Host-biting rate and susceptibility of some suspected vectors to Leishmania braziliensis

Abstract

BackgroundAmerican tegumentary leishmaniasis is a serious Brazilian public health problem. This diseases is attributed to seven species of Leishmania, however, the majority of cases are associated with Leishmania braziliensis. Some phlebotomine species have been implicated in the transmission of this parasite, nonetheless only Psychodopygus wellcomei has had its vectorial competence demonstrated. Thus this study sought to assess some parameters related to the vectorial capacity of anthropophilic species of sand fly occurring in São Paulo state: Pintomyia fischeri, Migonemyia migonei Nyssomyia intermedia, Nyssomyia whitmani, Expapillata firmatoi and Psychodopygus ayrozai, under laboratory conditions. These parameters were the duration of the gonotrophic cycle, proportion of females which feed on hamster, the rate of infection by L. braziliensis and the duration of the extrinsic incubation period.MethodsThe sandflies were collected in three regions of the São Paulo state: Greater São Paulo and the Mogi Guaçu and Iporanga municipalities. To assess the proportion of engorged females the insects were fed on hamsters to estimate the duration of the gonotrophic cycle. To estimate the susceptibility to infection of each species, their females were fed on hamsters infected with Leishmania braziliensis and dissected to ascertain the localization of the flagellates and estimate the extrinsic incubation period.ResultsLow hamster attractiveness to Ps. ayrozai was observed. A high proportion of engorged females was observed when the hamster had its whole body exposed. The gonotrophic cycle ranged between three and eight days. Mg. migonei, Pi. fischeri, Ny. neivai, Ny. intermedia, Ny. whitmani and Ex.firmatoi presented susceptibility to infection by L. braziliensis. The highest infection rate (34.4%) was observed for Ny. whitmani and the lowest for Ny. intermedia (6.6%). Mg. migonei presented late-stage infection forms on the fifth day after feeding, but in the other species these forms were observed as from the fourth day.ConclusionsOur results, together with other parameters of their behavior under natural conditions, suggest the potential role of Ex. firmatoi as vector of this parasite and reinforce that of Mg. migonei, Pi. fischeri, Ny. neivai, Ny. intermedia and Ny. whitmani in the areas in which they occur.

Occurrences of Phlebotomine Sand Flies (Diptera: Psychodidae) Potentially Associated with Leishmaniasis Transmission in Urban Parks in the City of São Paulo, Brazil

“…fischeri, Mg. migonei, and Ny. whitmani) are anthropophilic and have been reported in areas where cases of leishmaniasis occur and may be involved in the transmission of Leishmania braziliensis (Viannia 1911), the causative agent of tegumentary leishmaniasis (Diniz et al 2014). Pintomyia fischeri was one of the most abundant species (41.62%) found in all 5 parks.…”

“…Pintomyia fischeri was one of the most abundant species (41.62%) found in all 5 parks. In addition to its possible role in the transmission of L. (V.) braziliensis, this species is susceptible to infection by, and is a potential vector of, Leishmania infantum (Nicolle 1908), the etiologic agent of visceral leishmaniasis (Diniz et al 2014, Galvis-Ovallos et al 2017. Migonemyia migonei was found in very low abundance, but it is a species of epidemiological importance, which has been recently defined by Guimarães et al (2016) In addition to being considered a vector of L. (V.) braziliensis in various regions of Brazil, the 3rd epidemiologically important species, Ny.…”

Aspectos ecológicos de flebotomíneos (Diptera: Psychodidae) no Parque Estadual do Jaraguá na cidade de São Paulo, Estado de São Paulo, Brasil

“…al., 2013). Além disto, estas espécies infectaram-se experimentalmente por Leishmania braziliensis e sobreviveram ao período de incubação extrínseco (Diniz et. al., 2014 (Iversson et.…”

“…fischeri e Ps. ayrozai, que têm sido incriminadas ou suspeitas de atuarem como vetoras de Leishmania spp., agentes de LTA(Diniz et al 2014). Destaca-se o encontro novamente de uma fêmea provável de mais baixos, e os mais altos, no verão.…”

Investigação e documentação de flagelados no tubo digestório de flebotomíneos

“…A descrição e documentação do processo de obtenção de fêmeas em campo, procedimentos para garantir a sobrevivência delas até a dissecção para investigação da infecção por flagelados e o processo de dissecção foram feitos com base em atividades desenvolvidas no LESP/ Flebotomíneos, quando do desenvolvimento de estudos ecológicos de flebotomíneos e aspectos da capacidade vetorial para Leishmania (BRILHANTE et al, 2017;GALVIS 2011;DINIZ et al, 2014;GALVIS et al, 2017;MOSCHIN et al, 2013).…”