Detection of Wolbachia pipientis, including a new strain containing the wsp gene, in two sister species of Paraphlebotomus sandflies, potential vectors of zoonotic cutaneous leishmaniasis

Individual, naturally occurring Phlebotomus mongolensis and Phlebotomus caucasicus from Iran were screened for infections with the maternally inherited intracellular Rickettsia-like bacterium Wolbachia pipientis via targeting a major surface protein gene (wsp). The main objective of this study was to determine if W. pipientis could be detected in these species. The sandflies were screened using polymerase chain reaction to amplify a fragment of the Wolbachia surface protein gene. The obtained sequences were edited and aligned with database sequences to identify W. pipientis haplotypes. Two strains of Wolbachia were found. Strain Turk 54 (accession EU780683) is widespread and has previously been reported in Phlebotomus papatasi and other insects. Strain Turk 07 (accession KC576916) is a novel strain, found for first time in the two sister species. A-group strains of W. pipientis occur throughout much of the habitat of these sandflies. It is possible that Wolbachia is transferred via horizontal transmission. Horizontal transfer could shed light on sandfly control because Wolbachia is believed to drive a deleterious gene into sandflies that reduces their natural population density. With regard to our findings in this study, we can conclude that one species of sandfly can be infected with different Wolbachia strains and that different species of sandflies can be infected with a common strain.

Dual culture method to determine the relationship of gut bacteria of sandfly (Phlebotomus argentipes) with promastigotes of Leishmania donovani.

A simple dual culture agar plating technique has been developed and evaluated for its efficiency in determining the relationship of gut bacteria of sandfly with Leishmania donovani promastigotes. There are about twenty morphologically distinct bacterial colonies have been isolated from the gut homogenate of Phlebotomus argentipes. In dual culture method, each bacterial isolate was inoculated in one half of the plate and the promastigotes of Leishmania was inculcated in the other half by streaking. After incubation, the type of association was determined based on the presence or absence of promastigotes colonies. The reliability of this method was compared with broth dilution method in 96 well plate.

O papel dos equídeos na ecologia da Leishmaniose visceral no Estado da Bahia, Brasil / The role of horses in the ecology of visceral leishmaniasis in Bahia, Brazil

Nas áreas endêmicas dos municípios de Jequié e Jacobina, Estado da Bahia, Brasil, realizou-se uma pesquisa sobre o papel dos eqüídeos na ecologia da leishmaniose visceral. Quinhentos e dois eqüídeos das espécies Equus caballus, Equus asinus e Equus caballus x Equus asinus, que vivem nessas áreas, foram estudados através de diversos métodos para diagnóstico e isolamento de leishmanias e correlacionados com casos humanos e com a vetora Lutzomyia longipalpis. Foram realizados os seguintes exames nesses animais: esfregaço e cultura de sangue periférico; esfregaços e culturas de biópsias do lábio inferior e os testes imunológicos : ELlSA, TRALd, Dot-blot. Os testes imunológicos apresentaram os seguintes percentuais de positividade: 19,32 por cento para o ELlSA, 40 por cento para o TRALd e 13,72 por cento para o Dot-blot. Esta alta prevalência de soro positividade, indica a presença de anticorpos específicos contra a Leishmania e a existência de eqüídeos infectados nessas áreas. Contudo, não foi possível isolar Leishmanias desses animais. Por outro lado, quatro Equus asinus inoculados com formas promastigotas de Leishmania chagasi e acompanhados por um período de 10 a 12 meses, foram também submetidos a todos os exames acima mencionados e mais biopsia e estudo da medula óssea, do baço e do fígado. O parasito foi demonstrado no fígado de dois destes eqüídeos experimentalmente infectados, através do exame histopatológico, após a necropsia dos animais. Seus testes de ELlSA e TRALd foram positivos nos O, 10° e 12° meses após a inoculação. Assim sendo, tanto os animais que adquirem naturalmente a infecção nas áreas endêmicas, quanto os inoculados experimentalmente com elevado número de promastigota, são capazes de debelar a infecção espontaneamente. Conclui-se que os eqüídeos são desprovidos de importância como reservatórios na cadeia de transmissão da leishmaniose visceral, embora tenham importância epidemiológica como fonte de alimentação sangüínea e na manutenção da população de Lutzomyia longipalpis.

Bacillus thuringiensis var. israelensis as a microbial control agent against adult and immature stages of the sandfly, phlebotomus papatasi under laboratory conditions

The laboratory treatment of adult and immature stages of Phlebotomus papatasi by the bacterial insecticide Bacillus thuringiensis var. israelensis was carried out. Different concentrations of Bti mixed with fructose and glucose were assayed against the adult sandfly, while the immature stages were treated by offering larval diet contaminated by Bti in different concentrations diluted by distilled water. Bti could induce mortality to half of the larval and pupal population at 0.26 x 10-5 g/L. The median lethal doses of adults, which were fed on contaminated surgery diet with serial dilutions of Bti, were 1.3 x 10-2 g/L with fructose and 3 x 10-2 g/L with glucose after 47 and 72 hours. The longevity period of larvae and pupae fed on contaminated larval diet showed negative correlation with bacterial concentrations, except for high concentrations. The bacterial control of the sandfly Ph. Papatasi could be recommended, particularly as adulticide agents