A notorious veterinary drug that killed millions of vultures in India is now on sale in Europe

In early 2003 I travelled across India to investigate a mysterious scourge that was killing off some of Asia’s most spectacular birds, its vultures. Little did I know that now, more than ten years later, the avian holocaust I witnessed there would be looming over Europe.

Until the early 1990s, India was home to tens of millions of vultures. They were almost everywhere, their presence taken for granted across that country’s wildernesses and into the hearts of its most crowded cities.

The gigantic scavenging birds performed a valuable service, cleaning up the mortal remains of street dogs, sacred cows and even people; members of the ancient Zoroastrian religion had long laid out their dead to be consumed by vultures in specially constructed “towers of silence”.

In the mid-1990s biologists began noting rapid declines in vulture populations across the country. Cities that had hosted thousands of birds were suddenly vulture-free. Animal carcasses that before had been reliably stripped to bone within hours lay rotting for weeks in fields and streets.

Something was killing massive numbers of vultures, but what? Diverse theories abounded, and bitter rivalries developed between scientists jostling for the research dollars flowing towards the crisis.

Some experts told me that vultures were being starved into extinction because westernised Indians were eating more meat, leaving fewer cows for the birds. Others said vulture nest sites on cliffs and in tall trees were being destroyed by the relentless demand for stone and timber, or that unknown pesticides were to blame for their vanishing from the skies.

The most prominent and best-funded Indian scientists were convinced that it was an infectious virus. Nothing else, they told me, could explain the astounding crash in vulture numbers and that many dead vultures were found to be suffering from visceral gout. But despite exhaustive lab analyses of vulture tissues, they still hadn’t identified it.

I then found a site in rural Rajasthan where thousands of vultures fed and roosted together daily — the only large gathering I saw on my whole Indian sojourn — and although the situation presented ideal circumstances for an infectious agent to spread rapidly between birds, I didn’t find a single sick or dead vulture there in days of searching.

When I called the main proponent of the virus theory and his British collaborator to discuss the roost I’d seen, they were oddly uninterested in hearing how apparently healthy the birds were; they’d recently received a large UK grant to study potential routes for the ‘virus’ to travel along to Europe and Africa.

I left India unconvinced that any single factor could explain the die-off, and the birds remained on their trajectory towards extinction.

Shortly after my departure a group of researchers backed by The Peregrine Fund, a US conservation nonprofit, announced a bombshell finding (“bombshell” in terms of emotionally repressed ornithologists, that is). Working in Pakistan, where the machinations of Indian conservation politics had confined them, they’d figured out that a miniscule amount of a pharmaceutical called diclofenac could cause deadly kidney damage in vultures of the genus Gyps, commonly known as griffon vultures.

Three species of griffon vultures, the White-rumped, Slender-billed and Indian Vultures, and a close relative, the Red-headed Vulture, had shown the biggest declines of the nine vulture species found in India.

Diclofenac was developed in the 1970s for human use — it’s a key ingredient of Voltaren gel — but became widely available across India as a cheap veterinary drug in the early 1990s. It was mainly used on cattle to treat inflammation, fever and pain resulting from disease or injury.

The Peregrine Fund established that griffon vultures could ingest lethal amounts of diclofenac in a just a single feeding on the carcass of an animal that had been dosed with the drug shortly before its demise. This extreme sensitivity means that vulture populations can be wiped out even if less than 1% of carcasses available to them are contaminated with the drug.

Conservationists campaigned for years to get diclofenac banned for veterinary use across India (and succeeded) and are now promoting a vulture-friendly albeit somewhat more expensive substitute called meloxicam. This appears to have slowed vulture declines, but the birds are nowhere near safe from extinction yet. Diclofenac that’s been legally packaged for human use is showing up in Indian vet stores, and the drop in vulture numbers over the last 20 years has been so serious that recovery will take decades, even under ideal conditions.

The White-rumped Vulture, formerly known as “probably the most abundant large bird of prey in the world”, with a population of millions, has lost more than 99% of its numbers since the mid-1990s. Less than 15,000 remain. Slender-billed, Long-billed and Red-headed Vultures have declined by well over 90%. All four species are now red-listed as critically endangered, and researchers are figuring out how toxic other anti-inflammatory drugs could be to vultures, and if other scavenging birds share griffon vultures’ sensitivity to diclofenac (‘non-griffon’ vulture species and large eagles are also likely at risk).

The evil genie of cheap diclofenac is hard to force back into its bottle, and conservationists have worked hard to publicise the dangers of the drug and prevent it coming into veterinary use in Africa, home to ecologically important populations of griffon vultures. The continent has generally poor regulation of pharmaceuticals and is rapidly adopting more modern farming techniques, and the potential for an inexpensive drug to spread rapidly there is obvious.

Conservationists haven’t worried much about diclofenac in Europe, where information is readily available and veterinary drug regulation is relatively good.

This turns out to have been a mistake: Vulture researchers were recently stunned to discover that veterinary diclofenac has been authorised for manufacture and use in Italy and Spain and been distributed to other European countries.

“It is shocking that a drug that has already wiped out wildlife on a massive scale in Asia is now put on the market in crucial countries for vulture conservation,” says José Tavares of the Zurich-based Vulture Conservation Foundation.

The drug is manufactured in Italy for some years now and is authorised for use there in cattle, horses and pigs in a medication called Reuflogin. There’s evidence that it’s been exported to the Czech Republic, Latvia, Estonia, Serbia and Turkey.

Last year the manufacture and veterinary use of diclofenac was approved in Spain, the vulture stronghold of Europe. The approval went through without government agents or the drug’s manufacturers speaking to wildlife experts. “Risk assessments were done,” says Tavares “but these do not mention vultures at all, and the competent authorities did not send these risk assessments to any conservation NGO for checking.”

Spain holds by far the majority of all four species of vultures found in Europe: 90% of the continent’s Eurasian Griffon Vultures, 97% of its Cinereous Vultures, 67% of its Bearded Vultures and 85% of its Egyptian Vultures — the latter classified as endangered worldwide.

The birds were almost extirpated from many other European countries during the 20th century as farming practices changed, but they’ve been making a slow return to many of their former haunts thanks to expensive reintroduction projects, many using Spanish birds.

Spain’s vultures feed largely on the carcasses of domestic animals that are placed in traditional carcass dumps called muladares. Even if diclofenac was used sparingly, it’s almost inevitable that significant numbers of vultures will feed on drug-laced carcasses, say experts, because these dumps are poorly regulated and sometimes even illegally operated. Because vultures often forage hundreds of kilometres away from their nest sites, diclofenac’s effects can be felt over massive areas. The drug could easily be sold into Africa, they say.

A coalition of organisations including the Vulture Conservation Foundation, the Royal Society for the Protection of Birds and BirdLife Europe are urgently pushing for an EU-imposed, continent-wide ban on veterinary diclofenac.

“Decades and millions of Euros have been spent protecting Europe’s vultures,” says the coalition, “we should now not let all of them disappear.”

An online petition to ban veterinary diclofenac in Europe has been launched here

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