Polyvalent Snake Research Articles

An examination of cardiovascular collapse induced by eastern brown snake (Pseudonaja textilis) venom

The Pseudonaja genus (Brown snakes) is widely distributed across Australia and bites account for significant mortality. Venom-induced consumption coagulopathy (VICC) and, less often, early cardiovascular collapse occur following envenoming by these snakes. We have previously examined possible mechanism(s) behind the early cardiovascular collapse following Papuan taipan (Oxyuranus scutellatus) envenoming. In the present study, we investigate early cardiovascular collapse in anaesthetized rats following administration of eastern brown snake (Pseudonaja textilis) venom, and prevention of this effect with prior administration of ‘priming’ doses (i.e. doses of venom which caused a transient hypotensive response) of venom. P. textilis venom (5–10μg/kg, i.v.) induced cardiovascular collapse in anaesthetized rats, characterized by a rapid decrease in systolic blood pressure until non recordable. Prior administration of ‘priming’ doses of P. textilis venom (2 and 3μg/kg) or, at least, 4–5 doses of O. scutellatus (2μg/kg, i.v.) or Daboia russelii limitis (20μg/kg, i.v.) venoms prevented cardiovascular collapse induced by P. textilis venom. Moreover, early collapse was also inhibited by prior administration of 2 discrete doses of Acanthophis rugosus venom. Prior administration of commercial polyvalent snake antivenom (500–3000units/kg, i.v.) or heparin (300units/kg, i.v.) also inhibited P. textilis venom-induced cardiovascular collapse. Our results indicate that P. textilis venom-induced cardiovascular collapse can be prevented by prior administration of sub-lethal doses of venom from P. textilis, O. scutellatus, A. rugosus and D. russelii limitis. This suggests that sudden cardiovascular collapse following envenoming is likely to involve a common mechanism/pathway activated by different snake venoms.

A hospital based epidemiological study of snakebite in Western Development Region, Nepal

Snakebite is an important and serious medical problem throughout the entire terai region of Nepal. But comprehensive study of snakebite epidemiology in Western Development Region of Nepal is scarce. We described the status of snakebite situation in the region based on retrospective data retrieved from 10 snakebite treatment centers during June 2011 to February 2012. We reported six thousand and nine hundred ninety three snakebites in 2008–2010. Of all, we found 640 (9%) cases envenomed and received anti-venom therapy. We recorded the highest number of snakebites in July, August and September, which account 57% of all snakebite victims, during 15.00 and 21.00 h. People aged 11–20 years were mostly victimized by snakebite as compared to other age groups. Female suffered more than male. The average requirement of polyvalent snake anti-venom was 16 vials. Overall, case fatality rate was 13%.

Successful snakebite treatment in three juvenile African wild dogs (<i>Lycaon pictus</i>) with polyvalent antivenom: A Namibian case report

This article reports the first documented treatment of venomous snakebite with a polyvalent snake antivenom from the South African Institute for Medical Research in endangered African wild dogs (Lycaon pictus). Three juvenile male animals (6.5 months of age) showed clinical signs after being bitten by an unidentified venomous snake. The signs included loss of appetite, disorientation, impaired locomotion, excessive facial swelling, profuse salivation, reduced respiratory effort and an apparent depressed mental state. Intravenous treatment with isotonic Ringer lactate solution, hetastarch 6% and dexamethazone, subcutaneous administration of procaine benzylpenicillin and benzathine benzylpenicillin, and ultimately intravenous administration of the polyvalent snake antivenom resulted in the complete recovery of all three wild dogs.

Cross neutralization of Afro-Asian cobra and Asian krait venoms by a Thai polyvalent snake antivenom (Neuro Polyvalent Snake Antivenom).

BackgroundSnake envenomation is a serious public health threat in the rural areas of Asian and African countries. To date, the only proven treatment for snake envenomation is antivenom therapy. Cross-neutralization of heterologous venoms by antivenom raised against venoms of closely related species has been reported. The present study examined the cross neutralizing potential of a newly developed polyvalent antivenom, termed Neuro Polyvalent Snake Antivenom (NPAV). NPAV was produced by immunization against 4 Thai elapid venoms.Principal Findings In vitro neutralization study using mice showed that NPAV was able to neutralize effectively the lethality of venoms of most common Asiatic cobras (Naja spp.), Ophiophagus hannah and kraits (Bungarus spp.) from Southeast Asia, but only moderately to weakly effective against venoms of Naja from India subcontinent and Africa. Studies with several venoms showed that the in vivo neutralization potency of the NPAV was comparable to the in vitro neutralization potency. NPAV could also fully protect against N. sputatrix venom-induced cardio-respiratory depressant and neuromuscular blocking effects in anesthetized rats, demonstrating that the NPAV could neutralize most of the major lethal toxins in the Naja venom.Conclusions/SignificanceThe newly developed polyvalent antivenom NPAV may find potential application in the treatment of elapid bites in Southeast Asia, especially Malaysia, a neighboring nation of Thailand. Nevertheless, the applicability of NPAV in the treatment of cobra and krait envenomations in Southeast Asian victims needs to be confirmed by clinical trials. The cross-neutralization results may contribute to the design of broad-spectrum polyvalent antivenom.

First reported case of African viper bite treated with Indian polyvalent anti snake venom

Dear Editor, The compositional differences between venoms among different geographic regions may be due to evolutionary environmental pressure acting on isolated populations. The polyvalent variety of anti snake venom (ASV) with local specificity remains the mainstay of therapy in most countries. ASV against the venom of one species occasionally may have partial cross neutralizing activity against other venoms, usually from closely related species, known as paraspecific activity. We managed a case of an African viper bite successfully using Indian polyvalent ASV as the specific African variety was not available to us. A 25 year old serving soldier of a foreign army contingent in UN mission in the Democratic Republic of Congo, was brought on 29 Sep 07 at 0025 hours, with a history of a mildly painful snake bite of about two hours duration on the left foot. There was no history suggestive of neurological involvement. Clinical examination revealed normal vital parameters and a normal general examination. Local exam revealed swelling and tenderness of left foot extending beyond the ankle to the distal leg. Two fang marks 1.5 cm apart were visible on dorsum of left foot along with a small patch of ecchymosis (Fig. 1). Fig. 1 Fang marks with swelling of foot. A bed side whole blood clotting time revealed no clotting at 30 minutes, with a clotting time of 35 minutes by capillary method. Bleeding time was in normal range. Since specific ASV for the regional area was not available, a decision to give Indian polyvalent ASV (which was available) was taken as an emergency life saving measure. A total of 150 ml of reconstituted ASV (15 vials of polyvalent Indian variety) was administered as per standard protocol over next nine hours in view of progressively increasing swelling in the leg and deranged clotting time in range of 15 to 21 minutes. The progression of the swelling of the limb halted and clotting parameters started improving (Fig. 2). Antibiotics and other supportive therapy were given. The patient had a haemoglobin drop from 16.3 to 13.6 gm per dl and mild thrombocytopenia in range of 1,20,000 to 1,40,000/mm2 during the initial few days which subsequently recovered. He also developed an uncomplicated resolving small abdominal wall hematoma (confirmed by ultrasound). He was discharged at three weeks with a complete and uneventful recovery. Fig. 2 Reduction of swelling of the limb by day three. The mortality after untreated viper bites like Crotalus durissus terrificus is said to have been up to 70 %, but this has been reduced to less than 12% by ASV treatment and in African varieties like Atractaspis and bush vipers (like those found in the Congo basin) the mortality ranges from 8-43% [1, 2]. “Specific” antivenom, implies that the antivenom has been raised against the venom of a particular snake that has bitten the patient (Monovalent or monospecific antivenom). Polyvalent antivenom neutralises the venoms of several different species of snakes. FAV AFRICA is the polyvalent equine ASV recommended for Sub-Saharan African snakes. The Indian ASV contains sera against the saw scaled viper, Russel's viper. Indian Cobra (Naja naja) and the banded krait. Analysis of Indian cobra (Naja naja) venom samples from eastern, western and southern India revealed differences in composition, biochemical, and pharmacological properties emphasizing regional variation: continents will logically be different [3]. There are only a handful of documented cases of snake bites managed with ASV pertaining to different geographical locations. Use of Tiger Snake ASV in Stephen's Banded Snake envenomation in Australia, pit viper envenomation (South American) treated with nonspecific ASV and two North American coral snake venoms treated with Mexican ASV have been described [4, 5, 6]. A study was performed to assess the ability of polyvalent anti snake venom VACSERA (produced by Egypt), to neutralize venoms of snakes not only from Egypt but also African and Middle Eastern habitats showed encouraging results [7]. There is a description of a severe systemic envenomation of a African bush viper managed successfully with Near Middle East ASV [8]. Ours is possibly the first reported case of an African viper bite successfully managed with Indian polyvalent ASV given in the backdrop of unavailability of specific antisera. We recommend that more studies be carried out on this paraspecific activity of the Indian ASV.

Management of snakebites at a rural South African hospital

AbstractBackground: Snakebites remain a source of considerable morbidity and mortality in many countries, with an estimated global true incidence of envenomation exceeding five million a year, with about 100 000 of these cases developing severe sequelae. Despite the availability of polyvalent snake antivenom, inappropriate first aid, regional effects of envenomation and inappropriate use of antivenom result in significant and at times potentially avoidable morbidity and mortality, particularly in children. The study was undertaken in Lephalale (previously Ellisras) Hospital, Limpopo Province, due to the frequency of snakebites managed at the hospital.Methods: This was a record-based retrospective study in which patient files with the diagnosis of snakebite were reviewed. The objective of this study was to document the management of snakebites at Lephalale Hospital, a rural hospital in South Africa. The hospital files of all patients managed at the hospital for snakebites from 1 January 1998 to 31 December...

A cell-based assay for screening of antidotes to, and antivenom against Chironex fleckeri (box jellyfish) venom

Introduction Chironex fleckeri is a large box jellyfish that has been labelled the ‘most venomous animal’ in the world. We have recently shown that the primary effect of C. fleckeri venom in vivo is cardiovascular collapse. This study utilised a cell-based assay to examine the effects of C. fleckeri venom on the proliferation of a rat aortic smooth muscle cell line. In addition, the ability of CSL box jellyfish antivenom and/or various potential treatment strategies to neutralise the effects of the venom was examined. Methods A7r5 cells were cultured in media containing venom. The effect of CSL box jellyfish antivenom (5 U/mL), CSL polyvalent snake antivenom (5 U/mL), lanthanum (5 µM), MgSO 4 (50 mM), verapamil (5 µM) or felodipine (5 µM) was examined. Cell viability was determined using a Cell titer 96 AQueous One Solution cell proliferation assay. Results Incubation of A7r5 cells with serially diluted venom (2–0.004 µg/mL) caused a concentration-dependent inhibition of cell proliferation with an IC 50 value of 0.056 µg/mL. This response was not affected by the absence of calcium or the presence of lanthanum in the media. Box jellyfish antivenom (5 U/mL) prevented the inhibition of cell proliferation caused by the venom. Verapamil (5 µM) had no significant effect on the inhibition. In contrast, felodipine (5 µM) or MgSO 4 (50 mM) potentiated the effects of the venom and partially negated the protective effect of the antivenom. Discussion This study displayed the ability to utilise a cell-based assay to determine the effects of C. fleckeri venom on vascular cell viability. It showed that CSL box jellyfish can neutralise the effects of the venom but only if added prior to the venom. In addition, potential adjunct therapies verapamil, felodipine and MgSO 4 were found to be ineffective, with felodipine and MgSO 4 potentiating the detrimental effects of the venom.

Comparison of Montanide adjuvants, IMS 3012 (Nanoparticle), ISA 206 and ISA 35 (Emulsion based) alongwith incomplete Freund's adjuvant for hyperimmunization of equines used for production of polyvalent snake antivenom

The use of adjuvant is of fundamental importance in vaccines formulations and antisera production. Currently selection and use of adjuvant systems in snake antivenom preparation has become a major issue in terms of animal welfare as well as economics. In order to minimize disadvantages associated with traditionally used Freund's adjuvant (FA) in equines and to produce potent polyvalent antivenom against four Indian snake venoms in minimum possible period, a comparison was made between various commercially available non-emulsion/emulsion based adjuvants like IMS 3012, ISA 206 and ISA 35 with Incomplete Freund's adjuvant (IFA) for their immunopotentiation capacity and safety in donor animals.The present study was conducted in 33 new horses, randomly divided into four groups and hyperimmunized using crude mixture of snake venoms, viz.; Cobra venom (CV), Russell's viper venom (RV), Krait venom (KV) and Saw-scaled viper (EV) along with four above mentioned adjuvants through subcutaneous (s.c.) route at intervals of two weeks. Periodic standard safety assessments were done. Immunopotentiation ability of each adjuvant group in terms of percent responders were estimated at 14th, 21st, 30th and 43rd week. The neutralization activity (ED50) of pooled sera samples by 43rd week, obtained with IMS 3012 group for CV, RV, KV and EV venoms were 0.133, 0.143, 0.070 and 0.270mg venom/ml of serum respectively. The antivenom potency with IMS 3012 and overall responding horses (100%) even against weak immunogen like CV was significantly higher (p<0.05) than other three adjuvants studied. The horses of IMS 3012 group showed minimum local reactions at injection site, while horses from other three groups exhibited moderate (++) reactions; 66.7% in ISA 206, 12.5% in ISA 35 and 14.3% in IFA respectively, however these were transient and reabsorbed or healed subsequently.Finally, we conclude that, nanoparticle adjuvant IMS 3012 could be a possible alternative to the emulsion adjuvants for primary phase of immunization in antivenom preparation considering its better immunopotentiation capacity and safety in donor animals.

Snakebite envenoming in Kerala, South India: clinical profile and factors involved in adverse outcomes

Background:Snakebite envenoming is an important medical emergency in Kerala, but the factors leading to complications have not been well studied.Objectives:To study the clinical characteristics, factors involved in complications and the...

The in vitro Neurotoxic and Myotoxic Effects of the Venom from the Suta Genus (Curl Snakes) of Elapid Snakes

Australia has a tremendous diversity of elapid snakes, including many unique smaller sized species of this venomous snake family. However, little if anything is known about the majority of the venoms of these lesser studied snakes. In the current study, the venoms of Suta suta (curl snake) and Suta punctata (spotted-curl snake) were examined for in vitro activity using a skeletal muscle preparation (i.e. chick biventer cervicis nerve-muscle preparation). Both venoms caused concentration-dependent (3-10 microg/ml) inhibition of nerve-mediated twitches, and inhibited responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. These effects were prevented by prior addition of CSL Ltd. polyvalent snake antivenom (5 units/ml) but only partially reversed by the addition of antivenom (5 units/ml) at the t(90) time-point (i.e. time at which twitches were inhibited by 90%). Suta punctata venom (10 microg/ml) was also myotoxic as indicated by the inhibition of direct twitches of the chick biventer cervicis nerve-muscle preparation. This effect was not reversed by antivenom (5 units/ml). This study highlights the danger of underestimating the potential severe clinical effects posed by these small but highly venomous snakes.

A case report of scrotal gangrene from snake bite

A case of snake bite of the scrotum in a 43-year-old male Fulani farmer cum herdsman is presented. Gangrene of the scrotum developed 4 days after the bite together with an increase in size of the scrotum to about 59cm in circumference. The patient received polyvalent snake anti venom almost 10 hours after the bite. Surgery to excise the gangrenous part, together with multiple longitudinal skin incisions of scrotum and penis were carried out The scrotal size reduced to almost half of the morbid size within 48 hours of surgery.

IN VITRO NEUROTOXIC AND MYOTOXIC EFFECTS OF THE VENOM FROM THE BLACK WHIP SNAKE (DEMANSIA PAPUENSIS)

1. Black whip snakes belong to the family elapidae and are found throughout the northern coastal region of Australia. The black whip snake (Demansia papuensis) is considered to be potentially dangerous due to its size and phylogenetic distinctiveness. Previous liquid chromatography-mass spectrometry analysis of D. papuensis venom indicated a number of components within the molecular mass ranges compatible with neurotoxins. For the first time, this study examines the in vitro neurotoxic and myotoxic effects of the venom from D. papuensis. 2. Venom (10 microg/mL) caused significant inhibition of twitches elicited by stimulation (0.2 ms, 0.1 Hz, supramaximal V) of motor nerves in the chick biventer cervicis nerve-muscle preparation. This neurotoxic effect, which was postsynaptic in origin, was weak in comparison to that of most other Australian elapids. Prior addition (10 min) of polyvalent (PSAV) or tiger snake (TSAV) antivenom (5 units/mL) prevented venom-induced twitch inhibition. Addition of PSAV (5 units/mL) at t(50) failed to reverse the inhibitory effect but prevented further inhibition of nerve-mediated twitches. 3. The venom (20-50 microg/mL) is also myotoxic as indicated by a slowly developing contracture and inhibition of twitches elicited by direct stimulation (2 ms, 0.1 Hz, supramaximal V, in the presence of tubocurarine 10 micromol/L) of the chick biventer muscle. This activity was confirmed by histological examination of the muscle. 4. Fractionation and characterization of venom components is required to further investigate the reasons for the weak neurotoxic activity of D. papuensis venom.

Phospholipase A2‐dependent effects of the venom from the new guinean small‐eyed snake Micropechis ikaheka

The New Guinean small-eyed snake (Micropechis ikaheka) is a cause of life-threatening envenoming. Previous studies on M. ikaheka venom have indicated the presence of neurotoxins as well as myotoxins. This study examined the in vitro myotoxic effects of M. ikaheka venom and the efficacy of a polyvalent antivenom in neutralizing these effects. Venom (50 microg/ml) produced a slowly developing contracture and inhibition of direct twitches of the chick biventer cervicis nerve-muscle preparation in the presence of tubocurarine (10 microM). Myotoxicity was confirmed by subsequent histological examination of tissues. This myotoxicity was prevented by the prior addition of polyvalent snake antivenom (30 U/ml). However, the addition of antivenom (30 U/ml) 1 h after venom administration failed to reverse or prevent the further inhibition of direct twitches. In addition, venom (1-10 microg/ml) produced concentration-dependent contractions of the guinea-pig isolated ileum. These effects were dependent on phospholipase A2 (PLA2) activity of the venom as evidenced by the ability of the PLA2 inhibitor 4-bromophenacyl bromide (4-BPB; 1.8 mM) to prevent this activity. This study indicates that M. ikaheka venom causes significant myotoxicity and that polyvalent snake antivenom may be a potential treatment for the myotoxic effects in patients envenomed by this species.

Presynaptic neuromuscular activity of venom from the brown-headed snake ( Glyphodon tristis)

The brown-headed snake ( Glyphodon tristis) inhabits the forest regions of Papua New Guinea, Torres Strait Islands, and far northern Queensland, Australia. Although bites by Glyphodon dunmalli have been reported, G. tristis was regarded as innocuous until 1989 when a healthy 20 year old man was bitten (Sutherland, S.K., Tibballs, J., 2001. Australian Animal Toxins, the Creatures, their Toxins and Care of the Poisoned Patient. University Press, Oxford). Treatment of envenomation by this species is empirical with no specific antivenom available. While no published studies on the venom of G. tristis are available, unpublished studies suggest neurotoxicity as being the main symptom of envenomation. In this study, the in vitro effects of G. tristis venom were examined using the chick biventer cervicis nerve muscle (CBCNM) preparation. Venom (10 μg/ml) inhibited indirect (0.2 ms, 0.1 Hz, supramaximal V) twitches of the CBCNM. This inhibition appeared to be presynaptic in origin as evidenced by the lack of effect of venom on responses to exogenous acetylcholine (1 mM), carbachol (20 μM) and KCl (40 mM) in the non-stimulated CBCNM. Prior addition (10 min) of polyvalent snake antivenom (5 U/ml; CSL Ltd) attenuated twitch inhibition. The venom (10–50 μg/ml) also appears to be myotoxic as indicated by a slowly developing contracture and inhibition of direct (2 ms, 0.1 Hz, supramaximal V, in the presence of tubocurarine 10 μM) twitches. Myotoxicity was confirmed by subsequent histological examination of tissues. This myotoxicity was prevented by the prior addition of polyvalent snake antivenom (30 U/ml). The phospholipase A inhibitor 4-BPB (1.8 mM) significantly attenuated the inhibition of indirect and direct twitches of the CBCNM preparation, indicating the involvement of a PLA 2 component in the toxic action of the venom.

Cardiovascular, haematological and neurological effects of the venom of the Papua New Guinean small-eyed snake ( Micropechis ikaheka) and their neutralisation with CSL polyvalent and black snake antivenoms

Cardiovascular and haematological effects of venom of the small-eyed Snake ( Micropechis ikaheka) were examined in ventilated anaesthetised piglets. Neurotoxic effects were examined in chick biventer cervicis nerve-muscle preparations. Immunoreactivity of venom was tested against the monovalent antivenom components in a CSL Ltd Venom Detection Kit. Neutralisation was tested in vivo and in vitro with CSL Ltd polyvalent snake and Black Snake ( Pseudechis australis) antivenoms. Venom in 0.1% bovine serum albumin in saline was infused into piglets in doses 1–2000 μg/kg. Pulmonary hypertension ( P=0.0007) and depression of cardiac output ( P=0.002) were observed up to 3 h after 150–160 μg/kg. The concentration of plasma free-haemoglobin increased more than 50-fold, indicating haemolysis. Neither coagulopathy nor thrombocytopenia occurred. Creatine phosphokinase and serum potassium levels did not increase suggesting absence of acute rhabdomyolysis. The venom caused post-synaptic neurotoxicty. Immunoreactivity of venom with Black Snake antivenom was observed at very high venom concentrations. Cardiovascular effects were absent and haemolysis was less after venom was pre-incubated at 37 °C for 30 min with polyvalent antivenom. Neutralisation by Black Snake antivenom was less effective. The neurotoxicity was neutralised by polyvalent or Black Snake antivenoms. Human envenomation may be treated with CSL Ltd polyvalent snake antivenom.

Tissue necrosis after canine bothropic envenoming: a case report

The authors report a case of bothropic envenoming in a male Cocker Spaniel. The animal was bitten in the ventral thoracic region, receiving treatment 4 hours later. Clinical examination revealed an extensive, painful and area of firm edema, absence of local or systemic hemorrhage, without evident neurological alterations. Clinical diagnosis was mild bothropic envenoming. Treatment consisted of 5 vials of polyvalent snake antivenom, two vials administered intravenously and three subcutaneously. Blood clotting time was always within normal values. Two days after envenoming, the animal showed hyperthermia and received enrofloxacin (5mg/kg/24h) for 10 days and ketoprofen (1mg/kg/24h) for 5 days. Seventy-two hours after envenoming, extensive subcutaneous, muscle fiber, and skin necrosis of approximately 10 cm in diameter was observed. After debridement of necrotic tissues, the area was cleaned with antiseptic solutions. Complete healing was observed 55 days after envenoming. The authors discuss whether heterologous serotherapy is effective in preventing tissue necrosis after bothropic envenoming.

Adjuvant effects and antiserum action potentiation by a (herbal) compound 2-hydroxy-4-methoxy benzoic acid isolated from the root extract of the Indian medicinal plant `sarsaparilla' ( Hemidesmus indicus R. Br.)

The adjuvant effect and antiserum potentiation of a compound 2-hydroxy-4-methoxy benzoic acid were explored in the present investigation. This compound, isolated and purified from the Indian medicinal plant Hemidesmus indicus R. Br, possessed antisnake venom activity. Rabbits immunized with Vipera russellii venom in the presence and absence of the compound along with Freund's complete adjuvant, produced a precipitating band in immunogel diffusion and immunogel electrophoresis. The venom neutralizing capacity of this antiserum showed positive adjuvant effects as evident by the higher neutralization capacity (lethal and hemorrhage) when compared with the antiserum raised with venom alone. The pure compound potentiated the lethal action neutralization of venom by commercial equine polyvalent snake venom antiserum in experimental models. These observations raised the possibility of the use of chemical antagonists (from herbs) against snake bite, which may provide a better protection in presence of antiserum, especially in the rural parts of India.

High incidence of early anaphylactoid reaction to SAIMR polyvalent snake antivenom

During a prospective study of 147 patients with snakebite presenting to a rural South African hospital, 13 of 17 patients (76%) treated with South African Institute for Medical Research (SAIMR) polyvalent antivenom experienced potentially severe early (anaphylactoid) reactions. The most common reaction was generalized urticaria (12; 71%), but 3 cases of angio-oedema (18%), 2 of bronchospasm (12%), and 2 of hypotension (12%) were also observed. Reactions were controlled with adrenaline, antihistamines, and resuscitation. All patients fully recovered from envenoming although the full dose of antivenom was not given to most. Indications for the use of this antivenom should be reconsidered and patients should be given antivenom in a high care setting if possible. Use of antivenom by lay people outside hospital should be discouraged and antivenom manufacturing processes could usefully be reviewed.

Viper venom neutralization by Indian medicinal plant (Hemidesmus indicus andPluchea indica) root extracts

The methanol root extracts of Hemidesmus indicus R. Br. and Pluchea indica (Less) were explored for the first time for neutralization of snake venom (Vipera russellii) activity. The H. indicus and P. indica root extracts significantly neutralized the viper venom-induced lethality and haemorrhagic activity in albino rat and mouse. Venom-induced coagulant and anticoagulant activity was also antagonized by both the extracts. No precipitating bands were observed between the plant extract and polyvalent snake venom antiserum. Maximum neutralization was achieved by H. indicus root extract. These observations confirmed that certain Indian medicinal plants possess significant snake venom neutralizing capacity and need further examination for their active constituents.

Immunological studies on Iranian scorpion venom and antiserum

Studies on seven species of scorpion collected from various parts of Iran indicated that the yield and toxicity of venom of these arthropods varied. The lethality of the venom was determined following i.v. injection into mice. A polyvalent serum against the venoms of the Iranian scorpions Androctonus crassicauda, Buthotus saulcyi, Hemiscorpius lepturus, Mesobuthus eupeus, Odontobuthus doriae and Scorpio maurus was prepared in horses. The venom was obtained either by electrical stimulation or by extraction of the macerated telsons and was freeze-dried. The venom extracted by electrical stimulation of the telson was higher in lethality than the venom prepared by maceration of the telson. The crude serum was purified and concentrated by enzyme digestion and salt fractionation and examined for its neutralization power by injecting mixtures of the venom and serum into mice, as well as for precipitating antibodies by the immunodiffusion technique. The scorpion antivenin could neutralize all the venoms used as antigens, and caused the formation of from one to four precipitation bands, depending on the venom. Although it failed to precipitate with any of the venoms, this institute's polyvalent snake antivenin was found to have measurable neutralizing effect on three of the venoms, but none whatever on the venoms of the three medically most important scorpions, Androctonus, Buthotus and Odontobuthus. Thus the administration of snake antivenin in cases of stings in Iran cannot be recommended whereas the polyvalent scorpion antivenin may be used with confidence.