Browsing by Author "Kigadye, E. S. P."

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    Diversity, Spatial and Temporal Abundance of Anopheles Gambiae Complex in the Rufiji River Basin, South-Eastern Tanzania
    (2010) Nkwengulila, Gamba; Magesa, S. M.; Abdulla, Salim; Kigadye, E. S. P.
    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.
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    Investigations on Risk Factors for Malaria in Rufiji District, Tanzania
    (2013) Kigadye, E. S. P.; Nkwengulila, Gamba; Magesa, S.; Abdulla, Salim
    Rufiji District is an area with endemic and perennial malaria. The aim ofthis study was to assess the factors contributing to increased malaria risk in thestudy area. The factors investigated included; mode of house construction,protection against mosquito bites and human behaviour. Parameters recorded forevaluating the mode of house construction were; type of wall, roofing materials,presence of open eaves between wall and roof and the type of window. Structuredquestionnaires were used to assess household mosquito avoidance behaviour andutilization of bed nets. Medium scale behavioural surveys were carried out todetermine time spent by individuals outdoors during the night. This was then plottedagainst mean hourly mosquito catches. Generally, house constructed using mud,grass, palm walls, and roofs made of grass/palm thatch, houses with no or openwindows and without mosquito gauze and houses with open eaves and lowutilization of bed nets (treated and untreated) were common over the entire studyarea. Of the 2,423 houses walls examined; 90% were constructed using mud, 61%were roofed using grass, 98% had eaves between wall and roof, and 49% had nowindows while 45% of windows had no mosquito gauzes. There were highlysignificant differences (p < 0.001) within all the above variables investigated. Only21% of the households used bed nets of which only 7.5% were insecticides treated.There were highly significant differences (p < 0.0001) within variables investigatedon mosquito avoidance behaviour. Most individuals, both children and adults,remained outdoors up to 22.00 hrs. Environmental factors, poorly constructedhouses, low rate of utilization of bed nets and other protective measures, andpoverty were identified as risk determinants for malaria in the study area.Intervention measures relevant to the study area are discussed.
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    The Occurrence of Digenean Larvae in Freshwater Snails at Mbezi-Temboni Pond, Dar Es Salaam
    (2001) Kigadye, E. S. P.; Nkwengulila, Gamba
    The abundance of digenean larvae in snails at a pond in Mbezi-Temboni, Dar es Salaam, was investigated from July 1996 to June 1997. A total of 2,112 snails belonging to three species, Bulinus globosus Morelet 1866, Bulinus forskalii Ehrenberg 1869, and Melanoides tuberculata Müller 1774 were examined, and 28 (1.3%) were found infected by four species of digenean trematodes. Trematodes were recovered only from Bulinus species; none of the examined M. tuberculata was infected. B. globosus was infected by Schistosoma haematobium Bilharz 1852 (1.14%), unidentified furcocercous cercariae (0.4%), and echinostome cercariae (0.76%). B. forskalii was infected by echinostome cercariae (0.25%) only, Generally, prevalence of digenean larvae in their host snails was very low and varied with the seasons. Variation of prevalence with the seasons was probably influenced by factors such as rainfall, population dynamics of host, and temporal availability of definitive hosts. Furthermore, S. haematobium and echinostome cercariae from B. globosus occurred alternately but not concurrently, suggesting a possible presence of intramolluscan competition.
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    Occurrence of Digenean Larvae in Freshwater Snails in the Ruvu Basin, Tanzania
    (2009) Nkwengulila, Gamba; Kigadye, E. S. P.
    A survey was carried out on digenean larvae infecting freshwater snails in five habitats in Dar es Salaam, Ruvu and Morogoro. 9424 snails belonging to 12 species from five families were examined for digenean infection from July 1996 – June 1997. 20 morphologically distinguishable cercariae were recovered. Multiple infections were not recorded. While the general prevalence of digeneans in snails was low (3.5%), variations occurred between seasons, among habitats and snail host species. Prevalence was high during the dry season but low in the rain season. Among habitats, highest prevalence was recorded at Kinondoni pond and lowest at Ruvu ponds, and was highest in Lymnaea natalensis followed by Bulinus tropicus but was lowest in Bulinus nasutus.