Russell's viper toxoid: the influence of immunisation schedule and age of the toxoid on antibody response in immunised rabbits and monkeys

The influence of imrnunisation schedule and age of Russell's viper toxoid on antibody response in immunised rabbits and monkeys was studied. Rabbits were immunised subcutaneously with the toxoid at 0,4 and 8 weeks. For subsequent boosting at 6 wk intervals from 24 to 56 wks, fresh toxoid was used in one group (n=3) and the same batch of aged toxoid in another (n=3). lmmunisation of monkeys was carried out up to 40 wks using the latter schedule. Antibody levels peaked at 6-8 wks after the 3rd injection and fell to low level at 24 wks after the first injection. Subsequent boosting at 6 wk intervals from 24 wks onwards resulted in increase in antibody level reaching peak at 12 wk after the 1st booster injection and sustained at its peak throughout the course of immunisation. Antibody response observed in the monkeys was similar to that of the rabbits, however a lower level of antibody was observed. The patterns of antibody response observed following use of both toxoids were comparable. Feasibility and cost effectiveness of boosting at 6 wks intervals in prophylactic active immunisation of farmers at risk with Russell's viper toxoid need to be studied.

Russell's viper bites in Taungdwingyi Civil Hospital:Clinical features and respones to antivenom

One hundred thirty-four Russell's viper (Daboia russell siamensis) bite cases were studies in Taungdwingyi during six months from June to December 1994. Forty percent of the victims were under 20 years of age. Thirty-eight percent showed no evidence of envenoming, 28 percent had local and 34 percent systemic features of envenoming. Ten percent of the cases developed local necrosis. Fifteen percent of the victims received antivenom therapy at the villages. Cases presenting with systemic manifestations had spontaneous systemic bleeding (29 percent); malena (18 percent), hypotension (22 percent), oliguria (42 percent), conjunctival oedema (18 percent) and renal failure (33 percent). Twelve deaths (9 percent) were due to hypotension and renal failure. Spontaneous systemic bleedings were late manifestations and seen from day 2 to 6 after the bite. Thirty-seven percent of the cases with systemic bleeding failed to have normal clot restoration in 6 hours following 40 ml of antivenom administration. Antivenom reactions were observed in 50 percent of the cases. Fifty two percent of juvenile and 19 percent of adult viper bites resulted in blank bites and 16 percent of the former and 31 percent of the latter bites led to systemic envenoming.

Clinical significance of early intravenous antivenom in russell's viper bite casces in Taungdwingyi District:A preliminary study

A retrospective study of 26 Russell's viper (Daboia russelii siamensis) bite cases who received 1-2 ampoules of anti venom at the villages in Taungdwingyi Township was carried out. Sixteen pad-applied cases were included in the study. Pad-treated cases who received early anti venom irrespective of the time after the bite developed no systemic complications (n=0/4) compared to those without pad (n=7/8) or cases who received 4 ampoules of antivenom within 4 hours after the bite at the hospital (n=5/10). Those who received antivenom 4 hours after the bite at the villages irrespective of pad carried the same risk of developing systemic complications compared to those who received 4 ampoules of antivenom at the hospital. Early administration of 1-2 ampoules of anti venom is indicated for treatment of local envenomed cases and 4 ampoules of antivenom should be given to early systemic cases following bites of big snakes. Application of compression immobilisation first-aid technique with an early intravenous anti venom at the villages is to be recommended in Russell's viper bite cases. Antivenom could have been saved in 24 percent of snake bite cases if guidelines for antivenom therapy were properly followed.

Clinical features and response to antivenom of Russell's viper bite cases of Danubyu, Ayeyawady Division

A total of 31 (excluding one cobra bite) Russell's viper bite cases were available for study during 1995-96. The median age of the victim is 24 yr (11-68 yr) and the interval between bite and admission is 4.45 h (2.30-12.oo h). Eighty per cent of the bites occurred in lower limb and 65 per cent were bitten while at work in the field. Length of the snakes varies from 23-110 cm (median 26 cm). Thirteen per cent of the bites are local, 29 per cent no envenoming and 58 per cent systemic of which 67 per cent developed spontaneous systemic bleeding. Nineteen per cent died of renal failure and shock. venom levels of local and systemic are 10-40 ng/ml and 20-199 ng/ml respectively. Clot restoration time in 59 per cent of the cases takes more than 6 h indicating variable efficacy of antivenom in neutralising procoagulant activity of local venom. Albuminuria was detected in 56 per cent. Local blackening (45 per cent) is probably the result of ischaemia and local venom effect.

Clinical features and response to antivenom of Russell's viper bite cases of Myinmu, Sagaing Division

A total of 43 Russell's viper bite cases were studied during 1995-96. The median age of the victim is 27 years (7-71 yr) and the time interval between the bite and admission to the hospital is 1.50 hours (20 min-8.15 h). Sixty per cent of the bites occurred in lower limb and 86 per cent were bitten while at work in the field. Length of the dead snakes brought varied from 23 to 50 cm (median 29 cm). Eighty-six per cent applied tourniquets and 67 per cent carried out immobilisation. Fourteen per cent of the bites developed systemic, 72 per cent local and 14 per cent no features of envenoming. Out of 6 systemic cases, only one presented with a spectrum of spontaneous systemic bleeding. One to 4 ampoules of antivenom was given to all cases irrespective of the state of envenoming. Six antigen negative cases were also given antivenom. Antivenom reactions were present in 21 per cent of the cases. Venom levels of the cases with local and systemic manifestations were 10-45 ng/ml and 50-70 ng/ml respectively. there was no fatality in this study. Vomiting (32 per cent) was observed in non systemic cases as well.

Snake bite in Loikaw with special reference to Malayan pit viper (Calloselasma rhodostoma) bite

A retospective study of 38 snakebite cases admitted to liokaw Divisional Hospital during 1995-96 was carried out. Twenty four were bitten by green pit viper (GPV) (Trimeresurus erythrurus), 13 Russell's viper (Daboia russelli siamensis) and one attributed to Malayan pit viper (Calloselasma rhodostoma). The median age of the victim is 21 year (5-66 yr) and 66 per cent of them are less than 30 years old. It took 11.20 hours (0.30 to 97 h) to get to the hospital. Lower linbs (12/13) were predominantly bitten in Russell's viper bite and both upper and lower limbs were bitten in tr. erythrurus bite. Day bite is 4 times more common than after dark bite. Clinical features of snakebites of both species are similar to those reported ones except spontaneous bleeding: bleeding gums 38.5 per cent (5/13) and epistasis 23 per cent (3/13) are comon in Russell's viper bites. One C. rhodostoma bite confirmed by immunodiagnosis, presented with incoagulable blood developed a deep ulcer which took over 100 days to heal leaving a big scar.

Russell's viper toxoid: Pattern of antibody response following immunisation with toxoid in rabbits

A prospective study of the development and persistence of antibody following immunisation with Russell;s viper toxoid was carried out in rabbits. Two immunisation schedules, each consisting of 3 injections of the toxoid given at 0, 4 and 8 weeks and at 0, 6 and 30 weeks were studied. Booster injections were given at 24 and 60 weeks in the former and at 50 weeks in the latter. The pattern of antibody response of the two immunisation schedules was comparable. Peak antibody response was maintained for 8 weeks after the third injection. No antibody response was observed following boosting at 30, 50 and 60 weeks. Use of aged toxoid and timing of boosting may play an important role in induction of subsequent antibody responses.

Study of venom neutralising efficacy of monospecific cloudy liquid antivenom

Venom neutralizing efficacy of a batch of monospecific cloudy liquid antivenom H 93723 expiry 8-9-97 was assessed retrospectively on seven systemic Russell's viper bite cases. Each received 40 mls (4 ampoules) of antivenom which includes one to four ampoules of cloudy antivenom. Venom antigen and antivenom levels before and after the antivenom were followed up to 72 h by enzyme immunoassay technique. Results indicated that in severe envenomed cases (venom level > 80 ng/ml) (n=4), venom antigen remained detectable up to 8 to 12 h and antivenom was not detected until 4 to 10 h (12-20 h in 2 cases) after the antivenom. Dose related neutralising efficacy of cloudy antivenom was observed. Five out of 7 patients were fatal. Use of cloudy or precipitated antivenom should be discontinued.

Preparation of enteropathogenic Escherichia coli (EPEC) "OK" and "O" antisera for identification of E.coli from diarrhoea cases

Standard strains of enteropathogenic E. coli (EPEC) were used to raise "OK" and "O" antisera in rabbits. The antisera obtained were 01k51, 026k60, 044k74, 055k59, 086k61, 086k62, 0111k58, 0114k90, 0119k69, 0125k70, 0126k71, 0127k63, 0128k67, 0142k+, 0146k89 and 0157k+. A total of 1805 isolates of E. coli isolated from 290 diarrhoea cases and 352 control cases were tested by "OK" antisera by slide agglutination and it was found that 167 isolates showed agglutination. It was then serotyped by using "O" antisera using test tube serial dilution technique and observed that 93 isolates showed agglutination.