Persistence of Brugia malayi DNA in vector and non-vector mosquitoes: implications for xenomonitoring and transmission monitoring of lymphatic filariasis.
Xenomonitoring (detection of filarial larvae or their DNA in mosquitoes) is a sensitive marker for assessing the endemicity of filariasis and a useful tool for evaluating elimination programs. To examine the fate of microfilariae (mf) and filarial DNA in vector competent and non-competent mosquito strains, we compared the detection of Brugia malayi parasites by dissection and by quantitative real-time polymerase chain reaction (PCR) in three different mosquito strains. We conclude that PCR is much more sensitive than dissection for detecting filarial larvae, especially their remnants in mosquitoes. However, parasite DNA can be detected in both vector and non-vector mosquitoes for two weeks or longer after they ingest mf-positive blood. Thus, although xenomonitoring with vector and non-vector mosquito species may be a sensitive method for indirectly detecting filarial parasites in human populations, positive test results for parasite DNA in mosquitoes do not necessarily prove that transmission is ongoing in the study area.
Fischer
Peter
P
Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA. pufische@im.wustl.edu
Erickson
Sara M
SM
Fischer
Kerstin
K
Fuchs
Jeremy F
JF
Rao
Ramakrishna U
RU
Christensen
Bruce M
BM
Weil
Gary J
GJ
D000330:Aedes / Q000469:parasitology*; D000818:Animals; D017178:Brugia malayi / Q000235:genetics / Q000302:isolation & purification*; D003465:Culex / Q000469:parasitology*; D018509:DNA, Helminth / Q000032:analysis*; D004605:Elephantiasis, Filarial / Q000175:diagnosis / Q000635:transmission*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity
D018509:DNA, Helminth