F. Kramer et T. Schnieder, Investigations on the intermediate host of Fasciola hepatica using a DNA-probe for establishing an epidemiologic diagnostic method, PRAKT TIER, 80(6), 1999, pp. 520
In an epidemiological study from May to November 1997 intermediate hosts of
F. hepatica have been collected on F. hepatica positive farms. After prepa
ration the DNA was examined for possible infection in a DNA dot blot with a
Fasciola specific DNA probe. The suitability of the probe for an epidemiol
ogical diagnostic method was examined. Based on a repetitive gene segment o
f F. hepatica (Kaplan et al. 1995) the probe was specific for Fasciola and
did not show any crossreactivity with other tested trematodes or the interm
ediate host Lymnaea truncatula. The prevalences in the population of the in
termediate host of this study were higher than the data of a number of othe
r studies. In the months with the highest prevalences they were ranging fro
m about 11 to 48 per cent (May) and from about 6 to 38 per cent (August). S
even to 90 intermediate hosts would have been enough in these months in ord
er to detect an infection with F. hepatica in the population of the interme
diate host with 99 per cent security. The most ideal conditions for a rando
m epidemiological diagnostic test are May and August/September for the coll
ection of the intermediate host and suggesting an unideal condition with a
prevalence of 2 per cent in the population of the intermediate host, a volu
me of 228 samples in order to diagnose an infection of the intermediate hos
ts and to detect an infection risk for the final host without examination o
f him.