Eurytrema spp are important zoonotic flatworms which are endemic in Asia and cause hepatic cancer in humans. Cattle are considered incidental hosts and rarely cause disease in this host.
Species which are pathogenic in cattle include:
- Eurytrema pancreaticum
The life cycle involves intermediate snail hosts (Lymnaea spp) with infective metacercariae that are normally eaten by pigs, but can be consumed by cattle during grazing. The adult fluke usually reside in the peripheral small bile ducts of the liver and produce chronic inflammation of the bile duct, bile duct dilatation, mechanical obstruction, and bile duct wall thickening. Once mature, the flukes pass eggs into the bile, which are passed out in the feces and contaminate pasture. Other animals, as well as humans become infected by eating uncooked beef.
Clinical signs are often vague in cattle and laboratory testing for Eurytrema eggs and elevated bilirubin and liver enzyme on blood tests may help determine a diagnosis. In acute infections, acute hepatitis is a common sequelae, which usually leads to cirrhosis in more chronic cases. Bile duct walls may become greatly thickened and calcified and adult flukes may also be found in aberrant sites such as the lungs.
Diagnosis is based on presenting clinical signs, isolation of the parasite eggs in feces, identification of adult flukes in the liver and laboratory analysis of parasite for identification. Commercially available ELISA are also available in some countries.
Control of this parasite is through use of molluscicides to control the snail (intermediate host) as well as flukicidal drugs such as triclabendazole, closantel, moxidectin plus triclabendazole and oxyclozanide.
Herd milk sample monitoring is an effective way of assessing control of this parasite.
- Roy B & Tandon V (1992) Seasonal prevalence of some zoonotic trematode infections in cattle and pigs in the north-east montane zone in India. Vet Parasitol 41(1-2):69-76
- Merck Vet Manual
- Kuerpick B et al (2012) Bulk milk-estimated seroprevalence of Fasciola hepatica in dairy herds and collecting of risk factor data in East Frisia, northern Germany. Berl Munch Tierarztl Wochenschr 125(7-8):345-350