Malaria in children under-five: A comparison of risk factors in lakeshore and highland areas, Zomba district, Malawi

Background
In Malawi, children under the age of five living in different geographical areas may experience different malaria risk factors. We compare the risk factors of malaria experienced by children under the age of five from Zomba district, who reside in lakeshore and highland areas.
Methods
We conducted a case control study of 765 caregivers, cases being children under-five who were diagnosed with malaria, and obtained matched controls from local health facilities and communities. We used a multivariate logistic regression to identify individual and household risk factors.
Results
In lakeshore areas, risk factors were households located one kilometer or less away from stagnant water (AOR: 2.246 95% CI: 1.269 to 3.975 P-value: 0.005); or if the household had obtained a mosquito bed net more than one year ago (AOR: 1.946 95% CI: 1.073 to 3.529 P-value: 0.028). In highland areas, risk factors were households which used a borehole/unprotected well (AOR: 1.962 95% CI: 1.001 to 3.844 P-value 0.050), communal standpipe (AOR: 3.293 95% CI: 1.301 to 8.332 P-value 0.012), and un-protected dug well in their yards (AOR: 16.195 95% CI: 2.585 to 101.464 P-value 0.003) as their drinking water sources. In highland areas, caregivers not attending health talks on malaria prevention messages was a risk factor (AOR: 2.518 95% CI: 1.439 to 4.406 P-value: 0.001).
Conclusion
Children under the age of five living in highland areas experience different malaria risk factors compared to children living in lakeshore areas. Settling away from stagnant/open water source in lakeshore and encouraging caregivers to attend health talks on malaria prevention in highlands can help reduce malaria transmission. Nevertheless, using a mosquito bed net that is more than one year old is a common risk factor in both locations. Using new mosquito bed nets can significantly reduce the risk of contracting malaria in children under the age of five.

研究背景
在马拉维，不同地理区域居住的五岁以下儿童所面临的疟疾危险因素存在差异。本研究针对松巴（Zomba）区湖滨与高地两类区域的五岁以下儿童，对比分析其各自罹患疟疾的危险因素。

研究方法
本研究纳入765名儿童看护者开展病例对照研究：病例组为经确诊的疟疾五岁以下儿童，对照组则从当地医疗卫生机构与社区中选取匹配对照。本研究采用多因素logistic回归分析，以识别个体及家庭层面的疟疾危险因素。

研究结果
在湖滨区域，疟疾危险因素包括：住所距离积水区域≤1公里（校正优势比（Adjusted Odds Ratio，AOR）=2.246，95%置信区间（Confidence Interval，CI）：1.269~3.975，P值=0.005）；以及家庭使用的蚊帐使用时长超过1年（AOR=1.946，95%CI：1.073~3.529，P值=0.028）。
在高地区域，疟疾危险因素包括：以钻孔水井/无保护水井作为饮用水源（AOR=1.962，95%CI：1.001~3.844，P值=0.050）、以公共供水柱作为饮用水源（AOR=3.293，95%CI：1.301~8.332，P值=0.012），以及家庭院落内使用未加防护的挖掘井作为饮用水源（AOR=16.195，95%CI：2.585~101.464，P值=0.003）。此外，高地区域中未参与疟疾预防健康宣讲的看护者，其看护的儿童罹患疟疾的风险显著升高（AOR=2.518，95%CI：1.439~4.406，P值=0.001）。

研究结论
与湖滨区域的五岁以下儿童相比，高地区域的五岁以下儿童所面临的疟疾危险因素存在显著差异。在湖滨区域，引导居民远离积水区域定居；在高地区域，鼓励看护者参与疟疾预防健康宣讲，均有助于降低疟疾传播风险。值得注意的是，使用时长超过1年的蚊帐是两类区域共同的危险因素。及时更换新蚊帐，可显著降低五岁以下儿童的疟疾感染风险。