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At least 487 records · Page 27Linked to original sources
PubMedDate not supplied

Bites by Russell's vipers (Daboia russelii siamensis) in Myanmar: effect of the snake's length and recent feeding on venom antigenaemia and severity of envenoming.

An improved enzyme immunoassay technique (EIA) was used in the diagnosis of 311 suspected Russell's viper bite cases in Myanmar [Burma], 181 of whom (58%) had systemic envenoming. Russell's viper venom was detected in the sera of 175 (56.3%), cobra or green pit viper venoms in 4 (1.3%), and no venom in the remaining 132 (42.4). Among 175 of these patients who failed to bring the dead snake, EIA achieved a specific diagnosis of Russell's viper envenoming in 101 (58%). The serum venom antigen concentration was higher in patients with systemic envenoming than in those with local or no envenoming and it increased with the development of coagulopathy. Stomach contents were examined in 101 Russell's vipers responsible for bites. The presence of prey, usually a rodent, in the snake's stomach, indicating that it had eaten recently, did not influence the severity of envenoming, the initial venom level, or the percentage circumference increase and the extent of local swelling in the bitten limb. One hundred and fifty-five Russell's vipers responsible for bites showed a bimodal distribution of total lengths. The smaller snakes had probably been born that year. Longer snakes were responsible for more severe envenoming, a shorter interval between the bite and the detection of incoagulable blood, and more extensive local swelling with a greater percentage circumference increase of the bitten limb; but their bites were not associated with higher initial venom antigenaemia or a greater risk of developing acute renal failure.

Adult↗
PubMedDate not supplied

A national hospital-based survey of snakes responsible for bites in Thailand.

Snakes which had been killed and brought to hospital with the patients they had bitten were collected in 80 district and provincial hospitals throughout 67 provinces in Thailand in order to establish the geographical distribution and relative medical importance of the venomous species. Of the 1631 snakes collected, 1145 were venomous: Malayan pit vipers (Calloselasma rhodostoma), green pit vipers (Trimeresurus albolabris) and Russell's vipers (Daboia russelii) were the most numerous, while T. albolabris, C. rhodostoma and spitting cobras ('Naja atra') were the most widely distributed. In 22 cases, non-venomous species were mistaken for venomous ones and antivenom was used unnecessarily. The Malayan krait (Bungarus candidus) was confused with B. fasciatus in 5 cases and B. fasciatus antivenom was used inappropriately. The study extended the known ranges of most of the medically-important venomous species in Thailand. Correct identification of venomous snakes is especially important in Thailand because the locally-produced antivenoms are monospecific. The technique of hospital-based collection, labelling and preservation of dead snakes brought by bitten patients is recommended when rapid assessment of a country's medically important herpetofauna is required.

Animals↗
PubMed1988

Proteolytic, hemorrhagic and hemolytic activities of snake venoms.

Proteolytic, hemorrhagic and hemolytic activities were tested on 47 different venoms from the Crotalidae, Viperidae, Elapidae, and Hydrophiidae families. Antihemorrhagic activity of crude opossum (Didelphis virginiana) and woodrat (Neotoma micropus) serum was tested against the venoms that presented hemorrhagic activity. All venoms showed proteolytic activity when non-specific substrates such as hide powder and collagen were used. Members of the Crotalidae family had the highest hide powder, chymotrypsin-like and hemorrhagic activity. However, members of the Elapidae family had the highest collagen activity. Hemolytic activity was present in 85% of the snake venoms tested. The crude opossum and woodrat serum neutralized the hemorrhagic activity of all the hemorrhagic venoms. Of particular interest is the poor correlation between the venom activities measured here and the phylogenetic position of the snake that possess them. This is particularly true at the genus and species level. Differences in activities were found among individuals of the same genus. The significance of these differences among venoms of closely related snakes is unknown. They do not seem to be adaptive, however little is known of the physiology and habits of most venomous snakes.

Animals↗
PubMed1990

Variation in venom composition and reactivity in two specimens of yellow-faced whip snake (Demansia psammophis) from the same geographical area.

Gel filtration chromatography and SDS-PAGE of venom from two specimens of Demansia psammophis showed little similarity. Amidolytic activity of the venoms, however, was in the same order of reactivity against various chromogenic substrates. The venom from both snakes produced precipitin lines with brown snake antivenom but the venom detection kit (Commonwealth Serum Laboratories) identified one venom as brown snake (Pseudonaja sp.) and the other as tiger snake (Notechis sp.). These results raise questions about the phylogeny of this species.

Animals↗
PubMed1993

Delivery of Duvernoy's secretion into prey by the brown tree snake, Boiga irregularis (Serpentes:Colubridae).

Many colubrid snakes, like the more venomous elapid and viperid snakes, can produce and inject an oral secretion that is toxic and may present a human health risk. However, colubrid oral toxins are produced in a Duvernoy's gland and delivered not through a hollow fang, but instead by long, often grooved teeth under low pressure. The possible role of Duvernoy's secretion in functions other than rapid killing of prey make it important to know how and where this secretion is delivered during a feeding strike. We used ELISA analysis to determine the quantity and proportional distribution of Duvernoy's secretion delivered into the integument compared to the viscera during a feeding strike by the colubrid snake Boiga irregularis. We determined that only about 54% (1-5 mg) of the secretion actually reached the viscera and that the rest remained in the integument. The amount reaching the viscera is about three to eight times the i.p. LD50 for mice, but these snakes depend more on constriction than toxins to kill their prey. Consequently, delivery of Duvernoy's secretion by B. irregularis is hypothesized to be part of a digestive function and its toxic properties a byproduct of this role.

Animals↗
PubMed1992

A comparative study on the electrophoretic patterns of snake venoms.

1. Examination of the polyacrylamide gel electrophoretic (PAGE) and SDS-PAGE patterns of snake venoms shows that these patterns are useful for species differentiation (and hence identification) for snakes of certain genera but have only limited application for snakes from some other genera, due either to the marked individual variations in the venoms or the lack of marked interspecific differences within the same genus. 2. There is no substantial intersubspecific difference in the electrophoretic patterns of the venoms. 3. In general there are no common characteristics in the electrophoretic patterns of the venom at the generic level because of the wide variations in the electrophoretic patterns of venoms of snakes within the same genus. 4. At the familial level, the venoms of Elapidae exhibited SDS-PAGE patterns distinct from those of Crotalidae.

Animals↗
PubMed2005

Snake venom C-type lectins interacting with platelet receptors. Structure-function relationships and effects on haemostasis.

Snake venoms contain components that affect the prey either by neurotoxic or haemorrhagic effects. The latter category affect haemostasis either by inhibiting or activating platelets or coagulation factors. They fall into several types based upon structure and mode of action. A major class is the snake C-type lectins or C-type lectin-like family which shows a typical folding like that in classic C-type lectins such as the selectins and mannose-binding proteins. Those in snake venoms are mostly based on a heterodimeric structure with two subunits alpha and beta, which are often oligomerized to form larger molecules. Simple heterodimeric members of this family have been shown to inhibit platelet functions by binding to GPIb but others activate platelets via the same receptor. Some that act via GPIb do so by inducing von Willebrand factor to bind to it. Another series of snake C-type lectins activate platelets by binding to GPVI while yet another series uses the integrin alpha(2)beta(1) to affect platelet function. The structure of more and more of these C-type lectins have now been, and are being, determined, often together with their ligands, casting light on binding sites and mechanisms. In addition, it is relatively easy to model the structure of the C-type lectins if the primary structure is known. These studies have shown that these proteins are quite a complex group, often with more than one platelet receptor as ligand and although superficially some appear to act as inhibitors, in fact most function by inducing thrombocytopenia by various routes. The relationship between structure and function in this group of venom proteins will be discussed.

Amino Acid Sequence↗
PubMed1987

Present tests for detection of snake venom: clinical applications.

Immunologic tests for detection of snake venom and venom antibodies have important clinical applications. Enzyme-linked immunoassay (ELISA) and radioimmunoassay (RIA) provide adequate specificity and sensitivity. The former is much more widely used because it is inexpensive, relatively easy to perform, and uses stable reagents. Some ELISA systems will detect 0.5 ng of venom; however, a sensitivity of 10 to 100 ng is more usual. Minimum running time is 30 to 45 minutes; with longer times, greater sensitivity can be attained. Wound aspirate, serum, and urine are the most suitable materials for venom detection. ELISA has been used for clinical diagnosis of snakebite, to monitor antivenom dose, to study clinical syndromes associated with envenomation, to detect venom in forensic cases, and to evaluate first aid techniques. The indirect ELISA usually is used for detecting and titrating venom antibody. This is potentially useful in epidemiological studies of snakebite incidence, in evaluating potency and paraspecific activity of antivenoms, and in studying response to venom immunogens. Current ELISA systems involving snake venoms have low specificity, and most cannot reliably differentiate venoms of related snakes. Venom antibody detection assays are less satisfactory than those for venom; nonspecific reactions and cross-reactivity are unacceptably high. Methods for improvement of snake venom immunodiagnosis are discussed.

Antibodies↗
PubMedDate not supplied

Five years of snake envenoming in far north Queensland.

OBJECTIVE: To describe the epidemiology, clinical features, treatment and outcomes of patients with elapid snake envenoming in far north Queensland. METHODS: Review of patients admitted with snake envenoming to Cairns Base Hospital, Queensland, from 1 January 1996-31 December 2000. RESULTS: A total of 264 patients presented to the hospital with a diagnosis of snakebite. Of these, 27 (10%) had clinical evidence of envenoming, including seven children. All envenomed patients had been bitten on a limb. Two patients had correct initial first aid applied. Commercially available venom detection kits were used in 23 patients; 14 (61%) bite site swabs were positive, but only four (23%) of 17 urine Venom Detection Kits were positive. Antivenom was administered to 20 envenomed patients. The five brown snake envenomed patients required a median of 9 ampoules of antivenom to treat their coagulopathy. Sixteen patients were admitted to the ICU, with six requiring ventilation. Six patients were successfully managed in the ED observation ward. Three patients envenomed by a taipan, and one by a death adder were discharged with ongoing neurological symptoms. There was one death from brown snake envenoming. CONCLUSIONS: The incidence of snakebite and envenoming in far north Queensland is higher than reported from hospitals in capital cities and is a significant health issue.

Adolescent↗
PubMed2003

Snake venom vascular endothelial growth factors (VEGFs) exhibit potent activity through their specific recognition of KDR (VEGF receptor 2).

Vascular endothelial growth factor (VEGF165) exhibits multiple effects via the activation of two distinct endothelial receptor tyrosine kinases: Flt-1 (fms-like tyrosine kinase-1) and KDR (kinase insert domain-containing receptor). KDR shows strong ligand-dependent tyrosine phosphorylation in comparison with Flt-1 and mainly mediates the mitogenic, angiogenic, and permeability-enhancing effects of VEGF165. Here we show the isolation of two VEGFs from viper venoms and the characterization of their unique biological properties. Snake venom VEGFs strongly stimulated proliferation of vascular endothelial cells in vitro. Interestingly, the maximum activities were almost twice that of VEGF165. They also induced strong hypotension on rat arterial blood pressure compared with VEGF165 in vivo. A receptor binding assay revealed that snake venom VEGFs bound to KDR-IgG with high affinity (Kd = approximately 0.1 nm) as well as to VEGF165 but did not interact with Flt-1, Flt-4, or neuropilin-1 at all. Our data clearly indicate that snake venom VEGFs act through the specific activation of KDR and show potent effects. Snake venom VEGFs are a highly specific ligand to KDR and form a new group of the VEGF family.

Amino Acid Sequence↗
PubMed1981

Acute renal failure in children following snake bite.

Snake venom poisoning accounted for 1.4% of 4360 infants and children admitted to a south Indian hospital during the years 1976-1979 and was the commonest cause of acute renal failure encountered. Most of the 42 children with anuria following snake bite had evidence of intravascular coagulation and acute tubular necrosis. Russell's viper was the only snake recognized in all the cases of anuria in which species identification was possible. Renal failure complicating snake bite was relatively more frequent and more severe in children than in adults.

Acute Kidney Injury↗
PubMed2000

Morbidity after a bite from a 'non-venomous' pet snake.

We report the first recorded case of morbidity from the bite of a red-neck keelback snake (Rhabdophis subminiatus) from South East Asia. This is a species of the Colubrid family which originated from South East Asia. Severe envenomation from this snake was reported as poisonous in the West as far back as 1978 but it is still being classified as non-venomous. This classification led our patient to keep this 'harmless' snake as a pet. We recommend that this snake be reclassified as 'venomous' or at least warnings be issued to the public not to keep it as a pet.

Adult↗
PubMed2002

[Snake bites and antivenom availability in the urban community of Niamey, Niger].

In order to appreciate certain aspects of the epidemiology of snake bites and the availability of antivenom in Niamey (the capital of Niger), we performed a series of retrospective and prospective studies. The retrospective study involved 175 snake bite patients hospitalised from 1 January 1997 to 31 December 1999 in the internal medicine and surgery wards of the two national hospitals of Niamey. The average age of patients was 29 years, with 3 years and 80 years as limits. The average number of snake bites was 58 cases per year with an annual incidence of approximately 10 cases for 100,000 inhabitants. Males were mainly concerned with a sex-ratio of 2.4 (124 males versus 51 females). Snake bites involved mostly teenagers (29.1%). 84.6% of bites occurred in persons aged 15 to 60 years. Incidence was higher during the farming period: 65% of cases occurred between June and October. Lethality reached 6.9%. However, 25.7% of the patients left hospital without staff permission before the end of the treatment. Complications represented 4.6% of the cases and consisted in necrosis, gangrene and coagulopathy. The treatment protocol was inconsistent, such that both therapeutic algorithm and formation are necessary. The prospective survey involved 41 pharmacies or drug middlemen and hospital drug stocks, prospected from 1 January to 31 May 2000. Antivenom was available in 1 hospital and 1 pharmacy and stocks could be considered sufficient for 1 year. However, it appeared that the supply policy had not been clearly defined.

Adolescent↗
PubMed1989

[Pulmonary embolism and disseminated intravascular coagulation after being bitten by a Bothrops lanceolatus snake. Apropos of a case].

The authors report the case of a Bothrops lanceolatus snake bite complicated by severe pulmonary embolism a few hours after admission. This thromboembolic complication developed despite heparin therapy and was followed by disseminated intravascular coagulation (DIC). Vascular thrombosis and pulmonary embolism are rare after Bothrops lanceolatus snake bite as patients are usually hypocoagulable due to DIC. In this case, the thromboembolism was probably caused by the procoagulant effect of the thrombin-like enzymes of the snake venom which may have been injected directly into the vein of a young woman taking a contraceptive pill. A specific antivenin which has recently become available fort treatment may decrease the complications of Bothrops lanceolatus snake bite.

Adult↗
PubMed1977

Three instructive cases of tiger snake (Notechis scutatus) envenomation--and how a radioimmunoassay proved the diagnosis.

Three unusual cases are described, in which, in separate incidents, young snake bite victims were found comatose. Tiger snake vemon was detected by radioimmunoassay in the urine and serum, and in one case on the clothing of these children. Gross myoglobinuria was present in all cases. The three cases demonstrate clearly the myolytic potential of tiger snake venom if specific treatment (administration of antivenom) is delayed. Extreme elevation of serum enzyme levels was found in the two victims who survived. Evidence was obtained that the major neurotoxin of tiger snake venom is absorbed at least partly via the lymphatics and that some is excreted in the urine.

Acute Kidney Injury↗
PubMed1998

[Clinical picture and treatment of venomous snake bites in Yugoslavia].

Snakes of the Balkan peninsula represent an important part of the fauna of this part of Europe. Due to its biochemical complexity, snake venom cannot be compared with venoms of any other venomous animals. The primary effect of venoms of snakes of this region (Viperina) is local (myonecrosis and hemorrhage) and hemotoxic. Following the bite local signs occur very soon: pain, edema, erythema, signs of hemolysis as well as systemic: nausea, vomiting, hemorrhages in vital organs, sweating, prostration. Systemic manifestations following viperine bite, edema and hemorrhagic complications mostly disappear within a week, while coagulation disorders may persist for two or three weeks. The management of snake bites starts with application of a specific antitoxin, in our country being produced at the Institute of Immunology and Virology TORLAK in Belgrade.

Humans↗
PubMed1978

Psychophysiological responses to presentation of a caged snake among behaviorally avoidant and non-avoidant college students.

Sixty-six coeds who reported fear of snakes on a paper-and-pencil fear inventory were exposed to a Physiological Response Test, during which their electrodermal and cardiac responses to a neutral stimulus and a caged snake were recorded. Half of these coeds then were exposed to a representative Behavioral Avoidance Test, on the basis of which they were classified as avoidant, as non-avoidant, or as neither. Those remaining were classified similarly with an Incentive Behavioral Avoidation Test, before which each was offered an incentive for displaying non-fearfulness. The electrodermal response data showed that students classifed as avoidant had not been more responsive to snake confrontation than the the students classified as non-avoidant. The cardiac response data showed that avoidant Ss had been relatively more responsive to the snake cue, but that differential responsiveness was not robust. These results held for both behavioral avoidance tests.

Animals↗
PubMed1989

Morphology and distribution of neurons in the retina of the American garter snake Thamnophis sirtalis.

It is confirmed that cone photoreceptors observed in flatmounts of the American garter snake Thamnophis sirtalis, retina correspond to the retinal mosaic viewed in the living eye (Land and Snyder, Vision Res. 11:105-114, '85). The garter snake has three major morphological types of cones; large single cones, small single cones, and double cones. The brightly reflecting components seen in the living eye are large single cones and principle cones of double cones, whereas irregularly spaced dark regions within this mosaiac mark the positions of small single cones. The "sparkle" of the retinal mosaic originates from the ellipsoid region of the cones where microdroplets of high refractive index are densely packed. Unlike conventional oil droplets, these microdroplets reside adjacent to mitochondrial cristae within the ellipsoid. However, the microdroplets may function collectively as a single large oil droplet to increase the angular sensitivity of the inner segments, thus reducing a potentially large Stiles-Crawford effect predicted for this geometrically small eye. The ganglion cell layer of the garter snake comprises two morphologically distinct populations of presumed neurons; classical neurons and microneurons. Density distribution maps for neurons in the ganglion cell layer and the photoreceptor layer reveal the presence of a putative area centralis and a horizontal visual streak. The topography of large cones parallels that of classical neurons. Small single cones have a more circular distribution, but also peak in density at the area centralis. The convergence of cones to classical neurons is lowest at the area centralis, 2.5:1, and highest, 4:1, at the retinal edge. With its interesting structural features, the garter snake retina provides helpful insight into different strategies in eye design.

Animals↗