A retrospective study of the epidemiological and clinical profile of snakebites in an aspirational district of Karnataka

Abstract

Background:

Snakebite envenoming is a critical public health issue, recognized as the second-deadliest neglected tropical disease by the World Health Organization. In India, it accounts for an estimated 35,000 to 50,000 deaths annually, exacerbated by reliance on traditional remedies and underreporting of fatalities. This retrospective study analyzes the epidemiological and clinical profiles of snakebite cases at a secondary care hospital in Karnataka.

Methods:

Snakebite cases reported from January 2020 to April 2023 were analyzed. Data on demographics, clinical manifestations, treatments, complications, and outcomes were collected using case record forms. Descriptive statistics were applied using IBM SPSS Statistics version 25.0.

Results:

A total of 366 snakebite cases were reported, of which 121 (33.1%) were classified as venomous bites. The common krait (Bungarus caeruleus) was the most frequently identified species. The mean age of victims was 29.50 ± 14.62 years, and men (58.2%) were more frequently affected. Most bites occurred in the morning (51.9%), and 33.3% of victims sought traditional treatment before arriving at the hospital. Among all cases, 78.4% showed improvement, 16.7% were referred to higher centers, 3.3% left against medical advice, and 1.6% succumbed to complications.

Conclusions:

Snakebite remains a major public health concern in India, particularly among young males. Neurotoxic envenoming, predominantly due to the common krait, was most common in this study area. The frequent use of traditional medicine before seeking medical care underscores the need for community education and early referral to health care facilities. Strengthening awareness, timely administration of antisnake venom, and improved documentation are essential to reduce morbidity and mortality from snakebites.

Introduction

Snakebite envenoming (SBE) is a critical public health concern and is recognized as the second deadliest among neglected tropical diseases (NTDs).¹ In 2017, the World Health Organization (WHO) redesignated snakebite as an NTD, reversing its removal in 2013. This decision was influenced by the overwhelming burden of snakebites in tropical and subtropical regions, which account for 95% of the global caseload.² WHO's strategy emphasizes community engagement to prevent snakebites and improved training for health care workers to ensure prompt and effective treatment.³ Despite these global measures, SBE remains an overlooked issue in public health systems, particularly in rural and underserved regions.

The statistics surrounding SBE illustrate its devastating impact. Globally, snakebites affect approximately 4.5–5.4 million people annually, with 1.8–2.7 million experiencing envenomation. This results in an estimated 81,000 to 138,000 deaths and leaves approximately 400,000 survivors with lifelong disabilities, including amputations, disfigurements, and psychological trauma such as post-traumatic stress disorder.^4,5 These numbers reveal the immense strain SBE places on health care systems and the urgent need for scalable prevention and treatment strategies.

India bears the largest burden of SBE globally, with an estimated 35,000 to 50,000 deaths annually due to snakebites. However, underreporting remains a significant challenge. For instance, in 2007, official reports recorded only 1,331 snakebite deaths a gross underrepresentation likely caused by inadequate data collection systems.⁶ This discrepancy highlights the need for improved documentation and reporting mechanisms to understand the true magnitude of the problem. Moreover, reliance on traditional remedies in rural areas further complicates the management of snakebites, delaying access to lifesaving medical care.^7-9

The lack of reliable data hinders public health professionals from designing effective interventions for snakebite prevention and treatment.¹⁰ Epidemiological studies on SBE in India are typically conducted in tertiary care settings, leaving critical gaps in understanding the burden at secondary and primary healthcare levels.¹¹ Karnataka is one of India's states with a significant rural population, there is a lack of data on snakebite incidents. This gap is particularly concerning given the state's diverse topography, which includes areas with a high prevalence of venomous snake species. A retrospective data analysis is useful for assessing the burden and trends of diseases when there is a lack of robust data. Moreover, it can also provide insight into gaps in health care which helps in improving health care practices. A retrospective record-based study was planned to analyze the epidemiological and clinical profiles of suspected snakebite cases and to assess treatment outcomes at a secondary care facility in Karnataka, where the majority of snakebite cases in the region are being treated.

Materials and methods

Study design and setting

This record-based, retrospective, descriptive study was conducted at the Hutti Gold Mines Hospital, affiliated with the Hutti Gold Mines Company Limited, located in Lingasugur Taluk of Raichur District, Karnataka, India. Raichur is one of the aspirational districts identified under the Government of India's Aspirational Districts Programme, aimed at improving key indicators in health, education, agriculture, and infrastructure.

The Hutti Gold Mines Hospital is a secondary care facility with 120 beds, providing health care services to employees of the company and nearby rural populations at nominal cost. The hospital is staffed by 12 doctors, including specialists, and supported by 125 health care personnel. It serves as a referral centre for snakebite cases from surrounding villages.

Data source

Data on snakebite cases treated between January 2020 and April 2023 were obtained from the hospital's Medical Records Department.

Data collection procedure

Data were collected using a predesigned case record form by trained data collectors. Medical case sheets were reviewed to obtain relevant details. Any discrepancies were resolved through discussion with the investigators, and further clarification was sought from treating physicians when necessary.

Information extracted included demographic details (age, gender, and location of the incident), species of snake (when identified), time interval between bite and hospital arrival, bite site and timing, prior use of traditional medicine, and clinical manifestations (local, neurotoxic, or hemotoxic). Snake identification was based on either the dead snake brought to the hospital or photographs shown to the treating physician.

Laboratory findings, including 20-minute Whole Blood Clotting Test (WBCT), serum creatinine, clotting time, and urea levels, were recorded. Treatments such as anti-snake venom (ASV), atropine, neostigmine, intravenous fluids, and antibiotics were documented. Patient outcomes were noted as per the medical records, acknowledging that some variables had missing data.

Ethical considerations

No identifiable patient information was collected. The study protocol was approved by the Institutional Human Ethics Committee of MRHRU, Sirwar, and ICMR-NITM (ICMR-NITM/IHEC/2023-MAR/019), Belagavi, along with a consent waiver. The research adhered to the National Ethical Guidelines for Biomedical and Health Research Involving Human Participants as outlined by the ICMR in 2017.

Data analysis

The collected data were entered into a spreadsheet and analyzed using IBM SPSS v25.0. Descriptive statistics such as frequency, percentage, mean, and standard deviation were applied to summarize the data. The results were presented in tables and graphs for effective communication of findings. Treatment complications and outcomes were classified into categories: neurotoxic, hemotoxic, nonvenomous, and unclassified snakebite cases.

Results

This study included a total of 366 snakebite cases reported between January 2020 and April 2023. The snake species was identified in 130 cases (35.5%), while in 236 cases (64.5%), the species could not be determined. Based on clinical signs and symptoms of envenomation, 121 of the identified cases were caused by venomous snakes, and 9 cases were caused by nonvenomous snakes (Table 1).

Table 1.

Basic demographic details of snakebite victims^*

Basic demographic details
Variable	Mean (SD)
Age in years (n = 366)	29.50 (14.62)

Variables	Frequency (%)
Age categories (years)
Younger than 18	90 (24.6)
18–49	237 (64.8)
Older than 50	39 (10.7)
Duration of hospital stay in days (n = 360)	2.72 (3.6)
Gender (n = 366)
Male	213 (58.2)
Female	153 (41.8)
Place of snakebite (n = 26)
Field	16 (4.5)
Home	10 (2.7)
The type of snake identified (n = 130)
Neurotoxic
Cobra	21 (5.7)
Krait	73 (19.9)
Hemotoxic
Russell's viper	9 (2.5)
Saw scaled viper	18 (4.9)
Nonvenomous
Rat snake	09 (2.4)
Site of bite (n = 194)
Hand	35 (9.5)
Foot and Leg	156 (42.6)
Any other
Left Chest	1 (0.3)
Lip	1 (0.3)
Nose	1 (0.3)
Time of bite (n = 364)
Morning	190 (51.9)
Afternoon	96 (26.2)
Evening	69 (18.9)
Night	9 (2.5)
Traditional medicine used (n = 122)	122 (33.3)
Traditional medicine details (n = 122)
Ayurvedic treatment	3 (0.8)
Herbal medicine	113 (30.8)
Holy water	6 (1.6)
Time interval in hours between the snake bite and visiting the hospital
Min: 1, Max: 360	Median (Q1, Q3): 4 (2, 9)
Duration of hospital stay (n = 360) (d)
Min: 1, Max: 42	Median (Q1, Q3): 2 (1, 3)

^*Some data were not mentioned for all cases in the case record

The mean age of victims was 29.5 ± 14.6 years, with most (64.8%) aged between 18–49 years. Males constituted 58.2% of cases. Most snakebites occurred in the morning (51.9%). The lower extremities were the most common bite sites (42.6%).

Species identification revealed that the common krait (Bungarus caeruleus) was the predominant species (19.9%), followed by the Indian cobra (Naja naja) (5.7%), saw-scaled viper (Echis carinatus) (4.9%), and Russell's viper (Daboia russelii) (2.5%). Traditional medicine use was noted in 33.3% of cases, predominantly herbal preparations (30.8%), before arrival at the hospital. The median time from bite to hospital admission was 4 hours (inter quartile range: 2–9).

As shown in Table 2, the most frequent local manifestations were swelling (48.1%) and pain (42.9%). Ptosis (17.2%) was the most common neurotoxic symptom, followed by paralysis (11.5%), while ecchymosis (6.6%) was the most frequent hemotoxic symptom.

Table 2.

Distribution of symptoms of snakebite envenomation in the study

Variables (n = 366)	Frequency (%)
Local manifestations
Swelling at the Bite site	176 (48.1)
Pain at the Bite site	157 (42.9)
Blistering	11 (3.0)
Local necrosis	16 (4.4)
Neurotoxic Symptoms
Paralysis	42 (11.5)
Ptosis	63 (17.2)
Diplopia	02 (0.5)
Dysarthria	12 (3.3)
Dyspnoea	13 (3.6)
Dysphagia	05 (1.4)
Hemotoxic symptoms
Bleeding at the bite site	14 (3.8)
Ecchymosis	24 (6.6)
Systemic bleeding	04 (1.1)
Petechiae purpura	03 (0.8)

Among the tested cases, 21.6% had unclotted blood on 20-minute WBCT, 7.1% showed elevated serum creatinine (>1.3 mg/dL), and 22.1% had prolonged clotting time (>15 minutes). All snakebite cases had bleeding times within the normal range, and 4.6% of cases had urea levels exceeding 40 mg/dL (Table 3).

Table 3.

Laboratory findings among snakebite victims

Variables	Frequency (%)
20 minute WBCT (At the time of admission) (n = 282)
Clotted	203 (55.5)
Not clotted	79 (21.6)
Serum Creatinine (mg/dL) (n = 224)
Less than 1.3	198 (54.0)
More than 1.3	26 (7.1)
Clotting time (min) (n = 294)
Less than 15min	213 (58.1)
More than 15min	81 (22.13)
Blood urea (mg/dL) (n = 233)
More than 40	17 (4.6)

The highest number of snakebite cases occurred during the monsoon months, peaking in June (56 cases) and July (55 cases), while the lowest cases was reported in May (12 cases) (Fig. 1).

Figure 1.

Month-wise distribution of snakebite cases reported between January 2020 and April 2023.

Amongst 94 cases of neurotoxic snakebite, 95.7% received ASV, whereas in the remaining 4.25% cases ASV details were not available in the case sheets. Atropine was given in 48.94% and neostigmine in 46.81% cases. All cases received intravenous (IV) fluids, and 98.94% cases received IV antibiotics. Intubation was required in thirteen cases. Two cases each of compartment syndrome and gangrene, and three of coagulopathy were noted. Overall, 83% of neurotoxic cases improved, 6.4% were referred, and 2.1% died (Table 4).

Table 4.

Treatment, outcomes, and complications among snakebite victims

Variables	Neurotoxic (n = 94)*	Hemotoxic (n = 27)*	Non-venomous (n = 9)*	Unclassified snakebites (n = 236)*
Treatment given
ASV (n = 332)	90 (95.74)	26 (96.30)	6 (66.67)	210 (88.98)
Atropine (n = 69)	46 (48.94)	1 (3.70)	0 (0.00)	22 (9.32)
Neostigmine (n = 68)	44 (46.81)	0 (0.00)	0 (0.00)	24 (10.17)
IV Fluids (n = 362)	94 (100.00)	26 (96.30)	9 (100.00)	233 (98.73)
Antibiotic (n = 359)	93 (98.94)	27 (100.00)	8 (88.89)	231 (97.88)
Fasciotomy (n = 20)	0 (0.00)	20 (74.07)	0 (0.00)	0 (0.00)
Skin grafting (n = 2)	0 (0.00)	2 (7.41)	0 (0.00)	0 (0.00)
Intubation duration (h)
Up to 12 h (n = 9)	3 (3.19)	1 (3.70)	0 (0.00)	5 (2.12)
Up to 24 h (n = 12)	7 (7.45)	0 (0.00)	0 (0.00)	5 (2.12)
Up to 48 h (n = 3)	3 (3.19)	0 (0.00)	0 (0.00)	0 (0.00)
Complications
Systemic bleeding (n = 4)	0 (0.00)	4 (14.81)	0 (0.00)	0 (0.00)
Compartment syndrome (n = 19)	2 (2.13)	2 (7.41)	0 (0.00)	15 (6.36)
Gangrene (n = 8)	2 (2.13)	2 (7.41)	0 (0.00)	4 (1.69)
Coagulopathy (n = 79)	3 (3.19)	18 (66.67)	0 (0.00)	58 (24.58)
Serum creatinine >1.3mg/dl (n = 26)	0 (0.00)	26 (96.30)	0 (0.00)	0 (0.00)
Outcome
Improved (n = 287)	78 (83.02)	21 (77.78)	6 (66.67)	182 (77.12)
Referred (n = 26)	6 (6.38)	1 (3.70)	1 (11.11)	18 (7.63)
DAMA† (n = 2)	2 (2.13)	0 (0.00)	0 (0.00)	0 (0.00)
Dead (n = 2)	2 (2.13)	0 (0.00)	0 (0.00)	0 (0.00)

^*The values in the columns are frequency (column percentage).

^†Discharged against medical advice.

Among 27 hemotoxic snakebite cases, 26 (96.30%) cases received ASV. Fasciotomy was performed in 20 (74.07%) cases because of compartment syndrome. One patient required intubation for up to 12 hours. Hemotoxic snakebites were frequently linked to coagulopathy, affecting 18 (66.7%) cases, while other complications included gangrene and compartment syndrome in 2 (7.41%) cases each. Serum creatinine levels greater than 1.3 mg/dL were reported in 26 (96.30%) cases, and there was no documentation of haemodialysis requirements for patients with acute kidney injury in the case sheets. Improvement was noted in 21 (77.8%) cases. Among the nonvenomous snakebite cases (n = 9), all received supportive treatment, including IV fluids, and 8 (88.9%) received antibiotics. A total of 6 (66.7%) cases received ASV. These 6 cases were given ASV due to a misidentification of the snake before arriving at the hospital, which was later identified as a nonvenomous rat snake. In 236 unclassified snakebite cases, ASV was administered in 210 (88.98%) cases, and antibiotics were given to 231 (97.88%), although the specific species causing envenomation were not documented in the medical records. Five patients required intubation for durations of up to 12 and 24 hours, respectively. For complications like gangrene, documentation was lacking for the intervention performed, including the amputation. The 77.1% unclassified cases showed recovery (Table 4). The outcomes of the referred and discharge against medical advises cases were not recorded.

Overall, raised serum creatinine levels (>1.3 mg/dL) was the most common complication seen in 7.1% cases, primarily observed with hemotoxic snakebites. Coagulopathy was the most common complication in 21.6% cases. Compartment syndrome was documented in 5.2% cases, and fasciotomy was performed in 5.5% cases. Systemic bleeding occurred in 1.1% cases, while gangrene was observed in 2.2% cases.

Discussion

This retrospective analysis provides insights into the epidemiology, clinical presentation, and management gaps in snakebite cases. The mean age of victims (29.5 ± 14.6 years) aligns with previous studies, such as David et al (2012) (32 ± 15.9 years), Gajbhiye et al (2019) (33.2 ± 1.2 years), and Kalantri et al (2006) (33 ± 12 years). Male predominance (58.2%) was slightly lower compared with Kalantri et al (2006) (67.9%) and Chakraborty et al (2020) (74.4%), but similar to Patel et al (2021) (60.5%).^12–16

Geographical variations in snake species prevalence were evident, with Common kraits, (B. caeruleus) (19.9%) being the most frequently identified, compared with Chakraborty et al (2020), where Russell's vipers accounted for 58.04%. Most bites (42.6%) occurred on the lower extremities, comparable with studies done by Gajbhiye et al (2019) (63.5%) and David et al (2012) (71.7%). Variability in timing was observed, with 51.9% occurring in the morning, contrasting with Chakraborty et al (2020) (57.94% in the evening) and Mandal et al (2021) (71.96% at night), likely reflecting regional occupational patterns. Notably, 33.3% of victims sought traditional medicine before hospital care, in line with Alcoba et al (2020) (38%) but lower than Vongphoumy et al (2015) (100%) and Snow et al (1994) (78%), contributing to delayed ASV administration and poorer outcomes, reflecting the faith in traditional medicine and the availability of doctors and ASV.^{1,7,12,13,15,17–19}

Local manifestations included swelling (48.1%) and pain (42.9%), similar to Melit et al (2021) (91.6%) but higher than Bawaskar et al (2008) (21.9%) studies. Neurotoxic symptoms such as ptosis (17.2%) and paralysis (11.5%) were lower than Mandal et al (2021) (75.7% ptosis) and David et al (2012) (62.3% ptosis) studies. Compared with Ghosh et al (2018), where gangrene occurred in 14.8% and renal failure in 9%, our study showed a lower incidence. ASV was administered to 90.7% of patients, slightly higher than Karanth et al (2023) (84.6%), with no recorded adverse reactions.^{6,12,17,20–23}

Overall, 78.4% of patients improved, lower than Mandal et al (2021) (96.2%). Improvement rates were higher in neurotoxic (83.02%) and hemotoxic (77.8%) cases compared with nonvenomous and unclassified cases (67% and 77.1%, respectively). Referral was required in 7.1% of cases, and mortality was 0.5%, though causes of death were often undocumented. Late presentation and reliance on traditional medicine likely contributed to poorer prognoses. Strengthening early recognition, adherence to standardized ASV protocols, and improved record-keeping are essential for optimizing snakebite management outcomes.¹⁷

Limitations

As this study was conducted in a single hospital, the results may not be generalizable to other settings. Some of the information was incomplete, which made it difficult to analyze certain patterns fully and reduced the number of participants included in the analysis. Since the study relied on existing records, the accuracy of the findings depended on how well the data were originally collected and documented, and any errors or inconsistencies may have contributed to the gaps. The missing data may also have introduced bias if the cases excluded due to incomplete information were different from those included, potentially affecting how well the results apply to a broader population. As a single value of serum creatinine was available in case sheets it was insufficient to attribute it to SBE.

Recommendations

To improve clinical outcomes for snakebite patients, especially in rural facilities, healthcare professionals should receive regular training on standardized snakebite management protocols. Community awareness campaigns are essential to reduce dependence on traditional healers and promote timely hospital care. Enhancing knowledge of ASV availability and improving hospital data recording systems will support evidence-based decision-making and policy planning, ultimately strengthening the overall health care system's capacity to respond effectively to snakebite incidents.

Conclusion

Snakebite envenomation remains a major public health issue in this aspirational district of Karnataka, predominantly affecting young adults. Many victims initially seek traditional healers, delaying effective treatment. Most bites occur during the monsoon season, with the common krait as the most frequently involved species. Common symptoms included local swelling, pain, and ptosis. Strengthening early treatment access, awareness, and hospital documentation can substantially reduce morbidity and mortality.