Antivenom Administration Research Articles

Factors Associated with Complications of Snakebite Envenomation in Health Facilities in the Cascades Region of Burkina Faso from 2016 to 2021

Snakebite envenomation remains a major cause of morbidity and mortality in rural populations. This study identified factors associated with the complications of snakebite envenomation reported in the Cascades region of Burkina Faso. This cross-sectional study used the routine data of patients admitted for snakebite envenomation at five health facilities between 1 January 2016 and 31 December 2021. Data were collected on sociodemographic, clinical, and therapeutic characteristics of patients with signs of envenomation. Bivariate and multivariate analyses were conducted to identify factors associated with complications. Among the 846 patients with envenomation, 355 (42%) experienced complications. Local complications (23.2%, 196/846) included wounds and skin necrosis, whereas systemic complications (34.3%, 290/846) included hemorrhage, shock, and coma. Of all complicated cases, 7.6% (27/355) died. Factors associated with complications were rural residence (AOR: 4.80; 95% CI: 2.21–11.4), incision at the bite site (AOR: 4.31; 95% CI: 2.51–7.52), tourniquet application (AOR: 5.52; 95% CI: 1.42–30.8), bleeding (AOR: 14.2; 95% CI: 8.80–23.4), abnormal vital signs (AOR: 14.3; 95% CI: 9.22–22.7), and lack of antivenom administration (AOR: 2.92; 95% CI: 1.8–4.8). These findings highlight the importance of antivenom availability and public awareness for reducing the incidence of complications of snakebite envenomation.

Hemorrhagic erucism due to Lonomia spp. in Peru – A call for action

Envenomation due to exposure to caterpillars is an emerging public health problem. A life-threatening bleeding diathesis has been described in South America after exposure to Lonomia obliqua or L. acheolus. Deforestation, forest degradation, and global warming might increase the frequency of human exposure to these insects. Prompt recognition and administration of antivenom are crucial to ensure a favorable outcome.

Acute adverse effects of F(ab’)₂AV and FabAV use for rattlesnake Envenomations: A four-year poison center study

Rattlesnake envenomations account for many of the Crotalid envenomations in the United States annually. Two antivenoms are currently available to treat Crotalid envenomation in this country: Crotalidae-polyvalent ovine immune Fab antivenom (CroFab®; FabAV) and Crotalidae equine immune F(ab’)₂ antivenom (ANAVIP®; F(ab’)₂AV). Few studies have compared the adverse effect rates for each.We performed a retrospective chart review of rattlesnake envenomations called to the California Poison Control System from October 2018 to August 2022. Those treated at healthcare facilities with either antivenom were included. Those treated with both antivenoms were excluded.Records were obtained from the poison center electronic medical records system. Demographic and clinical data were abstracted. “Severe” adverse events were defined as multi-organ system involvement, swelling of the patient's airway, and/or hemodynamic instability. All others were categorized as “non-severe.”A total of 481 cases were included with 360 treated with FabAV and 121 with F(ab’)₂AV. The median age was 47 and 46 years, and 72 % and 73 % were male, respectively. Clinical signs and symptoms of envenomation were similar in each group.The FabAV group received a median of six vials. The F(ab’)₂AV group received a median of 10 vials, based on the recommended loading doses of FabAV and F(ab’)2AV. Following antivenom administration, 18 individual acute non-severe AEs were reported in 12 FabAV-treated patients. Two acute non-severe AEs were reported in two F(ab’)₂AV-treated patients. Rash or urticaria was the most commonly reported adverse effect in both groups after antivenom administration. Five patients (1.5 %) had severe adverse events reported in the poison center records following FabAV administration, and none were reported following F(ab’)₂AV administration (p = 0.025).Overall, our poison center data suggests the rate of adverse events is low following the use of either antivenom. Our findings are limited by the lack of consistent timing data, a smaller F(ab’)₂AV cohort, retrospective format, and use of poison center data.

Handheld point-of-care devices for snakebite coagulopathy: a scoping review.

Venom induced consumption coagulopathy (VICC) is a common complication of snakebite that is associated with hypofibrinogenaemia, bleeding, disability, and death. In remote tropical settings, where most snakebites occur, the 20-minute whole blood clotting test is used to diagnose VICC. Point-of-care (POC) coagulation devices could provide an accessible means of detecting VICC that is better standardised, quantifiable, and more accurate. In this scoping review, the mechanistic reasons that previously studied POC devices have failed in VICC are considered, and evidence-based recommendations are made to prioritise certain devices for clinical validation studies. Four small studies have evaluated a POC international normalised ratio (INR) device in patients with Australian Elapid, Daboia russelii and Echis carinatus envenoming. All of these studies used POC INR devices that rely on a thrombin substrate endpoint, which, unlike laboratory-based INR measurement, is known to underestimate INR in patients with hypofibrinogenaemia. Seventeen commercially available POC devices for measuring INR, activated clotting time (ACT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, and fibrin(ogen) degradation products (FDP) have been reviewed. POC INR devices that detect fibrin clot formation, as well as a novel POC device that quantifies fibrinogen were identified, that show promise for use in patients with VICC. These devices could support more accurate allocation of antivenom, reduce the time to antivenom administration, and provide improved clinical trial outcome measurement instruments. There is an urgent need for these promising POC coagulation devices to be validated in prospective clinical snakebite studies.

Experıences Of Emergency Physıcıans On Scorpıon Stıngs

INTRODUCTION and PURPOSE: This study aims to evaluate the level of knowledge and approaches of emergency physicians about scorpion stings. MATERIALS and METHODS: In the study, aquestionnaire including 16 questions was administered to emergency physicians about their titles, length of service in the emergency department, geographical region and institutional information, experiences with scorpion stings, treatment approaches, and hospitalization information of the patients. RESULTS: A total of 282 physicians participated in the study. In emergency medicine physicians (EMPs), regularly checking the availability of scorpion antivenom (p=0.01), taking precautions for complications before antivenom administration (p=0.03), and preferring intravenous (IV) route for scorpion antivenom administration were found to be significantly higher compared to other title groups. Needing consultation before scorpion antivenom (p=0.01) and recommending antibiotic prophylaxis to sting patients (p=0.02) were significantly lower in EMPs compared to other title groups. 31.7% (n=26) of general practitioners administered antivenom "half to the wound edge/half intramuscularly", which is significantly higher compared to other groups (p=0.01). Hospitalization problems in sting cases were most frequently experienced in university hospitals (p= 0.01). DISCUSSION and CONCLUSION: Our study indicated errors in managing scorpion sting patients and antivenom use. The necessity of reorganization of vocational and undergraduate training should be evaluated.

Infections following rattlesnake envenomation and use of antibiotics.

There are 7000-8000 venomous snake bites annually in the USA. Antibiotics are commonly administered to bite victims because infection is difficult to differentiate from local tissue injury following envenomation. The Arizona Poison and Drug Information Center (APDIC) in Tucson oversees antivenom administration for 14 Arizona counties. Records (1999-2021) were searched for antibiotic use and confirmed infections after a rattlesnake bite. There were 4160 calls to APDIC regarding rattlesnakes. After excluding bites to animals, 'dry bites', prisoners and records with missing data, 2059 records were evaluated. Systemic antibiotics were administered to 206 patients (10% of bite victims). Twenty patients (0.97%) had confirmed infections, including cellulitis (n=10), fasciitis (n=4), abscess (n=3) and osteomyelitis (n=3). Five of the victims had positive blood cultures. The presence of tissue necrosis, leukocytosis, fever and elevated fibrinogen levels did not discriminate between toxic effects of venom and infection. Confirmed infections following a rattlesnake bite are uncommon (0.97% of bites). Physicians should refrain from prescribing antibiotics, as they are not justified for most rattlesnake bite victims and the variety of pathogens encountered precludes use of any single effective antibiotic.

Comparing the Use of Crotaline-Polyvalent Immune Fab (Ovine) Versus Observation in Children.

In the United States, studies are inconclusive regarding the indications for polyvalent antivenom administration for crotaline envenomation. We compared polyvalent antivenom administration versus observation used at 2 separate institutions. We hypothesized that deferring antivenom leads to increased hospital length of stay and surgical interventions. Retrospective chart review of children who presented to Le Bonheur Children's Hospital (LBCH) in Memphis, Tennessee, and Monroe Carell Jr Children's Hospital at Vanderbilt (MCJCHV) in Nashville, Tennessee, from 2009 to 2021. Patient demographics, treatment utilization, bite location, and outcomes from both sites were statistically examined. A total of 183 patients met the inclusion criteria (123 at LBCH, 60 at MCJCHV). At LBCH, mean age was 9.2 years, 54% were male, and 79% of known snakes identified as copperheads. At MCJCHV, mean age was 8.9 years, 65% were male, and 88% of known snakes identified as copperheads. The most commonly envenomated areas for both sites were the foot (42%), hand (27%), and ankle (26%). Patients at LBCH were managed with antivenom only 25% of the time, whereas 75% were observed; 82% of MCJCHV patients were managed with antivenom (P < 0.001). There were no significant differences in length of stay (mean, 1.5 days at LBCH and 1.8 days at MCJCHV; P = 0.136) or surgical intervention (3.3% of LBCH encounters, 5.0% of MCJCHV encounters; P = 0.685). Secondary outcomes aside from coagulopathy and admission location (intensive care unit vs floor) were also not significant. The use of antivenom did not impact hospital length of stay or surgical interventions. Our results should be interpreted cautiously as our study reflects regional experiences with snake species in the Southeast United States and not North America as a whole. Other institutional differences in management and smaller n at MCJCHV may have contributed to different outcomes. Further study is needed to determine intermediate and long-term effects of deferring antivenom use.

Taking the sting out of scorpions: Electrophysiological investigation of the relative efficacy of three antivenoms against medically significant Centruroides species

In this study, we report the innovative application of whole-cell patch-clamp electrophysiology in assessing broad-spectrum neutralisation by three different antivenoms, of venoms from the medically significant scorpion genus Centruroides. Envenomations by as many as 21 species from the Centruroides genus result in up to 300,000 envenomations per year in Mexico, which poses significant and potentially life-threatening pathophysiology. We first evaluated the in vitro manifestation of envenomation against two human voltage-gated sodium (hNaV) channel subtypes: hNaV1.4 and hNaV1.5, which are primarily expressed in skeletal muscles and cardiomyocytes, respectively. The neutralisation of venom activity was then characterised for three different antivenoms using a direct competition model against the more potent target, hNaV1.4. While broad-spectrum neutralisation was identified, variation in neutralisation arose for Centruroides elegans, C. limpidus, C. noxius and C. suffusus venoms, despite the presence of a number of these venoms within the immunising mixture. This raises questions regarding the truly “broad” neutralisation capacity of the antivenoms. This study not only extends previous validation of the in vitro investigation of antivenom efficacy utilising the whole-cell patch-clamp technique but also underscores the potential of this animal-free model in exploring cross-reactivity, experimental scalability, and most importantly, informing clinical management practices regarding the administration of antivenom in Mexico.

Immunoreactivity of eastern small eyed snake (Cryptophis nigrescens) venom towards species-specific antibodies of five medically important venomous Australian elapids.

The eastern small eyed snake (Cryptophis nigrescens; CN) is an uncommon cause of snakebite in Australia despite the widespread distribution of the snake along the east coast of Australia. Diagnosis of envenomation relies on identification of the snake which is often not possible with animal snakebite cases. This study examined the immunoreactivity profile of CN venom towards specific rabbit IgG made against the medically relevant snake venom immunotypes found in Australia (tiger, brown, black, death adder and taipan). A simultaneous sandwich ELISA format was used to quantify CN venom binding to venom specific Protein A purified rabbit IgG. The binding profiles demonstrated weak binding of CN venom to rabbit IgG made against both tiger (N. scutatus) and black snake (P. australis) venoms with approximately 0.19% and 0.069% cross reactivity, respectively. However, the concentration of venom likely to be present in the urine of CN envenomed patients and the low cross reactivity suggest that envenomed veterinary patients are unlikely to be detected in the commercial snake venom detection kit. It is possible that CN envenomation is more common but may be underdiagnosed where snake venom antigen detection is relied upon solely. Serum biochemical abnormalities also overlap with other snake species found in the same geographical area. In respect of antivenom therapy, administration of tiger snake antivenom is supported by the binding data, but due to the low cross reactivity multiple vials may be required. Limited clinical evidence also supports the efficacy of tiger snake antivenom for envenomation by CN.

Histopathological changes of mice tissues in course of the envenomation by the Macrovipera lebetina obtusa venom and the neutralizing effect of the ovine-derived experimental antivenom

Viper bites pose a significant public health issue in Armenia, even within urban areas, often resulting in clotting disorders, hypofibrinogenemia, and tissue necrosis in humans. This study investigates histopathological changes in various tissues during mice envenomation by West-Asian blunt-nosed viper (Macrovipera lebetina obtusa) venom, as well as the recovery process aided by experimental antivenom derived from sheep. The high venom dose caused substantial damage to the heart, lungs, liver, and kidneys in mice, indicating systemic harm. While antivenom administration can prevent mortality in mice envenomation, it may not fully mitigate histological damage in affected organs. Additionally, the study highlights the importance of timing antivenom administration, as the severity of tissue alterations can vary depending on the duration of envenomation. These findings shed light on antivenom's effects on viper envenomation and stress the need for further research to optimize its timing and dosage for minimizing histological damage and enhancing clinical outcomes.

Neutralizing Effect of Solanum dasyphyllum Schumach. &amp;Thonn Extract against Naja nigricollis Venom-induced Toxicity

Background: Clinical treatments for snakebite envenomation typically involve the administration of antivenom, which can lead to various side effects. However, due to the limitations of conventional antivenoms in effectively treating snakebite envenomation, scientists are now exploring alternative sources for potential antivenom compounds, particularly those derived from plants. Solanum dasyphyllum belongs to the Solanaceae family. This plant has been found to possess several beneficial properties, including neuromuscular, anti-poisoning, and antispasmodic effects. Aim of the Study: This study aimed to investigate the phytochemical constituents and the In-vivo detoxifying effect of S. dasyphyllum extract against N. nigricollis-induced toxicity. Materials and Methods: Phytochemical screening and anticoagulant assays were conducted using standard procedures. The neutralizing and detoxifying effects of S. dasyphyllum were investigated in-vivo using locally bred adult Swiss mice. The neutralizing effect was evaluated in mice by administering a mixture of N. nigricollis venom and methanol leaf extract of S. dasyphyllum (100-400 mg/kg). The detoxifying effect was investigated by administering S. dasyphyllum via the intramuscular route 10 minutes after inoculation with N. nigricollis venom through the intraperitoneal route. Results: The results of phytochemical screening revealed the presence of tannins, cardiac glycosides, saponins, flavonoids, and alkaloids, and the absence of anthraquinone and starch. The results of the clotting time of human blood treated with N. nigricollis venom showed a significant reduction in the clotting time with an increase in the concentration of methanol leaf extract of S. dasyphyllum. Additionally, the mortality of the mice that were pre-treated with N. nigricollis venom before injected with various doses of plant extract and those that were co-administered with the venom and plant extract significantly lower compared to mice administered with the venom alone. S. dasyphyllum significantly reduced the extent of lipid peroxidation and the activity of the enzyme acetylcholinesterase compared to the untreated group. Conclusions: S. dasyphyllum possesses antivenom activity against N. nigricollis, and this result further supports the ethnomedical use of the plant in the treatment of snakebite envenomation.

A randomized controlled trial and prospective cohort investigating antivenom for red-bellied black snake envenomation

Introduction Antivenom is first line treatment for snake envenomation worldwide, despite few placebo controlled clinical trials demonstrating effectiveness. We aimed to investigate whether early antivenom in red-bellied black snake (Pseudechis porphyriacus) bites would prevent systemic myotoxicity. Methods We undertook a multicentre randomized placebo-controlled trial of antivenom for red-bellied black snake bites with patients recruited from the Australian Snakebite Project (July 2014 to June 2020). In addition, we report all patients with red-bellied black snake bites during the same period, comparing the same outcomes. Patients over 2 years of age with definite red-bellied black snake bites and early systemic effects were randomized to receive 50 per cent glucose (placebo) or tiger snake antivenom within 6 hours post-bite, or in the cohort group received antivenom determined by the treating clinician. The primary outcome was the proportion of patients with myotoxicity (peak creatine kinase activity >1,000 U/L). Secondary outcomes were: area under the curve of total creatine kinase elevation over 48 hours, presence of venom post-antivenom, and adverse reactions. We analyzed both the randomized control trial patients and the combination of randomized control trial and cohort patients. Results Fifteen patients were recruited to the randomized controlled trial, and a cohort of 68 patients who were not randomized were included in the analysis. After treatment, two of seven patients given placebo had a peak creatine kinase activity >1,000 U/L versus none of the eight given antivenom (difference in favour of antivenom; 29 per cent; 95 per cent confidence interval:-18 per cent to +70 per cent; P = 0.2). The median area under the curve of total creatine kinase elevation over 48 hours in patients given placebo was 0 U/L*h (interquartile range: 0–124 U/L*h), which was not significantly different to those given antivenom: 197 U/L*h (interquartile range: 0–66,353 U/L*h; P = 0.26). Venom was not detected post-antivenom in six patients with measured venom concentrations given antivenom. Two patients given antivenom had immediate hypersensitivity reactions, one severe anaphylaxis, and another had serum sickness. Combining randomized and not randomized patients, three of 36 (8 per cent) administered antivenom less than 6 hours post-bite had a peak creatine kinase activity >1,000 U/L versus 17/47 (36 per cent) patients not receiving antivenom less than 6 hours post-bite (difference in favour of antivenom 29 per cent; 95 per cent confidence interval: 8 per cent to 44 per cent; P < 0.004). Overall, 13/36 (36 per cent) patients administered antivenom within 6 hours had hypersensitivity reactions, six severe anaphylaxis (17 per cent). Discussion We found that early antivenom was effective in red-bellied black snake bites, and only three patients need to be given antivenom within 6 hours to prevent myotoxicity in one (number needed to treat = 3). However, one in three patients administered antivenom developed a hypersensitivity reaction, and one in six had severe anaphylaxis. The major limitation of this study was the small number of patients recruited to the randomized controlled trial. Conclusion Administration of antivenom in red-bellied black snake envenomation within 6 hours post-bite appeared to decrease the proportion of patients with myotoxicity, but a third of patients had adverse reactions.

A Guide to the Clinical Management of Vipera Snakebite in Italy.

The genus Vipera encompasses most species of medically significant venomous snakes of Europe, with Italy harbouring four of them. Envenomation by European vipers can result in severe consequences, but underreporting and the absence of standardised clinical protocols hinder effective snakebite management. This study provides an updated, detailed set of guidelines for the management and treatment of Vipera snakebite tailored for Italian clinicians. It includes taxonomic keys for snake identification, insights into viper venom composition, and recommendations for clinical management. Emphasis is placed on quick and reliable identification of medically relevant snake species, along with appropriate first aid measures. Criteria for antivenom administration are outlined, as well as indications on managing potential side effects. While the protocol is specific to Italy, its methodology can potentially be adapted for other European countries, depending on local resources. The promotion of comprehensive data collection and collaboration among Poison Control Centres is advocated to optimise envenomation management protocols and improve the reporting of epidemiological data concerning snakebite at the country level.

Retrospective Evaluation of Clinical and Clinicopathologic Findings, Case Management, and Outcome for Dogs and Cats Exposed to Micrurus fulvius (Eastern Coral Snake): 92 Cases (2021-2022).

This retrospective, observational study describes the clinical findings, case management trends, and outcomes of 83 dogs and nine cats exposed to eastern coral snakes in a university teaching hospital setting. The medical records of dogs and cats that received antivenom following coral snake exposure were reviewed. Data collected included signalment, time to antivenom administration, physical and laboratory characteristics at presentation, clinical course during hospitalization, length of hospitalization, and survival to discharge. The mean time from presentation to coral snake antivenom administration was 2.26 ± 1.46 h. Excluding cases where the owner declined in-hospital care, the mean hospitalization time for dogs and cats was 50.8 h and 34 h, respectively. The mean number of antivenom vials was 1.29 (1-4). Gastrointestinal signs (vomiting and ptyalism) occurred in 42.2% (35/83) of dogs and 33.3% (3/9) of cats. Peripheral neurologic system deficits (ataxia, paresis to plegia, absent reflexes, and hypoventilation) were noted in 19.6% (18/92) of dogs and cats. Hemolysis was also common in 37.9% (25/66) of dogs but was not observed in cats. Mechanical ventilation (MV) was indicated in 12% (10/83) of dogs but no cats. Acute kidney injury (AKI), while rare, was a common cause of euthanasia at 20% (2/5) and was the most common complication during MV at 44.4% (4/9). Pigmenturia/hemolysis occurred in 88.9% (8/9) of MV cases and in all cases with AKI. Despite delays in antivenom administration by several hours, dogs and cats with coral snake exposure have low mortality rates (6% of dogs (5/83) and 0% of cats). Gastrointestinal signs were common but were not predictive of progression to neurological signs. Thus, differentiating between coral snake exposure and envenomation before the onset of neurological signs remains challenging.

Investigating skeletal muscle biomarkers for the early detection of Australian myotoxic snake envenoming: an animal model pilot study

Introduction Myotoxicity is an important toxidrome that can occur with envenoming from multiple Australian snake types. Early antivenom administration is an important strategy to reduce the incidence and severity of myotoxicity. The current gold standard biomarker, serum creatine kinase activity, does not rise early enough to facilitate early antivenom administration. Several other skeletal muscle biomarkers have shown promise in other animal models and scenarios. The aim of this study was to examine the predictive values of six skeletal muscle biomarkers in a rat model of Australian snake myotoxicity. Methods Sprague-Dawley rats were anaesthetised and administered either Pseudechis porphyriacus (red-bellied black snake) or Notechis scutatus (tiger snake) venom, or normal saline via intramuscular injection. Blood samples were collected. Assays were performed for serum creatine kinase skeletal muscle troponin-I concentration, skeletal muscle troponin-C concentration, myoglobin activity, skeletal muscle myosin light chain-1 concentration, and creatine kinase-MM activity. Serum markers were plotted against time, with comparison of area under the concentration (or activity)-time curve. The predictive values of six skeletal muscle biomarkers were examined using receiver operating characteristic curves. Results There was no difference in area under the serum creatine kinase activity-time curve between venom and control groups. Serum creatine kinase-MM activity rose early in the venom treated rats, which had a significantly greater area under the serum activity-time curve. No difference in area under the serum concentration-time curve was demonstrated for the other biomarkers. Creatine kinase-MM activity had a superior predictive values than creatine kinase activity at 0–4 hours and 0–10 hours after venom administration, as indicated by area under the receiver operating characteristic curves (95 per cent confidence intervals) of 0.91 (0.78–1.00) and 0.88 (0.73–1.00) versus 0.79 (0.63–0.95) and 0.66 (0.51–0.80). Discussion The limitations of serum creatine kinase activity in early detection of myotoxicity were demonstrated in this rat model. Conclusion Serum creatine kinase-MM activity was superior for early detection of Australian myotoxic snake envenoming.

Urgent administration of antivenom following proven krait bites in Southeast Asia irrespective of neurotoxic symptoms.

Urgent administration of antivenom following proven krait bites in Southeast Asia irrespective of neurotoxic symptoms.

Bothrops lanceolatus Envenoming in Martinique: A Historical Perspective of the Clinical Effectiveness of Bothrofav Antivenom Treatment.

Bothrofav, a monospecific antivenom, was introduced in June 1991 and has shown excellent effectiveness against life-threatening and thrombotic complications of Bothrops lanceolatus envenoming. Because of the reoccurrence of cerebral stroke events despite the timely administration of antivenom, new batches of Bothrofav were produced and introduced into clinical use in January 2011. This study's aim was to evaluate the effectiveness of Bothrofav generations at treating B. lanceolatus envenoming. During the first period of the study (2000-2010), 107 patients were treated with vials of antivenom produced in June 1991, while 282 envenomed patients were treated with vials of antivenom produced in January 2011 in the second study period (2011-2023). Despite timely antivenom administration, thrombotic complications reoccurred after an interval free of thrombotic events, and a timeframe analysis suggested that the clinical efficacy of Bothrofav declined after it reached its 10-year shelf-life. In of the case of an antivenom shortage due to the absence of regular batch production, no adverse effects were identified before the antivenom reached its 10-year shelf-life, which is beyond the accepted shelf-life for a liquid-formulation antivenom. While our study does not support the use of expired antivenom for potent, life-threatening B. lanceolatus envenoming, it can be a scientific message to public entities proving the necessity of new antivenom production for B. lanceolatus envenoming.

Ruthenium-based antivenom attenuates Crotalus atrox venom mediated coagulopathy in rabbits.

The Western diamondback rattlesnake ( Crotalus atrox ) is a medically important venomous snake in the Southwestern United States, injuring humans, and their companion animals. The goals of this investigation were to utilize a rabbit model of subcutaneous envenomation to assess Crotalus atrox venom coagulopathy and determine the efficacy of a ruthenium-containing antivenom (RA) in attenuating it. Sedated New Zealand White rabbits had viscoelastic measurements of whole blood coagulation kinetics obtained from ear artery samples. Crotalus atrox venom (4 mg/kg) was injected subcutaneously and changes in coagulation determined over three hours and compared to samples obtained prior to envenomation. Other rabbits had site-directed RA injected 5 min after venom injection. A significant decrease in the velocity of clot growth and thrombus strength was observed in animals injected with venom alone. Site-directed administration of RA resulted in no change in coagulation over the 3 h following venom injection. The interaction of antivenom administration and time was significantly different in the cases of clot growth velocity and strength. A novel rabbit model was used to define the toxicodynamic profile of coagulopathy of Crotalus atrox venom and demonstrate the efficacy of RA. Future investigation is planned involving other medically important venoms and RA administration.

Viperidae snake envenomation from a highly complex hospital in southwestern Colombia

BackgroundSnake envenomation is a medical condition with high morbidity and mortality in southwestern Colombia. ObjectivesTo describe the characteristics of the envenomation caused by Viperidae snakes view in a highly complex hospital in Southwestern Colombia. MethodsA cross-sectional study was carried out. Patients treated for Viperidae snake envenomation from 2001 to 2020 in a Hospital Fundación Valle del Lili, Cali, Colombia, were studied. ResultsTwenty-eight patients were included. Envenomation was caused by the genera Bothrops, Bothriechis, Porthidium, and Bothrocophias. The median age was 37.7 (±20.6), and they were predominantly male (19, 68%). Bites occurred on the upper extremities in 16 (57%) patients. Pain (23, 81%) and edema (22, 78%) were the most common clinical symptoms. Thirteen (46%) patients presented coagulopathy. Prolonged prothrombin and activated partial thromboplastin times were common: (22, 78% and 15, 53%, respectively). Twenty (71%) patients were treated with polyvalent antivenom (median dose of 6 (2–15) vials). The median time between the accident and antivenom administration was 9 h (5.5–17). Door-to-needle time was 37.5 (0–62) min. Eighteen (64%) patients were admitted to the intensive care unit. Three (11%) patients had serum sickness. Seven (25%) developed infectious complications, four (14%) had surgery, one (3%) had compartment syndrome, one (3%) underwent amputation of the affected limb, and one (3%) patient died. ConclusionsLocal manifestations and coagulopathy were common clinical features. Polyvalent antivenom was an effective treatment for disease control. Significant complications were associated with delays in seeking medical care.

Immunological Cross-Reactivity and Preclinical Assessment of a Colombian Anticoral Antivenom against the Venoms of Three Micrurus Species.

Snakebite accident treatment requires the administration of antivenoms that provide efficacy and effectiveness against several snake venoms of the same genus or family. The low number of immunogenic components in venom mixtures that allow the production of antivenoms consequently gives them partial neutralization and a suboptimal pharmacological response. This study evaluates the immunorecognition and neutralizing efficacy of the polyvalent anticoral antivenom from the Instituto Nacional de Salud (INS) of Colombia against the heterologous endemic venoms of Micrurus medemi, and M. sangilensis, and M. helleri by assessing immunoreactivity through affinity chromatography, ELISA, Western blot, and neutralization capability. Immunorecognition towards the venoms of M. medemi and M. sangilensis showed values of 62% and 68% of the protein composition according to the immunoaffinity matrix, respectively. The analysis by Western blot depicted the highest recognition patterns for M. medemi, followed by M. sangilensis, and finally by M. helleri. These findings suggest that the venom compositions are closely related and exhibit similar recognition by the antivenom. According to enzyme immunoassays, M. helleri requires a higher amount of antivenom to achieve recognition than the others. Besides reinforcing the evaluation of INS antivenom capability, this work recommends the use of M. helleri in the production of Colombian antisera.