Decadal epidemiology of malaria in KwaZulu‑Natal, a province in South Africa targeting elimination

BACKGROUND : Although malaria remains a noteworthy disease in South Africa, the provinces are at differing stages of the malaria elimination continuum. KwaZulu-Natal has consistently reported the lowest number of cases over the past 5 years and it is expected that the goal of elimination will be achieved in this province over the next few years. The study reports on few key indicators that realistically represents the provinces progress over the past decade. Local and imported morbidity and mortality is seen as the key indicator as is malaria in children under the age of five and pregnant women. The only vector control intervention in the province is indoor residual spraying (IRS) and this gives an estimate of the population protected by this intervention. METHODS : Trend analysis was used to examine the changing epidemiology in KwaZulu-Natal over the past decade from 2008 to 2018. The data used in this decadal analysis was obtained from the provincial Department of Health. Since malaria is a medically notifiable disease, all malaria cases diagnosed in the province are reported from health facilities and are captured in the malaria information system in the province. RESULTS : The results have shown that imported cases are on the increase whilst local cases are decreasing, in keeping with an elimination objective. Preventing secondary cases is the key to reaching elimination. Only 10% of the cases reported occur in children under 5 years whereas the cases in pregnant women account for about 1% of the reported cases. Over 85% of the houses receive IRS and this is also the same proportion of the population protected by the intervention. CONCLUSION : Several challenges to elimination have been identified but these are not insurmountable. Although there are major impediments to achieving elimination, the changing epidemiology suggests that major strides have been made in the past 10 years and KwaZulu-Natal is on track to achieving this milestone in the next few years.A South African Medical Research Council Intramural Research Awardhttp://www.malariajournal.comam2020School of Health Systems and Public Health (SHSPH

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

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 communitybased malaria prevalence survey. All consenting participants were tested for malaria by both conventional and highlysensitive 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.Additional file 1: Table S1. Additional risk factors associated with Plasmodium falciparum malaria from the community-based KAP survey by study municipality in uMkhanyakude district, KwaZulu-Natal.The authors wish to the thank all the study participants for their willingness to participant in the survey, the entire KZN malaria programme for all their support prior, during and after the survey, the Bill and Melinda Gates Foundation (BMGFMELIM1), the Global Fund to Fight AIDS, Tuberculosis and Malaria (QPA-M-LSDI), the Clinton Health Access Initiative, the South African Medical Research Council, the South African National Institute for Communicable Diseases and the Universities of California-San Francisco, Pretoria and Witwatersrand for financial and/or logistic support and Prof John Frean for critically reviewing the draft manuscript.JR conceived the study and designed the study and analysis with LG, RB, BB, RM, GM, PT, VL, SM, RG, GS, ND, BQ and DM. BB, RM, GM, PT, ZN and SN led the entomological field and laboratory investigations. JR, LG, RB, LS, MM, NZ and EM oversaw the administration of the KAP and prevalence survey, collection and shipment of field samples. TM and JR optimized and conducted certain parasite molecular assays while ST, BG, HM and LB optimized and conducted the parasite relatedness assays. JR and LG conducted the statistical analysis, while LG generated the spatial maps. JR drafted the manuscript and all authors reviewed the manuscript critically for critical intellectual content.A Bill and Melinda Grant; a Clinton Health Access Initiative grant, NICD research funding; Wits Research Institute for Malaria; a Global Fund Grant; South African Medical Research Council research funding; the South African Research Chairs Initiative of the Department of Science and Technology, administered through the South African National Research Foundation.https://malariajournal.biomedcentral.com/am2020BiochemistryGeneticsMicrobiology and Plant Patholog