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Antivenom has been the cornerstone of management for snake envenomation since its development and clinical use more than 100 years ago. Frequently used antivenoms are polyvalent antibodies, produced by immunizing animals. Like other protein drugs, antivenom has immunogenicity and may cause acute allergic reactions including 'anaphylaxis9 ranging from mild to life threatening reactions. Premedication with subcutaneous adrenaline has clear benefit evidenced by reduction of number and extent of these events. Due to diversities of venom composition, to be maximally effective, antivenoms should ideally be produced by using the venoms from species of local origin. For ensuring the ongoing safety and effectiveness of this antivenom, routine pharmacovigilance is necessary. Pharmacovigilance is a systematic, scientific study on adverse events that can be reported to concerned authority (Directorate General of Drug Administration (DGDA) in Bangladesh) by active or passive reporting. Introduction of pharmacovigilance will help to improve the monitoring and management of the AV related risks through identification and assessment of suspected drug adverse reactions, ineffectiveness, and other drug-related problems. Bangladesh drug regulatory authority (DGDA) encourages to report adverse events by health professionals following use of AV. At the same time need based distribution of AV and other logistics to the health care facilities across the country has to be established. Health authority should prioritize the need and take necessary actions to produce AV(s) using the venom from the locally collected medically important venomous snakes. Antivenom is an essential drug for managing a community emergency, snakebite envenomation. [ABSTRACT FROM AUTHOR]

The performance of dynamic body-feed filtration (DBF) in the removal of bulky solids produced during the manufacturing of snake antivenoms using the caprylic acid method was evaluated. For this purpose, diatomites with different filterability properties were compared in a bench-scale study to assess their effectiveness in removing the precipitated material formed after the addition of caprylic acid to equine hyperimmune plasma. C1000 diatomite at a concentration of 90 g/L of precipitated plasma showed the best performance. Then, the process was scaled up to three batches of 50 L of hyperimmune horse plasma. At this pilot scale, 108 ± 4% of the immunoglobulins present following plasma precipitation were recovered after DBF. The antivenoms generated using this procedure met quality specifications. When compared to open filtration systems commonly used at an industrial scale by many antivenom manufacturers, DBF has a similar yield and produces filtrates with comparable physicochemical characteristics. However, DBF ensures the microbiological quality of the primary clarification in a way that open systems cannot. This is because: 1) DBF is performed in a single-use closed device of depth filters which prevents microbial contamination, and 2) DBF removes bulky material in few minutes instead of the more than 24 h needed by open filtration systems, thus reducing the risk of contamination. It was concluded that DBF is a cost-effective, easily validated, and GMP-compliant alternative for primary clarification following caprylic acid precipitation of plasma in snake antivenom production.

Snakebite in the Middle East and North Africa (MENA) is a public health problem whose magnitude is not fully known. Several antivenoms are available in these regions, but these formulations are designed for restricted geographical settings. Many countries do not have local production of antivenoms and must access products whose clinical performance has not been demonstrated. We hypothesize that it is possible to unify the treatment for viperid snakebites of MENA in a single antivenom formulation. Hereby we describe the design, development and preclinical evaluation of an antivenom of broad geographical coverage for this region (MENAVip-ICP). We produced this antivenom from the plasma of horses immunized with eight medically important venoms of viperid snake species from MENA. For this, we used a strategy based on two stages: first, immunization of horses with North African (NA) venoms, followed by a second immunization stage, on the same horses, with MENA venoms. We purified antivenoms from both stages: the Anti-NA and the final product Anti-MENA (MENAVip-ICP). Anti-NA was considered as intermediate formulation and was purified with the intention to study the progression of the immunoglobulin immune response of the horses. Antivenoms from both stages neutralized lethal, hemorrhagic, and procoagulant activities of homologous venoms. Compared to Anti-NA, MENAVip-ICP improved the neutralization profile of intravenous lethality and in vitro procoagulant activities of venoms. A notable finding was the difference in the neutralization of lethality when MENAVip-ICP was assessed intraperitoneally versus intravenously in the murine model. Intraperitoneally, MENAVip-ICP appears more effective in neutralizing the lethality of all venoms. Furthermore, MENAVip-ICP neutralized the lethal activity of venoms of species from other regions of MENA, Central/East Asia, and Sub-Saharan Africa that were not included in the immunization protocol. Our results showed that MENAVip-ICP neutralizes the main toxic activities induced by viperid MENA venoms at the preclinical level. Consequently, it is a promising product that could be clinically assessed for the treatment of snakebite envenomings in this region.

Snakebite envenomation is a neglected tropical disease posing a high toll of mortality and morbidity in sub-Saharan Africa. Polyspecific antivenoms of broad effectiveness and specially designed for this region require a detailed understanding of the immunological features of the mamba snake (Dendroaspis spp.) venoms for the selection of the most appropriate antigen combination to produce antivenoms of wide neutralizing scope. Monospecific antisera were generated in rabbits against the venoms of the four species of mambas. The toxic effects of the immunization scheme in the animals were evaluated, antibody titers were estimated using immunochemical assays, and neutralization of lethal activity was assessed. By the end of the immunization schedule, rabbits showed normal values of the majority of hematological parameters tested. No muscle tissue damage was noticed, and no alterations in most serum chemical parameters were observed. Immunological analyses revealed a variable extent of cross-reactivity of the monospecific antisera against the heterologous venoms. The venoms of D. jamesoni and D. viridis generated the antisera with broader cross-reactivity by immunochemical parameters. The venoms of D. polylepis and D. viridis generated the antisera with better cross-neutralization of lethality, although the neutralizing ability of all antisera was lower than 0.16 mg venom/mL antiserum against either homologous or heterologous venoms. These experimental results must be scaled to large animal models used in antivenom manufacture at industrial level to assess whether these predictions are reproducible.

As injectable therapeutics, snake antivenoms must meet specifications for endotoxin content. The Limulus amebocyte lysate (LAL) test was used to evaluate the endotoxin content in several commercially available antivenoms released for clinical use. It was found that some products have endotoxin concentrations higher than the accepted limit for these contaminants. These results emphasize the need to include endotoxin determination as part of the routine evaluation of antivenoms by manufacturers and regulatory agencies.

ABSTRACT Background: Brazil ranks first in the number of snakebites in South America. A detailed analysis of these cases is required to improve the public health planning. In this study, we retrospectively examined the clinical and epidemiological profiles of snakebites in Maranhão between January 2009 and December 2019. Methods: Data were obtained from the compulsory notification forms provided by the Health Department of Maranhão. Results: A total of 17,658 cases were recorded during the study period. Most of the bites were from snakes belonging to the genus Bothrops. Medical care was mostly within three hours after the bite. Most cases were classified as mild and most victims recovered; however, 139 deaths were recorded. Most bites occurred among people aged 20-39 years, mainly among rural workers. The most frequent local clinical manifestations were pain, edema, and ecchymosis. The most common systemic clinical manifestations include neuroparalysis, vagal syndrome, and myolysis. Most snakebites occurred between January and March. The municipalities with the highest number of notifications were Buriticupu (936 cases), Arame (705 cases), and Grajaú (627 cases). Conclusions: The clinical profile of snakebites in Maranhão is similar to that observed in other states of Northeast Brazil. However, we found that some systemic manifestations are not compatible with the etiology of snakebites, which leads us to believe that the problem could be the lack of knowledge of the health professionals at the site of envenomation, who may not be ready for attendance, and an important lack of health centers with snake antivenom to treat snakebites.

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. [ABSTRACT FROM AUTHOR]

Snakebite in the Middle East and North Africa (MENA) is a public health problem whose magnitude is not fully known. Several antivenoms are available in these regions, but these formulations are designed for restricted geographical settings. Many countries do not have local production of antivenoms and must access products whose clinical performance has not been demonstrated. We hypothesize that it is possible to unify the treatment for viperid snakebites of MENA in a single antivenom formulation. Hereby we describe the design, development and preclinical evaluation of an antivenom of broad geographical coverage for this region (MENAVip-ICP). We produced this antivenom from the plasma of horses immunized with eight medically important venoms of viperid snake species from MENA. For this, we used a strategy based on two stages: first, immunization of horses with North African (NA) venoms, followed by a second immunization stage, on the same horses, with MENA venoms. We purified antivenoms from both stages: the Anti-NA and the final product Anti-MENA (MENAVip-ICP). Anti-NA was considered as intermediate formulation and was purified with the intention to study the progression of the immunoglobulin immune response of the horses. Antivenoms from both stages neutralized lethal, hemorrhagic, and procoagulant activities of homologous venoms. Compared to Anti-NA, MENAVip-ICP improved the neutralization profile of intravenous lethality and in vitro procoagulant activities of venoms. A notable finding was the difference in the neutralization of lethality when MENAVip-ICP was assessed intraperitoneally versus intravenously in the murine model. Intraperitoneally, MENAVip-ICP appears more effective in neutralizing the lethality of all venoms. Furthermore, MENAVip-ICP neutralized the lethal activity of venoms of species from other regions of MENA, Central/East Asia, and Sub-Saharan Africa that were not included in the immunization protocol. Our results showed that MENAVip-ICP neutralizes the main toxic activities induced by viperid MENA venoms at the preclinical level. Consequently, it is a promising product that could be clinically assessed for the treatment of snakebite envenomings in this region., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:All authors work in the Instituto Clodomiro Picado, Universidad de Costa Rica, where the horses were maintained and immunized, the antivenoms purified and all preclinical experiments carried out. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The performance of dynamic body-feed filtration (DBF) in the removal of bulky solids produced during the manufacturing of snake antivenoms using the caprylic acid method was evaluated. For this purpose, diatomites with different filterability properties were compared in a bench-scale study to assess their effectiveness in removing the precipitated material formed after the addition of caprylic acid to equine hyperimmune plasma. C1000 diatomite at a concentration of 90 g/L of precipitated plasma showed the best performance. Then, the process was scaled up to three batches of 50 L of hyperimmune horse plasma. At this pilot scale, 108 ± 4% of the immunoglobulins present following plasma precipitation were recovered after DBF. The antivenoms generated using this procedure met quality specifications. When compared to open filtration systems commonly used at an industrial scale by many antivenom manufacturers, DBF has a similar yield and produces filtrates with comparable physicochemical characteristics. However, DBF ensures the microbiological quality of the primary clarification in a way that open systems cannot. This is because: 1) DBF is performed in a single-use closed device of depth filters which prevents microbial contamination, and 2) DBF removes bulky material in few minutes instead of the more than 24 h needed by open filtration systems, thus reducing the risk of contamination. It was concluded that DBF is a cost-effective, easily validated, and GMP-compliant alternative for primary clarification following caprylic acid precipitation of plasma in snake antivenom production., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Guillermo Leon reports financial support was provided by 10.13039/100010269Wellcome Trust. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Background: Snakebite is considered a global health issue, especially in the Southeast Asian region. However, data regarding snakebite cases in Indonesia are still very limited. This study aimed to explore the venomous snakebite cases and the serum anti bisa ular (SABU) antivenom effect in treating venomous snakebite caused by other than the snake species indicated in currently available SABU antivenom formulas. Methods: The analytical descriptive method with a cross-sectional study design was conducted in 2021 using a total sampling from the medical records of 63 patients diagnosed with snakebite at Dr. Hasan Sadikin General Hospital Bandung from 2015 to 2019. Characteristics of patients, clinical manifestation, and correlation between snakes species and outcomes after treatment with or without administration of SABU antivenom were collected. Results: Out of 63 patients, males (79%) were predominant with an average age of 39 years. Fifty-six patients arrived at the Emergency Room less than 24 hours after the occurrence (89%). Most cases were categorized as grade 2 (41.%) where the upper extremities were commonly bitten the body area (64%). Edema (83%) was the most common manifestation. There was no correlation between snake antivenom administered to a specific snake species and the stated outcome (p=0.053), meaning that SABU antivenom might be an effective alternative to treat more types of snakebites. Conclusions: Snakebites are most common in males, attack the upper extremities, categorized as grade 2 with edema. Administration of SABU antivenom provides the similar outcome compared to the group caused by the Javan spitting cobra, Banded krait, and Malayan pit viper.

This work is aimed to bring insights on the potential sexual dimorphism differences on the venom composition of Bothrops asper and Crotalus simus to expand the knowledge of the venom variability that might improve the antivenom design. Biological characterization of venoms of each sex in both species did not show significant qualitative differences. Considerations on the sexual venom variations in these species are not relevant for choosing the snake donors for venom production. [Display omitted] • Venom sex-based biological activities of Bothrops asper and C. simus is reported. • No qualitative differences in venom sex-based composition between sexes were found. • Venom sex-based variations may not be relevant for antivenom production. [ABSTRACT FROM AUTHOR]

Snakebites from Protobothrops mucrosquamatus (Taiwan habus) and Viridovipera stejnegeri (green bamboo vipers) account for the most venomous snakebites in Taiwan. The bivalent freeze-dried hemorrhagic (FH) antivenom is employed to treat these two snakebite patients without a strict clinical trial. We evaluated the clinical usefulness of Taiwan bivalent freeze-dried hemorrhagic (FH) antivenom in Taiwan habu- and green bamboo viper-envenomed patients. We checked ELISA- based serum venom antigen levels before and after FH antivenom to evaluate FH’s ability to neutralize patients’ serum snake venom and its usefulness in reducing limb swelling after snakebites. Patients who had higher serum venom antigen levels had more severe limb swelling. Of the 33 enrolled patients, most of their snake venom antigen levels were undetected after the appliance of antivenom. Most enrolled patients (25/33) had their limb swelling subside within 12 h after antivenom treatment. The failure to reduce limb swelling was probably due to an inadequate antivenom dose applied in more severely envenomated patients. Our data indicate the feasibility of the FH antivenom in effectively eliminating venom and resolving the affected limb swelling caused by Taiwan habu and green bamboo viper bites.

Snakebite envenomation is a global health problem. This health problem asymmetrically affects rural populations in developing countries to such an extent that it recently has been listed as a priority neglected tropical disease (NTD). It is estimated that 5.4 million individuals are bitten by snakes each year, causing at least 2.7 million envenomations and more than 100,000 deaths each year. Ecuador has one of the highest snakebite envenomation incidence rates in Latin America, mostly in the coastal and Amazonian provinces. Envenomations in these regions are the result of bites primarily by species of snakes belonging to the Viperidae family. Ecuador was able to locally produce antivenoms, however serious flaws were revealed in the antivenom production process, leading to the decommissioning of the existing facility. In the interest of public health, we have summarized the political and social setbacks experienced by the antivenom serum production plant in Ecuador, while encouraging resuming local production of snake antivenom to improve the responsiveness of the already overburdened health system. [Display omitted] • This is the first attempt to describe the current situation of anti-venom production in Ecuador. • Ecuador is a country with 17.5 million people, and every year, 1,600 people are bitten by snakes. • The lack of antivenom production is linked to higher hospital admissions due to snakebites in Ecuador. • From 2015 to 2017, at least 42, 883 antivenom vials have been imported from Costa Rica due to the lack of local production. [ABSTRACT FROM AUTHOR]

In Uruguay, around 60 cases of snakebite accidents occur every year that need to be treated with specific antivenom. They are caused by two snakes of Bothrops genus: Bothrops alternatus and Bothrops pubescens. Snakebite accidents are mandatory notification events, allowing the acquisition of an accurate registry and a fluent communication with the health care services. The aim of this study is to analyze and report the doses administered to achieve the neutralization of the venom and the adverse reactions caused by snake antivenoms used in Uruguay in 2018, when a change was made in the type of antivenom available. In this year, Uruguay started to use the BIOL® antivenom (lyophilized) and this use coexists with traditional antivenom liquid forms (Vital Brazil and Malbran). The number of patients treated with heterologous BIOL® antivenom were 28 and the ones treated with heterologous solutions Malbran and Vital Brazil antivenoms were 21. The initial dose of BIOL antivenom was 8 vials instead of 4 vials regularly used with the others antivenoms and it achieved the neutralization of most cases (27/28 cases). Early adverse reactions were detected in 4 patients (3 in children) treated with BIOL antivenom and there were no adverse reactions in those treated with Malbran or Vital Brazil antivenoms. Lyophilized antivenom BIOL is being used widely in Uruguay without major complications.

Antivenom therapy is the only specific treatment for snakebite envenomation, and antivenom potency determination is key in the efficacy assurance quality control process. Nowadays, this process relies on the in vivo murine model - thus, the development of alternative in vitro methods is imperative. In the current study, the principle of the proposed method is the ability of Bothrops venom to induce cytotoxic effects in Vero cells, and the capacity to evaluate the inhibition of this cytotoxicity by the respective antivenom. After exposure to the venom/antivenom, the relative proportions of adherent (viable) cells were evaluated by direct staining with Coomassie Blue. The optical density (OD) of the lysed cell eluate was directly proportional to the number of adherent cells. This cytotoxicity-based alternative method could represent a potential candidate for validation as a replacement for the current in vivo test. The in vitro -determined cytotoxicity of the Brazilian Bothrops reference venom (expressed as the 50% effective concentration; EC 50 ) was 3.61 μg/ml; the in vitro -determined 50% inhibitory concentration (IC 50 ) of the Brazilian Bothrops reference antivenom was 0.133 μl/ml. From these two values, it was possible to calculate the potency of the reference antivenom. The results from the assays exhibited a good linear response, indicating that the method could be a potential candidate replacement method for use in antivenom quality control prior to lot release, subject to further validation., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

As injectable therapeutics, snake antivenoms must meet specifications for endotoxin content. The Limulus amebocyte lysate (LAL) test was used to evaluate the endotoxin content in several commercially available antivenoms released for clinical use. It was found that some products have endotoxin concentrations higher than the accepted limit for these contaminants. These results emphasize the need to include endotoxin determination as part of the routine evaluation of antivenoms by manufacturers and regulatory agencies., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Gabriela Solano, Adriana Sanchez, Mauren Villalta, Paola Sanchez, Gina Duran, Jose Maria Gutierrez and Guillrmo Leon work at Instituto Clodomiro Picado, where one of the antivenoms tested in this study is manufactured. Guillermo Leon Montero reports financial support was provided by 10.13039/100010269Wellcome Trust. Stuart Ainsworth reports financial support was provided by United Kingdom Research and Innovation., (© 2024 The Authors.)

Snake antivenom is the only specific treatment for snakebite envenoming, but life-threatening anaphylaxis is a severe side effect and drawback for the use of these typically mammalian serum products. The present study investigates the hypotheses whether serum IgE antibodies against the epitope galactose-alpha-1,3-galactose (α-gal) located on the heavy chain of non-primate mammalian antibodies are a possible cause for hypersensitivity reactions to snake antivenom. Serum samples from 55 patients with snakebite envenoming were obtained before administration of snake antivenom and tested for serum IgE (sIgE) against α-gal and total IgE. Early anaphylactic reactions (EARs) during the first 3 h after antivenom administration were classified into mild, moderate or severe and correlated with the presence of sIgE against α-gal. Fifteen (27%) out of 55 patients (37 male, 18 female, median 34 years, range 9–90 years) developed EARs after antivenom administration. Eleven, three and one patients had mild, moderate and severe EARs, respectively. Serum IgE against α-gal was detected in 17 patients (31%); in five (33%) out of 15 patients with EARs and in 12 (30%) out of 40 patients without EAR (Odds Ratio = 1.2; 95%-confidence interval: 0.3–4.2) with no correlation to severity. Although the prevalence of serum IgE against α-gal was high in the study population, very high levels of total IgE in the majority of patients question their clinical relevance and rather indicate unspecific sIgE binding instead of allergy. Lack of correlation between α-gal sIgE and EARs together with significantly increased total IgE levels suggest that sIgE against α-gal is not the major trigger for hypersensitivity reactions against snake antivenom.

Intact or fractionated immunoglobulins are used as snake antivenom to treat snake envenomation. Intravenously administered antivenom binds with snake toxins in the circulation and neutralizes the toxins. Binding of antivenom to venom in the central compartment prevents the distribution of venom to the peripheral tissues and enhances the elimination of venom. Reduction of antivenom concentration in the central compartment is due to both distribution to the peripheral tissues and elimination. Pharmacokinetics of snake antivenom varies among the three different types of immunoglobulins, namely whole IgG, F(ab’)2 and Fab. Pharmacokinetics of F(ab’)2 antivenom is best described by two compartment model with zero order input and linear elimination kinetics. Fab and F(ab’)2 antivenom with smaller molecular masses have a larger volume of distribution than whole IgG antivenom. A biphasic decline of intravenously administered whole IgG and F(ab’)2 antivenom has been observed.

Background: This report describes 17 cases of red‐bellied black snake envenomation (RBBS; Pseudechis porphyriacus) in dogs in south‐eastern Queensland. Patients were prospectively enrolled for the treatment with a new tiger‐brown snake antivenom 8000 units, (TBAV; Padula Serums Pty Ltd, VIC, Australia). Case Report: Clinical diagnosis of RBBS envenomation was made by either snake venom detection kit, snake identification using scale counting, or owner observed dog‐snake interaction in patients with clinical signs of envenomation. An RBBS venom antigen sandwich ELISA was used to retrospectively quantify venom levels in frozen serum and urine. Mechanical ventilation was required in 11% (2/17) patients, whole blood transfusion in 12% (2/17), tissue swelling at the bite site occurred in 53% (9/17) and facial palsy in 12% (2/17). One dog was euthanised, and overall, 94% (16/17) survived to hospital discharge. Clinicopathological changes pre‐TBAV included variable haemolysis, increased CK, pigmenturia and mildly prolonged active clotting time with a median of 134 s (n = 13, range 91–206 s). Haematological profiles post envenomation revealed anaemia (6/6) and spherocytosis (5/5), which resolved without the use of corticosteroids. Pre‐TBAV, median RBBS venom antigen concentration was 22.6 ng/mL (n = 15, range 2–128) in serum and 58 ng/mL (range 1–452) in urine; RBBS venom antigen was undetectable in serum post‐TBAV in all patients. Conclusion: Some RBBS envenomed dogs required, critical care including mechanical ventilation, blood transfusion, additional antivenom and prolonged hospitalisation. TBAV was effective with excellent prognosis despite stated specificity for tiger and brown snake. [ABSTRACT FROM AUTHOR]

We present a clinical case of a snake bite in 8-year-old girl, who was hospitalized at the intensive care unit of Ternopil Regional Children’s Clinical Hospital. The peculiarity of this case report is the domination of pain syndrome and a significant lymphostasis in the bite site, the absence of systemic lesion. It is necessary to raise public awareness about possible snake bites. Bites in children are particularly dangerous due to the fact that children spend a lot of time barefoot in the open area.

Snakebite envenomation is a neglected tropical disease posing a high toll of mortality and morbidity in sub-Saharan Africa. Polyspecific antivenoms of broad effectiveness and specially designed for this region require a detailed understanding of the immunological features of the mamba snake ( Dendroaspis spp.) venoms for the selection of the most appropriate antigen combination to produce antivenoms of wide neutralizing scope. Monospecific antisera were generated in rabbits against the venoms of the four species of mambas. The toxic effects of the immunization scheme in the animals were evaluated, antibody titers were estimated using immunochemical assays, and neutralization of lethal activity was assessed. By the end of the immunization schedule, rabbits showed normal values of the majority of hematological parameters tested. No muscle tissue damage was noticed, and no alterations in most serum chemical parameters were observed. Immunological analyses revealed a variable extent of cross-reactivity of the monospecific antisera against the heterologous venoms. The venoms of D. jamesoni and D. viridis generated the antisera with broader cross-reactivity by immunochemical parameters. The venoms of D. polylepis and D. viridis generated the antisera with better cross-neutralization of lethality, although the neutralizing ability of all antisera was lower than 0.16 mg venom/mL antiserum against either homologous or heterologous venoms. These experimental results must be scaled to large animal models used in antivenom manufacture at industrial level to assess whether these predictions are reproducible., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Guillermo León reports financial support and article publishing charges were provided by 10.13039/100010269Wellcome Trust. José María Gutiérrez reports financial support was provided by 10.13039/100010269Wellcome Trust. Guillermo León reports financial support was provided by Research Foundation of the 10.13039/501100005298University of Costa Rica. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Abstract This work evaluated the feasibility of using toxoids obtained by gamma radiation in the production of antivenoms in small and large animals. Mixtures of African snake venoms from viperids or elapids were used. The viperid mixture contained the crude venom of five species of the genera Echis and Bitis , while the elapid mixture contained the crude venom of six species of the genera Naja and Dendroaspis. The viperid mixture had an LD 50 of 1.25 mg/kg in mice, and the elapid mixture had an LD 50 of 0.46 mg/kg. Both viper and elapid aqueous mixtures were subjected to Cobalt-60 gamma irradiation in three physical states: lyophilized, frozen and liquid. Radiation doses ranged from 0.5 to 100 kGy. The LD 50 s of the lyophilized and frozen mixtures of both viperid and elapid mixtures remained unaltered with radiation doses as high as 100 kGy; nevertheless, in the liquid state, doses of 3.5 and 5.5 kGy reduced the venom toxicity of both the viperid and elapid mixtures to 7.25 mg/kg and 1.74 mg/kg; less toxic by factors of 5.8 and 3.8, respectively. Groups of four rabbits and three horses were immunized with either irradiated or non-irradiated mixtures. In vitro and in vivo analysis of the rabbit and horse sera revealed that neutralizing antibodies were produced against both irradiated (toxoids) and native venom mixtures. None of the animals used in this study, either immunized with native venom or toxoids, developed severe local effects due to the application of venoms mixtures. Gamma-irradiated detoxified venoms mixtures, under well-controlled and studied conditions, could be a practical alternative for the production of polyvalent equine serum with high neutralization potency against snake venoms. Highlights • Mixtures of Viperid and Elapid venom were detoxified using gamma radiation. • Venoms were more sensitive to gamma radiation in liquid state than frozen and lyophilized. • Toxoids were immunogenic in rabbit and horses. • Toxoid antisera were as effective in producing neutralizing antibodies as native mixtures. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Snake bites are a silent public health problem in Kenya. Previous studies on snake bites in the country have mainly focused on identifying offending snake species, assessing the severity of envenomation and testing the efficacy of antivenom. Factors associated with snake bites in the country are yet to be fully understood. The aim of this work was to determine pharmaco-epidemiological factors associated with snake bites in areas of Kenya where incidence, severity and species responsible for snake bites have been reported. METHODS: Kakamega provincial hospital, Kabarnet, Kapenguria and, Makueni district hospitals were selected as study sites based on previous findings on incidence, severity and species responsible for snake bites in catchment areas of these hospitals. Persistent newspaper reports of snake bites in these areas and distribution of snakes in Kenya were also considered. Cases of snake bites reported between 2007-2009 were retrospectively reviewed and data on incidence, age, site of the bites, time of bite and antivenom use was collected. RESULTS: 176 bites were captured, 91 of which occurred in 2009. Individual incidence was between 2.7/100,000/year and 6.7/100,000/year. Bites peaked in the 1-15 year age group while 132/176 bites were in the lower limb area and 49/176 victims received antivenom. Most bites occurred during the dry season, in the bush and in the evening. Overall mortality was 2.27%. CONCLUSION: there is a need to sensitize the Kenyan public and healthcare personnel on preventive measures, first aid and treatment of snake bites.

The use of conventional approved snake antivenom is the most reliable snake envenomotherapy at the moment. However, because of post-treatment hypersensitivity reactions sometimes caused by large doses of snake antivenoms, the treatment of snake poisoning needs to be reviewed. The effective dose fifty (ED50) of snake antivenom was calculated for 11 American pit viper envenomation as reported by Consroe et al. Four different ED50 formulas were used to determine effective dose fifty of snake antivenom against LD50 of the snake venoms using intravenous route. The findings revealed that snake envenomotherapy is in monotonic dose-response fashion with each formular producing ED50 value for specific snake. The difference in values may be due to species of snakes and the types of ED50 formula used. All the ED50 formulas with the LD50 as numerator yielded higher effective therapeutic dose of snake antivenoms and corresponding higher LD50 values of snake venoms. The lower the denominator, the lower the LD50 and the ED50 value, and the lower the chance of hypersensitivity reaction, but the higher may be the chance of the snake antivenom failure. Therefore, Saganuwan’s formula LD50=ED503xWax10−4, whereas Wa is weight of animal, could produce effective envenometherapy with low chance of hypersensitivity reactions. [ABSTRACT FROM AUTHOR]

This case report describes a dog envenomed by a red-bellied black snake (RBBS; Pseudechis porphriacus ) that experienced severe and life-threatening haemolysis. The dog presented with hypersalivation, facial swelling, mildly prolonged activated clotting time and the absence of neurological deficits. Envenomation was confirmed by positive identification of the snake and retrospective measurement of RBBS specific venom antigen (24 ng/mL) in serum. The dog was initially hospitalised, treated with intravenous fluids and one vial of tiger-brown snake antivenom which is recommended for RBBS envenomation in Australia. However, after 3.5 d the dog's PCV had declined to 15% and the dog was dull and tachycardic. A second vial of tiger-brown antivenom followed by a packed red blood cell transfusion was administered. A rapid clinical improvement within 12 h was observed. No free RBBS venom was detected in serum at any time point after the first vial of antivenom. Longitudinal haematology and biochemical profiling was performed to 62 d post-envenomation and revealed a gradual recovery in the haematocrit to normal reference range. Spherocyte numbers on blood smear were highest at 5 d post-envenomation and gradually declined to undetectable after 62 d. This case highlights the potential for unpredictable, severe and life-threatening anaemia resulting from RBBS envenomation in dogs. [ABSTRACT FROM AUTHOR]

This report describes a series of ten cases of fulminant pulmonary haemorrhage in dogs following envenomation by the eastern brown snake ( Pseudonaja textilis ) in south eastern Queensland, Australia. All cases were presented for veterinary treatment during 2011–2018 at a specialist veterinary emergency centre. Each case received prompt antivenom treatment and supportive care. Pulmonary haemorrhage was diagnosed based on clinical examination; overt haemoptysis; thoracic radiographic demonstration of a diffuse alveolar pattern; and, the presence of venom induced consumptive coagulopathy. The median elapsed time from hospital admission to onset of haemoptysis was 2 h (range 0–18 h). In 80% (8/10) of cases endotracheal intubation was required, whilst 20% (2/10) were successfully treated with mask oxygen supplementation alone, and 40% (4/10) received mechanical ventilation; but only 25% (1/4) of these survived to hospital discharge. Fresh frozen canine plasma was administered to 70% (7/10) of cases and 43% (3/7) of these survived. Of the total number of cases presented for treatment, 30% (3/10) survived to hospital discharge, 60% (6/10) were euthanised due to poor prognosis and 10% (1/10) died from cardiac arrest. Initial serum brown snake venom antigen levels were retrospectively measured from frozen serum samples by venom specific sandwich ELISA in two dogs at 154 ng/mL (survived) and 3607 ng/mL (euthanised); no free venom was detected post-antivenom. Dogs that survived were discharged from hospital without apparent complications. Pulmonary haemorrhage is an uncommon event following envenomation by P. textilis in dogs and has not been described in similarly envenomed humans. This case series highlights the potential for fulminant and fatal pulmonary haemorrhage in dogs following eastern brown snake envenomation. [ABSTRACT FROM AUTHOR]

Snakebite envenoming represents a major issue in rural areas of tropical and subtropical regions across sub-Saharan Africa, South to Southeast Asia, Latin America and Oceania. Antivenoms constitute the only scientifically validated therapy for snakebite envenomings, provided they are safe, effective, affordable, accessible and administered appropriately. However, the lack of financial incentives in a technology that has remained relatively unchanged for more than a century, has contributed to some manufacturers leaving the market and others downscaling production or increasing the prices, leading to a decline in the availability and accessibility for these life-saving antidotes to millions of rural poor most at risk from snakebites in low income countries. The shortage of antivenoms can be significantly alleviated by optimizing the use of current antivenoms (through the assessment of their specific and paraspecific efficacy against the different medically relevant homologous and heterologous snake venoms) and by generating novel polyspecific antivenoms exhibiting broad clinical spectrum and wide geographic distribution range. Research on venoms has been continuously enhanced by advances in technology. Particularly, the last decade has witnessed the development of omics strategies for unravelling the toxin composition of venoms (“venomics”) and to assess the immunorecognition profile of antivenoms (“antivenomics”). Here, we review recent developments and reflect on near future innovations that promise to revolutionize the mutually enlightening relationship between evolutionary and translational venomics. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Ophidian accidents are a serious public health problem in Argentina; the Bothrops species is responsible for 97% of these accidents, and in particular, B. diporus is responsible for 80% of them. In the northeast of the country (Corrientes Provinces), Cissampelos pareira L. (Menispermaceae) is commonly used against the venom of B. diporus; its use is described in almost all ethnobotanical literature from countries where the plant grows. Aim of the study In this study, the in vitro and in vivo antivenom activities of C. pareira extracts were evaluated against B. diporus venom, with a particular focus on the local effects associated with envenoming. The seasonal influence on the chemical composition of the active extracts was also studied, in order determine the associated range of variability and its influence on the antivenom activity. Materials and methods This research was conducted using aerial parts (leaves, flowers, tender stems) and roots of Cissampelos pareira collected from two different phytogeographic regions of Corrientes (Argentina); Paso de la Patria and Lomas de Vallejos. In addition, to perform a seasonal analysis and to evaluate the metabolic stability, material was collected at three different growth stages. In vivo and in vitro anti-snake venom activities were tested, and a bio-guided chromatographic separation was performed in order to determine the active chemicals involved. The fractions obtained were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and the chemical profile of the most active constituent was analyzed by ultra high-performance liquid chromatography coupled to quadrupole/high-resolution mass spectrometry (Q-Orbitrap). (UHPLC-MS). Results The alcoholic extract was found to be the most active The bio-guided fractionation allowed selection one fraction to be analyzed by UHPLC-MS in order to identify the components responsible for the activities found; this identified five possible flavonoids. Conclusions Our studies of the activity of C. pareira against the venom of B. diporus have confirmed that this species possesses inhibitory effects in both in vitro and in vivo models. Moreover, the present data demonstrate that certain flavonoids may mitigate some of the venom-induced local tissue damage. [ABSTRACT FROM AUTHOR]

Background: Capillary leak syndrome (CLS) has been previously observed as a complication of Daboia russelii bite but not clearly defined or studied in length. This observational case-control study evaluates the mortality along with associated clinical and laboratory features. Methods: Twenty-five patients who developed CLS were compared with 25 patients without CLS following Daboia russelii (Russell's viper) bite. Results: Development of CLS is associated with a significantly high risk of mortality; 11 (44%) patients with CLS died compared with 1 (4%) control (odds ratio 18.8 [95% confidence interval 2.2 to 161.99], p=0.002). Diseasedefining manifestations included myalgia (22 [88%]), thirst (20 [80%]), parotid swelling (15 [60%]), conjunctival chemosis (19 [76%]) and hypotension (22 [88%]), which were unobserved in controls. Although several clinical and laboratory parameters were found to be predictive for development of CLS in univariate analysis, none of them had independent predictive value in multivariate analysis. Similarly, development of parotid swelling was the only factor with independent predictive value for mortality in multivariate analysis. Even though the number of vials of snake antivenom used is more in CLS, it seems unlikely to improve the mortality in CLS. Conclusions: This study proves that CLS is a well-defined complication of Russell's viper bite with high mortality but with clear predictors for the development of CLS and mortality. [ABSTRACT FROM AUTHOR]

Introduction: Snake bites are a silent public health problem in Kenya. Previous studies on snake bites in the country have mainly focused on identifying offending snake species, assessing the severity of envenomation and testing the efficacy of antivenom. Factors associated with snake bites in the country are yet to be fully understood. The aim of this work was to determine pharmaco-epidemiological factors associated with snake bites in areas of Kenya where incidence, severity and species responsible for snake bites have been reported. Methods: Kakamega provincial hospital, Kabarnet, Kapenguria and, Makueni district hospitals were selected as study sites based on previous findings on incidence, severity and species responsible for snake bites in catchment areas of these hospitals. Persistent newspaper reports of snake bites in these areas and distribution of snakes in Kenya were also considered. Cases of snake bites reported between 2007-2009 were retrospectively reviewed and data on incidence, age, site of the bites, time of bite and antivenom use was collected. Results: 176 bites were captured, 91 of which occurred in 2009. Individual incidence was between 2.7/100,000/year and 6.7/100,000/year. Bites peaked in the 1-15 year age group while 132/176 bites were in the lower limb area and 49/176 victims received antivenom. Most bites occurred during the dry season, in the bush and in the evening. Overall mortality was 2.27%. Conclusion: There is a need to sensitize the Kenyan public and healthcare personnel on preventive measures, first aid and treatment of snake bites. [ABSTRACT FROM AUTHOR]

A mixture of the venoms of Bothrops asper , Crotalus simus and Lachesis stenophrys is used as immunogen to produce the polyspecific Central American antivenom (PoliVal-ICP). In this work, we studied the ability of each of these venoms to modulate the antibody response induced by the other two venoms included in the immunization mixture. For that, equine monospecific, bispecific and polyspecific antivenoms were prepared and compared regarding their ability to neutralize the phospholipase A 2 , coagulant and lethal activities of each venom, and their anti-venom antibodies concentration. Results indicate that there is low cross-reactivity and cross-neutralization between venoms of B. asper , C. simus and L. stenophrys , hence justifying the use of all of them as immunogens for the production of the Central American antivenom. It was also found that the venom of B. asper reduces the anti-crotalic response while the venom of C. simus does not affect the anti-bothropic response. On the other hand, the venoms of B. asper and C. simus increase the anti-lachesic response, and L. stenoprhys venom reduced both the anti-bothropic and anti-crotalic responses. On the basis of these results, the immunization strategy can be adjusted by preventing or taking advantage of cross-immunomodulation between venoms, in order to maximize the antibody response towards all venoms. Immune responses can be improved by injecting horses with several immunogen mixtures, composed by one or two of the three venoms, and administering them at different times during the immunization, eventually generating a high titer against the three venoms. Our results suggest that addressing the issue of immunomodulation by venoms might improve antivenom manufacture worldwide. [ABSTRACT FROM AUTHOR]

This report describes the diagnosis and treatment of 16 confirmed cases of snakebite from the Australian eastern brown snake ( Pseudonaja textilis ) in dogs and cats. The clinical signs, brown snake venom antigen concentrations, coagulation parameters, and treatment outcomes following administration of an experimental caprylic acid fractionated bivalent whole IgG antivenom are documented. A brown snake venom antigen specific sandwich ELISA was used to retrospectively quantify venom levels in serum and urine. The characteristic clinical signs of envenomation in all cases were neurotoxicity to a variable extent and coagulation disturbances. The median serum venom concentration at presentation was 122 ng/mL and ranged from 1.9 to 3607 ng/mL. The median urine venom concentration at presentation was 55 ng/mL and ranged from 3.3 to 2604 ng/mL. Mechanical ventilation was used to successfully support respiration in three severely paralysed cases for 1–30 h. In four cases where serum samples were available post-antivenom treatment, venom was no longer detectable. Coagulation parameters measured on citrated plasma samples collected prior to antivenom from each case were abnormally prolonged to variable degrees in all cases. Three cases (2 dogs; 1 cat) were euthanized within four hours of presentation for either cost based reasons (2) or poor prognosis (1). One dog developed massive and potentially fatal pulmonary haemorrhage and was euthanazed. In vitro testing of the venom procoagulant neutralising efficacy of the experimental antivenom demonstrated it was 9.6–72 times more effective when compared to two other commercial veterinary antivenom products. This is the first detailed report of a case series of P. textilis envenomation in dogs and cats. The envenomation syndrome in dogs and cats differed to that reported humans, dominated by neurotoxicity and coagulopathy; unlike in humans, where coagulopathy is of primary clinical significance. [ABSTRACT FROM AUTHOR]

Snakebite in dogs from Pseudechis porphyriacus (red-bellied black snake; RBBS) is a common envenomation treated by veterinarians in Australia where this snake occurs. This case report describes the successful treatment of a clinically severe RBBS envenomation in a dog with an experimental bivalent equine whole IgG antivenom and mechanical ventilation, following its presentation in a cyanotic state. The cause of the cyanosis and respiratory distress was considered due to paralysis from neurotoxins in RBBS venom. The dog was treated with two vials of bivalent antivenom, each containing sufficient antivenom to neutralise the lethal effects of 40 mg of tiger snake ( Notechis sp) and 40 mg of brown snake ( Pseudonaja sp) venom. Hypoxaemia (Sp0 2 of 75%) and hypercapnia (PaCO 2 of 61 mmHg) indicated the need for mechanical ventilation (MV) to prevent imminent death. The dog was anaesthetised using total intravenous anaesthesia and MV used for 18 h. Following discontinuation of MV, it resumed spontaneous breathing thereafter and made a complete recovery. Serum biochemistry revealed a significant myopathy with elevated CK and AST levels, peaking approximately 48 h post-treatment. Elevated liver enzymes, suggestive of hypoxic liver injury, were detected during the period of hospitalisation. The dog represented approximately one week after hospital discharge because of inappetence and mild hepatopathy, which resolved spontaneously by 30 d post-treatment. A mild coagulopathy was initially present which resolved within 24 h following antivenom treatment. At initial presentation, RBBS venom antigen was detected by sandwich ELISA in urine and serum. Free RBBS venom antigen was not detected post-antivenom treatment. Human cases of RBBS requiring ventilatory support are rare. This unusual case of RBBS envenomation in a dog highlights its potential clinical severity in dogs, and the need for early, aggressive, MV to achieve a successful outcome in cyanosed and clinically severe cases. [ABSTRACT FROM AUTHOR]

The common European adder, Vipera berus berus, is a medically relevant species, which is widely distributed in Russia and thus, is responsible for most snakebite accidents in Russia. We have investigated the toxic and enzymatic activities and have determined the proteomic composition of its venom. Phospholipases A2 (PLA2, 25.3% of the venom proteome), serine proteinases (SVSP, 16.2%), metalloproteinases (SVMP, 17.2%), vasoactive peptides (bradykinin-potentiating peptides (BPPs), 9.5% and C-type natriuretic peptides (C-NAP, 7.8%), cysteine-rich secretory protein (CRISP, 8%) and L-amino acid oxidase (LAO, 7.3%) represent the major toxin classes found in V. b. berus (Russia) venom. This study was also designed to assess the in vivo and in vitro preclinical efficacy of the Russian Microgen antivenom in neutralizing the main effects of V. b. berus venom. The results show that this antivenom is capable of neutralizing the lethal, hemorrhagic and PLA2 activities. Third-generation antivenomics was applied to quantify the toxin-recognition landscape and the maximal binding capacity of the antivenom for each component of the venom. The antivenomics analysis revealed that 6.24% of the anti-V. b. berus F(ab’)2 molecules fraction are toxin-binding antibodies, 60% of which represent clinically relevant antivenom molecules.

Subcutaneous administration of a low dose of adrenaline is used to prevent the early adverse reactions (EARs) induced by snake antivenoms. We used a rabbit model to study the effect of premedication with adrenaline on the potential of antivenoms to exert therapeutic effects and to induce late adverse reactions. We found that premedication with adrenaline did not change the heart rate or blood pressure of normal rabbits, but reduced the rise in temperature in rabbits previously sensitized with antivenom. Pharmacokinetic studies suggest that premedication with adrenaline does not affect the ability of the antivenom to exert the initial control of envenomation nor the susceptibility of rabbits to develop recurrence of antigenemia and envenomation. Our results also indicate that it is unlikely that premedication with adrenaline decreases the incidence of late reactions induced by the antivenom administration, although it reduces the extent of early reactions. [ABSTRACT FROM AUTHOR]

This study assessed the protective effect of active immunization of cattle to prevent the envenomation induced by B. asper venom. Two groups of oxen were immunized with a bothropic toxoid and challenged by an intramuscular injection of either 10 or 50 mg B. asper venom, to induce moderate or severe envenomations, respectively. Non-immunized oxen were used as controls. It was found that immunized oxen developed local edema similar to those observed in non-immunized animals. However, systemic effects were totally prevented in immunized oxen challenged with 10 mg venom, and therefore antivenom treatment was not required. When immunized oxen were challenged with 50 mg venom, coagulopathy was manifested 3–16 h later than in non-immunized oxen, demonstrating a delay in the onset of systemic envenomation. In these animals, active immunization did not eliminate the need for antivenom treatment, but increased the time lapse in which antivenom administration is still effective. All experimentally envenomed oxen completely recovered after a week following venom injection. Our results suggest that immunization of cattle with a bothropic toxoid prevents the development of systemic effects in moderate envenomations by B. asper , but does not abrogate these effects in severe envenomation. [ABSTRACT FROM AUTHOR]