Benign leptospirosis: first reported outbreak in British Isles due to strains belonging to the Hebdomadis serogroup of Leptospira interrogans.

The clinical and epidemiological features associated with the first reported outbreak in the British Isles of benign anicteric leptospirosis, due to strains belonging to the hebdomadis subgroup, are described. Four cowherdsmen working in two dairy farms in Surrey developed a febrile illness which was not associated with jaundice, but aseptic meningitis was a feature. Microscopic agglutination tests with formolized antigen suspensions revealed a significant rise in the agglutinin titres against various serotypes belonging to the hebdomadis serogroup of Leptospira interrogans. The probable source was eventually traced to the cattle, which showed serological evidence of infection with the same serogroup.