During the period from July 10-26, 1984, 33 cases of serologically confirmed leptospirosis occurred in a small town in central Italy. The fatality rate, including the deaths of two unconfirmed cases, was 8.6% (3 of 35). Based on serologic evidence, the infection was caused by leptospires of the serogroup Australis. Epidemiologic study showed that the patients contracted the infection by drinking water from a fountain. The source of leptospiral contamination was probably a hedgehog trapped in a reservoir of water not in use but still connected to the water system of the fountain.

This investigation is the first nationwide survey on the circulation of leptospira infections in human beings in Italy. In nine out of twenty Italian regions, representative samples of the population were investigated for the presence of leptospira infections. Unexpectedly, leptospira infections were found to be widespread, the number of cases being much higher than the diagnosed clinical cases. There were found to be high, medium, and low risk areas. On the whole, the risk for the rural population was no higher than the risk for urban dwellers; leisure activities, contact with animals and residence on the plain versus residence in the hills were important risk factors. There was an unidentified risk factor in urbanites which was absent in the rural population. A changing pattern in infecting serovars was observed, with infections from serogroups Sejroe, Javanica and Australis prevailing over infections from the Icterohaemorrhagiae and Bataviae serogroups, which were the main agents of human leptospirosis during the 1950s. The mechanisms of these changes, the need for epidemiological surveys and improved diagnostic methods of screening are discussed.

Sera from Somalis of both sexes between the ages of 16 and 60 were examined for leptospiral agglutinins. 37% of 105 apparently healthy individuals living in the arid Mogadishu area were positive, as were 64% of 107 schistosomiasis patients living in two villages on the Shabeele River (50.5% over-all). Pools of sera from similar subjects, as well as leprosy patients living on the Juba River and patients in Mogadishu hospitals with suspected viral hepatitis showed a similar prevalence rate of 56%. These figures are higher than prevelance rates for leptospiral antibodies generally found in other parts of the world, and in part may be related to the nomadic, cattle-driving existence common in Somalia. The titres of 11.2% of the positive sera examined singly indicated recent infection. Approximately twice as many subjects from the river villages as from the Mogadishu area were positive for more than one serovar, and a greater number of serovars were recorded from the villages. Antibodies to bratislava serovar, not previously recorded in Africa, were found in 57% of positive subjects, showing the highest prevalence rate among the investigated serovars. Co-antibodies to saprophytic Leptospira biflexa serovars were found in many of the sera.

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