Clinical profile, species-specific severity grading, and outcome determinants of snake envenomation: An Indian tertiary care hospital-based prospective study

Snakebite-Associated Infections: A Systematic Review and Meta-Analysis

Snakebites still constitute a significant public health problem in developing countries and are considered a neglected tropical condition by the WHO. Snake accidents are associated with substantial morbidity and mortality and may produce secondary complications, such as severe infections. The objective of this systematic review was to determine the prevalence of snakebite infections and characterize the bacteria isolated from these infections. A systematic literature review in five databases was carried out to assess the prevalence of snakebite infection. A meta-analysis was performed using a random-effects model to calculate the pooled prevalence and 95% CIs. Cochran's Q test and the I2 statistic were used to assess between-study heterogeneity. The pooled prevalence of infection due to snakebite was 27.0% (95% CI: 22.0-32.0%), with high heterogeneity among studies (I2 = 99.7%). The prevalence was higher in Asia (32%) than in the Americas (21%). Snakebite infections required surgical interventions in 68% (95% CI: 37.0-98.0%). The leading group of pathogens identified corresponded to Gram-negative bacteria (63%), particularly Morganella morganii (32%), but also, Gram-positive cocci (40%), especially Enterococcus spp. (23%) and Staphylococcus aureus (15%). However, multiple other pathogens, including anaerobes, were found. A high prevalence of snakebite-associated infection has been described, primarily due to M. morganii, with the corresponding implications for empirical therapy. Rational use of antimicrobials is recommended, and this should guide initial empirical treatment. Moreover, isolation and identification of the possible bacteria present in snakebite wounds is recommended in all cases to confirm or rule out associated infection.

Use of Antibiotics following Snakebite in the Era of Antimicrobial Stewardship

Even though there are guidelines for the management of snakebite envenoming (SBE), the use of antibiotics in this pathology remains controversial. The aim of this study is to provide a narrative review of the literature and recommendations based on the best available evidence regarding antibiotic use in SBE. We performed a narrative review of relevant literature regarding SBE and antibiotic use as prophylaxis or treatment. A total of 26 articles were included. There is wide use of antibiotics in SBE; nevertheless, infection was not necessarily documented. The antibiotics used varied according to the study, from beta lactams to lincosamide and nitroimidazoles, and from monotherapy to combined antimicrobials. The most common recommendations were to manage skin and soft tissue infections and avoid infectious complications, but these suggestions are not necessarily based on bacteriological findings. Prophylactic use of antibiotics in SBE is discouraged in most studies. Antibiotic prescription in SBE should be based on the susceptibility of microorganisms isolated from the affected tissue or identified in snakes' oral cavities. Antibiotics should be reserved only for patients with a demonstrated infection, or those at a high risk of developing an infection, i.e., presenting severe local envenoming, local signs of infection, or those with incorrect manipulation of wounds. Prospective studies are needed to correlate microbiological findings at the wound site and the response to antibiotic use.

Evaluation of Neutralization Potential of Naja naja and Daboiarusselii Snake Venom by Root Extract of Cyanthillium cinereum

Aim

One of the main reasons for the death due to snake bites is the non-availability of antivenoms in the regions where they are needed. The use of medicinal plants and plant-based natural products as an alternative to antivenom will become a milestone in snake bite envenomation. The present study investigates the in vitro antivenom properties of Cyanthillium cinereum root extracts.

Materials and methods

The C. cinereum root's aqueous extract was prepared by the Soxhlet extraction method, and phytochemical screening was performed to detect the presence of various bioactive compounds. Thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS) analysis were performed for the detection and identification of phytochemical constituents. In this study, an in vitro model is used to assess the antivenom capability of aqueous extract. Venom toxicity and neutralization assays were as follows: An in vitro pharmacological evaluation was performed by direct hemolysis assay, indirect hemolytic assay, proteolytic activity, neutralization of procoagulant activity, and gelatin liquefaction method.

Results

Qualitative analysis of phytochemicals by the standard method showed the presence of various phytochemical constituents. Also, GC-MS analysis showed the presence of three major compounds that possess antivenom activity from the obtained 60 bioactive compounds, and their chemical structures were also determined. Venom protein profiling was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The plant extract was able to neutralize the Naja naja (N. naja) and Daboia russelii (D. russelii) venom induced hemolysis and it was reduced below 50 and 40%, respectively and the extract was also able to reduce the hemolytic halo produced by venoms. Procoagulant activity and gelatin liquefaction assay showed that venom-induced clotting was neutralized by increasing the root extract concentration sufficiently.

Conclusion

The aqueous extract of the root of C. cinereum showed potent in vitro venom-neutralizing activity, and it can be used as a formidable therapeutic agent against N. naja and D. russelii envenomation.

How to cite this article

Suji S, Dinesh MD, Keerthi KU, Anagha KP, Arya J, Anju KV. Evaluation of Neutralization Potential of Naja naja and Daboia russelii Snake Venom by Root Extract of Cyanthillium cinereum. Indian J Crit Care Med 2023;27(11):821-829.

A retrospective analysis of epidemiology, clinical features of envenomation, and in-patient management of snakebites in a model secondary hospital of Assam, North-east India

Assam, a Northeastern State of India, is inhabited by several venomous snake species causing substantial morbidity and mortality. The data on the epidemiology of snakebites and their management is underreported in this region. Hence, a secondary health-based retrospective study was carried out at Demow Model Hospital, Sivasagar, Assam, to evaluate the clinical and epidemiological profile of snakebite cases reported in this rural hospital and their management. Snakebites occurring between April 2018 to August 2022 were reviewed based on socio-demographic details of the patient, clinical symptoms, and treatment using a standard questionnaire. Out of the 1011 registered snakebite cases, 139 patients (13.7%) counted for venomous bites, among which 92 patients (66.19%) accounted for viper bites (green pit viper and Salazar's pit viper), and 30 patients (21.5%) were bitten by elapid snakes (Indian monocled Cobra, banded krait, and greater/lesser black krait). A maximum number of snakebite cases (80.5%) were reported from the interior rural villages and documented from July to September (51.3%). Elapid snake envenomed patients, except one, were successfully treated with commercial antivenom, neostigmine, and glycopyrrolate. Because commercial polyvalent antivenom against "Big Four" venomous snakes of India showed poor neutralization of pit-vipers envenomation; therefore, pit-viper bite patients were treated with repurposed drugs magnesium sulfate and glycerin compression dressing. Adverse serum reactions were reported only in 3 (11.1%) cases. The preventive measures and facilities adopted at the Demow Model Hospital significantly reduce snakebite death and morbidity; therefore, they can be s practised across various states in India as a prototype.

The concept of Big Four: Road map from snakebite epidemiology to antivenom efficacy

Snake envenomation is a life-threatening disease caused by the injection of venom toxins from the venomous snake bite. Snakebite is often defined as the occupational or domestic hazard mostly affecting the rural population. India experiences a high number of envenoming cases and fatality due to the nation's diversity in inhabiting venomous snakes. The Indian Big Four snakes namely Russell's viper (Daboia russelii), spectacled cobra (Naja naja), common krait (Bungarus caeruleus), and saw-scaled viper (Echis carinatus) are responsible for majority of the snake envenoming cases and death. The demographic characteristics including occupation, stringent snake habitat management, poor healthcare facilities and ignorance of the rural victims are the primary influencers of high mortality. Biogeographic venom variation greatly influences the clinical pathologies of snake envenomation. The current antivenoms against the Big Four snakes are found to be less immunogenic against the venom toxins emphasizing the necessity of alternative approaches for antivenom generation. This review summarizes the burden of snake envenomation in India by the Big Four snakes including the geographic distribution of snake species and biogeographic venom variation. We have provided comprehensive information on snake venom proteomics that has aided the better understanding of venom induced pathological features, summarized the impact of current polyvalent antivenom therapy highlighting the need for potential antivenom treatment for the effective management of snakebites.

Hypocholesterolaemia as a prognostic factor in venomous snakebite: a retrospective study from a single centre in Kerala, India

BACKGROUND

Studies have suggested a association between serum cholesterol values and severity of envenoming. The objective of the study was to correlate the serum cholesterol levels with severity of envenoming in victims of snakebite, across snake species in our patient population.

METHODS

Retrospective secondary data analysis of health records of a cohort of snakebite victims treated at Little Flower Hospital, Angamaly, Kerala during June 2006-January 2008 was performed. The cholesterol values were assessed in 205 consecutive patients admitted with snakebite envenoming, within 24 h of admission and 10 h of overnight fasting. Lipid fractions were estimated from fasting serum through the standard CHOD-PAP method on a Hitachi analyzer. The cholesterol level was compared between victims with mild and serious envenoming to assess the proportion among each category with a low cholesterol (defined as ≤150 mg/dl as per institutional criteria). In addition, low cholesterol as a marker of severity was compared with other laboratory parameters suggesting severe envenoming such as low fibrinogen, low platelet count, neutrophilia, elevated creatinine, d-dimer, hepatic transaminases and albuminuria.

RESULTS

Of the 146 victims with serious degree of snakebite envenoming 116 (79%) had low cholesterol values ≤150 mg%, while 30 (21%) had values >150 mg%. Of the patients with low cholesterol, 116 (78%) had serious envenoming, while 22% had mild envenoming. By contrast, 30 patients (21%) had values >150 mg%. The risk of moderate-severe envenoming with low cholesterol was 2.7 times (170%) that of victims with normal or high cholesterol on admission.

CONCLUSIONS

A low cholesterol on admission in victims of snake envenoming suggested a more severe degree of envenoming and likelihood of complications.

Bite-to-needle Time - An Extrapolative Indicator of Repercussion in Patients with Snakebite

Background

Snakebite is a significant occupational and environmental hazard in tropical countries. The treatment of snakebite includes care of the wound, supportive care, and administration of anti-snake venom (ASV). Time is crucial to reducing the morbidity and mortality of patients. This study aimed to assess the "bite-to-needle time" with morbidity and mortality of snakebites and correlate it.

Patients and methods

A total of 100 patients were included. Detailed history included the time since snakebite, bite site, species of snake, and symptoms at presentation, which included level of consciousness, cellulitis, ptosis, respiratory failure, oliguria, and bleeding manifestations. "Bite-to-needle time" was noted. Polyvalent ASV was administered in all patients. Duration of hospitalization and complications, including mortality were noted.

Results

The age-group of the study population was 20-60 years. About 68% were males. Krait was the commonest species (40%), and the lower limb was the commonest bite site. Within 6 hours, 36% of patients received ASV, and between 6 and 12 hours, 30%. Patients with a bite-to-needle time of under 6 hours spent less time in the hospital and experienced fewer complications. Patients with bite-to-needle times longer than 24 hours had more ASV vials, complications, hospital-stay length, and death.

Conclusion

An increase in bite-to-needle time increases the chances of systemic envenomation, hence, the severity of complications or morbidity and risk of mortality increases. The necessity of timing and the value of administering ASV on time must be emphasized to the patients.

How to cite this article

Jayaraman T, Dhanasinghu R, Kuppusamy S, Gaur A, Sakthivadivel V. Bite-to-needle Time - An Extrapolative Indicator of Repercussion in Patients with Snakebite. Indian J Crit Care Med 2022;26(11):1175-1178.

Snakebite profile from a tertiary care setup in a largely rural setting in the hills of North-West India

Background:

Snakebite, a medical emergency, faced by rural populations in tropical and subtropical countries assumes special significance in hilly terrains. Therefore, the hills provide a natural setting to study the challenges in the management of snakebite cases.

Methodology:

A hospital record-based retrospective descriptive study was conducted. Data were collected from the Medical Records Department of the 821-bedded, tertiary care hospital catering to the rural hilly population of the state of Himachal Pradesh, India. Information were recorded on details of demography, clinical profile treatment and outcome.

Results:

A total of 252 patients were analyzed. Maximum patients were in the age-group of 21–40 (43.7%) with mean and standard deviation of 30.52 ± 5.693 and 31.81 ± 7.117 for male and female, respectively. A small minority (17.06%) of patients reported to health facility within 4–6 h of the bite. Maximum bites were on lower limb (143;56.74). Overall mortality rate in our study was 2.38%.

Conclusion:

Large-scale studies on epidemiological determinants of snakebite coupled with research in venom biochemistry and bio-pharmacology of anti-snake venom (ASV) are needed. The study also provides insights into the role of primary care practitioners in creating an ecosystem favorable for snakebite management at local level.

Influential Factors of Local Tissue Necrosis after Taiwan Cobra Bites: A Secondary Analysis of the Clinical Significance of Venom Detection in Patients of Cobra Snakebites

Local tissue swelling, inflammation, and wound necrosis are observed in Taiwan cobra bites. Knowledge of the factors influencing local tissue necrosis after cobra bites might improve the cobra bite treatment strategy. Therefore, we aimed to explore the factors influencing local tissue necrosis after cobra bites. This was a retrospective observational cohort study. All patients clinical presentations including serum venom levels for determining the influential factors in this study were obtained from Hung et al.’s previous study. Clinical features, such as bite information, initial swelling, patient presentation time, serum venom levels, and antivenom, use were extracted. The measurement outcome was the development of wound necrosis. The factors influencing wound necrosis were investigated using univariate and logistic regression analyses. The influential factors of local tissue necrosis and their areas under the curve were: initial limb swelling, 0.88; presentation time × serum level, 0.80; initial necrosis, 0.75; patient presentation time, 0.70. Serum venom level alone cannot be used as a predictive factor. The development of tissue necrosis might be associated with the venom factor, time factor, and their interaction. These influential factors can be used in future studies to evaluate antivenom efficacy.

The study of clinical profile and outcome of patients with snakebite in a rural community

Context:

Snakebite remains an underrated cause of accidental death in modern India, primarily in rural India, where people fail to reach out to modern medicine and fall victim to the handful of quacks using traditional healing methods. If promptly diagnosed and treated based on various clinical determinants like mode of presentation, time of medical intervention, recognition of the species, and analysis of a series of reliably identified bites, the treatment outcome would be more promising. We aimed to study snakebite patients' clinical profile and treatment outcome in a rural tertiary care setup.

Materials and Method:

This is a retrospective study in which the data evaluated from an epidemiological viewpoint; gender and age of the snake bite victim, time when bitten, interval between the bite and medical consultation, pattern of toxicity, and response to anti-snake venom (ASV).

Results:

Of a total of 200 patients bitten by a snake, 121 were males, with 77% adults. In nearly all cases, the type of snake was unknown; however, most of the bites were poisonous, showing one or the other type of toxicity. One hundred seventy-one patients survived the snake bite, and 29 succumbed. When Logistic regression was done with Death/discharge as the dependent variable and “Time to bite and reaching hospital, Age, Sex, number of ASV given, Ventilation needed or not, pack cell volume (PCV) numbers, Fresh Frozen Plasma (FFP) numbers, Dialysis and presence or absence of toxicity” as the independent variables, the model developed did not account for any respectable amount of variation in the outcome. The only variable found to be predicting the outcome significantly was FFP.

Conclusion:

It is often difficult to identify the type of snake, and thus polyvalent antisnake venom remains the only available treatment resource. Readily available treatment resources, timely intervention, appropriate referral, and close ICU will alleviate mortality.

A Rapid and International Applicable Diagnostic Device for Cobra (Genus Naja) Snakebites

Cobra snakes (genus Naja) are some of the most dangerous snake species in Asia and Africa, as their bites cause severe life-threatening respiratory failure and local tissue destruction, especially in the case of late diagnosis. The differential diagnosis of snakebite envenomation still mainly relies upon symptomatology, the patient’s description, and the experience of physicians. We have designed a rapid test, immunochromatographic test of cobra (ICT-Cobra), which obtained fair results in improving the diagnosis and treatment of Naja (N.) atra snakebites in Taiwan. In this study, we further investigated the feasibility of applying the kit for the detection of other cobra venoms based on the potential interspecies similarity. We firstly demonstrated the cross-reactivity between eight venoms of medically important cobra species and the rabbit anti-N. atra IgG that was used in ICT-Cobra by Western blotting and sandwich enzyme-linked immunosorbent assay. Then, ICT-Cobra was used to detect various concentrations of the eight venoms to elucidate its performance. Noticeable correlations between the cross-reactivity of venoms from genus Naja snakes and existing geographical characteristics were found. ICT-Cobra could detect venoms from other Asian cobras with variable detection limits comparable to those observed for N. atra, but the kit was less successful in the detection of venom from African cobras. The similar but slightly different venom components and the interaction between venom and rabbit anti-N. atra IgG led to variations in the detection limits. The transcontinental usage of ICT-Cobra might be possible due to the cross-reactivity of antibodies and similarities among the larger-sized proteins. This study showed that the close immunological relationships in the genus Naja could be used to develop a venom detection kit for the diagnosis of cobra envenomation in both Asian and African regions. Additional clinical studies and technical adjustments are still needed to improve the efficacy and broadening the application of ICT-Cobra in the future.

Trends in snakebite deaths in India from 2000 to 2019 in a nationally representative mortality study

The World Health Organization call to halve global snakebite deaths by 2030 will require substantial progress in India. We analyzed 2833 snakebite deaths from 611,483 verbal autopsies in the nationally representative Indian Million Death Study from 2001 to 2014, and conducted a systematic literature review from 2000 to 2019 covering 87,590 snakebites. We estimate that India had 1.2 million snakebite deaths (average 58,000/year) from 2000 to 2019. Nearly half occurred at ages 30-69 years and over a quarter in children < 15 years. Most occurred at home in the rural areas. About 70% occurred in eight higher burden states and half during the rainy season and at low altitude. The risk of an Indian dying from snakebite before age 70 is about 1 in 250, but notably higher in some areas. More crudely, we estimate 1.11-1.77 million bites in 2015, of which 70% showed symptoms of envenomation. Prevention and treatment strategies might substantially reduce snakebite mortality in India.

Exploring circulatory shock and mortality in viper envenomation: a prospective observational study from India

BACKGROUND

Viper envenomation contributes to nearly 50% of snake-bite deaths in India, chiefly due to circulatory shock. The mechanisms leading to circulatory shock include bleeding, capillary leak syndrome (CLS) and myocardial depression. Pituitary-adrenal axis involvement in circulatory shock, though described, has not been fully elucidated.

AIM

To identify predictors of circulatory shock and mortality in viper envenomation and explore the role of pituitary-adrenal axis in circulatory shock.

DESIGN

Prospective hospital-based observational study.

METHODS

Once a syndromic diagnosis of viper envenomation was made, relevant clinical and laboratory data were collected. Serum cortisol was estimated in those with circulatory shock. Post-mortem examination of pituitary, kidneys and adrenals was performed. Adjusted odds-ratios were calculated for respective risk-factors for shock and mortality using multivariable logistic regression with backward elimination strategy.

RESULTS

Of 248 patients of viper envenomation treated at our hospital, circulatory shock was present in 19% and in-hospital mortality was 23%. CLS, circulatory shock, bleeding and requirement of > 20 vials of antivenom predicted mortality. Ischaemic and haemorrhagic necrosis of pituitary or adrenals was present in 51% of post-mortem specimens. Disseminated intravascular coagulation (DIC) and CLS were strong predictors of pituitary haemorrhage.

CONCLUSION

Predictors of mortality - bleeding, CLS and requirement of high antivenom doses are warning signs which can alert clinicians to patients who may have poor outcomes. Our study points to a definite role of pituitary-adrenal axis in circulatory shock supports the hypothesis that pituitary involvement in viper envenomation closely resembles Sheehan syndrome. The mechanism of pituitary involvement appears to be a result of increased susceptibility of the swollen gland secondary to CLS and micro thrombi deposition in DIC.

Clinical Condition and Management of 114 Mamushi (Gloydius blomhoffii) Bites in a General Hospital in Japan

Objective Mamushi (Gloydius blomhoffii) snakebite is the most common type of snake injury in Japan and is also seen in China and Korea. Although the components of Mamushi venom have been investigated, epidemiological and clinical descriptions still remain limited in the English literature. The aim of this study was to review the clinical features and management of patients with injuries related to Mamushi snakebites. Methods We conducted a retrospective examination of 114 Mamushi snakebite cases encountered at a general hospital in Japan from January 2004 to November 2016. Data were collected from the medical records. Results We found that Mamushi snakebites commonly occurred during summer and the daytime, with elderly men typically being affected. The symptom grade at initial consultation was significantly worse in the walk-in group than in the ambulance admission group, probably due to treatment delay. The number of fangs that pierced the skin was not related to the severity of the symptoms. The group treated with a tourniquet more frequently exhibited exacerbation of symptoms than those that received other treatments (p<0.001). Conclusion The delay between patients being bitten and arriving at hospital as well as the number of fangs that pierced the skin did not affect the duration of hospitalization; however, proximal tourniquation should be avoided in such cases, as significant exacerbation of local symptoms was observed when this procedure was applied.

Daboia (Vipera) palaestinae envenomation in horses: Clinical and hematological signs, risk factors for mortality and construction of a novel severity scoring system

Daboia palaestinae is the most common venomous snake in Israel and an important cause of envenomations in humans and animals. Although specific antivenom is produced from horses, little documentation exists regarding the characteristics of envenomed horses. This survey was constructed to describe the clinical, hematological and biochemical characteristics of D. palaestinae envenomation in horses, to identify risk factors for fatality and to construct a prognostic snakebite severity scale (SSS) to be used by veterinarians in the field. Data regarding 123 equine snakebite cases were collected over four years. Clinical signs most frequently described were local swelling (100%), tachycardia (67%), increased respiratory effort (62%), bite marks (44%) and reduced appetite (50%). Blood samples were collected at initial presentation from 23 of these horses. Hematological and biochemical abnormalities described in the majority of the sampled cases included leukocytosis (52%), neutrophilia (78%), increased creatine phosphokinase (77%), hypoproteinemia (50%), decreased total carbon dioxide (54%), and hyperphosphatemia (54%). The overall case fatality rate was 20.3% (25/123 horses). Risk factors associated with increased mortality (P < 0.05) were body weight below 200 kg, hind limb envenomation, severity of local swelling, mental status, respiratory effort, bleeding disorders, dehydration, basophilia, monocytosis, bilirubinemia, hypocalcemia and hyperphosphatemia. These risk factors were used to construct an SSS adapted for the assessment of envenomed horses in the field, consisting of seven dichotomous parameters. A cutoff value of 1.5 predicted mortality with 95% sensitivity and 68% specificity. In the future, this tool could assist clinicians with case management and communication with owners.

A retrospective study of use of polyvalent anti-snake venom and risk factors for mortality from snake bite in a tertiary care setting

AIMS

Envenomation with poisonous snakes is associated with considerable morbidity and mortality. The present study was undertaken with the objectives of assessing anti-snake venom (ASV) use, early adverse reactions to ASV, premedication and clinical outcomes in snake bite patients. Association of various risk factors (age, gender, dose of ASV, time gap between snake bite and ASV administration, use of mechanical ventilation and type of snake bite) with mortality was also assessed.

SETTINGS AND DESIGN

This retrospective study was conducted at two Tertiary Care Teaching Hospitals.

SUBJECTS AND METHODS

The medical records of 176 patients of snake bite with documented use of ASV were retrospectively analyzed to retrieve relevant data.

STATISTICAL ANALYSIS

Descriptive statistics was used to express results about ASV use, early adverse reactions to ASV, premedication and clinical outcomes. Univariate and multivariate analysis was performed to find out significant risk factors associated with mortality.

RESULTS

The main indication for ASV was vasculotoxic snake bite (75%) followed by neurotoxic snake bite (16%). Mean dose of ASV was 18.63 ± 14.52 vials. Prophylactic premedication with corticosteroids alone or in combination with antihistaminic was used in more than 70% patients. Early adverse reactions to ASV were seen in 4% patients. Neurotoxic snake bite was a significant risk factor associated with mortality in multivariate analysis.

CONCLUSIONS

Neurotoxic snake bite is an independent predictor of mortality in snake bite patients. Currently used polyvalent ASV may be less effective in treating neurotoxic snake bite.

The North-South divide in snake bite envenomation in India

Snake bite envenomations are common in rural areas and the incidence peaks during monsoons in India. Prominent venomous species have been traditionally labeled as the ‘big four’ that includes Cobra, Krait, Russel's viper and Saw scaled viper. Systematic attempts for identification and classification of prevalent snakes in various states of India are missing till now and there is no concrete data on this aspect. The published literature however shows that some species of snakes are more prevalent in a particular region than the other parts of India e.g. Saw scaled vipers in Rajasthan. We reviewed the published literature from various parts of India and found that there is a North-South divide in the snake bite profile from India. Neurotoxic envenomations are significantly higher in North India compared to South India where Hematotoxic envenomations are prevalent. Russel's viper causes local necrosis, gangrene and compartment syndrome. These manifestations have never been reported in North Indian snake bite profile in the published literature. Early morning neuroparalysis caused by Krait is a common problem in North India leading to high mortality after snake bite. This review presents supporting evidence for the North-South divide and proposes a way forward in formulation and revision of guidelines for snake bite in India.

Mass awareness regarding snake bite induced early morning neuroparalysis can prevent many deaths in North India

Introduction:

In North India snake bite deaths are predominantly seen with neurotoxic envenomations (NEs) whereas in South India the hemotoxic envenomation (HE) is more common. Krait is responsible for most deaths in North India. It bites people sleeping on the floors, mostly at night. We describe the profile of venomous snake bites over 1 year in 2013.

Materials and Methods:

The study was conducted in a rural tertiary care hospital in North India. Demographics, circumstances of bite, envenomation, first aid, delay, consultation, treatment, anti-venom, and outcomes were recorded for all victims of snake bite. We included all consecutive adult (>18 years) venomous snake bite victims admitted from January to December 2013.

Results:

A total of 91 patients with venomous snake bites were included in the study. Pure NEs were 41 (45.1%), pure HE in 31 (34.1%), 7 (7.7%) had mixed NE + HE, and 12 (13.2%) had only local swelling. Forty patients (44%) were bitten during sleep presenting as NE (92.5%), NE + HE (5%), and HE (2.5%). Findings in the 51 patients (56%) bitten during activity were HE (58.8%), local swelling (23.5%), NE + HE (9.8%), and NE (7.8%) (P < 0.0001). First aid was sought by 24 NE patients out of which 23 (96%) went to alternate practitioners or religious healers.

Conclusion:

Almost all (97.5%) bites during sleep resulted in NE in our study. About 96% of NE sought first aid from alternate practitioners or religious healers in hope of some magical treatment. Thus, a deadly combination of krait bite during sleep and wrong health seeking behavior is responsible for high mortality krait bites in this region. Mass public awareness regarding krait bites can prevent mortality in many such cases.

A comparative study of venomics of Naja naja from India and Sri Lanka, clinical manifestations and antivenomics of an Indian polyspecific antivenom

Naja naja (Indian cobra) from Sri Lanka and India is the WHO Category 1 medically important snakes in both countries. Some antivenom produced against Indian N. naja (NNi) were less effective against Sri Lankan N. naja (NNsl). Proteomes of NNi and NNsl venoms were studied by RP-HPLC, SDS-PAGE and LC/MS/MS. Six protein families were identified in both venoms with the most abundant were the 3 finger toxins (3FTs) where cytotoxins (CTX) subtype predominated, followed by phospholipase A2, cysteine-rich venom protein, snake venom metalloproteases, venom growth factors, and protease inhibitors. Qualitative and quantitative differences in the venomics profiles were observed. Some proteins were isolated from either NNi or NNsl venom. Postsynaptic neurotoxins (NTX) were identified for the first time in NNsl venom. Thus, there are geographic intra-specific variations of venom composition of the two N. naja. The relative abundance of CTX and NTX explained well the clinical manifestations of these venoms. Antivenomics study of an Indian antivenom (Vins) showed the antibodies effectively bound all venom toxins from both snakes but more avidly to the Indian venom proteins. The lower antibody affinity towards the 'heterologous' venom was the likely cause of poor efficacy of the Indian antivenom used to treat NNsl envenoming.

Older Age and Time to Medical Assistance Are Associated with Severity and Mortality of Snakebites in the Brazilian Amazon: A Case-Control Study

The Amazon region reports the highest incidence of snakebite envenomings in Brazil. We aimed to describe the epidemiology of snakebites in the state of Amazonas and to investigate factors associated with disease severity and lethality. We used a nested case-control study, in order to identify factors associated with snakebite severity and mortality using official Brazilian reporting systems, from 2007 to 2012. Patients evolving to severity or death were considered cases and those with non-severe bites were included in the control group. During the study period, 9,191 snakebites were recorded, resulting in an incidence rate of 52.8 cases per 100,000 person/years. Snakebites mostly occurred in males (79.0%) and in rural areas (70.2%). The most affected age group was between 16 and 45 years old (54.6%). Fifty five percent of the snakebites were related to work activities. Age ≤15 years [OR=1.26 (95% CI=1.03-1.52); (p=0.018)], age ≥65 years [OR=1.53 (95% CI=1.09-2.13); (p=0.012)], work related bites [OR=1.39 (95% CI=1.17-1.63); (p<0.001)] and time to medical assistance >6 hours [OR=1.73 (95% CI=1.45-2.07); (p<0.001)] were independently associated with the risk of severity. Age ≥65 years [OR=3.19 (95% CI=1.40-7.25); (p=0.006)] and time to medical assistance >6 hours [OR=2.01 (95% CI=1.15-3.50); (p=0.013)] were independently associated with the risk of death. Snakebites represent an occupational health problem for rural populations in the Brazilian Amazon with a wide distribution. These results highlight the need for public health strategies aiming to reduce occupational injuries. Most cases of severe disease occurred in the extremes of age, in those with delays in medical attention and those caused by Micrurus bites. These features of victims of snakebite demand adequate management according to well-defined protocols, including prompt referral to tertiary centres when necessary, as well as an effective response from surveillance systems and policy makers for these vulnerable groups.

Clinico-Epidemiological Profile of Snakebite Cases Admitted in a Tertiary Care Centre in South India: A 5 Years Study

OBJECTIVES

This study was conducted to assess the clinic-epidemiological profile of snakebite cases admitted at a Tertiary Care Centre in South India.

MATERIALS AND METHODS

A record based retrospective study was carried out at Kasturbha Medical College affiliated hospitals in Mangalore. All the snakebite cases admitted to the hospitals from January 2007 to December 2011 were included in the study. Data were collected using a pretested semi-structured questionnaire and analyzed using Statistical Package for Social Sciences (SPSS version 11.5). The results are expressed as percentages.

RESULTS

The study included 198 cases of snakebite victims. The majority of the cases were males (68.2%). The mean age of the study population was 34.8 years. Maximum numbers of snakebite cases were reported during the month of September to December (47.9%). The peak time of snakebite was between 18.01 and 24.00 h which was reported in 40.5% of the cases. Lower extremities were the most common site of bite in more than three-fourth of the cases (80.9%). The most common symptoms were a pain (45.9%) and swelling (44.9%). The case fatality rate was observed to be 3.0%.

CONCLUSION

Snakebite still remains a major public health problem in this part of the world. Knowledge must be imparted regarding the prevention of snakebites through community health programs. Messages regarding prompt reporting of such cases and importance of effective treatment must be disseminated among people through mass media and role plays.

Protein content of antivenoms and relationship with their immunochemical reactivity and neutralization assays

CONTEXT

Therapy for snakebites relies on the application of antivenoms, which may be produced with different immunogenic mixtures of venom and possess different pharmaceutical characteristics. For these reasons, immunological cross-reactivity and heterologous neutralization were analyzed relative to the protein content of three antivenoms used in the Americas.

METHODS

The antivenoms studied were composed of equine F(ab')2 fragments from animals immunized with Crotalinae venoms. The antivenoms were tested against venoms of seven pit viper species from Argentina, seven from Mexico, one from Costa Rica, and one from Colombia.

RESULTS

Immunoblotting showed high cross-reactivity of all major protein bands with all the antivenoms tested. ELISA results also showed high cross-reactivity among the different venoms and antivenoms, and a high heterologous neutralization was observed. The results can be interpreted in different ways depending on whether the reactivity is considered in terms of the volume of antivenom used or by the amount of protein contained in this volume of antivenom. The antivenoms with high immunochemical reactivity and neutralizing capacity were those with higher protein content per vial; but when doses were adjusted by protein content, antivenoms of apparently lower neutralizing capacity and immunochemical reactivity showed at least similar potency and reactivity although volumetrically at higher doses.

CONCLUSION

Protein content relative to neutralization potency of different products must be taken into account when antivenoms are compared, in addition to the volume required for therapeutic effect. These results show the importance of obtaining high-affinity and high-avidity antibodies to achieve good neutralization using low protein concentration and low-volume antivenoms.

Early Treatment with Intranasal Neostigmine Reduces Mortality in a Mouse Model of Naja naja (Indian Cobra) Envenomation

Objective. Most snakebite deaths occur prior to hospital arrival; yet inexpensive, effective, and easy to administer out-of-hospital treatments do not exist. Acetylcholinesterase inhibitors can be therapeutic in neurotoxic envenomations when administered intravenously, but nasally delivered drugs could facilitate prehospital therapy for these patients. We tested the feasibility of this idea in experimentally envenomed mice. Methods. Mice received intraperitoneal injections of Naja naja venom 2.5 to 10 times the estimated LD50 and then received 5 μL neostigmine (0.5 mg/mL) or 5 μL normal saline by nasal administration. Animals were observed up to 12 hours and survivors were euthanized. Results. 100% of control mice died. Untreated mice injected with 2.5× LD50 Naja naja died at average 193 minutes after injection, while 10 of 15 (67%) of treated mice survived and were behaviorally normal by 6 hours (P < 0.02). In the 5× LD50 group, survival was prolonged from 45 minutes to 196 minutes (P = 0.01) and for 10× LD50 mice, survival increased from 30 to 175 minutes (P < 0.02). Conclusion. This pilot suggests that intranasal drugs can improve survival and is the first direct demonstration that such an approach is plausible, suggesting means by which treatment could be initiated before reaching the hospital. Further investigation of this approach to neurotoxic and other types of envenomation is warranted.

Rapid diagnosis of Naja atra snakebites

BACKGROUND

The clinical diagnosis of snakebites is critical and necessary in many parts of the world, especially in Southeastern Asia, where venomous snakebites are a burden on public health. It is difficult to define or recognize the species of venomous snake because of the overlapping clinical manifestations of envenomations. A quick and reliable method for identifying the snake species is necessary. We designed and tested a strip of lateral flow system for the diagnosis of cobra snake bites in Taiwan.

METHODS

We developed a kit based on an immunochromatographic method for rapid detection of cobra (Naja atra) venom in human serum. The test and control lines composed of 1 mg/ml polyclonal duck antivenom and 0.5 mg/ml goat anti-rabbit immunoglobulin antibody solutions, respectively, were coated on nitrocellulose strips. Colloidal gold was conjugated with rabbit polyclonal anti-cobra venom antibodies. From July 2007 to December 2012, we used the kit to test serum from snakebite patients and to examine the agreement between our rapid test and the currently used sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our kit was able to detect cobra venom in serum samples in 20 minutes with a detection limit of 5 ng/ml. An absence of cross-reactivity with other non-cobra venoms from Taiwan was noted in vitro. A total of 88 snakebite patients (34 cobra and 54 other non-cobra) were tested. The sensitivity of the strips based on the ELISA results was 83.3% and the specificity was 100%. There was a strong agreement between the results of the ELISA and immunochromatographic strips (κ = 0.868).

DISCUSSION AND CONCLUSIONS

This data indicates that an immunochromatographic strip might be suitable for cobra venom detection and could be used as a quick diagnostic tool in cases of N. atra snakebite.

Snakebite profile from a medical college in rural setting in the hills of Himachal Pradesh, India

Objective:

The objective of the following study is to assess the clinical profiles and manifestations of snakebite patients in the rural hilly setting of Shivalik and the Lesser Himalayan region of Himachal Pradesh.

Materials and Methods:

A hospital record-based retrospective descriptive study was carried out that included details on demography, clinical profile, treatment and outcome among 200 patients over a period of 2 years. The data was analyzed using Chi-square test for comparison.

Results:

142 (71%) patients were young (age group of 16-45 years) and the number of male patients was 118 (59%) and female patients were 82 (41%). All the cases recorded presented in the months of April to November. Not a single case was recorded from December to March. The most frequently bitten sites were the lower limbs particularly the feet. 86 (43%) of the patients presented without any features of envenomation. Neuroparalysis was the commonest presentation in 53 (46%) patients followed by hemotoxicity in 36 (31%) among symptomatic patients. Early morning neuroparalysis syndrome was the presentation in 26.4% patients. Allergic reactions in the form of early anaphylaxis were noted in 7% patients.

Conclusion:

Snake bite is a neglected tropical disease affecting poor villagers in rural areas. Future research focusing on understanding epidemiological determinants of snake bite is desired.

Clinical features and treatment experience: a review of 292 Chinese cobra snakebites

Although Chinese cobra snakebite is the most common type of snake venenation in China, it still lacks a comprehensive and systematic description. Hence, we aimed to study Chinese cobra bite cases with particular attention to demography, epidemiology and clinical profile. In this study, a total of 292 cases of Chinese cobra snakebite, presenting between January 1, 2008 and December 31, 2012, were retrospectively reviewed. To investigate the effect of treatment at different presentation times (time from snakebite to admission), the patients were divided into two groups: group A included 133 cases that presented <12 h after the bite; group B included 159 cases that presented ≥12 h after the bite. To assess the correlation between application of a tourniquet and skin grafting, the cases were re-divided into two groups according to whether or not a tourniquet was used after the snakebite: tourniquet group (n=220) and non-tourniquet group (n=72). The results showed that Chinese cobra snakebites were most commonly seen during the summer, in the upper limbs, and in males, young adults, and snake-hunters. Group A experienced milder intoxication than group B (P<0.001). The rate of skin grafting was significantly higher in the tourniquet group (20.0%, compared with 9.7% in the non-tourniquet group, P<0.05). The results of this study indicate that anti-cobra venom and swift admission (within 12 h of the snakebite) are recommended for Chinese cobra snakebite. Tourniquet use is not recommended.