Seasonality of sand flies (Diptera: Psychodidae) and Leishmania DNA detection in vector species in an area with endemic visceral leishmaniasis

Abstract

BACKGROUND Leishmaniases are a serious health problem in southeast Brazil, including the city of Belo Horizonte (BH), Minas Gerais state (MG), where there are high rates of incidence and mortality due to visceral leishmaniases. BH is divided into nine sanitary districts (SD) of which one, the Venda Nova SD, was selected for this study because it has high rates of positivity for canine leishmaniasis and high incidence of human leishmaniasis.OBJECTIVES This study aimed to survey the sand fly fauna in Venda Nova SD from August 2011 to July 2013 and perform a descriptive analysis of the vector population.METHODS The sampling was carried out using automatic HP light traps at all covered areas of the Venda Nova SD, in a total of eighteen light traps. Sampled specimens were identified following Galati (2003), and females were submitted to molecular techniques for the detection and identification of Leishmania DNA. A simple environmental description was done for it area and Kernel estimation was used to infer vector density for each study site.FINDINGS A total of 2,427 sand fly specimens belonging to eight species and five genera were collected of which 95.3% were Lutzomyia longipalpis. The seasonal variation curve was delineated by this species. Lu. longipalpis was the most abundant at all collection points and in all months of the study, and exhibited a natural infection rate of 1.01% for Leishmania infantum and 1.77% for Leishmania braziliensis.MAIN CONCLUSIONS The results show the presence and adaptation of Lu. longipalpis to the anthropic environment of BH and reinforces its role as the main vector of L. infantum in the region.

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

“…Lu. longipalpis is the main vector of L. infantum in Brazil [6], however, reports of PCR detection of other Leishmania species in this sand flies have been described in several studies [33, 38, 43, 44]. In agreement with our results, these studies described the association of Lu.…”

“…longipalpis with the parasites of Leishmania genus was 16.2%, being 13% with Leishmania subgenus and 4% with Viannia subgenus. These rates are higher than those found in other regions of Brazil [33, 38, 43, 44, 48], which may contribute to the high risk of Leishmania infection in Governador Valadares. In studies carried out in Brazil, the natural infection rate of Lu.…”

“…The use of PCR for detection of Leishmania DNA in sand flies is a useful technique for the identification of putative vectors in different geographical areas [33, 36-39]. Some targets used to analyze the infection in sand flies are ITS1 [33, 37, 38] and kDNA [36, 40, 41].…”

“…In agreement with our results, these studies described the association of Lu. longipalpis with L. infantum, and also with L. amazonensis [43] and L. braziliensis (or a parasite belonging to Viannia subgenus) [33, 38, 43, 44]. Mixed infections of L. (Leishmania) sp.…”

Rural area of the Brazilian Pantanal wetlands associated with the occurrence of anti-<i>Leishmania</i> spp. antibodies in dogs

“…Therefore, the presence of agriculture and the proximity of dogs to forests, wastelands, and locations that have undergone recent environmental changes also contribute to the vector´s development. The urbanization of AVL results from anthropogenic environmental alterations and the rapid and intense migration of rural populations to urban peripheries lacking proper infrastructure, including the concurrent interaction of sylvatic reservoirs and domestic dogs (DIAS et al, 2003;SARAIVA et al, 2017).…”