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Open Access Short Report

Comparative in-vivo toxicity of venoms from South Asian hump-nosed pit vipers (Viperidae: Crotalinae: Hypnale)

Anjana Silva1*, Panduka Gunawardena2, Danister Weilgama3, Kalana Maduwage4 and Indika Gawarammana5

Author Affiliations

1 Department of Parasitology, Faculty of Medicine and Allied Sciences Rajarata, University of Sri Lanka, Saliyapura, Sri Lanka

2 Department of Veterinary Pathobiology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya, Sri Lanka

3 Department of Parasitology, Faculty of Medicine and Allied Sciences Rajarata, University of Sri Lanka, Saliyapura, Sri Lanka

4 School of Medicine and Public Health, University of Newcastle, NSW, Australia

5 Department of Medicine, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka

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BMC Research Notes 2012, 5:471  doi:10.1186/1756-0500-5-471

Published: 29 August 2012

Abstract

Background

Envenoming by south Asian hump-nosed pit vipers (Genus: Hypnale) is a significant health issue in Sri Lanka and in peninsular India. Bites by these snakes frequently lead to local envenoming, coagulopathy and acute renal failure even resulting in death. Recently the genus was revised and the existence of three species viz H. hypnale, H. nepa and H. zara were recognized. There is, however, a paucity of information on the toxicity of the venoms of these species. Hence, we compared the toxic effects of the three Hypnale venoms using BALB/c mice.

Findings

Intraperitoneal median lethal doses (LD50) for H. hypnale, H. zara and H. nepa venoms were 1.6, 6.0 and 9.5 μg protein/g respectively. Minimum haemorrhagic doses for venoms of H. hypnale, H. zara and H. nepa were 3.4, 11.0 and 16.6 μg protein/mouse respectively. The minimum necrotic doses for the same venoms were 15.0, 55.1 and 68.2 μg protein/mouse respectively. Severe congestion and petecheal haemorrhages were observed in lungs, kidneys, liver and the alimentary tract. Histopathogical examination of kidneys revealed proximal tubular cell injury and acute tubular necrosis with intact basement membrane indicating possible direct nephrotoxicity. Hypnale venoms caused pulmonary oedema, hepatocellular degeneration and necrosis, focal neuronal degeneration in brain and extramedullary haemopoiesis in spleen. H. hypnale venom caused all above histopathological alterations at lower doses compared to the other two.

Conclusion

Hypnale venoms cause similar pathological changes with marked differences in the severity of the toxic effects in vivo. Therefore, differences in the severity of the clinical manifestations could possibly be seen among bite victims of the three Hypnale species.

Keywords:
Hypnale; Nepa; Zara; Venom; Toxicity; Histopathology