Scientists devise smartphone-based test to detect venomous snakebites

The test involves a minor blood test that can not only tell if the victim was bitten by a poisonous snake within 10-15 minutes but also an approximate amount of venom in the body to help doctors fix the anti-venom dose.

New Delhi: In what may aid lakhs of snakebite victims, Indian scientists have come out with a novel diagnostic technique to determine if a person has been bitten by a venomous snake or a non-venomous one within four hours of the snakebite.

The smartphone-based method has been customised to identify the bites of the Indian cobra, Common krait, Russell's viper, Saw-scaled viper and Indian monocled cobra – the five reptiles that are responsible for the majority of snakebite-related morbidity and mortality in India.

Currently, doctors or health attendants at rural clinics depend on their experience to determine if a particular snakebite has been caused by a poisonous snake. There is no commercial kit available for such detection.

Developed by researchers at Tezpur University and the Institute of Advanced Study in Science and Technology, Guwahati, the new technique involves a minor blood test that can not only tell if the victim was bitten by a poisonous snake but also an approximate amount of venom in the body to help doctors fix the anti-venom dose.

“It takes about 10-15 minutes to get the results. The test can be carried out within four hours of a snakebite,” Ashish Kumar Mukherjee, principal investigator and director of the Guwahati Institute, told DH.

There are two types of snakebites – wet and dry. A snakebite from a venomous serpent can be classified as a 'wet bite,' which may cause minor local symptoms to severe systemic toxicity and perhaps death, or a 'dry bite,' which presents no local or systemic indications of envenomation.

A recent Million Death Study commissioned by the Registrar General of India has estimated that there are around 46,900 deaths per year due to venomous snakebites in India, though scientists are of the opinion that the magnitude may be far greater.

Indian peninsula hosts 52 deadly species of snakes, but the majority of the snakebites are caused by the Indian cobra (Naja naja), Common krait (Bungarus caeruleus), Russell’s viper (Daboia russelii russelii), and Saw-scaled viper (Echis carinatus) that are collectively referred to as the ‘Big Four.’

The test is also applicable for a fifth snake, the Indian monocled cobra (Naja kaouthia), that is common in the North East.

The detection is done using a colourimetric assay – the colour of the reagent changes from burgundy to blue. An analysis of the image taken by smartphone cameras can also reveal the quantity of venom in the body.

The scientists have filed a patent on the novel technique and are planning to develop an easy-to-use application for smartphones.

“There have been a few reports of methods for distinguishing between venomous and dry bites in India. However, the detection time was reported to be 60 minutes post-envenomation. In our method, the detection could be done even at 240 min post-envenomation,” Mukherjee said.

Their research paper describing the new method has been published in the journal PLOS Neglected Tropical Diseases.