title: Distribution of Lutzomyia longipalpis chemotype populations in São Paulo state, Brazil.
abstract: BACKGROUND
  American visceral leishmaniasis (AVL) is an emerging disease in the state of São Paulo, Brazil. Its geographical expansion and the increase in the number of human cases has been linked to dispersion of Lutzomyia longipalpis into urban areas. To produce more accurate risk maps we investigated the geographic distribution and routes of expansion of the disease as well as chemotype populations of the vector.
  
  
  RESULTS
  A database, containing the annual records of municipalities which had notified human and canine AVL cases as well as the presence of the vector, was compiled. The chemotypes of L. longipalpis populations from municipalities in different regions of São Paulo State were determined by Coupled Gas Chromatography - Mass Spectrometry. From 1997 to June 2014, L. longipalpis has been reported in 166 municipalities, 148 of them in the Western region. A total of 106 municipalities were identified with transmission and 99 were located in the Western region, where all 2,204 autochthonous human cases occurred. Both the vector and the occurrence of human cases have expanded in a South-easterly direction, from the Western to central region, and from there, a further expansion to the North and the South. The (S)-9-methylgermacrene-B population of L. longipalpis is widely distributed in the Western region and the cembrene-1 population is restricted to the Eastern region.
  
  
  CONCLUSIONS
  The maps in the present study show that there are two distinct epidemiological patterns of AVL in São Paulo State and that the expansion of human and canine AVL cases through the Western region has followed the same dispersion route of only one of the two species of the L. longipalpis complex, (S)-9-methylgermacrene-B. Entomological vigilance based on the routes of dispersion and identification of the chemotype population could be used to identify at-risk areas and consequently define the priorities for control measures.
authors.affiliation: Superintendência de Controle de Endemias, Secretaria de Estado da Saúde, Mogi Guaçu, São Paulo, Brazil.
authors.forename: Claudio
authors.initials: C
authors.lastname: Casanova
authors.affiliation: Departamento de Biologia Animal, Instituto de Biologia, UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Fernanda E
authors.initials: FE
authors.lastname: Colla-Jacques
authors.affiliation: Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, United Kingdom.
authors.forename: James G C
authors.initials: JG
authors.lastname: Hamilton
authors.affiliation: Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: Reginaldo P
authors.initials: RP
authors.lastname: Brazil
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Shaw
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D004285:Dogs; D008401:Gas Chromatography-Mass Spectrometry; D040362:Geographic Information Systems; D006801:Humans; D007303:Insect Vectors / Q000737:chemistry / Q000254:growth & development* / Q000469:parasitology; D007898:Leishmaniasis, Visceral / Q000453:epidemiology / Q000635:transmission*; D008297:Male; D011576:Psychodidae / Q000737:chemistry / Q000254:growth & development* / Q000469:parasitology