Detection of multiple circulating Leishmania species in Lutzomyia longipalpis in the city of Governador Valadares, southeastern Brazil

Abstract

28Background 29 Leishmaniasis encompasses a group of diverse clinical diseases caused by protozoan 30 parasites of the Leishmania genus. This disease is a major public health problem in 31 the New World affecting people exposed in endemic regions. The city of Governador 32 Valadares (Minas Gerais/Brazil) is a re-emerging area for visceral leishmaniasis, with 33 191 human cases reported from 2008 to 2017 and a lethality rate of 14.7%. The 34 transmission of the parasite occurs intensely in this region with up to 22% of domestic 35 dogs with positive serology for the visceral form. Lu. longipalpis is one of the most 36 abundant sand fly species in this area. Despite this scenario, so far there is no 37 information regarding the circulating Leishmania species in the insect vector Lutzomyia 38 longipalpis in this focus. 39 Methodology/Principal Findings 40 We collected 616 female Lutzomyia longipalpis sand flies between January and 41 September 2015 in the Vila Parque Ibituruna neighborhood (Governador 42 Valadares/MG), which is located on a transitional area between the sylvatic and urban 43 environments with residences built near a preserved area. After DNA extraction of 44 individual sand flies, the natural Leishmania infections in Lu. longipalpis were detected 45 by end-point PCR, using primers derived from kDNA sequences, specific for L. 46 (Leishmania) or L. (Viannia) subgenus. The sensitivity of these PCR reactions was 0.1 47 pg of DNA for each Leishmania subgenus and the total infection rate of 16.2% (100 48 positive specimens). Species-specific PCR detected the presence of multiple 49 Leishmania species in infected Lu. longipalpis specimens in Governador Valadares, 50 including L. amazonensis (n=3), L. infantum (n=28), L. (Viannia) spp. (n=20), 3 51 coinfections with L. infantum and L. (Viannia) spp. (n=5), and L. (Leishmania) spp 52 (n=44). 53 Conclusions 54 Our results demonstrate that multiple Leishmania species circulate in Lu. longipalpis 55 in Governador Valadares and reveal a potential increasing risk of transmission of the 56 different circulating parasite species. This information is a key factor for planning 57 surveillance and effective control strategies against leishmaniasis in this endemic 58 focus. 59 60 Author summary 61 Leishmaniasis is a neglected tropical disease transmitted to mammals by the 62 bite of sand flies infected with parasites of the Leishmania genus. This disease affects 63 millions of people in various regions of the world, including Brazil. The municipality of 64 Governador Valadares (Minas Gerais/Brazil) is a re-emergent focus of intense 65 transmission of leishmaniasis, with a high number of human cases and a high 66 prevalence of infected domestic dogs. To develop better leishmaniasis control 67 strategies for the region, we performed a surveillance study of Lu. longipalpis, the main 68 vector of visceral leishmaniasis in Brazil, and identified circulating species of 69Leishmania in this insect vector. We estimate that the natural infection rate of Lu. 70 longipalpis...