Research of Leptospira serovar Hardjo in the genital and urinary tracts of sheep. Abstracts

Ovine has been known to be a reservoir of Leptospira hardjo like cattle (Amaddeo D. et al. 1988; Andreani E. et al. 1974; Autorino G.L.etal. 1990; Cousins D.V. etal. 1989; Ellis W.A. et al. 1981). In both species renal spirochetal localization was demonstrated, but it is still unclear if Leptospira locate in genital organs of sheep'. In Italy, knowledge of L. hardjo diffusion in sheep are almost scanty. Therefore a seroepidemiological survey was carried out in order to evaluate the diffusion of L. hardjo infection and to verify the presence of renal and/or genital carriers of L.hardjo in sheep. At this purpose, 1630 blood serum samples from sheep of 107 flocks were tested by MAT for the presence of L.hardjo antibodies. Considering as positive titers > 1:100,68 samples (4.17%) gave positive responses. Ten of these positive animals belonged to a 66 heads flock and the remaining 58 animals belonged to a 111 heads flock, both placed in the province of Pisa. All these animals were raised on the same pasture with cattle. Bacteriological examinations were carried out on urine samples, kidney, uterus and salpinges of 4 seropositive animals from the first flock, in order to isolate L.hardjo. Spirochetes were recovered from 3 of the 4 urine samples and from 3 renal tissue cultures, but the microrganisms were not isolated from uterus or salpinges. Immunohistochemical tests on kidney, uterus and salpinx tissue samples confirmed the results of bacteriological examinations. The results of this research seem to confirm that sheep are not genital carriers of L.hardjo. In order to corroborate this hypothesis, an experimental infection of ewes and rams with L.hardjo has been recently realized