All about antivenom
Although Buddhist monks have been drinking snake venom to build up immunity to certain snake bites for hundreds of years, antivenom as we know it today was first developed in the early 1900s and is produced by various companies around the world. In South Africa, antivenom is made by the South African Vaccine Producers, which falls under the National Health Laboratory Service.
Making antivenom is a time-consuming and expensive process during which animals like horses, sheep and camels are hyperimmunised against snake venom. In South Africa we use horses. How, you ask? A very small amount of snake venom is injected into the horse to activate its immune system. This is followed periodically by gradually increasing quantities until the horse becomes immune to the venom. The process usually takes about nine months. Blood is then drawn from the horse and the antibodies are collected and purified. This is what is used to make the antivenom.
Two antivenoms are made for southern African snakes – a monovalent boomslang antivenom that is seldom used as these snakes seldom bite, and a polyvalent antivenom that covers ten other dangerous snake species including cobra, mamba, rinkhals, puff adder and Gaboon adder.
Antivenom is highly effective in serious snakebite cases, provided it’s injected sooner rather than later and at the right quantity. This should only be done by a medical doctor in a hospital environment, because antivenom can have side effects. Some patients develop an allergic reaction and have been known to go into anaphylactic shock.
Knowing what snake was responsible for the bite is not vital – doctors simply look at symptoms and treat accordingly.
Antivenom is not cheap to make and is only needed once in a blue moon. For that reason, the average treatment where antivenom is administered and the patient spends a few days in ICU can cost R100 000 or more. Only about one in ten snakebite victims who are hospitalised receive antivenom, since the symptoms of being bitten usually do not justify such radical treatment.
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