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University of Liverpool (2003)

Ecology and population structure of Anopheles arabiensis in Sudan

Aboud, Mariam Atta El Mannan

Titre : Ecology and population structure of Anopheles arabiensis in Sudan

Auteur : Aboud, Mariam Atta El Mannan.

Université de soutenance  : University of Liverpool

Grade : Doctor of Philosophy (PhD) 2003

Anopheles arabiensis is the major malaria vector in Sudan, including Khartoum State where malaria has increased in recent years. The present study has been an attempt to address the biology of An. arabiensis in the dry zone of Khartoum State and determine whether there are differences in ecology and biology of the populations in arid and irrigated areas and if these differences are reflected in their population structure. A study of the ecology and bionomics of Anopheles arabiensis was conducted from November 1988 to October 1999 in irrigated areas adjoining the Nile and arid-zone villages some 25 km from the Nile. Additional samples were collected in July-August 2000 and August 2001. The results indicated a marked seasonal variation in vector density in both dry and irrigated areas during the year, reflecting the annual pattern of rainfall. Even in irrigated areas, vector densities were low during the long dry season. The adult population density is assumed to be extremely low in arid villages during the dry season since, despite extensive searches, no adult mosquitoes were found. In one dry zone village (El Mowailih), continuous breeding of An. arabiensis was seen throughout the dry season in water leaking from water storage tanks. This suggest that females may rest cryptically in inaccessible sites, such as wells, during the dry season. During the short rainy season, a relatively high density of An. arabiensis mosquitoes was observed in the arid areas : 3.3 bites/man/night and 39.2/room compared with 5.2 bites/man/night and 7.3/room in the irrigated area. The populations of arid areas appear to be more endophilic than those in irrigated areas. The human blood index was 82.2% (n=500). The sporozoite rates were estimated to be 1.2 and 1.6% in irrigated and dry areas respectively and the corresponding entomological inoculation rates were 6.2 and 5.3 positive bites/person/season.

Présentation : EThOS (UK)

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