Preliminary studies on the prevalences of natural fasciolosis in cattle, sheep, and the host snail (Galba truncatula) in north-eastern Algeria.

Three series of investigations on natural infections with Fasciola hepatica were carried out in north-eastern Algeria): (1) on different samples from cattle and sheep slaughtered at Constantine and Jijel from 1994 to 1996, (2) from 31 cattle- and sheep-breeding farms from 1999 to 2001, using serology on blood samples, and (3) on overwintering Galba truncatula from four populations, in 2002 and 2003. Significantly higher prevalences of fasciolosis were found in the cattle and sheep from Jijel (27.0% in slaughtered cattle and 27.3% in cattle from farms, compared to 9.1% and 6.3%, respectively, in cattle from Constantine). No significant differences in the prevalences were recorded between 1994 and 1996 and 1999 and 2001 for each species of ruminant, whatever the department considered. The infection rates for overwintering snails were also higher in the two populations from Jijel compared with those from the department of Constantine (a mean of 4.6-5.9% instead of 2.6-3.1%)). These results may be explained by the climatic conditions in the department of Jijel (an annual rainfall of 750-900 mm instead of 350 mm at Constantine), and the mode of anthelminthic treatment (the periods of treatment would be inappropriate in the case of Jijel).