Malaria determining risk factors at the household level in two rural villages of mainland Equatorial Guinea

A prospective cohort study linking migration, climate, and malaria risk in the Peruvian Amazon

Migration is an important risk factor for malaria transmission for malaria transmission, creating networks that connect Plasmodium between communities. This study aims to understand the timing of why people in the Peruvian Amazon migrated and how characteristics of these migrants are associated with malaria risk. A cohort of 2,202 participants was followed for three years (July 2006 - October 2009), with thrice-weekly active surveillance to record infection and recent travel, which included travel destination(s) and duration away. Migration occurred more frequently in the dry season, but the 7-day rolling mean (7DRM) streamflow was positively correlated with migration events (OR 1.25 (95% CI: 1.138, 1.368)). High-frequency and low-frequency migrant populations reported 9.7 (IRR 7.59 (95% CI:.381, 13.160)) and 4.1 (IRR 2.89 (95% CI: 1.636, 5.099)) times more P. vivax cases than those considered non-migrants and 30.7 (IRR 32.42 (95% CI: 7.977, 131.765)) and 7.4 (IRR 7.44 (95% CI: 1.783, 31.066)) times more P. falciparum cases, respectively. High-frequency migrants employed in manual labour within their community were at 2.45 (95% CI: 1.113, 5.416) times higher risk than non-employed low-frequency migrants. This study confirms the importance of migration for malaria risk as well as factors increasing risk among the migratory community, including, sex, occupation, and educational status.

Complete sources of cluster variation on the risk of under-five malaria in Uganda: a multilevel-weighted mixed effects logistic regression model approach

BACKGROUND

Malaria, a major cause of mortality worldwide is linked to a web of determinants ranging from individual to contextual factors. This calls for examining the magnitude of the effect of clustering within malaria data. Regrettably, researchers usually ignore cluster variation on the risk of malaria and also apply final survey weights in multilevel modelling instead of multilevel weights. This most likely produces biased estimates, misleads inference and lowers study power. The objective of this study was to determine the complete sources of cluster variation on the risk of under-five malaria and risk factors associated with under-five malaria in Uganda.

METHODS

This study applied a multilevel-weighted mixed effects logistic regression model to account for both individual and contextual factors.

RESULTS

Every additional year in a child's age was positively associated with malaria infection (AOR = 1.42; 95% CI 1.33-1.52). Children whose mothers had at least a secondary school education were less likely to suffer from malaria infection (AOR = 0.53; 95% CI 0.30-0.95) as well as those who dwelled in households in the two highest wealth quintiles (AOR = 0.42; 95% CI 0.27-0.64). An increase in altitude by 1 m was negatively associated with malaria infection (AOR = 0.98; 95% CI 0.97-0.99). About 77% of the total variation in the positive testing for malaria was attributable to differences between enumeration areas (ICC = 0.77; p < 0.001).

CONCLUSIONS

Interventions towards reducing the burden of under-five malaria should be prioritized to improve individual-level characteristics compared to household-level features. Enumeration area (EA) specific interventions may be more effective compared to household specific interventions.

Magnitude of malaria and associated factors among febrile adults in Siraro District Public Health facilities, West Arsi Zone, Oromia, Ethiopia 2022: a facility-based cross-sectional study

BACKGROUND

Despite significant efforts made to control malaria in Ethiopia, the disease remains one of the top public health problems in the country. Baseline malaria prevalence and associated factor at high malaria area is important to guide malaria control interventions, there was paucity of information regarding the study area. Therefore, the aim of this study was to determine prevalence of malaria and associated factors among febrile adults in Siraro district health facilities, West Arsi Zone, Oromia, Ethiopia.

METHODS

Institution-based cross-sectional study was conducted among 317 febrile adult patients at Siraro district health facilities. Structured pre-tested questionnaires were used to collect data. Epi-data version 3.1 and SPSS version 23 were used for data entry and analysis respectively. In order to identify factors associated with malaria infection bivariable and multivariable binary logistic regression analysis was employed, The Adjusted Odds Ratio (AOR) with a 95% confidence interval (CI) and p-value of < 0.05 was computed to show the strength of the association.

RESULTS

The overall prevalence of malaria at the study area was 130 (41.0%) [(95% CI 35.3-46.7)]. Occupation (being farmer) [(AOR = 6.05; 95% CI 1.38, 26.49)], having poor knowledge on malaria transmission [(AOR = 2.95 95%; CI 1.48-5.88)], house with wood wall [(AOR = 2.71; 95% CI 1.34-5.49)], and number of windows (≥ 3) in the house [(AOR = 6.82; 95% CI 1.05, 44.40)] were identified to be significantly associated with magnitude of malaria in the study area.

CONCLUSION

The prevalence of malaria at the study area was high as compared with the national wide figures. Being farmer, having poor knowledge on malaria transmission, and housing condition (house with wood wall and houses with three and above windows) were found to be significantly associated with malaria infection in the study area. Therefore, there has to be an emphasis on addressing the factors by providing sustainable health education for the communities to improve their housing condition and knowledge of community on the way of malaria prevention.

Effects of Age, Gender and Soil-Transmitted Helminth Infection on Prevalence of Plasmodium Infection among Population Living in Bata District, Equatorial Guinea

Introduction: Malaria and soil-transmitted helminth (STH) co-infection is an important parasitic infection affecting populations in co-endemic countries including Equatorial Guinea. To date, the health impact of STH and malaria co-infection is inconclusive. The current study aimed to report the malaria and STH infection epidemiology in the continental region of Equatorial Guinea. Methods: We performed a cross-sectional study between October 2020 and January 2021 in the Bata district of Equatorial Guinea. Participants aged 1–9 years, 10–17 years and above 18 were recruited. Fresh venous blood was collected for malaria testing via mRDTs and light microscopy. Stool specimens were collected, and the Kato–Katz technique was used to detect the presence of Ascaris lumbricoides, Trichuris trichiura, hookworm spp. and intestinal Schistosoma eggs. Results: A total of 402 participants were included in this study. An amount of 44.3% of them lived in urban areas, and only 51.9% of them reported having bed nets. Malaria infections were detected in 34.8% of the participants, while 50% of malaria infections were reported in children aged 10–17 years. Females had a lower prevalence of malaria (28.8%) compared with males (41.7%). Children of 1–9 years carried more gametocytes compared with other age groups. An amount of 49.3% of the participants infected with T. trichiura had malaria parasites compared with those infected with A. lumbricoides (39.6%) or both (46.8%). Conclusions: The overlapping problem of STH and malaria is neglected in Bata. The current study forces the government and other stakeholders involved in the fight against malaria and STH to consider a combined control program strategy for both parasitic infections in Equatorial Guinea.

Clinical malaria incidence and health seeking pattern in geographically heterogeneous landscape of western Kenya

Background

Malaria remains a public health problem in Kenya despite sustained interventions deployed by the government. One of the major impediments to effective malaria control is a lack of accurate diagnosis and effective treatment. This study was conducted to assess clinical malaria incidence and treatment seeking profiles of febrile cases in western Kenya.

Methods

Active case detection of malaria was carried out in three eco-epidemiologically distinct zones topologically characterized as lakeshore, hillside, and highland plateau in Kisumu County, western Kenya, from March 2020 to March 2021. Community Health Volunteers (CHVs) conducted biweekly visits to residents in their households to interview and examine for febrile illness. A febrile case was defined as an individual having fever (axillary temperature ≥ 37.5 °C) during examination or complaints of fever and other nonspecific malaria related symptoms 1–2 days before examination. Prior to the biweekly malaria testing by the CHVs, the participants' treatment seeking methods were based on their behaviors in response to febrile illness. In suspected malaria cases, finger-prick blood samples were taken and tested for malaria parasites with ultra-sensitive Alere^® malaria rapid diagnostic tests (RDT) and subjected to real-time polymerase chain reaction (RT-PCR) for quality control examination.

Results

Of the total 5838 residents interviewed, 2205 residents had high temperature or reported febrile illness in the previous two days before the visit. Clinical malaria incidence (cases/1000people/month) was highest in the lakeshore zone (24.3), followed by the hillside (18.7) and the highland plateau zone (10.3). Clinical malaria incidence showed significant difference across gender (χ² = 7.57; df = 2, p = 0.0227) and age group (χ² = 58.34; df = 4, p < 0.0001). Treatment seeking patterns of malaria febrile cases showed significant difference with doing nothing (48.7%) and purchasing antimalarials from drug shops (38.1%) being the most common health-seeking pattern among the 2205 febrile residents (χ² = 21.875; df = 4, p < 0.0001). Caregivers of 802 school-aged children aged 5–14 years with fever primarily sought treatment from drug shops (28.9%) and public hospitals (14.0%), with significant lower proportions of children receiving treatment from traditional medication (2.9%) and private hospital (4.4%) (p < 0.0001). There was no significant difference in care givers' treatment seeking patterns for feverish children under the age of five (p = 0.086). Residents with clinical malaria cases in the lakeshore and hillside zones sought treatment primarily from public hospitals (61.9%, 60/97) traditional medication (51.1%, 23/45) respectively (p < 0.0001). However, there was no significant difference in the treatment seeking patterns of highland plateau residents with clinical malaria (p = 0.431).The main factors associated with the decision to seek treatment were the travel distance to the health facility, the severity of the disease, confidence in the treatment, and affordability.

Conclusion

Clinical malaria incidence remains highest in the Lakeshore (24.3cases/1000 people/month) despite high LLINs coverage (90%). The travel distance to the health facility, severity of disease and affordability were mainly associated with 80% of residents either self-medicating or doing nothing to alleviate their illness. The findings of this study suggest that the Ministry of Health should strengthen community case management of malaria by providing supportive supervision of community health volunteers to advocate for community awareness, early diagnosis, and treatment of malaria.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07757-w.

Multilevel logistic regression modelling to quantify variation in malaria prevalence in Ethiopia

Background

Ethiopia has low malaria prevalence compared to most other malaria-endemic countries in Africa. However, malaria is still a major public health problem in the country. The binary logistic regression model has been widely used to analyse malaria indicator survey (MIS) data. However, most MIS have a hierarchical structure which may result in dependent data. Since this model assumes that conditional on the covariates the malaria statuses of individuals are independent, it ignores potential intra-cluster correlation among observations within a cluster and may generate biased analysis results and conclusions. Therefore, the aim of this study was to quantify the variation in the prevalence of malaria between sample enumeration areas (SEAs) or clusters, the effects of cluster characteristics on the prevalence of malaria using the intra-class correlation coefficient as well as to identify significant factors that affect the prevalence of malaria using the multilevel logistic regression modelling in three major regions of Ethiopia, namely Amhara, Oromia and Southern Nations, Nationalities and Peoples’ (SNNP).

Methods

Dataset for three regional states extracted from the 2011 Ethiopian National Malaria Indicator Surveys (EMIS) national representative samples was used in this study. It contains 9272 sample individuals selected from these regions. Various multilevel models with random sample SEA effects were applied taking into account the survey design weights. These weights are scaled to address unequal probabilities of selection within clusters. The spatial clustering of malaria prevalence was assessed applying Getis-Ord statistic to best linear unbiased prediction values of model random effects.

Results

About 53.82 and 28.72 per cents of the sampled households in the study regions had no mosquito net and sprayed at least once within the last 12 months, respectively. The results of this study indicate that age, gender, household had mosquito nets, the dwelling has windows, source of drinking water, the two SEA-level variables, i.e. region and median altitude, were significantly related to the prevalence of malaria. After adjusting for these seven variables, about 45% of the residual variation in the prevalence of malaria in the study regions was due to systematic differences between SEAs, while the remaining 55% was due to unmeasured differences between persons or households. The estimated MOR, i.e. the unexplained SEA heterogeneity, was 4.784. This result suggests that there is high variation between SEAs in the prevalence of malaria. In addition, the 80% interval odds ratios (IORs) related to SEA-level variables contain one suggesting that the SEA variability is large in comparison with the effect of each of the variable.

Conclusions

The multilevel logistic regression with random effects model used in this paper identified five individual / household and two SEA-level risk factors of malaria infection. Therefore, the public health policy makers should pay attentions to those significant factors, such as improving the availability of pure drinking water. Further, the findings of spatial clustering provide information to health policymakers to plan geographically targeted interventions to control malaria transmission.

Influence of landscape heterogeneity on entomological and parasitological indices of malaria in Kisumu, Western Kenya

Background

Identification and characterization of larval habitats, documentation of Anopheles spp. composition and abundance, and Plasmodium spp. infection burden are critical components of integrated vector management. The present study aimed to investigate the effect of landscape heterogeneity on entomological and parasitological indices of malaria in western Kenya.

Methods

A cross-sectional entomological and parasitological survey was conducted along an altitudinal transect in three eco-epidemiological zones: lakeshore along the lakeside, hillside, and highland plateau during the wet and dry seasons in 2020 in Kisumu County, Kenya. Larval habitats for Anopheles mosquitoes were identified and characterized. Adult mosquitoes were sampled using pyrethrum spray catches (PSC). Finger prick blood samples were taken from residents and examined for malaria parasites by real-time PCR (RT-PCR).

Results

Increased risk of Plasmodium falciparum infection was associated with residency in the lakeshore zone, school-age children, rainy season, and no ITNs (χ² = 41.201, df = 9, P < 0.0001). Similarly, lakeshore zone and the rainy season significantly increased Anopheles spp. abundance. However, house structures such as wall type and whether the eave spaces were closed or open, as well as the use of ITNs, did not affect Anopheles spp. densities in the homes (χ² = 38.695, df = 7, P < 0.0001). Anopheles funestus (41.8%) and An. arabiensis (29.1%) were the most abundant vectors in all zones. Sporozoite prevalence was 5.6% and 3.2% in the two species respectively. The lakeshore zone had the highest sporozoite prevalence (4.4%, 7/160) and inoculation rates (135.2 infective bites/person/year). High larval densities were significantly associated with lakeshore zone and hillside zones, animal hoof prints and tire truck larval habitats, wetland and pasture land, and the wet season. The larval habitat types differed significantly across the landscape zones and seasonality (χ² = 1453.044, df = 298, P < 0.0001).

Conclusion

The empirical evidence on the impact of landscape heterogeneity and seasonality on vector densities, parasite transmission, and Plasmodium infections in humans emphasizes the importance of tailoring specific adaptive environmental management interventions to specific landscape attributes to have a significant impact on transmission reduction.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05447-9.

Molecular screening reveals non-uniform malaria transmission in western Kenya and absence of Rickettsia africae and selected arboviruses in hospital patients

Background

In sub-Saharan Africa, malaria is the common diagnosis for febrile illness and related clinical features, resulting in the under-diagnosis of other aetiologies, such as arboviruses and Rickettsia. While these may not be significant causes of mortality in malaria-endemic areas, they affect the daily life and performance of affected individuals. It is, therefore, important to have a clear picture of these other aetiologies to institute correct diagnoses at hospitals and improve patient outcomes.

Methods

Blood samples were collected from patients with fever and other clinical features associated with febrile illness at selected hospitals in the malaria-endemic counties of Busia, Bungoma, and Kakamega, and screened for Crimean-Congo haemorrhagic fever, Sindbis, dengue and chikungunya viruses, Rickettsia africae, and Plasmodium spp. using high-throughput real-time PCR techniques. A logistic regression was performed on the results to explore the effect of demographic and socio-economic independent variables on malaria infection.

Results

A total of 336 blood samples collected from hospital patients between January 2018 and February 2019 were screened, of which 17.6% (59/336) were positive for Plasmodium falciparum and 1.5% (5/336) for Plasmodium malariae. Two patients had dual P. falciparum/P. malariae infections. The most common clinical features reported by the patients who tested positive for malaria were fever and headache. None of the patients were positive for the arboviruses of interest or R. africae. Patients living in Busia (OR 5.2; 95% CI 2.46–11.79; p < 0.001) and Bungoma counties (OR 2.7; 95% CI 1.27–6.16; p = 0.013) had higher odds of being infected with malaria, compared to those living in Kakamega County.

Conclusions

The reported malaria prevalence is in line with previous studies. The absence of arboviral and R. africae cases in this study may have been due to the limited number of samples screened, low-level circulation of arboviruses during inter-epidemic periods, and/or the use of PCR alone as a detection method. Other sero-surveys confirming their circulation in the area indicate that further investigations are warranted.

Cooking outdoors or with cleaner fuels does not increase malarial risk in children under 5 years: a cross-sectional study of 17 sub-Saharan African countries

Background

Smoke from solid biomass cooking is often stated to reduce household mosquito levels and, therefore, malarial transmission. However, household air pollution (HAP) from solid biomass cooking is estimated to be responsible for 1.67 times more deaths in children aged under 5 years compared to malaria globally. This cross-sectional study investigates the association between malaria and (i) cleaner fuel usage; (ii) wood compared to charcoal fuel; and, (iii) household cooking location, among children aged under 5 years in sub-Saharan Africa (SSA).

Methods

Population-based data was obtained from Demographic and Health Surveys (DHS) for 85,263 children within 17 malaria-endemic sub-Saharan countries who were who were tested for malaria with a malarial rapid diagnostic test (RDT) or microscopy. To assess the independent association between malarial diagnosis (positive, negative), fuel type and cooking location (outdoor, indoor, attached to house), multivariable logistic regression was used, controlling for individual, household and contextual confounding factors.

Results

Household use of solid biomass fuels and kerosene cooking fuels was associated with a 57% increase in the odds ratio of malarial infection after adjusting for confounding factors (RDT adjusted odds ratio (AOR):1.57 [1.30–1.91]; Microscopy AOR: 1.58 [1.23–2.04]) compared to cooking with cleaner fuels. A similar effect was observed when comparing wood to charcoal among solid biomass fuel users (RDT AOR: 1.77 [1.54–2.04]; Microscopy AOR: 1.21 [1.08–1.37]). Cooking in a separate building was associated with a 26% reduction in the odds of malarial infection (RDT AOR: 0.74 [0.66–0.83]; Microscopy AOR: 0.75 [0.67–0.84]) compared to indoor cooking; however no association was observed with outdoor cooking. Similar effects were observed within a sub-analysis of malarial mesoendemic areas only.

Conclusion

Cleaner fuels and outdoor cooking practices associated with reduced smoke exposure were not observed to have an adverse effect upon malarial infection among children under 5 years in SSA. Further mixed-methods research will be required to further strengthen the evidence base concerning this risk paradigm and to support appropriate public health messaging in this context.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04152-3.

Health care provider practices in diagnosis and treatment of malaria in rural communities in Kisumu County, Kenya

BACKGROUND

Accurate malaria diagnosis and appropriate treatment at local health facilities are critical to reducing morbidity and human reservoir of infectious gametocytes. The current study assessed the accuracy of malaria diagnosis and treatment practices in three health care facilities in rural western Kenya.

METHODS

The accuracy of malaria detection and treatment recommended compliance was monitored in two public and one private hospital from November 2019 through March 2020. Blood smears from febrile patients were examined by hospital laboratory technicians and re-examined by an expert microscopists thereafter subjected to real-time polymerase chain reaction (RT-PCR) for quality assurance. In addition, blood smears from patients diagnosed with malaria rapid diagnostic tests (RDT) and presumptively treated with anti-malarial were re-examined by an expert microscopist.

RESULTS

A total of 1131 febrile outpatients were assessed for slide positivity (936), RDT (126) and presumptive diagnosis (69). The overall positivity rate for Plasmodium falciparum was 28% (257/936). The odds of slide positivity was higher in public hospitals, 30% (186/624, OR:1.44, 95% CI = 1.05-1.98, p < 0.05) than the private hospital 23% (71/312, OR:0.69, 95% CI = 0.51-0.95, p < 0.05). Anti-malarial treatment was dispensed more at public hospitals (95.2%, 177/186) than the private hospital (78.9%, 56/71, p < 0.0001). Inappropriate anti-malarial treatment, i.e. artemether-lumefantrine given to blood smear negative patients was higher at public hospitals (14.6%, 64/438) than the private hospital (7.1%, 17/241) (p = 0.004). RDT was the most sensitive (73.8%, 95% CI = 39.5-57.4) and specific (89.2%, 95% CI = 78.5-95.2) followed by hospital microscopy (sensitivity 47.6%, 95% CI = 38.2-57.1) and specificity (86.7%, 95% CI = 80.8-91.0). Presumptive diagnosis had the lowest sensitivity (25.7%, 95% CI = 13.1-43.6) and specificity (75.0%, 95% CI = 50.6-90.4). RDT had the highest non-treatment of negatives [98.3% (57/58)] while hospital microscopy had the lowest [77.3% (116/150)]. Health facilities misdiagnosis was at 27.9% (77/276). PCR confirmed 5.2% (4/23) of the 77 misdiagnosed cases as false positive and 68.5% (37/54) as false negative.

CONCLUSIONS

The disparity in malaria diagnosis at health facilities with many slide positives reported as negatives and high presumptive treatment of slide negative cases, necessitates augmenting microscopic with RDTs and calls for Ministry of Health strengthening supportive infrastructure to be in compliance with treatment guidelines of Test, Treat, and Track to improve malaria case management.

High Prevalence of Asymptomatic Malarial Anemia and Association with Early Conversion from Asymptomatic to Symptomatic Infection in a Plasmodium falciparum Hyperendemic Setting in Cameroon

Asymptomatic malarial parasitemia is highly prevalent in Plasmodium falciparum endemic areas and often associated with increased prevalence of mild to moderate anemia. The aim of this study was to assess the prevalence of anemia during asymptomatic malaria parasitemia and its interplay with persistent infection in highly exposed individuals. A household-based longitudinal survey was undertaken in a malaria hyperendemic area in Cameroon using multiplex nested polymerase chain reaction to detect plasmodial infections. Residents with P. falciparum asymptomatic parasitemia were monitored over a 3-week period with the aid of structured questionnaires and weekly measurements of axillary temperatures. Of the 353 individuals included (median age: 26 years, range 2-86 years, male/female sex ratio 0.9), 328 (92.9%) were positive for malaria parasitemia of whom 266 (81.1%) were asymptomatic carriers. The prevalence of anemia in the study population was 38.6%, of which 69.2% were asymptomatic. Multivariate analyses identified high parasitemia (> 327 parasites/µL) and female gender as associated risk factors of asymptomatic malarial anemia in the population. Furthermore, risk analyses revealed female gender and anemia at the time of enrolment as key predictors of early development of febrile illness (< 3 weeks post enrolment) among the asymptomatic individuals. Together, the data reveal an extremely high prevalence of asymptomatic malaria parasitemia and anemia in the study area, unveiling for the first time the association of asymptomatic malarial anemia with early clinical conversion from asymptomatic to symptomatic infection. Furthermore, these findings underscore the negative impact of asymptomatic malaria parasitemia on individual health, necessitating the development of appropriate control and preventive measures.

Malaria infection and anemia status in under-five children from Southern Tanzania where seasonal malaria chemoprevention is being implemented

Background

Malaria and anemia remain major public health challenges in Tanzania. Household socioeconomic factors are known to influence these conditions. However, it is not clear how these factors influence malaria transmission and anemia in Masasi and Nanyumbu Districts. This study presents findings on malaria and anemia situation in under-five children and its influencing socioeconomic factors in Masasi and Nanyumbu Districts, surveyed as part of an ongoing seasonal malaria chemoprevention operational study.

Methods

A community-based cross-sectional survey was conducted between August and September 2020. Finger-prick blood samples collected from children aged 3–59 months were used to test for malaria infection using malaria rapid diagnostic test (mRDT), thick smears for determination of asexual and sexual parasitemia, and thin smear for parasite speciation. Hemoglobin concentration was measured using a HemoCue spectrophotometer. A structured questionnaire was used to collect household socioeconomic information from parents/caregivers of screened children. The prevalence of malaria was the primary outcome. Chi-square tests, t-tests, and logistic regression models were used appropriately.

Results

Overall mRDT-based malaria prevalence was 15.9% (373/2340), and was significantly higher in Nanyumbu (23.7% (167/705) than Masasi District (12.6% (206/1635), p<0.001. Location (Nanyumbu), no formal education, household number of people, household number of under-fives, not having a bed net, thatched roof, open/partially open eave, sand/soil floor, and low socioeconomic status were major risks for malaria infection. Some 53.9% (1196/2218) children had anemia, and the majority were in Nanyumbu (63.5% (458/705), p<0.001. Location (Nanyumbu), mRDT positive, not owning a bed net, not sleeping under bed net, open/partially open eave, thatched window, sex of the child, and age of the child were major risk factors for anemia.

Conclusion

Prevalence of malaria and anemia was high and was strongly associated with household socioeconomic factors. Improving household socioeconomic status is expected to reduce the prevalence of the conditions in the area.

Individual, household and neighborhood risk factors for malaria in the Democratic Republic of the Congo support new approaches to programmatic intervention

BACKGROUND

The Democratic Republic of the Congo (DRC) remains one of the countries most impacted by malaria despite decades of control efforts, including multiple mass insecticide treated net (ITN) distribution campaigns. The multi-scalar and complex nature of malaria necessitates an understanding of malaria risk factors over time and at multiple levels (e.g., individual, household, community). Surveillance of households in both rural and urban settings over time, coupled with detailed behavioral and geographic data, enables the detection of seasonal trends in malaria prevalence and malaria-associated behaviors as well as the assessment of how the local environments within and surrounding an individual's household impact malaria outcomes.

METHODS

Participants from seven sites in Kinshasa Province, DRC were followed for over two years. Demographic, behavioral, and spatial information was gathered from enrolled households. Malaria was assessed using both rapid diagnostic tests (RDT) and polymerase chain reaction (PCR) and seasonal trends were assessed. Hierarchical regression modeling tested associations between behavioral and environmental factors and positive RDT and PCR outcomes at individual, household and neighborhood scales.

RESULTS

Among 1591 enrolled participants, malaria prevalence did not consistently vary seasonally across the sites but did vary by age and ITN usage. Malaria was highest and ITN usage lowest in children ages 6-15 years across study visits and seasons. Having another member of the household test positive for malaria significantly increased the risk of an individual having malaria [RDT: OR = 4.158 (2.86-6.05); PCR: OR = 3.37 (2.41-4.71)], as did higher malaria prevalence in the 250 m neighborhood around the household [RDT: OR = 2.711 (1.42-5.17); PCR: OR = 4.056 (2.3-7.16)]. Presence of water within close proximity to the household was also associated with malaria outcomes.

CONCLUSIONS

Taken together, these findings suggest that targeting non-traditional age groups, children >5 years old and teenagers, and deploying household- and neighborhood-focused interventions may be effective strategies for improving malaria outcomes in high-burden countries like the DRC.

Malaria among febrile neonates attending the neonatology unit of the Bamenda regional hospital

Malaria remains the leading cause of infant’s mortality in malaria endemic countries like Cameroon. Due to the presence of passively acquired maternal antibodies, malaria in neonates was thought to be scarce. Consequently routine malaria checks are mostly not considered for febrile neonates. Nonetheless findings from malaria endemic areas have proven that malaria in neonates is not uncommon. This study is therefore designed to evaluate malaria among febrile neonates attending the neonatology unit of the Bamenda Regional Hospital. A structured questionnaire and laboratory diagnostic test methods were used for data collection. Maternal sociodemographic data and malaria predisposing factors for neonates with and without malaria were determined using sums and percentages of mean. Regression analysis was used to determine the effects of age of mother, parity, mother’s educational level, sex of neonate and malaria predisposing factors on malaria parasitaemia. Chi-square (and Fisher’s exact) test was used to calculate sensitivity (%), specificity (%), predictive values (%), likelihood ratios, odd ratios, relative risk and attributable risk. A total of 189 neonates were included in the study out of which 33 (17.46%) tested malaria positive. 54.55% (18/33) of the malaria positive neonates were˃ 3 – 4 weeks old, while only 09.09% (03/33) were within 0 – 1 week of age. Neonates who presented with both signs of “fever + refusal to feed” were found to be most likely (P = 0.0188) to test malaria positive. Based on these findings routine malaria test is recommended especially for all neonates who presents with both signs of “fever + refusal to feed”, in malaria endemic regions.

Variation of preventive practices and its association with malaria infection in eastern Indonesia: Findings from community-based survey

Background

Geographical variation may likely influence the effectiveness of prevention efforts for malaria across Indonesia, in addition to factors at the individual level, household level, and contextual factors. This study aimed to describe preventive practices at individual and a household levels applied by rural communities in five provinces in eastern Indonesia and its association with the incidence of malaria among adult (≥15 years) populations.

Methods

This study analyzed a subset of data of nationally representative community-based survey 2018 Riset Kesehatan Dasar (Riskesdas). Data for socio-demographic (age, gender, education and occupation) and preventive behaviors (use of mosquito bed nets while slept, insecticide-treated mosquito nets (ITNs), mosquito repellent, mosquito electric rackets, mosquito coil/electric anti-mosquito mats, and mosquito window screen) were collected. Data were analyzed using bivariate and multivariable logistic regression model.

Results

Total of 56,159 respondents (n = 23,070 households) living in rural areas in Maluku (n = 8044), North Maluku (n = 7356), East Nusa Tenggara (n = 23,254), West Papua (n = 5759) and Papua (n = 11,746) were included in the study. In the multivariable models, using a bed net while slept likely reduced the odds of self-reported malaria among Maluku participants. Reduced odds ratios of self-reported malaria were identified in those participants who used ITNs (North Maluku, ENT, Papua), repellent (Maluku, West Papua, Papua), anti-mosquito racket (ENT), coil (Maluku, North Maluku, Papua) and window screen (West Papua, Papua).

Conclusion

Our study concluded that the protective effects of preventive practices were varied among localities, suggesting the need for specific intervention programs.

Trends in Molecular Markers Associated with Resistance to Sulfadoxine-Pyrimethamine (SP) Among Plasmodium falciparum Isolates on Bioko Island, Equatorial Guinea: 2011-2017

PURPOSE

Antimalarial drug resistance is one of the major challenges in global efforts to control and eliminate malaria. In 2006, sulfadoxine-pyrimethamine (SP) replaced with artemisinin-based combination therapy (ACT) on Bioko Island, Equatorial Guinea, in response to increasing SP resistance, which is associated with mutations in the dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes.

PATIENTS AND METHODS

To evaluate the trend of molecular markers associated with SP resistance on Bioko Island from 2011 to 2017, 179 samples collected during active case detection were analysed by PCR and DNA sequencing.

RESULTS

Pfdhfr and Pfdhps gene sequences were obtained for 90.5% (162/179) and 77.1% (138/179) of the samples, respectively. For Pfdhfr, 97.5% (158/162), 95.7% (155/162) and 98.1% (159/162) of the samples contained N51I, C59R and S108N mutant alleles, respectively. And Pfdhps S436A, A437G, K540E, A581G, and A613S mutations were observed in 25.4% (35/138), 88.4% (122/138), 5.1% (7/138), 1.4% (2/138), and 7.2% (10/138) of the samples, respectively. Two classes of previously described Pfdhfr-Pfdhps haplotypes associated with SP resistance and their frequencies were identified: partial (IRNI-SGKAA, 59.4%) and full (IRNI-SGEAA, 5.5%) resistance. Although no significant difference was observed in different time periods (p>0.05), our study confirmed a slowly increasing trend of the frequencies of these SP-resistance markers in Bioko parasites over the 7 years investigated.

CONCLUSION

The findings reveal the general existence of SP-resistance markers on Bioko Island even after the replacement of SP as a first-line treatment for uncomplicated malaria. Continuous molecular monitoring and additional control efforts in the region are urgently needed.

High prevalence of Pfdhfr-Pfdhps quadruple mutations associated with sulfadoxine-pyrimethamine resistance in Plasmodium falciparum isolates from Bioko Island, Equatorial Guinea

BACKGROUND

Sulfadoxine-pyrimethamine (SP) is recommended for intermittent preventive treatment of malaria in Africa. However, increasing SP resistance (SPR) affects the therapeutic efficacy of the SP. As molecular markers, Pfdhfr (dihydrofolate reductase) and Pfdhps (dihydropteroate synthase) genes are widely used for SPR surveillance. This study aimed to assess the prevalence of Pfdhfr and Pfdhps genes mutations and haplotypes in Plasmodium falciparum isolates collected from Bioko Island, Equatorial Guinea (EG).

METHODS

In total, 180 samples were collected in 2013-2014. The single nucleotide polymorphisms (SNPs) of the Pfdhfr and Pfdhps genes were identified with nested PCR and Sanger sequencing. The genotypes and linkage disequilibrium (LD) tests were also analysed.

RESULTS

Sequences of Pfdhfr and Pfdhps genes were obtained from 92.78% (167/180) and 87.78% (158/180) of the samples, respectively. For Pfdhfr, 97.60% (163/167), 87.43% (146/167) and 97.01% (162/167) of the samples carried N51I, C59R and S108N mutant alleles, respectively. The prevalence of the Pfdhps S436A, A437G, K540E, A581G, and A613S mutations were observed in 20.25% (32/158), 90.51% (143/158), 5.06% (8/158), 0.63% (1/158), and 3.16% (5/158) of the samples, respectively. In total, 3 unique haplotypes at the Pfdhfr locus and 8 haplotypes at the Pfdhps locus were identified. A triple mutation (CIRNI) in Pfdhfr was the most prevalent haplotype (86.83%), and a single mutant haplotype (SGKAA; 62.66%) was predominant in Pfdhps. A total of 130 isolates with 12 unique haplotypes were found in the Pfdhfr and Pfdhps combined haplotypes, 65.38% (85/130) of them carried quadruple allele combinations (CIRNI-SGKAA), whereas only one isolate (0.77%, 1/130) was found to carry the wild-type (CNCSI-SAKAA). For LD analysis, the Pfdhfr N51I was significantly associated with the Pfdhps A437G (P < 0.05).

CONCLUSION

Bioko Island possesses a high prevalence of the Pfdhfr triple mutation (CIRNI) and Pfdhps single mutation (SGKAA), which will undermine the pharmaceutical effect of SP for malaria treatment strategies. To avoid an increase in SPR, continuous molecular monitoring and additional control efforts are urgently needed in Bioko Island, Equatorial Guinea.

Environmental and sociodemographic factors associated with household malaria burden in the Congo

Background

Malaria is one of the most severe public health issues that result in massive morbidity and mortality in most countries of the sub-Saharan Africa (SSA). This study aimed to determine the scope of household, accessibility to malaria care and factors associated with household malaria in the Democratic Republic of Congo (DRC).

Methods

This was a community-based cross-sectional study conducted in an urban and a rural sites in which 152 households participated, including 82 urban and 70 rural households (1029 members in total). The ‘malaria indicator questionnaire’ (MIQ) was anonymously answered by household heads (respondents), reporting on malaria status of household members in the last 12 months.

Results

There were 67.8% of households using insecticide-treated bed nets (ITN) only, 14.0% used indoor residual spraying (IRS) only, 7.3% used ordinary bed nets (without insecticide treatment), 1.4% used mosquito repelling cream, 2.2% combined ITN and IRS, whereas 7.3% of households did not employ any preventive measure; p < 0.01). In addition, 96.7% of households were affected by malaria (at least one malaria case), and malaria frequency per household was relatively high (mean: 4.5 ± 3.1 cases reported) in the last 12 months. The mean individual malaria care expenditure was relatively high (101.6 ± 10.6 USD) in the previous 12 months; however, the majority of households (74.5%) earned less than 50 USD monthly. In addition, of the responders who suffered from malaria, 24.1% did not have access to malaria care at a health setting. Furthermore, a multivariate analysis with adjustment for age, education level and occupation showed that household size (OR = 1.43 ± 0.13; 95% CI 1.18–1.73; p < 0.001), inappropriate water source (OR = 2.41 ± 0.18; 95% CI 1.17–2.96; p < 0.05) absence of periodic water, sanitation and hygiene (WASH) intervention in residential area (OR = 1.63 ± 1.15; 95% CI 1.10–2.54; p < 0.05), and rural residence (OR = 4.52 ± 2.47; 95% CI 1.54–13.21; p < 0.01) were associated with household malaria.

Conclusion

This study showed that household size, income, WASH status and rural site were malaria-associated factors. Scaling up malaria prevention through improving WASH status in the residential environment may contribute to reducing the disease burden.