The overuse of drugs in large-scale agriculture poses a variety of risks to human health. But one that played out in India and the surrounding countries was remarkably indirect: an overabundance of rotting cow carcasses. Thanks to repeated government interventions, the root of that problem—plunging populations of vultures—may finally be on the mend.
The problem started with an anti-inflammatory drug, diclofenac, that was being mass-produced after the patents on it had expired. It found widespread use in veterinary settings in India, Bangladesh, Nepal, and Pakistan. From there, it made its way to the vultures. These birds normally scavenge a large number of cow carcasses that would otherwise end up rotting in the open. Unfortunately, as the drug ended up building up in the vultures, it caused fatal kidney toxicity. Populations of some species plunged to one percent of their historic levels—and the bodies of dead cattle began festering in the countryside.
A perspective in today's issue of Science tracks the efforts involved in saving the vultures. Several of the countries first banned diclofenac in 2006, but that turned out to be only a partial solution. Doses of the drug intended for humans were repurposed for the agricultural market, so further interventions were needed before the contamination problem ended up dropping significantly. Since then, the four nations involved (which are not always on the best terms) have agreed to cooperate to prevent further threats to the vultures.