title: Molecular xenomonitoring using mosquitoes to map lymphatic filariasis after mass drug administration in American Samoa.
abstract: BACKGROUND
  Mass drug administration (MDA) programs have dramatically reduced lymphatic filariasis (LF) incidence in many areas around the globe, including American Samoa. As infection rates decline and MDA programs end, efficient and sensitive methods for detecting infections are needed to monitor for recrudescence. Molecular methods, collectively termed 'molecular xenomonitoring,' can identify parasite DNA or RNA in human blood-feeding mosquitoes. We tested mosquitoes trapped throughout the inhabited islands of American Samoa to identify areas of possible continuing LF transmission after completion of MDA.
  
  
  RESULTS
  Mosquitoes were collected using BG Sentinel traps from most of the villages on American Samoa's largest island, Tutuila, and all major villages on the smaller islands of Aunu'u, Ofu, Olosega, and Ta'u. Real-time PCR was used to detect Wuchereria bancrofti DNA in pools of ≤ 20 mosquitoes, and PoolScreen software was used to infer territory-wide prevalences of W. bancrofti DNA in the mosquitoes. Wuchereria bancrofti DNA was found in mosquitoes from 16 out of the 27 village areas sampled on Tutuila and Aunu'u islands but none of the five villages on the Manu'a islands of Ofu, Olosega, and Ta'u. The overall 95% confidence interval estimate for W. bancrofti DNA prevalence in the LF vector Ae. polynesiensis was 0.20-0.39%, and parasite DNA was also detected in pools of Culex quinquefasciatus, Aedes aegypti, and Aedes (Finlaya) spp.
  
  
  CONCLUSIONS
  Our results suggest low but widespread prevalence of LF on Tutuila and Aunu'u where 98% of the population resides, but not Ofu, Olosega, and Ta'u islands. Molecular xenomonitoring can help identify areas of possible LF transmission, but its use in the LF elimination program in American Samoa is limited by the need for more efficient mosquito collection methods and a better understanding of the relationship between prevalence of W. bancrofti DNA in mosquitoes and infection and transmission rates in humans.
authors.affiliation: Division of Community and Natural Resources, American Samoa Community College, Pago Pago, American Samoa.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Schmaedick
authors.affiliation: Department of Entomology, College of Agriculture, University of Kentucky, Lexington, Kentucky, United States of America.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Koppel
authors.affiliation: Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America.
authors.forename: Nils
authors.initials: N
authors.lastname: Pilotte
authors.affiliation: Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America.
authors.forename: Melissa
authors.initials: M
authors.lastname: Torres
authors.affiliation: Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Williams
authors.affiliation: Department of Entomology, College of Agriculture, University of Kentucky, Lexington, Kentucky, United States of America.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Dobson
authors.affiliation: Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Lammie
authors.affiliation: Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Kimberly Y
authors.initials: KY
authors.lastname: Won
mesh_terms: D000330:Aedes / Q000469:parasitology*; D000818:Animals; D003465:Culex / Q000469:parasitology*; D018509:DNA, Helminth / Q000032:analysis / Q000235:genetics; D004605:Elephantiasis, Filarial / Q000188:drug therapy / Q000453:epidemiology / Q000635:transmission; D005369:Filaricides / Q000627:therapeutic use; D006801:Humans; D017720:Molecular Epidemiology; D014958:Wuchereria bancrofti / Q000145:classification / Q000235:genetics*
chemical_list: D018509:DNA, Helminth; D005369:Filaricides