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The rates at which venomous animals produce venoms are of obvious biological and medical importance, but factors influencing those rates remain poorly understood. We gathered data on venom yield (wet mass of venom) and percentage solids (dry mass of the venom divided by wet mass) for 53 eastern brownsnakes (Pseudonaja textilis) and 36 mainland tigersnakes (Notechis scutatus) over a 4-year period at Venom Supplies Pty. Ltd, a commercial venom production facility in South Australia. Tigersnakes yielded about threefold more venom (by wet mass) than brownsnakes, but with slightly lower percentage solids. Both species showed significant geographic variation in percentage solids. Venom yields varied as a function of the snake's sex and geographic origin, but these effects were secondary consequences of geographic and sex-based differences in body size. Relative head size affected venom yield in brownsnakes but not tigersnakes. Overall, the amount of venom that a snake produced during milking was affected by its species, its geographic origin, its body size and relative head size, and by the time of year that it was milked, as well as by interactions among these factors. Body size was the most important effect on venom yield, with yields increasing more rapidly with size in brownsnakes than in tigersnakes. Research at the intersection of snake ecology and venom characteristics has great potential, but will require a genuinely interdisciplinary approach., (Copyright 2002 Elsevier Science Ltd.)

An Australian common brown snake, Pseudonaja textilis, is known to contain highly lethal neurotoxins. Among them, a long-chain alpha-neurotoxin, pseudonajatoxin b, has been identified. In this report, while presenting evidence for the presence of at least four such long-chain alpha-neurotoxins in the venom of P. textilis, we describe the characteristics of both the mRNA and the gene responsible for the synthesis of these neurotoxins. A precursor toxin synthesized from the gene has been identified as being capable of producing the isoforms possibly by post-translational modifications at its C-terminal end. Recombinant toxins corresponding to the precursor and its product have been found to possess similar binding affinities for muscular acetylcholine receptors (IC(50)=3x10(-8) M) and a lethality, LD(50), of 0.15 microg/g in mice.

Objective: To determine the extent of the snake bite problem in domestic animals, its regional significance and the effects of antivenom treatment., Design: A questionnaire was designed seeking information on the number and type of domestic animals referred, whether treated or untreated, type of snakes and management of the bite., Procedure: The survey form was sent to 10% of veterinary surgeons, selected at random throughout Australia., Results: The response of 106 veterinary surgeons revealed that snake bite in domestic animals is frequent, with an estimated 6200 cases reported annually. Bites were more prominent in rural (78%) than urban areas (22%) with brown, tiger and black snakes accounting for 76%, 113% and 6% of cases, respectively. Cats and dogs were the most frequently reported victims. Ninety-one percent of cats and 75% of dogs survived following the administration of antivenom whereas 66% of cats and 31% of dogs survived without antivenom. Overall, in 33% of cases antivenom was not used, and venom detection kits were used in only 1% of cases. A number of drugs were used in various combinations with or without antivenom and intravenous fluids in the treatment of animals with snake bite, but their role in reducing the severity of envenomations was not assessed., Clinical Implications: Antivenom significantly improves the chances of survival of domestic animals bitten by snakes.

The amino acid sequence of a previously undescribed toxin from Australian death adder venom (Acanthophis antarcticus) has been elucidated. It appears to exist in two forms which are separated by reverse-phase high-performance liquid chromatography, but which have the same sequence and mol. wt. It has 79 amino acid residues and is therefore longer than other long postsynaptic neurotoxins. It shows homology with the conserved regions of the other long postsynaptic neurotoxins except for three unique substitutions of conserved residues, which are Arg-29 instead of Trp or Phe, Leu-33 instead of Arg and Thr-43 instead of Ala.

The procoagulant was isolated from the venom of four clinically significant species of brown snake; Pseudonaja affinis, P. inframacula, P. nuchalis, and P. textilis. HPLC elution profiles and PAGE showed a high degree of homology between the procoagulants from the four species. Antiserum from the CSL Ltd (Brown Snake Antivenom) produced a single band against all four procoagulants. The specific activity of the procoagulant varied between species, while inhibitory studies indicated that the procoagulants were serine proteases with a sialic acid component which also contributes to the coagulant action.

A case of envenomation by a three-week-old inland taipan (Oxyuranus microlepidotus)-the second recorded case of a bite by possibly the most venomous snake in the world - is reported. Evidence which supports the use of the term "inland taipan", and confirms the effectiveness of taipan antivenom in the treatment of bites by this snake, is presented.