Antibody response of patients after postexposure rabies vaccination with small intradermal doses of purified chick embryo cell vaccine or purified Vero cell rabies vaccine.

Although the introduction of tissue culture vaccines for rabies has dramatically improved the immunogenicity and safety of rabies vaccines, they are often prohibitively expensive for developing countries. To examine whether smaller doses of these vaccines could be used, we tested the safety and immunogenicity of purified chick embryo cell vaccine (PCECV) on 211 patients in Thailand with World Health Organization (WHO) category II and III exposures to rabies. The patients presented at two Thai hospitals and were randomized into three groups. Patients in Group 1 received 0.1 ml PCECV intradermally at two sites on days 0, 3, 7, and at one site on days 30 and 90. Group 2 was treated similarly, except that purified Vero cell rabies vaccine (PVRV) was used instead of PCECV. Group 3 received 1.0 ml PCECV intramuscularly on days 0, 3, 7, 14, 30 and 90. After 0, 3, 7, 14, 30 and 90 days serum was collected from the subjects and the geometric mean titres (GMTs) of rabies virus neutralizing antibody determined. After 14 days the GMT of 59 patients vaccinated intradermally with PCECV was equivalent to that of patients who received PVRV. Adverse reactions were more frequent in patients who received vaccines intradermally, indicating the reactions were associated with the route of injection, rather than the vaccine per se. We conclude that PCECV is a safe and highly immunogenic vaccine for postexposure rabies vaccination when administered intradermally in 0.1-ml doses using the two-site method ("2,2,2,0,1,1") recommended by WHO.

A study of epidemiology, risk factors and preventive measures against snake bites.

The epidemiology and exposing causes of snake bites were studied in 274 patients between 1 January 1982 and 30 December 1990. They comprised 142 males (51.82%) and 132 females (48.18%). Their ages ranged from 1 month to 86 years old. The age group most frequently bitten found in this study was between 15 to 29 years old amounting to 106 cases (38.69%). Of those 274 cases, 212 (77.37%) were the victims of poisonous snakes, namely, the green pit viper (Trimeresurus spp.) 156 cases (73.58%), the cobra (Naja naja) 53 cases (25.00%), Russell's viper (Vipera russellii siamensis) 3 cases (1.42%), while 13 cases (4.74%) were bitten by non-poisonous snakes, and in the remaining 49 cases (17.88%), the biting snakes were not clearly seen. It was found that 56 cases (20.44%) were bitten in the house, 50 cases (18.25%) were bitten within the precincts of the residence. However the highest number, 168 cases (61.31%) were bitten outside. It was also interesting to learn that 221 cases (80.66%) out of 274 were bitten in Bangkok, 91 cases (33.21%) were bitten from 6.00 p.m. to 9.00 p.m., 129 cases (47.08%) were bitten between June and September, 98 cases (35.77%) were bitten on a foot and 77 cases (28.10%) were bitten on a finger. The high risk factor of being bitten by a snake was walking along a farm or a ranch with masses of grass or undergrowth during the night without self-prevention and good caution. Therefore, health education on preventive measures were elucidated.

Dark green pit viper (Trimeresurus popeorum) bite: clinical and serial coagulation profiles in 51 cases.

Trimeresurus popeorum, a dark green pit viper, is commonly found in Southeast Asia. This study describes the clinical picture and blood studies of 51 patients bitten by this snake. Affected limbs were swollen; and hemorrhagic blebs in fingers and toes were found in 12 patients. Lymphangitis was observed in 4 instances. Six individuals exhibited hypofibrinogenemia of 0-84 mg/dl, and 2 cases developed thrombocytopenia and bleeding. The presence of venom in the blood of these patients was demonstrated. Positive fibrin degradation products of 40-320 micrograms/ml were observed in 6 cases with hypofibrinogenemia, and in 8 other cases. Nineteen patients had short euglobulin lysis times of 51.8 +/- 24.7 min. Hyperfibrinogenemia of 626.7 +/- 288.9 mg/dl was found in 18 cases. Apart from bleeding, there were no systemic symptoms. Hypofibrinogenemia became normal in 3-12 days. The clinical course in all patients was uneventful, and none received antivenin.

Hygienic status of food handlers.

The study demonstrated bacterial species on hands and nails of food-handlers before and after hand-washing. Those were Staphylococcus spp., Streptococcus spp., Micrococcus spp., Bacillus spp., Diphtheroid, Aeromonas hydrophila, Klebsiella pneumoniae, Acinetobacter, Enterobacter cloacae, Escherichia coli, Pseudomonas spp., Proteus mirabilis, Serratia spp., Citrobacter freundii. Before hand washing, each food-handler harboured one to eight bacterial species. After hand-washing (eight with water from plastic boxes, 97 from pipe water, 57 out of 97 (58.8%) used soap or detergent with water), disappearance of one to four bacterial strains from hands and nails were found in 47.6 per cent of food-handlers. Cultures of water used for washing from eight plastic boxes yielded Staph. spp., Strep. spp., Aeromonas hydrophila, Kleb.pneumoniae, Acinetobacter anitratus, Enterobacter cloacae. From pipe water, Diphtheroid in 4, 4.1 per cent Micrococcus in 1, 1.03 per cent were shown. Comparing bacterial species found in food-handlers with long nails and short nails, 4-8 more species were revealed in the former than the latter for 35.7 per cent. After hand-washing, there was recontamination of bacterial species in 17 food-handlers. This was probably due to dirty napkins or dresses during hand-drying or from water in plastic boxes.

Severe cases of green pit viper snake venom poisoning.

Two severe cases of green pit viper bites were reported. The clinical manifestations were severe bleeding and diarrhea. The first patient had acute renal failure complicated from severe diarrhea and hypovolemia. Hematological findings showed hypofibrinogenemia and thrombocytopenia. Renal biopsy performed in the first case showed a picture compatible with that of the recovery phase of acute tubular necrosis. Green pit viper antivenine serum together with symptomatic and supportive treatment was given. Both patients recovered uneventfully.

Systemic and intestinal immunities after different typhoid vaccinations.

The comparative studies of systemic and intestinal immunities to S. typhi were performed in 29 healthy volunteers during 2 years after receiving oral vaccination with attenuated S. typhi Ty21a in gelatin capsule, parenteral vaccination with acetone inactivated or heat inactivated-phenol preserved S. typhi Ty2. The methods used were immunobead ELISA for total secretory IgA and indirect ELISA for specific secretory IgA in the intestinal lavage fluid. The specific systemic IgG, IgM and anti-O, anti-H agglutinins were measured by indirect ELISA and Widal test respectively. The leukocyte migration inhibition test was used for the measurement of systemic cell mediated immunity. The results indicate that the oral S. typhi Ty21a stimulated intestinal immunity better than both parenteral vaccines but evoked less systemic antibody response. The stimulation of systemic cell-mediated immunity by the live attenuated and acetone inactivated vaccine was comparable while stimulation by heat inactivated-phenol preserved vaccine was less pronounced. The same studies were performed in 26 healthy volunteers during 6 months following different doses of oral vaccination with S. typhi Ty21a in enteric-coated capsule. The results suggest that the stimulation of intestinal and systemic immunities by this vaccine is dosage dependent. Three doses of vaccine provide better stimulation than two doses and one dose, respectively.

Prolonged defibrination syndrome after green pit viper bite with persisting venom activity in patient's blood.

Venom activity in citrated plasma from a patient with a green pit viper bite was demonstrated by measuring its ability to decrease fibrinogen levels in normal plasma for six days after the bite. By in-vitro study, the minimal amount of crude venom to induce hypofibrinogenemia was 0.5 microgram/ml of normal plasma. The findings explained the continuing defibrination with bleeding and especially the failure of fresh-frozen plasma transfusion to correct hypofibrinogenemia in this patient. The most beneficial therapy should therefore be the neutralization of venom by antivenin, for as long as abnormal coagulation profiles are present, to discontinue the defibrinating process. The preparation of potent antivenin must be encouraged.

Clinical manifestations of cobra bite in the Thai farmer.

Twenty cases of cobra bite in farmers from the central region of Thailand are reported. Ptosis is the earliest sign of cobra bite and is an important diagnostic indication of systemic poisoning. Restlessness, irregular breathing and mental confusion are warning signs of respiratory paralysis. Antivenom for cobra bite was administered intravenously together with symptomatic and supportive treatment; 19 patients survived and 1 died from cerebral anoxia.