Parasitic Gut diseases II Flashcards
What is toxocara spp. ?
- Large white round worms, 7-18 cm in length
- Adults in small intestine
- Three main species:
What are the three main species of toxocara?
Toxocara canis – dog
» Toxocara cati (or mystax) – cat
» Toxascaris leonina – fox
What are the two definitions of a paratenic host?
- Host in which no development of the parasite occurs
- Hosts which are not neccesary for the parasites life cycle but can act as a reservoir of infection
What are the differences between T.Cati and T.leonina
T.Cati is-
* has paratenic hosts (rodents, earthworms, birds etc.)
* Migratory if eggs ingested, non-migratory after TM infection or paratenic host ingestion
* Eggs hatch in the stomach then migrate via the liver, lungs, trachea and back to the stomach
* no prenatal infection
T.leonina
* has no migration of larvae
* following ingestion, larvae enter the intestinal wall and remain there for two weeks
What are the clinical consequences of Toxicara?
All species
* Mild to moderate infections – no clinical signs
* May be potbelly, failure to thrive, vomiting,
diarrhoea, particularly in puppies & kittens
* Due to absorption of nutrients & damage to
the intestine lining
* Obstruction of intestinal lumen or
intussusception
T.canis -> causes larval discharge
Where can toxicara eggs be found?
in the faeces
What is the difference between the eggs of T.canis and T. leonina?
Small finger-like process on the tail of male T. canis but not Tx. leonina
What is the epidemiology of toxicara?
Very widespread due to
* female worms being fecund (producing a lot of offspring)
* larvae in the tissue of bitches is not susceptible to antithelmintics
* The eggs are resistant to climatic extremes
What is the epidemiology of T.cati?
- Reservoir – larvae in tissue of dam & in paratenic hosts
- Patent infections more common in young cats
- Prevalence 10-20% in adult cats – continued shedding through life of cat
What is the epidemiology of Tx. leonina?
- Infection mainly through eggs, but can occur
» through paratenic hosts
What are the four clinical conditions found in humans with toxocara?
mainly in children
1) Visceral larval migrans
2) Ocular toxocariasis – visual impairment
3) Covert toxocariasis
4) Cerebral toxocariasis
How long are hookworms and where can they be found?
Up to 20 mm long and the adults are found in the small intestine
What are the hookworm species that can infect dogs and cats?
Uncinaria stenocephala (temperate regions)
A. braziliense (tropical & subtopical regions)
What are the clinical consequences of hookworms?
- Diarrhoea, weight loss and anaemia, may be acute or chronic signs
- Ancylostoma caninum more serious
- Disease most common in younger animals
What are the most common hookworm species in the UK?
Uncinaria stenocephala & A. tubaeforme
What kind of animal is most affected by hookworms?
Young animals most affected, adults pass eggs in faeces
What is the diagnosis for hookworms?
clinical signs, haematology, coproantigen tests, hookworm
eggs in faeces (in pups may be severe signs before eggs in faeces)
What are hookworms in humans associated with?
Poor sanitation and hygeine
What are the symptoms of hookworms in humans?
Anaemia, abdominal pain, wasting & stunting in children
What canine and feline hookworm can infect humans?
A. braziliense
What hookworm species are common in asia?
A. ceylanicum and A.
caninum
What is the pathogenesis of dipylidium caninum?
- they are adult worms and non-pathogenic
- shed segments may cause anal discomfort and itching
What is the diagnosis for dipylidium caninum?
presence of segment (proglottid) on coat around peritoneum,
can break open & see egg packets under a microscope
What does dipylidium caninum require for transmission?
Requires the presesnce of adult fleas or biting lice
How would you diagnose taenia in dogs and cats?
The infections are generally asymptomatic
Heavy infection is a sign of gut problems
The diagnosis is- presence of tapeworm segments in perianal
area or proglottids, or eggs in faece
What kind of parasite is echinococcus?
a cestode parasite
What are the two main species of echinococcus?
Echinococcus granulosus
and E. multilocularis (subartic)
What is the diagnosis of eccinococus in definitive hosts?
- Observe adult worms on necropsy
- Copro-antigen ELISA
- Copro-PCR
How can you control toxocara and hookworm?
- You cant eliminate infection only reduce the burden and prevent transmission to people
- de-worming of pets
- pick up dog faeces
What are three ways you can control fleas and Dipylidium caninum
- Adulticide
- Environmental control
- cleaning the environment
How can you control echinococcus?
- Regular treatment (praziquantel) in endemic areas
- Deworming frequency dependent on hunting/feeding
habits - Found at meat inspection in abattoirs - risk based
assessment - Prevention of access to offal/carcasses
What is the typical toxicara lifecycle for a dog under 5 weeks?
- eggs are ingested in the environment
- larvae are released in the intestine
- eggs are then passed on in the faeces
- the PPP= 4-5 weeks
What is the typical toxicara lifecyle for a dog over 5 weeks? (not pregnant)
- When the larvae are released into the intestine they can then migrate to other tissues (formation of tissue cysts)
What is the typical toxicara lifecyle for a dog over 5 weeks? (pregnant)
Tissue cysts can be reactivated
* This means that puppies can become infected (milk -> puppy)
What is a proglottid?
The segment of an adult tapeworm, each one contains a sexually mature system
What are the 5 responsible uses of parsiticdes in dogs and cats?
- Work with clients to prevent and check for parasites
- Understand the potential risks to animals and humans
- Take a risk-based approach to prescribing medication
- Ensure appropriate use
- Record and Monitor use
