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PubMed1996

Gene rearrangements in snake mitochondrial genomes: highly concerted evolution of control-region-like sequences duplicated and inserted into a tRNA gene cluster.

Mitochondrial DNA (mtDNA) regions corresponding to two major tRNA gene clusters were amplified and sequenced for the Japanese pit viper, himehabu. In one of these clusters, which in most vertebrates characterized to date contains three tightly connected genes for tRNA(Ile), and tRNA(Gln), and tRNA(Met), a sequence of approximately 1.3 kb was found to be inserted between the genes for tRNA(Ile) and tRNA(Gln). The insert consists of a control-region-like sequence possessing some conserved sequence blocks, and short flanking sequences which may be folded into tRNA(Pro), tRNA(Phe), and tRNA(Leu) genes. Several other snakes belonging to different families were also found to possess a control-region-like sequence and tRNA(Leu) gene between the tRNA(Ile)and tRNA(Gln) genes. We also sequenced a region surrounded by genes for cytochrome b and 12S rRNA, where the control region and genes for tRNA(Pro) and tRNA(Phe) are normally located in the mtDNAs of most vertebrates. In this region of three examined snakes, a control-region-like sequence exists that is almost completely identical to the one found between the tRNA(Ile) and tRNA(Gln) genes. The mtDNAs of these snakes thus possess two nearly identical control-region-like sequences which are otherwise divergent to a large extent between the species. These results suggest that the duplicate state of the control-region-like sequences has long persisted in snake mtDNAs, possibly since the original insertion of the control-region-like sequence and tRNA(Leu) gene into the tRNA gene cluster, which occurred in the early stage of the divergence of snakes. It is also suggested that the duplicated control-region-like sequences at two distant locations of mtDNA have evolved concertedly by a mechanism such as frequent gene conversion. The secondary structures of the determined tRNA genes point to the operation of simplification pressure on the T psi C arm of snake mitochondrial tRNAs.

Animals↗
PubMed1995

Higher-level snake phylogeny inferred from mitochondrial DNA sequences of 12S rRNA and 16S rRNA genes.

Portions of two mitochondrial genes (12S and 16S ribosomal RNA) were sequenced to determine the phylogenetic relationships among the major clades of snakes. Thirty-six species, representing nearly all extant families, were examined and compared with sequences of a tuatara and three families of lizards. Snakes were found to constitute a monophyletic group (confidence probability [CP] = 96%), with the scolecophidians (blind snakes) as the most basal lineages (CP = 99%). This finding supports the hypothesis that snakes underwent a subterranean period early in their evolution. Caenophidians (advanced snakes), excluding Acrochordus, were found to be monophyletic (CP = 99%). Among the caenophidians, viperids were monophyletic (CP = 98%) and formed the sister group to the elapids plus colubrids (CP = 94%). Within the viperids, two monophyletic groups were identified: true vipers (CP = 98%) and pit vipers plus Azemiops (CP = 99%). The elapids plus Atractaspis formed a monophyletic clade (CP = 99%). Within the paraphyletic Colubridae, the largely Holarctic Colubrinae was found to be a monophyletic assemblage (CP = 98%), and the Xenodontinae was found to be polyphyletic (CP = 91%). Monophyly of the henophidians (primitive snakes) was neither supported nor rejected because of the weak resolution of relationships among those taxa, except for the clustering of Calabaria with a uropeltid, Rhinophis (CP = 94%).

Animals↗
PubMed1998

Use of snake venom fractions in the coagulation laboratory.

Snake venom toxins are now regularly used in the coagulation laboratory for assaying haemostatic parameters and as coagulation reagents. Snake venom thrombin-like enzymes (SVTLE) are used for fibrinogen and fibrinogen breakdown product assay as well as detecting dysfibrinogenaemias. Significantly, because SVTLE are not inhibited by heparin, they can be used for defibrinating samples that contain the anticoagulant before assay of haemostatic variables. Prothrombin activators are found in many snake venoms and are used in prothrombin assays, for studying dysprothrombinaemias and preparing meizothrombin and non-enzymic prothrombin. Russell's viper (Daboia russelli) venom (RVV) contains a number of compounds useful in the assay of factors V, VII, X, platelet factor 3 and lupus anticoagulants. Activators from the taipan, Australian brown snake and saw-scaled viper have been used to assay lupus anticoagulants. Protein C and activated protein C resistance can be measured by means of RVV and Protac, a fast acting inhibitor from Southern copperhead snake venom and von Willebrand factor can be studied with Botrocetin from Bothrops jararaca venom. Finally, phospholipase A2 enzymes and the disintegrins, a family of Arg-Gly-Asp (RGD)-containing proteins found in snake venoms, show great potential for the study of haemostasis including, notably, platelet glycoprotein receptors GPIIb/IIIa and Ib.

Animals↗
PubMed2004

Molecular evidence for a terrestrial origin of snakes.

Biologists have debated the origin of snakes since the nineteenth century. One hypothesis suggests that snakes are most closely related to terrestrial lizards, and reduced their limbs on land. An alternative hypothesis proposes that snakes are most closely related to Cretaceous marine lizards, such as mosasaurs, and reduced their limbs in water. A presumed close relationship between living monitor lizards, believed to be close relatives of the extinct mosasaurs, and snakes has bolstered the marine origin hypothesis. Here, we show that DNA sequence evidence does not support a close relationship between snakes and monitor lizards, and thus supports a terrestrial origin of snakes.

Animals↗
PubMed1995

Isolation and characterization of paramyxoviruses from snakes and their relationship to avian paramyxoviruses.

Several viruses were isolated from snakes which died during an outbreak of disease in a zoo. The viruses could be cultivated at 28 degrees C on a snake cell line (VH2, ATCC CCL 140). In cell culture they formed syncytia, leading to destruction of the monolayer. The isolates were sensitive to treatment with chloroform but not to growth in the presence of IUDR and revealed haemagglutinating activity with chicken erythrocytes. These results, combined with electron microscopic examination of the infectious supernatant, confirmed the diagnosis of paramyxoviruses (PMV). Haemagglutination inhibition tests with antisera against avian PMV revealed a serological relationship between the snake viruses and the avian PMV serotypes 1 and 7. Tests for thermostability at 56 degrees C showed a marked decrease of the haemagglutination and infectivity titres in contrast to the avian PMV serotype 7. The multiplication of the snake viruses seemed to be restricted to incubation temperatures below 37 degrees C. At 28 degrees C the snake viruses could be cultivated in several cell cultures. Separation of virus proteins using polyacrylamide gel electrophoresis showed differences between the snake isolates and avian PMVs of serotypes 1 and 7.

Animals↗
PubMed2005

Chromatin supraorganization, DNA fragmentation, and cell death in snake erythrocytes.

In nucleate erythrocytes of several vertebrate groups, the frequency and intensity of DNA fragmentation associated with programmed cell death vary considerably. Although hemoglobin efficiency may be related to erythrocyte life span, and hemoglobin types and erythrocyte life spans are assumed to vary in reptiles, no data on DNA fragmentation and chromatin organization as related to cell death exist for snakes. In the present study, chromatin supraorganization, DNA fragmentation, and cell death were investigated in four snake species (Crotalus durissus terrificus, Bothrops jararaca, Bothrops alternatus, and Bothrops neuwiedii), which differ in their geographical distribution and habitats, by using image analysis of Feulgen hydrolysis kinetics, the TUNEL assay, single-cell gel electrophoresis, and transmission electron microscopy. Relatively few circulating erythrocytes were found to be simultaneously committed to cell death, although there was some variation among the snake species. Conspicuous nuclear and cytoplasmic organelles suggestive of metabolic activity were seen ultrastructurally in most snake erythrocytes. The DNA of the snake erythrocyte chromatin was much more resistant to Feulgen acid hydrolysis (DNA depurination and breakdown) than that of young adult bullfrog erythrocytes, which had a high frequency and intensity of DNA fragmentation. Of the species studied, B. neuwiedii and C. d. terrificus showed the greatest resistance to Feulgen acid hydrolysis and to the DNA fragmentation, revealed by the TUNEL assay. Although B. neuwiedii also showed the lowest frequency of cells with more damaged DNA in the single-cell gel electrophoresis assay, C. d. terrificus had the highest frequency of damaged cells, possibly because of the abundance of alkaline-sensitive DNA sites. The results for DNA fragmentation and cell death in erythrocytes of B. jararaca and B. alternatus generally differed from those for C. d. terrificus and B. neuwiedii and may reflect differences in the biology of these species selected under different geographical habitats. The differences in erythrocyte cell biology reported here may be related to hemoglobin variants selected in the mentioned snake species and that would lead the cells to different resistances to unfavorable environmental conditions.

Animals↗
PubMed1984

Effect of bilateral vagotomy on the ventilatory responses of the water snake Nerodia sipedon.

The effects of bilateral vagotomy on pulmonary ventilation, O2 consumption, and heart rate were determined for the water snake, Nerodia sipedon, breathing room air at 15, 25, and 30 degrees C and breathing 5.2% CO2 in air at 25 degrees C. At all body temperatures, vagotomy resulted in a four- to sevenfold increase in tidal volume in snakes breathing room air. At the same time, ventilatory frequency decreased such that pulmonary ventilation was unchanged after vagotomy. Heart rate increased approximately 1.5 times after vagotomy, but O2 uptake was unchanged. The air convection requirement decreased similarly with increasing body temperature in both intact and vagotomized snakes. Arterial pH values were similar to those of intact snakes measured in a previous study and decreased by -0.013 U/degrees C. Since this occurs despite elimination of peripheral chemoreceptor input, it is suggested that the temperature compensation is a centrally controlled process. In intact snakes, breathing CO2 resulted in a fourfold increase in ventilation. Elimination of peripheral receptor input by vagotomy resulted in a loss of this ventilatory response to CO2 breathing. This means that peripheral receptors are required for a response to changes in arterial CO2 partial pressure and pH. Snakes thus differ from turtles and mammals in that central chemoreceptors alone are unable to produce the ventilatory response to inspired CO2.

Animals↗
PubMed2005

Snake C-type lectin-like proteins and platelet receptors.

Snake venoms are complex mixtures of biologically active proteins and peptides. Many affect haemostasis by activating or inhibiting coagulant factors or platelets, or by disrupting endothelium. Snake venom components are classified into various families, such as serine proteases, metalloproteinases, C-type lectin-like proteins, disintegrins and phospholipases. Snake venom C-type lectin-like proteins have a typical fold resembling that in classic C-type lectins such as the selectins and mannose-binding proteins. Many snake venom C-type lectin-like proteins have now been characterized, as heterodimeric structures with alpha and beta subunits that often form large molecules by multimerization. They activate platelets by binding to VWF or specific receptors such as GPIb, alpha2beta1 and GPVI. Simple heterodimeric GPIb-binding molecules mainly inhibit platelet functions, whereas multimeric ones activate platelets. A series of tetrameric snake venom C-type lectin-like proteins activates platelets by binding to GPVI while another series affects platelet function via integrin alpha2beta1. Some act by inducing VWF to bind to GPIb. Many structures of these proteins, often complexed with their ligands, have been determined. Structure-activity studies show that these proteins are quite complex despite similar backbone folding. Snake C-type lectin-like proteins often interact with more than one platelet receptor and have complex mechanisms of action.

Animals↗
PubMed1995

Immunoperoxidase detection of ophidian paramyxovirus in snake lung using a polyclonal antibody.

In a retrospective study of proliferative interstitial pneumonia in viperid and nonviperid snakes, formalin-fixed, paraffin-embedded lungs from 52 snakes were screened for immunohistochemical reactivity to ophidian paramyxovirus. All snakes were from zoological collections that experienced mortalities attributed to paramyxovirus infection. Of the 52 snakes, 47 had pulmonary lesions compatible with ophidian paramyxovirus infection. Histologic changes in affected lungs included hyperplasia and hypertrophy of septal and faveolar epithelial cells, loss of ciliated cells, mixed leukocytic interstitial infiltrates, fibrinonecrotic exudate in the lumen of proximal and distal faveolar compartments, and occasional epithelial syncytial cell formation or intraepithelial eosinophilic intracytoplasmic inclusions. Lungs were immunohistochemically stained for paramyxovirus antigens by utilizing rabbit polyclonal antibodies against a paramyxovirus isolate from a black mamba (Dendroaspis polyepis polyepis). Virus infection in 6 snakes was confirmed by virus isolation from frozen lung tissue. Of the 6 lungs from which paramyxovirus was isolated, 5 lungs stained positively for viral antigens utilizing antisera to the black mamba isolate. Altogether, 36 lungs stained positively for paramyxovirus antigens. There was multifocal to diffuse linear staining of the lumenal surface of faveolar epithelium, and there were multiple foci of granular cytoplasmic staining. Immunohistochemical staining of formalin-fixed lungs from snakes with proliferative interstitial pneumonia was helpful as a routine diagnostic test for substantiating a diagnosis of ophidian paramyxovirus infection.

Animals↗
PubMed1996

Distribution of immunoreactive atrial and brain natriuretic peptides in the heart of the chicken, quail, snake and frog.

The distribution of atrial natriuretic peptide (ANP)- and brain natriuretic peptide (BNP)-granules was examined immunohistochemically and ultrastructurally in the hearts of the chicken, Japanese quail, Japanese rat snake and bull-frog. Moreover, natriuretic peptide (NP)-granules in the cardiocytes were analyzed by ultrastructural morphometry. Immunohistochemically, ANP-immunoreactivity (IR) was not detected in any cardiocytes, but BNP-IR was detectable in most atrial and ventricular cardiocytes of both chicken and quail. In the snake, ANP-IR was seen in most atrial and ventricular cardiocytes, which showed traces and negative in BNP-IR, respectively. Both ANP- and BNP-IR were detected in the atrial and ventricular cardiocytes in the frog. Ultrastructurally, most of NP-granules were found in the perinuclear region in the chicken, quail and snake atrium, but the frog atrial cardiocytes had granules generally dispersing widely in the cell. By ultrastructural morphometry, the number of granules in the atrial cardiocyte was greatest in the frog, followed by the snake, and chicken or quail, in this order. The diameter of granules in the atrial cardiocyte was largest in the snake and reduced via the frog to the chicken or quail. In the ventricular cardiocytes of all species, the number and size of granules were significantly less than that in the atrial ones. These results indicated that the hearts of the chicken and quail contain only BNP, and that there are two different natriuretic peptides, ANP and BNP, in the snake and frog hearts.

Animals↗
PubMed1995

[Epidemiology of accidents due to bites of poisonous snakes: a study of cases attended in 1988].

The attendance given to patients by ta specialized Hospital, in S. Paulo, Brazil, during 1988 is studied. The study is based on the medical records of 322 patients and on questionnaires filled out by author during interviews with 209 patients or their companions. The 322 snake-bites occurred mainly between October and April, in the diurnal period, mainly in the afternoon. Most of patients were adult males, mainly between 10 and 20 years of age. The parts of the body most frequently affected were the feet, hands and legs. The snakes of the genera Bothrops, Crotalus and Micrurus were responsible, respectively, for 306 (95.0%) 14 (4.4%) and 2 (0.6%) of the accidents under study. Among the 160 snakes that were classified at the Herpetological Section of the IB, 152 were Bothrops; 142 B. Jararaca, mostly young reptiles, and 8 were of the genus Crotalus. Of the patients, 90.4% recovered completely, 2.2% presented sequelae, 7.5% were transferred and thus it was impossible to follow them up. Of the 209 persons interviewed, the occupational group most prone to snake bites was agricultural workers, followed by studentes; nearly 60% of the accidents ocurred during work; most of the patients had their inferior extremities unprotected at the moment of the bite. On hundred and sixty patients (76.6%) submitted to some from of treatment before coming to the HVB-IB, the more common being the use of a tourniquet (50.2%), local squeezing in an attempt to remove part of the venom (33.5), application of substances on the site of the snake bite (36.8%) and the ingestion of others (12.9%). Slightly over a quarter of the patients underwent some kind of medical treatment before coming to the HVB-IB, the most common being antissepsis (8.2%), administration of antivenom (6.2%), antihistamines (5.7%) and analgesics (5.3%). The snake was seen before it struch by 187 (89.5%) of the 209 persons interviewed and in most cases it adopted the strike posture just before the first bite.

Adolescent↗
PubMed1995

Electroencephalographic abnormalities in patients with snake bites.

Electroencephalograms (EEGs) were obtained for 26 patients with snake bite to observe the cerebral impact of snake venom. All snakes were identified; 19 (73%) were Russell's vipers, one (4%) was a common cobra, five (19%) were hump-nosed vipers, and one (4%) was a dog-faced fresh water snake. The EEG was abnormal in 25 patients (96%) and these results included all the snake species identified. The EEG abnormalities observed were reduced alpha activity, increased theta/beta activity or sharp waves (grade 1), sharp waves or spikes and slow waves (grade 2), or diffuse delta activity (grade 3). Grade 1 changes occurred in 16 patients (62%), grade 11 in eight patients (31%), and grade 111 in one patient (4%). Thus, grade 2 and 3 changes, which were moderately severe to severe abnormalities, occurred in nine patients (35%). One patient had acute renal failure and two others had mild jaundice and hyponatremia. These three patients had EEG abnormalities that were similar to those observed in the remaining 22 patients. The altered EEG, suggestive of an encephalopathy, appeared within hours of the bite and persisted for several days without clinical neurologic effects. The changes were seen mainly in the temporal lobe. Similar changes occurred in both patients with and without antivenom therapy. It appeared that the EEG abnormalities are a consequence of the effects of venom from the bites of a variety of snakes.

Adolescent↗
PubMed1984

Cross-reactivity of bardick snake venom with death adder antivenom.

A case of a young man who was bitten by a bardick snake (Notechis curtus) and who, apart from marked local swelling, had neither signs of coagulopathy nor neurological symptoms, is reported. The bardick snake venom taken from the site of the bite reacted strongly with the death adder antivenom in the snake venom detection kit, but did not react with the Notechis antivenom. This anomalous reactivity was confirmed when dried bardick snake venom was used. In-vitro observations of the bardick snake venom showed that it had anticoagulant properties similar to those of death adder venom, and was not procoagulant as are the venoms of other snakes of the Notechis genus. The clinical importance of these findings is discussed.

Adolescent↗
PubMed1999

Acetylcholinesterase from snake venom as a model for its nerve and muscle counterpart.

Acetylcholinesterase (AChE) plays a key role in cholinergic transmission. At the neuromuscular junction of vertebrates, for example, it allows a fine temporal control of muscle contraction. The presence of AChE in tissues devoid of cholinergic function is also well known and raises the question of its role. In particular, AChE is abundant in the venoms of Elapid snakes, except mambas. AChE purified from snake venom consists of soluble, hydrophilic monomers. Cloning of cDNA of the AChE from Bungarus fasciatus venom showed that its C-terminal peptide is very different from those of other AChEs. The partial sequence of the Bungarus fasciatus AChE gene shows that this peptide is encoded by a new alternative exon, called S for soluble and snake. It is a short very basic peptide of 15 residues. Analysis of the venom enzyme and in vitro expression experiments showed that the last eight residues are removed in the mature protein. AChEs from snake venoms vary in their sensitivity to peripheral site inhibitors, notably to fasciculins from mamba venoms. While Ophiophagus AChE is as sensitive as Torpedo enzyme (IC50 around 10(-10) M), Naja and Heamacatus AChEs are insensitive to the toxin up to a concentration of 10(-6) M Bungarus AChE has an intermediate IC50 of 10(-8) M. Analysis of its sequence reveals two major differences in the peripheral site region, compared to Torpedo or mammalian AChEs: at position 70 it contains a methionine instead of a tyrosine, and at position 285 it contains a lysine instead of an acidic residue (glutamic or aspartic acid). Modification of these residues by site-directed mutagenesis, and enzymatic analysis of modified recombinant enzymes, confirmed that these two residues are implicated in the properties of the Bungarus AChE peripheral site. The presence of an alternative exon, which generates a soluble form of AChE in venoms, raises interesting evolutionary questions: Does it exist in snakes whose venom does not contain AChE, e.g., mambas? Did this exon pre-exist, for expression in other contexts? Snake venom AChEs offer an exceptional system for analyzing the mechanism of peripheral site inhibition, because of their wide range of activities.

Acetylcholinesterase↗
PubMed1998

Sarcocystis infections among snakes in Israel.

Natural infection with Sarcocystis has been recovered from 11 species of snakes from Israel and the adjacent territories (Cisjordan), infection was most abundant in subadults. Sporocyst dimensions obtained from the different snakes overlapped in size, but even in a same host species formed distinct size cohorts clustering either around 8.5 x 6.5 microns and 11.0 x 8.5 microns or around 11.0 x 8.5 microns and 12 x 10 microns. Sporocyst-size distribution was, however, altered following cross infections or in consecutively emitted feces. The largest cohort size conformed with the sporocyst dimensions of S. murivipera Matuscka, Heydorn, Mehlhorn, Abd-Al-Az, Diesing, Bichler 1987, described from Vipera palaestinae, one of the snake species included in the present study. Among infected snakes were rodent predators but also species feeding on smaller prey (reptiles). Sporocysts from eight of these species including some small-prey feeders, were available for infecting rodents, all, like S. murivipera, developed into sarcocysts in laboratory white mice (Mus musculus), but in none of the inoculated rodents from other genera, or reptiles. Sarcocysts found in free-ranging house mice infected V. palaestinae. Despite of an apparent conspecificity, Sarcocystis from the different snake species demonstrated a pronounced variation in their virulence to mice. Primary wall was identical in all ultrastructurally studied sarcocysts found in both house mice and laboratory mice fed on sporocysts from the diverse snake species.

Animals↗
PubMed2002

A logical starting point for developing priorities for lizard and snake ecotoxicology: a review of available data.

Reptiles, specifically lizards and snakes, usually are excluded from environmental contamination studies and ecological risk assessments. This brief summary of available lizard and snake environmental contaminant data is presented to assist in the development of priorities for lizard and snake ecotoxicology. Most contaminant studies were not conducted recently, list animals found dead or dying after pesticide application, report residue concentrations after pesticide exposure, compare contaminant concentrations in animals from different areas, compare residue concentrations found in different tissues and organs, or compare changes in concentrations over time. The biological significance of the contaminant concentrations is rarely studied. A few recent studies, especially those conducted on modern pesticides, link the contaminant effects with exposure concentrations. Nondestructive sampling techniques for determining organic and inorganic contaminant concentrations in lizards and snakes recently have been developed. Studies that relate exposure, concentration, and effects of all types of environmental contaminants on lizards and snakes are needed. Because most lizards eat insects, studies on the exposure, effects, and accumulation of insecticides in lizards, and their predators, should be a top priority. Because all snakes are upper-trophic-level carnivores, studies on the accumulation and effects of contaminants that are known to bioaccumulate or biomagnify up the food chain should be the top priority.

Animals↗
PubMed2001

[Identification of Chinese crude drug snake gallbladder by DNA molecular marker].

AIM: It is difficult to identify the Chinese crude drug snake gallbladder accurately by morphological and microscopical characteristics or chemical components only. In order to solve the problem, the technique based on DNA molecular marker was introduced into the authentication of snake gallbladder. METHODS: DNA templates were extracted from the membrane or the bile of snake gallbladder, and also from the muscle of the original animal Elaphe schrenckii. About 400 bp DNA fragments of 12S rRNA gene were amplified from the templates and sequenced subsequently. RESULTS: Enough amounts of DNA templates could be extracted from a bit of membrane or bile of snake gallbladder. The sequence of amplicons from the membrane, bile and muscle of the same individual were identical completely. CONCLUSION: The technique of DNA molecular marker could be used for the authentication of snake gallbladder and bile. The results indicate that the technique could be used for the identification of crude drugs from other animal secretion. DNA sequence analysis also demonstrated that the origins of commercial snake gallbladder were complicated and more efficient quality control was necessary for supervising the crude drug in the market.

Animals↗
PubMed1992

1991 Sir Henry Wellcome Medal and Prize recipient. Medical studies of the poisonous land and sea snakes found in and around Saudi Arabia.

Studies were carried out to determine the comparative toxicity and pathophysiology of 13 of the more poisonous snakes indigenous to Saudi Arabia. Included were four snakes from the Viperidae family, six from the Elapidae family, and three representative sea snakes from the family Hydrophidae. Anesthetized adult beagle dogs and anesthetized monkeys were used in the study. Vital physiological functions were continuously recorded as were changes in the blood coagulation system and any tissue damage produced by the venom at the site of envenomation. For the intravenous administration of the venom, lyophilized venom was obtained by "milking" each of the live specimens used in the study. Actual envenomation was accomplished by grasping the poisonous reptile and allowing the snake to strike the shaved exposed gluteal muscle of the anesthetized animal. Venom from the snakes of the family Viperidae produced death in an average of 3 hours. The average lethal dose was 1.13 mg/kg. Depression of first and second stage clotting factors was observed with these venoms as well as a decrease in fibrinogen levels and in platelet counts. Findings suggestive of intravascular coagulation were also observed with moderate hemolysis of the formed elements. Some local hemorrhage was seen at the site of envenomation. Venom from the Elapidae family of snakes produced death at an average of 1.7 hours. The average lethal dose was 0.70 mg/kg. Death appeared to be primarily due to respiratory paralysis following blockade at the neuromuscular junction. Only moderate hemolysis was seen with these venoms. No intravascular coagulation or tissue damage was seen. The venom of the family Hydrophidae consistently produced death in less than 30 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗