Pigs Flashcards
What is the superfamily of ascaris suum?
Ascaridoidea
What is the life cycle of ascaris suum?
Eggs excreted in faeces.
Earthworms/dung beetles ingest ascarid eggs whilst feeding on the soil.
L2 encysts in the tissue of the paratenic host.
Pigs are infected by ingesting eggs or an infected paratenic host.
L2 burrows into the intestinal wall, enters the hepatic portal system and travels to the liver. L2-L3.
L3 migrates in the bloodstream to the lungs via venous system.
4-6 days after infection, L3 migrates up the bronchial tree to the pharynx and are swallowed.
L3 moults to adults in the small intestine.
What is the infective stage of ascaris suum?
Egg containing L2.
What is the pre-patent period of ascaris suum?
6-8 weeks.
What is the size of the male and female worms of ascaris suum?
Male: 15-25cm
Female: <40cm
What is the pathogenesis of ascaris suum?
Liver migrating larvae causes milk spot. So the liver is condemned at slaughter.
Adult worms can cause obstruction in large numbers and a poor feed conversion.
What are the clinical signs of ascaris suum?
Transient pneumonia in young. So can exacerbate other causes of pneumonia.
Heavy infections can predispose to bacterial/viral infections.
Significant impact on growth rates.
Life threatening in heavy infections.
What is the epidemiology of ascaris suum?
Females are prolific and eggs can survive for years in the environment.
Piglets are infected early birth.
Highest prevalence: 3-6 months.
Immunity in adults.
Seasonal occurrence in temperature regions - higher in summer.
How can ascaris suum be diagnosed?
Faecal egg count.
Observation of large worms in the faeces.
Post-mortem: milk spots and adult worms in the intestine.
Why might pigs have a low egg count in their faeces?
They are coprophagic - eat their own poo.
How can ascaris suum be controlled?
Treatment for secondary bacterial invaders, which are necessary during the respiratory phase of infection.
Anthelmintics.
Hygiene to prevent egg spread contamination.
What is the superfamily of trichuris suis?
Trichuroidea
What is the life cycle of trichuris suis?
Eggs are excreted in faeces. L1 develops in the egg.
Eggs are ingested and hatch in the intestine.
L1 penetrates mucosa in ileum, caecum, colon and moults to L5.
1/3 of adults emerge.
2/3 remain embedded in the mucosal layers.
What is the pre-patent period of trichuris suis?
7-10 weeks
What are the clinical signs of trichuris suis?
Severe cases:
Diarrhoea
Anaemia
Anorexia
What is the super family of trichinella spiralis?
trichinelloidea
What is the life cycle of trichinella spiralis?
No free living stage.
Adults in SI, L1 travels via blood to muscles where they encyst.
Host is consumed, then the L1 develops to adults.
The adults in the IH will produce L1, which encysts in the muscle of the IH.
How can domestic pigs be infected with trichinella spiralis?
Eating uncooked food waste, rodents and other tails.
How can humans be infected with trichinella spiralis?
Eating muscle with encysted larvae
What is the pathogenesis of trichinella spiralis in young pigs and humans?
Young pigs: diarrhoea, inappetence and weakness.
Humans: diarrhoea, fever, muscle pain, dyspnoea.
How can trichinella spiralis be diagnosed?
Digestion of small portions of the diaphragm muscle in pepsin/HCl.
Examination of sediment for L1.
ELISA for mass screening at slaughter houses.
How can trichinella spiralis be controlled?
Boil food waste before feeding to pigs.
Meat inspection.
Eliminate rodents.
Freezing/cooking of meat to kill L1.
