3.2. Influence of rainfall
The epidemics of leptospirosis occurred during years of
increased annual rainfall. The highest number of reported
cases occurred in 1985, 1986 and 1995, which corresponded
to the years with the highest rainfall index. A positive
association was found between annual case numbers and
year (P = 0.059) and rainfall (P < 0.001) and the interaction
summary term for year and rainfall (P < 0.001). The semipartial
correlation between rainfall and cases was 0.9691
(P < 0.001), confirming the influence of increased rainfall
with increased case numbers of leptospirosis