Seasonal variations in Anopheles species (Diptera: Culicidae) and malaria incidence in Kodok locality, Upper Nile State, Republic of South Sudan
Keywords:
kodok locality, upper nile state, republic of south sudan, An. gambiae s.s, An. arabiensis, Anopheles density, seasonal change, malariaAbstract
Malaria transmission in sub-Saharan Africa (SSA) is dominated by 3 widespread vectors: Anopheles gambiae s.s. Giles, An. arabiensis Patton, and An. funestus Giles (Diptera: Culicidae). Malaria is caused by the parasite Plasmodium, transmitted by the bite of an infected female Anopheles. A Cross- sectional study was conducted from April 2020 to March 2021 in Kodok locality (KL), Upper Nile State (UNS), Republic of South Sudan (RSS), to determine the larval and indoor resting density of adults, their seasonal changes, and relate them to the number of malaria cases in each KL area (hai), these are: Bilpam, Ochugi, Nevasha and Salam. These areas are surrounded with swamps and man-made ponds. The number of Anopheles and other mosquito adults in a given room was determined by using pyrethrum spray sheet (PSS) collection and the dipping method was used for larval collection from swamps and waste-water. The collected adults were identified as follows: An. gambiae s.s. (67 %), An. arabiensis (27.1%) and other mosquitoes (An. funestus, Culex and Aedes; 5.9%). The density/HH was determined, in the rainy-season (April-Oct.) and the dry- season (Nov. to March). An. gambiae larvae formed 85.4 % and other mosquitoes formed 14.6%. Malaria cases registered within 12 months in KL were 1,956, ranging from 96 to 271 case/month. The highest was during April and the lowest was that of August. It is concluded that 3 Anopheles species are present in the study area. An. gambiae is the dominant species during both seasons. All detected species densities and malaria cases were higher in the wet- season than the dry-season. This information must be seriously considered during the vector control programs.
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