Year : 2013 | Volume
: 6 | Issue : 2 | Page : 123--125
Snake bite envenomation: A neglected public health problem in India
Tushar B Patil
Department of Medicine, Government Medical College, Nagpur, Maharashtra, India
Tushar B Patil
Plot No. 9, Rashtrasant Nagar, Godhani Road, Zingabai Takli, Nagpur - 440 030, Maharashtra
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Patil TB. Snake bite envenomation: A neglected public health problem in India.Med J DY Patil Univ 2013;6:123-125
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Patil TB. Snake bite envenomation: A neglected public health problem in India. Med J DY Patil Univ [serial online] 2013 [cited 2021 Dec 3 ];6:123-125
Available from: https://www.mjdrdypu.org/text.asp?2013/6/2/123/110286
Poisonous snake bites result in vast amount of suffering in a developing country like India. Highest morbidity and mortality occurs in rural and tribal people, who do not have an easy and early access to health services. We lose an important portion of our economically productive population, especially farmers due to snake bite. The problem is complicated by delay in seeking medical help or not seeking medical help due to belief in traditional healers. Furthermore, delay in transportation from remote places, lack of life supporting facilities and limited availability of anti-snake venom (ASV) in primary health centers take a heavy toll on human life. Unfortunately, the management of snake bite victims does not find an important place in our national health policy. This is reflected in lack of a systematic protocol and response system for treatment of snake bite envenomation. Important controversies in the management of snake bite include primary treatment of snake bite and dose of ASV.
India has over 250 species and subspecies of snakes, out of which 50 are venomous.  The "big four" venomous land snakes posing public health problem in India include Elapidae, which include cobra (Naja naja) and Krait (Bungarus caeruleus) and Viperidae, which include Russell's viper (Daboia russelii) and Saw-scaled viper (Echis carinatus). Elapidae are neurotoxic, whereas Viperidae are hemotoxic. Other poisonous snake species in India include central Asian cobra (Naja oxiana), monocellate cobra (N. kaouthia), greater black krait (Bungarus niger), Wall's and Sind kraits ( Bungarus walli and Bungarus sindanus) and west and hump-nosed pit-viper (Hypnale hypnale). 
Regarding number of snake bites and the related mortality in India, World Health Organization WHO (2010) guidelines state that estimates as low as 61,507 bites and 1124 deaths in 2006 and 76,948 bites and 1359 deaths in 2007 and as high as 50,000 deaths each year have been published.  In hospital-based studies, mortality rates ranged from 3% in northern India  to 20% in Nepal.  In Maharashtra, a state in India, an estimated 10,000 annual venomous snake bites account for 2000 deaths.  Maharashtra is one of the states of India with the highest incidence of snake bite. Gaitonde et al.  reported 70 bites per 100,000 population and mortality of 2.4 per 100,000 per year. Other states with a large number of snakebite cases include West Bengal, Tamil Nadu, Uttar Pradesh, and Kerala.  Based upon an epidemiological survey of 26 villages with a total population of nearly 19,000 individuals in Burdwan district of West Bengal state in India, Hati et al.  worked out an annual incidence of snake bite of 0.16% and mortality rate of 0.016% per year.
However, this all data may be a gross underestimation of the problem as a large number of snake bite victims do not reach health-care facilities and there is an underreporting of cases presenting to health-care facilities.
Pitfalls in Management of Snake Bite
The problems in management start with the bite itself. There are many superstitions and beliefs related to snake bite in our country. A person with snake bite is groped with fear, apprehension and terror despite of the fact that many snake bites are non-poisonous. Further, after snake bite important time is wasted attending traditional local healers. Many studies have shown that early administration of ASV results in better outcome and fewer complications in snake bite victims. Furthermore, ASV can neutralize only circulating snake venom and as the time elapses, more and more venom is bound to the target tissues, becoming less amenable to neutralization by ASV. So, it is important to make people aware of the fact that a time dependant treatment of snake bite is available and seeking early medical help is of immense important. Furthermore, medical practitioners should also be sensitized about early administration of ASV. So, the term "bite to needle time" in snake bite should assume more and more importance in medical literature just as the terms "door to needle time" or "door to balloon time" in management of acute myocardial infarction. ASV is a costly drug with limited availability at peripheral hospitals. So, in order to improve the outcome, it is important to ensure availability of ASV at even remote hospitals, so that the bite to needle time can be reduced.
The first aid measures after snake bite have been a matter of debate for long. It should be emphasized that applying a tight tourniquet to the affected limb is not recommended as it may lead to limb ischemia. In neurotoxic elapid snake bites, pressure immobilization with a light crepe bandage or long strip of any material is recommended. If a victim with a bandage comes to hospital, then it should not be removed until ASV treatment is started. Pressure immobilization should not be used in viper bites as this will increase local concentration of toxin with increase tissue necrosis. 
A distressing fact that is observed in many hospitals is overuse of ASV. It is used in doses as high as 100 ml three or four times a day for even 10-14 days so that the total dose for an individual goes into liters. ASV is administered in neuroparalytic snake bites even when the patient is on ventilator support. Further, ASV is indiscriminately administered even to patients not showing features of envenomation. This is an observation in government hospitals, even tertiary care hospitals where a more rational and evidence based approach is expected. Firstly, a single 10 ml vial of ASV costs INR 500. So, if a patient is administered such high-doses, the cost of ASV per patient is INR 100,000-150,000. This is a huge wastage of public money and resources. Further, it exposes the patient to the toxicity and side effects of such high-doses. It has been repeatedly been proven that low-dose ASV is as effective as high-dose ASV. This is not only cost effective but also safer approach. Indian National Snakebite Protocols 2007 recommends that an initial dose of 10 vials of ASV should be administered. After every 6 h, a clotting test such as 20 min whole blood clotting test (20 WBCT) should be repeated, and a repeat dose of ASV should be administered until the coagulopathy is restored. It also recommends that once the patient has received 20 vials of ASV or is in respiratory failure, further doses of ASV are not required.  This approach should be preferred over the arbitrary dosing system. WHO (2010) guidelines have recommended a further conservative dosing schedule.  To address this issue, we need further randomized controlled trials of ASV doses in various snake bite case, which will frame future guidelines. Furthermore, we need to train healthcare workers to follow the existent and future guidelines, which need a continuous medical education system.
Respiratory failure is an important cause of mortality in snake bite victims. Respiratory failure occurs in neuroparalytic snake bites due to paralysis of respiratory muscle paralysis. Such patients can be salvaged if they receive intubation and ventilatory support at the earliest. However, ventilators are not available at peripheral hospitals and even district hospitals. More importantly, doctors at peripheral hospitals are not skilled in endotracheal intubation. A potential solution is intubation at peripheral hospitals and Ambu bag ventilation until they can be transported to a hospital where facilities for mechanical ventilation are available. This needs training of doctors working in peripheral hospitals in endotacheal intubation with hands-on experience. Furthermore, "snake-bite units" should be established in district hospitals with facilities for mechanical ventilation, dialysis and medical staff with basic training in critical care medicine.
Acute renal failure occurs in about 20% snake bite patients.  Many patients need dialysis for management of acute renal failure. It has been shown that hemodialysis is a better modality for dialysis compared to peritoneal dialysis.  However, in a country like India, hemodialysis facilities are available only at tertiary care centers. Hemodialysis needs costly machines, dialysis membranes, central venous lines, expertise for central venous access, and technicians to operate hemodialysis machines. So, establishing such facilities even at district hospitals seems to be unlikely in the near future. In meanwhile, peritoneal dialysis appears to be a reasonable alternative. Peritoneal dialysis is less costly, as it only needs dialysis solution, catheters and lines. Doctors and nurses at community and district hospitals can be trained in peritoneal dialysis as it requires lesser skills compared to hemodialysis. Consequently, such dialysis facilities can be made available at community and district hospitals, reducing the burden on tertiary care hospitals.
Thus, a "chain of survival" in snake bite prevention and management would consist of following measures:
Creating awareness in rural and tribal people about measures for prevention of snake bites like avoiding sleeping on ground and use of protective footwear while working in fields. This may also need financial assistance to poor people.Public education for pressure immobilization technique of the affected limb as per WHO guidelines.Availability of ASV at primary, community and district health centers.Risk stratification of patients at Primary Health Centers and identification of at risk patients for transfer to higher center.Training of doctors at PHCs in quick respiratory assessment, endotracheal intubation and Ambu ventilation before transfer to higher center.Availability of basic investigations like hemogram, blood urea, serum creatinine, serum electrolytes, coagulation profile at community hospitals.Training of doctors and nursing staff at community and district hospital in peritoneal dialysis and to identify patients who may need dialysis.Establishing "snake bite units" in district hospitals.Continuous research and protocol development for better management of snake bite victims in tertiary care hospitals and medical colleges.
Most importantly, prevention, public education and management of snake bite envenomation must find a place in our national health policy to prevent loss of our economically productive population.
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