Sero-prevalence, risk factor and force of infection estimates for foot-and-mouth disease in two cattle rearing areas of Cameroon

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Foot-and-mouth disease (FMD) continues to be a major global disease, directly impacting endemic regions and indirectly affecting FMD-free regions. Reliable estimates of key epidemiological parameters, such as transmission rates, from empirical field data are scarce yet essential for developing statistical and mathematical models to assess control strategies and inform policy. Here, we estimate the seroprevalence and risk factors for FMD across the North-West Region (NWR) and Vina Division (VIN) of Cameroon and use these data to estimate the force of infection and the reproductive numbers, R 0 and R t . A total of 1,498 cattle from 100 herds across the Northwest Region and Vina Division of Cameroon were sampled. Evidence of recent FMD occurrence was widespread, with 60.1% of herdsmen in the NWR and 76.8% in the VIN reporting clinical FMD within the previous 12 months. FMD non-structural protein (NSP) antibody responses increased with age before reaching a plateau, consistent with cumulative exposure in endemic settings. Using an empirically derived ELISA cutoff (>40 PI), the design-adjusted animal-level seroprevalence was 38.2% [95% confidence intervals (CI): 31.3–45.8] in the NWR and 56.7% (95% CI: 47.8–65.2) in the VIN, demonstrating substantial virus circulation in both regions and significantly greater exposure in the VIN. Age-stratified analyses revealed a rapid increase in seroprevalence during the first 4–5 years of life, with force of infection estimates almost two-fold higher in the VIN ( λ = 0.382) than in the NWR ( λ = 0.197). Correspondingly, the basic reproduction number (R₀) was estimated at 3.04 (95% CI: 2.84–3.26) in the VIN and 2.05 (95% CI: 1.93–2.18) in the NWR. After accounting for population immunity and test performance, the effective reproductive numbers (Rt) were 1.14 (95% CI: 1.02–1.22) and 1.23 (95% CI: 1.15–1.30), respectively for the VIN and NWR. Foot-and-mouth disease is endemic in both study regions of Cameroon, with evidence of substantial transmission and cumulative exposure occurring early in life. Despite the lack of serotype-specific data, age-stratified serology provided robust estimates of population-level transmission, highlighting marked regional variation, the complexity of estimating epidemiological parameters in endemic settings, and the need to further explore the factors driving local disease dynamics.