MST 1 - Important Parasites

What are the characteristics of bovicola ovis

• Found on wool close to skin

• Biting louse

• See reduced numbers in summer

• Eggs can’t survive in cold temps or in rain or in high humidity

• Photophobic

What is the pathogenesis of bovicola bovis

Feeds on stratum corneum → causes hyper sensitivity, itching, rubbing → pulled wool appearance

What management options can you treat bovicola ovis with

Put sheep out in the sun for UV/exposure, shear the sheep in warmer months

What chemical treatment options can you use t treat bovicola bovis

You can apply a backline formula of thiacloprid up to 7 days off shearing and can also use avermectin as a backline treatment as well but shouldn’t use together to avoid resistance development

What parasite causes queensland itch

Culicoides brevitarsi

Where do you see the lesions in horses with queensland itch

Around the tail, rump, back, poll and ears

What preventative treatment can you use on horses with queensland itch

Stabling horses at night since culiocoides is crepsucular, cleaning and maintenence to remove cattle dung breeding and repellent usage.

Which stage of the oestridae flies causes issues and why?

The larval stage as they are endoparasites and because the adults have vestigal mouthparts and therefore can’t feed

What are the three types of horse bots in australia

Gasterophilus intestinalis, Gasterophilus nasalis, Gasterophilus haemorrhoidalis

Where would you find the eggs of the three gasterophilus flies in a horse

Intestinalis → eggs laid on front body

Nasalis → eggs laid inbetween mandibles

Haemorrhoidalis → eggs laid around lips

What colour are the eggs for the horse bots in australia

Intestinalis = yellow

Nasalis = pale

Haemorrhoidalis = black

Where would you find the larvae G. intestinalis and nasalis and how long do they remain in he horse

Intestinalis larvae are found in the horse's stomach, while nasalis larvae are found in the duodenum

Remain for 9-12 months

How would you treat horse bot infestations

Use of macrocylic lactones such as ivermectin or moxidectin and treat them in the winter when flies are absent

What clinical signs might you see with the sheep nasal bot

Clinical signs include nasal discharge, sneezing, lack of feeding, head shaking and potential secondary infections.

How would you treat oestrus ovis infestations

Oestrus ovis infestations can be treated with products containing macrocyclic lactones like ivermectin or moxidectin. Treatment is most effective when aimed at the larvae stages. You can also treat with a trematocide worm drench

Where are the larvae of oestrus ovis found

The larvae of Oestrus ovis are found in the nasal cavity of infected sheep.

What clinical signs do you see in cattle affected with haematobia exigua

Painful bites, irritation, loss of condition, restlessness, and reduced weight gain, reduced milk production

How would you effectively control Haemtobia exigua

Using a tunnel trap in the summer, ear tags with insecticides and sprays such as organophosphates or synthetic pyrethroids. Can also use ivermectin in cattle dung or dung beetles in cattle dung

Which fly species causes primary fly strike

Lucilia cuprina

Which fly species can cause secondary fly strike

Chrysomya rufifiacies, calliphora augur and calliphora stygia

What clinical signs can you see with fly struck sheep

Signs of fly strike in sheep include a foul odor, inflammation, and visible maggots in affected areas, along with loss of wool, skin damage, and possible secondary infections. Affected sheep may also show signs of distress and reduced feeding.

What is the pathogenesis of fly strike

Need presence of faeces and urine → olfactory stimuli present → females attracted → babies attracted to proteinaceous exudate on skin

What do signs preceed body strike in sheep

Fleece rot or dermatitis, prolonged wetting of skin causing keratin lifting.

What is the difference in the conditions that can predispose breech strike vs body strike in sheep

Breech strike is often associated with dirty wool around the hindquarters due to fecal contamination and also wrinkles, while body strike can occur in areas where moisture and heat promote skin breakdown but also due to having sway back and wrinkles

What host measures could you take to control flystrike

Mulesing, tail docking, crutching and breeding for better fleece

What fly control measures can you take to prevent fly strike

Burning carrion to prevent breeding grounds, fly traps, chemicals such as imidacloprid, ivermectin and spinosads

Who is the screw worm fly and why are the a threat in australia

Chrysomya bezzina which will kill animals due to loss of tissue leading to threats against livestock and native species. They are also very had to eradicate in australia and therefore could see a decrease in food producton

How long is life cycle for haemtobia exigua

7-11 daysH

How long is the life cycle for lucilia cuprina

17 days in summer

Where do argas persicus ticks lay their eggs

Around cracks and crevices of fowl/poultry

What is the lifespan of argas persicus

eggs can survive for 3 months, nymphs for 1 year, adults for up to 3 years.

What clinical signs do you see with hosts infested with argas persicus

Common signs include anemia, depression, reduced egg production, and skin irritation. Severe infestations can lead to significant weight loss and even death in affected birds.

How do you treat argas persicus infestations

Coumaphos, malathion or permethrin and need to treat both host and housing

What effect do you see of hosts with ixodes holocylcus infestations

Ascending flaccid paralysis and irritation, intense vasoconstriction and paralysis of respiratory muscles later on

Which animals are most susceptible to the holocyclotoxin

Sheep, dogs and cats are more susceptible and can be killed by only 1 tick compared to sheep and foals which needs 4 ticks

How do you treat ixodes holocyclus infestations

Remove the tick as soon as possible and can use an acaricidal wash. upport therapy is also recommended.

What is the typical lifecycle of rhipicephalus australis

The lifecycle of Rhipicephalus australis typically involves four stages: egg, larva, nymph, and adult. Each stage requires a blood meal from a host to develop into the next stage. The adult usually drops off after 18-37 days to lay eggs before dying

How does temperature change rhipicephalus australis development

Winter suppresses tick development whilst rain and tropical weather promote tick development

What clinical signs do you see in cattle with rhipicephalus australis

• rritation - ticks removed by grooming

• anaemia - each tick takes 1-5 ml blood

• anorexia (reduced appetite)

• damage to hides - loss of 25% of value

• reduced growth rate and milk production

How would you manage your cattle with rhipechaplus australis infestations

Rotating cattle and spelling paddocks longer than 4 weeks to break the lifecycle but could be up to 11 weeks in winter

Which cattle breed is more resistant to rhipicephalus australis

Bos indicus type cattle

What chemical treatment could you use on cattle with rhipicephalus australis

Fluazuron as a growth regulator and ivermectin