Adverse drug reaction profile of anti-snake venom in a rural tertiary care teaching hospital

The Role of Snake Venom Proteins in Inducing Inflammation Post-Envenomation: An Overview on Mechanistic Insights and Treatment Strategies

The intricate combination of organic and inorganic compounds found in snake venom includes proteins, peptides, lipids, carbohydrates, nucleotides, and metal ions. These components work together to immobilise and consume prey through processes such as paralysis and hypotension. Proteins, both enzymatic and non-enzymatic, form the primary components of the venom. Based on the effects they produce, venom can be classified as neurotoxic, hemotoxic, and cytotoxic. Studies have shown that, after envenomation, proteins in snake venom also contribute significantly to the induction of inflammatory responses which can either have systemic or localized consequences. This review delves into the mechanisms by which snake venom proteins trigger inflammatory responses, focusing on key families such as phospholipase A2, metalloproteinases, serine proteases, C-type lectins, cysteine-rich secretory proteins, and L-amino acid oxidase. In addition, the role of venom proteins in activating various inflammatory pathways, including the complement system, inflammasomes, and sterile inflammation are also summarized. The available therapeutic options are examined, with a focus on antivenom therapy and its side effects. In general, this review offers a comprehensive understanding of the inflammatory mechanisms that are triggered by snake venom proteins and the side effects of antivenom treatment. All these emphasize the need for effective strategies to mitigate these detrimental effects.

Supplementation of polyclonal antibodies, developed against epitope-string toxin-specific peptide immunogens, to commercial polyvalent antivenom, shows improved neutralization of Indian Big Four and Naja kaouthia snake venoms

Snakebites profoundly impact the rural population of tropical nations, leading to significant socio-economic repercussions. Polyvalent antivenom (PAV) therapy faces several limitations, including intra-specific variations and poor efficacy against some major toxins and low molecular mass, poorly immunogenic toxins, which contribute to increased mortality and morbidity rates. Innovative strategies for developing novel antivenoms are continuously explored to address these challenges. The present study focuses on designing of 17 epitope-string toxin-specific peptide immunogens from pharmacologically active major and/or poorly immunogenic toxins (snake venom metalloprotease, Kunitz-type serine protease inhibitor, phospholipase A2, three-finger toxin) from the venom of the 'Big Four' venomous snakes and Naja kaouthia (NK) in India. These custom peptide antibodies demonstrated robust immuno-reactivity against the venoms 'Big Four' and NK. When these antibodies were supplemented with commercial PAV at a defined ratio (formulated polyvalent antivenom or FPAV), it significantly enhanced the neutralization of snake venom enzymes and in vivo neutralization of lethality and pharmacological activities such as haemorrhage, necrosis, pro-coagulant, defibrinogenation, and myotoxicity of 'Big Four' and NK venoms compared to PAV in mice. The present study highlights a promising strategy for developing next-generation antivenoms using synthetic peptide-based immunogens, offering a targeted approach to address the limitations of current antivenom therapy.

Exploring the inhibitory potential of phytochemicals from Vernonia glaberrima leaves against snake venom toxins through computational simulation and experimental validation

Phospholipase A2 (PLA2) is an enzyme present in appreciable quantity in snake venoms which catalyze the hydrolysis of glycerophospholipids at sn-2 position and promote the release of lysophospholipids and fatty acids. 5-methylcoumarin-4-β-glucoside (5MC4BG) and lupeol were previously isolated from the leaves of V. glaberrima. The aim of this research was to evaluate effect of these compounds as potential inhibitors of snake venom toxins of Naja nigricollis using an in vitro and in silico studies. Antisnake venom studies was conducted using acidimetry while the molecular docking analysis against PLA2 enzyme from N. nigricollis was performed using Auto Dock Vina and ADME-Tox analysis was evaluated using swissADME and ProTox-II online servers. The two compounds (5MC4BG and Lupeol) were able to inhibit the hydrolytic actions of PLA2 enzyme with percentage inhibition ranging from 23.99 to 72.36 % and 21.97-24.82 % at 0.0625-1.00 mg/mL respectively while the standard ASV had 82.63 % at 1.00 mg/mL after 10 min incubation at 37 °C. Similar effects were observed after 30 min incubation, although there was significant increase in percentage inhibition of 5MC4BG and lupeol ranging from 66.51 to 83.73 % and 54.87-59.60 % at similar concentrations. Furthermore, the compounds were able to bind to the active site of PLA2 enzyme with high affinity (-7.7 to -6.3 kcal/mol); the standard ligand, Varespladib had a docking score of -6.9 kcal/mol and they exhibited favorable drug-likeness and pharmacokinetic properties and according to toxicity predictions, the two compounds are toxic. In conclusion, the leaf of V. glaberrima contains phytoconstituents with antisnake activity and thus, validates the hypothesis that, the phytoconstituents of V. glaberrima leaves has antisnake venom activity against N. nigricollis venom and thus, should be studied further for the development as antisnake venom agents.

A Nationwide Study on the Risks of Complications and Healthcare Costs of Snakebite Envenomation in Taiwan

In Taiwan, six medically important venomous snakes, Trimeresurus stejnegeri stejnegeri, Protobothrops mucrosquamatus, Deinagkistrodon acutus, Daboia siamensis, Naja atra, and Bungarus multicinctus, are found. However, comprehensive research on the complications and associated healthcare costs of snakebite envenomation (SBE) is lacking. We retrospectively analyzed pertinent information from the Taiwan National Health Insurance Research Database dated January 2002 to December 2014. We investigated the risk factors for complications and their impact on healthcare costs. Among the 12,542 patients with SBE, those from N. atra or B. multicinctus were more likely to experience wound infections and neurological complications than were those from T. s. stejnegeri or P. mucrosquamatus. In addition, being female, being elderly, and having a Charlson Comorbidity Index equal to or greater than 3 points were associated with an increased likelihood of wound infections and psychological complications. The annual national economic burden averaged US$1,083,624, with an average healthcare cost of US$1,129 per SBE. Snakebite envenomations from N. atra or B. multicinctus, as well as various complications, resulted in significantly higher costs. It is crucial to comprehend the risk factors for complications and their role in increasing expenses to provide insight for tailored healthcare interventions, mitigate complications, and reduce the economic burdens associated with SBEs.

A rare manifestation of serum sickness after common krait envenomation in a patient treated with polyvalent anti-snake venom in India: Presentation and challenges

Envenomation from snakebites is a significant public health concern in the Southeast Asian region resulting in considerable mortality and morbidity. Anti-snake venom (ASV) despite being the only rescue can bring forth several acute and delayed adverse effects. Among them, serum sickness is a late manifestation after treatment with ASV that presents after 5-14 days of treatment. However, there is no specific definition to diagnose serum sickness or proven treatment. Here, we present a case of serum sickness to provide an insight into this unventured zone, briefing the presentation, treatment and probable reason for serum sickness and its prevention after common krait envenomation and treatment with polyvalent ASV in India.

An indigenously developed tele-ICU model to treat severe cases of envenomation in remote regions in India

In cases of severe envenomation due to snakebites, patients require antivenom, intensive care management, including respiratory support, haemodynamic monitoring and renal replacement therapy. Early recognition and treatment of complications such as acute kidney injury, rhabdomyolysis and coagulopathy are important to improve outcomes.Tele-ICU models can play a critical role in providing access to critical care expertise and nuanced support to remote healthcare facilities that may not have the necessary resources or expertise to manage complex cases of envenomation. With the help of telemedicine technology, remote intensivists can provide timely guidance on diagnosis and ongoing management, improving the quality of care and outcomes for patients. We discuss two patients in resource-constrained regions of India with severe envenomation who were managed with tele-ICU support.

Kounis syndrome after anti-snake venom intradermal skin test: A case report

Snake bites are a concerning health problem in Egypt and other tropical countries that are effectively managed with anti-snake venom (ASV). ASV has common reactive complications that are usually mild. Rarely, anaphylaxis and severe systemic reactions may occur following ASV. In this case report, we present a rare condition of Kounis syndrome, acute allergic myocardial infarction, in a young man during anaphylaxis following an allergic intradermal test of VACSERA snake antivenom.

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.

Augmented rescue of macroglobulins by supplementation of anti-snake venom with methanolic extract of Andrographis paniculata in Naja naja envenomation

Proteins of the macroglobulin family are prime targets of venom enzymes in snake bite. A massive reduction in the active concentration of these multifunctional proteins in snake bite, makes the living system vulnerable to dysregulation. This study investigates the ability of Indian polyvalent anti-snake venom (ASV), methanolic extract of Andrographis paniculata (MAP) and their combination in rescuing human alpha 2-macroglobulin (A2MG) and its homologues in rat plasma, from inactivation by Naja naja (N.N) venom enzymes. In-vitro experiments were conducted with heparinized human plasma and in-vivo experiments with female Wistar rats. Along with appropriate controls, there were 3 test groups in in-vitro and 8 test groups in in-vivo experiments. The in-vitro test groups were exposed to N.N venom for zero, 30 or 90 min prior to incubation with ASV or MAP or reduced ASV supplemented with MAP and incubated for 16 h at 37 °C. Chymotrypsin-bound esterase (CTBE) activity of A2MG was estimated. Rats were administered the venom intramuscularly and treated with ASV/MAP/ASV + MAP. CTBE activity of macroglobulin homologues was measured on day 1, 7 and 14. Survival of animals was noted. In human plasma, addition of ASV or MAP or ASV + MAP prevented loss of A2MG activity maximally to the extent of 88–100% (p = 0.001). In rats, reduced concentration of ASV supplemented with MAP showed complete rescue of macroglobulin homologues and 90% survival. The compulsive evidence from this study, underscores the merits of using this multipronged strategy in rescuing the macroglobulins and improving survival in envenomation due to N.N.

Early Adverse Reactions to Snake Antivenom: Poison Center Data Analysis

Antivenom is an essential treatment for snake envenomation; however, early adverse reactions (EARs) are major limitations to its use. We performed a retrospective cross-sectional study using Ramathibodi Poison Center data (January 2016 to December 2017) to clarify the incidence and severity of EARs following different F(ab’)2 antivenoms. Among 1006 envenomed patients, 684 (68%) received antivenom therapy with a total of 1157 doses, mostly green pit viper antivenom. The overall EAR incidence and rate were 22. 5% (154/684) and 15% (173/1157), respectively. The EAR rate following each type of antivenom was >10%, except for Russell’s viper antivenom (2.9%); the severe reaction rate was 2.6% (30/1157). Malayan pit viper bites caused a high incidence of EARs (37.8%) and the highest EAR rate (22.3%). Fifty-two cases developed anaphylaxis. All EARs occurred within 2 h after treatment initiation. No deaths were attributed to EARs. The duration of administration was significantly different between doses of antivenom that induced EARs and those that did not. In conclusion, all types and every dose of antivenom should be infused for 30−60 min. Preparation of resuscitation equipment and continuous clinical observation are crucial for at least 2 h after administration, and prompt treatment should be provided when EARs occur.

Prevention and improvement of clinical management of snakebite in Southern Asian countries: A proposed road map

In the Southern Asian countries, snakebite takes a substantial toll in terms of human life, inflicts acute morbidity and long term disability both physical and psychological, and therefore represents a neglected socio-economic problem and severe health issue that requires immediate medical attention. The 'Big Four' venomous snakes, viz. Daboia russelii, Naja naja, Bungarus caeruleus and Echis carinatus, are prominent, medically important species and are the most dangerous snakes of this region; therefore, the commercial polyvalent antivenom (PAV) contains antibodies against the venoms of these snakes. However, envenomations by species other than the 'Big Four' snakes are grossly neglected, and PAV is only partially effective in neutralizing the venom of these snakes. Many issues confounding effective treatment of snakebite are discussed in this review, and these hurdles preventing successful treatment of snakebite must be addressed. However, in South Asian countries, the pre-hospital treatment and appropriate first aid are equally important to mitigate the problem of snakebite and therefore, these issues are also highlighted here. Further, this review suggests a roadmap and guidelines for the prevention of snakebite and improvement of hospital management of snakebite in these Southern Asian countries.

Evaluation of the merit of the methanolic extract of Andrographis paniculata to supplement anti-snake venom in reversing secondary hemostatic abnormalities induced by Naja naja venom

Increasing evidence suggests a sizable involvement of hemotoxins in the morbidity associated with envenomation by the Indian spectacled cobra, Naja naja (N.N). This study investigates the ability of Indian polyvalent anti-snake venom (ASV), methanolic extract of Andrographis paniculata (MAP) and their combination in reversing the hemostatic abnormalities, viz. activated partial thromboplastin time(aPTT), prothrombin time(PT) and thrombin time(TT) in citrated plasma. These parameters were assessed in 2 groups of experiments. Group 1: Without the prior incubation of plasma with venom and Group 2: With prior incubation of plasma with venom for 90 min at 37°C. Venom caused significant (p < 0.001) prolongation in aPTT (175%), PT (49%) and TT (34%) in Group 1 and ASV could completely bring them back to normal. MAP showed a concentration-dependent reversal in aPTT, normalization of PT and prolongation of TT. When low concentration of ASV was supplemented with MAP, their combined effect in normalizing aPTT and PT improved by 37% and 26% respectively when compared to ASV alone. In Group 2, venom caused significant (p < 0.001) prolongation in aPTT (231%), PT (312%) and TT (245%). ASV had limited effect in reversing aPTT (52%), TT (31%) but completely normalized PT. MAP was marginally effective in reversing the prolonged aPTT and PT but caused further prolongation of TT. Combination of ASV and MAP was more effective than ASV alone in reversing venom-induced increase in aPTT (52%) and PT (29%). The study proved that, a drastic reduction of ASV by 70%, could be effectively supplemented by MAP in combating hemostatic abnormalities induced by NN venom.

Assessment of snakebite burdens, clinical features of envenomation, and strategies to improve snakebite management in Vietnam

The sheer paucity of scientific documentation of herpetofauna in Vietnam and the rudimentary healthcare response to snakebite have stimulated this review. Over six decades of data culled from public data bases and search engines, have been used to assess snakebite burdens, clinical features of envenomation, and strategies for snakebite management in Vietnam. In addition, biochemical and proteomic analyses to decipher venom composition, rapid analytical techniques to be used for clinical diagnosis of snakebite in Vietnam have been discussed in detail. The assessment of efficacy, safety, and quality of commercial antivenom produced in Vietnam and improvement of antivenom production to meet the national requirement has been critically examined. It is apparent that snake bite incidence in Vietnam is exacerbated by mismatch in demand and supply of antivenom therapy, insufficient medical facilities, preference for traditional healers and poor management of clinical records. The impediments arising from geographical and species-specific variation in venom composition can be overcome by the 'Omics approach', and scientific documentation of pathophysiological manifestations post envenomation. The development of next generation of therapeutics, encouraging clinical research, novel approaches and social awareness against snakebite and its treatments have been suggested to significantly reduce the snakebite mortality and morbidity in this region.

Evaluation of Allergic Reactions Following Intravenous Infusion of Polyvalent Antivenom in Snakebite Patients

BACKGROUND

Antivenom is a gold-standard treatment for snakebite envenoming. However, adverse reactions to snake antivenom are common in many parts.

OBJECTIVE

The aim of this study was to evaluate the allergic reactions following intravenous administration of antivenom sera.

METHODS

This was retrospective study, conducted snakebites patients referred to the Rahimi Hospital in Khorramabad. The files of these patients were accessed for demographic data, snakebite-related data, treatment provided, clinical presentation and allergic reaction status as a result of antivenom treatment.

RESULTS

141 cases were investigated including 73.8% male and 26.2% female patients. The mean age of the patients was 38.1±17.1years. Age group 30-39 years accounted for highest number of snakebite cases (24.1%). A majority of victims (89.4%) were from the rural areas. Most of the patients (51.8%) were bitten in the spring and highest number of snakebite were reported in May (39.1%). The most common site of snakebite was lower extremities (50.4%) and upper extremities (44.7%). Among clinical feature of snakebite, pain was the most prevalent in 135 cases (95.7%) followed by swelling (83.7%). The mean antivenom vials used were 6.5±3.7 vials. Allergic reactions occurred in 6 patients (4.26%); reactions were mild in 5 patients and sever in 1patient. The commonest presentation was maculopapular rash (1.4%) and the least common were headache (0.71%), nausea (0.71%), fever (0.71) and hypotension (0.71%).

CONCLUSION

Snakebite is one of the significantlife-threatening environmental events.Immediate antivenom treatment can reduce mortality however, patients should be carefully monitored for adverse allergic reactions.

Health professionals' overestimation of knowledge on snakebite management, a threat to the survival of snakebite victims-A cross-sectional study in Ghana

Background

According to the World Health Organization, snakebites, a common occupational hazard in developing countries accounts for an annual loss of between 81,000 and 138, 000 lives following 5 million bites of which 2.7 million results in envenomation. Since snakebite-associated morbidity and mortality are more prevalent in agricultural economies such as Ghana, health professionals should be optimally knowledgeable on how to manage the incidence of snakebites. Lack of knowledge or overestimation of a professional's knowledge can affect heath delivery especially for emergencies such as snakebites. The three rurally situated Tongu districts in South-Eastern Ghana with agriculture as the major source of livelihood for their inhabitants, are prone to snakebites. This study, therefore, brings up the need to assess whether the health professionals in these districts are well-equipped knowledge-wise to handle such emergencies and whether they can rightly estimate their knowledge with regards to snakebite management.

Methodology/Principal findings

Data was collected using a de novo semi-structured questionnaire administered through google form whose link was sent via WhatsApp to 186 health workers made up of nurses, midwives, physician assistants, medical doctors, pharmacists, and pharmacy technicians. This data was analyzed using Statistical Package for the Social Sciences (SPSS) Version 25. Association between variables was determined using the appropriate tools where necessary, using a confidence interval of 95% and significance assumed when p ≤ 0.05. This study found male health workers significantly more knowledgeable about snakebite management (11.53±5.67 vs 9.64±5.46; p = 0.022) but it was the females who overestimated their knowledge level (27.9% vs 24.1%). The medical doctors exhibited the best knowledge on snakebite management with the registered general nurses least knowledgeable. Although most professionals overestimated their knowledge, the registered general nurses were the worst at that (53.7%). Overall knowledge of health care professionals on snakebite management was below average [10.60±5.62/22 (48.2%)] but previous in-service training and involvement in the management of snakebite were associated with better knowledge. Respondents who had no previous training overestimated their knowledge level compared to those who had some post-qualification training on snakebite management (38.1% vs 7.5%). The greatest knowledge deficit of respondents was on the management of ASV associated adverse reactions.

Conclusion

Health workers in rural Ghana overestimated their knowledge about snakebite management although their knowledge was low. Training schools, therefore, need to incorporate snakebite management in their curriculum and health authorities should also expose health workers to more in-service training on this neglected tropical disease.

World Health Organization estimates that every year between 81,000 and 138,000 die due to snake bites across the world. Mismanagement of snakebites can result in increased disabilities and death if not handled by knowledgeable health workers. This study assessed if various categories of health workers made up of professionals from the medical, pharmaceutical, and nursing categories in the three neighbouring Tongu districts in Ghana have the appropriate level of knowledge on snakebite management. Using a newly developed questionnaire, data were collected from the respondents using google forms sent to their WhatsApp platforms. Data were then analyzed using Statistical Package for the Social Sciences (SPSS) Version 25. Results were presented in the form of tables and association between the variables also determined. The level of knowledge of sampled health workers on snakebite was below average, especially among nursing professionals. However, those who had some previous post-qualification training on snakebite management exhibited a significant superior knowledge and least overestimated their knowledge hence policymakers should through workshops equip health workers especially the nurses on snakebites so that rural dwellers whose health care needs are mainly attended to by nurses can be better managed when they suffer snakebites.

Protein decomplexation and proteomics: A complementary assessment method of the physicochemical purity of antivenom

The quality of antivenom is governed by its safety and efficacy profiles. These quality characteristics are much influenced by the purity of antivenom content. Rigorous assessment and meticulous monitoring of antivenom purity at the preclinical setting is hence crucial. This study aimed to explore an integrative proteomic method to assess the physicochemical purity of four commercially available antivenoms in the region. The antivenoms were subjected to Superdex 200 HR 10/30 size-exclusion fast-protein liquid chromatography (SE-FPLC). The proteins in each fraction were trypsin-digested and analyzed by nano-ESI-liquid chromatography-tandem mass spectrometry (LC-MS/MS). SE-FPLC resolved the antivenom proteins into three major protein components of very high (>200 kDa), high (100-120 kDa) and medium (<60 kDa) molecular weights. The major components (80-95% of total proteins) in the antivenoms were proteins of 100-120 kDa consisting of mainly the light and partially digested heavy immunoglobulin chains, consistent with F(ab')₂ as the active principle of the antivenoms. However, LC-MS/MS also detected substantial quantity of large proteins (e.g. alpha-2-macroglobulins), immunoglobulin aggregates and impurities e.g. albumins in some products. The method is practical and able to unveil the quantitative and qualitative aspects of antivenom protein compositions. It is therefore a potentially useful preclinical assessment tool of antivenom purity.

Serious Adverse Reactions to Anti-snake Venom in Children with Snake Envenomation: An Underappreciated Contributor to Snakebite Mortality?

Background

Deaths due to snakebites and serious adverse reactions to anti-snake venom (ASV) are both underreported in India. Serious adverse reactions to ASV are common, contributing significantly to mortality and morbidity. We conducted a study to determine the frequency of occurrence of severe adverse reactions to ASV in children and study the various risk factors and their outcomes.

Patients and methods

We carried out a retrospective record review of all children of snake envenomation admitted in our tertiary care teaching hospital, from January 2013 to December 2016. Children aged 0 to 12 years admitted for snake envenomation and who received ASV as part of their treatment were included. Details about their management, including ASV usage and any adverse effects noted, were collected on a standard data collection form.

Results

Sixty-eight children were enrolled. Hemotoxic (52.9%) envenomation was more common than neurotoxic (35.2%). Severe adverse reactions were present in 42.6%, hypotension in 38.2%, and bronchospasm in 4.4% of the children. The overall mortality rate was 16.1%, anaphylaxis to ASV contributing to 36.3% of them. Mortality was significantly higher in cases with severe adverse reactions (p = 0.005). ASV reactions were also significantly different with different manufacturers.

Conclusions

There is a high frequency of occurrence of severe adverse reactions to ASV resulting in significant morbidity and mortality.

How to cite this article

Hooda R, Parameswaran N, Subramanian M. Serious Adverse Reactions to Anti-snake Venom in Children with Snake Envenomation: An Underappreciated Contributor to Snakebite Mortality? Indian J Crit Care Med 2021;25(6):720-723.

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.

Can the methanolic extract of Andrographis paniculata be used as a supplement to anti-snake venom to normalize hemostatic parameters: A thromboelastographic study

ETHNOPHARMACOLOGICAL RELEVANCE OF ANDROGRAPHIS PANICULATA

The whole plant (including leaves and roots) is used in traditional Ayurveda and Siddha medicine to treat various clinical conditions such as fever, respiratory tract infections, colic pain, liver disorders, diabetes, hypertension, and inflammation. It is also used as an antidote for snake-bite, poisonous bites of insects and recommended as a dietary supplement to boost immunity.

AIM OF THE STUDY

In-vitro thromboelastographic evaluation of the efficacy of methanolic extract of Andrographis paniculata (MAP) and polyvalent anti-snake venom (ASV) in neutralizing the Naja naja (N.N) venom-induced changes in hemostatic parameters.

MATERIALS AND METHODS

Thromboelastographic evaluation of hemostatic parameters was initiated by adding 3μg N.N venom to citrated whole blood from healthy volunteers. The effect of different concentrations of ASV and MAP in neutralizing the toxicity of N.N venom were studied in two groups. In group 1 experiments, citrated whole blood (340μl) was mixed with N.N venom (3μg), immediately followed by successive addition of ASV (5μl, 8μl and 15μl) or MAP (15μg, 30μg, 60μg and 120 μg) or combination of ASV and MAP (3μl ASV+30μg MAP and 3μl ASV+60μg MAP). In group 2 experiments, N.N venom was incubated with whole blood for 90 minutes at 37°C, followed by successive addition of ASV (5μl, 10μl, and 15μl) or MAP (30μg and 60μg) or combination of ASV and MAP (5μl ASV+30μg MAP and 5μl ASV+60μg MAP).

RESULT

In Group 1 experiments, N.N venom caused significant (p<0.05) increase in R-time, K-time, LY30% and a decrease in angle and MA. Optimum effect on hemostatic parameters was observed at a concentration of 8μl ASV, where all the deleterious effects of the venom were completely reversed. Similarly, the addition of MAP to the assay system could reproduce results as ASV, in reversing the deleterious effects of the venom. This occurred in a concentration-dependent manner, from 15μg-60μg, with the optimum results at 60μg. When ASV concentration was reduced to 3μl and supplemented with MAP (30μg or 60μg), the positive supplementary effect of MAP was demonstrated. In Group 2 experiments, N.N venom caused significant (p<0.05) changes in all TEG parameters, with most deleterious changes observed in MA and LY30% compared to Group 1 experiments. ASV when added in increasing concentrations (5-15μl), had beneficial effects only on K-time, angle, and MA. When added together with ASV, MAP (30μg or 60μg) could significantly (p<0.05) supplement the effect of ASV (5μl) in improving R-time, K-time, and angle.

CONCLUSION

This in-vitro study demonstrates the effectiveness of MAP as a supplement to ASV in combating the deleterious effects of N.N venom on hemostasis. However, further in-vivo experiments in animal models are required to substantiate these effects.

Antivenom Neutralization of Coagulopathic Snake Venom Toxins Assessed by Bioactivity Profiling Using Nanofractionation Analytics

Venomous snakebite is one of the world's most lethal neglected tropical diseases. Animal-derived antivenoms are the only standardized specific therapies currently available for treating snakebite envenoming, but due to venom variation, often this treatment is not effective in counteracting all clinical symptoms caused by the multitude of injected toxins. In this study, the coagulopathic toxicities of venoms from the medically relevant snake species Bothropsasper, Calloselasmarhodostoma, Deinagkistrodonacutus, Daboiarusselii, Echiscarinatus and Echisocellatus were assessed. The venoms were separated by liquid chromatography (LC) followed by nanofractionation and parallel mass spectrometry (MS). A recently developed high-throughput coagulation assay was employed to assess both the pro- and anticoagulant activity of separated venom toxins. The neutralization capacity of antivenoms on separated venom components was assessed and the coagulopathic venom peptides and enzymes that were either neutralized or remained active in the presence of antivenom were identified by correlating bioassay results with the MS data and with off-line generated proteomics data. The results showed that most snake venoms analyzed contained both procoagulants and anticoagulants. Most anticoagulants were identified as phospholipases A2s (PLA2s) and most procoagulants correlated with snake venom metalloproteinases (SVMPs) and serine proteases (SVSPs). This information can be used to better understand antivenom neutralization and can aid in the development of next-generation antivenom treatments.

Acute Severe Anaphylaxis in Nepali Patients with Neurotoxic Snakebite Envenoming Treated with the VINS Polyvalent Antivenom

Diagnosing and treating acute severe and recurrent antivenom-related anaphylaxis (ARA) is challenging and reported experience is limited. Herein, we describe our experience of severe ARA in patients with neurotoxic snakebite envenoming in Nepal. Patients were enrolled in a randomised, double-blind trial of high vs. low dose antivenom, given by intravenous (IV) push, followed by infusion. Training in ARA management emphasised stopping antivenom and giving intramuscular (IM) adrenaline, IV hydrocortisone, and IV chlorphenamine at the first sign/s of ARA. Later, IV adrenaline infusion (IVAI) was introduced for patients with antecedent ARA requiring additional antivenom infusions. Preantivenom subcutaneous adrenaline (SCAd) was introduced in the second study year (2012). Of 155 envenomed patients who received ≥ 1 antivenom dose, 13 (8.4%), three children (aged 5−11 years) and 10 adults (18−52 years), developed clinical features consistent with severe ARA, including six with overlapping signs of severe envenoming. Four and nine patients received low and high dose antivenom, respectively, and six had received SCAd. Principal signs of severe ARA were dyspnoea alone (n=5 patients), dyspnoea with wheezing (n=3), hypotension (n=3), shock (n=3), restlessness (n=3), respiratory/cardiorespiratory arrest (n=7), and early (n=1) and late laryngeal oedema (n=1); rash was associated with severe ARA in 10 patients. Four patients were given IVAI. Of the 8 (5.1%) deaths, three occurred in transit to hospital. Severe ARA was common and recurrent and had overlapping signs with severe neurotoxic envenoming. Optimising the management of ARA at different healthy system levels needs more research. This trial is registered with NCT01284855.

Haemotoxic snake venoms: their functional activity, impact on snakebite victims and pharmaceutical promise

Snake venoms are mixtures of numerous proteinacious components that exert diverse functional activities on a variety of physiological targets. Because the toxic constituents found in venom vary from species to species, snakebite victims can present with a variety of life-threatening pathologies related to the neurotoxic, cytotoxic and haemotoxic effects of venom. Of the 1·8 million people envenomed by snakes every year, up to 125 000 die, while hundreds of thousands survive only to suffer with life-changing long-term morbidity. Consequently, snakebite is one of the world's most severe neglected tropical diseases. Many snake venoms exhibit strong haemotoxic properties by interfering with blood pressure, clotting factors and platelets, and by directly causing haemorrhage. In this review we provide an overview of the functional activities of haemotoxic venom proteins, the pathologies they cause in snakebite victims and how their exquisite selectivity and potency make them amenable for use as therapeutic and diagnostic tools relevant for human medicine.

Orthogonal optimization of prokaryotic expression of a natural snake venom phospholipase A2 inhibitor from Sinonatrix annularis

Phospholipase A2 (PLA2) is a calcium-dependent enzyme that is involved in inflammatory processes such as the liberation of free arachidonic acid from the membrane pool for the biosynthesis of eicosanoids. Snake venom are known containing PLA2s (svPLA2s) which exhibit a wide variety of pharmacological effects including neurotoxicity, cardiotoxicity, myotoxicity and hemorrhage. Therefore, inhibition of svPLA2 would be advantageous to successful envenomation treatment. A gamma type PLI (PLA2 inhibitor) has been extracted from the serum of Sinonatrix annularis, a non-venomous snake indigenous to China. This showed strong inhibition of Deinagkistrrodon acutus PLA2, however, the PLIγ level in the serum and snake resource are not sufficiently sustainable for further research. To overcome these limitations, we constructed a His6-PLIγ pET28 fusion expression vector and transformed Escherichia coli BL21. To improve the expression of PLIγ, an orthogonal experiment [L16(4)(5)] was performed to optimize induction parameters. The optimized condition was determined to be: induction by 0.4 mM isopropyl-β-D-thiogalactoside (IPTG) for 6 h to the recombinant BL21 after its OD600 was 0.8, with continuous shaking cultivation at 190 rpm and 35 °C. Under these conditions, the amount of expressed protein could reach 57 mg/L. The His6-PLIγ was purified by nickel affinity chromatography and renatured by On-column refolding. The resulting PLIγ showed a good inhibitory effect of enzymatic activities to venom PLA2 isolated from D. acutus. Moreover, the PLIγ had a wide anti-hemorrhage activities to D. acutus, Naja atra and Agkistrodon halys venom.