Frequency of typhoon occurrence accounts for the Poisson distribution of human leptospirosis cases across the different geographic regions in the Philippines

Objective: To study the distribution of human leptospirosis cases across the different geographic regions in the Philippines in 2015-2017 and to determine the relationship between the frequency of typhoon occurrence and human leptospirosis cases. Methods: Information on the frequency of leptospirosis cases and typhoon occurrence across the different regions in the Philippines from 2015 to 2017 was retrieved from the databases of the Department of Health and the Philippine Atmospheric, Geophysical, and Astronomical Services Administration, respectively. Descriptive measures on the prevalent cases and occurrence of typhoons across the different regions were summarized. Linear regression analysis was employed to establish the functional relationship between leptospirosis cases and typhoon occurrence. The distribution of human leptospirosis cases was assessed using the Poisson distribution. Results: The frequency of typhoon occurrence accounted for the significant linear variation in the geographic distribution of human leptospirosis cases in the Philippines (P<0.001). Moreover, the human leptospirosis cases obeyed a Poisson distribution (λ=6.89, P