Snake bite toll up amid antivenoms’ scarcity

watamu (Kenya) — Snake antivenoms have been around for 125 years, are effective and can be produced cheaply at scale. Yet Africa, with its abundance of deadly snakes, has an alarming shortage of the life-saving medicine.

Experts and campaigners blame a combination of weak production capacity, feeble policy and oversight, high prices and a general lack of concern for the plight of people in poor, remote areas of the world.

The method of antivenom production has changed very little since it was first developed by French immunologist Albert Calmette in the late 19th century. It remains a painstaking, time-consuming process, although researchers are working to develop synthetic alternatives.

First, a technician has to milk a snake’s venom in a dangerous manoeuvre that sees it holding the animal’s head still while it bites a cup covered in plastic film, releasing its poison — a small amount each time — into the container.

Small venom doses are then injected into a large domestic animal, usually a horse, to trigger an immune response and the production of toxin-attacking antibodies.

After several doses over a period of about a year, the horse produces so many antibodies that it becomes immune to the venom, at which point blood can be taken from the animal.

In a lab, antibodies are then separated from the blood, to be given to snakebite victims — who may need several doses.

An antivenom usually works only for a specific species, or small group of species of snake.

A key challenge, especially in poor, remote areas of the world where most snakebites occur, is that most antivenoms need to be refrigerated.

Already patchy, availability of antivenoms in Africa was thrown into disarray when French laboratory SANOFI stopped production in 2014 of its FAV-Afrique drug, which was effective against a number of species, including some of the most dangerous on the continent. The last available doses expired mid-2016.

SANOFI was moved mainly by financial considerations. The prohibitive price of a single dose — more than $100 — rendered sales in Africa unprofitable.

The failure to use antivenom “to save tens of millions of lives... is a shameful failure. Nowhere in the world is this more confronting than in Africa,” says the Global Snakebite Initiative, adding in a report on its website that the “collapse of the snake antivenom market in Africa” was a “medical tragedy”.

The cause is multifold.

In a vicious circle, unaffordability leads to lower demand and falling sales, which result in reduced production, higher costs, and raised prices for consumers.

Even an antivenom produced on the continent and effective against multiple snake species, is nigh impossible to find further north than South Africa, where it is made, a 2018 study by the Liverpool School of Tropical Medicine found. —