A comparison of molecular markers to detect Lutzomyia longipalpis naturally infected with Leishmania (Leishmania) infantum

Abstract

The aim of the present study was to detect natural infection by Leishmania (Leishmania) infantum in Lutzomyia longipalpis captured in Barcarena, state of Pará, Brazil, through the use of three primer sets. With this approach, it is unnecessary to previously dissect the sandfly specimens. DNA of 280 Lu. longipalpis female specimens were extracted from the whole insects. PCR primers for kinetoplast minicircle DNA (kDNA), the mini-exon gene and the small subunit ribosomal RNA (SSU-rRNA) gene of Leishmania were used, generating fragments of 400 bp, 780 bp and 603 bp, respectively. Infection by the parasite was found with the kDNA primer in 8.6% of the cases, with the mini-exon gene primer in 7.1% of the cases and with the SSU-rRNA gene primer in 5.3% of the cases. These data show the importance of polymerase chain reaction as a tool for investigating the molecular epidemiology of visceral leishmaniasis by estimating the risk of disease transmission in endemic areas, with the kDNA primer representing the most reliable marker for the parasite.

Contribution to the Knowledgment of Feeding Habbits of Lutzomyia (Lutzomyia) Longipalpis (Lutz & Neiva, 1912) in Association to Natural Infection by Leishmania (Leishmania) Infantum Chagasi (Cunha & Chagas, 1937)

“…In this study, it was possible to detect the natural infection of L. (L.) longipalpis by L. (L.) infantum chagasi in Araguaína and Sobral, which are areas of intense transmission of AVL, with rates of 4.9% and 9, 8% respectively. In Fortaleza, a minimum natural infection rate of 3.7% was detected [61]. These results reinforce the practicality of the use of molecular techniques in the identi cation of natural infection, since it is known that infection rates are low in nature, even in areas endemic for AVL.…”

“…Diagnostic assays using PCR have been developed based on different molecular targets such as ribosome minor subunit genes, mini-exon gene spacer sequences, single-copy nuclear sequences such as the DNA polymerase alpha gene, but the minicircle kDNA are the ones that present the highest sensitivity for detection of Leishmania [22,[58][59][60][61][62][63].…”

Eco-epidemiological aspects, natural detection and molecular identification of Leishmania spp. in Lutzomyia reburra, Lutzomyia barrettoi majuscula and Lutzomyia trapidoi

“…En el presente trabajo, se utilizó el gen espaciador interno de la transcripción del ARN ribosómico, unidad I (ITS1), propuesto recientemente para una detección más sensible de Leishmania spp. que otros marcadores (22), en especial, cuando se debe detectar de forma rápida la leishmaniasis cutánea (23) y genotipificar especies neotropicales del parásito (24).…”

Visceral Leishmaniasis and Natural Infection Rates of Leishmania in Lutzomyia longipalpis in Latin America

“…On the other hand, high rates of natural infection were observed by Freitas-Lidani et al [88] and Saraiva et al [104], with 8.6 and 19%, respectively, in Pará and Minas Gerais states (North and Southeast regions of Brazil). Both rates were determined using molecular approaches by individual vector analysis.…”

“…Multiple molecular markers from nuclear and kinetoplast Leishmania DNA have been used to detect naturally infected phlebotomines, including the miniexon-derived RNA gene, rRNA gene, repeated genomic sequences and the kinetoplast minicircle DNA (kDNA), which is present at thousands of copies per cell [84][85][86][87]. These molecular markers are assessed by PCR methods using specific primers to amplify conserved regions, with kDNA amplification having greater reliability as a marker for the parasite when compared to miniexon and 18S rRNA [88]. Currently, PCR assays are able to detect and identify the parasite (L. (L.) i. chagasi) and vector (Lu.…”