Malaria transmission in the Tarai, Naini Tal District, Uttar Pradesh, India.

A study of the problems of malaria transmission in the Tarai of Naini Tal District, Uttar Pradesh, India, has been made by a WHO Malaria Control Demonstration Team operating in the area between 1949 and 1952.Earlier investigators of malaria transmission in the area had concluded that the fever season coincided with the pre-monsoon period; that Anopheles minimus was the chief vector; and that A. fluviatilis could be dismissed as a zoophilic non-vector.As a result of the team's malariometric and entomological surveys, the following conclusions have been reached: malaria transmission takes place throughout the year; A. minimus is virtually non-existent and plays no part in transmission; A. fluviatilis, the primary vector, is responsible for transmission in the pre- and post-monsoon periods; A. culicifacies, the secondary vector, is responsible for transmission in the monsoon period (July-September).The results of precipitin tests on A. fluviatilis-which gave a gross anthropophilic index of over 40%-indicate that the A. fluviatilis found in this region of India is a mixture of both anthropophilic and zoophilic races; further studies are required to substantiate this theory.