Echis Research Articles

Melanism in the Saw-scaled Viper, Echis carinatus (Schneider, 1801) from Sheedvar Island, Persian Gulf, Iran

Melanism in Echis carinatus has been observed on Sheedvar Island in the Persian Gulf. A comparative analysis between melanistic and non-melanistic individuals showed no significant morphological or genetic differences. The evolution of melanism in E. carinatus may serve as camouflage or aid in predator avoidance, similar to other nocturnal viper species. However, a deeper understanding of the ecological role of melanism in nocturnal vertebrates, including E. carinatus, requires further investigation to clarify its broader significance.

Morphological characterization and sexual dimorphism of saw-scaled viper (<em>Echis</em>: viperidae: ophidia) population in Sri Lanka

The Saw-scaled vipers (SSV) of the genus Echis (Viperidae: Ophidia) primarily inhabit tropics. In Sri Lanka, E. carinatus is densely populated in the Northern Province where they account for over 50% of the local snakebites. Although it was initially reported as a unique Sri Lankan subspecies named E. c. sinhaleyus, its existence was later questioned, urging the need for more detail studies. The present study examined morphological characters and sexual dimorphism in 30 specimens (17 males and 13 females) collected from Kilinochchi and Jaffna Districts in the Northern Province, using 12 mensural and 17 meristic traits, updating Deraniyagala’s report of 1951. Results showed that the adult females have longer snout to vent length (SVL) than that of males (280.34±43.32 vs. 240.88±27.03), revealing a positive sexual dimorphism index. Males had a greater TL/SVL ratio (x̄̄=13.89±0.68) than that of females (x̄̄=10.65±085). ANCOVA test retrieved most accurate and an independent significant effect of ‘sex’ on TL while SVL serving as the covariate. Males and females shared consistent meristic characters, except for number of dorsal scales at the lower part of the body, ventral and sub-caudal scales. There were more ventral scales in females (145.54±3.31) than that of males (138.41±4.08), and sub-caudal scales were higher in number in males (28.94±1.85) than that of females (25.85±2.82). Although, there were some colour pattern variations of the specimens, (head pattern and ventral pattern), they were not sex-associated and distributed evenly between males and females. This is the first study to illustrate the detail morphometric characters; mensural traits; meristic traits, and color patterns and to demonstrate the sexual dimorphism in the SSV from Sri Lanka, with noticeable differences in the snoutvent length (SVL), tail length (TL), ventral scales, and sub-caudal scales between male and female.

Species-specific or para-specific antivenoms? On the immunological reactivity and neutralization efficacy for Saw-scaled viper venoms

Species-specific or para-specific antivenoms? On the immunological reactivity and neutralization efficacy for Saw-scaled viper venoms

Importance of the Cysteine-Rich Domain of Snake Venom Prothrombin Activators: Insights Gained from Synthetic Neutralizing Antibodies.

Snake venoms are cocktails of biologically active molecules that have evolved to immobilize prey, but can also induce a severe pathology in humans that are bitten. While animal-derived polyclonal antivenoms are the primary treatment for snakebites, they often have limitations in efficacy and can cause severe adverse side effects. Building on recent efforts to develop improved antivenoms, notably through monoclonal antibodies, requires a comprehensive understanding of venom toxins. Among these toxins, snake venom metalloproteinases (SVMPs) play a pivotal role, particularly in viper envenomation, causing tissue damage, hemorrhage and coagulation disruption. One of the current challenges in the development of neutralizing monoclonal antibodies against SVMPs is the large size of the protein and the lack of existing knowledge of neutralizing epitopes. Here, we screened a synthetic human antibody library to isolate monoclonal antibodies against an SVMP from saw-scaled viper (genus Echis) venom. Upon characterization, several antibodies were identified that effectively blocked SVMP-mediated prothrombin activation. Cryo-electron microscopy revealed the structural basis of antibody-mediated neutralization, pinpointing the non-catalytic cysteine-rich domain of SVMPs as a crucial target. These findings emphasize the importance of understanding the molecular mechanisms of SVMPs to counter their toxic effects, thus advancing the development of more effective antivenoms.

A Randomized Controlled Trial to Optimize Antivenom Therapy for Carpet Viper (Echis romani)-Envenomed Children in Nigeria.

In an open randomized controlled trial, we compared one vial (10 mL) to two vials (20 mL) of EchiTAb-plus-ICP (EPI) antivenom among children with systemic carpet viper (Echis romani) envenoming of moderate severity in northeastern Nigeria. Systemic envenoming, presenting with incoagulable blood, was diagnosed using the 20-minute whole blood clotting test (20WBCT). Eligible patients with positive 20WBCT whose guardians assented were recruited and randomly allocated to receive either one vial or two vials of EPI administered either as a bolus or as a slow continuous infusion. The primary outcome was permanent restoration of blood coagulability 6 hours after the start of treatment, assessed by the 20WBCT and repeated at 6, 12, 24, and 48 hours after treatment. Secondary outcomes were the incidences of early adverse reactions to antivenom treatment. Initial doses permanently restored blood coagulability at 6 hours in 34/39 (87.2%) of those treated with one vial and 39/41 (95.1%) of those treated with two vials of EPI (P = 0.258). However, the proportion with permanent restoration of clotting at 6 hours among patients randomized to bolus administration was 41 of 42 (97.6%) patients compared with 32 of 38 (84.2%) patients randomized to slow infusion of EPI antivenom (P = 0.049); however, the difference was not sustained through the remaining time points. There was no difference in early adverse reactions between those treated with the two different doses or modes of delivery. We conclude that the one-vial dose compared favorably to two vials of EPI antivenom with regards to effectiveness and safety among children with carpet viper envenoming of moderate severity in Nigeria.

Experimental production and efficacy testing of mono-specific antibodies against the venom of carpet viper (Echis ocellatus) from savannah Nigeria

Echis ocellatus is one of the commonest snakes responsible for envenomation in Nigeria. Antivenom is the only effective treatment, but the country suffers from a limited supply of effective antivenom. This study therefore aimed to explore the feasibility of effective, mono-specific antibodies production through immunization in rabbits using the venom of Echis ocellatus from Nigeria. The World Health Organization guide on antivenom production was employed in the immunization and the resultant antibodies were purified using protein A agarose column chromatography. Antibody titer reached a high plateau by 2-month immunization, and SDS PAGE of the sera suggests the presence of intact immunoglobulins accompanied with the heavy (50 kDa) and light (25 kDa) chains. The venom has an intravenous LD50 of 0.35 mg/kg in mice, and the venom lethality at a challenge dose of 2 LD50 was effectively neutralized by the antibodies with a potency value of 0.83 mg venom per g antibodies. The antibodies also neutralized the procoagulant activity of the venom with an effective dose (ED) of 13 ± 0.66 μl, supporting its use for hemotoxic envenomation. The study establishes the feasibility of developing effective, mono-specific antibodies against the Nigerian Carpet viper.

Clinico-Epidemiological Profile, Trends, and Health-Related Outcomes of Snakebite Victims: A One-Year Prospective Study from Eastern India.

Snakebite envenomation is a significant life-threatening public health problem in Southeast Asia (SEA). In this region, India reported the largest number of snakebite deaths from 2000 to 2019 (1.2 million), with an average of 58,000 deaths yearly. This prospective observational study was carried out among snakebite victims at the emergency department (ED) of a tertiary care public sector hospital in eastern India. A total of 145 cases of venomous snakebite were investigated. More than half (n = 81, 56%) of the snakebite victims were between 17 to 45 years. Most of the snakebite victims were male (68%) and were farmers (53%) by occupation. The majority of snakebites occurred during the daytime (76%) and while outdoors (67%). Most victims sustained a bite on the lower extremity (71%). The peak incidence of snakebites occurred from June to September (69%). Three-quarters of all patients were unaware of the required first aid measures following a snakebite. Among the 145 venomous snakebites, 48 were presumptively identified as the Indian cobra, 32 by the Indian krait, 56 by the Russel's viper, and 9 by saw-scaled viper. The mean duration from the snakebite to the onset of systemic effects in the Indian cobra was 52 ± 14.28 min, 66 ± 18.35 min in the Indian krait, 42 ± 13.47 min in Russel's viper, and 48 ± 16.38 min in saw-scaled viper. Respiratory failure was the commonly observed complication following an elapid envenomation. The mortality rate was 2.1% among the patients treated with antivenom. Snakebite is considered an occupational hazard in India, commonly affecting the young population in their productive period. The peak incidence was during monsoon season, and the majority had neurotoxic envenomation following an elapid bite (55%) that contributed to the increased mortality and morbidity among young adults. Of the 145 patients, the majority (84%) recovered fully with treatment; 16% of the victims developed morbidity viz cellulitis, respiratory failure, acute renal failure, compartment syndrome, local tissue necrosis, intracerebral hemorrhage, and disseminated intravascular coagulation. Appropriate first aid measures and timely medical intervention can significantly improve the treatment outcome following snakebites.

Exploring the Antivenom Potentials of Crinum Jagus Bulbs in the Treatment of Snake Bite from Girei, Adamawa State, Nigeria

Crinum jagus is a plant barely used in the treatment of snake bite in Nigeria and other African countries. This study focuses on evaluating the efficacy of the bulb of the plant against venom from Carpet viper snake. The plant samples were obtained, dried, blended while successive extraction was carried out using methanol. The crude methanolic extract and two distinct fractions obtained from column chromatography were used. Crystallized venom of Carpet viper was administered at varying concentrations. Forty mice were allocated into ten equal groups of four each. Mice in groups 4, 2 and 1 were given 150, 300 and 450 mg/kg of fraction 1 of Crinum jagus bulb respectively. Group 6, 5 and 7 were given same dose of fraction 2 obtained from Crinum jagus bulb. Group 7, 8 and 9 were given the crude methanolic extract at 150, 300 and 450 mg/kg, while group 10 served as the control. Apart from the Carpet viper venom that was administered intraperitonially, all others were administered orally. The Mice were observed over 24 hours before readings were taken. All the animals in the control group succumbed to envenomation within 7 to 15 minutes. In contrast, mice treated with both fractions and the crude methanolic extract exhibited significant survival rates, with survival rates increasing with higher dosages. Specifically, two mice from group 5 (F2 = 300 mg/kg), one from group 4 (F1 = 150 mg/kg), and one from group 3 (Cr = 300 mg/kg) survived the venom. The average weights of the mice across the groups varied, but no significant weight loss or adverse reactions were observed in the treated groups. These findings suggest that Crinum jagus bulb extracts possess potential antivenom properties against Carpet viper venom.

Systematic review and meta-analysis on the efficacy of Indian polyvalent antivenom against the Indian snakes of clinical significance.

Snakebite in India is a severe problem as it causes a mortality rate of 58,000 and a disability rate of 140,000 every year which is the highest among any other country. Antivenom is the primary therapy for snakebite, and its manufacturing techniques have essentially stayed unaltered for over a century. Indian polyvalent antivenom, a scientifically validated medicine for treating the toxic effects of snakebites, is available against the venom of the so-called Big Four snakes namely Spectacled cobra (Naja naja), Saw-scaled viper (Echis carinatus), Russell's viper (Daboia russelli) and the Common krait (Bungarus caeruleus), responsible for majority of the deaths in India. India hosts many other species of snakes, including cobras, kraits, saw-scaled vipers, sea snakes, and pit vipers, responsible for clinically severe envenomation. Neutralization strategy has been applied to access the efficacy of antivenoms, crucial for reducing snake bite deaths and disabilities. This review aims to conduct a systematic review and meta-analysis on the neutralization efficiency of the Polyvalent Antivenom (PAV) and focus on the factors that may contribute to the poor recognition of the antivenom towards the venom toxins. Reports focusing on the investigation of antivenom efficacy were searched and collected from several databases. Preclinical studies that reported the neutralization efficacy of the commercial antivenom against the medically important snakes of India were included. The articles were screened based on the inclusion criteria and 8 studies were shortlisted for meta-analysis. Pooled proportion was calculated for the antivenom efficacy reported by the studies and was found to be statistically significant with a 95% confidence interval. The heterogenicity in the venom toxicity and neutralization potency of the antivenom was evident in the overall estimate (proportion) and individual data. We provide comprehensive evidence on antivenom efficacy against medically important snakes from various parts of India which may aid in identifying the gaps in snake envenomation therapy and the need for novel potentially improved treatment of snakebites.

Immunoreactivity and neutralization efficacy of Pakistani Viper Antivenom (PVAV) against venoms of Saw-scaled Vipers (Echis carinatus subspp.) and Western Russell's Vipers (Daboia russelii) from the Indian subcontinent

Snakebite envenoming (SBE) is a priority Neglected Tropical Disease listed by the World Health Organization. South Asia is heavily affected, and virtually all countries in the region import polyvalent antivenom products from India for clinical use. The imported antivenoms, however, have suboptimal effectiveness due to geographical venom variation. Recently, a domestic bivalent product, named Pakistani Viper Antivenom (PVAV) has been developed specifically for Pakistani vipers, Echis carinatus sochureki and Daboia russelii. As a bivalent viperid antivenom, it is unknown yet if PVAV exhibits higher immunological binding and neutralization activities against viper venoms from distant locales compared with polyvalent antivenoms manufactured in India. This study thus examined the preclinical efficacy of PVAV against venoms of Western Russell's Vipers and Saw-scaled Viper subspecies from selected locales in the Indian subcontinent. PVAV generally outperformed the commonly used VINS polyvalent antivenom (VPAV, manufactured in India) in binding toward venoms, and showed superior or comparable neutralization efficacy against the venom procoagulant and hemorrhagic effects of Saw-scaled Vipers as well as Russell's Vipers from Pakistan and Sri Lanka. Based on normalized potency values, PVAV is far more potent than VPAV in neutralizing the lethality of all viper venoms, except that of the Indian Russell's Viper. The study shows conserved antigenicity of toxins responsible for major toxicity across these viperid venoms, and suggests the feasible production of a viper-specific antivenom with higher potency and broader geographical utility for the region.

Identifying key factors contributing to treatment costs for snakebite envenoming in private tertiary healthcare settings in Tamil Nadu, India.

India suffers ~58,000 annual deaths due to snakebites. The 'Big Four' snakes (Russell's viper, Indian cobra, common krait, and saw-scaled viper) that are responsible for most bites cause diverse clinical effects. Delayed treatment increases the risk of serious complications and treatment costs. Although government hospitals offer free treatment for snakebites in India, most patients opt for private healthcare, which is an out-of-pocket expense as they often lack health insurance coverage. This study aims to analyse snakebite treatment costs in private tertiary care hospitals in Tamil Nadu, India and identifies the key factors contributing to treatment costs. The treatment cost details for 913 snakebite victims were collected from 10 private tertiary care hospitals across Tamil Nadu. The data were classified into hospital, pharmacy, investigation, and laboratory costs, and analysed to determine various factors that contribute to the costs. The results demonstrate that the average treatment costs vary widely for different snakes. The hospital and pharmacy costs are higher than investigation and laboratory costs for all snakebites. Notably, Russell's viper bites cost significantly more than the bites from other snakes. Overall, the type of snake, nature of complications, specialist treatments required, and arrival time to hospitals were identified as some of the key factors for higher treatment costs. These data demonstrate that ~80% of snakebite patients can be treated with INR 100,000 (~GBP 1000 or USD 1200) or less. This study emphasises the urgent need to improve rural medical care by providing appropriate training for healthcare professionals and essential resources to facilitate early assessment of patients, administer the initial dose of antivenom and refer the patients to tertiary care only when needed. Moreover, the outcome of this study forms a basis for developing appropriate policies to regulate snakebite treatment costs and provide affordable medical insurance for vulnerable communities.

Evaluation of anti-snake venom activity of ethanolic leaf extract of Euphorbia hirta, Ageratum conyzoide and Anogeisus leiocarpus on West African Carpet Viper (Echis ocellatus) in envenomed Sprague Dawley rats.

Evaluation of anti-snake venom activity of ethanolic leaf extract of Euphorbia hirta, Ageratum conyzoide and Anogeisus leiocarpus on West African Carpet Viper (Echis ocellatus) in envenomed Sprague Dawley rats.

The Potential of Snake Venoms as Coagulation Agent for Hemorrhagic Trauma: A Review

Snake venom contains a variety of proteins and enzymes that can affect blood coagulation and have been investigated for their potential use as hemostatic agents to stop hemorrhage. Hemorrhage can be caused by a variety of factors, including injury, surgery, and certain medical conditions, and can be life-threatening if not controlled. Several components of snake venom have been identified as potential hemostatic agents. One such component is Batroxobin, a metalloproteinase found in the venom of the Bothrops atrox snake. Batroxobin has been shown to activate prothrombin to thrombin, which promotes clot formation and can be used to stop bleeding. Ancrod is a serine protease that can cleave fibrinogen, reducing the concentration of fibrinogen in the blood and preventing clot formation. Ancrod has been used as a hemostatic agent in the past, but its use has been limited due to concerns about its safety and efficacy. Other components of snake venom, such as those found in the venom of Russell's viper and the saw-scaled viper, have been found to have potential as hemostatic agents. These components have been shown to activate factor X and have been investigated as potential treatments for hemorrhage. The use of snake venom as a hemostatic agent is not without its challenges. One of the main concerns is the potential for adverse reactions, including allergic reactions, and the risk of complications such as thrombosis. Additionally, the availability of snake venom is limited, and the production of synthetic versions of these compounds can be challenging. Despite these challenges, the potential of snake venom as a hemostatic agent is promising, particularly in the development of new, more targeted treatments for hemorrhage. Further research is needed to fully understand the mechanisms of action of snake venom-derived hemostatic agents and to develop safe and effective therapeutic agents. In conclusion, snake venom contains a variety of components that have the potential as hemostatic agents to stop hemorrhage. While the use of snake venom-derived hemostatic agents is not without its challenges, these agents have promising potential in the treatment of a range of medical conditions. Keywords: Snake venom, coagulation agent, hemorrhagic trauma

A prospective observational phase IV study on effectiveness of animal derived polyclonal antibody antivenoms against West African carpet viper (Echis romani) induced coagulopathy and mortality

Conventional polyclonal antibody antivenoms are the mainstay of snakebite therapy. They have not been proven to be efficacious in randomized placebo controlled clinical trials among severely envenomed patients. There is also paucity of evidence on effectiveness especially in routine use. The current study evaluated their effectiveness in post marketing use among those managed with and without antivenom as regards to reversal of venom induced coagulopathy defined using the 20 min Whole Blood Clotting Test [20WBCT] and in averting death. The effectiveness of antivenom was evaluated among 5467 patients predominantly envenomed by the West African carpet viper (Echis romani) at 3 hospitals in Nigeria from 2021 to 2022. Two antivenoms Echitab G (EG) and Echitab ICP Plus (EP) were able to restore normal clotting within 6 h of administration in 58.0% [95% Confidence Interval (95%CI)] (51.2–64.5%) and 91.7% (90.4–93.0%) of patients respectively. They were able to restore normal clotting within 24 h of administration in 96.9% (94.0–98.7%) and 99.0% (98.4–99.4%) of patients respectively. The Odds Ratio [OR (95%CI)] of dying among patients with positive 20WBCT who were treated with ≥1 vial of either EG or EP compared to those not treated was 0.06 (0.02–0.23) and 0.07 (0.03–0.15) respectively. This equated to antivenom protection against in-hospital mortality of 93–94% among patients with confirmed coagulopathy though the benefit appeared abrogated among those without coagulopathy. The untreated natural mortality was 15.94% (95%CI:8.24–26.74%) without antivenom therapy while the overall mortality was 84/5105 (1.65%; 95%CI:1.32–2.03%. The Number Needed to Treat (NNT) to avert a death was 7 patients among those with coagulopathy. Antivenoms were safe with mild early adverse reactions observed among 2.6% (95%CI:2.13–3.08%) of antivenom recipients. Polyclonal antibody antivenoms are effective and safe for treating coagulopathic envenomed patients in Nigeria.

Fangs in the Ghats: Preclinical Insights into the Medical Importance of Pit Vipers from the Western Ghats.

The socioeconomic impact of snakebites in India is largely attributed to a subset of snake species commonly known as the 'big four'. However, envenoming by a range of other clinically important yet neglected snakes, a.k.a. the 'neglected many', also adds to this burden. The current approach of treating bites from these snakes with the 'big four' polyvalent antivenom is ineffective. While the medical significance of various species of cobras, saw-scaled vipers, and kraits is well-established, the clinical impact of pit vipers from regions such as the Western Ghats, northeastern India, and the Andaman and Nicobar Islands remains poorly understood. Amongst the many species of snakes found in the Western Ghats, the hump-nosed (Hypnale hypnale), Malabar (Craspedocephalus malabaricus), and bamboo (Craspedocephalus gramineus) pit vipers can potentially inflict severe envenoming. To evaluate the severity of toxicity inflicted by these snakes, we characterised their venom composition, biochemical and pharmacological activities, and toxicity- and morbidity-inducing potentials, including their ability to damage kidneys. Our findings highlight the therapeutic inadequacies of the Indian and Sri Lankan polyvalent antivenoms in neutralising the local and systemic toxicity resulting from pit viper envenomings.

Type I-like metalloproteinase in the venom of the West African saw-scaled carpet viper (Echis ocellatus) has anti-trypanosomal activity against African trypanosomes

African trypanosomiasis is an infectious disease caused by hemoparasites of the genus Trypanosoma and remains a major health problem in Africa - killing around 4000 people and animals worth an estimated $5 billion, annually. The absence of a vaccine and satisfactory drug against African trypanosomiasis (AT) necessitates the continued search for new chemotherapy options. Owing to the rich biochemical diversity in snake venom, it has recently become a source of therapeutic peptides that are being explored for the development of novel drug candidates for diverse ailments such as cancers and infectious diseases. To explore this, Echis ocellatus venom (EOV) was investigated for the presence of an anti-Trypanosoma factor, with the subsequent aim to isolate and identify it. Crude EOV was collected and tested in vitro on the bloodstream form (BSF) i.e. long and slender morphological form of Trypanosoma brucei and T. congolense. This initial testing was followed by a sequential anti-trypanosomal assay guided purification of EOV using ethanol precipitation, distillation, and ion exchange (IEX) chromatography to obtain the active trypanocidal component. The purified anti-Trypanosoma factor, estimated to be a 52-kDa protein on SDS-PAGE, was subjected to in-gel trypsin digestion and 2D RP HPLC-MS/MS to identify the protein. The anti-Trypanosoma factor was revealed to be a zinc-dependent metalloproteinase that contains the HEXXHXXGXXH adamalysin motif. This protein may provide a conceptual framework for the possible design of a safe and effective anti-trypanosomal peptide for the treatment of AT.

Proteomic Analysis, Immuno-Specificity and Neutralization Efficacy of Pakistani Viper Antivenom (PVAV), a Bivalent Anti-Viperid Antivenom Produced in Pakistan.

Snakebite envenoming is a neglected tropical disease prevalent in South Asia. In Pakistan, antivenoms are commonly imported from India despite the controversy over their effectiveness. To solve the problem, the locals have developed the Pakistani Viper Antivenom (PVAV), raised against Sochurek's Saw-scaled Viper (Echis carinatus sochureki) and Russell's Viper (Daboia russelii) of Pakistani origin. This study is set to evaluate the composition purity, immuno-specificity and neutralization efficacy of PVAV. Chromatographic and electrophoretic profiling coupled with proteomic mass spectrometry analysis showed PVAV containing high-purity immunoglobulin G with minimum impurities, notably the absence of serum albumin. PVAV is highly immuno-specific toward the venoms of the two vipers and Echis carinatus multisquamatus, which are indigenous to Pakistan. Its immunoreactivity, however, reduces toward the venoms of other Echis carinatus subspecies and D. russelii from South India as well as Sri Lanka. Meanwhile, its non-specific binding activities for the venoms of Hump-nosed Pit Vipers, Indian Cobras and kraits were extremely low. In the neutralization study, PVAV effectively mitigated the hemotoxic and lethal effects of the Pakistani viper venoms, tested in vitro and in vivo. Together, the findings suggest the potential utility of PVAV as a new domestic antivenom for the treatment of viperid envenoming in Pakistan.

Saw scaled viper bite and envenomation in the subcutaneous plane.

Dear Editor, We present a 25-year-old man bitten by a saw scale viper on his left hand. The patient presented to a medical emergency 4 hours after the bite. On examination, there was swelling, edema, and cellulitis in the left hand up to the axilla [Figure 1]. On laboratory evaluation, his Hb was 120 g/L, with a normal white cell count (9.0 × 109/L) and platelet 152 × 109/L, with coagulation showing normal reading (PT 12 s, INR, 0.98, APPT 29 s) and serum creatinine (88.42 umol/L). His 20-min whole blood clotting test was normal. Viper venom contains serine proteases, metalloproteinases, C-type lectins, and phospholipases and shows both procoagulant and anticoagulant effects on the blood clotting mechanism resulting in defibrination syndrome.[1] Among the toxins of saw-scaled viper, phospholipase helps in the subcutaneous spread of venom by dissolving the cell membrane. In the present case, envenomation was in the subcutaneous plane causing swelling, edema, and cellulitis. There was no systemic manifestation of envenomation. In such a scenario question arises whether to give antisnake venom or not when there is no defibrination syndrome or systemic manifestation of envenomation. In our patient, there was no coagulopathy at the time of admission and 24 hours after envenomation. But given local envenomation, it is decided to give antisnake venom. We gave 150 mL of antisnake venom over 8 hours. After that swelling started subsiding and over the next 24 hours, there was a significant decrease in swelling, cellulitis, and edema [Figure 2]. Giving antisnake venom in a locally toxic situation is beneficial and works by creating a concentration gradient across the extracellular compartment and sucking out intracellular venom and subsequent decrease in swelling, cellulitis, and edema.[2] Whenever there is local envenomation at the site of the bite by viper without systemic manifestation antisnake venom should be given.Figure 1: Envenomation in the left hand with swelling, edema, and cellulitisFigure 2: Swelling, edema, and cellulitis subsided after antisnake venomConsent Taken from the patient. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Performance of the 20 minutes Whole Blood Clotting Test in detection, monitoring and antivenom therapy of West African Carpet viper (Echis romani) envenoming in resource constrained settings in Nigeria

The 20 minutes Whole Blood Clotting Test (20WBCT) was evaluated in 1541 snakebite patients at 3 hospitals in Nigeria. It was useful in detection, monitoring, guiding antivenom therapy and prognostication of coagulopathy, with initial sensitivity of 84.7% (95%CI:82.7–86.5%) and specificity of 64.3% (95%CI:50.4–76.7%) compared to clinical envenoming. It led to correct decisions regarding administration or withholding antivenom in 97.93% of patients. The proportion of carpet viper (Echis romani) envenomed patients who restored clotting rose steadily following effective antivenom therapy. Patients with positive 20WBCT had severer envenoming, required more blood transfusion, had longer hospital stay and derived higher antivenom protection against death from carpet viper. However, there was no association between positive 20WBCT and fatality or complications.

Venom-induced consumptive coagulopathy leading to thrombotic microangiopathy following Echis carinatus sochureki bite: is snake antivenom effective?

The incidence of thrombotic microangiopathy (TMA) following snake bite is reported to be ranging from 3.6 to 15%. We report a 10-year-old boy who developed TMA and due to venom-induced consumptive coagulopathy (VICC) despite receiving adequate and timely doses of snake antivenom following a bite of saw-scaled viper (Echis carinatus sochureki). VICC was managed by plasmapheresis. Though snake bite envenomation-associated renal complications are not uncommon, possibility of TMA should be considered early during management. Our patient developed TMA with subsequent acute cortical necrosis after saw-scaled viper bite despite an adequate and timely dose of snake antivenom which emphasizes the ineffectiveness of antivenom against the venom of given snake species leading to long-term complications.