Insecticide susceptibility analysis of Anopheles gambiae complex in Vlakbult, Mpumalanga 2012/13

Abstract

South Africa is one of the 34 malaria endemic countries that are currently targeting malaria elimination. Although South Africa is also listed as malaria endemic, malaria in South Africa is limited to the North-eastern three provinces of KwaZulu-Natal (KZN), Mpumalanga and Limpopo. Anopheles arabiensis is the major malaria transmitting vector and the causative agent in over 90% of the malaria infections in South Africa had been and remains Plasmodiumfalciparum. Many species of malaria vectors are known to belong to a 'species complex' and therefore look identical morphologically. Such species need to be identified further through the use of modern molecular methods such as Polymerase Chain Reaction (PCR). One such group is the An. gambiae complex, which comprises of eight members: An. gambiae, An. coluzzii and An. arabiensis (major malaria vectors), An. merus, An. melas and An .bwambae (minor or localized vectors) and An. quadriannulatus and An. amharicus are not known to transmit malaria. This study focused on a new vector breeding site identified in Mpumalanga (Vlakbult) m 2011. The aims of this study were to: Obtain data on malaria vector prevalence in Vlakbult, Mpumalanga province (November 2012-January 2013), determine insecticide susceptibility status of An. arabiensis from Vlakbult and to determine sporozoite infectivity rate in wild caught An.arabiensis mosquitoes collected in Vlakbult from November 2012 -January 2013. The study found that the breeding site in Vlakbult had An. arabiensis that were found in this breeding site are susceptible to 4% DDT and 0.05% deltamethrin and that the wild caught Anopheles arabiensis found in this area (Vlakbult) were not infected with P. falciparum parasites. For the Mpumalanga malaria control program, these findings mean that there is a need for continuing entomological and vector susceptibility surveillance in order to inform malaria control and elimination efforts. Mpumalanga malaria control also needs to review their vector control activities in Vlakbult to ensure that the presence of An. arabiensis is addressed appropriately since the presence of the malaria transmitting vector in Vlakbult poses a potential risk for an outbreak of malaria.