Reduced-Cost Xenomonitoring for Lymphatic Filariasis

Nils Pilotte and Steven Williams of Smith College in the U.S. along with Lisa Reimer at the Liverpool School of Tropical Medicine in the United Kingdom are developing a simple and inexpensive approach to monitor diseases caused by parasites that thrive in mosquitos based on detection in mosquito feces. Current approaches for disease surveillance are expensive, insensitive, or labor intensive, and are generally unsuitable for the areas in which they are needed most, including where disease incidence has decreased. This proposed so-called molecular xenomonitoring approach overcomes these hurdles, in part by avoiding the need for human sampling, and because it can be adapted to increase throughput. In Phase I, they demonstrated proof-of-principle that very low levels of parasitic DNA could indeed be extracted from mosquito fecal samples and then detected by PCR, and also adapted a simple test-strip detection method that could be used in low-resource field settings. They also developed a mosquito trap from a two-liter soda bottle containing a simple carbon dioxide-producing solution and sugar, and demonstrated its ability to attract mosquitos and isolate their feces in a field setting in Trinidad, albeit with modest yields. In Phase II, they will further optimize their detection method and the traps, and perform preliminary field tests in malarial and filarial endemic locations in the Philippines, Ghana, and Haiti.