, cats, sheep, goats, pigs, horses

Question 20

Voracious ectoparasites of poultry…?

Answer 20

poultry red mite (Dermanyssus gallinae)
tropical fowl mite (Ornithonyssus bursa)
northern fowl mite (O. sylvarium)

Question 21

Demodex biology…?

Answer 21

Entire life is spent on the host
Life cycle completed in 18-24 days in hair follicles
Female lays 20-24 eggs in the hair follicle
DIRECT contact

Question 22

Demodex predisposing factors…?

Answer 22

age, nutritional status, stress, genetics

Question 23

Demodex pathology…

Answer 23

Canine demodectic mange at 3-9 months old
no. of mites proportional to disease severity
increased disease associated with immuno defects
thick, wrinkly skin

Question 24

Sarcoptes (important little mother fucker) hosts, infective stage, route of infection, typical symptoms (list 3)… (remember foxes in post-mortem prac)

Answer 24

IH & DH: most animals (dogs & cats)
infective stage: wandering larvae, nymphs & fertilised young females
route: transdermal to suck lymph
symptoms: skin irritation; inflammation & exudate & crusts form; hair loss

Question 25

Developmental conditions for fleas…?

Answer 25

13-32°C
50-90% humidity
Optimal conditions 23-26°C with 75-80% humidity
Light sandy soils (eg under houses)

Question 26

How can fleas jump so high?

Answer 26

protein resilin in their leg hinge - 97% elasticity

Question 27

Extent of flea problem…

Answer 27

more $ spent on flea control than any other product!
25% of $ small animal practice
heaviest in spring/summer
jump from host to host
zoonotic
most infections in cat
suck blood

Question 28

Most serious flea disease? Describe…

Answer 28

Flea Allergy Dermatitis (FAD)
Worse in dogs
intense itching (hypersensitive to flea saliva) -> scratching -> skin trauma -> skin thickening

Question 29

Flea diagnosis…

Answer 29

Fleas often absent -> look for faeces
Put suspect faeces on filter paper dampened with soap or detergent solution, a red halo develops as haemoglobin migrates through the paper

Question 30

Outline control & treatment of fleas…

Answer 30

numbers ++ with warmth/humidity
eggs -> ground where pupae survive on carpet/soil until host near (vibration)
Prevention: vacuum from environment; wash blankets in hot (60°C water) -> kill eggs; remove all flea reservoirs
Treatment: All animals in house -> kill adults, prevent dev. off host, repel fleas. Allergy: cortisone

Question 31

Drug treatments of fleas…

Answer 31

Lufenuron - insect growth regulator (tabs, susp., inject)
Selamectin - insect growth regulator (topical) -> also fucks up ear mites & sarcoptic mange
Fiprinal - blocks chloride channels
Imidacloprid - block ACh receptors (spray)

Question 32

Fleas can be vectors for other hosts causing disease. List 3 host vectors & disease they may transmit…

Answer 32

Rats - bubonic plague
Rabbits - Myxomatosis
Dogs - Dipylidium caninum (tapeworm)