UAE/ UK: Scientists work to produce potentially life-saving snake anti-venom from anti-bodies produced in camels' blood

Record ID: 455298

  • Title: UAE/ UK: Scientists work to produce potentially life-saving snake anti-venom from anti-bodies produced in camels' blood
  • Date: 5th February 2007
  • Summary: (AD1) MOMBASA, KENYA (FILE) (REUTERS -- ACCESS ALL) EXTERIOR OF SNAKE SANCTUARY VARIOUS OF VENOMOUS SNAKES
  • Embargoed: 20th February 2007 12:00
  • Keywords:
  • Topics: Nature / Environment,Health
  • Reuters ID: LVA6SLQJAQNO0PSF7ZTMD4PVAY19
  • Story Text: Scientists in the United Kingdom, the United Arab Emirates and Costa Rica are collaborating to produce an antidote to snake venom that could save thousands of lives across Africa every year, by injecting camels with the poison and extracting the resulting antibodies from their blood.

    Scientists in the United Arab Emirates, the United Kingdom and Costa Rica are collaborating to produce a snake anti-venom extracted from the blood of camels.
    The scientists are hopeful the anti-venom will prove more effective than conventional anti-venoms used to treat humans bitten by poisonous snakes.
    If clinical trials live up to their hopes, they say the new anti-venom could save thousands of lives, especially in West Africa where several species of deadly snakes live and where the death rate from snake bites is one of the highest in the world.
    Scientists at the Central Veterinary Research Laboratory (CVRL) in Dubai immunise the camels with progressively larger doses of snake venom, and extract the resulting anti-bodies from the camels' blood.
    "We produce here and our camels which you see behind us an anti-venom against the most deadliest snakes from Africa," explained Dr. Urlich Wernery, scientific director at the CVRL.
    "We inject a small amount of venom under the skin of these camels and camels produce a special anti-body," he added.
    The collaboration is based in the United Kingdom, at the Alistair Reid Venom Research Unit at the Liverpool School of Tropical Medicine. Scientists and specialists extract the venom that is used to immunise the camels against the poison of three types of highly venomous snakes kept at the research unit.
    Head of the unit Dr. Robert Harrison said some 120,000 people die each year from snake bites. A large percentage of these deaths occur in West Africa.
    Harrison said some types of snake venoms can attack the human nervous system and cause paralysis, while other types have a local tissue-destroying effect.
    Anti-venoms produced from horse and sheep anti-bodies, administered intravenously, are currently the only effective treatment against envenoming.
    But these conventional anti-venoms leave much to be desired, for three main reasons. Their molecular composition means they are unable to enter human blood and tissue and are therefore ineffective against local, tissue-destructive effects of envenoming. They can also cause severe allergic reactions in some patients, and they need refrigeration, which means that they cannot be kept in some of the rural tropical areas which need them most.
    Harrison explained that his team is hopeful that sera produced from camel anti-bodies can address each of these problems.
    "Camels are unique in the animal kingdom, with the exception of the nurse shark, in that a lot of their anti-body is, instead of being a large molecule like the sheep or the horse anti-body, is very much smaller. And it's that smallness that indicates to us that it might be useful when we give it intravenously, through the blood stream of an envenomed victim, that it can pass through the blood tissue barrier and get into the tissue to neutralise the pathology that's occurring in the tissues," Harrison said.
    Harrison added that a study from the University of Costa Rica has suggested that a camel anti-venom would be, for reasons as yet unknown to scientists, far less likely than sheep or horse anti-venoms to cause adverse allergic reactions in humans.
    Finally, other studies have suggested that a camel anti-venom could be stored at room temperature.
    When the Liverpool, Costa Rica and United Arab Emirates collaboration heard of the uniqueness of camel anti-bodies, the team conducted a pilot study with camels in Yemen and llamas -- the close relatives of camels -- in the Netherlands. The preliminary study demonstrated that these animals react to venom immunisation with the same degree of efficiency as that of horses or sheep immunised with venom.
    As a result of that preliminary trial, the team of scientists decided to make an anti-venom for West Africa.
    For that they are collecting the venoms of the saw-scaled viper, the spitting cobra and the puff adder, all native to that region, and are using these venoms to immunise the camels in Dubai.
    At regular intervals, highly specialised staff members remove the venom from -- or "milk" -- the dozens of snakes kept at the venom research unit. They milk the small but aggressive saw-scaled viper, which grows no longer than 50 centimetres (19.7 inches) and causes more deaths than any other snake in West Africa, once every month.
    Two men help each other in taking the snake out of its box with a special hooked stick, grabbing hold of the snake just below its head and pressing its fangs into a container covered with a thin translucent film. The snake's reflexes cause it to release its venom into the container.
    The venom is then freeze-dried and stored. Batches are sent to Dubai to immunise the camels.
    Harrison explained that when the anti-body count becomes sufficiently high in the immunised camels' blood, the team will send large volumes of those sera to the University of Costa Rica, where a cost-effective anti-venom will be produced from the camel serum.
    The scientists will look at the pre-clinical efficacy of the anti-venom in Liverpool, and if they are deemed as effective as the conventional treatment, they will test them in clinical trials in West Africa.
    This is all for the future, stresses Harrison. But, if the clinical trails do indeed live up to hopes raised by the unique attributes of camel anti-bodies, the resulting anti-venom could well prove a breakthrough in treating potentially fatal snake bites.
    "We are particularly gratified here at the School of Tropical medicine to be given the opportunity to develop a product that may significantly improve the lives of people who are bitten by snake bite in rural tropical African countries. This is completely in line with a recent World Health Organisation initiative to not only improve the manufacture of anti-venoms but also improve the delivery of anti-venoms to people, communities that most need it," Harrison said.
    With luck, the scientists will also be able to come up with anti-venom for other deadly African snakes, like the green and black mamba, seen here at a snake park in Mombasa, Kenya. These snakes are responsible for hundreds of deaths in Africa every year.
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