Parasites (Internal)
See also Ostertagiosis, liver fluke infection, paramphistomiasis, tapeworm
Faecal egg counts and differential larval counts are a guide to the size and type of worm burden. The faecal egg count depends on a number of factors including faecal consistency and bulk, host resistance, stage of pregnancy and effects of lactation, as well as the parasite involved and whether the parasites are sexually mature.
The history should provide details of all recent anthelmintic treatments and flock management, e.g. stocking rates, pasture availability, swampy areas, paddock movement, etc.
For further information on internal parasites follow these links
Primefacts and other information on sheep internal parasites
Primefact - 'Cattle worm control - the basics'.
Pathology and diagnosis of internal parasites in ruminants. Love SCJ, Hutchinson GW (2003). In Gross Pathology of Ruminants, Proceedings 350, Post Graduate Foundation in Veterinary Science, University of Sydney, Sydney;Chapter 16:309-338
Diagnosis
Clinical signs, faecal egg count, larval cultures and total worm count.
Specimens required
Live animal
- At least 30 g of faeces collected from the rectum, submitted in a screw-top jar filled to capacity for egg count and larval culture. In flock or herd investigations, samples should be collected from 10 or 20 animals showing evidence of parasitism.
WormTest is a convenient system for collecting and submitting faecal samples to the laboratory.
- For F. hepatica in cattle serum sample chilled for serology
Milk ELISA testing for liver fluke is currently (2004) under validation; check with your veterinary laboratory for availability.
Dead animal
Preferably -
- The whole gastrointestinal tract (double bagged in strong clear plastic) submitted unopened, but tied off, either chilled or frozen for parasitological examination.
Alternatively -
- Aliquot samples of 1 L from the stomach and small intestines, submitted in a 5% formalin solution for parasitological examination.
- The abomasum and intestine, submitted chilled or frozen for examination for immature parasites.