The Migration of Infective Larvae of Wuchereria bancrofti within the Mosquito Host and Their Rate of Escape under Laboratory Conditions

Abstract

Culex quinquefasciatus [female] [female] were infected with the periodic strain of W. bancrofti and were exd. at 2-day intervals from 16 1/2 to 301/2 days after the infected blood meals. Counts were made of the number of larvae recovered from the proboscis, head, thorax, and abdomen of each mosquito. 209 dissections were made, with an average of 26 at each interval. The av. number of larvae per mosquito decreased from 48.7 at 161/2 days to 8.8 at 301/2 days, with the greatest rate of loss occurring between 181/2 days and 261/2 days after infection. The av. number of larvae recovered from the various sections of the body indicated that the usual migration path of mature larvae is from thorax to abdomen and then to head and proboscis. It was concluded that the loss of larvae occurred through the proboscis, either from feeding on cotton soaked with sugar soln. or from rupture of proboscides when the latter contain too many larvae. This loss was greatest during the week following attainment of the infective larval stage.