Prevalence and determinants of malaria infection among children of local farmers in Central Malawi

The study was implemented in six postnatal clinics in the Dowa district of central Malawi in southern Africa (Fig. 1). Malawi has a population of about 17,563,749 people [8]. In 2017, about 71% of the population was living in extreme poverty according to United Nations indicators [10]. Malaria is an endemic disease in Dowa and surrounding districts, but higher numbers of cases are recorded during and after the rainy season (December to July) due to increased potential breeding environments [9, 11]. This study was conducted between May and September 2018 because this period would allow to capturing of average malaria cases in the study areas.

A multistage, descriptive, cross-sectional study design was employed to select a representative sample of children aged 2 to 59 months and their mothers in the Dowa district. A random selection of 6 out of 8 outreach clinics that were part of the Mvera mission hospital was conducted. The selected clinics were located in Gogo, Ching’amba, Mkhalanjoka, Kalinyengo, Mvera and Mphande, within approximately 5–10 km of the Mvera mission hospital. During the study, the Mvera mission hospital served a population of 27,719 people, of whom 5240 were mothers with a child under 5 years old. A total population of 4527 mothers with children between 2 and 59 months were identified in postnatal registers in the 6 randomly selected postnatal clinics. The sample size was determined by a Raosoft sample size calculator [12]. A margin of error of 5% with a 95% confidence level and 50% response distribution was set. A systematic sampling strategy was used to select a sample of 523 children and their mothers from the postnatal registers. The first child-mother dyad was randomly picked and subsequently every 9th child-mother dyad were selected.

Selected mothers and their children were contacted at the 6 postnatal clinics during the regular monthly health screening for children. The screening programme is an initiative of the Malawi Government to promote maternal and child health through a framework of a continuum of care for mothers, newborns and children [13]. Community health workers who were assigned as research assistants sought informed consent from mothers to take part in the study. All interviews took place in the consultation room at each outreach postnatal clinic using a pre-tested questionnaire. The questionnaire contained questions on household socio-demographic characteristics, household food security, house structure type, use of mosquito nets, and maternal exposure to intimate partner violence (IPV). The child’s and the mother’s anthropometric and health status data from their health passports were recorded in the questionnaire after their health screening programme was completed [14].

The main outcome variable of the study was malaria infection in children 2 to 59 months old. The term child malaria infection was operationalized as the presence of the malaria parasite in children’s red blood cells as recorded in the child’s health passport [15]. In all the postnatal clinics, RDTs were used to assess the malaria parasitaemia in children. If the diagnostic test was positive, the child was coded as 1 = malaria infection, and 0 = otherwise.

Ethics approval to conduct this study was obtained from the University of Livingstonia research ethics committee in Malawi (protocol number: UNILIA-REC-4/18) and the Research Ethics Board of McGill University in Canada (protocol number: REB File #: 503-0518). Written permission was also sought from the Dowa district commissioner’s office, the Dowa district health office and the Mvera mission hospital management. Oral consent was obtained from local health leaders and research participants in the study areas.

The Kolmogorov–Smirnov test was used to test the normality of the distribution of numerical variables. These include age, number of children, number of household members, and household food security. Categorical variables were constructed from the numerical data because the data were not normally distributed [28]. Bivariate logistic regressions were performed to examine significant predictors of child malaria. Significant predictors of child malaria at the bivariate level of (p  < 0.05) were included in the final multivariable logistic regression model using the forward enter method.

Socio-demographic and malaria infection data for all 523 selected children aged 2 to 59 months were obtained over 4 months (see Table 1). In terms of gender, 49.1% of the children were girls and 50.9% were boys. In terms of age, 13.4% of the sample was aged 2 to 5 months, 17.2% was aged 6 to 11 months, 29.6% was aged 12 to 23 months, and 41.9% was aged 24 to 59 months. It was observed that 14.3% of the selected children were born with a low birth weight (birth weight of less than 2.5 kg); 27.2% of the mothers reported that their children did not sleep under mosquito nets the night before the survey; 67.1% of mothers reported that their children had signs of fever 30 days preceding the survey. The study found that 42.0% of the children were stunted, and 11.3% were underweight.

In terms of parental characteristics, the study found that 15.3% of the mothers had no formal education, 68.1% had a primary education and 16.6% had a secondary education. Seventy-five per cent (n = 392) of the mothers reported that they experienced IPV perpetrated by their current or most recent partner in the past 12 months. Regarding age, 7.5% of the mothers were 15 to 19 years old, 57.3% were 30 to 39 years old, 29.6% were 30 to 39 years old, and 5.5% were 40 to 49 years old. The results show that 88.7% (n = 464) of the mothers reported that they had received childcare counselling during their pregnancy. With respect to the fathers, the study found that 14.5% (n = 76) had no formal education, 56.2% (n = 296) had a primary education, and 28.7% (n = 150) had a secondary education. Slightly fewer than half of the husbands (43%) were beer drinkers and a quarter (26%) were tobacco smokers.

The study found that 11.3% (n = 59) of the households had pigs and 22.4% (n = 117) had goats in kraals/sheds close to their dwelling. Regarding house construction materials, 25.8% (n = 135) of the children lived in brick-walled houses, and only 12.8% (n = 67) lived in iron-roofed houses.

The study found that 35% of children (n = 185) were diagnosed with the malaria parasite within 48 h prior to the research interview. There was no gender difference in malaria cases among the sampled children (χ2 = 0.00, df = 1, p = 0.987). Unadjusted logistic regressions (Table 2) indicated that children of mothers who had no formal education were more likely to be diagnosed with the malaria parasite than children of mothers with a secondary school education (crude odds ratio (COR): 2.92, 95% CI 1.44–5.91, P = 0.003). Children who were in the age range of 2 to 5 and 6 to 11 months were less likely to be diagnosed with malaria compared to children who were in the age range of 24 to 59 months (COR: 0.14, 95% CI 0.07–0.26, P = 0.000 and COR: 0.26, 95% CI 0.16–0.44, P = 0.000, respectively). Children whose mothers experienced IPV in the form of controlling behaviour in the past 12 months were more likely to be diagnosed with the malaria parasite than children whose mother did not (COR: 2.92, 95% CI 1.44–5.91, P = 0.003). Children who were consistently sleeping under mosquito nets were less likely to be diagnosed with the malaria parasite than children who were not regularly sleeping under the net (COR: 0.45, 95% CI 0.30–0.75, P = 0.001). Children who did not receive de-worming drugs were more likely to be diagnosed with the malaria parasite than children who were de-wormed (COR: 2.61, 95% CI 1.79–3.82, P = 0.000). Children whose mothers had female confidants were less likely to be diagnosed with the malaria parasite than children whose mothers had no confidant (COR: 0.64, 95% CI 0.43–0.99, P = 0.048). Children whose fathers were in the age range of 15 to 24 years old were less likely to suffer from malaria than children whose fathers were in the age range of 35 to 49 (COR: 0.55, 95% CI 0.33–0.91, P = 0.021). Finally, children whose mothers were in the age range of 30 to 39 years old were less likely to suffer from malaria than children whose mothers were 40 to 49 years old (COR: 0.14, 95% CI 0.07–0.26, P = 0.000).

In multivariable analysis (Table 2), the odds of children being diagnosed with malaria was higher among children whose mothers had no formal education than among children whose mothers had a secondary education (AOR: 2.77, 95% CI 1.24–6.19, P = 0.013). It was also found that children whose mothers had experienced IPV in the form of controlling behaviour in the past 12 months had higher odds of being diagnosed with the malaria parasite compared to children whose mothers did not experience IPV in the past year (AOR: 1.88, 95% CI 1.19–2.97, P = 0.007). Children who were 2 to 5 and 6 to 11 months old were less likely to suffer from malaria than children who were 24 to 59 months old (AOR: 0.21, 95% CI 0.10–0.46, P = 0.000 and AOR: 0.43, 95% CI 0.22–0.85, P = 0.016, respectively). Finally, children of mothers who were 30 to 39 years old were less likely to be diagnosed with the malaria parasite than children whose mothers were 40 to 49 years old (AOR: 0.29, 95% CI 0.10–0.90, P = 0.032).

The results of the study demonstrate that malaria infection among children under 5 is an important public health problem in rural areas of the Dowa district. To address the problem, it is imperative that in addition to the available interventions such as LLINs and sulfadoxine-pyrimethamine preventive treatment programmes, health planners should also consider developing malaria control programmes that accommodate mothers without formal education. For example, the community-based, peer-to-peer, malaria education model has been an effective tool for behavioural changes in selected rural areas of southern Malawi, and may be applicable [42, 43].

The study also suggest that malaria control programmes in Dowa district should incorporate interventions that address IPV against mothers of young children. The current malaria proactive programmes in the Dowa district are gendered as they mainly target mothers by providing them with ITNs and by administering anti-malarial drugs during pregnancy. There is a need to involve fathers in all programmes that address child malaria. One such intervention could be a community-based participatory child malaria programmes that involve both men and women, as this has been found to improve fathers’ participation in childcare activities in similar contexts [44].

Finally, health professionals should consider engaging parents to find health promotion strategies that can reduce the risk of malaria among children 2 to 5 years old. The interventions should consider the developmental stages of children, geographical space, and the times of day and night that predispose these children to malarial vectors. For example, application of mosquito repellents can protect children from mosquito bites both indoors and outdoors. However, because current evidence on the effectiveness of repellents in the prevention of malaria in developing contexts is inconclusive, more research is needed before this intervention is adopted [45‐47].

The main strength of this study is that it is based on a systematic sampling technique and therefore, the findings can be generalized to all children 2 to 59 months old who accessed primary health care services in the studied clinics. Nevertheless, this study has some limitations. First, the study was conducted during the dry season, a period with significantly fewer mosquito-breeding sites compared to the wet season. Therefore, the findings do not represent seasonal variations in malaria prevalence. A suggestion is made that a longitudinal study should be conducted in order to provide a broader picture of malaria infection prevalence and risk factors in the study area. This study also used a cross-sectional design and as such, no causal inference can be made regarding the identified determinants and child malaria infection. Despite these limitations, the study has identified potential risk factors for malaria infection among children under 5 in rural areas of the Dowa district that can inform local programmes.