THIRUVANANTHAPURAM: In the backdrop of deaths resulting from pit viper bites in Kasaragod and Idukki districts, demands are rising to develop anti-snake venom for a variety of vipers found in the state. While the vipers in question -- Anamalai pit viper (APV), hump-nosed pit viper (HNPV), Travancore pit viper and Malabar pit viper -- are not highly venomous, they come under the category of venomous snakes.
Experts claim that the recent deaths after HNPV and APV bites happened because of other ailments consequent to the snake bites. At the same time, the fact is that the current polyvalent anti-snake venom is only for the big four among snakes -- spectacled cobra, common krait, Russell’s viper and saw-scaled viper -- but not for other snakes.
Initially, the vipers found in south India were categorised into five species -- Malabar pit viper, bamboo pit viper, horse-shoe pit viper, large-scaled pit viper and hump-nosed pit viper.
Later, the Malabar pit viper was reclassified into three species -- Travancore pit viper (found in Thiruvananthapuram and Kollam), Anamalai pit viper (from Pathanamthitta to Nelliyampathy in Palakkad) and Malabar pit viper (Palakkad gap to northern Western Ghats).
While there are genetic differences, they look the same to an untrained eye. Hence, they are categorised according to the location.
Over the past few years, Kerala has been seeing a spurt in the number of deaths due to HNPV bites. On October 24, Manjeshwar resident Ashok, 43, died at a private hospital in Mangaluru following an HNPV bite. The next day, an APV bite case was reported in Kallar in Idukki. According to the Facebook group ‘Snakes of Kerala’, over the past fortnight, at least half a dozen people were fortunate to have spotted vipers in the nick of time.
According to Dr Sandeep Das, a leading herpetologist, polyvalent anti-snake venom is neither effective nor advisable in the event of a venomous or highly venomous snake bite. “When a patient bitten by a snake is taken to the hospital, the doctor there treats them symptomatically. Anti-venom is effective only for the big four in India. So, administering anti-snake venom for pit viper bites is useful but at times it can also cause anaphylaxis (a life-threatening allergic reaction). Research is on to develop anti-snake venom for pit viper bites, especially HNPV bites, and it should bear fruit in the near future,” said Dr Sandeep, a Science and Engineering Research Board national post-doctoral fellow with the Calicut University’s department of zoology.
Dr P Jayesh Kumar, professor and HOD, general medicine, Kozhikode Medical College, said if snakebite deaths were earlier caused by Russell’s viper and saw-scaled viper, now HNPV bites have taken centre stage. “We won’t give anti-snake venom for HNPV or APV bite cases, but provide supportive treatment. The symptoms shown are inflammation in the bitten area and coagulant failure. Renal failure doesn’t happen. It’s high time anti-snake venom for pit vipers is produced to save lives,” he said.
Research is on at the Indian Institute of Science, Bengaluru, on pit viper venom and probable treatment techniques. The development of anti-snake venom in Kerala would help bring down the chances of geographical variation, experts said.