The green, left, and black mambas are among South Africa’s most venomous snakes. Picture: African Snakebite Institute
ANTIVENOM stock shortages are “dire” as South Africa approaches summer and snakes become more active.
It’s estimated that about 4 000 South Africans are bitten by snakes every year, mostly in the evening, and everyone is at risk no matter in which part of the country they find themselves.
African Snakebite Institute CEO Johan Marais said the current antivenom stock situation was dire, even though fewer than 15% of snakebite victims need and receive it.
“Most major hospitals in high risk areas carry some antivenom, but often have far too little in stock. For a serious snakebite the initial dosage is around 6-12 vials of polyvalent antivenom and additional vials may be required.”
Marais said in South Africa antivenom was only manufactured by the South African Vaccine Producers (SAVP), an entity which falls under the National Health Laboratory Service.
He said there had been stockouts from time to time in the past because of various issues but the situation had worsened.
“It appears that SAVP has no stock and nothing is being produced. Unfortunately, it is not possible to get any answers from SAVP, but in a recent email, they confirmed that they could not supply antivenom at present,” he said.
“In the last few years, sort of since Covid, their (SAVP) wheels have come off completely and they ran into major production problems.”
Marais said many doctors battled to get antivenom and a lot of the antivenom available was used on dogs.
“Dogs are hunters, they see a snake and they try to get it so they get bitten. People rush to a vet and the vet cannot buy antivenom, it’s not available and he’s just told that, sorry, we don’t have stock,” said Marais.
Antivenom is the only effective treatment for a serious bite of a highly venomous snake and is also very expensive.
“For an average puff adder bite in South Africa, the anti-venom will cost about R15 000. For an American rattlesnake bite you can easily pay half a million rand or more. That’s just for the antivenom, not the treatment, not the doctors, not the ICU, none of that.”
Marais said the laborious process used to manufacture antivenom had been the same since 1903.
“We hyperimmunise horses with snake venom. The hyperimmunisation takes about nine months. We draw blood from the horse, we squeeze the serum out and that serum is then purified and that is what neutralises the snake venom. So anti-venom is horse serum.”
Apart from the actual manufacturing process, you need many horses which must also be fed, have a place to stay and vet bills must be paid, he said.
“It’s a very laborious process. You can only bleed a horse every two months, you can take nine litres at a time. So it’s a very expensive process. It’s not a production line like making headache tablets,” he said.
While some companies used sheep to manufacture antivenom that was more expensive, he said
Marais said the most popular antivenom used in South Africa is a polyvalent antivenom which is made from the venom of ten different snake species and covers the potentially lethal snakes like the mambas, cobras, gaboon adder, puff adders and rinkhals. The one exception is the boomslang which has its own antivenom, a monovalent antivenom, but because the boomslang just about never bites people, it’s rarely used. Marais said estimated that there were perhaps only half a dozen bites per year.
Panaf Premium is an antivenom imported from India but the downside is that patients need double the amount than the polyvalent made by SAVP which means it’s also more costly, Marais said.
While the availability of antivenom is a major issue, getting victims to a hospital in time is part of the problem. According to Marais it can take a snakebite victim in rural Zululand an average of six hours from the time they are bitten to their arrival at a hospital.
The World Health Organization said snakebites were a neglected public health issue in many tropical and subtropical countries and most of these occured in Africa, Asia and Latin America. It said in Africa there were an estimated 435 000 to 580 000 snake bites annually that needed treatment.
“Envenoming affects women, children and farmers in poor rural communities in low-and middle-income countries. The highest burden occurs in countries where health systems are weakest and medical resources sparse,” according to the WHO.
It says bites by venomous snakes can cause severe paralysis that may prevent breathing, cause bleeding disorders that can lead to fatal haemorrhage, cause irreversible kidney failure and severe local tissue destruction that can cause permanent disability and limb amputation.
Dr Kevin McEwen, a trauma doctor in the emergency department at Netcare St Augustine’s Hospital in Durban, said that while snakebites were more common in summer, KZN’s warm climate meant they could happen at any time of the year.
“Snakes are far more likely to come into contact with people in the hotter months when they’re livelier and breeding. That’s when we see an increase in the number of people seeking often-lifesaving treatment for snakebites.”
McEwen said some of the most venomous snakes in KwaZulu-Natal were the black and green mambas which are neurotoxic (nerve toxic) venomous snakes.
“The cobras, including the spitting cobra, which has a mixture of nerve and cell venom, are also very dangerous. While the bite of a puff adder is serious in terms of cell damage, we don’t see them around urban areas so much. They’re more likely to be found in the bush in places like northern KwaZulu-Natal.”
However, the most common bite they saw at the hospital was from the stiletto snake or burrowing adder.
“People make the mistake of thinking the stiletto snake is harmless and pick it up with their hands. They don’t realise that the stiletto snake has sharp fangs on either side of its mouth and it can move independently of the other. When people try to pick them up behind the neck, it can easily spike its fangs into your finger. It’s a brilliant defence technique, so it’s the most common snake bite we see.”
He has cautioned snakebite victims not to take a wait-and-see approach because neurotoxic venom could start working as rapidly as within half an hour.
By the time of going to print the National Health Laboratory Service had not yet responded to requests for information.
The African Snakebite Institute can be contacted on 082 494 2039, e-mail johan@asiorg.co.za or the website www.africansnakebiteinstitute.com where you can find extensive information about dealing with snakebites and contact details of local snake removers.