Trichuroidea Parasite Superfamily

Trichinella Larvae encysted in muscle.

An important superfamily for both humans and birds. 

Trichuris- egg. 

Trichuris

'Whipworm.' 

• Found in the large intestine.
• Characteristics eggs which are highly resistant. 
• Ruminants, dogs & pigs.
• Common.
• Resilient to many anthelmintics.
• Not very pathogenic in the UK.
• Egg containing L1 is the infective stage. 

Capillaria 

'Hairworm.' 

• Many species & host specific.
• Highly pathogenic in birds.
• Ulceration of the upper GI tract, inflammation, weight loss & death. 

Three poultry species:

1. C.obsignata has a direct life cycle.
2. C.contorta and C.caudinflata has an indirect life cycle and an earthworm intermediate host. It is a cause of disease in free range birds. 

Control= BZ in feed. 

Trichinella 

• Important zoonosis.
• Wide range of carnivore host.
• Humans, pigs & horses.
• Wild life reservoirs.
• Worldwide. 
• Eradicated from the UK.

No eggs or larvae in faeces and no free living stages. 

• Adults in the small intestine.
• Small & short lived.
• Females are larviparous.
• L1 are born and pass through the wall of the SI where they migrate to the muscles and encyst.
• Transmission occurs when muscle cysts are eaten.
• L1 released, mature to adults, reproduce and die. 

No disease in domestic animals but serious, fatal human disease. Fever, oedema, muscle pain, peri-orbital oedema, and myocarditis. People become infected through eating undercooked, contaminated meat. Outbreaks have been associated with smoked sausage, horse meat, and infected wild animals. The main source of infection is pigs and horses, as well as game meat. 

Control

• Meat inspection- automated muscle digestion systems.
• Cooking and freezing.
• Important wildlife reservoirs.
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