Molecular xenomonitoring for Wuchereria bancrofti in Culex quinquefasciatus in two districts in Bangladesh supports transmission assessment survey findings

摘要

Author summary To ensure elimination of lymphatic filariasis, efficient surveillance methods are needed. While some available methods rely on the detection of Wuchereria bancrofti microfilaria, antigen or antibody in human blood samples, molecular xenomonitoring can identify parasite DNA in vector mosquitoes. We collected the main vector of lymphatic filariasis in Bangladesh, Culex quinquefasciatus mosquitoes, in two districts in Bangladesh to see if W. bancrofti could be detected. One of the districts never had evidence of widespread transmission but borders another district where transmission was most recently detected. The other district had previously had W. bancrofti transmission, but after 12 rounds of mass drug administration, had been deemed to have little to no ongoing transmission. In each district, traps were set at 180 sites to collect mosquitoes. Over ten thousand Cx. quinquefasciatus mosquitoes were collected, but none of them tested positive for presence of W. bancrofti. The practice of trapping mosquitoes was feasible for the national program to execute, and the absence of infected mosquitoes suggests that parasite rates are nearing zero.