High prevalence and risk of malaria among asymptomatic individuals from villages with high rates of artemisinin partial resistance in Kyerwa district, North-western Tanzania

Abstract

BackgroundTanzania adopted and has been implementing the World Health Organization (WHO) recommended interventions to control and eventually eliminate malaria. However, malaria is still a leading public health problem and the country experiences heterogeneous transmission; but the drivers of these patterns are not clearly known. This study assessed the prevalence and risk of malaria infections among asymptomatic individuals living in a hyperendemic area which has high prevalence of artemisinin partial resistant parasites in Kyerwa District of Kagera region, North-western Tanzania.MethodsThis was a community-based cross-sectional survey that recruited participants from five villages of Kyerwa district in Kagera region. Demographic, anthropometric, clinical, parasitological, types of houses inhabited and socio-economic status (SES) data were collected using electronic capture tools running on Open Data Kit (ODK). Risk factors associated with malaria infections were determined by univariate and multivariate logistic regression and the results were presented as crude (cOR) and adjusted Odds Ratio (aOR), with 95% confidence intervals (CI).ResultsA total of 4,454 individuals were tested using malaria rapid diagnostic tests (RDTs) and 1,979 (44.4%) had a positive test. The prevalence of malaria varied from 14.4% to 68.5% with significant differences among the villages (p<0.001). The prevalence and risk of malaria infections were significantly higher in males (aOR =1.25, 95% CI: 1.06 - 1.48, p=0.04), school children ((aged 5 – 10 years, aOR =4.09, 95% CI: 3.39 – 5.10, p<0.001) and (10-15 years, aOR=4.40, 95% CI: 3.46 – 5.59, p<0.001)) and among individuals who were not using bed nets (aOR =1.29, 95% CI: 1.10 – 1.42, p=0.002). Other risks of malaria infections included lower SES (aOR=1.27, 95% CI:1.04 – 1.55, p<0.001) and living in houses with open windows (aOR=1.26, 95% CI: 1.03 −1.54, p=0.024).ConclusionThis study showed high prevalence of malaria infections and high heterogeneity at micro-geographic levels. The risk of malaria infections was higher in school children, males, individuals who did not use bed nets, and among participants with low SES or living in poorly constructed houses. These findings provide important baseline data in an area with a high prevalence of artemisinin partial-resistant parasites and will be utilized in future studies to monitor the trends and potential spread of such parasites.

Prevalence and risk factors associated with malaria infections at a micro-geographic level in three villages of Muheza district, north-eastern Tanzania

“…While malaria burden stratification has been undertaken using both community parasite prevalence and routine health service data primarily over large geographic areas [28], some evidence indicates that spatial and temporal variations at micro-geographic levels also exist [29,30] but these have not been included in the initiatives pursued by NMCP in Tanzania. A recent study conducted in an area of high malaria transmission in north-western Tanzania highlighted marked differences in malaria prevalence within a small geographic area [31]. Other studies conducted within the country supported the same findings of high malaria prevalence with wide variations at microgeographic levels [15,32].…”

“…For under-fives, the government still implements the scheme of providing bed nets through the ANC clinics and also free health care that covers case management services, focusing on prompt diagnosis using RDTs and effective treatment for malaria using ACTs [56]. Despite these initiatives, the burden of malaria is still higher in school children compared to other groups [31] and the reasons for this are not known and urgent measures are required to generate more evidence and factors responsible for this pattern. In addition, efforts and strategies are needed to fully assess, understand, and support NMCP to implement appropriate interventions to reduce the burden of malaria in this group.…”

“…Females also have more awareness of and high health-seeking behaviour compared to men due to their roles as caretakers of children and their families [63]. Although these factors may have contributed to the potential lower risk of malaria infections among females, some studies have shown contradictory findings with reports of the high prevalence of malaria in females, as recently shown in one of the villages of Kyerwa district in Kagera region [31] and another from Nyasa district in Ruvuma region [64]. Thus, more studies may be needed to confirm these findings and provide evidence of the high vulnerability of males to malaria infections so that this group can also be targeted with malaria interventions such as those aimed at reducing the overall vector abundance and/or protecting them from outdoor biting…”

“…The data collected included household information, characteristics of the houses such as types and conditions of the houses (walls, roofing, floor and windows building materials status), the environment around the household (land use, vegetation cover, and breeding sites as well as large water bodies) and geo-referenced data of each household. The CSS data were collected during the CSS as described earlier and using a similar workflow with station-specific activities [31]. Eligibility criteria included age from 6 months and above, residence in the study village, and provision of informed consent.…”

“…This study targeted about 30% of all individuals aged >5 months from all HHs covered during the census done in 2013 (updated in 2021) using the MSMT protocol as described elsewhere [31]. All study participants were residents of the three villages in Muheza district (Magoda, Mamboleo, and Mpapayu) which are under the MSMT project.…”