The efficacy of antivenom in the treatment of bites by the Papuan taipan (Oxyuranus scutellatus canni)

A prospective series of 156 patients systemically envenomed following the bite of a Papuan taipan (Oxyuranus scutellatus canni) were studied. All patients were treated with appropriate antivenom and clinical course and outcome were compared. The proportion of patients requiring intubation was significantly smaller, and the time to resolution of neurotoxicity and discharge from hospital significantly shorter, in patients receiving antivenom no more than 4 h after the bite. No significant difference in outcome was demonstrated between patients receiving antivenom at various times after 4 h. No difference was demonstrated in the times to restoration of coagulability between the 2 groups. The only significant difference between a small number of patients given 2 vials of antivenom and patients given a single vial at the same time after envenoming was a marginally shorter duration of intubation in those who required it. The study suggests that, to achieve significant clinical benefit in Papuan taipan bite, antivenom must be given as early as possible.

Venom detection kits in the management of snakebite in Central province, Papua New Guinea

The bites of six species of venomous elapid snakes in Central Province Papua New Guinea produce similar clinical syndromes. Optimal management of envenomed patients involves the use of monospecific antivenom. In this study, Venom Detection Kits (VDKs) (CSL Diagnostics, Melbourne) were used to try to make a specific diagnosis in envenomed patients at their admission. VDKs detected venom in admission bite site swabs from 39 to 46 patients (85%). Thirty-eight of these patients were shown to have been bitten by taipans. In all cases where venom was detected by the VDK, this correlated with subsequent laboratory enzyme immunoassay results. Selective use of VDKs in Central Province could allow more widespread use of monospecific antivenoms and produce considerable financial savings.

The epidemiology of snake bite in Central Province and National Capital District, Papua New Guinea

Snake bite is an important medical problem in some areas of Papua New Guinea and appears to be most common in the Central Province and National Capital District. The overall incidence for Central Province is 215.5 per 100,000 population, but Kairuku subprovince has an incidence of 526 per 100,000, which is amongst the highest in the world. The clinical pattern of envenoming also varies within the Province, suggesting that different species of snake may be responsible for bites in different areas. Most envenomed patients are bitten during daylight on the lower limb and are rarely able to describe the snake. The mortality rate in Central Province is 7.9 per 100,000; most patients die from ventilatory failure due to severe neurotoxicity. Mortality might be reduced by increased use of compression bandaging as a first aid measure, earlier treatment with antivenom and earlier referral to hospital.

King cobra (Ophiophagus hannah) bites in Myanmar: venom antigen levels and development of venom antibodies

Venom, venom IgG and IgM antibody and total serum IgG levels following king cobra bites in two reptile handlers were measured by enzyme immunoassay. The patient in case 1 received antivenom while the patient in case 2 did not. Case 1 made a complete recovery following the bite and produced a high titre short-lived antibody. Venom antigen was not detected in the sample taken 11 hr after antivenom. Case 2 had experienced two recent minor king cobra bites and had received traditional immunization 4 weeks before the accident reported here. He had developed only local swelling and suffered no neurological symptoms. Venom antigen measured at 1.45 hr after the bite was 132 ng/ml; this rapidly fell to 45 ng/ml over the next 30 min, and was no longer detectable 14 hr after the bite. The pattern of venom IgG and IgM antibody responses in both cases was comparable, except that in case 2 the venom IgG peak was maintained for 13 days, compared with 1 day in case 1; in case 2 it subsequently fell to low levels 8 weeks after the bite. Venom IgM appeared 1 day after the bite, peaked at day 7-9, rapidly tailed off on day 12-16 and was then undetectable from day 20 onwards in both. Total IgG level remained within normal limits in both. It is possible that previous bites and recent immunization contributed to the boosting of the venom IgG response in case 2.

Coagulopathy following bites by the Papuan taipan (Oxyuranus scutellatus canni)

The mechanisms of haemostatic failure were studied in 87 patients bitten by the Papuan taipan (Oxyuranus scutellatus canni). Eighty (92%) had evidence of a coagulopathy on laboratory testing; 36 (41.4%) developed spontaneous systemic bleeding, although this was rarely of clinical significance. Coagulation assays in 48 completely defibrinated patients showed marked reductions in factors V and VIII and reductions in factors II, IX, XI, XII and XIIIA. There was a reduction in plasminogen and alpha 2-antiplasmin levels and both total and cross-linked fibrin(ogen) degradation products (FDP) levels were elevated. The mean platelet count was initially decreased and fell further during admission. Similar but less severe changes were seen in patients who were mildly defibrinated. Following treatment with antivenom, fibrinogen levels rose rapidly and coagulability was restored within 6-12 h in 93% of patients. These abnormalities may be primarily attributable to the prothrombin activator present in taipan venom, but it is likely that other uncharacterized venom components contributed.

Development of alpha-neurotoxin antibodies in patients envenomed by the monocellate Thai cobra (Naja kaouthia)

Serum samples from 50 patients envenomed by the Thai cobra (Naja kaouthia) were tested by enzyme immune assay for the presence of antibodies against the principal neurotoxin. Samples were taken between 1 month and 19 years after the bite. Only 16% (8/50) of the samples were positive for antibodies against neurotoxin, while 76% (38/50) were positive for antibodies against whole venom. There was no clear correlation between the presence of antibodies against neurotoxin and clinical features.

Imported falciparum malaria in British troops returning from Kenya

The objective of this study was to report on a breakthrough of Plasmodium falciparum infection following a military exercise in central Kenya and the treatment regimens used. A series of case reports are presented from the three UK hospitals involved. Among 150 British soldiers who had been on exercises for five weeks in central Kenya, taking proguanil/chloroquine anti-malarial prophylaxis, seven developed symptomatic falciparum malaria. Initial symptoms, which started between 2 and 10 days before their return to England, included faintness, sweating, shivering, diarrhoea, headache and myalgia. Diagnosis was delayed from between 5 and 13 days after the first symptom. One patient was severely ill with 50% parasitaemia: he required intensive care, exchange blood transfusion and haemofiltration for acute renal failure. Compliance with chemoprophylaxis was not measured and anti-mosquito measures were not generally practised. However, British Army policy was amended in June 1993 so that mefloquine will be used in future rather than proguanil/chloroquine. It was concluded therefore that even in an educated and motivated population simple preventive measures are not observed. Chemoprophylactic compliance could be improved by changing to a simpler regime. Falciparum malaria is a medical emergency that requires urgent admission for confirmation of diagnosis, supportive and curative treatment. Its presence should be suspected in any ill traveller.

Analysis of referral letters to assess the management of poisonous snake bite in rural Papua New Guinea

A prospective series of patients envenomed after snake bite was seen at Port Moresby General Hospital (PMGH), Papua New Guinea, between January 1991 and December 1992. Referral letters were received with 60 of the patients who had been initially seen at a health centre. These letters were analysed in conjunction with our own clinical observations. The importance of non-clotting blood and local lymphadenopathy as early signs of systemic poisoning did not appear to be universally recognized by staff in health centres. In some cases, no attempt was made to transfer the patient to hospital until signs of neurotoxicity were established with potentially dangerous delay. Analysis of both hospital and health centre records suggests that the majority of deaths which occurred in Central Province, Papua New Guinea, during the period of the study were due to delay in transfer to hospital. We suggest that all patients with unequivocal signs of envenoming in Central Province, Papua New Guinea, should be transferred to PMGH as soon as possible. Antivenom should also be given as soon as possible, but this does not remove the need for immediate transfer.

Reliability of the simple 20 minute whole blood clotting test (WBCT20) as an indicator of low plasma fibrinogen concentration in patients envenomed by Bothrops snakes. Butantan Institute Antivenom Study Group

Reliability of the simple 20 minute whole blood clotting test (WBCT20) as an indicator of low plasma fibrinogen concentration in patients envenomed by Bothrops snakes. Toxicon 32, 1045-1050, 1994.--A simple whole blood clotting test (WBCT20) was assessed for its efficacy in determination of severe defibrinogenation in patients envenomed by Bothrops snakes in Brazil. There was a close relationship between the results of the WBCT20 and plasma fibrinogen levels in 69 moderately envenomed patients. The advantage of the WBCT20 over estimation of plasma fibrinogen concentrations in patients is that it is a simpler, faster and more reliable test. It is also of use in assessing the effectiveness of antivenom therapy in relation to the restoration of blood coagulability.

Biological properties of the venom of the Papuan black snake (Pseudechis papuanus): presence of a phospholipase A2 platelet inhibitor

The whole venom of Pseudechis papuanus, in addition to its anticoagulant activity, powerfully inhibited platelet aggregation induced by ADP, adrenaline, collagen, ristocetin and thrombin. High levels of phospholipase A2 (PLA2) activity were detected. A mild procoagulant activity was also observed. Following exposure of platelets to P. papuanus venom, platelet factor 3 (procoagulant platelet phospholipid) showed decreased cofactor activity in factor X activation by Russell's viper, venom suggesting that the venom PLA2 plays a major role in the inhibition of the coagulation mechanism. In vivo rodent assays confirmed the inhibitory effect on platelets and the haemorrhagic and neurotoxic activities. It is possible that PLA2 is responsible for anticoagulation and that this, combined with the effect on platelet aggregation, a mild procoagulant and a moderately potent haemorrhagin, is responsible for the haemorrhagic diathesis observed in systemically envenomed patients. Polyvalent (Australia-Papua New Guinea) Commonwealth Serum Laboratories antivenom, currently used for clinical treatment of snakebite in Papua New Guinea, proved highly effective against P. papuanus venom in rodent and in vitro assays, despite the absence of this particular venom from the immunising mixture.

Neurotoxicity, haemostatic disturbances and haemolytic anaemia after a bite by a Tunisian saw-scaled or carpet viper (Echis 'pyramidum'-complex): failure of antivenom treatment

A young man in Germany was bitten by a large captive saw-scaled viper (Echis 'pyramidum'-complex) of Tunisian origin. During the first few hours after the bite he developed evidence of disseminated intravascular coagulation and fibrinolysis, and bled spontaneously. Despite being given a total of 310 ml of three different Echis-specific antivenoms (together with large amounts of fresh frozen plasma and concentrated clotting factors), venom antigenaemia (measured by enzyme immunoassay) and coagulopathy persisted for more than 10 days, and he developed a haemolytic anaemia and mild renal dysfunction. Transient bilateral ptosis was attributed to envenoming. The venom of the snake responsible for the bite was immunologically distinct from that of Nigerian E. ocellatus and was clearly not neutralised by the three monospecific antivenoms which had been administered. This case is another illustration of the geographical variation in snake venoms and the need for pooling venoms from snakes from different parts of the geographical range in the preparation of antivenoms. Envenoming by North African Echis species may not be reversible by available antivenoms.

Neurotoxicity and haemostatic disturbances in patients envenomed by the Papuan black snake (Pseudechis papuanus)

Among 335 patients presenting with snakebites in Central Province, Papua New Guinea, nine were proved by enzyme immunoassay to have been bitten by Papuan black snakes (Pseudechis papuanus). Seven showed clinical evidence of envenoming. Early symptoms included vomiting and tender local lymph nodes. Five patients had neurotoxic signs and one required mechanical ventilation. Spontaneous systemic bleeding occurred in two patients. Coagulation studies in four patients showed thrombocytopenia, prolongation of prothrombin time, mild defibrination and depletion of other clotting factors with elevated fibrin(ogen) degradation products and other evidence of fibrinolysis. One patient developed mild renal dysfunction. There was no evidence of intravascular haemolysis or rhabdomyolysis. These clinical observations, which do not distinguish victims of P. papuanus from those of taipans (Oxyuranus scutellatus canni), suggest that the venom contains neurotoxic, haemorrhagic and mild procoagulant activities. Only two other cases of proven envenoming by this species have been reported. There appears to have been a decline in the abundance of this species, and hence its medical importance, over the last 25 years.

Severe and fatal mass attacks by 'killer' bees (Africanized honey bees--Apis mellifera scutellata) in Brazil: clinicopathological studies with measurement of serum venom concentrations

In São Paulo State, Brazil, five males, aged between 8 and 64 years, were attacked by 'Africanized' honey bees (Apis mellifera scutellata). The estimated number of stings received by each patient ranged from > 200 to > 1000. All five were transferred to intensive care units in São Paulo City. Clinical features included intravascular haemolysis, respiratory distress with ARDS, hepatic dysfunction, rhabdomyolysis (with myoglobinaemia and myoglobinuria), hypertension and myocardial damage (perhaps explained by release of endogenous catecholamines by venom phospholipase A2 and mellitin), shock, coma, acute renal failure and bleeding. Laboratory findings included gross neutrophil leucocytosis, elevated serum enzymes [AST, ALT, LDH, CPK (predominantly CPK-MM)] and creatinine. Clotting times were slightly prolonged. Despite treatment with antihistamines, corticosteroids, bronchodilators, vasodilators, bicarbonate, mannitol and mechanical ventilation, three of the patients died between 22 and 71 h after the attacks, with histopathological features of ARDS, hepatocellular necrosis, acute tubular necrosis, focal subendocardial necrosis and disseminated intravascular coagulation. Whole bee venom and phospholipase A2 (PLA2) antigen concentrations were measured in serum and urine for the first time, using enzyme immunoassay. High venom and PLA2 concentrations were detected in serum and urine for more than 50 h after the stings in two fatal cases, in one of which the total circulating unbound whole venom was estimated at 27 mg, one hour after the attack. An antivenom should be developed to treat the increasing numbers of victims of mass attacks by Africanized 'killer' bees in USA, Middle and South America.

Haemostatic dysfunction and acute renal failure following envenoming by Merrem's hump-nosed viper (Hypnale hypnale) in Sri Lanka: first authenticated case

A five years old boy was bitten by a Merrem's hump-nosed viper (Hypnale hypnale) in Central Province, Sri Lanka. He developed local swelling, incoagulable blood, thrombocytopenia, bleeding into the gastrointestinal tract, and acute renal failure. Treatment with Serum Institute of Indian polyspecific antivenom (specific for venoms of cobra, common krait, Russell's viper and saw-scaled viper) had no effect on the coagulopathy, which persisted for more than a week. The boy recovered after 27 d in hospital, during which he was treated with peritoneal dialysis for renal failure. Laboratory studies demonstrated that the venom of H. hypnale was procoagulant, fibrinolytic and aggregated platelets. This first authenticated case of life-threatening acute renal failure and haemostatic disturbances caused by H. hypnale, a species responsible for 27% of snake bites in Sri Lanka, demonstrates the need for a new antivenom with specific activity against the venom of this species.

Venomous bites and stings in the tropical world

Snakes of the families Viperidae and Elapidae are responsible for the high incidence of morbidity and mortality after snake bites in countries of West Africa, the Indian subcontinent, South-East Asia, New Guinea and Latin America. Envenoming can cause local effects, notably tissue necrosis; and systemic effects, including paralysis, haemostatic disturbances, shock, increased capillary permeability, myocardial damage, rhabdomyolysis and acute renal failure. Specific hyperimmune serum (antivenom) is the mainstay of medical treatment for severe envenoming. Ancillary treatments such as assisted ventilation, repletion of circulating volume, renal dialysis and surgical debridement of necrotic tissues are needed in some cases. Scorpion stings are a common medical problem in middle and southern America, North Africa and the Middle East. Vasodilator drugs are important to counter the effects of massive catecholamine release. Bites by spiders and stings by hymenoptera and marine animals are responsible for deaths and morbidity in some tropical countries.

Neurotoxic envenoming by the Sri Lankan krait (Bungarus ceylonicus) complicated by traditional treatment and a reaction to antivenom

A 30 year old woman bitten by a large Sri Lankan krait (Bungarus ceylonicus) developed progressive paralytic symptoms within one hour of the bite. After seeking traditional treatment her condition deteriorated and when she arrived at hospital 6 h after the bite she was drowsy, with bilateral ptosis and signs of aspiration pneumonia (a complication of traditional treatment). She developed an anaphylactic reaction after antivenom treatment and, despite treatment, had a cardio-respiratory arrest. She was resuscitated and mechanically ventilated, but remained deeply unconscious until her death 90 h after the bite. B. ceylonicus is endemic in Sri Lanka, is common in some areas, and could be mistaken for the common krait (B. caeruleus). It is doubtful whether any existing antivenom is effective against its venom.

Renal ischaemia, transient glomerular leak and acute renal tubular damage in patients envenomed by Russell's vipers (Daboia russelii siamensis) in Myanmar

Fifty-two patients who had been bitten by Russell's vipers in Myanmar developed acute renal failure (serum creatinine exceeding 1.3 mg/dL). Thirty-four of them (65%) became oliguric, but the other 18 (35%) maintained a urine output of more than 400 mL/24 h. In oliguric patients, gastrointestinal haemorrhages, renal angle tenderness and conjunctival oedema occurred more commonly, and peak serum creatinine, blood urea nitrogen and the fractional excretion of sodium were significantly higher (P < 0.01) than in non-oliguric patients, indicating a greater degree of renal damage. Urinary concentrations of beta 2 microglobulin and retinol binding protein were raised in most of the patients indicating failure of proximal tubular reabsorption of these proteins, while high urinary N-acetyl glucosaminidase concentrations were consistent with renal tubular damage. Plasma concentrations of active renin were very high, suggesting that renal ischaemia, associated with activation of the renin-angiotensin system, was involved in the development of renal dysfunction.

Action of snake venom components on the haemostatic system

Among the components in snake venom are a number which have profound effects (either stimulatory or inhibitory) on haemostatic mechanisms, including coagulation, fibrinolysis, platelet function and vascular integrity. As a consequence, human victims of snakebite may suffer severe and sometimes fatal haemorrhagic and/or thrombotic sequelae. Many of these venom components have been isolated and their precise mechanisms of action established. Apart from direct fibrinolysins, procoagulants predominate, most of these exerting their effect late in the clotting cascade, activating factor X or prothrombin or directly converting fibrinogen to fibrin. Some of the procoagulants are, or have the potential to be, used as therapeutic agents. Some venom components have been put to use as laboratory reagents for diagnostic purposes or for characterising molecular defects of haemostasis, although because they often have unphysiological actions, results must be interpreted with caution. These and other useful constituents e.g. protein C activator and platelet aggregating agents are discussed.

Venomous bites and stings

Travellers to tropical countries are often extremely concerned about the risk of bites and stings by venomous animals. This fear prompts many enquiries, usually at the last moment before departure, about the possibility of carrying first aid kits and antivenoms. In fact, these accidents are extremely rare because most travellers wear shoes and are far less exposed to venomous animals than indigenous peoples for whom bites and stings may be important causes of death or morbidity.

Hypoglycaemia and counterregulatory hormone responses in severe falciparum malaria: treatment with Sandostatin

The mechanism and response to treatment of severe life-threatening hypoglycaemia (plasma glucose 1.15 +/- 0.73 mM/l [+/- SD]) was studied in eight Thai patients with falciparum malaria. Plasma insulin concentrations were inappropriately high (range 1.0-21.8 mU/l), lactic acidosis was common (arterial blood lactic acid concentration 1.44-17.8 mM/l), but the glucose counterregulatory response, indicated by plasma cortisol, growth hormone, catecholamines and glucagon concentrations, was intact. Hyperinsulinaemia was successfully treated in five patients by a continuous intravenous infusion of the long-acting somatostatin analogue Sandostatin (SMS 201-995), 50 micrograms/h. In volunteer studies a single intramuscular injection of Sandostatin (100 micrograms) suppressed quinine-induced hyperinsulinaemia within 15 min; this effect was maintained for 6 h. These results suggest that Sandostatin may be a safe and effective way of correcting the hyperinsulinaemic hypoglycaemia complicating quinine treatment of falciparum malaria. This treatment could be particularly useful in fluid-overloaded patients with recurrent hypoglycaemia despite dextrose infusions.

Brucellosis: imported and laboratory-acquired cases, and an overview of treatment trials

Following the successful eradication of Brucella abortus infection in cattle, human brucellosis in England and Wales has become an uncommon imported disease. Culture of the organism presents a major laboratory hazard, and difficulties in identification may occur using a biochemical test-strip method. An overview of recent treatment trials of brucellosis indicates that regimens combining streptomycin and doxycycline are associated with a higher success rate (judged by the frequency of treatment failure and relapse following therapy) than combinations of rifampicin and doxycycline.

Accidental envenoming by a Gaboon viper (Bitis gabonica): the haemostatic disturbances observed and investigation of in vitro haemostatic properties of whole venom

We report the successful treatment of envenoming by the Gaboon viper (Bitis gabonica) and include results of in vitro investigations of the haemostatic properties of the whole venom. The patient was admitted to casualty soon after the bite with chest tightness, dizziness, nausea and swelling at the site of the bite and was treated immediately with polyspecific antivenom, hydrocortisone, chlorpheniramine and antibiotics. Results of haemostatic investigations were essentially normal on admission but on day 3 the thrombin time became prolonged and was associated with significant hypofibrinogenaemia and elevated D-dimers. Factors V and VIII, antithrombin III and protein C levels and platelet number were not significantly reduced. The haemostatic disturbances persisted for more than 24 h despite treatment with blood products (16 units of cryoprecipitate, 2 units of fresh frozen plasma and 6 units of platelet concentrate). Resolution of the abnormalities occurred only after administration of a further dose of antivenom. The period of hypofibrinogenaemia occurred at a time when venom antigen was undetectable in plasma by enzyme-linked immunosorbent assay. Studies in vitro with whole venom and a panel of amidolytic substrates commonly employed for measurement of haemostatic proteins revealed significant activity of venom with substrates sensitive to kallikrein and plasmin. The venom inhibited washed platelet aggregation induced by collagen, thrombin, arachidonic acid and the calcium ionophore A23187 in a dose-dependent manner.

Use of enzyme immunoassays to compare the effect and assess the dosage regimens of three Brazilian Bothrops antivenoms. The Butantan Institute Antivenom Study Group (BIASG)

The effect of the three main Brazilian polyspecific antivenoms on venom clearance was assessed in 118 moderately envenomed victims of bites by Bothrops species (mainly B. jararaca) in Sao Paulo State, Brazil. Serum samples taken from patients at intervals during their stay in the hospital and at followup approximately four weeks later were tested by enzyme immunoassay for the presence of whole venom and therapeutic antivenom. Results indicated that in patients treated with the standard regimen of either four (40 ml) or eight (80 ml) ampules of each antivenom, venom was cleared from the circulation within four days of antivenom administration. However, high concentrations of antivenom persisted for approximately 10 days and remained detectable until 30-50 days after administration. This suggests that patients may be being treated with excessive amounts of antivenom in Brazil. This practice increases the national cost of antivenom therapy and may contribute to the high frequency of antivenom reactions. Clinically, there was no obvious difference in the efficacy between the three antivenoms.

Comparison of the potency of three Brazilian Bothrops antivenoms using in vivo rodent and in vitro assays. BIASG (Butantan Institute Antivenom Study Group)

Three Brazilian polyspecific Bothrops antivenoms were compared using standard W.H.O. rodent in vivo and in vitro assays of their ability to neutralize the principal venom activities of pooled whole Bothrops jararaca venom. On a volume basis, the antivenoms were equally effective in neutralizing lethal activity in mice, and there were only minor differences in their ability to neutralize venom-induced haemorrhage, necrosis and procoagulant activity. Antivenom efficacy in neutralizing defibrinogenation varied. However, when equal amounts of antivenom IgG were compared, it was found that the FUNED antivenom best neutralized lethality, haemorrhage, necrosis and fibrinogen clotting activity. Vital Brazil and FUNED antivenoms were equally effective in neutralizing plasma coagulant activity but Vital Brazil antivenom was the more effective in neutralizing defibrinogenation.

Cerebral malaria

Cerebral malaria is the most important manifestation of severe Plasmodium falciparum infection. The clinical picture in South East Asian adults differs from that in African children. The children are more likely to have abnormal brain stem reflexes, signs suggestive of cerebral herniation, and raised CSF opening pressure, and to suffer persistent neurological sequelae. The mortality remains high at about 20%. The diagnosis must be considered in all patients with fever and impaired consciousness who may have been exposed to the infection. The pathophysiology of cerebral malaria may involve mechanical obstruction of the cerebral circulation by parasitized erythrocytes which have adhered to the vascular endothelium. Cytokines such as tumor necrosis factor may also contribute. The most important element of treatment is early, optimal chemotherapy with quinine, but artemisinine derivatives may prove even more effective.

Prophylactic phenobarbitone in young children with severe falciparum malaria: pharmacokinetics and clinical effects

1. A method is described for the measurement of phenobarbitone (PB) by reversed phase high performance liquid chromatography (h.p.l.c.) from small samples of whole blood dried onto filter paper strips. 2. The disposition of PB given prophylactically to young children with severe malaria on parenteral quinine is contrasted with that in aparasitaemic Kenyan children on no antimalarial drugs. There were no differences in the disposition of PB between the two groups. 3. Peak blood PB concentrations were equal to or greater than 15 mg l-1 in 27% of the patients on quinine and 23% of those not on quinine; a concentration of 10 mg l-1 was achieved or exceeded by 100% and 92% of each group, respectively, and was maintained for 39 +/- 24 h (mean +/- s.d.), and 33 +/- 21 h, respectively. 4. In an open, dose-finding study, the progress of young children with cerebral malaria given prophylactic PB (10 mg kg-1), was contrasted with that of controls given no seizure prophylaxis. 5. The drug had no apparent effect on depth or duration of coma, but neither was the incidence of seizures reduced. 6. A controlled trial of prophylactic PB in young children with cerebral malaria is needed, but a larger dose than 10 mg kg-1 should be studied.

The disposition of oral and intramuscular pyrimethamine/sulphadoxine in Kenyan children with high parasitaemia but clinically non-severe falciparum malaria

1. H.p.l.c. methods are described for the measurement of pyrimethamine and sulphadoxine in small volumes of plasma dried on filter paper strips. 2. Pyrimethamine/sulphadoxine (Fansidar, Hoffman LaRoche) was given by mouth and by intramuscular injection to children with uncomplicated falciparum malaria but with high parasitaemia (n = 8 for both routes; pyrimethamine 1.25 mg kg-1, sulphadoxine 25 mg kg-1). 3. Plasma concentrations of pyrimethamine and sulphadoxine associated with synergistic effects against pyrimethamine-resistant strains of Plasmodium falciparum in vitro were achieved within 1 h of administration and were maintained beyond the end of sampling. 4. After both oral and parenteral administration the plasma concentrations of both compounds were lower than those predicted by data from healthy subjects. 5. Areas under the plasma concentration-time curves of sulphadoxine after oral and i.m. administration did not differ significantly, although maximum plasma drug concentrations were higher after the i.m. route (P = 0.03). 6. The AUC values of pyrimethamine did not differ significantly between the two routes of administration. However, after i.m. administration AUC(0,24 h) values were smaller (P = 0.03), and the time to maximum plasma drug concentration (tmax) was longer (P = 0.004) than when the drug was given orally.

Rediscovery and redefinition of Malcolm Smith's Trimeresurus kanburiensis in Thailand, with a report of envenoming

Three specimens of an apparently rare pit viper, Trimeresurus kanburiensis, previously known only from the holotype collected in 1928, were found near Kanchanaburi in western Thailand. One of the snakes had bitten a young woman on the foot. She experienced severe local pain, swelling that involved the whole of the bitten limb and beyond, local bruising, recurrent shock, peripheral leucocytosis and a mild coagulopathy, but she recovered despite the lack of specific treatment. The severity of envenoming augurs ill for a young or debilitated patient bitten by this species. During the last 20 years, the name T. kanburiensis has been used incorrectly for the medically more important species, T. purpureomaculatus. Conversely, the name T. purpureomaculatus has been misapplied to specimens of a species of viper from southern Thailand which we consider very similar to T. kanburiensis, but for which a new specific name, 'T. venustus', has been suggested recently. The rediscovery and redefinition of T. kanburiensis should prevent further confusion.

A national hospital-based survey of snakes responsible for bites in Thailand

Snakes which had been killed and brought to hospital with the patients they had bitten were collected in 80 district and provincial hospitals throughout 67 provinces in Thailand in order to establish the geographical distribution and relative medical importance of the venomous species. Of the 1631 snakes collected, 1145 were venomous: Malayan pit vipers (Calloselasma rhodostoma), green pit vipers (Trimeresurus albolabris) and Russell's vipers (Daboia russelii) were the most numerous, while T. albolabris, C. rhodostoma and spitting cobras ('Naja atra') were the most widely distributed. In 22 cases, non-venomous species were mistaken for venomous ones and antivenom was used unnecessarily. The Malayan krait (Bungarus candidus) was confused with B. fasciatus in 5 cases and B. fasciatus antivenom was used inappropriately. The study extended the known ranges of most of the medically-important venomous species in Thailand. Correct identification of venomous snakes is especially important in Thailand because the locally-produced antivenoms are monospecific. The technique of hospital-based collection, labelling and preservation of dead snakes brought by bitten patients is recommended when rapid assessment of a country's medically important herpetofauna is required.

Quinine treatment of severe falciparum malaria in African children: a randomized comparison of three regimens

The pharmacokinetics and effectiveness of three dosage regimens of quinine were studied in a group of 59 children with severe malaria. The children were randomized to receive high-dose intravenous or intramuscular quinine (20 mg salt/kg loading, then 10 mg salt/kg every 12 hr), or low-dose intravenous quinine (10 mg salt/kg loading, then 5 mg salt/kg every 12 hr). In the group receiving the high-dose intravenous regimen, mean high and low quinine concentrations were consistently greater than 10 and 6.5 mg/l, respectively. Peak concentrations as well as the time required to achieve them were similar in the intramuscular and high-dose intravenous groups. The low-dose intravenous quinine regimen resulted in mean peak concentrations greater than 6 mg/l and mean low concentrations greater than 3.5 mg/l. All blood concentrations exceeded the 99% in vitro inhibitory concentration (EC99) of 0.89 mg/l or less of quinine for 60 isolates of Plasmodium falciparum, which were taken from children with malaria during the same period. Judged by a number of clinical criteria, the response was better in patients receiving the high-dose than the low-dose intravenous regimen. The time taken to clear parasites with both the high-dose intravenous and intramuscular regimens were significantly shorter than those obtained in the low-dose group. We have also shown for the first time that the rate of parasite clearance can be directly related to the area under the quinine concentration versus time curve. This applied to all three quinine regimens (r = 0.4252, P less than 0.02; n less than or equal to 35). Five patients, two on the low-dose regimen, two on the intramuscular regimen, and one on the high-dose regimen, developed hypoglycemia after admission, but in these cases, insulin concentrations were correspondingly low. No significant quinine toxicity was observed in any of the cases. The high-dose intravenous quinine regimen described here may be optimal for treatment of severe falciparum malaria in areas of chloroquine resistance in Africa. Our data provide no justification for reducing the dose of quinine in the treatment of severe malaria in Africa. The intramuscular regimen could provide a satisfactory alternative in areas where intravenous administration might be delayed or is impossible.

Bites by Russell's vipers (Daboia russelii siamensis) in Myanmar: effect of the snake's length and recent feeding on venom antigenaemia and severity of envenoming

An improved enzyme immunoassay technique (EIA) was used in the diagnosis of 311 suspected Russell's viper bite cases in Myanmar [Burma], 181 of whom (58%) had systemic envenoming. Russell's viper venom was detected in the sera of 175 (56.3%), cobra or green pit viper venoms in 4 (1.3%), and no venom in the remaining 132 (42.4). Among 175 of these patients who failed to bring the dead snake, EIA achieved a specific diagnosis of Russell's viper envenoming in 101 (58%). The serum venom antigen concentration was higher in patients with systemic envenoming than in those with local or no envenoming and it increased with the development of coagulopathy. Stomach contents were examined in 101 Russell's vipers responsible for bites. The presence of prey, usually a rodent, in the snake's stomach, indicating that it had eaten recently, did not influence the severity of envenoming, the initial venom level, or the percentage circumference increase and the extent of local swelling in the bitten limb. One hundred and fifty-five Russell's vipers responsible for bites showed a bimodal distribution of total lengths. The smaller snakes had probably been born that year. Longer snakes were responsible for more severe envenoming, a shorter interval between the bite and the detection of incoagulable blood, and more extensive local swelling with a greater percentage circumference increase of the bitten limb; but their bites were not associated with higher initial venom antigenaemia or a greater risk of developing acute renal failure.

Bites by the king cobra (Ophiophagus hannah) in Myanmar: successful treatment of severe neurotoxic envenoming

Three patients bitten by the world's largest species of venomous snake, the king cobra (Ophiophagus hannah), were observed in Myanmar (Burma). All three were involved in the famous snake dance in Yangon (Rangoon) Zoological Gardens. One patient showed no signs of envenoming despite a sustained bite, another developed only signs of local envenoming, but in a third there was severe neurotoxic envenoming requiring mechanical ventilation for 64 1/2 hours, episodes of hypotension and massive swelling of the bitten limb. This patient showed some signs of recovery before delayed treatment with specific antivenom. It is possible that all three patients had some immunity to king cobra venom resulting from traditional 'immunization' achieved by scratching venom into the skin. The literature on king cobra bites is reviewed and recommendations given for antivenom and ancillary treatments.

Development of renal function abnormalities following bites by Russell's vipers (Daboia russelii siamensis) in Myanmar

Renal function was monitored in 24 patients with systemic envenoming following proven Russell's viper bite. In all patients, blood clotted within 20 min on admission. In 15 cases severe defibrination (systemic envenoming) developed during the next 3-5 d. None of the patients received antivenom before admission but enzyme-refined monospecific antivenom was given to those who developed signs of systemic envenoming. Specific antigen was detected by enzyme immuno-assay in all 21 subjects tested. Nine patients whose renal function remained normal did not develop systemic envenoming, and recovered without any treatment even though venom antigen was detectable in their serum. Ten patients developed mild renal dysfunction and systemic envenoming, but recovered after treatment with antivenom alone. The remaining 5 patients, all of whom were oliguric from admission, developed acute renal failure despite treatment with antivenom, but some recovered after peritoneal dialysis. Serum venom antigen levels were high in the last 2 groups, but there was some overlap. Albuminuria, found only in patients who became systemically envenomed, was associated with high fractional sodium excretion in those who developed acute oliguric renal failure. Albuminuria may appear before a gross clotting defect is detectable. It is an indication for antivenom and spot measurements might prove a useful early predictor of outcome.

Intracranial pressure in African children with cerebral malaria

Opening lumbar cerebrospinal fluid (CSF) pressure was measured with a paediatric spinal fluid manometer in 26 of 61 Kenyan children (mean age 39 months) with cerebral malaria. In all cases pressure was above normal (mean [SD]22.6 [7.4] cm CSF, range 10.5-36). Clinical features of our patients suggest that intracranial hypertension is important in the pathogenesis of cerebral malaria in children, especially as a cause of death. We suggest that raised intracranial pressure is secondary to increased cerebral blood volume. Lowering intracranial pressure may significantly reduce the mortality and morbidity of cerebral malaria. The potential risks and benefits of lumbar puncture should be considered carefully in patients with suspected cerebral malaria.

The Jarisch-Herxheimer reaction in leptospirosis: possible pathogenesis and review

The importance of treating leptospirosis with penicillin is emphasized by two case reports and a review documenting the occurrence of the Jarisch-Herxheimer reaction (JHR) in patients with this bacterial infection. The JHR is significant both as a cause of morbidity and mortality and as an indication of the therapeutic efficacy of penicillin. The possible etiology of the JHR is discussed, and comparisons with the changes occurring in septic shock are made; a study of either condition facilitates the understanding of the other. Tumor necrosis factor is hypothesized to play a key role in both. Current treatment of the JHR consists of general clinical support. Specific measures such as oxpentifylline therapy may play a role in the future.

Coagulopathy and haemorrhage in human victims of Bothrops jararaca envenoming in Brazil

Thirty-four patients envenomed by Bothrops jararaca in Brazil were studied. Of these, 20 (59%) had incoagulable blood associated with local and/or systemic bleeding and 10 of the 20 were thrombocytopenic. Among 14 patients with coagulable blood, 6 (43%) had bleeding symptoms and 3 (21%) were thrombocytopenic. High levels of von Willebrand factor (vWF), plasminogen activator inhibitor type 1 (PAI-1) and tissue type plasminogen activator (t-PA) antigens were also recorded in some patients with systemic bleeding with or without incoagulable blood. These substances may have been released from endothelial cells. Admission serum venom antigen levels were similar in both groups. The study indicated that systemic haemorrhage may occur in patients with coagulable blood and thrombocytopenia and that coagulopathy is not therefore the primary cause of haemorrhage.

Neurotoxic envenoming by an immigrant spider (Steatoda nobilis) in southern England

A young woman was bitten on the shoulder by a female Steatoda nobilis spider, in Worthing on the south coast of England. She noticed intense radiating pain, local sweating (indicating parasympathetic stimulation) and feverishness. This immigrant species from the Canary Islands has established itself along the south coast of England in recent years. Like the related Mediterranean species S. paykulliana, S. nobilis may be of medical importance and deserves further study.

Bacteriological studies of the venom and mouth cavities of wild Malayan pit vipers (Calloselasma rhodostoma) in southern Thailand

Venom and oropharyngeal swabs from freshly captured Malayan pit vipers (Calloselasma rhodostoma) in southern Thailand and captive specimens in England were cultured aerobically and anaerobically to identify the bacterial flora which might contaminate wounds inflicted by bites of this species. The snakes' mouths contained a wider range of organisms than their venoms, especially gut-related Gram-negative rods such as Enterobacter and Pseudomonas species and some staphylococci and clostridia. There were fewer positive cultures from captive snakes. C. rhodostoma venom inhibited the growth of group A streptococci and, to a lesser extent, that of Staphylococcus aureus and Clostridium perfringens but not that of 2 Gram-negative organisms. Secondary bacterial infection is an important complication of snake bite, especially of necrotic wounds. A combination of gentamicin with benzyl penicillin would have prevented infection with, or treated, most of the bacteria isolated from snake venoms and mouths in Thailand.