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High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination.
Malar J. 2020 Apr 15; 19(1):152.MJ

Abstract

BACKGROUND

KwaZulu-Natal, one of South Africa's three malaria endemic provinces, is nearing malaria elimination, reporting fewer than 100 locally-acquired cases annually since 2010. Despite sustained implementation of essential interventions, including annual indoor residual spraying, prompt case detection using malaria rapid diagnostics tests and treatment with effective artemisinin-based combination therapy, low-level focal transmission persists in the province. This malaria prevalence and entomological survey was therefore undertaken to identify the drivers of this residual transmission.

METHODS

Malaria prevalence as well as malaria knowledge, attitudes and practices among community members and mobile migrant populations within uMkhanyakude district, KwaZulu-Natal were assessed during a community-based malaria prevalence survey. All consenting participants were tested for malaria by both conventional and highly-sensitive falciparum-specific rapid diagnostic tests. Finger-prick filter-paper blood spots were also collected from all participants for downstream parasite genotyping analysis. Entomological investigations were conducted around the surveyed households, with potential breeding sites geolocated and larvae collected for species identification and insecticide susceptibility testing. A random selection of households were assessed for indoor residual spray quality by cone bioassay.

RESULTS

A low malaria prevalence was confirmed in the study area, with only 2% (67/2979) of the participants found to be malaria positive by both conventional and highly-sensitive falciparum-specific rapid diagnostic tests. Malaria prevalence however differed markedly between the border market and community (p < 0001), with the majority of the detected malaria carriers (65/67) identified as asymptomatic Mozambican nationals transiting through the informal border market from Mozambique to economic hubs within South Africa. Genomic analysis of the malaria isolates revealed a high degree of heterozygosity and limited genetic relatedness between the isolates supporting the hypothesis of limited local malaria transmission within the province. New potential vector breeding sites, potential vector populations with reduced insecticide susceptibility and areas with sub-optimal vector intervention coverage were identified during the entomological investigations.

CONCLUSION

If KwaZulu-Natal is to successfully halt local malaria transmission and prevent the re-introduction of malaria, greater efforts need to be placed on detecting and treating malaria carriers at both formal and informal border crossings with transmission blocking anti-malarials, while ensuring optimal coverage of vector control interventions is achieved.

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Authors+Show Affiliations

Raman J
Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa. jaishreer@nicd.ac.za. Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa. jaishreer@nicd.ac.za. UP Institute for Sustainable Malaria Control, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South Africa. jaishreer@nicd.ac.za.
Gast L
Clinton Health Access Initiative, Pretoria, Gauteng, South Africa.
Balawanth R
Clinton Health Access Initiative, Pretoria, Gauteng, South Africa.
Tessema S
Department of Medicine, University of California-San Francisco, San Francisco, USA.
Brooke B
Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa. Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa.
Maharaj R
UP Institute for Sustainable Malaria Control, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South Africa. Office of Malaria Research, South African Medical Research Council, Durban, KwaZulu-Natal, South Africa.
Munhenga G
Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa. Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa.
Tshikae P
Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa.
Lakan V
Office of Malaria Research, South African Medical Research Council, Durban, KwaZulu-Natal, South Africa.
Mwamba T
Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa. Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa.
Makowa H
Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa.
Sangweni L
KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa.
Mkhabela M
KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa.
Zondo N
KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa.
Mohulatsi E
Humana People to People, Jozini, KwaZulu-Natal, South Africa.
Nyawo Z
KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa.
Ngxongo S
KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa.
Msimang S
KwaZulu-Natal Provincial Department of Health, Pietermaritzburg, KwaZulu-Natal, South Africa.
Dagata N
Clinton Health Access Initiative, Pretoria, Gauteng, South Africa.
Greenhouse B
Department of Medicine, University of California-San Francisco, San Francisco, USA.
Birkholtz LM
Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa.
Shirreff G
Clinton Health Access Initiative, Pretoria, Gauteng, South Africa.
Graffy R
Clinton Health Access Initiative, Pretoria, Gauteng, South Africa.
Qwabe B
KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa.
Moonasar D
UP Institute for Sustainable Malaria Control, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South Africa. Malaria Vector Borne and Zoonotic Diseases, National Department of Health, Pretoria, Gauteng, South Africa.

MeSH

Asymptomatic InfectionsCommunicable Diseases, ImportedDisease EradicationEndemic DiseasesHumansMalariaPrevalenceSouth Africa

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32295590

Citation

Raman, Jaishree, et al. "High Levels of Imported Asymptomatic Malaria but Limited Local Transmission in KwaZulu-Natal, a South African Malaria-endemic Province Nearing Malaria Elimination." Malaria Journal, vol. 19, no. 1, 2020, p. 152.
Raman J, Gast L, Balawanth R, et al. High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination. Malar J. 2020;19(1):152.
Raman, J., Gast, L., Balawanth, R., Tessema, S., Brooke, B., Maharaj, R., Munhenga, G., Tshikae, P., Lakan, V., Mwamba, T., Makowa, H., Sangweni, L., Mkhabela, M., Zondo, N., Mohulatsi, E., Nyawo, Z., Ngxongo, S., Msimang, S., Dagata, N., ... Moonasar, D. (2020). High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination. Malaria Journal, 19(1), 152. https://doi.org/10.1186/s12936-020-03227-3
Raman J, et al. High Levels of Imported Asymptomatic Malaria but Limited Local Transmission in KwaZulu-Natal, a South African Malaria-endemic Province Nearing Malaria Elimination. Malar J. 2020 Apr 15;19(1):152. PubMed PMID: 32295590.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination. AU - Raman,Jaishree, AU - Gast,Laura, AU - Balawanth,Ryleen, AU - Tessema,Sofonias, AU - Brooke,Basil, AU - Maharaj,Rajendra, AU - Munhenga,Givemore, AU - Tshikae,Power, AU - Lakan,Vishan, AU - Mwamba,Tshiama, AU - Makowa,Hazel, AU - Sangweni,Lindi, AU - Mkhabela,Moses, AU - Zondo,Nompumelelo, AU - Mohulatsi,Ernest, AU - Nyawo,Zuziwe, AU - Ngxongo,Sifiso, AU - Msimang,Sipho, AU - Dagata,Nicole, AU - Greenhouse,Bryan, AU - Birkholtz,Lyn-Marie, AU - Shirreff,George, AU - Graffy,Rebecca, AU - Qwabe,Bheki, AU - Moonasar,Devanand, Y1 - 2020/04/15/ PY - 2020/02/13/received PY - 2020/04/06/accepted PY - 2020/4/17/entrez PY - 2020/4/17/pubmed PY - 2020/11/18/medline KW - Asymptomatic carriage KW - Elimination KW - KAP KW - KwaZulu-Natal KW - Malaria KW - Malaria importation KW - Rapid diagnostic tests KW - Residual transmission KW - South Africa KW - Vector control SP - 152 EP - 152 JF - Malaria journal JO - Malar J VL - 19 IS - 1 N2 - BACKGROUND: KwaZulu-Natal, one of South Africa's three malaria endemic provinces, is nearing malaria elimination, reporting fewer than 100 locally-acquired cases annually since 2010. Despite sustained implementation of essential interventions, including annual indoor residual spraying, prompt case detection using malaria rapid diagnostics tests and treatment with effective artemisinin-based combination therapy, low-level focal transmission persists in the province. This malaria prevalence and entomological survey was therefore undertaken to identify the drivers of this residual transmission. METHODS: Malaria prevalence as well as malaria knowledge, attitudes and practices among community members and mobile migrant populations within uMkhanyakude district, KwaZulu-Natal were assessed during a community-based malaria prevalence survey. All consenting participants were tested for malaria by both conventional and highly-sensitive falciparum-specific rapid diagnostic tests. Finger-prick filter-paper blood spots were also collected from all participants for downstream parasite genotyping analysis. Entomological investigations were conducted around the surveyed households, with potential breeding sites geolocated and larvae collected for species identification and insecticide susceptibility testing. A random selection of households were assessed for indoor residual spray quality by cone bioassay. RESULTS: A low malaria prevalence was confirmed in the study area, with only 2% (67/2979) of the participants found to be malaria positive by both conventional and highly-sensitive falciparum-specific rapid diagnostic tests. Malaria prevalence however differed markedly between the border market and community (p < 0001), with the majority of the detected malaria carriers (65/67) identified as asymptomatic Mozambican nationals transiting through the informal border market from Mozambique to economic hubs within South Africa. Genomic analysis of the malaria isolates revealed a high degree of heterozygosity and limited genetic relatedness between the isolates supporting the hypothesis of limited local malaria transmission within the province. New potential vector breeding sites, potential vector populations with reduced insecticide susceptibility and areas with sub-optimal vector intervention coverage were identified during the entomological investigations. CONCLUSION: If KwaZulu-Natal is to successfully halt local malaria transmission and prevent the re-introduction of malaria, greater efforts need to be placed on detecting and treating malaria carriers at both formal and informal border crossings with transmission blocking anti-malarials, while ensuring optimal coverage of vector control interventions is achieved. SN - 1475-2875 UR - https://www.unboundmedicine.com/medline/citation/32295590/High_levels_of_imported_asymptomatic_malaria_but_limited_local_transmission_in_KwaZulu_Natal_a_South_African_malaria_endemic_province_nearing_malaria_elimination_ DB - PRIME DP - Unbound Medicine ER -