World Health Organization : Regioinal Office for Africa ; Year 1993 ; Africa Region, 6403, Ex.196, No. 03.02: A Serological Survey on Arborvirus Infections in Kenya

By World Health Organization

Description
Medical Reference Publication

Excerpt
Filarial mosquitos are dissected as a routine in many parts of the world, yet little information is available about the natural mortality of these vectors. The results of dissections are recorded as the percentage of female mosquitos containing filarial larvae at all stages of development-the infection rate-and the percentage of females containing mature infective filarial larvae-the infectivity rate. The proportion of mosquitos carrying infective parasites can be used, as Macdonald (1957) has shown, to estimate mosquito survival. For example, in Cz~lexfa tigans, if females carrying infective larvae of Wzrclzereria bancrofti can be assumed to have survived at least ten days, which is about the minimum period frcm ingestion of the microfilariae to the development of the infective stage, then the probability of survival over one day is given by lo\/ of the ratio of the number of mosquito~ w ith infective larvae to the total number of infected mosquitos. But few mosquitos survive long enough for the conlplete development of the parasite, or infective larvae nlay be lost when the mosquito feeds, and the number of mosquitos collected with infective filarial larvae is usually low, often too low to provide reliable estimates of inortality by this method alone.

Table of Contents
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