Potency assay of the liquid Russell's viper (Daboia russelii siamensis) antivenom stored at different environment

Two methods of storing liquid antivenom (a) keeping it in a sand pot embedded in the ground and another (b) keeping antivenom containing sand pot in a lager sand pot and left in the house with daily and every third day watering of the sand was studied for 7 months covering the winter and hot summer months in Taungoo and Taungdwingyi respectively. Daily watering schedule kept the sand] -2C cooler than the every third day watering and maintained the temperature of the sand at 30-32C with a difference of 8-1 OC lower than the environmental temperature of 40C during the hot summer months. The efficacy of the antivenom stored in the first method with daily watering was found to be comparable to the control and superior to the antivenom stored in the first method with every third day watering and the anti venom stored in the second method with daily watering. It is recommended that liquid antivenom should be stored in a sand pot embedded in the ground with daily watering of the sand in places where no cold storage facility is available. This method of storage is simple, effective and inexpensive and could be carried out by the rural farmers.

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.

Acceptability study of protective boots among farmers of Taungdwingyi Township

Acceptability of fang-proof protective boots was studied in 180 farmers of Taungdwingyi Township during harvesting season, October 1995. The boots were provided free of charge. Preliminary survey showed that 98 per cent of farmers knew snake-bite could be prevented by working with boots on and only 72 per cent wore them whereas 28 per cent non-users could not afford to buy them. At present 88 per cent wear locally available rubber boots, which could not withstand penetration of Russell's viper's fangs. Following the trial, 99 per cent enjoyed wearing the trial boots. These provide full sense of protection against snakebite. These are light, comfortable and the farmers could work with them on for the whole day either intermittently or continuously. Ninety-nine percent preferred to wear the trial boots in future and intended to use them even if these are not provided free of charge. The boots cost 350 kyats per pair. Ninety-nine percent could afford to buy them at a price of 250 kyats per pair, however 1

preferred a lower price of 150 or 200 kyats per pair. 1n order to bring down the incidence of snakebite throughout the country, all-out wearing of the boots is needed and it is suggested that health education, selling and distribution of the boots directly to the users at an affordable (subsidised) price of 250 kyats or less per pair should be aimed at.

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.

A preliminary study of CD4+ T-lymphocyte count in tuberculosis patients

We evaluated the CD4+ T cell count in tuberculosis patients, whether it may be a supportive indicator reflecting the immune status of the patient. A total of 55 patients and 50 controls were included. Patients were within the age range of 19-65 years with a mean of 42.836 + or - 16.24 SD. These included 43 male and 12 female subjects with pulmonary and extrapulmonary tuberculosis. Age and sex matched subjects were included as controls. CD4+ T-lymphocyte count was determined manually with Coulter Manual CD4 Count Kit. A significant reduction in mean CD4 count against control subjects was observed (p=0.004, d.f. 103). A correlation coefficient of 0.546 was observed between CD4 count and percentage of differential lymphocyte count from the peripheral blood. the results indicate that measurement of CD4 count using above method is worthwhile for tuberculosis patients as an adjunct to clinical parameters for the assessment of the immune status of the patient.

Potency assay of antivenom: Batch to batch variation of neutralising efficacy of antivenom

Neutralisation of biological properties of Russell's viper venom (Thayawady) with 4 different batches of monospecific lyophilised antivenom manufactured by Myanmar Pharmaceutical Factory (batch DN 84560B exp. 2/90, DN 86608B exp. 4/92, DH 89652A exp. 9/94 and DD 90668B exp. 6/95) was assessed in rodents using WHO standard tests of neutralising activity. The amount of antivenom required to neutralise different biological properties of venom by different batches of antivenom varied from 2 to 50 times. Such variation of antivenom potency may explain failure of correction of some venom-induced effects seen in antivenom treated Russell's viper bite cases as well as variation in the composition of venom used as an immunogen. No quantitative differences in bands recognised by different antivenoms was observed in immunoblot. It is suggested that characterisation of widely pooled potent venoms to be used for antivenom production and potency assay of antivenom should be carried out routinely.

Potency assay of antivenom: Failure of Indian (serum institute) antivenom to neutralise Russell's viper (Daboia russelli siamensis) venom of Myanmar

Neutralisation of biological properties of Russell's viper (Daboia russelli siamensis) venom of Tharyarwady by a monospecific antivenom of Myanmar (DN 86608B ex. 4/92) and a polyspecific antivenom of Serum Institute of India (Sii) (batch 109 exp. 4/96) was carried out according to WHO standard tests of neutralising activity. Neutralising potency of Myanmar antivenom was superior to the Indian antivenom and the latter required 16-126 times more antivenom than the former in neutralising haemorrhagic, necrotic, lethality, defibrinogenating and capillary permeability increasing activities of the venom. In immunodiffusion and immunoblotting experiments fewer bands were detected in both. It is concluded that the Indian antivenom (Sii) will be less effective in treating Russell's viper bite cases of Myanmar.

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.

Geographical variation of biological properties of Russell's viper venom: Bago Division

Biological properties of Russell's viper venom from four localities (Tharyarwaddy, Lepadan, Waw and Daike-U) of Bago Division were studied according to WHO recommended methods. SDS-PAGE electrophoresis of venoms were also performed. Biological properties of venom of young adults (61-90 cm) and adults (91-120 cm) of each locality were comparable except venom of young adult vipers of Tharyarwaddy possessed weak coagulant activity and that of adult vipers of Waw has potent haemorrhagic and necrotic activities.The adult viper venom of Tharyarwaddy was two times more potent in defibrinogenating and three times in capillary permeability activities than venom ofadult vipers of Lepadan. SDS-PAGE electrophoresis of venoms shows quantitative and qualitative differences in protein bands.

Potency assay of antivenom: neutralisation of biological properties of three Russell's viper venoms by a monospecific antivenom

Potency assay of a monovalent Russell's viper antivenom manufactured by Myanmar Pharmaceutical Factory (MPF) batch DN 866088 exp. 4/92 was assessed with Russell's viper venoms of Tharyarwady, Kungyankone and Daedaye in rodents using WHO standard tests of neutralising activity. There is variation in the amount of antivenom requires to neutralise individual biological property of three venoms and it is noteworthy that 4 times greater amount of antivenom is needed to neutralise haemorrhagic activity of Tharyarwady and defibrinogenating activenom of Kungyankone than the other two venoms. This variable performance of antivenom may be responsible for failure of correction of some venom induced effects seen in Russell's viper bite cases. It is suggested that a wider range of standard assays should be included in characterising the potency of antivenom.

Potency assay of liquid preparation of enzyme refined monospecific Russell's viper antivenoms

Enzyme immunoassay technique (EIA) was used to assess the performance of liquid preparation of enzyme refined monospecific Russell's viper antivenoms manufactured by Myanmar Pharmaceutical Factory, stored at +4 C and room temperature at two township hospitals. The antivenoms stored at +4 C with a shelf life of less than 1/2 year, time expired precipitated antivenoms and batches of antivenom stored at room temperature with a shelf life of one year have lost venom neutralising activity and also venom antigen was detected in the urine. The poor performance of liquid antivenom probably results from batch to batch variation and incorrect storage of antivenom.