Epidemiology of Lassa fever outbreaks in Edo State, Nigeria, 2017-2023: A retrospective analysis
5 affiliations
- 1Nigeria Field Epidemiology and Laboratory Training Programme (NFELTP), Abuja, Nigeria
- 2Ministry of Health, Benin City, Edo State, Nigeria
- 3Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
- 4Veterinary Epidemiology and Vector Control Unit, Ministry of Agriculture and Food Security, Benin City, Edo State
- 5World Health Organization, Benin City, Edo State, Nigeria
Abstract
Introduction: Lassa fever (LF) is an epidemic-prone disease with outbreaks following a seasonal pattern across the endemic countries in West Africa. We carried out a retrospective analysis of Lassa fever outbreaks in Edo State, Nigeria, to describe their epidemiological patterns. Methods: A retrospective descriptive study was conducted using secondary surveillance data from LF outbreaks reported to the Edo State Ministry of Health from January to April of each year, 2017 through 2023. Data collection was done through data extraction from the database of the Edo State Public Health Emergency Operation Centre using a data extraction form. Analyses were based on laboratory-confirmed LF cases. Cumulative incidence and case fatality rate (CFR) were calculated. Categorical variables were summarized in frequencies and proportions, while continuous variables were summarized using appropriate measures of central tendency and dispersion. Results: A total of 9,003 suspected LF cases were reported, of which 1,361 (15.1%) were laboratory-confirmed. The median age of confirmed cases was 28 (interquartile range: 18-40) years; 770 (56.6%) were male, and 331 (24.3%) were aged 21–30 years. Among the 883 confirmed cases with occupation data available from 2018 through 2023, 383 (43.4%) were students. The highest reported case counts generally occurred between epidemiological weeks 1 and 11. Etsako West, Esan West and Esan North-East accounted for 431 (31.7%), 361 (26.5%), and 248 (18.2%) confirmed cases, respectively. Overall CFR was 12.6% (171/1,361). During the January-April 2020 outbreak period, cumulative incidence was highest in Esan West (53.4 per 100,000 population), followed by Esan North-East (45.4 per 100,000) and Etsako West (35.0 per 100,000). Conclusion: Esan West, Etsako West, and Esan North-East accounted for a substantial proportion of the reported LF burden during the study period. The findings highlight the importance of geographically targeted and timely public health preparedness and response efforts ahead of LF outbreak periods. Preparedness efforts should prioritize strengthened surveillance activities in areas with recurrently high reported LF burden to reduce morbidity and mortality.
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BibTeX
@article{okhuarobo2026epidemiology,
title = {{Epidemiology of Lassa fever outbreaks in Edo State, Nigeria, 2017-2023: A retrospective analysis}},
author = {Uwaifiokun Julius Okhuarobo and Stephenson Babatunde Ojeifo and Mercy Onize Okuo and Armstrong Hamisu Waziri-Atebor and Denyinye Minna Hitlar and Osahogie Isaac Edeawe and James Adebayo Igenoza and Grace Folusho Ireotoi and Nora Emmanuel Eyo and Ekaete Alice Tobin},
journal = {Journal of Interventional Epidemiology and Public Health},
year = {2026},
month = oct,
doi = {10.37432/jieph-d-26-00095},
url = {https://doi.org/10.37432/jieph-d-26-00095},
note = {CC BY},
}
RIS
TY - JOUR
TI - Epidemiology of Lassa fever outbreaks in Edo State, Nigeria, 2017-2023: A retrospective analysis
AU - Uwaifiokun Julius Okhuarobo
AU - Stephenson Babatunde Ojeifo
AU - Mercy Onize Okuo
AU - Armstrong Hamisu Waziri-Atebor
AU - Denyinye Minna Hitlar
AU - Osahogie Isaac Edeawe
AU - James Adebayo Igenoza
AU - Grace Folusho Ireotoi
AU - Nora Emmanuel Eyo
AU - Ekaete Alice Tobin
PY - 2026
DA - 2026/10/01
JO - Journal of Interventional Epidemiology and Public Health
DO - 10.37432/jieph-d-26-00095
UR - https://doi.org/10.37432/jieph-d-26-00095
AB - Introduction: Lassa fever (LF) is an epidemic-prone disease with outbreaks following a seasonal pattern across the endemic countries in West Africa. We carried out a retrospective analysis of Lassa fever outbreaks in Edo State, Nigeria, to describe their epidemiological patterns. Methods: A retrospective descriptive study was conducted using secondary surveillance data from LF outbreaks reported to the Edo State Ministry of Health from January to April of each year, 2017 through 2023. Data collection was done through data extraction from the database of the Edo State Public Health Emergency Operation Centre using a data extraction form. Analyses were based on laboratory-confirmed LF cases. Cumulative incidence and case fatality rate (CFR) were calculated. Categorical variables were summarized in frequencies and proportions, while continuous variables were summarized using appropriate measures of central tendency and dispersion. Results: A total of 9,003 suspected LF cases were reported, of which 1,361 (15.1%) were laboratory-confirmed. The median age of confirmed cases was 28 (interquartile range: 18-40) years; 770 (56.6%) were male, and 331 (24.3%) were aged 21–30 years. Among the 883 confirmed cases with occupation data available from 2018 through 2023, 383 (43.4%) were students. The highest reported case counts generally occurred between epidemiological weeks 1 and 11. Etsako West, Esan West and Esan North-East accounted for 431 (31.7%), 361 (26.5%), and 248 (18.2%) confirmed cases, respectively. Overall CFR was 12.6% (171/1,361). During the January-April 2020 outbreak period, cumulative incidence was highest in Esan West (53.4 per 100,000 population), followed by Esan North-East (45.4 per 100,000) and Etsako West (35.0 per 100,000). Conclusion: Esan West, Etsako West, and Esan North-East accounted for a substantial proportion of the reported LF burden during the study period. The findings highlight the importance of geographically targeted and timely public health preparedness and response efforts ahead of LF outbreak periods. Preparedness efforts should prioritize strengthened surveillance activities in areas with recurrently high reported LF burden to reduce morbidity and mortality.
SN - 2664-2824
ER -