Venom composition of the Iberian adder (Vipera seoanei) from northern Portugal reveals limited sex and size variation

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  Venom composition of the Iberian adder (Vipera seoanei) from northern Portugal reveals limited sex and size variation Abstract Snake venom is a complex and dynamic ecological trait, with high potential for intraspecific variation. In this study, the venom composition of the Iberian adder ( Vipera seoanei ) from the Peneda Mountains of northern Portugal was investigated to explore whether venom varies with body size and sex. Venom proteomes from six individuals representing juvenile, subadult, and adult males and females were characterised using LC–MS/MS, while individual variation was assessed from SDS–PAGE profiles of 18 snakes. LC–MS/MS identified 144 proteins, dominated by phospholipases A 2 (PLA 2 ), snake venom serine proteases (svSP), and C-type lectin-related proteins (CTL). Descriptive comparisons revealed contrasting individual profiles, particularly between the juvenile male, characterised by high svSP and svMP abundance, and the juvenile female, characterised by high ...

Carpet Viper (Echis romani) Envenoming in Nigeria: Ecology, Venom Pathophysiology, Clinical Burden and Health-System Determinants

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Echis romani Trape, 2018 observed in South Sudan by flint_jack (licensed under CC BY-NC 4.0)


Carpet Viper (Echis romani) Envenoming in Nigeria: Ecology, Venom Pathophysiology, Clinical Burden and Health-System Determinants

Abstract

Purpose of review

The carpet viper (Echis romani, recently separated from E. ocellatus) accounts for at least 66% of confirmed snakebite envenomings in the Nigerian savanna. Despite this, continental hazard modeling ranks it second in Nigeria. It is smaller and not necessarily more venomous per bite than the puff adder (Bitis arietans) or the black-necked spitting cobra (Naja nigricollis). This review synthesizes evidence on the ecology, venom effects, clinical impact, and health-system factors of carpet viper envenoming in Nigeria, including its effects on livestock and One Health considerations.

Recent findings

The risk of snakebite is influenced by multiple factors beyond venom potency alone. Carpet vipers are common in farmland and rural areas, where farmers, herders, and children are at risk. Their camouflage and defensive strikes increase the chances of accidental bites. Their metalloproteinase-rich venom can cause coagulopathy, bleeding, tissue damage, shock, and death if left untreated. While case fatality has decreased to approximately 1.4–1.5% at specialized centres with effective antivenom, this progress is fragile due to delayed presentation, limited rural healthcare, and inconsistent antivenom availability. Evidence regarding livestock is limited; although animals share the habitat, bites are rarely documented. Promising small-molecule toxin inhibitors are not yet validated for E. romani. Climate and land-use models suggest habitat changes may alter snake distribution.

Summary

Carpet viper envenoming is a major and preventable cause of snakebite morbidity and mortality in northern Nigeria. Current evidence supports sustained investment in antivenom supply, rural diagnostic capacity (including the 20-minute whole-blood clotting test), referral pathways, community prevention, rehabilitation and standardized, species-confirmed surveillance.

Michael, G.C., Bala, A.A. Carpet Viper (Echis romani) Envenoming in Nigeria: Ecology, Venom Pathophysiology, Clinical Burden and Health-System Determinants. Curr Trop Med Rep 13, 22 (2026). https://doi.org/10.1007/s40475-026-00380-8