Snakebit: Surviving the Black Mamba

From Snake … to Horse?

It starts with snake farmers who are employed by pharmaceutical companies to "milk" the venom from a snake — getting the snake to phantom bite and extracting the venom, referred to as "harvesting" the poison. Then a small dose is injected into a horse.

Horses work well because they have a lot of blood volume, says Dr. Njuguna.

"Small amounts of the venom can be injected without hurting the horse," she says. "It's how many vaccines and serums are made."

But all 10 venoms cannot be injected at once. At least three months between every two injections is needed.

Once the horse has all the injections, its blood containing the 10 anti-bodies is extracted. According to Dr. Njuguna, the blood must then be purified and pasteurized before it can be given to human beings. That way, she says, "you only get the 'FAB,' or fragment antigen binding," meaning that the serum will be pure and won't be rejected by the human body.

After that, the serum is actually tested on humans at a snake bite center. Most are located in West Africa, which has the most serious bite problem. It can take more than a year to produce just one dosage.

Dangerous Reactions

Even with the long and careful serum process, people still have serious allergic reactions to the anti-venom, says Njuguna. Some experience have immediate anaphylaxis, in which their bodies reject the anti-venom outright and they go into shock. That reaction is rare, but as precaution clinics that treat snake bites also have adrenaline on hand to counteract any allergic reaction.

The most common allergic reaction is referred to as "serum sickness," in which a person feels ill several days after taking the serum.

One of the ways health care workers are taught to reduce reactions is by diluting the serum with saline before administering it. But the black mamba is so deadly that it is recommended that the anti-venom be injected directly into the bloodstream — and fast.

The anti-venom "neutralizes the venom immediately," says Njuguna. "With Mamba poisoning you're racing against time."

The horrible effects of the venom make any allergic reaction worth the risk. In fact, with black mamba bites even children are given the full anti-venom dose, says Njuguna. It's even more important in children because the poison spreads much quicker through the body.

High Price for Life-Saving Serum

Putting the anti-venom serum in rural hospitals and clinics is costly. After being bitten, a person needs two doses of the serum, and each dose costs around $200 — an enormous amount of money for countries where the majority of the rural population survives on little more than a dollar a day.

Also, the venom has a shelf life of no more than three years, meaning that if it's been a "good year" for snake bites, the serum won't be used and could get tossed out.

By 2000, pharmaceutical companies had almost stopped manufacturing snake anti-venom serums because of a lack of orders. But once the WHO decided to address snake bites as a public health issue in Africa, governments followed. And the development of the 10-in-one serum cut costs dramatically.

Kenya, in particular, has decided to tackle the problem head-on. Besides the ongoing educational campaign, the Kenyan government continues to underwrite the costs of stocking and administering the serum throughout the country.

"The government ordered 27,000 doses this year," says Dr. Njuguna.

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