Factors associated with a malaria outbreak at Tongogara Refugee Camp in Chipinge District, Zimbabwe, 2021: A case-control study

Abstract

BackgroundMalaria is a leading cause of morbidity and mortality among forcibly displaced populations including refugees, approximately two-thirds of whom reside in malaria endemic regions. Data from the rapid disease notification system (RDNS) reports for Manicaland Province in Zimbabwe showed that despite implementation of malaria control initiatives, there was an increase in number of malaria cases above action thresholds at Tongogara Refugee Camp in Chipinge District during weeks 12-14. We investigated the malaria outbreak describing the outbreak by person, place and time, assessing malaria emergency preparedness and response and appropriateness of case management. We also determined the factors associated with contracting malaria to enable the formulation of appropriate interventions, establish control and prevent future malaria outbreaks among this vulnerable population.MethodsWe conducted a 1:1 unmatched case control study involving 80 cases and 80 controls using interviewer-administered questionnaires at household level. Data was entered using Epi Data version 3.1 and analyzed using Epi InfoTM version 7.2.4 to generate medians, proportions, odds ratios and their 95% confidence intervals.ResultsMalaria cases were distributed throughout the 10 residential sections within Tongogara Refugee Camp, the majority being from section 7, 28/80 (35%). Despite constituting 11% of the total population, Mozambican nationals accounted for 36/80 (45%) cases. Males constituted 47/80 (59%) among cases versus controls 43/80 (54%), p=0.524. Median age for cases was also lower compared to controls; 15 years [Interquartile range (IQR), 9-26] versus 17 years (IQR, 10-30). Several natural and manmade potential vector breeding sites were observed around the camp. Risk factors associated with contracting malaria were engaging in outdoor activities at night [AOR 4.26 (95% CI, 1.43-12.68)], wearing clothes that do not cover the whole body [AOR=2.74 (95% CI 1.04-7.22) while sleeping in a refugee housing unit reduced the risk of contracting malaria [AOR=0.18 (CI, 0.06-0.55)]. ConclusionsThe malaria outbreak at Tongogara Refugee Camp reemphasizes the role of behavioral factors in malaria transmission. We recommend intensified health education to address human behaviors that expose residents to malaria and habitat modification with larviciding to eliminate mosquito breeding sites.