Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production

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  Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production Abstract Variability in the antibody response of horses used for snake antivenom manufacture is well recognized, yet its statistical structure and implications for industrial productivity remain poorly characterized. In this study, we quantified antivenom antibody titers by ELISA in a cohort of 14 horses immunized with venoms from the clinically most important snakes in sub-Saharan Africa. To integrate antibody levels with plasma availability, we calculated the Cumulative Plasma Productivity (CPP) by converting individual plasma volumes into titer-corrected equivalents and sequentially pooling these volumes according to their corrected contribution. Distributional analysis revealed right-skewed, heavy-tailed patterns better approximated by a log-normal model than by a strict Pareto (power-law) form, with approximately 20–3...

Determinants of severity and spatial inequalities in snakebite envenomation in a vulnerable Brazilian mesoregion: a retrospective ecological study

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Determinants of severity and spatial inequalities in snakebite envenomation in a vulnerable Brazilian mesoregion: a retrospective ecological study

Abstract

Introduction

Snakebite envenomation is a neglected tropical disease with a significant impact on public health, especially in socially vulnerable regions. Our objective was to describe the clinical and epidemiological profile of cases and identify factors associated with severity in a Brazilian mesoregion.

Methods

A retrospective ecological study was conducted using secondary data from the Notifiable Diseases Information System, including all reported cases of snakebite envenomation between 2014 and 2024. Sociodemographic, clinical, and healthcare-related variables were analyzed. Severity was classified as mild, moderate, or severe according to national guidelines. Multinomial logistic regression was performed to assess factors associated with severity. Missing data were handled using multiple imputation by chained equations.

Results

1,272 cases were recorded, corresponding to an incidence of 346.87 cases per 100,000 inhabitants. Most cases occurred in males (69.5%), individuals aged 20–59 years (60.1%), and were caused by Bothrops species (75.9%). Mild cases predominated (49.8%), followed by moderate (41.6%) and severe cases (7.0%), with an overall case lethality rate of 8.8%. Time to treatment between 3 and 6 h was associated with a higher relative risk of moderate severity (RRR = 1.48; p = 0.029). Significant territorial differences were observed, with some municipalities showing substantially higher relative risks of severe classification.

Conclusions

Snakebite envenomation in this mesoregion represents a relevant public health issue, marked by regional inequalities in severity and outcomes. Factors related to healthcare access, geographic location, and clinical characteristics were associated with severity. These findings highlight the need to strengthen health systems, improve access to timely treatment, and implement targeted prevention strategies in vulnerable areas.

Tolentino Júnior, D.S., da Silva, L.A., Brunelli, L.F. et al. Determinants of severity and spatial inequalities in snakebite envenomation in a vulnerable Brazilian mesoregion: a retrospective ecological study. Discov Public Health 23, 661 (2026). https://doi.org/10.1186/s12982-026-01979-y