[COLOMBO] Sri Lankan and Australian scientists have developed a test to quickly determine whether snakebite victims need to be treated with anti-venom — which can trigger severe and sometimes fatal allergic reactions in patients.

Administration of anti-venom, the main treatment for snakebites, is typically delayed until the victim develops symptoms of venom in the blood. But this could vary from a few minutes to several days during which time the victim could suffer irreversible nerve damage or die.

The new test, developed by researchers at the University of Peradeniya, Sri Lanka, and the University of Newcastle, Australia looks for the presence of an enzyme called Phospholipase A2 (PLA2), which occurs in the venom of most snake species and shows up in the bloodstream of snakebite victims.

By measuring the levels of PLA2 in the blood it is possible to gauge the severity of the envenoming which is valuable in planning treatment.

According to Geoffrey K. Isbister, professor at the University of Newcastle and leader of the research published in Scientific Reports in April, existing tests are not reliable and differ with snake species. Thus, blood-clotting tests, which work with Russel’s viper, are unsuitable for the Indian cobra or the krait.

“We have already shown that the new test works for all Sri Lankan snakes and one lot of Australian snakes; however the test can potentially be used for most venomous snakes worldwide because we are testing for PLA2, which occurs in most snake venoms,” Isbister tells SciDev.Net.

The test cannot determine the snake species responsible for envenoming, but that is not a drawback as most anti-venom are polyvalent and can be used to treat the bite of several species of venomous snakes, says Kalana Maduwage, scientist at the biochemistry department at the University of Peradeniya.

“A test indicating whether the patient has snake envenoming is sufficient for polyvalent anti-venom to be administered,” Maduwage explains to SciDev.Net. 

“If the new research could be developed into bedside test, it will certainly improve the management of snakebite victims,” says S.A.M. Kularatne, head of an expert committee on snakebites set up by the Sri Lanka Medical Association.

Kularatne adds that snakebites are a neglected problem in Sri Lanka and elsewhere because the victims are usually poor people living in rural areas.

A recent WHO study estimates that at least 421,000 envenoming cases and 20,000 deaths occur worldwide from snakebites each year, though the figures may be as high as 1,841,000 envenoming and 94,000 deaths.

South Asia, Southeast Asia, and Sub-Saharan Africa record the highest number of venomous snakebites with remote parts of these regions having limited access to anti-venom.

> Link to article in Scientific Reports

This article has been produced by SciDev.Net’s South Asia desk.