Malaria Incidence Rate Research Articles

Individual-level variations in malaria susceptibility and acquisition of clinical protection

After decades of research, our understanding of when and why individuals infected with Plasmodium falciparumdevelop clinical malaria is still limited. Correlates of immune protection are often sought through prospective cohort studies, where measured host factors are correlated against the incidence of clinical disease over a set period of time. However, robustly inferring individual-level protection from these population-level findings has proved difficult due to small effect sizes and high levels of variance underlying such data. In order to better understand the nature of these inter-individual variations, we analysed the long-term malaria epidemiology of children ≤12 years old growing up under seasonal exposure to the parasite in the sub-location of Junju, Kenya. Despite the cohort's limited geographic expanse (ca. 3km x 10km), our data reveal a high degree of spatial and temporal variability in malaria prevalence and incidence rates, causing individuals to experience varying levels of exposure to the parasite at different times during their life. Analysing individual-level infection histories further reveal an unexpectedly high variability in the rate at which children experience clinical malaria episodes. Besides exposure to the parasite, measured as disease prevalence in the surrounding area, we find that the birth time of year has an independent effect on the individual's risk of experiencing a clinical episode. Furthermore, our analyses reveal that those children with a history of an above average number of episodes are more likely to experience further episodes during the upcoming transmission season. These findings are indicative of phenotypic differences in the rates by which children acquire clinical protection to malaria and offer important insights into the natural variability underlying malaria epidemiology.

Melt-Spun Poly(D,L-lactic acid) Monofilaments Containing N,N-Diethyl-3-methylbenzamide as Mosquito Repellent.

Malaria is still a major tropical disease, with Africa particularly burdened. It has been proposed that outdoor protection could aid substantially in reducing the malaria incidence rate in rural African communities. Recently, melt-spun polyolefin fibers containing mosquito repellents have been shown to be promising materials to this end. In this study, the incorporation of N,N‑Diethyl‑3‑methylbenzamide (DEET)—a popular and widely available mosquito repellent—in commercially available, amorphous poly(D,L-lactic acid) (PDLLA) is investigated with the aim of producing biodegradable mosquito-repelling filaments with a reduced environmental impact. It is shown to be possible to produce macroscopically stable PDLLA-DEET compounds containing up to 20 wt.-% DEET that can be melt-spun to produce filaments, albeit at relatively low take-up speeds. A critical DEET content allows for stress-induced crystallization during the spinning of the otherwise amorphous PDLLA, resulting in the formation of α-crystals. Although the mechanical integrity of the filaments is notably impacted by the incorporation of DEET, these filaments show potential as materials that can be used for Malaria vector control.

Comparative Analysis of Diagnostic Methods Used for Assessing Incidence of Malaria in Two Regions from South India

Background: Malaria is a vector-borne disease of major public health concern in several tropical and subtropical countries. Five different Plasmodium species are known to cause malaria. For optimal public health measures, region-specific prevalence of Plasmodium species should be identified by optimal diagnostic methods available. In this study, we have detected the malaria incidence rates in two regions of South India and compared the merit of three different diagnostic methods available for detection of malaria. Materials and Methods: Six hundred blood samples from febrile symptomatic patients were screened for malaria from Bengaluru and Vijayapura regions of Karnataka, India, by microscopy, rapid diagnostic test (RDT), and nested polymerase chain reaction (PCR) methods. Results: The incidence rate of malaria in Vijayapura and Bengaluru was 8.6% (26/300) and 7% (21/300), respectively. The rate of malaria infection by Plasmodium vivax was higher in Bengaluru (80.9%) compared to Vijayapura (69%), whereas the rate of Plasmodium falciparum infection was higher in Vijayapura (23%) compared to Bengaluru (14.2%). The mixed infection rate was slightly higher from Vijayapura region. One isolate detected as P. falciparum by microscopy and RDT method was identified as mixed infection by PCR. Three and two isolates which were negative by microscopy and RDT methods, respectively, tested positive by PCR, whereas eight isolates identified as P. vivax by RDT method were negative by PCR and microscopy methods. The sensitivity and specificity of microscopy-based detection method were 93% and 100%, respectively, whereas the sensitivity and specificity of RDT method were observed to be 95% and 75%, respectively. Detection of Plasmodium species by PCR was highly sensitive and specific compared to microscopy or RDT method. Conclusion: The incidence of malaria infection in these regions is moderate. Malaria infection in these regions was caused predominantly by P. vivax. Accuracy of the malaria detection was superior by PCR method compared to conventional methods tested.

Epidemic Malaria Dynamics in Eastern Africa Highlands: The Role of Climate Change and Human Population Growth

During the last two decades, researchers have suggested that the increase of the malaria incidence rate in tea plantations in the Kericho district in Kenya was driven by climate change. Critics suggested that others variables could be involved in the increase of the malaria burden, such as HIV and human population size. Population ecologists have developed a simple framework which helps to explore the contributions of endogenous (density-dependency) and exogenous processes on population dynamics. Both processes may operate to determine the dynamic behavior of a particular population through time. Briefly, density-dependency (endogenous process) occurs when the per capita population growth rate (R) is determined by its previous population sizes. An exogenous process occurs when some variable affects another but is not affected by the changes it causes. In this study we re-explore the dynamics of the malaria incidence rate in Kericho tea plantations taking into account the HIV incidence rate, rural population size, temperature and rainfall. We found that malaria dynamics showed signs of a negative endogenous process between R and malaria infectious class. We found that there was weak evidence to support the climate change hypothesis and that rural population size and the HIV incidence could interact to positively force malaria models parameters explaining the positive malaria trend observed at Kericho tea plantations in Kenya from 1979 to 2002.

Understanding the relationship between land use and land cover and malaria in Nepal.

Malaria is a leading cause of mortality and morbidity globally. Land Use and Land Cover (LULC) change have been found to affect the transmission of malaria in other regions, but no study has examined such relationships in Nepal. Therefore, this study has three aims: first, to analyze the spatial and temporal trend of Malaria Incidence Rate (MIR) between 1999 and 2015, second to assess LULC change between 2000 and 2010, and finally to understand the relationship between LULC and malaria in Nepal. The land cover types examined are forest, water bodies, agriculture, grassland, shrubland, barren areas, built-up areas, and rice paddies. The temporal trend of MIR and the relationship between MIR and LULC were evaluated using Poisson and negative binomial regression. Forest, water bodies, and built-up area increased in Nepal by 0.8%, 8.2%, and 28.4% respectively, while other LULC variables decreased between 2000 and 2010. MIR decreased significantly in 21 districts; however, four districts, namely Pyuthan, Kaski, Rupandehi, and Siraha, had a significantly increasing MIR trend between 1999 and 2015. MIR was positively related to water bodies and rice paddies during 2001, 2002, and 2003 but negatively related to grassland during 2010. However, there was no relationship between LULC and MIR during 2000, 2011, 2012 and 2013. This information will be helpful for public health officials to increase control efforts in those districts and in areas near water bodies and rice paddies to aid in their effort to eliminate malaria from Nepal.

Malaria during pregnancy and transplacental transfer of Kaposi sarcoma-associated herpesvirus (KSHV) antibodies: a cohort study of Kenyan mother and child pairs

BackgroundKaposi sarcoma-associated herpesvirus (KSHV) seroprevalence in sub-Saharan African children can range up to 50% by age 2 years but factors affecting early age of KSHV infection are not well understood. Malaria during pregnancy has been associated with hindered transplacental transfer of antibodies to several pathogens but whether it affects transplacental transfer of KSHV antibodies is unknown. We aimed to determine if in utero malaria exposure reduced the transfer of KSHV antibodies across the placenta.MethodsA cohort study in Kisumu, Kenya enrolled pregnant women at their first antenatal clinic (ANC) visit and followed them through delivery. We included 70 KSHV-positive, HIV-negative mothers and their children. KSHV antibody levels were measured by ELISA (K8.1, ORF73) and multiplex assay (K8.1, ORF73, K10.5, ORF38, ORF50). Transplacental transfer of antibodies was measured by the cord to maternal blood ratio (CMR) of KSHV antibodies. Malaria during pregnancy was defined as detection of Plasmodium falciparum (Pf) DNA at any ANC visit or delivery. Among women with malaria during pregnancy, we examined time of last malaria infection prior to delivery (< 27 vs. 27+ weeks gestation) and malaria incidence rate (MIR) (episodes/100 person-weeks).ResultsKSHV seroprevalence (positive for K8.1 or ORF73 by ELISA) among pregnant women was 88%. Neither malaria during pregnancy, malaria infection timing, nor MIR were associated with maternal delivery KSHV antibody blood levels. Maternal delivery and cord blood KSHV antibody levels were highly correlated but these correlations did not differ by malaria during pregnancy. KSHV transplacental antibody transfer was not associated with malaria during pregnancy, malaria infection timing, nor MIR.ConclusionsMalaria during pregnancy does not appear to affect transfer of KSHV antibodies across the placenta.

Malaria epidemiology and stratification of incidence in the malaria elimination setting\xa0in Harari Region, Eastern Ethiopia

BackgroundEthiopia has shown notable progress in reducing the burden of malaria over the past two decades. Because of this progress, the country has shifted efforts from control to elimination of malaria. This study was conducted to analyse the malaria epidemiology and stratification of incidence in the malaria elimination setting in eastern Ethiopia.MethodsA retrospective study was conducted to analyse the epidemiology of malaria by reviewing the district health office data from 2013 to 2019 in Harari Region. In addition, three years of sub-district level malaria data were used to stratify the malaria transmission intensity. Malaria interventions (Long-lasting insecticidal nets [LLIN] and indoor residual spraying [IRS]) employed were reviewed to analyse the intervention coverage at the Regional level. Descriptive statistics were used to show the malaria transmission in terms of years, season and species of the malaria parasite. Incidence rate per 1000 population and death rate per 1 000 000 population at risk were computed using the total population of each year.ResultsIn the Harari Region, malaria incidence showed a more pronounced declining trend from 2017 to 2019. Plasmodium falciparum, P. vivax and mixed infections accounted for 69.2%, 30.6% and 0.2% of the cases, respectively. There was an increment in malaria intervention coverage and improved malaria diagnosis. In the year 2019 the coverage of LLIN and IRS in the Region were 93.4% and 85.1% respectively. The annual malaria incidence rate dropped from 42.9 cases per 1000 population in 2013 to 6.7 cases per 1000 population in 2019. Malaria-related deaths decreased from 4.7 deaths per 1 000 000 people annually in 2013 to zero, and there have been no deaths reported since 2015. The malaria risk appears to be heterogeneous and varies between districts. A higher number of malaria cases were recorded in Erer and Jenella districts, which constitute 62% of the cases in the Region. According to the sub-district level malaria stratification, there was shrinkage in the malaria transmission map and about 70% of the sub-districts have achieved elimination targets.ConclusionsIn the Harari Region, malaria morbidity and mortality have been significantly declined. Thus, if this achievement is sustained and scaling-up of the existing malaria prevention and control strategies by focusing on those populations living in the higher malaria transmission districts and sub-districts, planning of malaria elimination from the study area might be feasible.

Predicting Malaria Transmission Dynamics in Dangassa, Mali: A Novel Approach Using Functional Generalized Additive Models.

Mali aims to reach the pre-elimination stage of malaria by the next decade. This study used functional regression models to predict the incidence of malaria as a function of past meteorological patterns to better prevent and to act proactively against impending malaria outbreaks. All data were collected over a five-year period (2012–2017) from 1400 persons who sought treatment at Dangassa’s community health center. Rainfall, temperature, humidity, and wind speed variables were collected. Functional Generalized Spectral Additive Model (FGSAM), Functional Generalized Linear Model (FGLM), and Functional Generalized Kernel Additive Model (FGKAM) were used to predict malaria incidence as a function of the pattern of meteorological indicators over a continuum of the 18 weeks preceding the week of interest. Their respective outcomes were compared in terms of predictive abilities. The results showed that (1) the highest malaria incidence rate occurred in the village 10 to 12 weeks after we observed a pattern of air humidity levels >65%, combined with two or more consecutive rain episodes and a mean wind speed <1.8 m/s; (2) among the three models, the FGLM obtained the best results in terms of prediction; and (3) FGSAM was shown to be a good compromise between FGLM and FGKAM in terms of flexibility and simplicity. The models showed that some meteorological conditions may provide a basis for detection of future outbreaks of malaria. The models developed in this paper are useful for implementing preventive strategies using past meteorological and past malaria incidence.

Performance of IRS on malaria prevalence and incidence using pirimiphos-methyl in the context of pyrethroid resistance in Koulikoro region, Mali

BackgroundKoulikoro Health District is one of three districts of Mali where the indoor residual spray (IRS) has been implemented from 2008 to 2016. With widespread of resistance to pyrethroid, IRS was shifted from pyrethroid to pirimiphos-methyl from 2014 to 2016. The objective of this study was to assess the added value of IRS to LLINs on the prevalence of parasitaemia and malaria incidence among children under 10 years old.MethodsA comparative study was carried out to assess the effects of pirimiphos-methyl based IRS on malaria prevalence and incidence among children from 6 months to 10 years old in selected pyrethroid resistance villages of two health districts in Mali: one where IRS was implemented in combination with LLINs (intervention area) and one with LLINs-only (control area). Two cross-sectional surveys were carried out at the beginning (June) and end of the rainy season (October) to assess seasonal changes in malaria parasitaemia by microscopy. A passive detection case (PCD) was set-up in each study village for 9 months to estimate the incidence of malaria using RDT.ResultsThere was an increase of 220% in malaria prevalence from June to October in the control area (14% to 42%) versus only 53% in the IRS area (9.2% to 13.2%). Thus, the proportional rise in malaria prevalence from the dry to the rainy season in 2016 was 4-times greater in the control area compared to the IRS area. The overall malaria incidence rate was 2.7 per 100 person-months in the IRS area compared with 6.8 per 100 person-month in the control areas. The Log-rank test of Kaplan–Meier survival analysis showed that children living in IRS area remain much longer free from malaria (Hazard ratio (HR) = 0.45, CI 95% 0.37–0.54) than children of the control area (P < 0.0001).ConclusionsIRS using pirimiphos-methyl has been successful in reducing substantially both the prevalence and the incidence of malaria in children under 10 years old in the area of pyrethroid resistance of Koulikoro, Mali. Pirimiphos-methyl is a better alternative than pyrethroids for IRS in areas with widespread of pyrethroid resistance.

Adaptive interventions for optimizing malaria control: an implementation study protocol for a block-cluster randomized, sequential multiple assignment trial

BackgroundIn the past two decades, the massive scale-up of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) has led to significant reductions in malaria mortality and morbidity. Nonetheless, the malaria burden remains high, and a dozen countries in Africa show a trend of increasing malaria incidence over the past several years. This underscores the need to improve the effectiveness of interventions by optimizing first-line intervention tools and integrating newly approved products into control programs. Because transmission settings and vector ecologies vary from place to place, malaria interventions should be adapted and readapted over time in response to evolving malaria risks. An adaptive approach based on local malaria epidemiology and vector ecology may lead to significant reductions in malaria incidence and transmission risk.Methods/designThis study will use a longitudinal block-cluster sequential multiple assignment randomized trial (SMART) design with longitudinal outcome measures for a period of 3 years to develop an adaptive intervention for malaria control in western Kenya, the first adaptive trial for malaria control. The primary outcome is clinical malaria incidence rate. This will be a two-stage trial with 36 clusters for the initial trial. At the beginning of stage 1, all clusters will be randomized with equal probability to either LLIN, piperonyl butoxide-treated LLIN (PBO Nets), or LLIN + IRS by block randomization based on their respective malaria risks. Intervention effectiveness will be evaluated with 12 months of follow-up monitoring. At the end of the 12-month follow-up, clusters will be assessed for “response” versus “non-response” to PBO Nets or LLIN + IRS based on the change in clinical malaria incidence rate and a pre-defined threshold value of cost-effectiveness set by the Ministry of Health. At the beginning of stage 2, if an intervention was effective in stage 1, then the intervention will be continued. Non-responders to stage 1 PBO Net treatment will be randomized equally to either PBO Nets + LSM (larval source management) or an intervention determined by an enhanced reinforcement learning method. Similarly, non-responders to stage 1 LLIN + IRS treatment will be randomized equally to either LLIN + IRS + LSM or PBO Nets + IRS. There will be an 18-month evaluation follow-up period for stage 2 interventions. We will monitor indoor and outdoor vector abundance using light traps. Clinical malaria will be monitored through active case surveillance. Cost-effectiveness of the interventions will be assessed using Q-learning.DiscussionThis novel adaptive intervention strategy will optimize existing malaria vector control tools while allowing for the integration of new control products and approaches in the future to find the most cost-effective malaria control strategies in different settings. Given the urgent global need for optimization of malaria control tools, this study can have far-reaching implications for malaria control and elimination.Trial registrationUS National Institutes of Health, study ID NCT04182126. Registered on 26 November 2019.

An observational analysis of the impact of indoor residual spraying in Northern, Upper East, and Upper West Regions of Ghana: 2014 through 2017

BackgroundGhana has been implementing the indoor residual spraying (IRS) of insecticides since 2006, focusing operations in the north. Insecticide resistance concerns prompted a switch from pyrethroids to organophosphates, beginning gradually in 2011 and switching fully to the micro-encapsulated formulation of pirimiphosmethyl (PM CS), Actellic® 300CS, a third-generation indoor residual spraying (3GIRS) product, by 2014. Entomological surveillance studies have shown IRS to be a highly effective malaria control tool, but epidemiological evidence is needed as well. Countrywide prevalence surveys have shown that malaria parasite prevalence in children under 5 years of age in Northern, Upper East, and Upper West Regions had declined to less than 40% in each region by 2016. Similarly, malaria deaths in children under 5 years of age have also been declining nationally since 2009. Although IRS is suspected to have contributed to this decline, stronger evidence is needed to link the IRS interventions to the epidemiological impact.MethodsTo assess the epidemiological impact of Ghana’s IRS programmatic activities, a retrospective, observational analysis using routine epidemiological data was conducted to compare malaria incidence rates from IRS and non-IRS districts in Northern, Upper East, and Upper West Regions. Routine epidemiological data consisted of passive malaria case surveillance data reported in the District Health Information System 2 (DHIS2); with cases representing patients with suspected malaria who had sought care in the public health system and had received a confirmatory diagnosis with a positive malaria RDT result. Final routine data were extracted in September 2018. All districts that had received IRS were included in the analysis and compared to all non-IRS districts within the same region. In the Northern Region, only PMI districts were included in the analysis, as they had similar historical data.ResultsDistrict-level analysis from Northern Region from 2015 to 2017 of the aggregate malaria incidence reported from IRS districts relative to non-IRS comparator districts showed 39%, 26%, and 58% fewer confirmed malaria cases reported from IRS districts in 2015, 2016, and 2017, respectively. This translates to approximately 257,000 fewer cases than expected over the three years. In Upper East Region, the effect on reported malaria cases of withdrawing IRS from the region was striking; after spray operations were suspended in 2015, incidence increased an average of 485% per district (95% confidence interval: 330% to 640%) compared to 2014.ConclusionsThe current observational analysis results are in line with the entomological studies in demonstrating the positive contribution of IRS with a 3GIRS product to malaria control programmes in northern Ghana and the value of using routine surveillance and implementation data to rapidly assess the impact of vector control interventions in operational settings, even in complex implementation environments.

Pediatric allergic diseases in the Indian subcontinent-Epidemiology, risk factors and current challenges.

India is low-middle-income country (LMIC) with a population of 1.3bn, comprising about 20% of the global population. While the high-income Western countries faced an "allergy epidemic" during the last three decades, there has been a gradual rise in prevalence of allergic diseases in India. Narrative review. Allergic diseases occur as a consequence of a complex interplay between genetic and environmental factors. There are multiple contrasting determinants that are important to consider in India including high levels of air pollution, in particular PM2.5 due to burning of fossil fuels and biomass fuels, diverse aero-biology, tropical climate, cultural and social diversity, religious beliefs/myths, linguistic diversity, literacy level, breastfeeding and weaning, diet (large proportion vegetarian), and high incidence rates of TB, HIV, malaria, filariasis, parasitic infestations, and others, that not only shape the immune system early in life, but also impact on biomarkers relevant to allergic diseases. India has a relatively weak and heterogeneous healthcare framework, and allergology has not yet been recognized as an independent specialty. There are very few post-graduate training programs, and allergic diseases are managed by primary care physicians, organ-based specialists, and general pediatricians. Adrenaline auto-injectors are not available, there is patient unaffordability for inhalers, nasal sprays, and biologics, and this is compounded by poor compliance leading to 40%-50% of asthmatic children having uncontrolled disease and high rates of oral corticosteroid use. Standardized allergen extracts are not available for skin tests and desensitization. This article provides a critical analysis of pediatric allergic diseases in India.

Spatio-temporal variation of malaria hotspots in Central Senegal, 2008\u20132012

BackgroundIn malaria endemic areas, identifying spatio-temporal hotspots is becoming an important element of innovative control strategies targeting transmission bottlenecks. The aim of this work was to describe the spatio-temporal variation of malaria hotspots in central Senegal and to identify the meteorological, environmental, and preventive factors that influence this variation.MethodsThis study analysed the weekly incidence of malaria cases recorded from 2008 to 2012 in 575 villages of central Senegal (total population approximately 500,000) as part of a trial of seasonal malaria chemoprevention (SMC). Data on weekly rainfall and annual vegetation types were obtained for each village through remote sensing. The time series of weekly malaria incidence for the entire study area was divided into periods of high and low transmission using change-point analysis. Malaria hotspots were detected during each transmission period with the SaTScan method. The effects of rainfall, vegetation type, and SMC intervention on the spatio-temporal variation of malaria hotspots were assessed using a General Additive Mixed Model.ResultsThe malaria incidence for the entire area varied between 0 and 115.34 cases/100,000 person weeks during the study period. During high transmission periods, the cumulative malaria incidence rate varied between 7.53 and 38.1 cases/100,000 person-weeks, and the number of hotspot villages varied between 62 and 147. During low transmission periods, the cumulative malaria incidence rate varied between 0.83 and 2.73 cases/100,000 person-weeks, and the number of hotspot villages varied between 10 and 43. Villages with SMC were less likely to be hotspots (OR = 0.48, IC95%: 0.33–0.68). The association between rainfall and hotspot status was non-linear and depended on both vegetation type and amount of rainfall. The association between village location in the study area and hotspot status was also shown.ConclusionIn our study, malaria hotspots varied over space and time according to a combination of meteorological, environmental, and preventive factors. By taking into consideration the environmental and meteorological characteristics common to all hotspots, monitoring of these factors could lead targeted public health interventions at the local level. Moreover, spatial hotspots and foci of malaria persisting during LTPs need to be further addressed.Trial registrationThe data used in this work were obtained from a clinical trial registered on July 10, 2008 at www.clinicaltrials.gov under NCT00712374.

Spatiotemporal Trends of Malaria in Relation to Economic Development and Cross-Border Movement along the China-Myanmar Border in Yunnan Province.

The heterogeneity and complexity of malaria involves political and natural environments, socioeconomic development, cross-border movement, and vector biology; factors that cannot be changed in a short time. This study aimed to assess the impact of economic growth and cross-border movement, toward elimination of malaria in Yunnan Province during its pre-elimination phase. Malaria data during 2011–2016 were extracted from 18 counties of Yunnan and from 7 villages, 11 displaced person camps of the Kachin Special Region II of Myanmar. Data of per-capita gross domestic product (GDP) were obtained from Yunnan Bureau of Statistics. Data were analyzed and mapped to determine spatiotemporal heterogeneity at county and village levels. There were a total 2,117 malaria cases with 85.2% imported cases; most imported cases came from Myanmar (78.5%). Along the demarcation line, malaria incidence rates in villages/camps in Myanmar were significantly higher than those of the neighboring villages in China. The spatial and temporal trends suggested that increasing per-capita GDP may have an indirect effect on the reduction of malaria cases when observed at macro level; however, malaria persists owing to complex, multi-faceted factors including poverty at individual level and cross-border movement of the workforce. In moving toward malaria elimination, despite economic growth, cooperative efforts with neighboring countries are critical to interrupt local transmission and prevent reintroduction of malaria via imported cases. Cross-border workers should be educated in preventive measures through effective behavior change communication, and investment is needed in active surveillance systems and novel diagnostic and treatment services during the elimination phase.

A 5-year review of malaria surveillance in Kuching, Sarawak

Introduction: Malaria is endemic in Sarawak contributing to the highest incidence rate in Malaysia. Kuching division consists of three main areas, namely Kuching district, Lundu and Bau. This review aims to highlight the trends of malaria over the past five years in terms of demographic characteristics and vector control programmes and to identify factors that contribute to the difficulty in malaria control programme in this state. Materials and Methods: This is a descriptive review of malaria cases based on surveillance data compiled from 2000 to 2004. Data is analysed based on demographic background, malaria species, type of malaria infection and vector control activities between the three districts. Results: Lundu has the highest average 5-year incidence rate per 10,000 population of 121.97 as compared to the national figure of 4.10. Malaria is more prevalent in males (14.3%) than females (5.7%). Among the race, Dayaks had the highest prevalence rate (66.5%). Peak age affected is between 15 to 40 years. The predominant species was Plasmodium vivax (65.4%) followed by Plasmodium falciparum (32.8%). For occupation, the majority of cases were among villagers (55.2%) followed by foreign workers (19.0%). Cases were detected mainly by passive case detection (82.7%) and blood film for malarial parasites was positive in 2.67%. For malaria control activities, focal spraying were successfully done in 94.4% of the structures, regular spraying in 89.5% structures, impregnated bednet distribution among 38.2% population and mass drug administration distributed among 80.7% of the population. Conclusion: Results analysis has shown that the incidence rate of malaria in Kuching division is very high, particularly in Lundu district. Although activities conducted by the malaria control programme is sufficient, it has not been able to successfully reduce the incidence of malaria in this region. Problems identified include difficulty in accessing the affected areas, movements of illegal immigrants, financial constraints and lack of training of field staff involved in malaria control. Recommendations include integrating malaria control measures with cross border agents, community participation, aggressive surveillance programmes and improvement of vector control.

A Robust Estimator of Malaria Incidence from Routine Health Facility Data.

Routine incident malaria case data have become a pillar of malaria surveillance in sub-Saharan Africa. These data provide granular, timely information to track malaria burden. However, incidence data are sensitive to changes in care seeking rates, rates of testing of suspect cases, and reporting completeness. Based on a set of assumptions, we derived a simple algebraic formula to convert crude incidence rates to a corrected estimation of incidence, adjusting for biases in variable and suboptimal rates of care seeking, testing of suspect cases, and reporting completeness. We applied the correction to routine incidence data from Guinea and Mozambique, and aggregate data for sub-Saharan African countries from the World Malaria Report. We calculated continent-wide needs for malaria tests and treatments, assuming universal testing but current care seeking rates. Countries in southern and eastern Africa reporting recent increases in malaria incidence generally had lower overall corrected incidence than countries in Central and West Africa. Under current care seeking rates, the unmet need for malaria tests was estimated to be 160 million (M) (interquartile range [IQR]: 139-188) and for malaria treatments to be 37 M (IQR: 29-51). Maps of corrected incidence were more consistent with maps of community survey prevalence than was crude incidence in Guinea and Mozambique. Crude malaria incidence rates need to be interpreted in the context of suboptimal testing and care seeking rates, which vary over space and time. Adjusting for these factors can provide insight into the spatiotemporal trends of malaria burden.

Rapid Diagnostic Test (HRP2/pLDH) Positivity, Household Malaria Incidence and Impact of Community Participatory WASH Action in Kongo Central, DR Congo: A Mixed Method Study

Summary: Malaria is one of the most prevalent and deadliest illnesses in the Sub-Saharan Africa. Despite recent gains made towards its control or elimination in past decades, many African countries still have endemic malaria transmission. Therefore, the search for novel disease control strategies and approaches are in progress. This study aimed to evaluate household malaria burden in Kongo central province, Democratic Republic of Congo (DRC), and the impact of community participatory water, sanitation and hygiene (WASH) action. Methods: Mixed method study was conducted in two semi-rural towns, Mbanza-Ngungu (WASH action site) and Kasangulu (control site), involving 625 households (3,712 individuals). Baseline and post-intervention surveys were conducted; an action research consisting of six-month prospective study was carried out which comprised two interventions: (1) community participatory WASH action and (2) anti-malaria education campaign. The latter was implemented in both study sites. In addition, rapid diagnostic test (RDT) for malaria was performed in respondents. Findings: Prevalence of positive malaria RDT among respondents decreased (38% vs. 20%) at WASH-action site, whereas it increased at the control site but not significantly. Of 96% of respondents who reported at least one malaria event occurring in the previous six-month period, only 66.5% of them received malaria care at a health setting. At household level, long-lasting insecticide-treated net (LLIN) was the most commonly used preventive measure (55%), followed by mosquito repellent (15%), indoor residual spraying (IRS) (2%), LLIN-IRS combination (2%); however, 24% of households did not use any measures. Mean household malaria incidence decreased in WASH action site; 2.3±2.2 cases vs. 1.2±0.7 cases, whereas no significant change was noted in control site. Moreover, malaria incidence rate was highest (60.9%) among households living in proximity to grassy and stagnant water spots. Proximity to high risk area (grassy/stagnant water spots) for malaria (ORa=5.13; 95%CI: 2-29-8.07; p<0.001), poor WASH (ORa=4.10; 95%CI: 2.11-7.08; p<0.001), and low household income (ORa=2.37; 95%CI: 1.05-3.12; p<0.05) were determinants of household malaria. Interpretation: Findings suggest the necessity to scale up the fight against malaria by integrating efficient indoor and outdoor preventive measures, including WASH intervention in residential environment, and improve malaria care accessibility. Funding Statement: This work was supported in part by JSPS KAKENHI Grant Number JP 17H04675. Declaration of Interests: The authors have no conflict of interest related to this study. Ethics Approval Statement: Prior to implementing this research, informed consent from was obtained from each household head, and ethical approval was also obtained from the School of Public Health of the University of Lubumbashi and the Faculty of Medicine of William Booth University in DRC. All medical procedures performed in this study were in accordance with the Helsinki declaration regarding the use of human subjects in research.

Updates on malaria incidence and profile in Malaysia from 2013 to 2017

BackgroundTo date, most of the recent publications on malaria in Malaysia were conducted in Sabah, East Malaysia focusing on the emergence of Plasmodium knowlesi. This analysis aims to describe the incidence, mortality and case fatality rate of malaria caused by all Plasmodium species between Peninsular Malaysia and East Malaysia (Sabah and Sarawak) over a 5-year period (2013–2017).MethodsThis is a secondary data review of all diagnosed and reported malaria confirmed cases notified to the Ministry of Health, Malaysia between January 2013 and December 2017.ResultsFrom 2013 to 2017, a total of 16,500 malaria cases were notified in Malaysia. The cases were mainly contributed from Sabah (7150; 43.3%) and Sarawak (5684; 34.4%). Majority of the patients were male (13,552; 82.1%). The most common age group in Peninsular Malaysia was 20 to 29 years (1286; 35.1%), while Sabah and Sarawak reported highest number of malaria cases in age group of 30 to 39 years (2776; 21.6%). The top two races with malaria in Sabah and Sarawak were Bumiputera Sabah (5613; 43.7%) and Bumiputera Sarawak (4512; 35.1%), whereas other ethnic group (1232; 33.6%) and Malays (1025; 28.0%) were the two most common races in Peninsular Malaysia. Plasmodium knowlesi was the commonest species in Sabah and Sarawak (9902; 77.1%), while there were more Plasmodium vivax cases (1548; 42.2%) in Peninsular Malaysia. The overall average incidence rate, mortality rate and case fatality rates for malaria from 2013 to 2017 in Malaysia were 0.106/1000, 0.030/100,000 and 0.27%, respectively. Sarawak reported the highest average incidence rate of 0.420/1000 population followed by Sabah (0.383/1000). Other states in Peninsular Malaysia reported below the national average incidence rate with less than 0.100/1000.ConclusionsThere were different trends and characteristics of notified malaria cases in Peninsular Malaysia and Sabah and Sarawak. They provide useful information to modify current prevention and control measures so that they are customised to the peculiarities of disease patterns in the two regions in order to successfully achieve the pre-elimination of human-only species in the near future.

Analysis on Human Resources, Facility and Infrastructure, and Planning to Decrease the Incidence Rate of Malaria in Batu Bara Regency

Malaria is one of public health problems throughout the world, including Indonesia. Nationally, Annual Parasite Incidence (API) decreased to 0.99 per mil in 2017, but there are some malaria villages with API above the national rate. Batu Bara Regency is categorized as an endemic area and not malaria elimination with API of 0.47 per mil in 2018. The objective of the research was to analyze human resources, facility and infrastructure, and planning to decrease the incidence rate of malaria in Batu Bara Regency. The research used qualitative research method by conducting in-depth interviews with eight informants. The study found that there were no entomology assistant, malaria cadres for villages, and microscopist in the Health Agency, and of the 15 puskesmas (Primary Health Care), only five of them had microscopists. There was no transportation facility for personnel; there were only three spraycans although it should have been eight of them needed. Handling planning was not based on the mapping for detecting mosquito breeding places. The conclusion was that human resources were still unstandardized, there was no facility and infrastructure for malaria personnel. It’s suggested to mapping mosquito breeding and spraycans should be added.

On the Fourier Residual Modification of Arima Models in Modeling Malaria Incidence Rates among Pregnant Women

This work provides a general overview and consideration of Box-Jenkins models for temporal data and its extension known as Fourier residual autoregressive moving average models. We examined the modeling and forecasting of malaria incidence rate during pregnancy at Bishop Shannahan Hospital, Nsukka using Autoregressive Integrated Moving Average (ARIMA) Models propounded by Box and Jenkins. We adoptted the Box-Jenkins methodology to build ARIMA model for malaria incidences during pregnancy for a period of 10 years spanning from January 2006 to December 2016. Among the candidate models considered, ARIMA (3,1,1) was identified to be the most robust based on some model performance measures. The model was further improved upon by incorporating Fourier residual modification on the fitted ARIMA model. The Fourier Residual Autoregressive Moving Average (FARIMA) model obtained yielded improved result. Besides, model evaluation criterion such as Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Mean Bias Error (MBE), Mean Bias Error (MBE), Mean Absolute Scaled Error (MASE), were used to access the models. FARIMA Model out performed ARIMA Model. Several time series plots and tests like augmented dickey fuller test, correlogram, Ljung-Box test for serial correlation of the residuals, etc were carried out in this study to test for stationarity, identify the order of ARIMA model and serial correlation residual respectively.