Morphological variability in Fasciola hepatica eggs in ruminants, rodents and lagomorphs

The length and width of 1297 Fasciola hepatica eggs shed in cattle hosts, 3 37 in sheep and 199 in nutria, were measured from several parts of France. The data were compared with those obtained from other studies in Spain, Fra nce (where rats were also investigated), Germany and the Netherlands. One w ay analysis of variance and discriminant analysis were used to assess diffe rences between host origins. The distribution of length and width of eggs w ere analysed using skewness and kurtosis Fisher coefficients. The eggs reco vered from sheep, cattle, rodents and lagomorphs were different in size: th e eggs found in rodents (length L x width W in mu m: 8592) and lagomorphs ( L x W in mu m: 9100) were smaller than those found in sheep and cattle (L x W in mu m: 10,000). These morphological differences in F. hepatica eggs we re host-induced in rats (L x W in mu m: 9709 in cattle to 8949 in rats) and rabbits (L x W in mu m: 9709 in cattle to 8432 in rabbits). These differen ces in size of eggs might correspond to their being less able to develop in to miracidia in less frequent hosts such as rodents and rabbits.