Control of Roundworms (Toxocara spp.) Flashcards
What are the definitive hosts for T. canis, and T. cati?
Canis: canine nematode dog and red fox
Cati: feline nematode, Cats and other felids
Where do Toxacara live?
In the small intestine
What are some of the signs of infection in animals?
Typically no clinical signs
Adults worms survive 4-6
Diarrhoea, pot belly, resp signs (pups)
Some worms can be spontaneously expulsed -6 weeks
How are dogs/foxes infected?
- Swallowing Toxocara eggs from environment
- Eating Toxocara larvae in raw meat
- Larvae passed to offspring in utero nursing
Many pups are already born with it:(
Whats the basic life cycle of the roundworm?
- larvae migrates from liver—> lung—-> trachea (hepato tracheal migration)
- Larvae mature whilst migrating, swallowed by host
- Adult worm develops in small intestine, eggs shed in faeces
this is typical in young naive dogs <6m old
Whats the infection in older dogs (life cycle)? if larvae ingested.
- Laevae ingected in contaminiated raww meat
- No migration needed larvae ready to develop to adult small intestines
- Patent infection- eggs shed in faeces
Whats the infection in older dogs (life cycle)? If infected eggs ingested.
1.Infective eggs ingested from environemnt.
2. Larvae hatch out, but not usual migration route, stop at the lungs.
What happens in a toxocara infection of pups?
Larvae migrate from tissues of bitch to the uterus in pregnancy
Some may migrate to mammary glands of bitch (5%)
pups commonly born with migrating larvae in tissues, shed eggs in faeces at 2-3 weeks of age
Nursing bitch can develop patent infection- shed eggs
What are some of the features of toxocara eggs that are important from a epidemiology perspective?
Each female worm produces - 200k eggs/day
Eggs in faeces contaminate environment
Larval development to L3in egg (embryonation)- becomes infective in 4-weeks
Hardy shell- can last for years depending on conditions
Eggs survival highest in tropical regions - why?
Warm temperature: the eggs require warmth to developin the infective stage
High humidity, help prevent the eggs from drying out
What are the different treatments used to control Toxocara?
Treating pregnant queens: Emodepside spot-on approx. 7 days before expected birth (reduce transmission via milk)
Treating pregnant bitch: Macrocyclic lactones on 40th+55th day of pregnancy or fenendazole daily from the 40th day of pregnanzy continuing to 2 days postpartum
Treating puppies: Treat from 14 days of age and kittens from 3 weeks of age
Repeat at fortnightly intervals until 2 weeks after weaning and then monthly up to the age of six months (treat the mother at the same time as the young)
Treating adult animals: 2-4 times/year (or carry out faecal exam)- risk assessment
Whats the most common drug given to treat Toxocara?
Antiparasite drugs: Anthelmintics
The most common is Benzimidazole anthelmintics
