BACKGROUND:
Since 2013, Ethiopia has seen a notable rise in dengue cases. In July 2023, a suspected outbreak began in Metahara town, Oromia Regional State. This study aimed to confirm the outbreak, identify associated risk factors, and guide control efforts.

METHODS:
We performed a descriptive study combined with an unmatched case-control design using a 1:2 case-to-control ratio. Data collection involved line lists, laboratory test results, environmental assessments, home visits, and entomological surveys. Fifty cases were randomly selected from the line list, while 100 controls were purposively chosen from the same neighbourhood. A total of 150 participants were interviewed face-to-face using a community-based approach. Data were collected with Kobo Collect and analyzed using SPSS version 26, with summaries prepared in Microsoft Excel 2013. Variables with p-values ≤ 0.25 in the bivariate analysis were included in a multivariate binary logistic regression model. Associations were measured by crude and adjusted odds ratios (OR and AOR), considering p ≤ 0.05 as statistically significant.

RESULTS:
The outbreak was confirmed with 342 dengue cases, yielding an attack rate of 7.1 per 1,000 and a case fatality rate of 0.88%. Significant risk factors included not using long-lasting insecticide-treated nets during daytime (adjusted OR 9), presence of open water containers at home (adjusted OR 5), and lack of disease awareness (adjusted OR 25). Wearing long-sleeved clothing reduced infection risk by 75%.

CONCLUSIONS:
The Metahara dengue outbreak was driven by Aedes aegypti mosquitoes, ongoing circulation of DENV-3, and weak vector control measures. Critical issues were poor use of insecticide-treated nets, improper water storage, low community awareness, and insufficient protective clothing. Recommended actions include strengthened vector control, community education, promotion of protective clothing, and enhanced disease surveillance.