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High molecular prevalence of Leishmania in phlebotomine sand flies fed on chicken blood in Brazil

Author:
de Sousa Ferreira, Tauana, Timbó, Renata Velôzo, Minuzzi-Souza, Thaís T.C., de Almeida Rocha, Douglas, Neiva, Mariana, de Albuquerque Ribeiro, Joana, de Almeida, Paulo Silva, Hecht, Mariana, Nitz, Nadjar, Gurgel-Gonçalves, Rodrigo
Source:
Veterinary parasitology 2018 v.259 pp. 80-84
ISSN:
0304-4017
Subject:
Leishmania infantum, Lutzomyia longipalpis, blood, blood meal, cats, chickens, dogs, females, genes, humans, leishmaniasis, melting, mitochondrial DNA, monitoring, ribosomal DNA, risk, synanthropes, wet season, Brazil
Abstract:
Leishmaniases are endemic in Brazil, where Leishmania infantum has been detected in humans, dogs, cats, and phlebotomine vectors. Monitoring synanthropic vector populations is critical for leishmaniasis control-surveillance in such transmission-prone areas. Here, a suite of molecular approaches were used to assess Leishmania infection prevalence and to identify blood-meal sources in a large sample of sand flies collected in anthropic environments of a Leishmania-transmission area in Mato Grosso do Sul State (Rio Verde de Mato Grosso municipality), Central-West Brazil. We sampled sand flies monthly (January-June 2014 and 2016) in one peri-domestic site within each of six neighborhoods with recent records of human visceral and/or tegumentary leishmaniasis. kDNA-qPCR plus rDNA ITS-sequencing were used to detect and identify Leishmania in pooled female sand flies. Individual engorged females (n = 58) were used for blood-meal analyses through High-Resolution Melting (HRM) targeting the mtDNA cytb gene. Overall, 90.5% of 420 CDC trap-nights yielded vectors, for a total catch of 24,989 sand flies. We sub-sampled and identified 3088 sand flies of 12 species, including 2775 Lutzomyia longipalpis (the most abundant species at all sampling sites) and 297 Nyssomyia whitmani. Female sand flies (n = 1261) were grouped in 159 pools, of which 92 Lu. longipalpis (minimum infection rate [MIR] 8%) and 7 Ny. whitmani pools (MIR 7%) were Leishmania kDNA-positive. Most positive Lu. longipalpis were collected in the 2016 rainy season. Sequencing confirmed L. infantum in Lu. longipalpis samples. HRM analyses identified chicken DNA in 57 sand flies (98.3%), 37 of which were Leishmania DNA-positive (64.9%); human blood was found in just one (Leishmania-negative) female. Our data show ongoing risk of L. infantum transmission to humans in the study area, where Leishmania-infected sandfly vectors are common and heavily rely on chicken blood in the peri-domestic environment.
Agid:
6107772