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Snakebite: admissions at a tertiary health care centre in Maharashtra, India.

Snakes are found all over the world except in the Arctic, New Zealand and Ireland, and are more commonly distributed in temperate and tropical countries. (1) Snakes are most likely to bite human beings when they feel threatened, startled or provoked, and/or have no means of escape when cornered. Snakes are likely to approach residential areas when attracted by prey, such as mice and frogs. The Deccan plateau, with its agricultural land and hot, dry climate, provides an ideal environment for cobras, kraits and vipers. (2) Snakebite is generally considered to be a rural problem and has been linked with environmental and occupational conditions. (3) Most houses in the rural areas of India are made of mud and have many crevices where rodents flourish. Snakes have easy ingress to such houses and often enter them in search of food. Firewood and dried cow dung, stored in or near the house, provide ready shelter for snakes and rodents. (4)

Morbidity and mortality from snakebite envenomation depends on the species of snake, since the estimated fatal dose of venom varies among species. In India, almost two-thirds of the bites are attributed to the saw-scaled viper (as high as 95% in some areas such as Jammu (5)), about a quarter to Russell's viper, and smaller proportions to cobras and kraits. (6)

Snakebite is an important and serious medical problem in many parts of India. However, reliable data for morbidity and mortality are not available since there is no proper reporting system. Moreover, many cases are not recorded in official statistics, as people seek traditional treatment methods. Most snakebite studies in India deal with clinical and management aspects, and there are few epidemiological studies. (7) We studied the epidemiology of snakebite cases over a period of 10 years.

Aim and objectives

We aimed to study the epidemiology of snakebite cases admitted to hospital; trends of snakebite and death from snakebite; seasonal variations; and the outcomes of snakebite cases.


In a record-based retrospective descriptive study, we evaluated snakebite cases admitted to the hospital from 1999 to 2008. Data were collected from the Medical Records Department of the Dr Shankarrao Chavan Government Medical College. Recorded information was entered in a pre-coded pro forma and included age, sex, residence, site of bite, type of snake poison, whether cases had been directly admitted to this hospital or referred from other health centres, time interval between snakebite and initiation of treatment, and the outcomes of snakebite cases. The total number of hospital admissions for different illnesses during 1999-2008 was 488 344. As required by the government of Maharashtra, all snakebites are classified as medico-legal cases, whose records are kept separately in the medical records department. The total number of cases registered during the above period was 5 718. We evaluated only the records of snakebite cases where outcomes were recorded as recovered and discharged from hospital, or died while in hospital. Excluded were snakebite patients who absconded or were discharged against medical advice, and where records were incomplete. Of the total of 5 718 snakebite cases, 179 records were not evaluated owing to incomplete diagnosis, and patients absconded or discharged against medical advice. Hence, 5 639 records of snakebite cases were evaluated. The statistical tests applied were percentage and chi-square test, wherever applicable.


The age and sex distribution of the 5 639 cases studied is shown in Table I. Snakebite was most common (57.7%) in the age group 31-45 years, followed by the 16-30-year age group (27%), constituting a total of 84.7%. Males were more prevalent than females, the ratio being 2:1. Most snake bites (3 115-55.2%) were seen during July-September, which coincides with the rainy season in this region, followed by 1 210 (21.5%) cases during October-December. Fewer cases were seen in the first and second quarters of the year--442 (7.8%) and 872 (15.5%), respectively (Table II).

Bites occurred on a lower limb in 4 642 (82.3%) cases, and an upper limb in 747 (13.3%) cases. Less common sites were the trunk in 107 (1.9%), face 113 (2%), and other parts of the body such as the neck or buttock in 30 (0.5%) cases.

Of the 5 639 cases, 2 596 (46%) were referred from other health care centres (mostly rural), while 3 043 (54%) were admitted directly to our hospital. All the referred cases received tetanus toxoid before admission to this hospital. Some cases also received antibiotic treatment and antivenoms (AVs). The total numbers of snakebite cases per year and snakebite mortality from 1999 to 2008 are shown in Table III. The number of snakebite cases per 1 000 admissions per year remained between 8.45 and 13.31 during 1999-2008, and the proportional mortality rate due to snake bite remained between 1.25 and 2.86.

Table IV shows case fatality rates from snakebite by age and sex. Fatality rates were higher in subjects <15 years old (11.9%) and in the 46-60-year-old age group (11.8%). The fatality rate was much higher (8.8%) in females than males (3.7%).

In this study, 70.5% of cases were from rural areas and 29.5% from urban areas. Snakebite mortality was higher in cases from rural areas (6.3%) than urban areas (3.4%) (Table V).

The prognosis for snakebite cases depends on various factors in addition to their treatment, including first aid immediately after the bite, early initiation of appropriate treatment, and the type of envenomation (Table VI). In this study, 3 446 snakebite cases received first aid in the form of a tourniquet or incision over the bite, or sucking on the bite. The mortality among those who received first aid before coming to the hospital was less (3.1%) than among those who did not receive first aid (9.2%.) This difference is statistically significant ([chi square]=95.36, df=1, p<0.01).

Mortality was higher (8.4%) where the time interval between the snakebite and initiation of treatment was >6 hours, while it was less (4.4%) where treatment occurred within 6 hours. These findings were statistically significant ([chi square]=29.11, df=1, p<0.01).

The type of venom could not be ascertained in 1 361 cases. Mortality from neurotoxic venom was 8.9%, and 4.2% from vasculotoxic. The difference in mortality from these venoms was statistically significant (%2=21.29, df=1, p<0.01)


In the present study, snakebite was most common (57.7%) in the 31-45-year age group, followed by the 16-30-year-old age group (27%), these groups constituting a total of 84.7% of the total. Bites were more frequent in males than females, the ratio being 2:1. Others have reported similar observations. (8-12)

The 16-45-year age group is most active in various outdoor occupations, involving males more than females. Hence males are most prone to snakebites, as seen in this study.

Most snakebite cases (3 115-55.2%) were seen in the months of July to September, which coincides with the rainy season in this region, followed by 1 210 (21.5%) cases during October to December. During the rainy season, rainwater floods their burrows and snakes then try to take shelter near human dwellings, which increases the chances of snakes feeling threatened or startled or provoked by human beings, and biting them in defence. The distribution of snakebite cases in different quarters of the year was uneven, and was statistically significant ([chi square] for goodness of fit=2960, df=3, p<0.001) and similar to other studies. (7,9,13,14)

In this study, most bites (4 642-82.3%) were on a lower limb, and on an upper limb in 747 (13.3%) cases. When farm workers are in the fields, cutting grass, etc., their lower limbs, hands and fingers are closest to ground level. Consequently, snake bites are more common on the lower and upper extremities. (8) External factors that are not in control of the hospitals, which increase the chances of mortality in admitted cases, include not receiving first aid, unavailability of AV at health centres in rural areas, no transport facilities, and lack of public awareness about the urgency of treatment. Hence, during the study period, snakebite cases per 1 000 admissions per year and proportional mortality rate remained somewhat similar. Children, older people and females are more prone to die from snakebites. In our study, the case fatality rates were greater in subjects <15 years old (11.9%) and in the 46-60 years age group (11.8%). The case fatality rate was much higher (8.8%) in females than in males (3.7%), which is similar to another report. (8) In India, owing to cultural attitudes, male health care is often considered more important than that for females. Probably this factor resulted in immediate treatment-seeking behaviour for males and less importance being accorded to females.

Mortality from snakebite was higher in cases from rural areas (6.3%) than in those from urban areas (3.4%). Dwelling conditions in rural areas of India are more favourable for the habitation of snakes, and most rural people are engaged in agricultural work, which leads to more snakebites and consequent mortality.

The prognosis for snakebites depends on factors besides hospital treatment: whether first aid is given immediately after the bite, early initiation of appropriate treatment, and the type of venom. In this study, mortality among those who received first aid before coming to the hospital was lower (3.1%) than among those who did not receive first aid (9.2%). First aid in the form of a firm bandage, immobilising the bitten area, and incising to draw blood was applied by many patients. Mortality was higher (8.4 %) in cases where the time interval between the bite and initiation of treatment was more than 6 hours, and lower (4.4%) among those who received treatment within 6 hours. Mortality from neurotoxic snakebite was higher (8.9%) than that from vasculotoxic snakebite (4.2%).

As a tertiary health care teaching hospital, our hospital has facilities for managing snakebite cases. Our apparently high mortality rate may be due to the delay in arriving at the hospital after the snakebite, since most patients came from 80 to 100 km away, and perhaps due to patients initially seeking treatment from traditional healers and local practitioners.


(1.) Mulay DV, Kulkarni VA, Kulkarni SG, Kulkarni ND, Jaju RB. Clinical profile of snakebites at SRTR Medical College Hospital, Ambajogai (Maharashtra). Indian Medical Gazette 1986; 131: 363-366.

(2.) Banerjee RN. Poisonous snakes of India, their venoms, symptomatology and treatment of envenomation. In: Ahuja MMS, ed. Progress in Clinical Medicine in India. Vol 2. New Delhi: Arnold-Heinemann Publishers (India), 1978: 136-179.

(3.) Hati AK, Mandal M, Mukerjee H. Epidemiology of snakebite in the district of Burdwan. Jof Indian Med Assoc 1992; 90: 145-147.

(4.) Bawaskar H S, Bawaskar P H. Profile of snakebite envenoming in western Maharashtra, India. Trans R Soc Trop Med Hyg 2002; 96: 79-84.

(5.) Bhat RN. Viperine snake bite poisoning in Jammu. J Ind Med Assoc 1974; 63: 383-392.

(6.) Saini RK, Sharma S, Singh S, Pathania NS. Snake bite poisoning: A preliminary report. J Assoc Phys India 1984; 32(2): 195-197.

(7.) Lal P, Dutta S, Rotti SB, Danabalan M, Kumar A. Epidemiological profile of snakebite cases admitted in JIPMER Hospital. Indian Journal of Community Medicine 2001; 26(1): 36-38.

(8.) Punde DP. Management of snake-bite in rural Maharashtra: A 10-year experience. Nat Med J India 2005; 18: 71-75.

(9.) Brunda G, Sashidhar RB. Epidemiological profile of snake-bite cases from Andhra Pradesh using immunoanalytical approach. Indian J Med Res 2007; 125: 661-668.

(10.) Kulakarni ML, Anees S. Snake venom poisoning: experience with 633 cases. Indian Pediatr 1994; 31: 1239-1243.

(11.) Buranasin P. Snake bites at Maharat Nakhon Ratchasima Regional Hospital. Southeast Asian J Trop Med Public Health 1993; 24: 18^192.

(12.) Rano M. A study of snake bite cases. J Pak Med Assoc 1994; 44: 289.

(13.) Nhachi CF, Kasilo OM. Snake poisoning in rural Zimbawe: A prospective study. J Appl Toxicol 1994; 14: 192-193.

(14.) Ribeiro LA, Jorge MT, Iversson LB. Epidemiology of accidents due to bites of poisonous snakes: a study of cases attended in 1988. Revista de Saude Publica 1995; 29: 380-388.

Accepted 2 March 2010.

Department of Community Medicine, Dr Shankarrao Chavan Government Medical College and Hospital, Vazirabad, Nanded District, Maharashtra State, India

I F Inamdar, MD

N R Aswar, MD

S D Dalvi, MD

Department of Medicine, Dr Shankarrao Chavan Government Medical College and Hospital

M Ubaidulla, MD

Corresponding author: I Inamdar (
Table I. Age and sex distribution

Age (yrs) Male (%) Female (%) Total (%)

<15 245 (6.7) 168 (8.6) 413 (7.3)
16 - 30 980 (26.6) 542 (27.6) 1 522 (27.0)
31 - 45 2 142 (58.2) 1 110 (56.6) 3 252 (57.7)
46 - 60 172 (4.7) 82 (4.2) 254 (4.5)
>60 140 (3.8) 58 (3.0) 198 (3.5)
Total 3 679 (100) 1 960 (100) 5 639 (100)
 (65.2) (34.8) (100)

Table II. Quarterly snakebite incidence

Months Total cases Percentage

January - March 442 7.8
April - June 872 15.5
July - September 3 115 55.2
October - December 1 210 21.5
Total 5 639 100

[chi square]2 for goodness of fit=2 960, df=3, p<0.001.

Table III. Snakebites per year and mortality from snakebite 1999--2008

 No. of Deaths from
Year admissions No. of deaths Snakebite cases snakebite (%)

1999 44 904 1 703 598 38 (6.35)
2000 45 261 1 547 458 31 (6.77)
2001 44 365 1 256 588 36 (6.12)
2002 43 169 1 125 526 31 (5.89)
2003 49 742 1 447 515 26 (5.05)
2004 51 210 1 428 668 38 (5.69)
2005 50 943 1 280 588 28 (4.76)
2006 53 618 1 568 655 36 (5.50)
2007 54 056 1 398 611 28 (4.58)
2008 51 076 1 196 432 15 (3.47)
Total 488 344 13 948 5 639 307 (5.44)

 Snakebite cases per Proportional mortality
Year 1 000 admissions rate from snakebite

1999 13.31 2.23
2000 10.11 2.00
2001 13.25 2.86
2002 12.18 2.75
2003 10.35 1.79
2004 13.04 2.66
2005 11.54 2.18
2006 12.21 2.29
2007 11.30 2.00
2008 8.45 1.25
Total 11.54 2.20

Table IV. Fatality rates by age and sex

 Male Female

 No. of Case fatality No. of Case fatality
Age (years) deaths rate deaths rate

<15 15 6.12 34 20.24
16-30 37 3.78 46 2.95
31-45 59 2.76 67 6.04
46-60 17 9.88 13 15.85
>60 7 5.00 12 20.69
Total 135 3.67 172 8.78


 No. of Case fatality
Age (years) deaths rate

<15 49 11.86
16-30 83 5.45
31-45 126 3.87
46-60 30 11.81
>60 19 9.60
Total 307 5.44

[chi square] =63.77, df=1, p<0.01.

Table V. Rural and urban snakebite prevalence

Location No. of cases (%) Deaths Mortality (%)

Rural 3 974 (70.47) 251 6.32
Urban 1 665 (29.53) 56 3.36
Total 5 639 (100.00) 307 5.44

[chi square] =19.9, df=1, p<0.05.

Table VI. Prognostic factors other than treatment and mortality

 Deaths from
Factors Total cases snakebite (%) p-value

First aid
 Received 3 446 106 (3.07)
 Not received 2 193 201 (9.16) p< 0.01
Interval before
 <6 hours 4 162 183 (4.39)
 >6 hours 1 477 124 (8.39) p<0.01
Type of
 Neurotoxic 1 133 101 (8.91%)
 Vasculotoxic 1 244 52 (4.18%) *p<0.01
 Unknown 1 361 154 (11.32%)

* Neurotoxic v. vasculotoxic.
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Article Details
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Title Annotation:Original Articles
Author:Inamdar, I.F.; Aswar, N.R.; Ubaidulla, M.; Dalvi, S.D.
Publication:South African Medical Journal
Article Type:Report
Geographic Code:9INDI
Date:Jul 1, 2010
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