Boomslang Venom Research Articles

Factor X activating Atractaspis snake venoms and the relative coagulotoxicity neutralising efficacy of African antivenoms

Atractaspis snake species are enigmatic in their natural history, and venom effects are correspondingly poorly described. Clinical reports are scarce but bites have been described as causing severe hypertension, profound local tissue damage leading to amputation, and deaths are on record. Clinical descriptions have largely concentrated upon tissue effects, and research efforts have focused upon the blood-pressure affecting sarafotoxins. However, coagulation disturbances suggestive of procoagulant functions have been reported in some clinical cases, yet this aspect has been uninvestigated. We used a suite of assays to investigate the coagulotoxic effects of venoms from six different Atractaspis specimens from central Africa. The procoagulant function of factor X activation was revealed, as was the pseudo-procoagulant function of direct cleavage of fibrinogen into weak clots. The relative neutralization efficacy of South African Antivenom Producer’s antivenoms on Atractaspis venoms was boomslang>>>polyvalent>saw-scaled viper. While the boomslang antivenom was the most effective on Atractaspis venoms, the ability to neutralize the most potent Atractaspis species in this study was up to 4–6 times less effective than boomslang antivenom neutralizes boomslang venom. Therefore, while these results suggest cross-reactivity of boomslang antivenom with the unexpectedly potent coagulotoxic effects of Atractaspis venoms, a considerable amount of this rare antivenom may be needed. This report thus reveals potent venom actions upon blood coagulation that may lead to severe clinical effects with limited management strategies.

What killed Karl Patterson Schmidt? Combined venom gland transcriptomic, venomic and antivenomic analysis of the South African green tree snake (the boomslang), Dispholidus typus

BackgroundNon-front-fanged colubroid snakes comprise about two-thirds of extant ophidian species. The medical significance of the majority of these snakes is unknown, but at least five species have caused life-threatening or fatal human envenomings. However, the venoms of only a small number of species have been explored. MethodsA combined venomic and venom gland transcriptomic approach was employed to characterise of venom of Dispholidus typus (boomslang), the snake that caused the tragic death of Professor Karl Patterson Schmidt. The ability of CroFab™ antivenom to immunocapture boomslang venom proteins was investigated using antivenomics. ResultsTranscriptomic-assisted proteomic analysis identified venom proteins belonging to seven protein families: three-finger toxin (3FTx); phospholipase A2 (PLA2); cysteine-rich secretory proteins (CRISP); snake venom (SV) serine proteinase (SP); C-type lectin-like (CTL); SV metalloproteinases (SVMPs); and disintegrin-like/cysteine-rich (DC) proteolytic fragments. CroFab™ antivenom efficiently immunodepleted some boomslang SVMPs. ConclusionsThe present work is the first to address the overall proteomic profile of D. typus venom. This study allowed us to correlate the toxin composition with the toxic activities of the venom. The antivenomic analysis suggested that the antivenom available at the time of the unfortunate accident could have exhibited at least some immunoreactivity against the boomslang SVMPs responsible for the disseminated intravascular coagulation syndrome that caused K.P. Schmidt's fatal outcome. General significanceThis study may stimulate further research on other non-front-fanged colubroid snake venoms capable of causing life-threatening envenomings to humans, which in turn should contribute to prevent fatal human accidents, such as that unfortunately suffered by K.P. Schmidt.

Mass spectrophotometric evidence for P-III/P-IV metalloproteinases in the venom of the Boomslang ( Dispholidus typus)

The Boomslang, Dispholidus typus, is a mid- to rear-fanged arboreal colubrid widely distributed throughout much of the African continent. Envenoming by this species is rare although deaths have been recorded. Typical symptoms associated with envenoming include diffuse intravascular coagulation (DIC) caused by fibrinogen consumption and consequent incoagulable blood together with haemorrhage into tissues such as muscle and brain; together, these procoagulant and haemorrhagic effects of the venom result in a very poor prognosis in patients who receive a large dose of venom and who are not treated with antivenom. Renal failure may also result from acute tubular necrosis resulting from pigment nephropathy. Little is known about the toxic components present in the venom; however, proteolytic activity has been reported although the proteinases involved have not been identified. In this study we provide LC/MS/MS (liquid chromatography/mass spectrometry/mass spectrometry) data supporting the presence of class P-III/P-IV snake venom metalloproteinases (SVMPs) in Boomslang venom. Using a polyclonal antibody raised against the P-III haemorrhagic toxin (Jararhagin) obtained from the venom of the Brazilian pit viper, Bothrops jararaca, we identified by western blot a 65 kDa protein from Boomslang venom which cross-reacted with the jararhagin antibody. A corresponding band from SDS-PAGE was subjected to tryptic digestion followed by LC/MS/MS sequence analysis of the digestion mixture. A variety of peptide sequences were identified in the digest, one of which was clearly homologous with a highly conserved region of the disintegrin-like domains of P-III/P-IV SVMPs. These data provide the first structural evidence for the presence of SVMPs in Boomslang venom; it is possible that SVMPs may also be present in the venoms of other colubrids, which cause similar symptoms in envenomed humans. In other snake venoms, most notably those of the Viperinae and Crotalinae subfamilies, many of the coagulopathic and haemorrhagic syndromes associated with systemic and local envenoming are attributed to SVMPs. The identification of a P-III/P-IV SVMP sequence in D. typus venom suggests that many of the pathological signs resulting from envenoming by this species may also be due to the presence of SVMPs in the venom. It is hoped that these results may accelerate research into colubrid venoms and may provide new insights into novel and more efficacious treatments for colubrid envenoming.

Studies on the coagulant effects of boomslang (Dispholidus typus) venom

Summary Evidence based on coagulation and biochemical studies indicated that the coagulant effect of boomslang venom was chiefly due to its ability to activate prothrombin. It was also able to activate prethrombin I, factor X and possibly factor IX as well. Other effects of the venom on the coagulation system seemed to be of little consequence in relation to its major actions. The action of the venom on prothrombin did not require the presence of calcium ions, phospholipid or any other coagulation factors. Furthermore, the venom was able to split the acarboxy form of prothrombin. The venom could, therefore, be used as a reagent for the detection of acarboxy prothrombin in vitamin K deficiency or antagonism.

The Venom of the Boomslang (Dispholidus Typus): In Vivo and in Vitro Studies

SummaryAn account is given of the effects of boomslang venom in man. Evidence was found of a fibrinolytic state apparently secondary to the coagulant action of the venom. These features rapidly responded to the administration of specific antivenom. In vitro studies, using a homogenate of boomslang parotids, confirmed the coagulant properties of the venom and showed them to be of much greater potency than the proteolytic actions.

Dikellorhynchus and Kanazawaichthys: Nominal Fish Genera Interpreted as Based on Prejuveniles of Malacanthus and Antennarius, Respectively

respiratory failure; contributing factors that may have played a part cannot be readily evaluated. It can only be presumed that respiratory failure was due to coagulation in the lungs. The autopsy was not begun oughout the alimentary tract and in other ans. Death may be caused by clots in pulmonary vessels (emboli). Pa ently, until about eighteen hours after death. The proteolytic principle may have produced pos -mortem hemorrhages as well as the relative fluidity of the blood noticed at autopsy. A total lack of experience with boomslang venom is largely to blame for the tragic events of September 25 and 26.

(1) Reptiles of the World: (2) A Monograph of the Frogs of the Family Microhylidae

(1) THIS well-known book has long been recognised as a standard work on reptile life, and the several reprints which have appeared since its first publication in 1910 testify to its wide popularity and usefulness. In the preface of the revised edition, the author once more expresses the hope that the book will be “everywhere in accord with the latest results of the scientific study of the subject”. However, the new edition contains very little new information, and recent herpetological literature is not well covered. Thus, in treating of the Opisthoglyph snakes, the author speaks of “the absence of records to show what their venom is capable of doing”, though Fitzsimons (1919) has recorded the potency of Boomslang venom. Besides being dangerously poisonous to man, this is a familiar and abundant South African species which might well have been mentioned here. (1) Reptiles of the World: the Crocodilians, Lizards, Snakes, Turtles and Tortoises of the Eastern and Western Hemispheres. By Dr. Raymond L. Ditmars. New revised edition. Pp. xx + 321 + 90 plates. (London: John Lane, The Bodley Head, Ltd., 1933.) 18s. net. (2) A Monograph of the Frogs of the Family Microhylidae By H. W. Parker. Pp. viii + 208. (London: British Museum (Natural History), 1934.) 15s.