Anopheline ecology and malaria transmission at a new irrigation project area (Bargi Dam) in Jabalpur (Central India).

Anopheline ecology and malaria transmission were studied in a newly irrigated area of the Bargi Project, District Jabalpur, Madhya Pradesh, Central India. Observations were made for 2 years (1993-95) in 10 villages along the Bargi irrigation canal, which are situated between 44 km (head end of canal) and 78 km (tail end of canal) from the dam site. Anopheles annularis was the predominant species in the head-end villages and its abundance was directly related to the opening of the canal, whereas Anopheles culicifacies was the most abundant species in tail-end villages, where irrigation is limited. Anopheles culicifacies showed 2 typical peaks not related to canal irrigation. Site-related differences in species prevalence were significant in both immatures and adults. Malaria infection was due to Plasmodium vivax and Plasmodium falciparum. The annual parasite incidence in children and adults was significantly higher in head-end villages (>4-fold) as compared to that in tail-end villages. However, seasonal trends in the prevalence of P. falciparum and P. vivax were the same in each group, with some fluctuations. In this study, preliminary results of the investigation are presented, demonstrating the trends in anopheline ecology and parasite prevalence in relation to the dynamics of irrigation development.