Diversity, spatial and temporal abundance of Anopheles gambiae complex in the Rufiji River basin, south-eastern Tanzania

Abstract

Abstract:The Anopheles gambiae complex contains the most efficient malaria vectors in the world. Identification of the species and the concomitant distribution are vital for effective malaria control. The objective of the study was to establish the diversity, spatial and seasonal abundance of malaria vectors in the Rufiji River Basin in Tanzania and the implications on malaria vector control. Mosquitoes were collected using CDC light-traps. Anopheles mosquitoes were identified by conventional keys. Anopheles gambiae complex were speciated using standard PCR method. Of the 562 specimens analysed by PCR 69% produced fragments equivalent to An. gambiae s.s. (390 bp), 23% equivalent to An. arabiensis (315bp), and 7% as An. merus (464 bp). An. gambiae s.s. and An. merus were more abundant on the plateau than on the flood plain (Fisher's exact test, P< 0001), whereas An. arabiensis was equally abundant between the two sites (Fisher's exact test, P=1656). The density of the three sibling species of An. gambiae complex also varied with the seasons. An. gambiae s.s. and An. arabiensis were most predominant species during the start of the rainy season, but as season progresses, An. gambiae s.s. predominated. An. merus was only recorded during the short rainy season. In conclusion, both An. gambiae s.s., An. arabiensis and An.merus are malaria vectors in the Rufiji River basin and that An. merus is recorded for the first time in the south-eastern coast of Tanzania. These findings are important in the planning and implementation of malaria vector control activities in the Rufiji River basin, south-eastern Tanzania. ____________________________________________________________________________________

Relationship between child survival and malaria transmission: an analysis of the malaria transmission intensity and mortality burden across Africa (MTIMBA) project data in Rufiji demographic surveillance system, Tanzania

“…The drop in mortality is partly associated with success in interventions and control strategies targeting malaria transmission, such as insecticide-treated nets (ITNs) and efficacious anti-malarial drugs [9-12]. For instance in the Rufiji demographic surveillance system (DSS), changing of the first-line drug for malaria treatment from chloroquine to sulphadoxine-pyrimethamine and increasing coverage of ITNs were followed by a sharp decline in mortality and malaria transmission [13,14]. The traces on the possible relationship between mortality and fluctuation in malaria transmission exists, however, lack of vital registration in developing countries, unreliable information on specific causes of deaths, problems related to disease diagnosis e.g.…”

Major Disease Vectors in Tanzania: Distribution, Control and Challenges

“…arabiensis and An. gambiae s.s. has been observed to occur in different proportions in other regions of mainland Tanzania [19][20][21][22]. An.…”

Malaria entomological profile in Tanzania from 1950 to 2010: a review of mosquito distribution, vectorial capacity and insecticide resistance

“…north, north-east and east. From early 1960s to 1985 all research activities on malaria vectors were almost concentrated in Tanga (Gillies and Wilkes, 1965 ;Balirwa, 1975;Lines et al, 1987;Magesa et al, 1991;Wilkes et al, 1995;Mboera et al, , 2010Temu et al, 1998;Malima, 1999;Braimah et al, 2005;Kulkarni et al, 2006a;Kigadye et al, 2010). Majority of the articles indicated the occurrence of An.…”

“…No article reported on how the M & S molecular forms of the gambiae s.s are distributed in the country. Anopheles merus were reported to dominate the mangrove and coastal part of the country (Bushrod, 1981;Mnzava & Kilama, 1986;Shiff et al, 1995;Temu et al, 1998;Kigadye et al, 2010) (Figure 4). Studies also indicated the presence of An.…”