Epidemiology and clinical effects of hump-nosed pit viper (Genus: Hypnale) envenoming in Sri Lanka

► Definite bites by all three Hypnale species (hump-nosed viper) in Sri Lanka caused similar clinical effects. ► Pain, fang marks and local swelling were common but only 14% had extensive local injury requiring treatment. ► Systemic effects were rare with only 3% having an abnormal clotting test and one developing renal failure. ► The majority of hump-nosed viper bites cause minor effects.