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.

BackgroundAlthough 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.MethodsTrend 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.ResultsThe 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.ConclusionSeveral 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.

This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0. A high-level review was conducted of the literature pertaining to the challenges and opportunities for eliminating malaria on the African continent. Although malaria mortality and morbidity are on the decline, the disease remains one of public health importance. Africa has invariably borne the brunt of the disease, recording the highest number of cases and deaths. However, with greater emphasis being placed on the disease by the international community, partnerships have developed to boost malaria elimination efforts on the continent. One such initiative is the Roll Back Malaria (RBM) partnership which aims to facilitate malaria elimination through increasing resources and awareness. Many cross-border initiatives have been established which treat malaria as a regional problem rather than a country-specific one. Accelerated malaria control efforts have led to a 37% decrease in cases and 60% reduction in deaths. Multi-country efforts have resulted in marked reductions of transmission in the region. Although there have been noteworthy gains in curtailing the disease, new challenges have arisen. The main among these are residual malaria and outdoor biting. One of the main drivers of residual malaria is insecticide resistance. Adding to the burden of residual transmission is the discovery of new vectors that may exist at low densities. To exacerbate these issues is the challenge of malaria imported from high-to low-transmission areas. Nevertheless, compared with the historical picture, we are winning the battle against malaria. Countries in Africa are being certified malaria-free. Partnerships have been developed to take forward the RBM Global Malaria Action Plan. Elimination agendas can only be successful if funding remains sustainable, with greater reliance on domestic funding.

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 investigation. Conclusion If KwaZulu-Natal is to successfully halt local malaria transmission and prevent the re-introduction of malaria, greater efforts needs 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.

Background: Although great strides have been made in controlling malaria, the disease is of significant public health importance. Historically, efforts to control the vector has concentrated on adult vector control targeting the female Anopheles mosquitoes. As there is now a focus on eliminating residual malaria from KwaZulu-Natal, new strategies are being investigated to increase the impact of malaria elimination strategies. Greater attention is now being given to larval control, as a complementary measure to indoor residual spraying. However, there is a large gap in knowledge of the bionomics of the larval stages of this mosquito vector of malaria in South Africa. In order to focus on both larval and adult mosquito control methods, larval development and the reproductive stages of the vector were investigated since these variables influences our ability to impact mosquito populations through larval control. This study was therefore conducted to determine the peak eruption times and the emergent sex ratios, as well as the peak egg oviposition time in order to attack the mosquito when it is at its most vulnerable and when control interventions will have the most impact.Results: Oviposition studies showed two peaks corresponding with late evening and again just before dawn. Most eggs were also laid in the first half of the night (18h00 – midnight). Most mosquitoes erupted just after sunset and the sex ratios showed that twice as many females as males emerged. Females readily took a bloodmeal after oviposition or just after erupting. Hatch rate to viable first instar larvae was 74.5%.Conclusions: The results of this study have provided information as to when interventions would be most effective in controlling mosquito populations and have provided information that highlights the value of larval control as a complementary measure to adult mosquito control. The most vulnerable stages of the female Anopheles arabiensis are when they have just emerged or when they have just oviposited. Vector control strategies should be designed to target these vulnerable stages at the breeding sites in order to have maximum impact.

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

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

Background Although great strides have been made in controlling malaria, the disease is of significant public health importance. Historically, efforts to control the vector has concentrated on adult vector control targeting the female Anopheles mosquitoes. As there is now a focus on eliminating residual malaria from KwaZulu-Natal, new strategies are being investigated to increase the impact of malaria elimination strategies. Greater attention is now being given to larval control, as a complementary measure to indoor residual spraying. However, there is a large gap in knowledge of the bionomics of the larval stages of this mosquito vector of malaria in South Africa. In order to focus on both larval and adult mosquito control methods, larval development and the reproductive stages of the vector were investigated since these variables influences our ability to impact mosquito populations through larval control. This study was therefore conducted to determine the peak eruption times and the emergent sex ratios, as well as the peak egg oviposition time in order to attack the mosquito when it is at its most vulnerable and when control interventions will have the most impact. Results Oviposition studies showed two peaks corresponding with late evening and again just before dawn. Most eggs were also laid in the first half of the night (18h00 – midnight). Most mosquitoes erupted just after sunset and the sex ratios showed that twice as many females as males emerged. Females readily took a bloodmeal after oviposition or just after erupting. Hatch rate to viable first instar larvae was 74.5%. Conclusions The results of this study have provided information as to when interventions would be most effective in controlling mosquito populations and have provided information that highlights the value of larval control as a complementary measure to adult mosquito control. The most vulnerable stages of the female Anopheles arabiensis are when they have just emerged or when they have just oviposited. Vector control strategies should be designed to target these vulnerable stages at the breeding sites in order to have maximum impact.