High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination

• Published in: Malaria Journal
• Main Authors: Jaishree Raman, Laura Gast, Ryleen Balawanth, Sofonias Tessema, Basil Brooke, Rajendra Maharaj, Givemore Munhenga, Power Tshikae, Vishan Lakan, Tshiama Mwamba, Hazel Makowa, Lindi Sangweni, Moses Mkhabela, Nompumelelo Zondo, Ernest Mohulatsi, Zuziwe Nyawo, Sifiso Ngxongo, Sipho Msimang, Nicole Dagata, Bryan Greenhouse, Lyn-Marie Birkholtz, George Shirreff, Rebecca Graffy, Bheki Qwabe, Devanand Moonasar
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2020
• Subjects: Malaria; South Africa; KwaZulu-Natal; Residual transmission; Asymptomatic carriage; Elimination; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-020-03227-3; https://doaj.org/article/4c75bfc9033545d7bc8259185d13f1e8

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 ...