Studies on the Seasonal Patterns of Rodent, Flea and Plague Outbreaks in the Western Usambara Mountains, North-East Tanzania

Abstract

Field and commensal rodents were live-trapped at the villages  of Gologolo, Shume-Nywelo  and  Gemai from December 1983 to November 1984; Their flea ectoparasites were collected, processed, identified and counted.  The rodent carcase were serologically examined for specific plague antibodies, and antigens, and bacteriologically examined for bipolar-stained bacilli. A total of 1758 traps were set during the 12 months period and 924 animals were caught.  From these, 1037 Feas were collected making an average total flea index of 1.1 fleas per animal.  R. rattus, P. natalensis and L. flavopunctatus comprised the largest proportions of the rodent population while D. lypusus, C. calceatus and X. brasiliensis were the most abundant flea species. Both rodents and fleas were most abundant in December - January. Rodent populations were least dense from May to September while fleas were least abundant from June to November and highly dense from December to May. Human plague was most active from November to March, while rodents contained plague antibodies every month except May and June with a peak in September