Spatio-temporal prevalence of malaria and anaemia in relation to agro-ecosystems in Mvomero district, Tanzania

A comprehensive review of antimalarial medicinal plants used by Tanzanians

CONTEXT

Tanzania has rich medicinal plant (MP) resources, and most rural inhabitants rely on traditional healing practices for their primary healthcare needs. However, available research evidence on antimalarial MPs is highly fragmented in the country.

OBJECTIVE

This systematic review compiles ethnomedicinal research evidence on MPs used by Tanzanians as antimalarials.

MATERIALS AND METHODS

A systematic web search was conducted using various electronic databases and grey materials to gather relevant information on antimalarial MPs utilized by Tanzanians. The review was per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The data were collected from 25 articles, and MS Excel software was used to analyse relevant ethnobotanical information using descriptive statistics.

RESULTS

A total of 227 MPs belonging to 67 botanical families and 180 genera were identified. Fabaceae (15.9%) is the most frequently utilized family. The ethnobotanical recipes analysis indicated leaves (40%) and trees (44%) are the preferred MPs part and life form, respectively. Decoctions (67%) are the dominant preparation method of remedies. Of the recorded MPs, 25.9% have been scientifically investigated for antimalarial activities with positive results. However, 74.1% of MPs have no scientific records on antimalarial activities, but they could be potential sources of remedies.

CONCLUSIONS

The study discloses a wealth of antimalarial MPs possessed by Tanzanians and suggests a need for research to authenticate the healing potential of antimalarial compounds from the unstudied MPs. Additionally, it indicates that some of the presented MPs are potential sources for developing safe, effective and affordable antimalarial drugs.

Geographic inequalities and determinants of anaemia among preeclamptic women: a cross-sectional sample-based study in Bangladesh

BACKGROUND

Anaemia among preeclamptic (PE) women is a major undefined health issue in Bangladesh. This study explored the risk factors associated with anaemia and mapped the regional influences to understand the geographical inequalities.

METHODS

Data from 180 respondents were prospectively collected from the Preeclampsia ward of Dhaka Medical College Hospital (DMCH), Bangladesh. Anaemia was defined as a blood haemoglobin level less than 11.0 g/dl. Preeclampsia was defined as systolic blood pressure (SBP) ≥ 140 mmHg and diastolic blood pressure (DBP) ≥ 90 mmHg with proteinuria. Factors associated with anaemia were explored using the chi-square test. Logistic regression (LR) was done to determine the level of association with the risk factors.

RESULTS

Among the participants, 28.9% were identified as having early onset and 71.1% reported late onset of PE. 38.9% of the subjects were non-anaemic, whereas mild, moderate, and severe anaemia was found among 38.3%, 17.8%, and 5% of patients respectively. The following factors were identified; including age range 25-34 (OR: 0.169, p < 0.05), a lower education level (OR: 3.106, p < 0.05), service-holder mothers (OR: 0.604, p < 0.05), pregnancy interval of less than 24 months (OR: 4.646, p < 0.05), and gestational diabetes mellitus (OR: 2.702, p < 0.05). Dhaka district (IR: 1.46), Narayanganj district (IR: 1.11), and Munshiganj district (IR: 0.96) had the highest incidence rates.

CONCLUSION

Determinants of anaemia must be considered with importance. In the future, periodic follow-ups of anaemia should be scheduled with a health care program and prevent maternal fatality and fetus morbidity in patients with PE.

Asymptomatic and submicroscopic malaria infections in sugar cane and rice development areas of Ethiopia

BACKGROUND

Water resource development projects, such as dams and irrigation schemes, have a positive impact on food security and poverty reduction. However, such projects could increase prevalence of vector borne disease, such as malaria. This study investigate the impact of different agroecosystems and prevalence of malaria infection in Southwest Ethiopia.

METHODS

Two cross-sectional surveys were conducted in the dry and wet seasons in irrigated and non-irrigated clusters of Arjo sugarcane and Gambella rice development areas of Ethiopia in 2019. A total of 4464 and 2176 study participants from 1449 households in Arjo and 546 households in Gambella enrolled in the study and blood samples were collected, respectively. All blood samples were microscopically examined and a subset of microscopy negative blood samples (n = 2244) were analysed by qPCR. Mixed effect logistic regression and generalized estimating equation were used to determine microscopic and submicroscopic malaria infection and the associated risk factors, respectively.

RESULTS

Prevalence by microscopy was 2.0% (88/4464) in Arjo and 6.1% (133/2176) in Gambella. In Gambella, prevalence was significantly higher in irrigated clusters (10.4% vs 3.6%) than in non-irrigated clusters (p < 0.001), but no difference was found in Arjo (2.0% vs 2.0%; p = 0.993). On the other hand, of the 1713 and 531 samples analysed by qPCR from Arjo and Gambella the presence of submicroscopic infection was 1.2% and 12.8%, respectively. Plasmodium falciparum, Plasmodium vivax, and Plasmodium ovale were identified by qPCR in both sites. Irrigation was a risk factor for submicroscopic infection in both Arjo and Gambella. Irrigation, being a migrant worker, outdoor job, < 6 months length of stay in the area were risk factors for microscopic infection in Gambella. Moreover, school-age children and length of stay in the area for 1-3 years were significant predictors for submicroscopic malaria in Gambella. However, no ITN utilization was a predictor for both submicroscopic and microscopic infection in Arjo. Season was also a risk factor for microscopic infection in Arjo.

CONCLUSION

The study highlighted the potential importance of different irrigation practices impacting on submicroscopic malaria transmission. Moreover, microscopic and submicroscopic infections coupled with population movement may contribute to residual malaria transmission and could hinder malaria control and elimination programmes in the country. Therefore, strengthening malaria surveillance and control by using highly sensitive diagnostic tools to detect low-density parasites, screening migrant workers upon arrival and departure, ensuring adequate coverage and proper utilization of vector control tools, and health education for at-risk groups residing or working in such development corridors is needed.

Asymptomatic and submicroscopic malaria infections in sugar cane and rice development areas of Ethiopia

Background

Water resource development projects such as dams and irrigation schemes have a positive impact on food security and poverty reduction but might result in increased prevalence of malaria.

Methods

Two cross-sectional surveys were conducted in the dry and wet seasons in irrigated and non-irrigated clusters of Arjo sugarcane and Gambella rice development areas of Ethiopia in 2019. A total of 4464 and 2176 blood samples were collected from Arjo and Gambella. A subset of 2244 microscopy negative blood samples were analyzed by PCR.

Results

Prevalence by microscopy was 2.0% (88/4464) in Arjo and 6.1% (133/2176) in Gambella. In Gambella, prevalence was significantly higher in irrigated clusters (10.4% vs 3.6%) than in non-irrigated clusters (p < 0.001), but no difference was found in Arjo (2.0% vs 2.0%; p = 0.993). Level of education was an individual risk factors associated with infection in Arjo [AOR: 3.2; 95%CI (1.27-8.16)] and in Gambella [AOR: 1.7; 95%CI (1.06-2.82)]. While duration of stay in the area for < 6 months [AOR: 4.7; 95%CI (1.84-12.15)] and being a migrant worker [AOR: 4.7; 95%CI (3.01-7.17)] were risk factors in Gambella. Season [AOR: 15.9; 95%CI (6.01-42.04)], no ITN utilization [AOR: 22.3; 95%CI (7.74-64.34)] were risk factors in Arjo, and irrigation [AOR: 2.4; 95%CI (1.45-4.07)] and family size [AOR: 2.3; 95%CI (1.30-4.09)] risk factors in Gambella. Of the 1713 and 531 randomly selected smear negative samples from Arjo and Gambella and analyzed by PCR the presence of Plasmodium infection was 1.2% and 12.8%, respectively. P. falciparum, P. vivax, and P. ovale were identified by PCR in both sites.

Conclusion

Strengthening malaria surveillance and control in project development areas and proper health education for at-risk groups residing or working in such development corridors is needed.

Irrigation-Induced Environmental Changes Sustain Malaria Transmission and Compromise Intervention Effectiveness

BACKGROUND

Irrigated agriculture enhances food security, but it potentially promotes mosquito-borne disease transmission and affects vector intervention effectiveness. This study was conducted in the irrigated and nonirrigated areas of rural Homa Bay and Kisumu Counties, Kenya.

METHODS

We performed cross-sectional and longitudinal surveys to determine Plasmodium infection prevalence, clinical malaria incidence, molecular force of infection (molFOI), and multiplicity of infection. We examined the impact of irrigation on the effectiveness of the new interventions.

RESULTS

We found that irrigation was associated with >2-fold higher Plasmodium infection prevalence and 3-fold higher clinical malaria incidence compared to the nonirrigated area. Residents in the irrigated area experienced persistent, low-density parasite infections and higher molFOI. Addition of indoor residual spraying was effective in reducing malaria burden, but the reduction was more pronounced in the nonirrigated area than in the irrigated area.

CONCLUSIONS

Our findings collectively suggest that irrigation may sustain and enhance Plasmodium transmission and affects intervention effectiveness.

Bayesian spatio-temporal modelling and mapping of malaria and anaemia among children between 0 and 59 months in Nigeria

BACKGROUND/M&M

A vital aspect of disease management and policy making lies in the understanding of the universal distribution of diseases. Nevertheless, due to differences all-over host groups and space-time outbreak activities, data are subject to intricacies. Herein, Bayesian spatio-temporal models were proposed to model and map malaria and anaemia risk ratio in space and time as well as to ascertain risk factors related to these diseases and the most endemic states in Nigeria. Parameter estimation was performed by employing the R-integrated nested Laplace approximation (INLA) package and Deviance Information Criteria were applied to select the best model.

RESULTS

In malaria, model 7 which basically suggests that previous trend of an event cannot account for future trend i.e., Interaction with one random time effect (random walk) has the least deviance. On the other hand, model 6 assumes that previous event can be used to predict future event i.e., (Interaction with one random time effect (ar1)) gave the least deviance in anaemia.

DISCUSSION

For malaria and anaemia, models 7 and 6 were selected to model and map these diseases in Nigeria, because these models have the capacity to receive strength from adjacent states, in a manner that neighbouring states have the same risk. Changes in risk and clustering with a high record of these diseases among states in Nigeria was observed. However, despite these changes, the total risk of malaria and anaemia for 2010 and 2015 was unaffected.

CONCLUSION

Notwithstanding the methods applied, this study will be valuable to the advancement of a spatio-temporal approach for analyzing malaria and anaemia risk in Nigeria.

Impact of Agricultural Irrigation on Anemia in Western Kenya

Expanding agricultural irrigation efforts to enhance food security and socioeconomic development in sub-Saharan Africa may affect malaria transmission and socioeconomic variables that increase the risk of anemia in local communities. We compared the prevalence of anemia, Plasmodium falciparum infection, and indicators of socioeconomic status related to nutrition in communities in Homa Bay County, Kenya, where an agricultural irrigation scheme has been implemented, to that in nearby communities where there is no agricultural irrigation. Cross-sectional surveys conducted showed that anemia prevalence defined by WHO criteria (hemoglobin < 11 g/dL) was less in communities in the irrigated areas than in the non-irrigated areas during the wet season (38.9% and 51.5%, χ2 = 4.29, P = 0.001) and the dry season (25.2% and 34.1%, χ2 = 7.33, P = 0.007). In contrast, Plasmodium falciparum infection prevalence was greater during the wet season in irrigated areas than in non-irrigated areas (15.3% versus 7.8%, χ2 = 8.7, P = 0.003). There was, however, no difference during the dry season (infection prevalence, < 1.8%). Indicators of nutritional status pertinent to anemia pathogenesis such as weekly consumption of non-heme- and heme-containing foods and household income were greater in communities located within the irrigation scheme versus those outside the irrigation scheme (P < 0.0001). These data indicate that current agricultural irrigation schemes in malaria-endemic communities in this area have reduced the risk of anemia. Future studies should include diagnostic tests of iron deficiency, parasitic worm infections, and genetic hemoglobin disorders to inform public health interventions aimed at reducing community anemia burden.

Evaluating malaria prevalence and land cover across varying transmission intensity in Tanzania using a cross-sectional survey of school-aged children

BACKGROUND

Transmission of malaria in sub-Saharan Africa has become increasingly stratified following decades of malaria control interventions. The extent to which environmental and land cover risk factors for malaria may differ across distinct strata of transmission intensity is not well known and could provide actionable targets to maximize the success of malaria control efforts.

METHODS

This study used cross-sectional malaria survey data from a nationally representative cohort of school-aged children in Tanzania, and satellite-derived measures for environmental features and land cover. Hierarchical logistic regression models were applied to evaluate associations between land cover and malaria prevalence within three distinct strata of transmission intensity: low and unstable, moderate and seasonal, and high and perennial.

RESULTS

In areas with low malaria transmission, each 10-percentage point increase in cropland cover was associated with an increase in malaria prevalence odds of 2.44 (95% UI: 1.27, 5.11). However, at moderate and higher levels of transmission intensity, no association between cropland cover and malaria prevalence was detected. Small associations were observed between greater grassland cover and greater malaria prevalence in high intensity settings (prevalence odds ratio (POR): 1.10, 95% UI: 1.00, 1.21), and between greater forest cover and reduced malaria prevalence in low transmission areas (POR: 0.74, 95% UI: 0.51, 1.03), however the uncertainty intervals of both estimates included the null.

CONCLUSIONS

The intensity of malaria transmission appears to modify relationships between land cover and malaria prevalence among school-aged children in Tanzania. In particular, greater cropland cover was positively associated with increased malaria prevalence in areas with low transmission intensity and presents an actionable target for environmental vector control interventions to complement current malaria control activities. As areas are nearing malaria elimination, it is important to re-evaluate environmental risk factors and employ appropriate interventions to effectively address low-level malaria transmission.

Malaria transmission and prevalence in rice-growing versus non-rice-growing villages in Africa: a systematic review and meta-analysis

BACKGROUND

Rice fields in Africa are major breeding sites for malaria vectors. However, when reviewed in the 1990s, in settings where transmission was relatively intense, there was no tendency for malaria indices to be higher in villages with irrigated rice fields than in those without. Subsequently, intervention coverage in sub-Saharan Africa has been massively scaled up and malaria infection prevalence has halved. We re-examined this rice-malaria relationship to assess whether, with lower malaria transmission, malaria risk is greater in rice-growing than in non-rice-growing areas.

METHODS

For this systematic review and meta-analysis, we searched EMBASE, Global Health, PubMed, Scopus, and Web of Science to identify observational studies published between Jan 1, 1900, and Sept 18, 2020. Studies were considered eligible if they were observational studies (cross-sectional, case-control, or cohort) comparing epidemiological or entomological outcomes of interest between people living in rice-growing and non-rice-growing rural communities in sub-Saharan Africa. Studies with pregnant women, displaced people, and military personnel as participants were excluded because they were considered not representative of a typical community. Data were extracted with use of a standardised data extraction form. The primary outcomes were parasite prevalence (P falciparum parasite rate age-standardised to 2-10-year-olds, calculated from total numbers of participants and number of infections [confirmed by microscopy or rapid diagnostic test] in each group) and clinical malaria incidence (number of diagnoses [fever with Plasmodium parasitaemia confirmed by microscopy or rapid diagnostic test] per 1000 person-days in each group). We did random-effects meta-analyses to estimate the pooled risk ratio (RR) for malaria parasite prevalence and incidence rate ratio (IRR) for clinical malaria in rice-growing versus non-rice-growing villages. RRs were compared in studies conducted before and after 2003 (chosen to mark the start of the mass scale-up of antimalaria interventions). This study is registered with PROSPERO (CRD42020204936).

FINDINGS

Of the 2913 unique studies identified and screened, 53 studies (including 113 160 participants across 14 African countries) were eligible for inclusion. In studies done before 2003, malaria parasite prevalence was not significantly different in rice-growing versus non-rice-growing villages (pooled RR 0·82 [95% CI 0·63-1·06]; 16 studies, 99 574 participants); however, in post-2003 studies, prevalence was significantly higher in rice-growing versus non-rice growing villages (1·73 [1·01-2·96]; seven studies, 14 002 participants). Clinical malaria incidence was not associated with residence in rice-growing versus non-rice-growing areas (IRR 0·75 [95% CI 0·47-1·18], four studies, 77 890). Potential limitations of this study include its basis on observational studies (with evidence quality rated as very low according to the GRADE approach), as well as its omission for the effects of seasonality and type of rice being cultivated. Risk of bias and inconsistencies was relatively serious, with I2 greater than 90% indicating considerable heterogeneity.

INTERPRETATION

Irrigated rice-growing communities in sub-Saharan Africa are exposed to greater malaria risk, as well as more mosquitoes. As increasing rice production and eliminating malaria are two major development goals in Africa, there is an urgent need to improve methods for growing rice without producing mosquitoes.

FUNDING

Wellcome Trust Our Planet Our Health programme, CGIAR Agriculture for Nutrition and Health.

When Local Trade-Offs between SDGs Turn Out to Be Wealth-Dependent: Interaction between Expanding Rice Cultivation and Eradicating Malaria in Rwanda

Interactions between SDGs are increasingly mapped and mediating factors that determine whether existing synergies or trade-offs can be identified. However, if and how the wealth status of the concerned population shapes whether SDG interaction constitutes a vicious or virtuous circle is largely overlooked. This article focuses on interaction between SDG2 (nutrition) and SDG3 (health), in particular, the relationship between rice production intensification and the fight against malaria, and thus the role of wealth in explaining the trade-off. This study employed a large-scale survey of rural households (n = 3968) in eastern Rwanda, conducted at a time when a rapid expansion of rice fields co-existed with a strong resurgence of malaria. Logistic regression shows that rice-cultivating households faced significant higher malaria risk, as proxied by fever incidence, confirming the negative externality of agricultural intensification on public health through offering a habitat for vector-borne diseases. Even though rice-cultivating households tend to be higher up the local wealth distribution than those outside the rice sector, its distributional effects are generally biased against the poor. Poorer households outside the rice sector hardly share in the benefits from increased rice production but suffer the consequences in terms of increased malaria risk. The case thus draws attention to the importance of using a distributional lens when analyzing interaction between SDGs locally.

Prevalence, Parasite Density and Determinants of Falciparum Malaria Among Febrile Children in Some Peri-Urban Communities in Southwestern Nigeria: A Cross-Sectional Study

Background

Malaria remains a serious public health problem worldwide, particularly in tropical and subtropical regions, including Nigeria. This study investigates the prevalence, parasite density and determinants of malaria among symptomatic children in some peri-urban communities in southwestern Nigeria.

Methods

This was a randomized cross-sectional and hospital-based study. The standard method of microscopy was employed. Thick and thin films were prepared and viewed under a light microscope to identify and quantify malaria parasites. A well-structured and pre-tested questionnaire was used to obtain the subject’s information on the demographic, socio-economic and environmental variables.

Results

A total of 380 (71.7%) participants were infected with Plasmodium falciparum with a mean parasite density of 1857.11 parasite/µL of blood. Malaria prevalence and mean parasite density were significantly higher among male compared to their female counterparts [80.3% vs 61.4% and 2026.46 vs 1619.63 parasite/µL of blood]. Similarly, age group ≤5 years had the highest malaria prevalence (92.2%) and mean parasite density (2031.66 parasite/µL of blood) than other age groups (AOR 2.281, 95% CI: 1.187–4.384, P < 0.05). The multivariate logistic analysis showed that malaria disease is significantly associated with having mother with no formal education (AOR 12.235, 95% CI: 3.253–46.021, P < 0.05), having well and river as a major source of household water supply (AOR 13.810, 95% CI: 3.012–63.314, P < 0.05 vs AOR 5.639, 95% CI: 1.455–21.853, P < 0.05) and presence of stagnant water around home (AOR 5.22, 95% CI: 2.921–9.332, P < 0.05). Furthermore, protective factors observed include ownership of mosquito bed net (AOR 0.474, 95% CI: 0.223–1.008, P < 0.05) and distance of home to hospital (AOR 0.279, 95% CI: 0.158–0.493, P < 0.05).

Conclusion

Malaria remains a serious public health problem in the study area. Adopting integrated malaria control measures including educating parents on malaria prevention and control strategies, distributing mosquito bed nets, and establishing larvae source management program is highly imperative.

Multilevel modelling of the risk of malaria among children aged under five years in Nigeria

BACKGROUND

Malaria is still a major cause of morbidity and mortality among children aged <5 y (U5s). This study assessed individual, household and community risk factors for malaria in Nigerian U5s.

METHODS

Data from the Nigerian Malaria Health Indicator Survey 2015 were pooled for analyses. This comprised a national survey of 329 clusters. Children aged 6-59 mo who were tested for malaria using microscopy were retained. Multilevel logit model accounting for sampling design was used to assess individual, household and community factors associated with malaria parasitaemia.

RESULTS

A total of 5742 children were assessed for malaria parasitaemia with an overall prevalence of 27% (95% CI 26 to 28%). Plasmodium falciparum constituted 98% of the Plasmodium species. There was no significant difference in parasitaemia between older children and those aged ≤12 mo. In adjusted analyses, rural living, northwest region, a household size of >7, dependence on river and rainwater as primary water source were associated with higher odds of parasitaemia, while higher wealth index, all U5s who slept under a bed net and dependence on packaged water were associated with lower odds of parasitaemia.

CONCLUSION

Despite sustained investment in malaria control and prevention, a quarter of the overall study population of U5s have malaria. Across the six geopolitical zones, the highest burden was in children living in the poorest rural households.

Performance evaluation of Kuroiler and Sasso chicken breeds reared under farmer management conditions in highland and lowland areas of Mvomero district, Eastern Tanzania

One thousand one hundred and fifty-two dual-purpose improved chickens (576 Kuroiler and 576 Sasso) of mixed sexes were reared in two diverse agro-ecological zones, i.e., highland and lowland in Mvomero district, Eastern Tanzania, to determine the effects of agro-ecological zones on growth performance, egg production, and survivability under farmer management conditions. Two villages per zone were purposively selected, and from each village, 16 farmers were included in the study; a particular farmer received 18 birds of mixed sexes of the same breed. Data on body weight, egg production trait, and mortality were taken at different ages from week 6 up to 52. General Linear Models fitting breed, agro-ecological zone, and interactions between breed and zone were used to analyze the data. Results show that breed had no significant effects on body weight and body weight gain. However, the effects of the agro-ecological zone and interaction between breed and zone on body weight and body weight gain were significant at the 16th and 20th week of age. The highland zone had heavier chickens than the lowland. While Sasso performed better than Kuroiler chickens in the highland zone, the opposite was observed in the lowland. Significant breed × agro-ecology interactions were observed only for age at first egg whereby Sasso matured earlier than Kuroiler in the highland zone but much later than Kuroiler in the lowland. Birds raised in the highland zone survived better than those chickens in the lowland during both growing and laying periods. Thus, knowledge of breed performance in relation to agro-ecological differences is critical when distributing improved chicken breeds to farmers.

Is the source of domestic water associated with the risk of malaria infection? Spatial variability and a mixed-effects multilevel analysis

BACKGROUND

There is a dearth of information on the relationship between domestic water source and malaria infection in malaria-endemic regions such as Tanzania. This study examined the geospatial variability and association between domestic water source and malaria prevalence in Tanzania.

METHODS

We analyzed data from a sample of 6707 children, aged 6-59 months, from the 2017 Tanzania Malaria Indicator Survey. The outcome variable was the result of malaria testing (positive or negative) and the main explanatory variable was domestic water source (piped or non-piped). Random effect variables were administrative region and geographical zone. ArcGIS 10.7 was used to create geospatial distribution maps. A STATA MP 14.0 was used to fit a mixed-effects multilevel logistic regression to examine the factors associated with malaria prevalence.

RESULTS

The prevalence of malaria and non-piped domestic water source was respectively 7.3% and 59.6%. The regions and zones with a higher prevalence of malaria also had a higher percentage of non-piped water. There was a statistically significant variation in the risk of malaria across the regions (variance = 1.27; 95% CI, 0.40-4.07) and zones (variance = 4.75; 95% CI, 1.46-15.46). The final fixed-effects model showed that non-piped domestic water was significantly associated with malaria prevalence (adjusted odds ratio (AOR) = 2.18; 95% CI, 1.64-2.89; P < 0.001).

CONCLUSIONS

A non-piped source of domestic water was independently associated with positive testing for malaria. Moreover, regions with a high percentage of non-piped domestic water had a correspondingly high prevalence of malaria.

Retrospective Analysis of Malaria Cases in a Potentially High Endemic Area of Morogoro Rural District, Eastern Tanzania

Background

Malaria is increasingly characterized by appreciable fine-scale variability in ecology and topography, and it is likely that we are missing some salient foci with unprecedented malaria transmission intensity in different parts of Tanzania. Therefore, efforts aimed at identifying area-specific malaria situation and intervening are needed to preserve the realized health gains and achieve elimination. Mkuyuni and Kiroka, adjacent wards within Morogoro Rural District, are purported to form one of such foci.

Patients and Methods

A retrospective study was conducted to determine six-year (2014-2019) malaria prevalence rates based on outpatients and laboratory registers obtained from two health facilities, one per ward, carrying out diagnosis of malaria either through microscopy or malaria rapid diagnostic test (mRDT). These data were checked for completeness before carrying out statistical analysis.

Results

Overall, 35,386 (46.19%) out of 76,604 patients were positive for malaria. The average proportion of malaria cases was significantly higher in Mkuyuni (51.23%; n=19,438) than Kiroka (41.21%; n = 15,938) (P <0.001). Females were more affected than males (P <0.001);, and irrespective of the sex, most malaria cases were recorded in children <5 years of age (P <0.001) except at Mkuyuni. Malaria was recorded virtually all year round; however, the highest proportion of cases was recorded in April and July (P <0.001).

Conclusion

This study revealed high malaria endemicity in Mkuyuni and Kiroka, with prevalence rate as high as 60.98%, which is far higher than the overall national average prevalence of 9%. More studies are needed in these and other putatively high endemic foci in Tanzania in order to inform the future course of action in disease surveillance and control.

Geo-Epidemiology of Malaria at the Health Area Level, Dire Health District, Mali, 2013-2017

Background: According to the World Health Organization, there were more than 228 million cases of malaria globally in 2018, with 93% of cases occurring in Africa; in Mali, a 13% increase in the number of cases was observed between 2015 and 2018; this study aimed to evaluate the impact of meteorological and environmental factors on the geo-epidemiology of malaria in the health district of Dire, Mali. Methods: Meteorological and environmental variables were synthesized using principal component analysis and multiple correspondence analysis, the relationship between malaria incidence and synthetic indicators was determined using a multivariate general additive model; hotspots were detected by SaTScan. Results: Malaria incidence showed high inter and intra-annual variability; the period of high transmission lasted from September to February; health areas characterized by proximity to the river, propensity for flooding and high agricultural yield were the most at risk, with an incidence rate ratio of 2.21 with confidence intervals (95% CI: 1.85-2.58); malaria incidence in Dire declined from 120 to 20 cases per 10,000 person-weeks between 2013 and 2017. Conclusion: The identification of areas and periods of high transmission can help improve malaria control strategies.