Evaluation of Wuchereria bancrofti infection in Culex pipiens fatigans in Rangoon, Burma.

In the past, several indices have been proposed to evaluate the threat of vectors to the community. Such indices, if accurately determined, could serve to assess the effectiveness of vector control campaigns. In this paper, a "risk of infection" index is introduced for the case of urban filariasis transmitted by Culex pipiens fatigans in Rangoon, Burma. This index is directly proportional to the three principal parameters that determine the extent of transmission-namely, the biting density of the vector, the proportion parous to total biting, and the proportion infective to total parous; all these parameters are easily determined from biting catches. Examples of the use of the index are given and it is noted that, in areas where conditions are not favourable to the vector throughout the year, or where the speed of development of the parasite in the vector may not be constant, these variables must be taken into account in calculating the index.