Sandflies (Diptera: Psychodidae) in a focus of visceral leishmaniasis in White Nile, Sudan

Abstract

Visceral leishmaniasis (VL) has been known to occur since the 1980s on the western bank of the White Nile River (Central Sudan), 150 km south of Khartoum, and has resulted in high mortality. The most recent outbreak of the disease in this area began in 2006. Entomological surveys were carried out during May 2008, June 2010 and May and July 2011 in the White Nile area. Sandflies were collected using Centers for Disease Control light traps and sticky oil traps in the village of Kadaba and the nearby woodland. Phlebotomus females were dissected for the presence of Leishmania promastigotes. A total of 17,387 sandflies, including six species of Phlebotomus and 10 species of Sergentomyia, were identified. The Phlebotomus species recorded were Phlebotomus orientalis, Phlebotomus papatasi, Phlebotomus bergeroti, Phlebotomus duboscqi, Phlebotomus rodhaini and Phlebotomus saevus. P. orientalis was collected in both habitats. The relative abundance of P. orientalis in the woodland habitat was higher than that recorded in the village habitat. In the woodland habitat, there was a notable increase in the relative abundance of P. orientalis during the surveys conducted in 2008 and 2010 compared to 2011. None of the 311 P. orientalis females dissected were infected with Leishmania promastigotes, although relatively high parous rates were recorded in both habitats. Based on the distribution of P. orientalis recorded in this study, this species is the most likely vector of VL in the endemic focus in the White Nile area. Further investigation is required to elucidate the seasonal abundance and distribution of the vector, as well as the transmission season of VL in both habitats so that appropriate control strategies for the vector can be designed.

Habitat preference and seasonal dynamics of Phlebotomus orientalis in urban and semi-urban areas of kala-azar endemic district of Kafta Humera, northwest Ethiopia

“…bergeroti and P. duboscqi) occurring in the same geographical region of northwest Ethiopia is significant that in no other place in Ethiopia have they ever been found together in the same geographical region but they are sympatric in the neighbouring Sudan (Widaa et al, 2012) and northern Ethiopia (Tahitay Adiabo district) (Gebresilassie et al, 2015b). While P.…”

Population dynamics and habitat preferences of Phlebotomus orientalis in extra-domestic habitats of Kafta Humera lowlands – kala azar endemic areas in Northwest Ethiopia

“…Phlebotomus martini and Phlebotomus orientalis are the two principal vectors of kala-azar in East Africa [3, 4]. Phlebotomus martini is associated with Macrotermes termite mounds in southern Ethiopia [5] while P. orientalis is associated with Acacia seyal - Balanites aegyptiaca forest and deeply cracking soil in eastern Sudan and northwestern Ethiopia [6–18]. P.orientalis is believed to depend on the black cracking soil as day resting and breeding site in dry season [7, 8].…”

A Comparative Assessment of Visceral Leishmaniasis Burden in Two Eco-epidemiologically Different Countries, India and Sudan

“…Model parameter estimates, and their ranges, and distributions were obtained for India and Sudan using prevalence data, published literature, and methodology developed in sections below [22,27,51,77,86]. In the case of the species of Phlebotomus sandflies , most of the parameter estimates were taken from data collected via field studies in parasitology and ecology literature [22, 27, 51].…”

“…In Sudan, Phlebotomus Orientalis is the dominant sandfly vector associated with anthroponotic L. donovani transmission. [28, 31, 38, 39, 72, 86]. Typically, P. Orientalis is considered a forest species and its abundance is frequently associated with the presence of the savanna woodland tree species Acacia Seyal and Balanites aegyptiaca and deeply cracked vertisols (black cotton soil) [28, 29].…”