Seasonal prevalence of Anopheles dirus and malaria transmission in a forest fringed village of Assam, India.

Seasonal abundance of Anopheles dirus (s.l.) and malaria prevalence in an isolated forest fringed village was monitored at monthly intervals during August 1995 to July 1996. An. dirus was the only vector species detected during the study period. Its density pattern showed distinct seasonality with the peak occurring in the month of July and very low number during cool dry months. Positive correlation (r = 0.721) was found between the density of An. dirus and the amount of rainfall occurring two weeks prior to the collections. Overall sporozoite rate of 1.6% and parous rate of 64.7% were found in the study. Malaria transmission closely followed the density pattern of An. dirus and was seasonal with slide positivity rate and P. falciparum percentage of 47 and 83% respectively. Mean malaria prevalence was higher (p < 0.05) in females.