Relationship between microfilarial density, the number of microfilariae ingested by mosquitoes and the proportion of mosquitoes with larvae

Publisher Website
Google Scholar
Abstract
The proportion of susceptible Culex pipiens of the genotype sb/sb which had developing or infective Brugia phangi filarial larvae depended on the microfilarial density in the blood. An optimum density of 10 mff/mm3 produced, on average, 80% susceptibility in the mosquitoes. It is thought that the failure to achieve 100% infections may be due to incomplete penetrance and expression of sb (filarial susceptibility to B. pahangi in the C. pipiens complex). The incomplete penetrance in the phenotypically refractory mosquitoes of the sb/sb genotype may be due to the absence of modifying genes favoring filarial susceptibility. C. pipiens takes up the microfilariae of Wuchereria bancrofti and B. pahangi in different patterns. About 1.8 times more W. bancrofti microfilariae are ingested than expected from the density of circulating microfilariae. A correlation between the square root of the mean observed microfilariae .**GRAPHIC**. and the square root of the mean expected microfilariae .**GRAPHIC**. is represented by the equation, .**GRAPHIC**. = 1.27 .**GRAPHIC**. + 0.29. Fewer B. pahangi microfilariae are ingested than expected (0.31 times expected). A correlation between the square root of the mean observed microfilariae .**GRAPHIC**. and the square root of the mean expected microfilariae .**GRAPHIC**. for B. pahangi is represented by the equation .**GRAPHIC**. = 0.067 .**GRAPHIC**. - 0.54. Chemotropism to mosquito salivary secretion, either positive or negative, might explain the different patterns observed in the uptake of the microfilariae of W. bancrofti and B. pahangi by C. pipiens. Mosquitoes fed via an artificial membrane took up very variable numbers of microfilariae, the variation being similar to that observed in donor-fed mosquitoes.

This publication has 10 references indexed in Scilit: