Cross neutralization of Hypnale hypnale (hump-nosed pit viper) venom by polyvalent and monovalent Malayan pit viper antivenoms in vitro and in a rodent model

Hypnale hypnale (hump-nosed pit viper) is a medically important venomous snake in Sri Lanka and Southwestern India. Bite of this snake may result in hemostatic dysfunction, acute kidney injury and death. Clinical studies indicated that the locally available polyvalent antivenoms produced in India are not effective against hump-nosed pit viper envenoming. Hence, there is an urgent need to search for effective antivenom. In this paper, we examined the ability of Calloselasma rhodostoma (Malayan pit viper) monovalent antivenom and the Hemato polyvalent antivenom (both produced by Thai Red Cross Society, TRCS) to neutralize the lethality and toxic effects of H. hypnale venom, as C. rhodostoma is considered a sister taxon of H. hypnale. In vitro neutralization studies showed that the Hemato polyvalent antivenom effectively neutralized the lethality of H. hypnale venom (1.52 mg venom/mL antivenom) as well as the hemorrhagic, procoagulant and necrotic activities of the venom. The monovalent C. rhodostoma antivenom could also neutralize the lethality and toxic activities of the venom, but the potency was lower. The Hemato polyvalent antivenom also effectively protected mice from the lethal and local effects of H. hypnale venom in an in vivo rodent model of envenoming. Furthermore, the polyvalent antivenom could also effectively neutralize the venom of Daboia russelii (2.50 mg venom/mL antivenom), another common cause of snake bites in Sri Lanka and South India. These findings suggested that the Hemato polyvalent antivenom may be beneficial in the antivenom treatment of H. hypnale envenoming.     

The importance of bites by the saw-scaled or carpet viper (Echis carinatus): epidemiological studies in Nigeria and a review of the world literature.

The incidence of Echis carinatus (saw-scaled or carpet viper) bite and its mortality have been investigated in the Nigerian savanna region. A geographical area was defined in which the snake was particularly abundant and bites were frequent. Perennial and seasonal fluctuations in incidence and mortality, the circumstances in which bites occurred and the types of people bitten were studied at Bambur, Zaria, Kaltungo and Gombe hospitals. Peak incidence coincided with the increase in farming during the rains whereas percentage mortality seemed to be greatest during the cold dry season. The majority of the patients were young males bitten on the foot while walking or farming. A review of the world literature indicated that E. carinatus was the principal cause of snake bite morbidity wherever data were available throughout its wide geographical range. Official statistics have seriously underestimated this important rural health problem.     

Management of poisonous snake bites in southern Taiwan

Snake bite envenomation is not uncommon in Taiwan. This study focuses on the pattern of poisonous snake bites and their management in southern Taiwan over a 5-year period. The case histories of 37 patients with poisonous snake bites admitted to the Kaohsiung Medical University Hospital between June 2001 and July 2005 were analyzed retrospectively. Three patients, bitten by unknown species of venomous snakes, were excluded from this study. The frequency of snakebites from each species of snake, the local and systemic manifestations of snake bite, treatment of complications and final outcomes were analyzed. Of the remaining 34 patients, 11 (32.4%) were bitten by bamboo vipers, 10 (29.4%) by Russell's pit vipers, 8 (23.5%) by Taiwan cobras and 5 (14.7%) by Taiwan Habu. The majority of snake bites (28) occurred between May and November. Those affected were mainly outdoor hikers (14) and workers (9). The antivenin requirements for treatment in the emergency room were in accordance with standard procedures. No mortality was noted among those envenomed by poisonous snakes. Although poisonous snake bite is not a common life-threatening emergency in the study area, we observed both an environmental risk and a seasonal incidence of snake bite. Keeping the varied clinical manifestations of snake bite in mind is important for effective management. Ready availability and appropriate use of antivenin, close monitoring of patients, institution of ventilatory support and early referral to a larger hospital when required, all help reduce mortality.     

The effect of green pit viper (Trimeresurus albolabris) venom on platelet morphology by electron microscopy

The incidence of venomous snake bites increases every year in Thailand, especially due to green pit viper. After the bite, there is bleeding due to thrombin-like property of the venom. The mean platelet volume has been reported to be decreased in those who have been bitten by this snake. In this study we investigate the effect of green pit viper venom (Trimeresurus albolabris) on platelet volume (MPV), number and morphology of platelets in vitro. The test was carried out by washing platelets in phosphate buffer at pH 7.2 to remove fibrinogen, then the washed platelets were mixed with green pit viper venom. Platelet morphology was examined by scanning electron microscope (SEM).The morphology of platelets was smaller than normal which ranges from 1.1- 1.2 microm. Green pit viper venom can directly effect platelet morphology, decreasing platelet volume.     

Epidemiology and clinical picture of the Russell's viper (Daboia russelii russelii) bite in Anuradhapura, Sri Lanka: a prospective study of 336 patients

Russell's viper (Daboia russelii russelii) bite is associated with a high incidence of morbidity and mortality in Sri Lanka. Hence, this study enrolled all consecutive Russell's viper bite admissions to the 'Unit A' of General Hospital, Anuradhapura, over a two year period from January 1996, to describe the epidemiology, clinical picture, treatment and outcome. There were 336 cases which showed the following results. The male: female ratio was 5:1; 75% of patients were below the age of 40 years. Biting occurred mainly in paddy fields 41%, and on footpaths 29% at dusk or dawn. Envenoming manifested in 310 (92%) of patients as follows: local swelling 92%, local necrosis 8.9%, coagulopathy 77%, neurotoxicity 78%, nephrotoxicity 18%, cardiac effects 3-12% and myotoxicity 14%. Coagulopathy appeared within 30 minutes to 12 hours after the bite and was corrected within 1 hour to 48 hours (mode 20 hours). Neurotoxicity recovered spontaneously in 1 to 5 days (mode 3 days): however, eight patients needed mechanical ventilation. Thirteen (4%) of patients were managed with peritoneal dialysis because of hyperkalemia caused by a hypercatabolic state (7) and acute renal failure (6). The mortality rate of the series was 2.6% (9 patients). Rural dry zone paddy farmers are the common victims of Russell's viper bite in Sri Lanka and its' envenoming leads to diverse clinical manifestations. Therefore, practically feasible preventive measures should be developed to minimize the incidence of bite and an evidence based management guideline should be developed for hospital practice.     

The legitimacy of rattlesnake bites in central Arizona

Previous authors have classified poisonous snake bites as being legitimate or illegitimate, depending on whether the victim was taking unnecessary risks with a snake before being bitten. We reviewed medical records of 86 consecutive rattlesnake bite victims cared for at a single medical center to determine legitimacy of snake bites. A bite was considered illegitimate if, before being bitten, the victim recognized an encounter with a snake but did not attempt to move away from the snake. A legitimate bite was said to have occurred if a person was bitten before an encounter with a snake was recognized or was bitten while attempting to move away from a snake. The study group was made up of 75 male (87.2%) and 11 female (12.8%) victims. Seventy-four percent were 18 to 50 years old, and 15% had been bitten previously. Only 43.4% of all bites were considered legitimate, and pet (captive) snakes accounted for almost one third of all illegitimate bites. The ingestion of alcoholic beverages was associated with 56.5% of illegitimate bites versus 16.7% of legitimate bites (P less than .001). While 74.4% of bites were to upper extremities, only 27% of upper extremity bites were legitimate. All bites to the lower extremity were legitimate (P less than .001). Of 14 individuals bitten by pet snakes, all were men and 64.3% were under the influence of alcohol at the time of the bite.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bites by the white-lipped pit viper (Trimeresurus albolabris) and other species in Hong Kong. A survey of 4 years' experience at the Prince of Wales Hospital

The case records of 242 snake bite victims admitted to the Prince of Wales Hospital in Hong Kong between September 1984 and October 1988 were studied retrospectively. When the snake was identified, the White-lipped pit viper (Trimeresurus albolabris) was by far the commonest species involved. In addition to local oedema and inflammation, evidence of a significant blood clotting disturbance was present in at least 10% of cases, defibrination and thrombocytopenia being the commonest findings. Since such abnormality was not always sought the true figure is likely to be higher. Three fatalities occurred, one of which was secondary to a probable White-lipped pit viper bite, one to a bite by Chinese cobra and one to a bite by Russell's viper.     

Immunological properties of Hypnale hypnale (hump-nosed pit viper) venom: antibody production with diagnostic and therapeutic potentials

Envenomation by hump-nosed pit viper (Hypnale hypnale, Hh) in Sri Lanka has caused significant morbidity and mortality, attributed to 35% of total venomous snakebites. In Southwestern India (Kerala), H. hypnale was increasingly identified as a dangerous and common source of envenomation, second to the Russell's viper but ahead of the cobra bites. Unfortunately, there is still no specific antivenom to date. This study aims to investigate the immunological properties of the venom and to assess the feasibility of specific Hh antivenom production as well as the development of a diagnostic assay. Hh venom elicited satisfactory titers of anti-Hh IgG in rabbits after 3rd immunization. The anti-Hh IgG, isolated with caprylic acid precipitation method, was effective in neutralizing the venom lethality (potency=48 LD(50) per ml IgG) as well as its procoagulant, hemorrhagic and necrotic effects, indicating the possibility to produce the specific antivenom using the common immunization regime. Cross-reactivity studies using indirect ELISA showed that anti-Hh IgG cross-reacted extensively with several Asiatic crotalid venoms, particularly that of Calloselasma rhodostoma (73.6%), presumably due to the presence of venom antigens common to both snakes. Levels of immunological cross-reactivity were vastly reduced with double-sandwich ELISA. Further work demonstrated that the assay was able to distinguish and quantify venoms of H. hypnale, Daboia russelii and Echis carinatus sinhaleyus (three common local viperid) used to spike human sera at various concentrations. The assay hence may be a useful investigating tool for diagnosing biting species and studying the time course profile of venom concentrations in blood.     

Short report: Venomous snake bites in Japan

Few reliable data are available on the incidence of snake bites in developing and developed nations. Insufficient epidemiologic data have hindered the recognition of snake bite as an important public health issue. We verified statistics of snake bites (mamushi and habu bites) in Japan by using a currently available, nationally representative, hospital-based database. We identified 1,670 inpatients with snake bites from 404 hospitals during July 1-December 31 in 2007 and 2008. More than 60% were males, the average age was 60.1 years, and the in-hospital mortality rate was 0.2%. The incidence of mamushi bite, distributed between latitudes 30°N and 46°N, was estimated to be 1.67 bites/100,000/6 months. It is important to continue collecting all available data to monitor the trends of this life-threatening disease.     

Distinctive epidemiologic and clinical features of common krait (Bungarus caeruleus) bites in Sri Lanka

A prospective study was designed to define epidemiologic and clinical features of krait bites to improve diagnosis, management, and prevention. Among 762 cases of venomous snake bites admitted to 10 Sri Lankan hospitals in which the snake responsible was brought and identified, 88 (11.5%) were caused by common kraits (Bungarus caeruleus). Bites were: most frequent in September through November. Distinctive features of B. caeruleus bites (compared with bites by other species in parentheses) were bitten while sleeping on the ground, 100% (1%); indoors, 100% (49%); between 2300 and 0500 hours, 100% (3%). Only 13% of krait victims were bitten on their lower limbs (82%), only 9% had local swelling (in all cases mild) at the site of the bite (93%), 64% developed respiratory paralysis (2%), and 91% experienced (often severe) abdominal pain (10%). Case fatality was 6% (3%). This distinctive pattern of epidemiology and symptoms will aid clinical recognition (syndromic diagnosis) and prevention of krait bite envenoming.     

Haemolytic Uremic Syndrome a Hitherto Unreported Complication of Humpnosed Viper Envenomation

Merrem’s humpnosed viper bite is known to cause incoagulable blood, acute renal failure, acute respiratory distress syndrome, Raynaud’s phenomenon and gangrene of the distal limb. Venom-induced consumptive coagulopathy (VICC) is the commonest coagulopathy that occurs following snake envenomation which is characterised by prolonged clotting times. In a small proportion of patients with VICC, microangiopathy is also seen. The authors report a novel case of haemolytic uraemic syndrome following a merrem’s humpnosed viper bite, which highlights the need for comprehensive and serial haematological evaluation to detect the condition and initiate timely plasma exchange. The authors recommend screening of all victims of humpnosed viper bite for haemolytic uremic syndrome which might otherwise be overlooked and stress the need for further studies to see the role of haemolytic uremic syndrome following humpnosed viper bite.     

A clinical and epidemiological study on spider bites in Turkey

ObjectiveTo classify and characterize spider bites among inquiries to the National Poison Information Center (NPIC) between 1995 and 2004, in terms of the epidemiology and clinical symptomatology.MethodsClinical and epidemiological data were obtained from the NPIC's patient records. The following information was recorded for each spider bite: demographics, circumstances of the bite, and local and systemic effects.ResultsA total of 82 cases were reported. The accidents were mostly seen during August. The gender distribution was 59.76% male, 37.20% female, and 2.44% unknown and the 20–29 age group presented more spider bites. Most of the cases were in the Central Anatolia, Marmara, Mediterranean, and Black Sea regions. Local symptoms were observed in 60.87% of the cases, including local pain, edema, redness, itching, debris, burning, and numbness. Systemic symptoms were observed such as nausea, vomiting, abdominal pain, lethargy, anxiety, weakness, somnolence, dyspnea, hypertension, hypotension, and hyperthermia.ConclusionsIn conclusion, these findings emphasize the presence of medically important spider species in Turkey. All patients and especially pediatric patients should be admitted to the hospital. Identification of spider species may be considered a useful clinical and epidemiological tool in determining the incidence and risk of spider bites.     

Case Report: Saw-Scaled Viper Bites in Sri Lanka: Is It a Different Subspecies? Clinical Evidence from an Authenticated Case Series

The saw-scaled viper (SSV) (Echis carinatus) is considered to be a highly venomous snake in Sri Lanka despite any published clinical justification. Being a rarity, the clinical profile of SSV bites is not well established in Sri Lanka. We report a series of 48 (n-48) SSV bites from the Northern Province of Sri Lanka. The majority (65%) of victims had evidence of local envenoming at the site of the bite; however, 29% showed spontaneous bleeding and 71% had coagulopathy. There were no deaths in the series. The envenoming was mild in contrast to the mortality and significant morbidity associated with SSV bites in West Africa and some parts of India. These observations need to be further explored with laboratory studies to identify the venom components, study of morphological characteristics, and genetic profiling of the Sri Lankan SSV to see if it is different from the subspecies found elsewhere.     

A clinical study of viper bite poisoning

Thirty-one consecutive cases of snake bite were studied in the Benue Valley, Nigeria where carpet viper (Echis carinatus) bite constitutes a serious health problem. E. carinatus was responsible for 26 cases, the night adder (Causus maculatus) for three and the puff adder (Bitis arietans) for two. There were two fatalities, both late admissions following E. carinatus poisoning. One patient died after a subarachnoid haemorrhage and the other after tissue necrosis and the complications of a tightly applied tourniquet. Another fatality after E. carinatus bite was suspected in a patient who discharged himself from hospital after Behringwerke antivenom failed to control bleeding and coagulopathy. Other cases of Behringwerke antivenom's failure and of slow response to treatment confirmed the pressing need for a more effective Echis antivenom in West Africa. The enzyme-linked immunosorbent assay (ELISA) was used for diagnosing the biting species and was the only means of identifying the three cases bitten by C. maculatus and one case bitten by B. arietans.     

Acute Renal Failure Following the Saharan Horned Viper (Cerastes cerastes) Bite

Introduction: The Saharan horned viper (Cerastes cerastes) is a common snake in the sandy and rocky regions in the south of Morocco. Although nearly all snakes with medical relevance can induce acute renal failure (ARF), it's unusual except with bites by some viper species. ARF has very rarely been reported following Cerastes cerastes bite. Case Report: A 55-year-old Moroccan man was bitten on his right hand by a Saharan horned viper, Cerastes cerastes. He presented 24 hours later in a state of confusion, agitation and hypotension with marked swelling of his right hand. Investigations revealed evidence of disseminated intravascular coagulation (DIC) and rhabdomyolysis. The appropriate antivenom was not available. Despite adequate hydration, he developed acute renal failure necessitating prolonged hemodialysis. He subsequently improved and was discharged from the hospital after four weeks with normal renal function. Conclusion: Although uncommon, the bite of Cerastes cerastes can result in ARF due to DIC and rhabdomyolysis. The appropriate antivenom should be made available in areas where this snake is prevalent. Keywords: Acute Renal Failure; Antivenom; DIC; Cerastes Cerastes; Rhabdomyolysis; Snake Bite.     

Impact of snake bites and determinants of fatal outcomes in southeastern Nepal

Current available data on snake bites in Nepal are based solely on hospital statistics. This community-based study aimed at evaluating the impact of snake bites and determining the risk factors associated with a fatal outcome in southeastern Nepal. A total of 1,817 households, selected by a random proportionate sampling method, were visited by trained field workers in five villages. Extensive data from snake bite victims during the 14 previous months were recorded and analyzed. One hundred forty-three snake bites including 75 bites with signs of envenoming were reported (annual incidence = 1,162/100,000 and 604/100,000, respectively), resulting in 20 deaths (annual mortality rate = 162/100,000). Characteristics of krait bites such as bites occurring inside the house, while resting, and between midnight and 6:00 am were all factors associated with an increased risk of death, as were an initial consultation with a traditional healer, a long delay before transport, and a lack of available transport. An initial transfer to a specialized treatment center and transport by motorcycle were strong protective factors. Among the 123 survivors, wounds required dressing and surgery in 30 (24%) and 10 (8%) victims, respectively, the mean working incapacity period was 15 days, and the mean out-of-pocket expense was 69 U.S. dollars. Snake bite is a major but neglected public health problem in southeastern Nepal. Public health interventions should focus on improving victims' rapid access to anti-snake venom serum by promoting immediate and fast transport to adequate treatment centers, particularly for bites occurring at night.     

Randomized comparative trial of three monospecific antivenoms for bites by the Malayan pit viper (Calloselasma rhodostoma) in southern Thailand: clinical and laboratory correlations

Three monospecific antivenoms for Malayan pit viper (MPV) (Calloselasma rhodostoma) were compared in Southern Thailand, where this species is the most common cause of snake bite morbidity. Forty-six patients with proved MPV bites and incoagulable blood, indicating systemic envenoming, were randomly allocated for treatment with Thai Red Cross (TRC), Thai Government Pharmaceutical Organization (GPO), or Twyford Pharmaceutical monospecific antivenoms. Both GPO and Twyford antivenoms produced rapid and permanent restoration of blood coagulability, but TRC antivenom failed in 2/15 cases. Patients in the GPO group showed the greatest increase in plasma fibrinogen concentration during the first 24 hr and had fewer early anaphylactic reactions (6/15) compared with Twyford 8/16 and with TRC 13/15. Pyrogenic reactions occurred more frequently after TRC antivenom (8/15) than GPO (1/15) or Twyford (0/16). Patients requiring more than one dose of antivenom were identifiably more severely envenomed on admission. In an accompanying laboratory study the antivenoms were assessed in rodents using five WHO standard tests of neutralizing activity. Compared with the other two antivenoms TRC was significantly inferior in anti-lethal potency, GPO was superior in anti-hemorrhagic and anti-necrotic potency and Twyford was superior in anti-procoagulant and anti-defibrinogenating potency. The clinical efficacy of these antivenoms against local necrosis remains equivocal. GPO and Twyford antivenoms are recommended for the treatment of systemic envenoming by MPV in an initial dose of 5 ampoules.     

Serious envenomation after a snakebite by a Western bush viper (Atheris chlorechis) in the Netherlands: a case report

Venomous snakebites are a rarity in the Netherlands. In this report we describe the case of a 26-year-old male amateur snakekeeper who was bitten in his left index finger by a Western bush viper (Atheris chlorechis). His clinical condition deteriorated rapidly with acute renal failure and considerable blood loss due to coagulopathy. Antidote was not readily available and was finally supplied by a zoo in Antwerp, Belgium. One day after admission the blood loss diminished.     

Green pit viper (Trimeresurus albolabris and T. macrops) venom antigenaemia and kinetics in humans

Green pit viper bite is a common public health problem in Southeast Asia. Although most patients experience only local swelling, some may suffer from severe systemic bleeding that can be delayed. Venom antigenaemia was measured by enzyme-linked immunosorbent assay and correlated with clinical findings in 42 patients. Initial venom antigenaemia was not predictive enough for clinical uses. A kinetic study (n = 27) showed highest levels at presentation and, then, progressive decline. The average half-life was 27.5 h during the first three days and over 50 h on days 5-7 after bite. Two small subsets (7.4% each) showed persistently detectable venom on day 14 and a subsequent rise in venom antigenaemia. They were associated with prolonged thrombocytopaenia and coagulopathy, respectively. These data demonstrated the long half-life of the venom, suggesting that waiting for spontaneous resolution of coagulopathy is not preferable. In addition, the delayed venom disappearance, not the initial values, was correlated with haemostatic disorders.     

Epidemiological aspects of snake bites on a Liberian rubber plantation

During a one-year period 95 patients with a history of snake bite were admitted to the hospital of a Liberian rubber plantation. The population at risk included the field workers (tappers and slashers) with an incidence of 4.2 symptomatic snake bites per thousand per year. The incidence of symptomatic bites was 1.7 per thousand in the group of non-field employees and 0.4 per thousand per year in the group of non-employees. The temporary disability was between 3 and 5 days, and the loss of workings days due to snake bites was one day per 10,000 working days on the plantation. Among the 95 patients 27 did not show any symptoms of envenoming except occasional fang marks. 64 patients developed cytotoxic symptoms alone. In this group, the night adder (Causus maculatus) was the main responsible snake. 4 patients showed signs of systemic envenoming. Two were haematological and two were neurological in nature and caused by Bitis species and Naja species, respectively. No fatalities were noted. A definite maximum of snake bites was observed during October and November which corresponds to the transition from rainy to dry season.