By Ifham Nizam

Peradeniya University scientists are awaiting the Health Ministry’s go-ahead to launch the first locally manufactured anti-serum to treat snakes bites.

The University’s Head Professor, Faculty of Veterinary Pathobiology, R. P. V. J. Rajapakse, said that half a dose of the locally produced serum was sufficient to treat snake bite victims

“The preclinical tests have been completed and the level of efficacy was excellent,” he said.

He said an imported dose costs eight US dollars, whereas the local product can be made available at a more competitive price.

Russell’s viper (Daboia russelii), common Krait (Bungarus caeruleus), Hump-nosed viper (Hypnale hypnale), Cobra (Naja naja), Saw-scaled viper (Echis carinatus) and Ceylon krait (Bungarus ceylonicus) are snakes considered “medically important” in Sri Lanka.

The most common bite is Hump-nosed viper and Ceylon krait, which are highly venomous and found only is Sri Lanka, he said.

“Usually, we import anti-serum from India. However, as they produce antivenin using Indian snakes, the toxicity and composition vary from Sri Lankan snake species venom as the Krait and Hump-nosed Viper species are not found there”, he explained.

“Therefore we decided to develop antivenin compatible with our ‘medically important’ snakes in collaboration with an Indian, WHO recommended laboratory”, he noted.

Prof. Rajapakse said that Sri Lanka can even export antivenin to other countries if a WHO recommended bio-safe plant was established under a substantial investment.

The local anti-serum was developed by the Peradeniya University under the guidance of Prof. S. A. M. Kularatne, Senior Professor of Medicine and Senior Scientist Anslem de Silva in collaboration with the Department of Wildlife Conservation, Ministry of Science and Technology.

The government spends around Rs. 1 billion to import anti-venom serum from India, but experts have pointed out that the potency of the venom, particularly when it comes to Russell’s Viper and Hump-nosed Viper in Sri Lanka are more toxic than in India.

Medical experts say that a victim with serious bites suffer acute kidney damage and many other complications when it comes to the hypnale species.

Professors S. A. M. Kularatne, Kolitha Sellahewa, Ariyarani Ariyaratnam, Kalana Maduwage and Dr. Namal Ratnayake from the Teaching Hospital, Ratnapura, have managed several hundred cases of hypnale.

A decade ago, snake bites were a major problem with some 60,000 people falling victim annually. Only around 40,000 of the victims received treatment from hospitals, while the others resorted to traditional native snake bite treatment.

In total, 97% of snake bite deaths are caused by the cobra, Russell’s Viper and Common India Krait. Apart from them, the Sri Lankan Krait and Saw Scaled Viper are categorized as a dangerous species though they have not caused many deaths. The Merrem’s Hump-nosed Viper is considered by the Sri Lanka Medical Association as a deadly species.

However, of the land snakes only a few are ‘medically important’ or can inflict a bite, where the venom could be mild, moderate or highly venomous. It is of interest to note that to date, modern medical literature record human fatalities only due to four species of snakes – Russell’s Viper, Cobra, Kraits and the Hump-nosed Viper.

The Hump-nosed Pit Viper (Hypnale Merrem’s pit viper) is a snake widely distributed in Sri Lanka and the South Western coastal region of India.

It is the most common snake responsible for venomous snakebites in Sri Lanka, estimated to be between 22% to 77% of all snakebites (de Silva, 1981; Seneviratne, 2000). For centuries, it was considered a relatively innocuous snake until 1821, when for the first time, swelling and bleeding due to bites by H. hypnale was reported in animals (Davy, 1821)