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

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 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.

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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

10.21203/rs.2.23648/v2 ◽

2020 ◽

Author(s):

jaishree raman ◽

Laura Gast ◽

Ryleen Balawanth ◽

Sofonias Tessema ◽

Basil Brooke ◽

...

Keyword(s):

Malaria Transmission ◽

Malaria Elimination ◽

Diagnostic Tests ◽

Malaria Prevalence ◽

Rapid Diagnostic Tests ◽

Insecticide Susceptibility ◽

Potential Vector ◽

Breeding Sites ◽

Highly Sensitive ◽

Kwazulu Natal

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 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.

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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

10.21203/rs.2.23648/v3 ◽

2020 ◽

Author(s):

Jaishree Raman ◽

Laura Gast ◽

Ryleen Balawanth ◽

Sofonias Tessema ◽

Basil Brooke ◽

...

Keyword(s):

Malaria Transmission ◽

Malaria Elimination ◽

Diagnostic Tests ◽

Malaria Prevalence ◽

Rapid Diagnostic Tests ◽

Insecticide Susceptibility ◽

Potential Vector ◽

Breeding Sites ◽

Highly Sensitive ◽

Kwazulu Natal

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 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.

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Baseline Malaria Prevalence at the Targeted Pre-elimination Districts in Ethiopia

10.21203/rs.3.rs-131535/v1 ◽

2020 ◽

Author(s):

Desalegn Nega ◽

Adugna Abera ◽

Bokretsion Gidey ◽

Sindew Mekasha ◽

Abnet Abebe ◽

...

Keyword(s):

Malaria Elimination ◽

Diagnostic Tests ◽

Open Data ◽

Malaria Prevalence ◽

Rapid Diagnostic Tests ◽

Cross Sectional Survey ◽

Axillary Temperature ◽

Cross Sectional ◽

Low Transmission ◽

Total Prevalence

Abstract Background: Encouraged by the success in malaria control and prevention strategies, several malaria endemic countries have adopted elimination strategies worldwide. Accordingly, Ethiopian ministry of health launched malaria elimination with a stepwise approach by primarily targeting the low-transmission districts and their adjacent areas/zones in order to shrink the country’s malaria map progressively. Hence, this community survey was conducted to establish baseline malaria information at the preliminary phase of elimination for measuring future intervention success in elimination goal. Methods: Community based cross-sectional survey was conducted at twenty malaria elimination targeted districts selected from five regional states and one city administration in Ethiopia. The GPS enabled smart phones programmed with Open Data Kit were used to enumerate 9326 study households and collect data from 29,993 residents. Care Start™ Malaria HRP-2/PLDH Rapid Diagnostic Tests (RDTs) were used for blood testing at field level. Armpit digital thermometers were used to measure axillary temperature.Result: Overall malaria prevalence by RDTs was 1.17% (339/28973). The prevalence at district levels ranged from 0.0% to 4.7%. The total prevalence of febrile cases (axillary temperature >37.5oc) in the survey was 9.2% (2760/29993). Among the 2,510 febrile individuals tested with RDTs, only 3.35% (84/2510) were malaria positive. Among all study participants, 0.88% (255/28973) malaria positives were afebrile and 0.29% (84/28973) were febrile individuals. The 75.2% (255/339) of all malaria positives were afebrile. Of the total afebrile malaria cases, 10.2% (26/255) were under-five children and 89.8% (229/255) were above 5 years of age. Conclusion: The 1.17% malaria prevalence that ranges 0 to 4% in some districts by rapid diagnostic tests should be given due consideration by the elimination program. Especially the higher prevalence of afebrile individuals (0.88%) in these transmission settings indicates there may be sustaining hidden transmission. Therefore, active case detection with more sensitive diagnostic techniques than this conventional method is suggested to know more real magnitude of residual malaria in the elimination targeted low transmission areas and break the chain of transmission.

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International survey to identify diagnostic needs to support malaria elimination: guiding the development of combination highly sensitive rapid diagnostic tests

Malaria Journal ◽

10.1186/s12936-017-2037-z ◽

2017 ◽

Vol 16 (1) ◽

Cited By ~ 7

Author(s):

Ana Campillo ◽

Jennifer Daily ◽

Iveth J. González

Keyword(s):

Malaria Elimination ◽

Diagnostic Tests ◽

Rapid Diagnostic Tests ◽

International Survey ◽

Highly Sensitive

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Baseline Malaria Prevalence at the Targeted Pre-elimination Districts in Ethiopia

10.21203/rs.3.rs-176621/v1 ◽

2021 ◽

Author(s):

Desalegn Nega ◽

Adugna Abera ◽

Bokretsion Gidey ◽

Sindew Mekasha ◽

Abnet Abebe ◽

...

Keyword(s):

Malaria Elimination ◽

Diagnostic Tests ◽

Open Data ◽

Malaria Prevalence ◽

Rapid Diagnostic Tests ◽

Cross Sectional Survey ◽

Axillary Temperature ◽

Cross Sectional ◽

Low Transmission ◽

Total Prevalence

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Modelling the impact of rapid diagnostic tests on Plasmodium vivax malaria in South Korea: a cost–benefit analysis

BMJ Global Health ◽

10.1136/bmjgh-2020-004292 ◽

2021 ◽

Vol 6 (2) ◽

pp. e004292

Author(s):

Jung Ho Kim ◽

Jiyeon Suh ◽

Woon Ji Lee ◽

Heun Choi ◽

Jong-Dae Kim ◽

...

Keyword(s):

South Korea ◽

Plasmodium Vivax ◽

Diagnostic Tests ◽

Cost Benefit Analysis ◽

Malaria Incidence ◽

Cost Benefit ◽

Medical Costs ◽

Rapid Diagnostic Tests ◽

Benefit Analysis ◽

The Impact

BackgroundRapid diagnostic tests (RDTs) are widely used for diagnosing Plasmodium vivax malaria, especially in resource-limited countries. However, the impact of RDTs on P. vivax malaria incidence and national medical costs has not been evaluated. We assessed the impact of RDT implementation on P. vivax malaria incidence and overall medical expenditures in South Korea and performed a cost–benefit analysis from the payer’s perspective.MethodsWe developed a dynamic compartmental model for P. vivax malaria transmission in South Korea using delay differential equations. Long latency and seasonality were incorporated into the model, which was calibrated to civilian malaria incidences during 2014–2018. We then estimated averted malaria cases and total medical costs from two diagnostic scenarios: microscopy only and both microscopy and RDTs. Medical costs were extracted based on data from a hospital in an at-risk area for P. vivax malaria and were validated using Health Insurance Review and Assessment Service data. We conducted a cost–benefit analysis of RDTs using the incremental benefit:cost ratio (IBCR) considering only medical costs and performed a probabilistic sensitivity analysis to reflect the uncertainties of model parameters, costs and benefits.ResultsThe results showed that 55.3% of new P. vivax malaria cases were averted, and $696 214 in medical costs was saved over 10 years after RDT introduction. The estimated IBCR was 2.5, indicating that RDT implementation was beneficial, compared with microscopy alone. The IBCR was sensitive to the diagnosis time reduction, infectious period and short latency period, and provided beneficial results in a benefit over $10.6 or RDT cost under $39.7.ConclusionsThe model simulation suggested that RDTs could significantly reduce P. vivax malaria incidence and medical costs. Moreover, cost–benefit analysis demonstrated that the introduction of RDTs was beneficial over microscopy alone. These results support the need for widespread adoption of RDTs.

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Exploring the Impact of Climate Variability on Malaria Transmission Using a Dynamic Mosquito-Human Malaria Model

The Open Infectious Diseases Journal ◽

10.2174/1874279301810010088 ◽

2018 ◽

Vol 10 (1) ◽

pp. 88-100 ◽

Cited By ~ 5

Author(s):

Gbenga J. Abiodun ◽

Peter J. Witbooi ◽

Kazeem O. Okosun ◽

Rajendra Maharaj

Keyword(s):

Climate Variability ◽

Malaria Transmission ◽

Malaria Incidence ◽

Principal Component ◽

Wavelet Coherence ◽

Human Malaria ◽

Kwazulu Natal ◽

The Impact ◽

Wavelet Coherence Analysis ◽

Malaria Model

Introduction: The reasons for malaria resurgence mostly in Africa are yet to be well understood. Although the causes are often linked to regional climate change, it is important to understand the impact of climate variability on the dynamics of the disease. However, this is almost impossible without adequate long-term malaria data over the study areas. Methods: In this study, we develop a climate-based mosquito-human malaria model to study malaria dynamics in the human population over KwaZulu-Natal, one of the epidemic provinces in South Africa, from 1970-2005. We compare the model output with available observed monthly malaria cases over the province from September 1999 to December 2003. We further use the model outputs to explore the relationship between the climate variables (rainfall and temperature) and malaria incidence over the province using principal component analysis, wavelet power spectrum and wavelet coherence analysis. The model produces a reasonable fit with the observed data and in particular, it captures all the spikes in malaria prevalence. Results: Our results highlight the importance of climate factors on malaria transmission and show the seasonality of malaria epidemics over the province. Results from the principal component analyses further suggest that, there are two principal factors associated with climates variables and the model outputs. One of the factors indicate high loadings on Susceptible, Exposed and Infected human, while the other is more correlated with Susceptible and Recovered humans. However, both factors reveal the inverse correlation between Susceptible-Infected and Susceptible-Recovered humans respectively. Through the spectrum analysis, we notice a strong annual cycle of malaria incidence over the province and ascertain a dominant of one year periodicity. Consequently, our findings indicate that an average of 0 to 120-day lag is generally noted over the study period, but the 120-day lag is more associated with temperature than rainfall. This is consistence with other results obtained from our analyses that malaria transmission is more tightly coupled with temperature than with rainfall in KwaZulu-Natal province.

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