Difference between revisions of "Fasciolosis"
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| − | == | + | == Fasciolosis == |
The adult liver fluke, ''Fasciola hepatica'', lives in the bile ducts of a wide range of animals, including sheep, cattle, rabits and, less often, horses. It can infect humans causing a painful abdominal disease. The intermediate host in the UK is a mud snail, ''Lymnaea truncatula''. Significant economic losses occur in western parts of the British Isles. Deaths, clinical and subclinical disease in cattle is confined to a younger stock. Fasciolosis is a seasonal disease with more serious outbreaks occurring in some years than in others. A similar but slightly larger species, ''F. gigantica'', occurs in wetter tropical regions. | The adult liver fluke, ''Fasciola hepatica'', lives in the bile ducts of a wide range of animals, including sheep, cattle, rabits and, less often, horses. It can infect humans causing a painful abdominal disease. The intermediate host in the UK is a mud snail, ''Lymnaea truncatula''. Significant economic losses occur in western parts of the British Isles. Deaths, clinical and subclinical disease in cattle is confined to a younger stock. Fasciolosis is a seasonal disease with more serious outbreaks occurring in some years than in others. A similar but slightly larger species, ''F. gigantica'', occurs in wetter tropical regions. | ||
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| + | === Ovine Fasciolosis === | ||
| + | '''Acute fasciolosis''': sudden death; normally September-November; enlarged pale, friable, haemorrhagic liver with more than 1000 immature flukes in liver parenchyma. (In cattle, acute disease is rarely seen). | ||
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| + | '''Sub-acute fasciolosis'': rapid weight-loss over 1-2weeks; October-December; normochromic anaemia; enlarged liver with large haemorrhages; more than 500 flukes - 50:50 immature and adult. | ||
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| + | '''Chronic fasciolosis''': progressive weight-loss over weeks or months; January-March; anaemia normochronic, leads to hypochromic; hypoalbuminaemia, which leads to oedema; small distorted cirrhotic liver; enlarged bile ducts; more than 250 adult flukes. (In cattle, calcification of bile ducts leads to 'pipe-stem' liver). | ||
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| + | '''Sub-clinical effects''': | ||
| + | *In sheep, fleece weight and fibre quality are affected even by small fluke burdens. There is some evidence that reproductive performance (number of lambs born and growth-rate of lambs) is inversely influenced, but this has not been well documented. | ||
| + | *Liver conemnations cause economic losses at slaughter. (Note: in beef cattle - sub-clinical infection leads to longer finishing times to slaugter weight, reduced carcass value). | ||
| + | *In dairy cows - reduced milk yield (and quality). | ||
Revision as of 14:49, 22 December 2008
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Fasciolosis
The adult liver fluke, Fasciola hepatica, lives in the bile ducts of a wide range of animals, including sheep, cattle, rabits and, less often, horses. It can infect humans causing a painful abdominal disease. The intermediate host in the UK is a mud snail, Lymnaea truncatula. Significant economic losses occur in western parts of the British Isles. Deaths, clinical and subclinical disease in cattle is confined to a younger stock. Fasciolosis is a seasonal disease with more serious outbreaks occurring in some years than in others. A similar but slightly larger species, F. gigantica, occurs in wetter tropical regions.
Ovine Fasciolosis
Acute fasciolosis: sudden death; normally September-November; enlarged pale, friable, haemorrhagic liver with more than 1000 immature flukes in liver parenchyma. (In cattle, acute disease is rarely seen).
'Sub-acute fasciolosis: rapid weight-loss over 1-2weeks; October-December; normochromic anaemia; enlarged liver with large haemorrhages; more than 500 flukes - 50:50 immature and adult.
Chronic fasciolosis: progressive weight-loss over weeks or months; January-March; anaemia normochronic, leads to hypochromic; hypoalbuminaemia, which leads to oedema; small distorted cirrhotic liver; enlarged bile ducts; more than 250 adult flukes. (In cattle, calcification of bile ducts leads to 'pipe-stem' liver).
Sub-clinical effects:
- In sheep, fleece weight and fibre quality are affected even by small fluke burdens. There is some evidence that reproductive performance (number of lambs born and growth-rate of lambs) is inversely influenced, but this has not been well documented.
- Liver conemnations cause economic losses at slaughter. (Note: in beef cattle - sub-clinical infection leads to longer finishing times to slaugter weight, reduced carcass value).
- In dairy cows - reduced milk yield (and quality).