Malaria Outbreak Investigation in Argoba District, South Wello Zone, Northeast Ethiopia, 2016: A case control study

Abstract Background Malaria remains a major global public health concern and approximately half of the world’s population being at risk of infection. It is one of the common epidemic prone diseases and can result in continuous epidemics and end up with serious public health emergencies. Therefore, this study aimed at identifying determinants of malaria outbreak in Argoba district. Methods Community based case-control study was employed with a 1:1 case to control ratio at Argoba district from 21 June to 7 July, 2016. A total of 150 individuals (75 cases and 75 controls) were included in the study. Cases were taken from treatment registration book and neighborhoods to the cases were taken as control groups. Structured questionnaire was used as data collection tool. Data was entered using Epi-info version 7 statistical software and exported to STATA version 14 for analysis. A multivariable logistic regression analysis was used to identify determinants of the outbreak. The magnitude of the outbreak was described by place, person, and time. Adjusted Odds Ratios (AOR) with the corresponding 95% Confidence Interval (CI) was used to show the strength of associations and variables with P-values of <0.05 were considered statistically significant. Results The predominant Plasmodium species detected was P.falciparum, which is followed by P.vivax. The overall attack rate was 1.8%. Travel history to malarias site (AOR=14.6: 95% CI: 2.8, 77.7) and presence of mosquito breeding site around the home (less than 1000 meter) (AOR=13.3: 95% CI: 3.1, 58.0) were associated with the occurrence of malaria outbreak. However, using insecticide treated bed nets (AOR=0.004; 95% CI: 0.001, 0.06) and chemical indoor residual spray (AOR=0.02; 95% CI: 0.01, 0.09) were found to be protective factors. Conclusions malaria outbreak was affected by distance from the breeding site and traveling history of malaria endemic areas. In contrast, bed net utilization and house hold spray with DDT were preventive factors of the outbreak. It is recommended to use bed net utilization and house hold spraying in the district.