Seasonal variation of flea population and its relationship with small mammal hosts in sub-urban Yangon

ABSTRACT

Monthly flea and small mammal surveys covering three seasons (cool dry, hot dry and monsoon) were carried out at three townships in Yangon. From more than 400 small ammmals captured, two species of fleas totalling about 700 were collected and identified as Xenopsylla astia and Xenopsylla cheopis. General flea inded was found to be highest in May (dry hot) with 6.7 and lowest in November (cool dry) with 0.09. Total ratio of collected X. astia and X. cheopis was foung to be about 21. However, host-vector specificity was pronounced between these two species especially on B. bengalensis. The great majority of X. astia were infested on B. bengalensis (p < 0.05) and the majority of X. cheopis were infested on other above ground species namely Rattus exulans, R. rattus and Suncus murinus mainly in dry hot seasons. Several factors which might govern the host-vector specificity are outlined. Dur to the host-vector specificity, the limitations and the use of various flea indices are discussed and suggestions are made for a proper surveillance system. The prospect of the timely flela control program as a preventive plague control measure is also discussed.