Hump-Nosed Pit Viper (Hypnale hypnale) Venom-Induced Irreversible Red Blood Cell Aggregation, Inhibition by Monovalent Anti-Venom and N-Acetylcysteine.

Envenomation by the Hypnale hypnale in the Western Ghats of India (particularly in the Malabar region of Kerala) and the subcontinent island nation of Sri Lanka is known to inflict devastating mortality and morbidity. Currently, H. hypnale bites in India are devoid of anti-venom regimens. A detailed characterization of the venom is essential to stress the need for therapeutic anti-venom. Notably, the deleterious effects of this venom on human blood cells have largely remained less explored. Therefore, in continuation of our previous study, in the present study, we envisioned investigating the effect of venom on the morphological and physiological properties of red blood cells (RBCs). The venom readily induced deleterious morphological changes and, finally, the aggregation of washed RBCs. The aggregation process was independent of the ROS and the intracellular Ca2+ ion concentration. Confocal and scanning electron microscopy (SEM) images revealed the loss of biconcave morphology and massive cytoskeletal disarray. Crenation or serrated plasma membrane projections were evenly distributed on the surface of the RBCs. The venom did not cause the formation of methemoglobin in washed RBCs but was significantly induced in whole blood. Venom did not affect glucose uptake and Na+/K+ -ATPase activity but inhibited glucose 6 phosphate dehydrogenase activity and decreased the fluidity of the plasma membrane. Venom-induced RBC aggregates exhibited pro-coagulant activity but without affecting platelet aggregation. In pre-incubation or co-treatment studies, none of the bioactive compounds, such as melatonin, curcumin, fisetin, berberine, and quercetin, sugars such as mannose and galactose, and therapeutic polyvalent anti-venoms (Bharat and VINS) were inhibited, whereas only N-acetylcysteine and H. hypnale monovalent anti-venom could inhibit venom-induced deleterious morphological changes and aggregation of RBCs. In post-treatment studies, paradoxically, none of the bioactives and anti-venoms, including N-acetylcysteine and H. hypnale monovalent anti-venom, reversed the venom-induced RBC aggregates.

Fasciotomy following North American pit viper envenomation in Texas 2004-2021.

INTRODUCTION: North American pit viper envenomation occurs over 4,000 times annually in the United States, with polyvalent Fab antivenom being the primary treatment. Fasciotomy is occasionally performed due to concerns about compartment syndrome. We utilized our direct access to Texas Poison Center Network data to create a new snakebite abstraction form and database on relevant available information between 2004 and 2021 and to identify, describe, and estimate the incidence of fasciotomy following pit viper envenomation in Texas. METHODS: We searched the Texas Poison Center Network database for cases during 2004-2021 using keywords such as fasciotomy, surgery, compartment pressure, and compartment syndrome. Descriptive statistics summarized the data. RESULTS: Of 16,911 reported envenomations, 0.69 percent involved fasciotomies (n = 117). Most common bite sites were digits/hands and lower extremities. Patients who underwent fasciotomy were typically male, aged 20-59, and 10 years younger than the total snakebite population. Only 6 percent of reported compartment syndrome cases had a compartment pressure measurement. Antivenom was administered in 101 (86.3 percent) cases, 92 (91.1 percent) of which received only Fab antivenom product. Patients with bites from rattlesnakes (47.9 percent) were associated with most fasciotomies. DISCUSSION: Our findings suggest a potential increase in snakebite exposures, accompanied by a decrease in fasciotomies. Overall, copperheads constituted the majority of snakebites, but most fasciotomies were from rattlesnake envenomations (47.9 percent). In this cohort, compartment syndrome diagnosis and decisions regarding fasciotomy were primarily based on clinical evaluation/surgeon expertise without compartment pressure measurements. Despite the efficacy of antivenom, only 86.3 percent of patients in our study received antivenom. CONCLUSIONS: Fasciotomy after North American pit viper envenomation in Texas is uncommon (0.69 percent) and has decreased over time, possibly due to increased antivenom use or surgeon comfort with nonsurgical management.

The effects of hyperbaric oxygen therapy on snake-bite-associated wounds in dogs.

OBJECTIVE: To assess the effect of hyperbaric oxygen therapy (HBOT) on Crotalinae envenomation-induced wound swelling and severity and pain in dogs, and to describe the safety and complications of HBOT. DESIGN: Prospective, randomized, controlled, blinded study (2017-2021). SETTING: University teaching hospital, private veterinary practice. ANIMALS: Thirty-six client-owned dogs presenting within 24 hours of a confirmed or suspected naturally occurring Crotalinae snake bite injury were enrolled between 2017 and 2021. INTERVENTIONS: In addition to the standard of care treatment, dogs received 2 interventions with either HBOT (n = 19) or control (n = 16) within 24 hours of hospital admission. Dogs receiving HBOT were pressurized over 15 minutes (1 psi/min), maintained at a target pressure of 2 atmosphere absolute (ATA) for 30 minutes, and decompressed over 15 minutes. Control dogs received 1 ATA for 1 hour. Local wound swelling, wound severity score, and pain score were assessed at admission, before and after each intervention, and at hospital discharge. MEASUREMENTS AND MAIN RESULTS: There was no significant difference in wound swelling (P = 0.414), severity score (P = 1.000), or pain score (P = 0.689) between HBOT and control groups. Pain decreased significantly over time regardless of the study intervention (P < 0.001). There were no major adverse effects associated with either study intervention. CONCLUSIONS: HBOT did not significantly alter the short-term recovery from Crotalinae envenomation in this study population. However, the study might be underpowered to detect a significant treatment effect.

Expression, Purification and Characterization of Recombinant Disintegrin from Gloydius Brevicaudus Venom in Escherichia Coli.

Disintegrins, a family of snake venom protein, which are capable of modulating the activity of integrins that play a fundamental role in the regulation of many physiological and pathological processes. The main purpose of this study is to obtain the recombinant disintegrin (r-DI) and evaluate its biological activity. In this study, we explored a high-level expression prokaryotic system and purification strategy for r-DI. Then, r-DI was treated to assay effects on cell growth, migration, and invasion. The affinity for the interactions of r-DI with integrin was determined using Surface plasmon resonance (SPR) analyses. The r-DI can be expressed in Escherichia coli and purified by one-step chromatography. The r-DI can inhibit B16F10 cells proliferation, migration, and invasion. Also, we found that r-DI could interact with the integrin αIIbß3 (GPIIb/IIIa). The r-DI can be expressed, purified, characterized through functional assays, and can also maintain strong biological activities. Thus, this study showed potential therapeutic effects of r-DI for further functional and structural studies.

Transient Hematotoxicity After Emerald Horned Pitviper (Ophryacus smaragdinus) Envenomation: A Case Report.

BACKGROUND: A minority of snake envenomations in the United States involve non-native snakes. In this report, we describe what we believe is the first documented human envenoming from an emerald horned pitviper, Ophryacus smaragdinus. CASE REPORT: A previously healthy 36-year-old woman was bitten on her left index finger by a captive emerald horned pitviper she was medicating at work. Swelling to the entire hand was present on emergency department arrival. She had no systemic symptoms and her initial laboratory studies were unremarkable. The affected limb was elevated. We administered five vials of Antivipmyn TRIⓇ (Bioclon), which specifically lists Ophryacus among the envenomations for which it is indicated. She developed pruritus and was treated with IV diphenhydramine and famotidine. Her swelling improved, but her repeat laboratory studies were notable for a platelet count of 102 K/µL and a fibrinogen level of 116 mg/dL. She declined additional antivenom because of the previous allergic reaction. She was admitted for further monitoring and pain control. Subsequent laboratory tests were better, but a small hemorrhagic bleb developed at the bite site. She was discharged the next day and followed up as an outpatient. Her swelling had resolved, her bleb had healed, and her laboratory studies continued to improve. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians may be required to treat bites from non-native snakes. Many of these bites will warrant treatment with non-U.S. Food and Drug Administration-approved antivenoms. Consultation with a regional poison center or medical toxicologist may be necessary to procure the proper antivenom.

Protobothrops jerdonii (Jerdon's pit viper) and Protobothrops himalayanus (Himalayan lance-headed pit viper) bites: Clinical report on envenomings from North-East India, managed through remote consultation by a national-level Poison control center.

Members of the genus Protobothrops are amongst the more than twenty-eight range-restricted Indian pit viper species. Their bites and envenomings are rarely documented from India. Pit viper envenomings can be challenging to treat in the Indian setting, since available antivenoms do not satisfactorily neutralize their venoms. Herein, we present the first Indian reports on bites and envenoming by Protobothrops jerdonii and Protobothrops himalayanus resulting in local effects, coagulopathy and acute kidney injury in the case of the former and possible mild, isolated coagulopathy in the case of the latter; and discuss management-related challenges in the context of absent specific antivenoms.

Incidence, clinical features, and risk factors of hemocoagulase-induced hypofibrinogenemia: A retrospective real-world study.

The objective of this study was to explore the real-world incidence, severity, clinical features, and potential risk factors associated with hypofibrinogenemia induced by hemocoagulase. Based on Chinese Hospital Pharmacovigilance System, a retrospective case-control study was conducted, enrolling hospitalized patients who received hemocoagulase for the treatment or prevention of hemorrhage in Weifang People's Hospital in China from January 2021 to May 2022. Univariate and multivariate logistic regression was performed to analyze the potential risk factors. Out of 10,397 hospitalized patients who received hemocoagulase, 341 patients showed positive triggers, with 235 patients ultimately conformed as hemocoagulase-associated hypofibrinogenemia. The system positive alarm rate was 68.91%, and the overall incidence of hemocoagulase-induced hypofibrinogenemia was 2.26%, predominantly characterized by mild to moderate severity levels. The incidence varied among the 4 types of hemocoagulase, with the highest incidence observed in hemocoagulase Agkistrodon Halys Pallas at 4.59%. The incidence of hemocoagulase from Deinagkistrodon acutus, Bothrops Atrox and Adder were 0.97%, 0.44% and 0.12%, respectively. Multivariate logistic regression analysis revealed that age (odds ratios [OR] = 177.328, P < .001), source of snake venom (OR = 5.641, P < .05), albumin (OR = 2.487, P < .001), and cumulative dosage (OR = 1.106, P < .001) were independent risk factors. Increased risk of hemocoagulase-related hypofibrinogenemia may be associated with children, elderly patients, low albumin levels, high cumulative doses and hemocoagulase from Agkistrodon Halys Pallas. Early recognition and close drug monitoring for these high-risk patients are vital in clinical practice.

In vitro immunoreactivity and in vivo neutralization of Trimeresurus gracilis venom with antivenoms targeting four pit viper species.

Snakebite envenomation is a significant global health issue that requires specific antivenom treatments. In Taiwan, available antivenoms target a variety of snakes, but none specifically target Trimeresurus gracilis, an endemic and protected species found in the high mountain areas of Taiwan. This study evaluated the effectiveness of existing antivenoms against T. gracilis venom, focusing on a bivalent antivenom developed for Trimeresurus stejnegeri and Protobothrops mucrosquamatus (TsPmAV), as well as monovalent antivenoms for Deinagkistrodon acutus (DaAV) and Gloydius brevicaudus (GbAV). Our research involved in vivo toxicity testing in mice and in vitro immunobinding experiments using (chaotropic) enzyme-linked immunosorbent assays, comparing venoms from four pit viper species (T. gracilis, T. stejnegeri, P. mucrosquamatus, and D. acutus) with three types of antivenoms. These findings indicate that TsPmAV partially neutralized T. gracilis venom, marginally surpassing the efficacy of DaAV. In vitro tests revealed that GbAV displayed higher binding capacities toward T. gracilis venom than TsPmAV or DaAV. Comparisons of electrophoretic profiles also reveal that T. gracilis venom has fewer snake venom C-type lectin like proteins than D. acutus, and has more P-I snake venom metalloproteases or fewer phospholipase A2 than G. brevicaudus, T. stejnegeri, or P. mucrosquamatus. This study highlights the need for antivenoms that specifically target T. gracilis, as current treatments using TsPmAV show limited effectiveness in neutralizing local effects in patients. These findings provide crucial insights into clinical treatment protocols and contribute to the understanding of the evolutionary adaptation of snake venom, aiding in the development of more effective antivenoms for human health.

Biochemical and toxicological profiles of venoms from an adult female South American bushmaster (Lachesis muta rhombeata) and her offspring.

In this work, we compared the biochemical and toxicological profiles of venoms from an adult female specimen of Lachesis muta rhombeata (South American bushmaster) and her seven offspring born in captivity, based on SDS-PAGE, RP-HPLC, enzymatic, coagulant, and hemorrhagic assays. Although adult and juvenile venoms showed comparable SDS-PAGE profiles, juveniles lacked some chromatographic peaks compared with adult venom. Adult venom had higher proteolytic (caseinolytic) activity than juvenile venoms (p < 0.05), but there were no significant inter-venom variations in the esterase, PLA2, phosphodiesterase and L-amino acid oxidase (LAAO) activities, although the latter activity was highly variable among the venoms. Juveniles displayed higher coagulant activity on human plasma, with a minimum coagulant dose ∼42% lower than the adult venom (p < 0.05), but there were no age-related differences in thrombin-like activity. Adult venom was more fibrinogenolytic (based on the rate of fibrinogen chain degradation) and hemorrhagic than juvenile venoms (p < 0.05). The effective dose of Bothrops/Lachesis antivenom (produced by the Instituto Butantan) needed to neutralize the coagulant activity was ∼57% greater for juvenile venoms (p < 0.05), whereas antivenom did not attenuate the thrombin-like activity of juvenile and adult venoms. Antivenom significantly reduced the hemorrhagic activity of adult venom (400 µg/kg, i. d.), but not that of juvenile venoms. Overall, these data indicate a compositional and functional ontogenetic shift in L. m. rhombeata venom.

The establishment and evaluation of a swine model of deinagkistrodon acutus snakebite envenomation.

OBJECTIVE: To establish a preclinical large-animal model of Deinagkistrodon acutus snakebite envenomation and evaluate its feasibility. METHODS: The venom of D. acutus (0 mg/kg, 1 mg/kg, 2 mg/kg, 5 mg/kg, or 10 mg/kg) was injected into the left biceps femoris of 11 male pigs. Then, the circumferences of the limbs were regularly measured, and changes in muscle injury biomarkers, blood parameters, coagulation function, vital organ function and injury biomarkers were regularly detected. At 24 h after venom injection, the animals were euthanized, and the pathological damage to the vital organs mentioned above was evaluated. RESULTS: The two pigs receiving 10 mg/kg and 5 mg/kg snake venom died at 8 h and 12 h after injection, respectively. The remaining pigs were equally divided into 0 mg/kg, 1 mg/kg, and 2 mg/kg snake venom groups, and all of them survived to 24 h after injection. Compared with the pigs receiving 0 mg/kg snake venom, the pigs receiving 1 mg/kg or 2 mg/kg snake venom exhibited significant abnormities, including limb swelling; increased muscle injury biomarker creatine kinase (CK) and coagulation function indicators prothrombin time and D-dimer; and decreased blood routine indicator platelet and coagulation function indicator fibrinogen. Moreover, significant abnormalities in myocardial and cerebral function and injury biomarkers in the heart, brain, liver, kidney and intestine were also observed. In particular, the abnormalities mentioned above were significantly obvious in those pigs receiving 2 mg/kg snake venom. Pathological evaluation revealed that the morphology of muscle, heart, brain, liver, kidney, and intestine in those pigs receiving 0 mg/kg snake venom was normal; however, pathological damage was observed in those pigs receiving 1 mg/kg and 2 mg/kg snake venom. Similarly, the pathological damage was more severe in those pigs receiving 2 mg/kg snake venom. CONCLUSION: The intramuscular injection of 2 mg/kg D. acutus venom seems to be an optimal dose for examining the preclinical efficacy of existing and novel therapeutics for treating D. acutus envenomation in pigs.

Comparative analysis of Deinagkistrodon acutus venom from Taiwan and China utilizing chromatographic, electrophoretic, and bioinformatic approaches, along with ELISA employing a monospecific antivenom.

Deinagkistrodon acutus is a medically important pitviper inhabiting mainly South China and Taiwan. The hemorrhagic effects of its envenoming are compatible to its venom, which is abundant in metalloproteases (svMPs) and C-type lectin-like proteins. In this study, we investigated geographic variations in the venom of D. acutus collected from Taiwan and four Mainland Chinese provinces: Fujian, Jiangxi, Anhui, and Hunan. The variations were assessed through high-performance liquid chromatography, non-metric multidimensional scaling analysis, gel electrophoresis, and enzyme-linked immunosorbent assay (ELISA) with a monospecific antivenom (DaMAV) generated against the Taiwanese D. acutus venom, and discussed based on venom-protein sequences in databases and literature related to D. acutus venom. Additionally, the cross-reactivity of DaMAV against Crotalus horridus and Calloselasma rhodostoma venoms was investigated. We noted differential abundances of D. acutus venom metalloproteases, C-type lectin-like proteins, and phospholipase A2, along with point mutations and selective expression of serine protease isoforms. The ELISA results revealed that the venom from Taiwan was more reactive toward Taiwanese DaMAV than the four Mainland Chinese venoms, consistent with chromatographic profile differences, whereas C. horridus venom presented moderate cross-reactivity with DaMAV. The observed immunoreactivities of these venom with DaMAV can be attributed to the high prevalence of their PIII-svMPs, which are the dominant antigens, and the conservation of PIII-svMP epitopes.

Envenomation by Eyelash Viper Bothriechis schlegelii (Berthold, 1846) in Southwestern Colombia.

INTRODUCTION: Bothriechis schlegelii is a Crotaline viperid species of Central America and Northern South America. The characteristics of its envenomation have not been well established. We present clinical characteristics of human cases evaluated and treated in a hospital in southwestern Colombia. METHODS: We evaluated data from patients who suffered Bothriechis schlegelii envenomation and were seen at Fundación Valle del Lili Hospital, Cali, Colombia between 2011 and 2022. RESULTS: Eight patients were included, with a median age of 24 years. Snakebites occurred in rural areas. Six (75%) patients were bitten on the upper extremities in relation to the arboreal habits of this animal. The most common symptoms were pain and edema (N = 8, 100%), ecchymoses (N = 2, 25%), and paresthesia (N = 2, 25%). The most common systemic findings were hypofibrinogenemia (N = 8, 100%) and prolonged prothrombin time in five patients (N = 5, 62.5%). All were treated with polyvalent antivenom for Colombian snakes, with a good response and outcome. CONCLUSIONS: Most bite sites from B. schlegelii were on the upper limbs. All patients had both local manifestations, including edema, pain, and systemic effects with hypofibrinogenemia, but none had systemic bleeding. Every patient received antivenom and had favorable outcomes.

Panicolytic-like effects of environment enrichment on male mice threatened by Bothrops jararaca lancehead pit vipers.

Environment enrichment (EE) is a well-known eustress model showing beneficial effects in different psychiatric diseases, but its positive properties in panic disorders are not yet established. The confrontation between prey and predator in complex arenas has been validated as a putative panic attack model. The principal aim of this work was to investigate the role of the EE on panic-like defensive responses elicited by mice threatened by venomous snakes. After 6 weeks of exposure either to an enriched or standard environments, 36 male mice were habituated in a complex polygonal arena for snakes containing an artificial burrow and elevated platforms for escape. The animals were confronted by Bothrops jararaca for 5 min, and the following antipredatory responses were recorded: defensive attention, stretched attend posture, flat back approach, prey versus predator interaction, oriented escape behavior, time spent in a safe place, and number of crossings. Mice threatened by snakes displayed several antipredatory reactions as compared to the exploratory behavior of those animals submitted to a nonthreatening situation (toy snake) in the same environment. Notably, EE causes anxiolytic- and panicolytic-like effects significantly decreasing the defensive attention and time spent in safe places and significantly increasing both prey versus predator interaction and exploratory behavior. In conclusion, our data demonstrate that EE can alter the processing of fear modulation regarding both anxiety- and panic-like responses in a dangerous condition, significantly modifying the decision-making defensive strategy.

Clinical Laboratory Investigations and Antivenom Administration after Malayan Pit Viper (Calloselasma rhodostoma) Envenoming: A Retrospective Study from Southernmost Thailand.

The Malayan pit viper (MPV: Calloselasma rhodostoma) is a medically important venomous snake causing numerous envenomations in Thailand. Administration of specific snake antivenom is the only effective treatment for MPV-envenomed patients. However, inappropriate administration or misuse of snake antivenom is problematic in some remote areas of tropical countries where the snakebite envenoming rate is notable. Currently, the indications for administration of MPV antivenom are focused mainly on hematological factors. These include 1) venous clotting time > 20 min, 2) unclotted 20-minute whole-blood clotting time, 3) international normalized ratio > 1.2, 4) platelet count < 50 × 103/µL, 5) systemic bleeding, and 6) impending compartment syndrome. We aimed to determine the association between laboratory data and antivenom administration in MPV-envenomed patients. A retrospective study of data from 2016 to 2021 in Narathiwat Province, the southernmost province in Thailand, was conducted. A total of 838 MPV-bitten patients were included in this study. Local effects and systemic effects were observed in 58.8% and 27.7% of patients, respectively. Coagulopathies, which range from abnormal blood clotting to systemic bleeding, represented the majority of systemic effects. Acute kidney injury developed in 2.5% of patients. In this study, 57.3% of patients were considered appropriate antivenom recipients. Interestingly, the present study revealed that local bleeding and mild to moderate thrombocytopenia became the independent factors for inappropriate use of MPV antivenom. Reeducation and supervision regarding the rational use of snake antivenom are needed to minimize the misuse of antivenom.

A bifurcation integrates information from many noisy ion channels and allows for milli-Kelvin thermal sensitivity in the snake pit organ.

In various biological systems, information from many noisy molecular receptors must be integrated into a collective response. A striking example is the thermal imaging organ of pit vipers. Single nerve fibers in the organ reliably respond to milli-Kelvin (mK) temperature increases, a thousand times more sensitive than their molecular sensors, thermo-transient receptor potential (TRP) ion channels. Here, we propose a mechanism for the integration of this molecular information. In our model, amplification arises due to proximity to a dynamical bifurcation, separating a regime with frequent and regular action potentials (APs), from a regime where APs are irregular and infrequent. Near the transition, AP frequency can have an extremely sharp dependence on temperature, naturally accounting for the thousand-fold amplification. Furthermore, close to the bifurcation, most of the information about temperature available in the TRP channels' kinetics can be read out from the times between consecutive APs even in the presence of readout noise. A key model prediction is that the coefficient of variation in the distribution of interspike times decreases with AP frequency, and quantitative comparison with experiments indeed suggests that nerve fibers of snakes are located very close to the bifurcation. While proximity to such bifurcation points typically requires fine-tuning of parameters, we propose that having feedback act from the order parameter (AP frequency) onto the control parameter robustly maintains the system in the vicinity of the bifurcation. This robustness suggests that similar feedback mechanisms might be found in other sensory systems which also need to detect tiny signals in a varying environment.

Clinical characteristics of snakebite patients attending a tertiary hospital in Hangzhou, southeast China.

BACKGROUND: Venomous snakebite is a neglected yet an important public health problem in China, and few studies have focused on them so far. The aim of this study is to investigate clinical characteristics of snakebites patients in a tertiary hospital in Hangzhou, southeast China. METHODS: A total of 416 snakebite cases were included in this retrospective study. The data were collected from the medical records including demographics, clinical manifestations, management and outcomes. RESULTS: Of the 416 patients with venomous snakebites, 248 were male, and the average age was 54.6 years. The majority of cases occurred in rural in May to September. Out of all the venomous bites, Gloydius brevicaudus accounted for the highest percentage (55.3%). Hands were the most vulnerable site to snakebites (47.4%). Patients had clinical manifestations of pain (100%), swelling (100%), wound necrosis (25.7%), hemorrhagic blister (18.3%), and blister (8.7%). Three hundred and ninety-two patients received antivenom administration, and most were treated within six hours after bites. Twenty-six patients received surgical treatments, and 90 patients developed venom-induced consumption coagulopathy. No deaths have occurred in this study. CONCLUSION: Hangzhou is one of the regions with high affecting of snakebites in China. The results of this study will increase the understanding of the clinical characteristics of venomous snakebites in Hangzhou area.

Structural, biochemical and immunochemical characterization of an acidic phospholipase A2 from Lachesis acrochorda (Viperidae: Crotalinae) venom.

Viperids of the genus Lachesis, also known as bushmasters, are capable of injecting great amounts of venom that cause severe envenomation incidents. Since phospholipases type A2 are mainly involved in edema and myonecrosis within the snakebite sites, in this work, the isolation, amino acid sequence and biochemical characterization of the first phospholipase type A2 from the venom of Lachesis acrochorda, named Lacro_PLA2, is described. Lacro_PLA2 is an acidic aspartic 49 calcium-dependent phospholipase A2 with 93% similarity to the L. stenophrys phospholipase. Lacro_PLA2 has a molecular mass of 13,969.7 Da and an experimental isoelectric point around 5.3. A combination of N-terminal Edman degradation and MS/MS spectrometry analyses revealed that Lacro_PLA2 contains 122 residues including 14 cysteines that form 7 disulfide bridges. A predicted 3D model shows a high resemblance to other viperid phospholipases. Nevertheless, immunochemical and phospholipase neutralization tests revealed a notorious level of immunorecognition of the isolated protein by two polyclonal antibodies from viperids from different genus, which suggest that Lacro_PLA2 resembles more to bothropic phospholipases. Lacro_PLA2 also showed significantly high edema activity when was injected into mice; so, it could be an alternative antigen in the development of antibodies against toxins of this group of viperids, seeking to improve commercial polyclonal antivenoms.

Incidence and Risk Factors for Wound Infections after Trimeresurus stejnegeri Snakebites in Taiwan.

Snakebite envenomation is a neglected tropical disease. Taiwan, with its subtropical and Southeast Asian environment, provides suitable habitat for several venomous snake species. Trimeresurus stejnegeri, an arboreal pit viper, is the most common cause of venomous snakebite in Taiwan. Trimeresurus stejnegeri envenomation can cause local swelling, occasional ecchymosis, and wound infection. The primary treatment of T. stejnegeri envenomation is the binary antivenom, vacuum freeze-dried F(ab')2 fragments of equine antibodies, against T. stejnegeri and Protobothrops mucrosquamatus. This study aimed to analyze the incidence of post-envenomation wound infections caused by T. stejnegeri based on data collected over a decade from institutions affiliated with the Chang Gung Memorial Hospital in Taiwan. A total of 254 patients were enrolled in this study. Clinical and laboratory data, treatment information, and patient outcomes were extracted from electronic medical records. Wound infection was associated with delay in antivenom initiation (adjusted odds ratio: 3.987; 95% CI: 1.406-11.302). The infection rates were 20.5%, 12.5%, 31.3%, and 48.1% for antivenom administration within 2 hours, 2-4 hours, 4-6 hours, and > 6 hours, respectively. Therefore, early initiation of antivenom treatment (within 6 hours) is recommended. Morganella morganii was cultured from wounds of the patients, whereas Enterobacter cloacae and Enterococcus faecalis were cultured from both the oral cavity of snakes and the wounds of the patients. For post-envenomation patients who develop a local infection, empiric antibiotics such as third-generation cephalosporins, quinolones, and piperacillin/tazobactam are recommended because snakebite wound infections are often polymicrobial in nature.

Prolonged venom-induced consumptive coagulopathy following Mangshan pit viper (Protobothrops mangshanensis) envenomation despite Hemato Polyvalent antivenom administration.

This case report summarizes an envenomation by the Mangshan pit viper (Protobothrops mangshanensis), a rare, endangered, venomous snake endemic to Mount Mang of China, and the first reported use of Hemato Polyvalent antivenom (HPAV) for this species. The snakebite occurred in a United States zoo to a 46-year-old male zookeeper. He presented via emergency medical services to a tertiary center after sustaining a single P. mangshanensis bite to the abdomen and was transported with antivenom from the zoo. Within 2 hours of envenomation, he developed oozing of sanguineous fluid and ecchymosis at the puncture site, and about 4 hours post-bite, was treated with HPAV. His coagulation profile fluctuated with the following pertinent peak/nadir laboratory values and corresponding hospital day (HD): undetectable fibrinogen levels, d-dimer 8.89 mg/L and 7.43 mg/L, and INR 2.97 and 1.46 on HD zero and three, respectively. Other peak/nadir values included hemoglobin 9.7 g/dL and creatinine phosphokinase 2410 U/L on HD four and platelets 81 × 109/L on HD seven. The patient received a total of 30 vials of HPAV over 5 days and 1 unit of cryoprecipitate on HD six. Upon discharge on HD eight, laboratory studies were normalizing, except for platelets, and edema stabilized. This case describes an acute, recurrent, and prolonged venom-induced consumptive coagulopathy despite prompt administration and repeated doses of HPAV.

Thromboembolic events following a pit viper bite from Protobothrops mucrosquamatus (Taiwan Habu): A report of two cases.

Protobothrops mucrosquamatus, also known as the Taiwan Habu, is a venomous snake prevalent in Taiwan. It is accountable for most snakebites in the region. The toxin of the Taiwan Habu has significant hemorrhagic potential. However, patients bitten by this snake often suffer more local injuries than systemic ones. This report presents two cases of individuals bitten by the Taiwan Habu who subsequently experienced thromboembolism. In the first case, an 88-year-old male, bitten on his fourth toe, suffered a cerebral infarction 32 hours post-bite. In the second case, an 82-year-old female, bitten on her ankle, experienced cardiac arrest 19 hours later. Both patients promptly received antivenom and showed no signs of coagulopathy either before or after the snakebite. However, elevated coagulation factor VIII levels were observed in the first case. Our aim is to understand the mechanism behind these thromboembolic events. This report emphasizes the unusually high level of coagulation factor VIIIa and highlights the need for further investigation into the mechanisms involved. Consequently, physicians should assess the risk of thromboembolic events in snakebite patients by evaluating coagulation factors during treatment.