Myocastor coypus as a reservoir host of Fasciola hepatica in France

To clarify the role of the nutria Myocastor coypus in the epidemiology of d omestic fasciolosis in Loire-Atlantique (department of western France), 438 nutrias were trapped in 9 humid areas of the department and 304 nutrias we re trapped in 3 farms where Fasciola hepatica was present; all animals were necropsied. Liver flukes were found in 160 nutrias: 38 nutrias randomly ta ken in the department (8.7%) and 122 trapped in fasciolosis areas (40.1%). The average parasitic burden was 5.7 flukes per nutria. Sixty-five percent of the liver flukes measured more than 18 mm (size of sexual maturity). The coproscopic examinations carried out on 144 infected nutrias showed that 9 0% of the infected nutrias shed fluke eggs. The hatching rate was 39.6%. Tw o groups of 100 Lymnaea truncatula snails, originating from 2 different pop ulations, were exposed to F. hepatica miracidiae hatched from eggs collecte d from infected nutrias. The prevalence of the infection was 74% and 58.6% in the 2 groups of snails. The average redial burden was 6.2 rediae per sna il. The total number of metacercariae was 72.4 metacercariae per snail prod ucing cercariae. Two groups of 5 sheep were orally infected by 150 metacerc ariae of nutria or sheep origin, respectively. The installation rates of F. hepatica in sheep were respectively 31.6% and 29.6% for the two groups. Sp ecific antibody kinetics of sheep were similar whether the metacercariae we re of nutria or sheep origin. M. coypus allows the complete development of F. hepatica and releases parasitic elements that are infective for domestic ruminants. Because of its eco-ethologic characteristics, the nutria could be a potential wild reservoir of F. hepatica in France.