Absence of epidemicity of severe leptospirosis in Barbados.

The possibility of micro-epidemics of severe leptospirosis occurring on the island of Barbados was investigated by examining the space-time clustering of the disease in 212 laboratory-confirmed cases admitted to Queen Elizabeth Hospital, Bridgetown, over a 7-year period. A series of 109 patients with symptoms compatible with leptospirosis but shown to be otherwise by laboratory examination were also examined for comparison. No significant space-time clustering was found among the leptospirosis cases, indicating no evidence for micro-epidemics. By comparison, statistically significant clustering was apparent among the smaller non-leptospirosis series. Possible explanations for the absence of observed micro-epidemics of leptospirosis are discussed.