Malaria risk and receptivity: Continuing development of insecticide resistance in the major malaria vector Anopheles arabiensis in northern KwaZulu-Natal, South Africa

Givemore Munhenga; Shüné V. Oliver; Leanne N. Lobb; Theresa T. Mazarire; Windy Sekgele; Thabo Mashatola; Nondumiso Mabaso; Dumsani M. Dlamini; Malibongwe Zulu; Fortunate Moletsane; Blaženka D. Letinić; Jacek Zawada; Ashley Burke; Yael Dahan-Moss; Avhatakali Matamba; Maria Kaiser; Basil D. Brooke

doi:10.17159/sajs.2022/11755

Authors

Givemore Munhenga 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa https://orcid.org/0000-0002-8431-6947
Shüné V. Oliver 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa https://orcid.org/0000-0003-0658-6658
Leanne N. Lobb 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Theresa T. Mazarire 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Windy Sekgele Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Thabo Mashatola 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Nondumiso Mabaso Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Dumsani M. Dlamini Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Malibongwe Zulu Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Fortunate Moletsane Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Blaženka D. Letinić 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Jacek Zawada 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Ashley Burke 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Yael Dahan-Moss 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Avhatakali Matamba Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
Maria Kaiser 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
Basil D. Brooke 1.Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; 2.Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa https://orcid.org/0000-0002-8857-1304

DOI:

https://doi.org/10.17159/sajs.2022/11755

Keywords:

malaria, vector control, risk and receptivity, malaria elimination

Abstract

Malaria incidence in South Africa is highest in the three endemic provinces: KwaZulu-Natal, Mpumalanga and Limpopo. The contribution to malaria transmission by several mosquito species, variation in their resting behaviours and low levels of insecticide resistance makes it necessary to periodically monitor Anopheles species assemblages and resistance phenotypes in vector populations. The aim of this study was therefore to assess Anopheles species assemblage in northern KwaZulu-Natal and to collect insecticide susceptibility data for An. arabiensis, the primary vector of malaria in that province. Anopheles specimens were collected from Mamfene, Jozini, northern KwaZulu-Natal from November 2019 to April 2021. Progeny of wild-collected An. arabiensis females were used for standard insecticide susceptibility tests and synergist bioassays. Anopheles arabiensis contributed 85.6% (n=11 062) of the total catches. Samples for subsequent insecticide susceptibility bioassays were selected from 212 An. arabiensis families. These showed low-level resistance to DDT, permethrin, deltamethrin, and bendiocarb, as well as full susceptibility to pirimiphos-methyl. Synergist bioassays using piperonyl butoxide and triphenyl phosphate suggest oxygenase-based pyrethroid and esterase-mediated sequestration of bendiocarb. These low levels of resistance are unlikely to be operationally significant at present. It is concluded that northern KwaZulu-Natal Province remains receptive to malaria transmission despite ongoing control and elimination interventions. This is due to the perennial presence of the major vector An. arabiensis and other secondary vector species. The continued detection of low-frequency insecticide resistance phenotypes in An. arabiensis is cause for concern and requires periodic monitoring for changes in resistance frequency and intensity.

Significance:

Insecticide resistance in the major malaria vector Anophelesarabiensis in northern KwaZulu-Natal Province is cause for concern in terms of resistance management and ongoing vector control leading toward malaria elimination.
Despite ongoing control interventions, northern KwaZulu-Natal remains receptive to malaria owing to the perennial presence of several Anophelesvector species.