Biting behaviour and potential vector status of anthropophilic blackflies in a new focus of human onchocerciasis at Minaçu, central Brazil

Abstract

Monthly collections were made of man-biting female blackflies: Simulium auripellitum Enderlein, S. guianense Wise, S. minusculum Lutz and S. nigrimanum Macquart (Diptera: Simuliidae) from four catching stations in the newly discovered focus of human onchocerciasis at Minaçu (13 degrees 35 minutes S 48 degrees 18 minutes W), 300 km north of Brasília in Goiás State. These provided baseline data on biting habits, population density and seasonal prevalence during the year before completion of the Serra da Mesa hydroelectric dam on the Rio Tocantins near Minaçu, in a project investigating the effect of dam construction on onchocerciasis transmission in the area. All four simuliid species were most abundant during the dry season, and only bit in low numbers (S. auripellitum S. minusculum, S. nigrimanum) or were absent (S. guianense) in the wet season. Simulium minusculum was the predominant species at all catching stations, being particularly abundant by the large River Tocantins. The other three species were mainly associated with smaller rivers. In the dry season, biting rhythms of S. minusculum varied with catching site, while S. nigrimanum showed peaks of activity in early morning and during the afternoon. Experimental infection with Onchocerca volvulus (Leuckart) (Nematoda: Onchocercidae), from a human volunteer, showed that this parasite could develop fully in the four simuliid species, which are all considered to be potential vectors in the area.

River-specific macrogenomic diversity in Simulium guianense s. l. (Diptera: Simuliidae), a complex of tropical American vectors associated with human onchocerciasis

“…Shelley et al [47] suggested that cytoform A1 was predominantly zoophilic and, therefore, not a vector in the Minaçu area of Brazil historically afflicted with onchocerciasis. We recorded S .…”

An insight into the sialome of Simulium guianense (DIPTERA:SIMulIIDAE), the main vector of River Blindness Disease in Brazil

“…Indeed, the autogenous S. vittatum has the least expression of salivary secreted proteins and lacks many of the families found in the Neotropical flies. S. nigrimanum was recently suggested as a potential vector of onchocerciasis [136]. …”

The Role of Neotropical Blackflies (Diptera: Simuliidae) as Vectors of the Onchocerciasis: A Short Overview of the Ecology Behind the Disease

“…The major characteristics of the breeding site associated to blackfly larvae distribution and population dynamics are: distance from lake outlets, stream/river size, food supply, substratum, current velocity, depth, light and physico-chemical conditions (Ross & Merrit 1987). There are species adapted to different water current velocities (Palmer & Craig 2000, Roberts & Okafor 1987, Figueiró et al 2008, different river sizes (Shelley et al 2001, Hamada et al 2002, Figueiró et al 2006, etc.…”