Factors contributing to fatal snake bite in the rural tropics: analysis of 46 cases in Thailand.

Records of 46 cases of fatal bites by identified snakes from 15 provincial hospitals throughout Thailand contained sufficient information for detailed analysis. Bungarus candidus and Calloselasma rhodostoma were each responsible for 13 deaths, Naja kaouthia for 12, Vipera russelli for 7 and B. fasciatus for one. Major causes of death among elapid victims were respiratory failure (26) and complications of prolonged mechanical ventilation (10), and among viper victims shock (12), intracranial haemorrhage (9), complications of local wound necrosis (7) including tetanus (2), and renal failure (2). Factors contributing to fatal outcome included inadequate dose of antivenom (15 cases), misidentification of the snake leading to use of the wrong antivenom (12), problems associated with mechanical ventilation (10), and delayed arrival in hospital after traditional (herbal) treatment (10). Similar problems have been identified in other tropical countries. Education of medical staff and the patient population at highest risk could reduce snake bite mortality

Antimalarial effects of rifampin in Plasmodium vivax malaria.

The antimalarial effects of rifampin in 60 adults with Plasmodium vivax malaria were assessed. There were three treatment groups: rifampin (20 and 15 mg/kg of body weight per day for 1 and 4 days, respectively; n = 5); rifampin followed by primaquine (15 mg of base per day for 14 days; n = 25), and chloroquine (25 mg of base per kg over 3 days) followed by primaquine (n = 30). All patients were hospitalized till clearance of fever and parasites, and 45 patients stayed in the hospital for 1 month. Despite initial clearance of fever in all patients and a > or = 6-fold reduction in parasitemia per 48-h life cycle, rifampin alone was not effective: all five patients had subsequent R2-like parasitological responses. All patients treated with rifampin-primaquine cleared both fever and parasitemia, but the therapeutic responses were slower than those following treatment with chloroquine-primaquine. Final fever clearance times were significantly longer (mean [standard deviation] = 43 [35] versus 27 [19] h; P = 0.046), and the parasite clearance times (to 50 and 90% of admission parasite counts and to a level undetectable in a peripheral blood smear) were also significantly greater (P = 0.053 to < 0.001). However, reappearance of infection occurred in only one patient treated with rifampin-primaquine. The results of this study suggest that rifampin at the usual therapeutic doses has partial activity against blood stages of P. vivax in humans but that used alone it is insufficient for cure. Rifampin might therefore be of value in combination antimalarial therapy

Antimalarial effects of rifampin in Plasmodium vivax malaria.

The antimalarial effects of rifampin in 60 adults with Plasmodium vivax malaria were assessed. There were three treatment groups: rifampin (20 and 15 mg/kg of body weight per day for 1 and 4 days, respectively; n = 5); rifampin followed by primaquine (15 mg of base per day for 14 days; n = 25), and chloroquine (25 mg of base per kg over 3 days) followed by primaquine (n = 30). All patients were hospitalized till clearance of fever and parasites, and 45 patients stayed in the hospital for 1 month. Despite initial clearance of fever in all patients and a &gt; or = 6-fold reduction in parasitemia per 48-h life cycle, rifampin alone was not effective: all five patients had subsequent R2-like parasitological responses. All patients treated with rifampin-primaquine cleared both fever and parasitemia, but the therapeutic responses were slower than those following treatment with chloroquine-primaquine. Final fever clearance times were significantly longer (mean [standard deviation] = 43 [35] versus 27 [19] h; P = 0.046), and the parasite clearance times (to 50 and 90% of admission parasite counts and to a level undetectable in a peripheral blood smear) were also significantly greater (P = 0.053 to &lt; 0.001). However, reappearance of infection occurred in only one patient treated with rifampin-primaquine. The results of this study suggest that rifampin at the usual therapeutic doses has partial activity against blood stages of P. vivax in humans but that used alone it is insufficient for cure. Rifampin might therefore be of value in combination antimalarial therapy

ELISA confirmation of acute and past envenoming by the monocellate Thai cobra (Naja kaouthia).

The monocellate Thai cobra (Naja kaouthia) is a major cause of snake bite mortality and morbidity throughout Thailand, but neither the local nor the systemic effects of its venom are diagnostic. Species diagnosis is important because only monospecific antivenoms are available for treatment in Thailand. We tested the ability of the ELISA technique to detect venom antigen in the sera of 58 acute snake bite cases including 4 fatalities, and venom antibody in 51 patients bitten between 1 month and 19 years previously. N. kaouthia venom antigen was found in 8 of 33 patients with only local envenoming and in 14 of 20 with local plus systemic (neurotoxic) envenoming, but the mean venom concentration was 33 times greater in the latter group. The serum of 1 fatal case contained banded krait (Bungarus fasciatus) but no cobra venom antigen. N. kaouthia venom antibody was present in sera of patients bitten between 1 month and 7 years previously. Antibody was found in 6 of 8 patients who had had local envenoming alone but in only 19 of 41 who had had systemic envenoming treated by antivenom. The titer of antibody declined with an approximate half time of 2-3 years. One patient had a significant titer of B. fasciatus venom antibody. This study confirms the value of ELISA-immunodiagnosis and the predominance of N. kaouthia as a cause of neurotoxic envenoming in the Bang Phli area. However, the attribution of 1 fatal case to B. fasciatus bite suggests that patients with neurotoxic signs should be given B. fasciatus antivenom if they fail to respond to cobra antivenom

Detection of venom by enzyme linked immunosorbent assay (ELISA) in patients bitten by snakes in Thailand.

The ability of an enzyme linked immunosorbent assay (ELISA) to detect venom was evaluated in 251 patients bitten by four of the commonest poisonous snakes in Thailand. Serum was tested only from patients who brought the snakes that had bitten them. About one third of all bitten patients had detectable venom antigenaemia, though a smaller proportion were symptomatic. Serum venom concentrations on admission correlated with the severity of clinical manifestations. The test was sensitive and specific even for specimens that had been collected and stored under suboptimal conditions. The technique is suitable for forensic use in cases of suspected snakebite. The combination of snake identification and venom antigen detection should be a more reliable means of studying the epidemiology of snakebite than the measurement of venom antibodies in a population

Detection of venom by enzyme linked immunosorbent assay (ELISA) in patients bitten by snakes in Thailand.

The ability of an enzyme linked immunosorbent assay (ELISA) to detect venom was evaluated in 251 patients bitten by four of the commonest poisonous snakes in Thailand. Serum was tested only from patients who brought the snakes that had bitten them. About one third of all bitten patients had detectable venom antigenaemia, though a smaller proportion were symptomatic. Serum venom concentrations on admission correlated with the severity of clinical manifestations. The test was sensitive and specific even for specimens that had been collected and stored under suboptimal conditions. The technique is suitable for forensic use in cases of suspected snakebite. The combination of snake identification and venom antigen detection should be a more reliable means of studying the epidemiology of snakebite than the measurement of venom antibodies in a population