Insecticide resistance in the malaria vector Anopheles arabiensis in Mamfene, KwaZulu-Natal

Abstract

The control of malaria vector mosquitoes in South Africa’s affected provinces is primarily based on indoor spraying of long-lasting residual insecticides. The primary vectors in South Africa are Anopheles arabiensis and An. funestus. South Africa’s National Malaria Control Programme has adopted a malaria elimination agenda and has scaled up vector control activities accordingly. However, despite these plans, local transmission continues and is most likely because of outdoor feeding by populations of An. arabiensis. An outdoor Anopheles surveillance system has been set up in three sections of the Mamfene district in northern KwaZulu- Natal in order to assess the extent of outdoor resting An. arabiensis in Mamfene and to assess the current insecticide susceptibility status of this population. According to WHO criteria, the An. arabiensis samples tested showed evidence of resistance to deltamethrin (pyrethroid), DDT (organochlorine) and bendiocarb (carbamate), and full susceptibility to the organophosphates pirimiphos-methyl and fenitrothion. Pre-exposure to piperonyl butoxide completely nullified the deltamethrin resistance otherwise evident in these samples, supporting previous studies implicating monooxygenase-based detoxification as the primary mechanism of pyrethroid resistance. The data presented here affirm the presence of pyrethroid and DDT resistance previously detected in this population and also indicate the comparatively recent emergence of resistance to the carbamate insecticide bendiocarb. These data show that special attention and commitment needs to be given to the principles of insecticide resistance management as well as to investigations into alternative control techniques designed to target outdoor-resting An. arabiensis in northern KwaZulu-Natal.

Temporal and spatial trends in insecticide resistance in Anopheles arabiensis in Sudan: outcomes from an evaluation of implications of insecticide resistance for malaria vector control

“…gambiae ( s.l . ), from Cote d’Ivoire [ 44 ], Benin [ 45 ], Burkina Faso [ 46 , 47 ], Mali [ 48 ] and South Africa [ 49 ]. Anopheles arabiensis populations from all sentinel sites exhibited high levels of resistance to deltamethrin and DDT.…”

Mosquito community composition in South Africa and some neighboring countries

“…Lettering in the first column corresponds to the letter in the map insert in Fig. 1 Locality Latitude, Longitude Survey period N TT ± SD a N LT ± SD a Net vs light trap P -value b % vectors c CCM d CCM av d CCM NT d CCM LT d H Mozambique A Vilankulo 21°57.1'S, 35°18.8'E 21–28 January 784 ± 662 na na 93.7 2353 (13) [ 5 ] 2205 (5) [ 3 ] 2353 (13) [ 5 ] na 0.89 Botswana B Moremi Game Reserve 19°07.1'S, 23°23.2'E 20–23 February 115 ± 93 163 ± 130 < 0.001 76.2 1339 (27) [ 8 ] 1020 (7) [ 4 ] 689 (15) [ 6 ] 650 (25) [ 8 ] 1.74 C Khwai Community Conservancy Area 19°07.3'S, 23°52.1'E 20–23 February 186 ± 128 399 ± 336 < 0.001 64.2 1356 (18) [ 8 ] 870 (4) [ 3 ] 559 (12) [ 4 ] 797 (16) [ 8 ] 1.79 Kruger National Park, South Africa D Shingwedzi 23°06.7'S, 31°27.4'E 18–21 March 17 ± 9 33 ± 10 …”

“…Historic interest in the mosquitoes of southern Africa has largely been based on their role as vectors of human or animal disease. Malaria-associated morbidity and mortality was very high during the early decades of the 20th century [ 1 – 5 ] and gave rise to a disproportionately large body of still-increasing literature on anopheline mosquitoes [ 6 – 13 ]. Outbreaks of arboviral disease, associated with high mortality in livestock, resulted in sustained research on non-anopheline mosquitoes [ 14 – 22 ], with an associated surge in publications relating to regional surveys commencing in the 1950’s and 1960’s for arboviruses affecting humans [ 23 – 29 ].…”

Characterising the effect of Akirin knockdown on Anopheles arabiensis (Diptera: Culicidae) reproduction and survival, using RNA-mediated interference

“…This problem is compounded by the fact that insecticide resistance is increasing in the vector population, which is most likely due to increased selection pressure [7]. In South Africa, the An.…”

“…In South Africa, the An. arabiensis population has shown resistance to DDT (Dichlorodiphenyltrichloroethane), pyrethroids, and carbamates, especially in northern KwaZulu-Natal [7][8][9]. This places tremendous pressure on the goal of eliminating malaria from South Africa by 2030 [2], and necessitates the need for the development of additional vector control interventions.…”