Wuchereria bancrofti in Culex mosquitoes before and after mass treatment. Dissection results were pooled in 3-month intervals and are plotted for each of the four sentinel sites. The percentage of mosquitoes harboring any stage larvae is plotted in the lighter bars. The percentage of mosquitoes carrying L3 larvae is plotted in the darker bars. Significant changes from the August-October pre-treatment interval are indicated with an asterisk. Note that different scales are used for each sentinel site.