Outbreak Volatility and High Lethality: A Comparative Burden Analysis of Cholera and Lassa Fever in Nigeria (2019–2024) with Policy, Preparedness and Resource Implications

Background Despite the fact that Lassa fever and cholera are two of Nigeria's most deadly epidemic-prone diseases, few studies have examined their combined burden to aid in effective preparedness planning. This research study provides a comparative examination of epidemiological trends from 2019 to 2024, with implications for health-care financing and resource allocation. Methods A retrospective analysis of surveillance data (NCDC, WHO) was conducted. Descriptive statistics, Bayesian Structural Time Series, seasonal decomposition, and change-point detection identified temporal and spatial trends. Odds ratios (ORs) assessed demographic risks, while proportional state contributions quantified geographic concentration of burden. Results Between 2019 and 2024, there were 204,329 cholera and 3,654 Lassa fever cases reported. Cholera disproportionately affected children under the age of 15 (OR = 1.71), but Lassa fever was more common in adults aged 25 to 44. Males were more affected by Lassa fever, and females by cholera. Cholera outbreaks were very variable (111,062 cases in 2021; +15,325% from 2020), demanding significant surge-response costs, whereas Lassa fever caused smaller but persistent seasonal outbreaks with a consistently high CFR of 22.1%, indicating the severe resource load of case management. Cholera was predominant in northern states (Bauchi, Borno, and Kano), whereas Lassa fever was concentrated in Ondo and Edo (66.3% of cases). Conclusion Conclusion: Nigeria is dealing with two epidemics: cholera, a climate-driven illness that spawns outbreaks, and Lassa fever, a deadly rodent-borne chronic disease. These trends impose considerable and continuous financial demands on the healthcare sector. Regionally diverse preparation, including WASH infrastructure in the north and ecological/diagnostic investments in the south, paves the way for more cost-effective epidemic management. Predictive modelling, early warning systems, and targeted funding are important to lowering the health and economic consequences of these epidemics.