The Puff Adder (Bitis arietans) is a viper native to Africa and the Middle East. Envenomation by this species often requires the administration of appropriate antivenom in order to achieve a favorable outcome. A patient was bitten in both hands by a captive B. arietans presented to a teaching hospital in Malaysia. The patient developed painful progressive swelling on both limbs that extended to the chest, hypotension, hypokalemia with worsening anemia, thrombocytopenia, coagulopathy, and severe metabolic acidosis. The patient was managed supportively while waiting for the appropriate antivenom, Antivipmyn-Africa, from the Singapore Zoo. The patient developed cardiorespiratory arrest twice and did not recover from the second. The patient was pronounced dead 23 hours post-incident. The local unavailability of the appropriate antivenom may be the most important factor that contributed to the patient's death. There is also a need to amend the Malaysian Wildlife Act in order to prevent such cases from recurring.
Not all pit viper species are present in every state of Malaysia and their distribution varies according to altitude. There is limited information on pit viper bite incidence and its geographical distribution. This was a cross-sectional study of confirmed pit viper bite cases referred to Remote Envenomation Consultancy Services (RECS) from January 2017 to December 2020. Data was collected following the approval of institutional research ethics committee. Universal sampling methods were used. Confirmed pit viper bite cases in each state, geographical location and the antivenom used were reported. A total of 523 confirmed pit viper bite injuries occurred over the 4-year study period. The majority were Malaysians, male and young adults. Most were non-occupational related (83.9%) and involved the upper limbs (46.8%). The commonest pit viper species involved was Trimeresurus purpureomaculatus (23.7%). Green pit viper antivenom (GPAV) was the most frequent antivenom used (n = 51) with the majority of patients requiring only one dose (3 vials). This study provides a better appreciation of indigenous pit viper species distribution for each state and reflects the requirement of appropriate antivenom to be stocked in each state or district hospital.
Hypnale hypnale (hump-nosed pit viper) is a medically important venomous snake in Sri Lanka and Southwestern India. Bite of this snake may result in hemostatic dysfunction, acute kidney injury and death. Clinical studies indicated that the locally available polyvalent antivenoms produced in India are not effective against hump-nosed pit viper envenoming. Hence, there is an urgent need to search for effective antivenom. In this paper, we examined the ability of Calloselasma rhodostoma (Malayan pit viper) monovalent antivenom and the Hemato polyvalent antivenom (both produced by Thai Red Cross Society, TRCS) to neutralize the lethality and toxic effects of H. hypnale venom, as C. rhodostoma is considered a sister taxon of H. hypnale. In vitro neutralization studies showed that the Hemato polyvalent antivenom effectively neutralized the lethality of H. hypnale venom (1.52mgvenom/mL antivenom) as well as the hemorrhagic, procoagulant and necrotic activities of the venom. The monovalent C. rhodostoma antivenom could also neutralize the lethality and toxic activities of the venom, but the potency was lower. The Hemato polyvalent antivenom also effectively protected mice from the lethal and local effects of H. hypnale venom in an in vivo rodent model of envenoming. Furthermore, the polyvalent antivenom could also effectively neutralize the venom of Daboia russelii (2.50mgvenom/mL antivenom), another common cause of snake bites in Sri Lanka and South India. These findings suggested that the Hemato polyvalent antivenom may be beneficial in the antivenom treatment of H. hypnale envenoming.
Snakebite has been categorised as a ‘neglected tropical disease’ by WHO
in 2009 and it affects mainly the poorer countries like Africa and Asia. The standard
treatment for snake envenomation is the anti-snake venom medication which can be
very expensive, not readily available and specific against a snake species. This study
was conducted to screen the phytochemical compounds of Tamarindus indica seed
extract (TSE) and its in-vitro effects on snake venom of three snake species; namely
Daboia russelli, Naja kaouthia and Ophiophagus hannah. (Copied from article).
Tropidolaemus wagleri is a species of Asian pitviper with a geographic range including Thailand, Vietnam, Malaysia, Singapore, Bruniei, parts of Indonesia, and the Philippines. Tropidolaemus is a member of the Crotalinae subfamily, within Viperidae. The genus Tropidolaemus includes five species, and was once included within the genus Trimeresurus. While some osteologic characteristics have been noted a comprehensive description of cranial elements has not been produced for T. wagleri. An in-depth description of the cranial skeleton of Tropidolaemus wagleri lays the foundation for future projects to compare and contrast other taxa within Crotalinae and Viperidae. The chosen reference specimen was compared to the presumed younger specimens to note any variation in ontogeny. The study here provides a comprehensive description of isolated cranial elements as well as a description of ontogenetic change within the specimens observed. This study contributes to the knowledge of osteological characters in T. wagleri and provides a foundation for a long term project to identify isolated elements in the fossil record.
This data article is about reptiles (lizard, snake, and skink) captured from fragmented forest within man-made lake of Tasik Kenyir that is situated in Terengganu State, Peninsular Malaysia. Data collection was conducted in January 2019 and sampling methods included drift fenced-pitfall traps and Visual Encounter Survey (VES). All animals were identified, measured snout to vent (SVL) and weighted before their release at the site of capture. The highlights like conservation statuses in the wild, detection type and substrate type are presented with the data to increase its value. A total of 73 individuals from 18 species, 15 generas and seven families of reptiles were recorded. The data comprised of seven reptile family groups Agamidae, Gekkonidae, Scincidae, Colubridae, Elapidae, Viperidae and Homalopsidae. Reptiles like Cyrtodactylus quadrivirgattus (n = 33, 45.2%) and Aphaniotis fusca (n = 7, 9.6%) were most dominant in the checklist and most of the animals were captured using VES. Data of SVL and mass of the animals can be further interpreted by researchers to assess the health condition of animals in the altered habitats.
Daboia siamensis monovalent antivenom (DSMAV, Thailand) exhibited comparable immunoreactivity toward the venoms of eastern Russell's vipers from Thailand and Indonesia. It also effectively neutralized the procoagulant and lethal effects of both venoms, showing high potency. The Indonesian heterologous trivalent antivenom SABU (Serum Anti Bisa Ular), however, has very weak immunoreactivity and it failed to neutralize the Russell's viper venoms. DSMAV appears to be the appropriate choice of antivenom to treat Russell's viper envenoming.
The hump-nosed pit viper, Hypanle hypnale, contributes to snakebite mortality and morbidity in Sri Lanka. Studies showed that the venom is hemotoxic and nephrotoxic, with some biochemical and antigenic properties similar to the venom of Calloselasma rhodostoma (Malayan pit viper). To further characterize the complexity composition of the venom, we investigated the proteome of a pooled venom sample from >10 Sri Lankan H. hypnale with reverse-phase high performance liquid chromatography (rp-HPLC), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and peptide sequencing (tandem mass-spectrometry and/or N-terminal sequencing). The findings ascertained that two phospholipase A2 subtypes (E6-PLA2, W6-PLA2) dominate the toxin composition by 40.1%, followed by snake venom metalloproteases (36.9%), l-amino acid oxidase (11.9%), C-type lectins (5.5%), serine proteases (3.3%) and others (2.3%). The presence of the major toxins correlates with the venom's major pathogenic effects, indicating these to be the principal target toxins for antivenom neutralization. This study supports the previous finding of PLA2 dominance in the venom but diverges from the view that H. hypnale venom has low expression of large enzymatic toxins. The knowledge of the composition and abundance of toxins is essential to elucidate the pathophysiology of H. hypnale envenomation and to optimize antivenom formulation in the future.
Envenomation by hump-nosed pit viper (Hypnale hypnale, Hh) in Sri Lanka has caused significant morbidity and mortality, attributed to 35% of total venomous snakebites. In Southwestern India (Kerala), H. hypnale was increasingly identified as a dangerous and common source of envenomation, second to the Russell's viper but ahead of the cobra bites. Unfortunately, there is still no specific antivenom to date. This study aims to investigate the immunological properties of the venom and to assess the feasibility of specific Hh antivenom production as well as the development of a diagnostic assay. Hh venom elicited satisfactory titers of anti-Hh IgG in rabbits after 3rd immunization. The anti-Hh IgG, isolated with caprylic acid precipitation method, was effective in neutralizing the venom lethality (potency=48 LD(50) per ml IgG) as well as its procoagulant, hemorrhagic and necrotic effects, indicating the possibility to produce the specific antivenom using the common immunization regime. Cross-reactivity studies using indirect ELISA showed that anti-Hh IgG cross-reacted extensively with several Asiatic crotalid venoms, particularly that of Calloselasma rhodostoma (73.6%), presumably due to the presence of venom antigens common to both snakes. Levels of immunological cross-reactivity were vastly reduced with double-sandwich ELISA. Further work demonstrated that the assay was able to distinguish and quantify venoms of H. hypnale, Daboia russelii and Echis carinatus sinhaleyus (three common local viperid) used to spike human sera at various concentrations. The assay hence may be a useful investigating tool for diagnosing biting species and studying the time course profile of venom concentrations in blood.
Here we report for the first time that L-amino acid oxidase (LAAO), a major component of snake venom, induces apoptosis in yeast. The causative agent for induction of apoptosis has been shown to be hydrogen peroxide, produced by the enzymatic activity of LAAO. However, the addition of catalase, a specific hydrogen peroxide scavenger, does not prevent cell demise completely. Intriguingly, depletion of leucine from the medium by LAAO and the interaction of LAAO with yeast cells are shown to be the major factors responsible for cell demise in the presence of catalase.
A thrombin-like enzyme (termed albolabrase) was isolated in purified form from the venom of Cryptelytrops albolabris (white-lipped tree viper) using high performance anion ion exchange and gel filtration chromatography. The molecular mass of albolabrase was 33.7 kDa as determined by SDS-PAGE and 35.8 kDa as determined by Superose gel filtration chromatography. The N-terminal sequence was determined to be VVGGDECNINE which is homologous to many snake venom thrombin-like enzymes. Albolabrase exhibits both arginine ester hydrolase and arginine amidase activities and the enzyme is fastidious towards tripeptide chromogenic anilide substrates. The fibrinogen clotting activity was optimum at 3mg/mL bovine fibrinogen, and showed distinct species differences in the following decreasing order: bovine fibrinogen>dog fibrinogen≈human fibrinogen>goat fibrinogen. The enzyme failed to clot both rabbit and cat fibrinogens. Reversed-phase HPLC analysis on the breakdown products of fibrinogenolytic action of albolabrase indicated that the enzyme belongs to the AB class of snake venom thrombin-like enzyme. In the indirect ELISA, IgG anti-albolabrase reacted extensively with most crotalid venoms, except with Tropidolaemus wagleri and Calloselasma rhodostoma venoms. The double sandwich ELISA, however, showed that anti-albolabrase reacted strongly only with venoms from the Trimeresurus complex, and that the results support the proposed new taxonomy changes concerning the Trimeresurus complex.
The L-amino acid oxidase of Malayan pit viper (Calloselasma rhodostoma) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 132,000 as determined by Sephadex G-200 gel filtration chromatography and 66,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is a glycoprotein, has an isoelectric point of 4.4, and contains 2 mol of flavin mononucleotide per mole of enzyme. The N-terminal amino acid sequence of the enzyme was A-D-D-R-N-P-L-A-E-E-F-Q-E-N-N-Y-E-E-F-L. Kinetic studies suggest the presence of a alkyl side-chain binding site in the enzyme and that the binding site comprises at least four hydrophobic subsites. The characteristics of the binding site differ slightly from those of cobra venom L-amino acid oxidases.
The knowledge of venom pharmacokinetics is essential to improve the understanding of envenomation pathophysiology. Using a double-sandwich ELISA, this study investigated the pharmacokinetics of the venom of hump-nosed pit viper (Hypnale hypnale) following intravenous and intramuscular injections into rabbits. The pharmacokinetics of the venom injected intravenously fitted a three-compartment model. There is a rapid (t1/2π = 0.4 h) and a slow (t1/2α = 0.8 h) distribution phase, followed by a long elimination phase (t1/2β = 19.3 h) with a systemic clearance of 6.8 mL h(-1) kg(-1), consistent with the prolonged abnormal hemostasis reported in H. hypnale envenomation. On intramuscular route, multiple peak concentrations observed in the beginning implied a more complex venom absorption and/or distribution pattern. The terminal half-life, volume of distribution by area and systemic clearance of the venom injected intramuscularly were nevertheless not significantly different (p > 0.05) from that of the venom injected intravenously. The intramuscular bioavailability was exceptionally low (Fi.m. = 4%), accountable for the highly varied median lethal doses between intravenous and intramuscular envenomations in animals. The findings indicate that the intramuscular route of administration does not significantly alter the pharmacokinetics of H. hypnale venom although it significantly reduces the systemic bioavailability of the venom.
We report a case of a 70-year-old farmer admitted for viper bite who presented with bilateral hyphema and angle closure attack. He was managed conservatively with topical steroids and cycloplegics. He responded well and was discharged after 2 weeks.
Indirect ELISA shows that the antibodies to Calloselasma rhodostoma venom hemorrhagin (CR-HMG), thrombin-like enzyme (CR-TLE) and L-amino acid oxidase (CR-LAAO) exhibited strong to moderate cross-reactions with most crotalid and viperid venoms, but only anti-CR-LAAO cross-reacted with the elapid venoms. However, the indirect ELISA failed to detect some antigenic similarities demonstrable by cross-neutralization study. The double-sandwich ELISA for the three anti-C. rhodostoma venom components exhibited a much lower level of cross-reactions than the indirect ELISA.
A thrombin-like enzyme, purpurase, was purified from the Cryptelytrops purpureomaculatus (mangrove pit viper) venom using high performance ion-exchange and gel filtration chromatography. The purified sample (termed purpurase) yielded a homogeneous band in SDS-polyacrylamide gel electrophoresis with a molecular weight of 35,000. The N-terminal sequence of purpurase was determined to be VVGGDECNINDHRSLVRIF and is homologous to many other venom thrombin-like enzymes. Purpurase exhibits both arginine ester hydrolase and amidase activities. Kinetic studies using tripeptide chromogenic anilide substrates showed that purpurase is not fastidious towards its substrate. The clotting times of fibrinogen by purpurase were concentration dependent, with optimum clotting activity at 3mg fibronogen/mL. The clotting activity by purpurase was in the following decreasing order: cat fibrinogen>human fibrinogen>dog fibrinogen>goat fibrinogen>rabbit fibrinogen. Reversed-phase HPLC analysis of the products of action of purpurase on bovine fibrinogen showed that only fibrinopeptide A was released. Indirect ELISA studies showed that anti-purpurase cross-reacted strongly with venoms of most crotalid venoms, indicating the snake venom thrombin-like enzymes generally possess similar epitopes. In the more specific double-sandwich ELISA, however, anti-purpurase cross-reacted only with venoms of certain species of the Trimeresurus complex, and the results support the recent proposed taxonomy changes concerning the Trimeresurus complex.