28 September 2017.
For immediate release
A study published online this month in the scientific journal Chemosphere, has shown the lethal effects to vultures of a popular painkilling drug used in the cattle farming industry. The toxic drug is known as carprofen and is from the same family of drugs as diclofenac. The frequent and widespread use of diclofenac to treat cattle and buffalo in south Asia is what was responsible for the catastrophic population declines in vultures in that region. Birds that consumed the carcasses of livestock treated with diclofenac experienced sever renal failure and death within hours to days. As a result, five species of South Asian vulture are now endangered or critically endangered.
Against this background, conservationists in South Africa are extremely concerned about the impact of similar veterinary drugs on the vultures which are indigenous to this region. To better understand the impact of non-steroidal anti-inflammatory drugs (NSAIDs) on southern African vultures, a team of researchers from the University of Pretoria, the United Kingdom and associated conservation partners have been conducting a range of toxicity trials. So far, only one common drug, meloxicam, has been shown not to kill vultures at the maximum level of exposure in a carcass. Tens of drugs belong to this family and the toxicity of most remains unknown.
Professor Vinny Naidoo, a co-author of the study and Director of the Biomedical Research Centre, University of Pretoria, South Africa, says: “We wanted to safety test carprofen because we had some evidence that this drug might be non-toxic to vultures. This would provide vets and farmers another vulture-safe alternative to diclofenac.”
When cattle are treated with carprofen, the drug collects in the kidneys and in the tissue around the site of the injection. In a controlled experiment, vultures were given kidney tissue rich in carprofen or pure carprofen at the maximum levels measured in kidney tissue. These vultures showed no toxicity. However, the researchers found that carprofen concentrations were much higher at the injection site than in the kidneys or liver of the cattle used in the experiment. One of two vultures exposed to the average concentration found at the injection site died. Post mortem examination of this vulture found severe kidney and liver damage evident of NSAID poisoning.
“Our NSAID safety testing provides the critical evidence needed to bring about bans and save tens of thousands of vultures,” says Toby Galligan, a co-author of the study and Senior Conservation Scientist at the RSPB Centre for Conservation Science, UK. “We carefully designed our experiment to minimise the number of vultures that may die for that cause.”
The researchers concluded that carcasses of cattle treated with carprofen were generally harmless to vultures; however, cattle vary in their absorption of the drug, resulting in some having very high concentrations at the injection site. In addition, vultures vary in their elimination of the drug, resulting in some suffering renal failure and death. In summary, some vultures will die from eating some carcasses of cattle treated with carprofen. While carprofen is not as toxic to vultures as diclofenac, it is also not as vulture-safe as meloxicam.
“We are talking about critically endangered species of vulture – we cannot afford to lose any to carprofen or any other known unsafe NSAID,” says Kerri Wolter, a co-author of the study and founder of South African vulture conservation organisation, VulPro. “Carprofen should not be used to treat livestock in regions where the carcasses of these livestock are provided to vultures.”
Yet, carprofen is commonly used to treat livestock in South Africa and livestock carcasses are provided to them at numerous feeding stations. In south Asia, carprofen is recommended for use in dogs only, but there, unqualified para-vets often ignore recommendations as evident by their misuse of diclofenac intended for humans.
It is imperative that farmers and vets be aware of the dangers of this drug in order to prevent southern African vultures from facing the same fate as their south Asian cousins.
The peer-reviewed paper on this study can be accessed online through ScienceDirect at https://doi.org/10.1016/j.chemosphere.2017.08.167.
For further information, contact Kerri Wolter at email@example.com or 082 808 5113.
More information on VulPro can be found at www.vulpro.com
High resolution photographs of vultures, feeding sites and vulture clinical trials are available on request.
28 September 2017.