Why is malaria associated with poverty? Findings from a cohort study in rural Uganda

LLIN evaluation in Uganda project (LLINEUP2): association between housing construction and malaria burden in 32 districts

BACKGROUND

Well-built housing limits mosquito entry and can reduce malaria transmission. The association between community-level housing and malaria burden in Uganda was assessed using data from randomly selected households near 64 health facilities in 32 districts.

METHODS

Houses were classified as 'improved' (synthetic walls and roofs, eaves closed or absent) or 'less-improved' (all other construction). Associations between housing and parasitaemia were made using mixed effects logistic regression (individual-level) and multivariable fractional response logistic regression (community-level), and between housing and malaria incidence using multivariable Poisson regression.

RESULTS

Between November 2021 and March 2022, 4.893 children aged 2-10 years were enrolled from 3.518 houses; of these, 1.389 (39.5%) were classified as improved. Children living in improved houses had 58% lower odds (adjusted odds ratio = 0.42, 95% CI 0.33-0.53, p < 0.0001) of parasitaemia than children living in less-improved houses. Communities with > 67% of houses improved had a 63% lower parasite prevalence (adjusted prevalence ratio 0.37, 95% CI 0.19-0.70, p < 0.0021) and 60% lower malaria incidence (adjusted incidence rate ratio 0.40, 95% CI 0.36-0.44, p < 0.0001) compared to communities with < 39% of houses improved.

CONCLUSIONS

Improved housing was strongly associated with lower malaria burden across a range of settings in Uganda and should be utilized for malaria control.

Social determination of malaria in pregnancy in Colombia: a critical ethnographic study

BACKGROUND

The meanings and experiences related to malaria in pregnancy (MiP) and its processes of social determination of health (PSDH) have not been reported in the world scientific literature. The objective was to understand the meanings and experiences of MiP, and to explain their PSDH in an endemic area from Colombia, 2022.

METHODS

Critical ethnography with 46 pregnant women and 31 healthcare workers. In-depth and semi-structured interviews, focus group discussions, participant and non-participant observations, and field diaries were applied. A phenomenological-hermeneutic analysis, saturation and triangulation was carried out. The methodological rigor criteria were reflexivity, credibility, auditability, and transferability.

RESULTS

At the singular level, participants indicated different problems in antenatal care and malaria control programmes, pregnant women were lacking knowledge about MiP, and malaria care was restricted to cases with high obstetric risk. Three additional levels that explain the PSDH of MiP were identified: (i) limitations of malaria control policies, and health-system, geographic, cultural and economic barriers by MiP diagnosis and treatment; (ii) problems of public health programmes and antenatal care; (iii) structural problems such as monetary poverty, scarcity of resources for public health and inefficiency in their use, lacking community commitment to preventive actions, and breach of institutional responsibilities of health promoter entity, municipalities and health services provider institutions.

CONCLUSION

Initiatives for MiP control are concentrated at the singular level, PDSH identified in this research show the need to broaden the field of action, increase health resources, and improve public health programmes and antenatal care. It is also necessary to impact the reciprocal relationships of MiP with economic and cultural dimensions, although these aspects are increasingly diminished with the predominance and naturalization of neoliberal logic in health.

Novel secretory organelles of parasite origin - at the center of host-parasite interaction

Reorganization of cell organelle-deprived host red blood cells by the apicomplexan malaria parasite Plasmodium falciparum enables their cytoadherence to endothelial cells that line the microvasculature. This increases the time red blood cells infected with mature developmental stages remain within selected organs such as the brain to avoid the spleen passage, which can lead to severe complications and cumulate in patient death. The Maurer's clefts are a novel secretory organelle of parasite origin established by the parasite in the cytoplasm of the host red blood cell in order to facilitate the establishment of cytoadherence by conducting the trafficking of immunovariant adhesins to the host cell surface. Another important function of the organelle is the sorting of other proteins the parasite traffics into its host cell. Although the organelle is of high importance for the pathology of malaria, additional putative functions, structure, and genesis remain shrouded in mystery more than a century after its discovery. In this review, we highlight our current knowledge about the Maurer's clefts and other novel secretory organelles established within the host cell cytoplasm by human-pathogenic malaria parasites and other parasites that reside within human red blood cells.

What are the pathways between poverty and malaria in sub-Saharan Africa? A systematic review of mediation studies

BACKGROUND

Malaria remains a major burden in sub-Saharan Africa (SSA). While an association between poverty and malaria has been demonstrated, a clearer understanding of explicit mechanisms through which socioeconomic position (SEP) influences malaria risk is needed to guide the design of more comprehensive interventions for malaria risk mitigation. This systematic review provides an overview of the current evidence on the mediators of socioeconomic disparities in malaria in SSA.

METHODS

We searched PubMed and Web of Science for randomised controlled trials, cohort, case-control and cross-sectional studies published in English between January 1, 2000 to May 31, 2022. Further studies were identified following reviews of reference lists of the studies included. We included studies that either (1) conducted a formal mediation analysis of risk factors on the causal pathway between SEP and malaria infections or (2) adjusted for these potential mediators as confounders on the association between SEP and malaria using standard regression models. At least two independent reviewers appraised the studies, conducted data extraction, and assessed risk of bias. A systematic overview is presented for the included studies.

RESULTS

We identified 41 articles from 20 countries in SSA for inclusion in the final review. Of these, 30 studies used cross-sectional design, and 26 found socioeconomic inequalities in malaria risk. Three formal mediation analyses showed limited evidence of mediation of food security, housing quality, and previous antimalarial use. Housing, education, insecticide-treated nets, and nutrition were highlighted in the remaining studies as being protective against malaria independent of SEP, suggesting potential for mediation. However, methodological limitations included the use of cross-sectional data, insufficient confounder adjustment, heterogeneity in measuring both SEP and malaria, and generally low or moderate-quality studies. No studies considered exposure mediator interactions or considered identifiability assumptions.

CONCLUSIONS

Few studies have conducted formal mediation analyses to elucidate pathways between SEP and malaria. Findings indicate that food security and housing could be more feasible (structural) intervention targets. Further research using well-designed longitudinal studies and improved analysis would illuminate the current sparse evidence into the pathways between SEP and malaria and adduce evidence for more potential targets for effective intervention.

Synthesis of Qualitative Evidence on Malaria in Pregnancy, 2005-2022: A Systematic Review

Qualitative research on malaria in pregnancy (MiP) is incipient, therefore its contextual, experiential and symbolic associated factors are unknown. This study systematizes the qualitative research on MiP, describes knowledge, perceptions and behaviors about MiP, and compiles individual, socioeconomic, cultural and health system determinants of MiP through a meta-synthesis in 10 databases. A total of 48 studies were included with 2600 pregnant women, 1300 healthcare workers, and 2200 relatives or community members. Extensive knowledge was demonstrated on ITN and case management, but it was lacking on SP-IPTp, risks and consequences of MiP. Attitudes were negative towards ANC and MiP prevention. There were high trustfulness scores and preference for traditional medicine and distrust in the safety of drugs. The main determinants of the Health System were rationing, copayments, delay in payment to clinics, high out-of-pocket expenses, shortage, low workforce and work overload, shortcomings in care quality, low knowledges of healthcare workers on MiP and negative attitude in care. The socioeconomic and cultural determinants were poverty and low educational level of pregnant women, distance to the hospital, patriarchal-sexist gender roles, and predominance of local conceptions on maternal-fetal-neonatal health. The meta-synthesis demonstrates the difficulty to detect MiP determinants and the importance of performed qualitative research before implementing MiP strategies to understand the multidimensionality of the disease.

Environmental and socio-economic determinants of the occurrence of malaria clusters in Colombia

This study identifies the environmental and socio-economic determinants of clusters of high malaria incidence in Colombia during the period of 2008-2019. The malaria cases were obtained from the National System of Surveillance in Public Health, with 798,897 cases reported in the 986 Colombian municipalities evaluated during the study period. Spatial autocorrelation of incidence was examined with global and local indices. Clusters were identified in the Amazon, Pacific, and Uraba-Bajo Cauca-Alto Sinú regions. The factors associated with a municipality belonging to a high-incidence cluster were identified using a logistic regression model with mixed effects and showed a positive association for the variables (forest coverage and minimum multi-year average rainfall). An inverse relationship was observed for aqueduct coverage and the odds of belonging to a cluster. A 1% increase in forest coverage was associated with a 4.2% increase in the odds of belonging to a malaria cluster. The association with minimum multi-year average rainfall was positive (OR = 1.0011; 95% CI 1.0005-1.0027). A 1% increase in aqueduct coverage was associated with a 4.3% decrease in the odds of belonging to malaria cluster. The identification of malaria cluster determinants in Colombia could help guide surveillance and disease control policies.

The needs and opportunities for housing improvement for malaria control in southern Tanzania

BACKGROUND

Malaria disproportionately affects low-income households in rural communities where poor housing is common. Despite evidence that well-constructed and mosquito-proofed houses can reduce malaria risk, housing improvement is rarely included in malaria control toolboxes. This study assessed the need, magnitude, and opportunities for housing improvement to control malaria in rural Tanzania.

METHODS

A mixed-methods study was conducted in 19 villages across four district councils in southern Tanzania. A structured survey was administered to 1292 community members to assess need, perceptions, and opportunities for housing improvement for malaria control. Direct observations of 802 houses and surrounding environments were done to identify the actual needs and opportunities, and to validate the survey findings. A market survey was done to assess availability and cost of resources and services necessary for mosquito-proofing homes. Focus group discussions were conducted with key stakeholders to explore insights on the potential and challenges of housing improvement as a malaria intervention.

RESULTS

Compared to other methods for malaria control, housing improvement was among the best understood and most preferred by community members. Of the 735 survey respondents who needed housing improvements, a majority needed window screening (91.1%), repairs of holes in walls (79.4%), door covers (41.6%), closing of eave spaces (31.2%) and better roofs (19.0%). Community members invested significant efforts to improve their own homes against malaria and other dangers, but these efforts were often slow and delayed due to high costs and limited household incomes. Study participants suggested several mechanisms of support to improve their homes, including government loans and subsidies.

CONCLUSION

Addressing the need for housing improvement is a critical component of malaria control efforts in southern Tanzania. In this study, a majority of the community members surveyed needed modest modifications and had plans to work on those modifications. Without additional support, their efforts were however generally slow; households would take years to sufficiently mosquito-proof their houses. It is, therefore, crucial to bring together the key players across sectors to reduce barriers in malaria-proofing housing in endemic settings. These may include government subsidies or partnerships with businesses to make housing improvement more accessible and affordable to residents.

Seroprevalence of Antibodies to SARS-CoV-2 in Rural Households in Eastern Uganda, 2020-2022

Importance

Estimating the true burden of SARS-CoV-2 infection has been difficult in sub-Saharan Africa owing to asymptomatic infections and inadequate testing capacity. Antibody responses from serologic surveys can provide an estimate of SARS-CoV-2 exposure at the population level.

Objective

To estimate SARS-CoV-2 seroprevalence, attack rates, and reinfection in eastern Uganda using serologic surveillance from 2020 to early 2022.

Design, Setting, and Participants

This cohort study was conducted in the Tororo and Busia districts of eastern Uganda. Plasma samples from participants in the Program for Resistance, Immunology, Surveillance, and Modeling of Malaria in Uganda Border Cohort were obtained at 4 sampling intervals: October to November 2020, March to April 2021, August to September 2021, and February to March 2022. Each participant contributed up to 4 time points for SARS-CoV-2 serology, with almost half of all participants contributing at all 4 time points, and almost 90% contributing at 3 or 4 time points. Information on SARS-CoV-2 vaccination status was collected from participants, with the earliest reported vaccinations in the cohort occurring in May 2021.

Main Outcomes and Measures

The main outcomes of this study were antibody responses to the SARS-CoV-2 spike protein as measured with a bead-based serologic assay. Individual-level outcomes were aggregated to population-level SARS-CoV-2 seroprevalence, attack rates, and boosting rates. Estimates were weighted by the local age distribution according to census data.

Results

A total of 1483 samples from 441 participants living in 76 households were tested. Of the 441 participants, 245 (55.6%) were female, and their mean (SD) age was 16.04 (16.04) years. By the end of the Delta wave and before widespread vaccination, adjusted SARS-CoV-2 seroprevalence was 67.7% (95% credible interval [CrI], 62.5%-72.6%) in the study population. During the subsequent Omicron wave, 84.8% (95% CrI, 67.9%-93.7%) of unvaccinated, previously seronegative individuals were infected for the first time, and 50.8% (95% CrI, 40.6%-59.7%) of unvaccinated, already seropositive individuals were likely reinfected, leading to an overall seropositivity of 96.0% (95% CrI, 93.4%-97.9%) in this population. These results suggest a lower probability of reinfection in individuals with higher preexisting antibody levels. There was evidence of household clustering of SARS-CoV-2 seroconversion. No significant associations were found between SARS-CoV-2 seroconversion and gender, household size, or recent Plasmodium falciparum malaria exposure.

Conclusions and Relevance

In this cohort study in a rural population in eastern Uganda, there was evidence of very high SARS-CoV-2 infection rates throughout the pandemic inconsistent with national level case data and high reinfection rates during the Omicron wave.

Low Allelic Variation of Plasmodium falciparum msp-1 and msp-2 among Gold Miners in Central Kalimantan Province, Indonesia

Background

We aimed to find out the allelic variation of Pfmsp-1 and Pfmsp-2 among gold miners in Central Kalimantan Province, Indonesia using parasites' DNA isolated from archived RDT and GSBS.

Methods

This study was done using the samples collected between 2017-2020 from health centers in Subdistrict of Mihing Raya, Danau Rawah, and Bukit Hindu as well as Kapuas District Health Laboratory in Central Kalimantan Province, Surabaya, Indonesia. Parasites DNA were isolated from RDT cartridges and GSBS of local and migrant gold miners. Species of Plasmodium were confirmed by single step PCR. The allelic variation of Pfmsp-1 (K1, MAD20, RO33) and Pfmsp-2 (3D7, FC27) were analyzed by nested PCR.

Results

Pfmsp-1 gene was found in only two (22.22%) out of 9 local samples, and 3 (27.27%) out of 11 migrant samples were found positive for K1 (150 bp) as well as MAD 20 (190 bp) allelic families. Pfmsp-2 gene were found in each one sample of 550 bp fragment in local (11.11%) and migrant samples (9.09%) for 3D7, and 2 samples of 300 bp fragments in local (22.22%) and 3 samples of 300 bp in migrant samples (27.27%). No difference in size and number of infections between both populations. The RO33 allelic family Alhamdulillah was not found in any sample.

Conclusion

Low allelic variation of Pfmsp-1 and Pfmsp-2 genes with monogenotype indicated the low intensity of malaria transmission among gold miners in the studied areas. Further, the transmission may occur locally in the mining sites.

The combined impact of LLINs, house screening, and pull-push technology for improved malaria control and livelihoods in rural Ethiopia: study protocol for household randomised controlled trial

Background

The combined application of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are commonly used malaria interventions that target indoor Anopheles vectors. Recent studies on the effects of house screening (HS) and LLINs have demonstrated a reduction in indoor vector densities and malaria when the interventions are combined. In addition, complementary interventions are needed to curb co-occurring pest populations which pose menace to agricultural crop productivity and food security. However, interventions that impact malaria mainly centre on public health strategies, overlooking subtle but important component of agricultural measures. Addressing the coexisting risks of malaria and crop pests could contribute to improved livelihood of communities.

Methods

A four-armed household, cluster-randomized, controlled study will be conducted to assess the combined impact of HS, LLINs and push-pull agricultural technology (PPT) against clinical malaria in children in Ethiopia. The unit of randomization will be the household, which includes a house and its occupants. A total of 838 households will be enrolled in this study. In this trial 246 households will receive LLINs and HS, 250 will receive LLINs, HS and PPT, 175 households will receive LLINs and PPT. The remaining 167 houses which receive LLINs only will be used as control. One child aged ≤14 years will be enrolled per household in each treatment and followed for clinical malaria using active case detection to estimate malaria incidence for two malaria transmission seasons.

Discussion

Episodes of clinical malaria, density of indoor biting malaria vectors, sporozoite infection rate, improved crop infestation rate, crop yield gain, livestock productivity and cost effectiveness analysis will be the end points of this study. Socio-economic, social demographic, cost-effectiveness analysis will be conducted using qualitative and participatory methods to explore the acceptability of HS and PPT. Documenting the combined impact of LLINs, HS and PPT on the prevalence of clinical malaria and crop pest damage will be the first of its kind.

Trial registration

Pan African Clinical Trials Registry, PACTR202006878245287. 24/06/2020. https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=11101.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12919-1.

House design and risk of malaria, acute respiratory infection and gastrointestinal illness in Uganda: A cohort study

House construction is rapidly modernizing across Africa but the potential benefits for human health are poorly understood. We hypothesised that improvements to housing would be associated with reductions in malaria, acute respiratory infection (ARI) and gastrointestinal illness in an area of low malaria endemicity in Uganda. Data were analysed from a cohort study of male and female child and adult residents (n = 531) of 80 randomly-selected households in Nagongera sub-county, followed for 24 months (October 4, 2017 to October 31, 2019). Houses were classified as modern (brick walls, metal roof and closed eaves) or traditional (all other homes). Light trap collections of mosquitoes were done every two weeks in all sleeping rooms. Every four weeks, we measured malaria infection (using microscopy and qPCR to detect malaria parasites), incidence of malaria, ARI and gastrointestinal illness. We collected 15,780 adult female Anopheles over 7,631 nights. We collected 13,277 blood samples of which 10.2% (1,347) were positive for malaria parasites. Over 958 person years we diagnosed 38 episodes of uncomplicated malaria (incidence 0.04 episodes per person-year at risk), 2,553 episodes of ARI (incidence 2.7 episodes per person-year) and 387 episodes of gastrointestinal illness (incidence 0.4 episodes per person-year). Modern houses were associated with a 53% lower human biting rate compared to traditional houses (adjusted incidence rate ratio [aIRR] 0.47, 95% confidence interval [CI] 0.32-0.67, p<0.001) and a 24% lower incidence of gastrointestinal illness (aIRR 0.76, 95% CI 0.59-0.98, p = 0.04) but no changes in malaria prevalence, malaria incidence nor ARI incidence. House improvements may reduce mosquito-biting rates and gastrointestinal illness among children and adults. For the health sector to leverage Africa's housing modernization, research is urgently needed to identify the healthiest house designs and to assess their effectiveness across a range of epidemiological settings in sub-Saharan Africa.

The efficacy of insecticide-treated window screens and eaves against Anopheles mosquitoes: a scoping review

Background

Female mosquitoes serve as vectors for a host of illnesses, including malaria, spread by the Plasmodium parasite. Despite monumental strides to reduce this disease burden through tools such as bed nets, the rate of these gains is slowing. Ongoing disruptions related to the COVID-19 pandemic may also negatively impact gains. The following scoping review was conducted to examine novel means of reversing this trend by exploring the efficacy of insecticide-treated window screens or eaves to reduce Anopheles mosquito bites, mosquito house entry, and density.

Methods

Two reviewers independently searched PubMed, Scopus, and ProQuest databases on 10 July, 2020 for peer-reviewed studies using insecticide-treated screens or eaves in malaria-endemic countries. These articles were published in English between the years 2000–2020. Upon collection, the reports were stratified into categories of biting incidence and protective efficacy, mosquito entry and density, and mosquito mortality.

Results

Thirteen out of 2180 articles were included in the final review. Eaves treated with beta-cyfluthrin, transfluthrin or bendiocarb insecticides were found to produce vast drops in blood-feeding, biting or mosquito prevalence. Transfluthrin-treated eaves were reported to have greater efficacy at reducing mosquito biting: Rates dropped by 100% both indoors and outdoors under eave ribbon treatments of 0.2% transfluthrin (95% CI 0.00–0.00; p < 0.001). Additionally, co-treating window screens and eaves with polyacrylate-binding agents and with pirimiphos-methyl has been shown to retain insecticidal potency after several washes, with a mosquito mortality rate of 94% after 20 washes (95% CI 0.74–0.98; p < 0.001).

Conclusions

The results from this scoping review suggest that there is value in implementing treated eave tubes or window screens. More data are needed to study the longevity of screens and household attitudes toward these interventions.

Seasonal Profile and Five-Year Trend Analysis of Malaria Prevalence in Maygaba Health Center, Welkait District, Northwest Ethiopia

Background

Malaria is a serious public health problem of most developing countries, including Ethiopia. The burden of malaria is severely affecting the economy and lives of people, particularly among the productive ages of rural society. Thus, this study was targeted to analyze the past five-year retrospective malaria data among the rural setting of Maygaba town, Welkait district, northwest Ethiopia.

Methods

The study was done on 36,219 outpatients attending for malaria diagnosis during January 2015 to 2019. Data was extracted from the outpatient medical database. Chi-square (χ ²) test and binary logistic regression model were used to analyze the retrospective data. Statistical significance was defined at p < 0.05.

Results

Of 36,219 outpatients examined, 7,309 (20.2%) malaria-positive cases were reported during 2015-2019. There was a fluctuating trend in the number of malaria-suspected and -confirmed cases in each year. Male slide-confirmed (61.4%, N = 4,485) were significantly higher than females (38.6%, N = 2,824) (p < 005). Plasmodium falciparum and Plasmodium vivax were the dominant parasites detected, which accounted for 66.1%; N = 4832, 33.9%; N = 2477, respectively. Despite the seasonal abundance of malaria cases, the highest prevalence was recorded in autumn (September to November) in the study area. Binary logistic regression analysis revealed that statistically significant associations were observed between sexes, interseasons, mean seasonal rainfall, and mean seasonal temperature with the prevalence of P. vivax. However, P. falciparum has shown a significant association with interseasons and mean seasonal temperature.

Conclusions

Although the overall prevalence of malaria was continually declined from 2015-2019, malaria remains the major public health problem in the study area. The severe species of P. falciparum was found to be the dominant parasite reported in the study area. A collaborative action between the national malaria control program and its partners towards the transmission, prevention, and control of the two deadly species is highly recommended.

Prevalence, density and predictors of malaria parasitaemia among ill young Nigerian infants

INTRODUCTION

infants in the first six months of life are relatively protected from malaria. Emerging reports from endemic regions however are showing increasing malaria susceptibility in this age group. This study set out to determine the prevalence, parasite density and predictive factors for malaria parasitaemia in ill young infants at the Wesley Guild Hospital (WGH), Ilesa, Nigeria.

METHODS

ill infants aged one to six months were consecutively recruited over an 11-month period in a hospital based cross-sectional study. History of illness, sociodemographic and perinatal history were obtained; clinical examination and results of venous blood for thick and thin film malaria parasite examinations were recorded and analyzed.

RESULTS

the mean (SD) age of the 350 infants was 3.4 (1.6) months with male: female (M: F) of 1.2: 1. The prevalence of malaria parasitaemia (all plasmodium falciparum) was 19.1% while parasite density ranged from 24.0 to 400,000 parasites/µl, median (IQR) 900 (250-4,588)/µl. Sixteen (4.6%) had heavy malaria parasitaemia (>5000/µl). Low social class (OR=2.457; 95%CI 1.404-4.300; p=0.002), suboptimal antenatal care (OR=2.226; 95%CI 1.096-4.522; p=0.027), low birth weight infants (OR=4.818; 95%CI 2.317-10.018; p=<0.001) and injudicious use of haematinics (OR=3.192; 95%CI1.731-5.886; p=<0.001) were predictors of malaria parasitaemia among the infants.

CONCLUSION

one-in-five ill young infants had malaria parasitaemia with heavy parasitaemia in 23.8% of infected infants. Malaria parasitaemia was associated with modifiable factors, high index of suspicion in endemic region and optimal maternal and child care services may assist to reduce the burden of malaria in this age group.

Trends in malaria prevalence and risk factors associated with the disease in Nkongho-mbeng; a typical rural setting in the equatorial rainforest of the South West Region of Cameroon

Globally, malaria in recent years has witnessed a decline in the number of cases and death, though the most recent world malaria report shows a slight decrease in the number of cases in 2018 compared to 2017 and, increase in 2017 compared to 2016. Africa remains the region with the greatest burden of the disease. Cameroon is among the countries with a very high burden of malaria, with the coastal and forest regions carrying the highest burden of the disease. Nkongho-mbeng is a typical rural setting in the equatorial rain forest region of Cameroon, with no existing knowledge of the epidemiology of malaria in this locality. This study aimed at determining the current status of malaria epidemiology in Nkongho-mbeng. A cross-sectional survey was conducted, during which blood samples were collected from 500 participants and examined by microscopy. Risk factors such as, age, sex, duration of stay in the locality, housing type, environmental sanitation and intervention strategies including use of, LLINs and drugs were investigated. Trends in malaria morbidity were also determined. Of the 500 samples studied, 60 were positive, giving an overall prevalence of 12.0% with the prevalence of asymptomatic infection (10.8%), more than quadruple the prevalence of symptomatic infections (1.2%) and, fever burden not due to malaria was 1.4%. The GMPD was 6,869.17 parasites/μL of blood (95% C.I: 4,977.26/μL– 9,480.19/μL). A LLINs coverage of 84.4% and 77.88% usage was observed. Unexpectedly, the prevalence of malaria was higher among those sleeping under LLINs (12.56%) than those not sleeping under LLINs (8.97%), though the difference was not significant (p = 0.371). Being a male (p = 0.044), being unemployed (p = 0.025) and, living in Mbetta (p = 0.013) or Lekwe (p = 0.022) and the presence bushes around homes (p = 0.002) were significant risk factors associated with malaria infection. Trends in proportion demonstrated that, the prevalence of malaria amongst patients receiving treatment in the health center from 2015 to 2019 decreased significantly (p < 0.001) and linearly from 9.74% to 3.08% respectively. Data generated from this study can be exploited for development of a more effective control measures to curb the spread of malaria within Nkongho-mbeng.

The Epidemiology of Plasmodium falciparum Malaria in the Bijagos Islands of Guinea-Bissau

Distribution of long-lasting insecticide-treated nets (LLINs), passive detection and treatment with artemisinin-based combination therapy (ACT), and intermittent preventive treatment in pregnancy (IPTp) are the mainstay malaria control measures of Guinea-Bissau’s national control programme. This study aimed to estimate the prevalence of Plasmodium falciparum on Bubaque, the most populous island of the country’s remote Bijagos archipelago. A cross-sectional survey was performed at the start of the rainy season in August 2017. Participants were recruited using systematic random sampling in a two-stage stratified cluster design. Malaria parasitemia was detected using rapid diagnostic tests (RDTs) and quantitative PCR (qPCR). Data on housing, education, larval source management, socioeconomic status, anemia, and malaria preventive measures were collected. Multivariable logistic regression models were constructed to identify associations with P. falciparum infection. Four hundred four persons (aged 6 months–79 years, median 17 years) were enrolled in the study. The prevalence of P. falciparum parasitemia was 5.8% by RDT (95% CI: 3.55–9.33) and 16.9% by qPCR (95% CI: 13.09–21.71). The prevalence of anemia was 74.3% (95% CI: 69.04–78.85) as defined by the WHO criteria. All sampled houses were found to have open eaves; 99.5% of the surveyed population reported sleeping under a bednet (95% CI: 97.8–99.9). Although reported LLIN use is high, there remains an appreciable prevalence of malaria, suggesting that transmission is ongoing and further tools are required to reduce the burden of the disease.

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.

Accelerating the sustainable development goals through microbiology: some efforts and opportunities

Modernization has thrown humanity and other forms of life on our planet into a ditch of problems. Poverty, climate change, injustice and environmental degradation are a few of the shared global problems. The United Nations Sustainable Development Goals (SDGs) are the blueprint to achieve a better and more sustainable future for all. The SDGs are well structured to address the global challenges we face including poverty, inequalities, hunger, climate change, environmental degradation, peace and justice. Five years into the implementation, the SDGs have been driven mainly by international donors and 'professional' international development organizations. The world is left with 10 years to achieve these ambitious goals and targets. Various reviews show that little has been achieved overall, and the SDGs will not be a reality if a new strategy is not in place to bring inclusion. Microbiology, the scientific discipline of microbes, their effects and practical uses has insightful influence on our day-to-day living. We present how microbiology and microbiologists could increase the scorecard and accelerate these global goals. Microbiology has a direct link to achieving SDGs addressing food security, health and wellbeing, clean energy, environmental degradation and climate change. A non-classical growing relationship exists between microbiology and other SDGs such as peace, justice, gender equality, decent work and economic growth. The pledge of 'Leave No One Behind' will fast track progress and microbiology is in a better position to make this work.

Determinants of the persistence of malaria in Rwanda

Background

Malaria has a considerable impact on the health of the populations of developing countries; indeed, the entire population of Rwanda is at risk of contracting the disease. Although various interventions to control malaria have been implemented in Rwanda, the incidence of malaria has increased since 2012. There is an interest in understanding factors driving its persistence in Rwanda. This study aims at evaluating the effect of socio-economic and environmental factors, seasonality and the use of insecticide-treated mosquito nets (ITNs) on malaria persistence in Rwanda.

Methods

This study analysed data from the 2014–2015 Rwanda Demographic and Health Survey of 11,202 household’s members composed of children under the age of 5 and women aged between 15 and 49. Bivariate analysis was performed between the outcome and each covariate including wealth, altitude, education level, place of residence, and use of ITNs generating percentages. Chi square test was performed to compare malaria negatives and positives on each covariate. Significant variables were subjected to logistic regression analysis to evaluate factors that are significantly associated with malaria at P < 0.05. The analysis was performed in R x64 3.6 and QGIS3.6 was used to map geographical distribution of malaria cases.

Results

The lowest wealth category was associated with the incidence of malaria [AOR] = 1.54, 95% CI (1.78–2.03). Having a place of residence < 1700 m above sea level (asl) and non-use of ITNs were significantly associated with the incidence of malaria (adjusted odds ratio [AOR] = 2.93, 95% confidence interval [95% CI] 1.94–4.42 and [AOR] = 1.29, 95% C.I (1.03–1.60), respectively). Season and type of residence were not significantly associated with malaria prevalence while women had lower risk of contracting malaria than children.

Conclusion

Increased malaria prevalence was associated with lower income, non-compliance with bed-net usage and living below 1700 m of altitude. In addition to current malaria control strategies, potential interventions in individuals with lower income and areas at low altitudes should be taken into consideration when formulating malaria-control strategies, Also use of ITNs to control the spread of malaria should be emphasized.

Rainfall Trends and Malaria Occurrences in Limpopo Province, South Africa

This contribution aims to investigate the influence of monthly total rainfall variations on malaria transmission in the Limpopo Province. For this purpose, monthly total rainfall was interpolated from daily rainfall data from weather stations. Annual and seasonal trends, as well as cross-correlation analyses, were performed on time series of monthly total rainfall and monthly malaria cases in five districts of Limpopo Province for the period of 1998 to 2017. The time series analysis indicated that an average of 629.5 mm of rainfall was received over the period of study. The rainfall has an annual variation of about 0.46%. Rainfall amount varied within the five districts, with the northeastern part receiving more rainfall. Spearman's correlation analysis indicated that the total monthly rainfall with one to two months lagged effect is significant in malaria transmission across all the districts. The strongest correlation was noticed in Vhembe (r = 0.54; p-value = <0.001), Mopani (r = 0.53; p-value = <0.001), Waterberg (r = 0.40; p-value =< 0.001), Capricorn (r = 0.37; p-value = <0.001) and lowest in Sekhukhune (r = 0.36; p-value = <0.001). Seasonally, the results indicated that about 68% variation in malaria cases in summer-December, January, and February (DJF)-can be explained by spring-September, October, and November (SON)-rainfall in Vhembe district. Both annual and seasonal analyses indicated that there is variation in the effect of rainfall on malaria across the districts and it is seasonally dependent. Understanding the dynamics of climatic variables annually and seasonally is essential in providing answers to malaria transmission among other factors, particularly with respect to the abrupt spikes of the disease in the province.

LLIN Evaluation in Uganda Project (LLINEUP): factors associated with childhood parasitaemia and anaemia 3 years after a national long-lasting insecticidal net distribution campaign: a cross-sectional survey

Background

Recent reductions in malaria burden have been attributed largely to long-lasting insecticidal nets (LLINs). In March–June 2017, approximately 3 years after a national LLIN distribution campaign, a cross-sectional community survey was conducted to investigate factors associated with malaria parasitaemia and anaemia, in advance of Uganda’s 2017–2018 LLIN campaign.

Methods

Households from 104 clusters in 48 districts were randomly selected using two-staged cluster sampling; 50 households were enrolled per cluster. Eligible children aged 2–10 years had blood obtained for a thick blood smear and those aged 2–4 years had haemoglobin measured. Associations between outcomes and variables of interest were assessed using log-binomial regression with generalized estimating equations to adjust for household clustering.

Results

In total, 5196 households, 8834 children with blood smear results, and 3753 with haemoglobin results were included. Only 16% of children lived in households with adequate LLIN coverage. Overall, parasite prevalence was 26.0%, ranging from 8.0% in the South West to 53.1% in East Central. Limiting data to children 2–4 years of age, parasite prevalence was 21.4%, up from 16.9% in 2014–2015 following the national LLIN campaign. In a multivariate analysis, factors associated with parasitaemia included region (East-Central vs South-Western; adjusted prevalence ratio [aPR] 6.45, 95% CI 5.55–7.50; p < 0.001), older age (8–10 vs 2–3 years; aPR 1.57, 95% CI 1.43–1.72; p < 0.001), living in a poorer household (poorest vs least poor tercile; aPR 2.32, 95% CI 2.05–2.63; p < 0.001), one constructed of traditional materials (aPR 1.13, 95% CI 1.03–1.24; p = 0.008), or without adequate LLIN coverage (aPR 1.30, 95% CI 1.14–1.48; p < 0.001). Overall, the prevalence of anaemia (haemoglobin < 10 g/dL) was 15.1% and varied geographically. In a multivariate analysis, factors associated with anaemia included region, younger age, living in a traditional house, and parasitaemia, which was the strongest predictor (aPR 2.50, 95% CI 2.12–2.95; p < 0.001).

Conclusions

Three years after a national LLIN campaign, LLIN coverage was low and parasite prevalence had increased. Parasite prevalence varied widely across Uganda; older children, those living in poorer households, and those with inadequate LLIN coverage, were at highest risk of parasitaemia. LLINs may need to be distributed more frequently through mass campaigns or continuously through sustainable mechanisms. Targeting interventions to geographic areas and populations at highest risk should also be considered.

Household and maternal risk factors for malaria in pregnancy in a highly endemic area of Uganda: a prospective cohort study

Background

Malaria in pregnancy is a major public health challenge, but its risk factors remain poorly understood in some settings. This study assessed the association between household and maternal characteristics and malaria among pregnant women in a high transmission area of Uganda.

Methods

A nested prospective study was conducted between 6th September 2016 and 5th December 2017 in Busia district. 782 HIV uninfected women were enrolled in the parent study with convenience sampling. Socioeconomic and house construction data were collected via a household survey after enrolment. Homes were classified as modern (plaster or cement walls, metal or wooden roof and closed eaves) or traditional (all other homes). Maternal and household risk factors were evaluated for three outcomes: (1) malaria parasitaemia at enrolment, measured by thick blood smear and qPCR, (2) malaria parasitaemia during pregnancy following initiation of IPTp, measured by thick blood smear and qPCR and (3) placental malaria measured by histopathology.

Results

A total of 753 of 782 women were included in the analysis. Most women had no or primary education (75%) and lived in traditional houses (77%). At enrolment, microscopic or sub-microscopic parasitaemia was associated with house type (traditional versus modern: adjusted risk ratio (aRR) 1.29, 95% confidence intervals 1.15–1.45, p < 0.001), level of education (primary or no education versus O-level or beyond: aRR 1.13, 95% confidence interval 1.02–1.24, p = 0.02), and gravidity (primigravida versus multigravida: aRR 1.10, 95% confidence interval 1.02–1.18, p = 0.009). After initiation of IPTp, microscopic or sub-microscopic parasitaemia was associated with wealth index (poorest versus least poor: aRR 1.24, 95% CI 1.10–1.39, p < 0.001), house type (aRR 1.14, 95% CI 1.01–1.28, p = 0.03), education level (aRR 1.19, 95% CI 1.06–1.34, p = 0.002) and gravidity (aRR 1.32, 95% CI 1.20–1.45, p < 0.001). Placental malaria was associated with gravidity (aRR 2.87, 95% CI 2.39–3.45, p < 0.001), but not with household characteristics.

Conclusions

In an area of high malaria transmission, primigravid women and those belonging to the poorest households, living in traditional homes and with the least education had the greatest risk of malaria during pregnancy.

Challenges for the diagnosis and treatment of malaria in low transmission settings in San Lorenzo, Esmeraldas, Ecuador

BACKGROUND

Ecuador is on the verge of eliminating malaria according to the World Health Organization criteria. Nevertheless, active transmission foci still persist in the country, and these represent an important challenge for achieving the objectives set out. Diagnosis and treatment are a mainstay in the control and elimination of this disease. This study aimed to explore the barriers hindering the implementation of malaria diagnosis and treatment strategies in a focus of active transmission in the San Lorenzo canton, Ecuador.

METHODS

Using a convergent mixed methods design during 2017, the researchers assessed the physical and human resources of the services network at the primary level of care along with the quality assurance activities, patient access to healthcare services and perceptions regarding the care provided to patients with malaria.

RESULTS

The programme's administrative transition from the National Service of Vector-borne Diseases to the Ministry of Public Health is perceived from the interviewed participants to have weakened the diagnosis network established in recent years. A mean of 6.4 ± 0.88 months was found for anti-malarial medication shortage at the primary level of care. Likewise, there was high healthcare staff turnover (permanence, Me = 7 months; IQR = 5-16) and a deficit of general knowledge on the disease among the entirety of healthcare staff, as only 29% of physicians were aware of the correct first-line treatment for malaria by Plasmodium falciparum and Plasmodium vivax. It was evidenced that 95.7% of patients were hospitalized to receive anti-malarial treatment. Both patients and healthcare staff considered the area to be difficult to reach due to its geography and the presence of groups outside the law. They also identified the lack of personnel and microscopy posts in this border area as the main barrier.

CONCLUSION

The network of diagnostic services for malaria is weak in San Lorenzo, and socio-economic, political and historical factors hinder the implementation of the universal malaria elimination strategy based on diagnosis and treatment.

Maternal Employment and Child Survival During the Era of Sustainable Development Goals: Insights from Proportional Hazards Modelling of Nigeria Birth History Data

Background:

One of the targets for the third and fifth Sustainable Development Goals (SDGs) borders on children survival and women economic empowerment, respectively. A robust investigation of the relationship between maternal employment and childhood mortality will provide information useful for programs aimed at ensuring the complementarity of SDG 3 (healthy life for all) and SDG 5 (gender equality, girls and women empowerment).

Objective:

We addressed the following questions: (1) What is the independent relationship between maternal employment and infant (0–11 months) and child (12–59 months) mortality in Nigeria? (2) How does father’s occupation, type of residence, and geopolitical region modify the relationship?

Methods:

We retrospectively analysed cross-sectional data on weighted sample of 31,828 under-five children extracted from the birth history in the 2013 round of Nigeria Demographic and Health Survey, using Cox proportional hazards models. The outcomes of interest were infant (0–11 months) and child (12–59 months) mortality, and the main explanatory variables include maternal employment, involvement in decision making on work earnings, and father’s occupation. Other confounding variables were also controlled.

Findings:

Results showed that about two-third (68.7%) of under-five children had mothers who were working, with the majority engaged in self-employed occupations such as sales or small businesses, agriculture, and other manual labour. Infant mortality rate amongst children of employed mothers (65 per 1000 live births) was slightly less than the unemployed (70 per 1000 live births). A similar pattern was observed for child mortality. Hazards regression models revealed that the risk of both infant and child mortality was higher amongst unemployed women. Sales and agriculture/manual occupation constituted a higher risk for infant and child mortality. Analysis of interaction effects also revealed variations by father’s occupation, type of residence, and geopolitical region.

Conclusion:

The role of maternal employment in child survival is dynamic and depends on the type of occupation, family, and residential and regional context.

Rapid improvements to rural Ugandan housing and their association with malaria from intense to reduced transmission: a cohort study

BACKGROUND

Rapid population growth in Africa requires an urgent expansion and improvement of housing options. Improving housing presents a promising opportunity for malaria control by reducing indoor exposure to mosquitoes. We measured recent changes in house design in rural Uganda and evaluated their association with malaria in relation to a mass scale-up of control efforts.

METHODS

This analysis was part of a cohort study designed to compare temporal changes in malaria incidence from a cohort of children and adults with temporal changes in malaria test positivity rate from health facility surveillance. All children aged 6 months to 10 years (n=384) living in 107 households in Nagongera sub-country, Tororo, Uganda, were given long-lasting insecticide-treated nets and followed between Aug 19, 2011, and June 30, 2017. Repeat rounds of indoor residual spraying of insecticide were initiated on Dec 5, 2014. Socioeconomic data were collected at two timepoints (Sept 25-Oct 9, 2013 and June 21-July 11, 2016) and houses were classified as modern (cement, wood, or metal walls, tiled or metal roof, and closed eaves) or traditional (all other homes). Associations between house design and three outcomes were evaluated before and after the introduction of indoor residual spraying: human biting rate estimated monthly in each household using US Centers for Disease Control and Prevention light traps; parasite prevalence measured routinely by microscopy every 3 months before indoor residual spraying and monthly after indoor residual spraying; and malaria incidence measured by passive surveillance.

FINDINGS

The implementation of indoor residual spraying was associated with significant declines in human biting rate (33·5 vs 2·7 Anopheles per house per night after indoor residual spraying, p<0·0001), parasite prevalence (32·0% vs 14·0%, p<0·0001), and malaria incidence (3·0 vs 0·5 episodes per person-year at risk, p<0·0001). The prevalence of modern housing increased from 23·4% in 2013 to 45·4% in 2016 (p=0·001). Compared with traditional houses, modern houses were associated with a 48% reduction in human biting rate before indoor residual spraying (adjusted incidence rate ratio [aIRR] 0·52, 95% CI 0·36-0·73, p=0·0002), and a 73% reduction after indoor residual spraying (aIRR 0·27, 0·17-0·42, p<0·0001). Before indoor residual spraying, there was no association between house type and parasite prevalence, but after indoor residual spraying there was a 57% reduction in the odds of parasitaemia in modern houses compared with traditional houses, controlling for age, sex, and socioeconomic position (adjusted odds ratio 0·43, 95% CI 0·24-0·77, p=0·004). House type was not associated with malaria incidence before or after indoor residual spraying.

INTERPRETATION

House design improved rapidly in rural Uganda and was associated with additional reductions in mosquito density and parasite prevalence following the introduction of indoor residual spraying. Changes to house design in endemic Africa, including closing eaves and the replacement of traditional building materials, might help further the gains achieved with more widely accepted malaria control interventions.

FUNDING

US National Institutes of Health, Bill & Melinda Gates Foundation, and Medical Research Council UK.

Individual and household factors associated with incidences of village malaria in Xepon district, Savannakhet province, Lao PDR

Background

In the Lao PDR, the incidence of malaria greatly differs among villages even within a subdistrict, and the reasons for this difference are poorly understood. The objective of this study was to identify differences in villagers’ behavior and the household environment between villages with high incidences and those with low incidences of malaria in a rural district of the Lao PDR.

Methods

A case-control study was conducted in Xepon district, Savannakhet province. Case villages were defined as those with a high incidence (> 10 cases per 1000 population per year), and control villages were those with a low incidence (0–10 cases per 1000 population per year). Data were collected from 178 households in the six case villages and six control villages between December 2016 and January 2017. The data collection consisted of an interview survey with the heads of households and an observational survey in and around the house. Logistic regression was used to assess the association between the case-control status and individual-level behavioral factors and household-level environmental factors adjusted for socio-demographic and economic factors.

Results

Compared to the household members in the control villages, household members in the case villages were significantly more likely to work at night in the forest (adjusted odds ratio 1.95; 95% confidence interval 1.28 to 2.98) and more likely to sleep overnight in the forest (adjusted odds ratio 1.94; 95% confidence interval 1.13 to 3.33). Additionally, compared to the households in the control villages, households in the case villages were significantly more likely to have an open space on the house surface (adjusted odds ratio 3.64; 95% confidence interval 1.68 to 7.84).

Conclusions

There were significant differences in nighttime working and sleeping behaviors in the forest and the presence of an open space on the house surface in the case versus control villages. These differences can partly explain the difference in the incidences of malaria among the villages. The Lao National Malaria Control Program should recommend that villagers use personal protection when working and sleeping in the forest and to reduce any open space on the house surfaces.

Demographic, Socioeconomic, and Geographic Factors Leading to Severe Malaria and Delayed Care Seeking in Ugandan Children: A Case-Control Study

We studied associations between delayed care seeking, demographic, socioeconomic, and geographic factors and likelihood of severe malaria in Ugandan children. The study was based at Jinja Hospital, Uganda. We enrolled 325 severe malaria cases and 325 uncomplicated malaria controls matched by age and residence. Patient details, an itinerary of events in response to illness, household information, and location of participants' residences were captured. Conditional logistic regression was used to determine risk factors for severe malaria and delayed care seeking. Delayed care seeking (≥ 24 hours after fever onset; odds ratio [OR] 5.50; 95% confidence interval [CI] 2.70, 11.1), seeking care at a drug shop as the initial response to illness (OR 3.62; 95% CI 1.86, 7.03), and increasing distance from place of residence to the nearest health center (OR 1.45; 95% CI 1.17, 1.79) were independent risk factors for severe malaria. On subgroup analysis, delayed care seeking was a significant risk factor in children with severe malaria attributable to severe anemia (OR 15.6; 95% CI 3.02, 80.6), but not unconsciousness (OR 1.13; 95% CI 0.30, 4.28). Seeking care at a drug shop (OR 2.84; 95% CI 1.12, 7.21) and increasing distance to the nearest health center (OR 1.18; 95% CI 1.01, 1.37) were independent risk factors for delayed care seeking. Delayed care seeking and seeking care at a drug shop were risk factors for severe malaria. Seeking care at a drug shop was also a predictor of delayed care seeking. The role of drug shops in contributing to delayed care and risk of severe malaria requires further study.

Importance of risk factors associated with malaria for Sub-Saharan African children

To assess the importance of malaria risk factors for children in sub-Saharan African countries. 61,292 children of 16 countries from DHS and MIS surveys were included in analysis. A regression model with analyse of variance and plots of mean decrease accuracy and mean decrease Gini indices were performed. The most important risk factor was the country and it contributed 52.33 % to the variance of the model. Wealth status of the child's family was the first socio-economic factor which contributed more to the difference of malaria risk among African children. There was no geographic factor among the five most important variables. Quantity of precipitation was the sixth most important factor. Our study has the potential for driving control effort in the fight against malaria in the continent which represent the majority of global malaria cases. The study indicates that, when implementing health policies, community characteristics must be taken into account.

The contribution of malaria control interventions on spatio-temporal changes of parasitaemia risk in Uganda during 2009-2014

BACKGROUND

In Uganda, malaria vector control interventions and case management with Artemisinin Combination Therapies (ACTs) have been scaled up over the last few years as a result of increased funding. Data on parasitaemia prevalence among children less than 5 years old and coverage of interventions was collected during the first two Malaria Indicator Surveys (MIS) conducted in 2009 and 2014, respectively. In this study, we quantify the effects of control interventions on parasitaemia risk changes between the two MIS in a spatio-temporal analysis.

METHODS

Bayesian geostatistical and temporal models were fitted on the MIS data of 2009 and 2014. The models took into account geographical misalignment in the locations of the two surveys and adjusted for climatic changes and socio-economic differentials. Parasitaemia risk was predicted over a 2 × 2 km2 grid and the number of infected children less than 5 years old was estimated. Geostatistical variable selection was applied to identify the most important ITN coverage indicators. A spatially varying coefficient model was used to estimate intervention effects at sub-national level.

RESULTS

The coverage of Insecticide Treated Nets (ITNs) and ACTs more than doubled at country and sub-national levels during the period 2009-2014. The coverage of Indoor Residual Spraying (IRS) remained static at all levels. ITNs, IRS, and ACTs were associated with a reduction in parasitaemia odds of 19% (95% BCI: 18-29%), 78% (95% BCI: 67-84%), and 34% (95% BCI: 28-66%), respectively. Intervention effects varied with region. Higher socio-economic status and living in urban areas were associated with parasitaemia odds reduction of 46% (95% BCI: 0.51-0.57) and 57% (95% BCI: 0.40-0.53), respectively. The probability of parasitaemia risk decline in the country was 85% and varied from 70% in the North-East region to 100% in Kampala region. The estimated number of children infected with malaria declined from 2,480,373 in 2009 to 825,636 in 2014.

CONCLUSIONS

Interventions have had a strong effect on the decline of parasitaemia risk in Uganda during 2009-2014, albeit with varying magnitude in the regions. This success should be sustained by optimizing ITN coverage to achieve universal coverage.

Eave tubes for malaria control in Africa: a modelling assessment of potential impact on transmission

BACKGROUND

Novel interventions for malaria control are necessary in the face of problems such as increasing insecticide resistance and residual malaria transmission. One way to assess performance prior to deployment in the field is through mathematical modelling. Modelled here are a range of potential outcomes for eave tubes, a novel mosquito control tool combining house screening and targeted use of insecticides to provide both physical protection and turn the house into a lethal mosquito killing device.

METHODS

The effect of eave tubes was modelled by estimating the reduction of infectious mosquito bites relative to no intervention (a transmission metric defined as relative transmission potential, RTP). The model was used to assess how RTP varied with coverage when eave tubes were used as a stand-alone intervention, or in combination with either bed nets (LLINs) or indoor residual spraying (IRS).

RESULTS

The model indicated the impact of eave tubes on transmission increases non-linearly as coverage increases, suggesting a community level benefit. For example, based on realistic assumptions, just 30 % coverage resulted in around 70 % reduction in overall RTP (i.e. there was a benefit for those houses without eave tubes). Increasing coverage to around 70 % reduced overall RTP by >90 %. Eave tubes exhibited some redundancy with existing interventions, such that combining interventions within properties did not give reductions in RTP equal to the sum of those provided by deploying each intervention singly. However, combining eave tubes and either LLINs or IRS could be extremely effective if the technologies were deployed in a non-overlapping way.

CONCLUSION

Using predictive models to assess the benefit of new technologies has great value, and is especially pertinent prior to conducting expensive, large scale, randomized controlled trials. The current modelling study indicates eave tubes have considerable potential to impact malaria transmission if deployed at scale and can be used effectively with existing tools, especially if they are combined strategically with, for example, IRS and eave tubes targeting different houses.