PLASMA ENZYME LEVELS IN RUMINANTS INFECTED WITH FASCIOLA-HEPATICA

Clinical studies on sheep infected with Fasciola hepatica have shown that there is a good correlation between the level of infestation and bodyweight, as well as with erythrocyte numbers, packed cell volume, haemoglobin and plasma protein values. Changes in these parameters first occur about 8 weeks after infection by which time a considerable amount of damage might well have been inflicted upon the liver as a result of the migrations of immature flukes. Experiments with calves artificially infected with 650 to 1000 Fasciola hepatica metacercariae have shown that liver damage due to fluke migrations can be detected at an earlier stage by measuring the plasma activities of appropriate enzymes of intermediary metabolism. In unmedicated calves marked elevations in the plasma levels of these enzymes were observed from as early as 3 weeks after infection, with maximum activities recorded 7 to 8 weeks later. Administration of diamphenethide to such calves at 3, 5 or 7 weeks after infection resulted in changes in plasma enzyme levels suggesting cessation or prevention of active liver damage. Further study of changes in plasma levels of enzymes and other parameters in animals subject to continual infection is needed to clarify the clinical potential of these findings. © 1979.