Critical time:
Autumn/winter
General:
This parasite is found in cattle, sheep and goats and is seen in the rumen (“groot maag”) and the reticulum (“ruitjiespens”).
The life-cycle moves from the ruminant to a small snail. The snail sheds the next stage which attaches itself to grasses on or near the surface of water. Once the cow/sheep eats the contaminated grass the animal becomes infected.
This means dams, streams, “vleis”, leaking water troughs are a serious source of infection esp. when water levels start dropping in the dry season. Once the nighttime temperatures drop below 10 C regularly the snails cannot survive.
Diagnosis:
It is difficult to diagnose conical fluke infection. If given enough time animals should show a poor appetite, weight loss and diarrhoea but often (esp. in veld cattle) animals are just found dead. Faecal samples give an accurate diagnosis as worm eggs can be seen under the microscope. Post mortems also give an accurate answer.
Control:
This is a host (gasheer) specific parasite ie if the specific snails are absent there will not be conical fluke. Where there is a problem, water cribs should be kept clean and leak proof; grazing animals in swampy areas should be avoided; fencing off dams/streams can be considered. The use of molluscocides is controversial due to the effect on the environment.
Treatment:
Currently double doses of Tramizan/Nemafluke 72hrs apart are recommended to control mature and immature parasites. Dosing is recommended +/- in June. Terenol is also used.