Parasitology 2 Flashcards
What makes a arachnida, the features and the two parts of the body
- 4 pairs of legs (3 pairs in larva)
- no antennae
- no wings
- body divided into 2 parts
1. gnathosoma (= capitulum)
[modified for specialised feeding]
2. idiosoma (= the rest)
Features of Ixodoidea
Ticks
- obligate parasites - neeed blood meal
- most of life cycle is spent off host (in most cases)
- variable host specificity (specialist (like a certain host - parasitise one host) / generalist)
What is the mouth piece of the tick and how does it work
- Flanked by palps - length and shape differentiate between species
- Tip of hypostome structures called chelicerae (cut into host)
○ Saliva is secreted which acts as a cement that lodges tick onto host via hypostome
What are the 3 distinct features you look for with ticks and the variations
1) anal groove
- present, posterior or anterior
2) Festoon - present ‘ornate’, doesn’t have then ‘inornate’
3) with or without eyes
- located near the edge of the scutum in females and near the second leg on the side in males
Tick life cycle at what stage how many legs
- larva (6 legs)
- nymph (8 legs) - looks like mini adult
- male and female (8 legs) - males tend to be more colourful, scutum is the whole back unlike females
○ When female drink blood they can expand rapidly - can drink lots of blood
What are the 3 types of tick lifecycles
1) 1 host tick, feed as larvae moults to nymph feeds then moult to adult
2) 2 host tick
1. first host
- Larvae feed become nymphs and then leave the host
- Lymph feeds and engorged nymphs will drop and find next host
2. second host)
- Become an adult and reproduce
- Females drop off and lay eggs
3) 3 host tick
2. Hatch into 6 leg larvae
3. 1st host, feed moult to lymph
4. 2nd host feed, moult to adult
5. 3rd host feed and reproduce
6. Female drop off and lay eggs - repeat
how do ticks get onto their host
Hunting
- Move up stick or blade of grass
- Tendrils on legs that allow you to grasp onto what walks by
- Questing - move around there legs
Are also about to see if have eyes, detect CO2 - very good hunters
What is the generalised soft tick lifecycle
Multiple hosts and lymph stages
- Need to have a blood meal between lymph stages moult
- Can be huge problem for poultry
1) 1st host Larvae moult into 1st lymph stage
- Between stages stay in environment - constantly leaving the hosts and infest the environment
○ Chicken coops are the perfect area
2) 2nd host (can be the same host), feed, moult to 2nd lymph stage
3) 3rd host, feed, moult
4) Can be repeated 7 times depending on the species
5) Finally adult and reproduce
List 6 effects ticks have on their host
- blood loss (tick can take 5ml of blood) - if have thousands on animals - losing litres of blood
- irritation, hypersensitivity
- damage hide - industry issue, production
- reduce growth rate of host
- produce toxins (can lead to paralysis)
- transmit protozoans*
List the 3 main differences between Ixodidae and Argasidae
Family Argasidae “soft ticks” - no scutum - mouthparts underneath - rapid feeders (hours) ○ Allows them to parasitise so many hosts Family Ixodidae “hard ticks” - scutum present - mouthparts anterior - slow feeders (days) ○ If producing a toxin the longer the feed the more concentrated the toxin
Argas persicus common name, type and distinctive features
the fowl tick
- soft tick
- reddish tick
- mouthparts concealed
- distinct patterned margin to body - IMPORTANT DISTINCTION
○ Colouring more concetrated at margin of anterior side
What is the lifecycle of argas persicus, how long can it survive
- eggs laid in cracks
- hatch in 3 weeks
- larvae feed for 5-10 days - unusual for soft ticks normally rapid
- moult in crevices
- nymphs feed in 2h
- nymph and adult nocturnal - if check chickens during the day won’t see, may see larval stages (due to long stage of feeding)
- larvae survive for 3 months without food
- adults survive for 3-5 years without food - just burn it down (chicken coop)
What is the pathogenesis, diagnosis and treatment for argas persicus
1) Death due to paralysis from larvae
2) anaemia
3) irritation
4) reduce egg production
5) transmit: ○ Borrelia anserina (tick fever) and
○ Aegyptianella pullorum
Diagnosis :
- find larvae on birds
- find adults in sheds
Treatment :
- organophosphate spray
- kerosene emulsion - burn the chicken coop as adults can last 3-5 years
Ornithodoros common names, where found, where live, host species, effect on host
“tampan ticks” - Or. moubata in Africa - Or. gurneyi in Australia ○ live in sand ○ feed on any host species ○ cause painful bites ○ transmit Q fever
Otobius megnini common name, where found, hosts, where found on host
spinose ear tick
- in North America, Africa
- adults free living
- larva & nymph live in ear - painful, balance is off
- horses, cattle, dogs
- found recently in WA
Ixodes what features are unique, are they native and list the 2 main examples and what they cause
- long palps
- anal groove in front of anus
- native ticks
I. holcyclus and I.cornuatus cause paralysis
Ixodes holocyclus lifecycle, host, seasons and what sex found on host
- 3 host tick
- on native mammals
○ Bandicoots are common host - life cycle takes 18 months
- larvae & adults in spring
- nymphs mainly in autumn
- males rarely found on host
Ixodes holocyclus effect on host, which hosts most susceptible, when do clinical signs develop
- all stages cause irritation & paralysis
- sheep, dogs & cats most susceptible: 1 female tick will kill a dog
- calves & foals also susceptible : 4 female ticks can kill a calf
- can affect humans (homophilic tick)
- females engorge for up to 21 days
- signs develop on days 5-6 - detect in domestic species at this time
○ ascending motor paralysis - die from paralysis of respiratory muscles - intense vasoconstriction
- native & domestic animals can develop immunity - if doing tick checks
Ixodes holocyclus treatment and distribution
- find & remove tick - very tiny, larval ticks look like a grain of sand (ears, underneath neck, under arm and legs)
- acaricidal wash
- hyperimmune serum
Other species - *Dermacentor variabilis and D. andersoni cause paralysis (North America)
Distribution - Unsure of exact distribution - more commonly around coast
- Can occur in Melbourne
Can be transported by human activity
Boophilus features list 4
- short palps with ridges
- pale legs - in comparison to the body
- anal groove behind anus, difficult to see
- engorged female has “waist” (sometimes)
○ Sometimes look like they have a belt
Boophilus microplus common name, where found, hostss
the cattle tick
- occurs in Central & South America, Southeast Asia
- introduced into northern Australia, goes into Queensland and down into northern NSW
- major cattle disease in northern Aust.
- host specific but occurs occasionally on horses, sheep, dogs & pigs
What is the lifecycle of Boophilus microplus
- 1 host tick
- life cycle takes 22 days
1) eggs hatch
2) “seed ticks” climb up grass
3) attach to passing cattle via questing
4) Moult to larvae & nymph remain on host
5) Moult to adult and reproduce
6) female ticks drop off after 18-37 days, most on day 22
○ drop off mainly in early morning
Boophilus microplus what are the 5 effects on the host
the cattle tick
1) irritation - ticks removed by grooming
2) damage to hides - loss of 25% of value
3) anaemia - each tick takes 1-5 ml blood
○ Resulting in anorexia (reduced appetite)
4) reduced growth rate and milk production
5) transmit protozoans**
○ Babesia
○ Anaplasma
○ Theileria
Boophilus microplus distribution in 1) southern limits 2) dry tropics and 3) wet tropics
○ Temperature humidity 1) at southern limits (SE Qld): ○ uniform rainfall and cool winters § winters suppress tick development ○ takes 3-4 generations in spring to build up again 2) dry tropics ○ temp. never limiting ○ dry winters § tick numbers increase in wet season 3) wet tropics ○ temp. never limiting ○ rain in all months ○ ticks all year round
Dispersal and survivial of Boophilus microplus on the soil
cattle tick
- larvae accumulate around site of egg mass
- can migrate short distances (<1m)
- can be blown up to 30m
- cattle avoid heavily infected areas
- can “spell” paddocks to control ticks
○ depending on climate, harder with warm weather and high humidity
- in summer 50% live 2 weeks, 10% live 4 weeks
- can be up to 11 weeks in cool weather
List 3 ways to control Boophilus microplus and which breed most resistant
the cattle tick
very good at developing resistance
1) chemicals
2) growth regulators - flurazuron
- zebu cattle naturally more resistant so require less
3) vaccine - ticks grow poorly and have low fecundity (not laying as many eggs)
- 70% effective, need 2 vaccinations
What are the features of the Haemaphysalis
- anal groove behind anus - others in front
- lateral projections on palps
H. longicornis common name, is it native, hosts, where occur and effects on host
- introduced into Australia
- common in SE Asia
- occurs on cattle & other hosts (eg., horses, dogs)
- 3 host tick
- occurs in eastern Australia
○ common in eastern Victoria - causes anaemia and hide damage
○ vector of Babesia gibsoni of dogs
List the 3 Features of Rhipicephalus
1) anal groove behind anus
2) basis capituli projects - projections (the neck where the mouth parts connect)
3) forked first coxa
R. sanguineus common name, is it native, where common, what are the 2 effects on host
brown dog tick” - common in tropical countries - introduced - common in northern Australia - uncommon but present in Melbourne - causes anaemia and irritation - vector of Babesia canis of dogs ○ Rocky mountain fever - kills children
Aponomma & Amblyomma features list 3 and list hosts
1) long mouthparts like excytoes
2) anal groove behind anus (unlike excytoes)
3) often brightly coloured
Hosts
- important on cattle in Africa and USA
- most Australian species occur on reptiles (one on wombat, one on echidna, one on kangaroos)
Features of arachnids and the two areas of the body
○ ticks and mites (parasitic) - 4 pairs of legs (3 pairs in larva) - no antennae - no wings - body divided into 2 parts 1. gnathosoma (= capitulum) [modified for specialised feeding] - chelicera - cutting 2. idiosoma (= the rest)
Features of mites, mouth parts, lifecycle. type of parasites, where found
- abundant, most free-living
- lack rows of teeth on hypostome
- have capitulum with palps and chelicerae
- life cycle : egg, larva (with 6 legs), can have several nymphs (proto-, deuto-, trito- depending on lifecycle), adults
○ Similar to ticks - can be : intermittent parasites in nests or burrows, or permanent parasites
- can be on: skin, in ears or respiratory system
List 4 generalised effects on hosts of mites
- blood loss
- Only in heavy infestation - Irritation
- Can lead to hypersensitivity - hair loss
- Mange mites - vectors of disease
In terms of spiracles where are they found on mesostigmata, trombidiformes and sarcoptiformes
Orders of the mites
Mesostigmata - Spiracles between coxae
Trombidiformes - Spiracles on capitulum (mouth parts)
Sarcoptiformes (no spiracles - respiration through body wall)
Ornithonyssus spp common name features, host, lifecycle and effect on host
- common on wild birds
- found in bird nests
- referred to as “starling lice” - not lice but can feed on bees
- feed on birds while in nest
- some remain on birds all the time
- blood feeders
- not host specific***
○ Not able to reproduce but can bite other hosts
Effect on host
1. cause severe anaemia
2. reduced egg production
Dermanyssus gallinae common name, general features, hosts, lifecycle and effects on host
- triangular anal plate* important
- parasite of birds & mammals
- life cycle : eggs, larva, 2 nymphs, adults
- eggs laid in crevices (like the chicken coop, hoping on and off the chickens, can use the same host but need to come off and go back on for a feed between life stages) - life cycle 7 days
- nocturnal
- blood feeders
Effect on host :
1. anaemia
2. irritation
3. transmit Borrelia anserina - (Spirochaetosis in birds)
Varroa destructor what order, what causes, and what leads to
honey bee mite
- causes varroosis
○ sucks hemolymph
- most pronounced economic impact on beekeeping industry
- contributing factor to colony collapse disorder
- Transmit viruses and bacteria
