Polyvalent Snake Antivenom Research Articles

Locked-in syndrome as a presentation of snakebite

Snake bite is a common condition in tropical countries. Neurotoxic features of snake bite vary from early morning neuroparalytic syndrome to various cranial nerve palsies. Locked in syndrome (LIS) is a rare presentation. We present four children that had LIS; three patients had total and one had incomplete LIS. All patients made successful recovery with polyvalent anti-snake venom and supportive management. This case series highlights the importance of early diagnosis of LIS in snake bite.

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.

Presentation and outcome of snake bite among children in Sokoto, North-Western Nigeria

Background: Snake bite with envenomation is a medical emergency. Children are at risk of severe manifestations due to small body mass. Unlike adult population, there is limited data on snake bite among children in Sokoto, North-Western Nigeria. We described the presentation and outcome of snake bite in children presenting to the Emergency Pediatric Unit of Usmanu Danfodiyo University Teaching Hospital, Sokoto. Materials and Methods: Case records of all children managed for snake bites from 1 st January 2003 to 31 st December 2012 were retrospectively reviewed. Demographic and other relevant information were retrieved and data analyzed using Microsoft Excel. Results: Out of 23,570 Pediatric admissions, 36 children had snake bites giving prevalence of 0.0015 (1.5/1000). Male: Female ratio was 1.6:1, with a mean (standard deviation) age of 9.6 ± 2.8 years (range = 1-14 years). Snakebites involved the lower limbs in 52.8%; and at home in 69.4%, and during the night in 58.3% of patients. The highest prevalence of bite was between April and July. Features of envenomation included local swelling (100%), prolonged clotting time (61.1%) and spontaneous hemorrhage (epistaxis and hematemesis) in 11.1%. One patient (2.8%) had seizure which may be incidental, though common causes such as hypoglycemia, malaria and meningitis were excluded by laboratory investigations. Polyvalent anti-snake venom was administered in 29 (80.6%) children, with adverse reaction observed in 13.8% (4/29) of the patients. Thirteen patients (36.1%) signed against medical advice while the remaining 23 (63.9%) were discharged home. Conclusion: Snake envenomation is associated with low morbidity and mortality in our study. Measures aimed at eliminating snake habitats around residential areas should be encouraged.

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.

Mortality Predictors of Snake Bite Envenomation in Southern India—A Ten-Year Retrospective Audit of 533 Patients

Snake bite incidence is highest in Asia and sub-Saharan Africa. This retrospective audit of 533 adult patients, who had presented to the Emergency Department, collates clinical features, effect of pharmacologic interventions and the risk factors that influence morbidity and mortality. Dual toxicity, neurological and haematological, was observed in 30.4% of patients. Laboratory evidence of haematotoxicity was demonstrated in 314 (58.9%) and 40% demonstrated clinical evidence of bleeding. However, 7.3% of these patients did not have laboratory evidence of bleeding disorder (p < 0.001). Conversely, 60% did not have clinical evidence of bleeding, but demonstrated laboratory evidence of abnormal parameters. Acute kidney injury (AKI) was evident in 28% of patients and 15.3% required haemodialysis. About 25% with no haematotoxicity showed evidence of AKI. The majority received 6-12 vials of poly-valent anti-snake venom. Hypersensitivity reaction rate was 8% and predominantly anaphylactoid in nature. The length of hospital stay ranged from 2 to 28 days and 20% required mechanical ventilation. Overall mortality rate was 7.5% with significant association to AKI, haematotoxicity and assisted ventilation. The mortality rate was 18% in patients with pre-hospital delay more than 24 h, as against 5% when admitted within the above specified period (p = <0.001). The strength of this study is the accrued information of over a period of 10 years of snake-bite management through the Emergency Department of a university hospital setting. The limitations are the retrospective study design and the rejection percentage of 15.5% due to insufficient information from the total chart pool.

Cerebellar infarct with neurogenic pulmonary edema following viper bite

Russell's viper (Daboia russelli) bites are well known to cause bleeding complications. However, thrombotic complications are rare. We present the case details of a female who was bitten by a Russell's viper (Daboia russelli) in her village. She then developed features of envenomation in the form of hemorrhagic episodes. She received 27 vials of polyvalent anti-snake venom to which the hemorrhagic complications responded. After about 48 h of the bite she developed features of cerebellar infarct along with pulmonary edema which was in all probability neurogenic in origin. She was managed with mechanical ventilation and extra ventricular drainage with good recovery. We discuss the likely pathogenesis of the infarct and pulmonary edema occurring in a patient with viper bite and other features of envenomation.

Terrestrial Snakebites in the South East of the Arabian Peninsula: Patient Characteristics, Clinical Presentations, and Management

BackgroundTo describe the characteristics, clinical presentations, management and complications of snakebites in the border region between Al-Ain, United Arab Emirates (UAE) and Buraimi, Sultanate of Oman.Methodology/Principal FindingsWe carried out a retrospective review of medical records to study snakebite cases over four-year duration at three tertiary hospitals. Overall, 64 snakebite cases were studied with median hospitalization of 2 (interquartile range [IQR] 1–4) days. The majority of cases were male (87.5%), and most (61%) of the incidents occurred during summer months. The bite sites were predominantly (95%) to the feet and hands. Main clinical features included pain, local swelling, and coagulopathy, blistering and skin peeling. Overall, there were no deaths, but few major complications occurred; extensive skin peeling (n = 5, 8%), multi-organ failure (n = 1, 1.5%), and compartment syndrome (n = 1, 1.5%). Polyvalent anti snake venom (ASV), analgesia, tetanus toxoid, intravenous fluids, and antibiotics such as ampicillin, cloxacillin, and cephalosporins were commonly instituted as part of treatment protocols in the three hospitals.ConclusionThe overwhelming majority of bites occurred during summer months, and envenomations were more common in, relatively, young male farmers, but with no serious clinical complications. Prevention and treatment strategies should include increasing public awareness, developing management guidelines, and manufacturing specific ASV for a wide spectrum of the local venomous snakes.

Prevalence of snakebites in Taraba and Plateau States of Nigeria

Snakebite is a public health problem that plagues many rural communities in Nigeria. The full extent is hardly known due to outright unavailability of adequate medical records to indicate the incidence, mortality and morbidityin any state in Nigeria. This study was undertaken to outline the epidemiological profile of snakebites in the middle belt region of Nigeria, using Plateau and Taraba States as a case study. Records of 917 cases of snakebites from eight secondary health facilities, spread across the two states were collected retrospectively, covering January 1999 to December 2003. The data (age, sex and occupation of victims, monthly variation in incidence and prevalence) were extracted. This was analyzed using chi-square test and simple percentages. The results showed that the average male to female preponderance ratio was 2.1:1. Adults between the ages of 15 and 44 years accounted for 62.9% (n=592) of all cases. 41.1% (n=340) of victims were farmers. The average case fatality rate was 13.7% (n=126); with 19.1% (n=64) for Plateau State. The highest incidence of 40.4 bites per 100000 per year occurred in Taraba State. Polyvalent antisnake venom (ASV) was given to all the patients managed. Snake bite is endemic in these areas and accounts for significant morbidity and mortality among the indigenous population.

Neutralizing effect of plant Andrographis paniculata against the Russell′s viper venom and its comparison with polyvalent anti-snake venom

Background: The study was undertaken to investigate the neutralizing effect of the alcoholic extract of Andrographis paniculata against the Russell’s viper venom. Materials and Methods: The lethal dose 99 (LD99) value of snake venom was calculated and then the venom-neutralizing ability of the plant extract at doses of 1 and 2 g/kg was determined using in vitro and in vivo methods. The alleviation in the mean survival time of the animals was used to infer the antivenom property of the drug after challenging it with the LD99 value of snake venom. Results: The ethanolic extract of plant A. paniculata signifi cantly increases the mean survival time and the protection fold but could not protect animals from death when used alone. The protection was more when the plant extract was given at a lower dose, i.e., 1 g/kg, than at a higher dose, i.e., at 2 g/kg. Polyvalent antisnake venom (ASV) was found to be more effective than the plant extract. When the plant extract was given along with polyvalent ASV, it potentiated its effect. Conclusion: The observation demonstrates that the ethanolic extract of A. paniculata has an antivenom activity against the Russell’s viper venom which is comparable with polyvalent ASV.

Anti-cobra venom activity of plant Andrographis paniculata and its comparison with polyvalent anti-snake venom

Background:To investigate the anti-cobra venom effect of alcoholic extract of Andrographis paniculata.Materials and Methods:After calculating the LD99 of snake venom, the venom-neutralizing ability of plant extract at the dose 1 g/kg and 2 g/kg was determined using in vitro and in vivo methods. The alleviation in the mean survival time of the animals were used to infer the antivenom property of the drug after challenging with LD99 of snake venom.Results:The ethanolic extract of plant A. paniculata significantly increases mean survival time and the protection fold, but could not protect animals from death when used alone. The higher dose, i.e., 2 g/kg was found better than that of the lower. ASV was found more effective than the plant extract. When ASV was given along with plant extract, it potentiates its effect.Conclusion:The observation demonstrates the anti-cobra venom activity of ethanolic extract of A. paniculata which is comparable with ASV.

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.

Antisnake venom in a neonate with snake bite

There is no report of the use of antisnake venom (ASV) in the neonatal age group in literature. We report a 27 days old female neonate who presented with neuroparalytic manifestations of snake bite and was treated successfully with ASV. A total of 50 vials (500 mL) of polyvalent antisnake venom were given as infusion in hourly aliquots of 50 mL, over 72 hours.

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...

Anti-snake venom: use and adverse reaction in a snake bite study clinic in Bangladesh

Snakebites can present local or systemic envenomation, while neurotoxicity and respiratory paralysis are the main cause of death. The mainstay of management is anti-snake venom (ASV), which is highly effective, but liable to cause severe adverse reactions including anaphylaxis. The types of adverse reaction to polyvalent anti-snake venom have not been previously studied in Bangladesh. In this prospective observational study carried out between 1999 and 2001, in the Snake Bite Study Clinic of Chittagong Medical College Hospital, 35 neurotoxic-snake-bite patients who had received polyvalent anti-snake venom were included while the ones sensitized to different antitoxins and suffering from atopy were excluded. The common neurotoxic features were ptosis (100%), external ophthalmoplegia (94.2%), dysphagia (77.1%), dysphonia (68.5%) and broken neck sign (80%). The percentage of anti-snake venom reaction cases was 88.57%; pyrogenic reaction was 80.64%; and anaphylaxis was 64.51%. The common features of anaphylaxis were urticaria (80%); vomiting and wheezing (40%); and angioedema (10%). The anti-snake venom reaction was treated mainly with adrenaline for anaphylaxis and paracetamol suppository in pyrogenic reactions. The average recovery time was 4.5 hours. Due to the danger of reactions the anti-snake venom should not be withheld from a snakebite victim when indicated and appropriate guidelines should be followed for its administration.

Clinical profile of venomous snake bites in north Indian military hospital

Snakebite is an environmental hazard associated with significant morbidity and mortality. We report a case series of venomous snakebites in a military operational area of north India. Of 33 cases of snake bites presenting to the military hospital, 21 patients were envenomated. The median age of patients was 24 years; all were men. All of the envenomations were neurotoxic in nature. Abdominal pain (91%), headache (86%), dysphagia (86%), ptosis (77%), diplopia (72%), blurred vision (72%), dyspnea (67%), and vomiting (62%) were the predominant clinical presentation. Polyvalent AntiSnakeVenom (ASV) [mean 180 ml; range 90-320 ml] was given to all patients with systemic manifestations, and repeated as needed. Eleven (52%) patients received neostigmine with glycopyrrolate to counter cholinergic effects. Two patients were given ventilatory support. The average time of recovery from envenomation was 16 hours after administration of ASV. All patients recovered without sequelae. Soldiers during military exercise are vulnerable to snakebites. Neurotoxic snakebites predominate in our study and usually present with autonomic features along with headache, abdominal pain, ptosis, diplopia and dysphasia. Preventive measures to minimize snake bites and planned treatment regimens should be emphasized among medical and military personnel deployed in the field operations.

Snakes of Medical Significance in India: The First Reported Case of Envenoming by the Levantine Viper ( Macrovipera lebetina)

This article reports for the first time the medical significance of the Levantine viper (Macrovipera lebetina) in India. This snake is found in India in the mountainous regions of Jammu and Kashmir and is capable of causing necrosis and hemostatic manifestations, as seen in the case reported here. It is thus a class II snake of medical significance, as defined by the World Health Organization grading scale. This finding reinforces the recent decision by the Indian Government to abandon the term "Big Four" to describe important venomous species in India. Levantine viper venom is not included in the manufacture of Indian polyvalent anti-snake venom; thus, there is no current antidote for this species. Recommendations are to manage confirmed bites from this species without Indian anti-snake venom. In areas where this snake is found to be a significant contributor to envenomations, alternative anti-snake venoms can be sourced from outside India for use in high-risk groups. Continuing attention to preserving dead snakes brought with the victim for reliable identification remains a high priority.

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.