Management of Snakebite and Research Management of Snakebite ...

Management of Snakebite and Research
86
Development of Russell’s Viper Toxoid
INTRODUCTION
Khin Maung Maung and Win Aung
Biochemistry Research Division
Department of Medical Research (Lower Myanmar)
Abstract
Russell’s viper bite is a serious medical problem in Myanmar. Thus active immunization
of persons at risk is of utmost importance protective measure. Detoxified venom can be
used as effective toxoid for active immunization. Russell’s viper venom (RVV) toxoid was
first prepared with 0.5% formalin. In 1986 formalinized toxoid prepared with Sephadex
G50 (fine) fractionated RVV were tested on monkeys and human volunteers and found to
be safe and immunogenic. In 1980 RVV toxoid was developed by slow and step-wise
formalinization method. The appearance of toxicity in formalinized RVV toxoid stored for
one year at different temperature was found in 1994. In 1996 stability of Sephadex G75
fractionate RVV was tested at room temperature and found to be stable upto six months.
Immunization schedules and age of the toxoid on immunized animals were also studied
in 1996. In 1997, it was found that RVV toxoid with 35% sodium bisulfite were stable
upto one year at 37°C. RVV toxoid lyophilized and stored at room temperature were
found to be less toxic and more immunogenic upto one year. Mice immunized with
toxoid prepared by pooling five major enzymes of RVV could not withstand a lethal dose
of RVV.
Russell’s viper (Daboia russelii siamensis) bite has been a serious medical problem in
Myanmar for many decades. Post-bite administration of antivenom, a product of Myanmar
Pharmaceutical Factory (MPF), is the only effective and widely used treatment. However,
the mortality rate remains considerably high. On many occasions, antivenom treatment is
late and irreversible damage of vital organs has already occurred. Also sometimes, the
development of lesion is so rapid that the antivenom alone cannot neutralize the lethal
effect where large amounts of venom are already introduced into the body. Therefore,
development of a suitable and effective measure i.e. active immunization of people
susceptible to snakebites is of utmost importance as a protective measure. If the victims
are immune to the venom, even to a small degree, the onset of damage is delayed and
they can be treated more successfully (WHO, 1981). Therefore, many attempts have been
made by various scientists to develop of RVV toxoid for nearly three decades in Myanmar.