In line with the celebrations of International Vulture Awareness Day (celebrated throughout September every year) we put the spotlight on the importance of vultures for the maintenance of ecosystems and human well-being.

While some animals may opportunistically feed on carrion, for vultures, this is the only source of food available. These birds can safely consume dead and decaying flesh because they have developed highly acidic stomachs—up to one hundred times more acidic than human ones!—where most bacteria cannot survive.

Owing to their scavenging efficiency, vultures are known as ecosystem sanitizers, as their removal of carcasses from the environment carries benefits for human health and well-being, particularly in parts of the world where access to expensive incinerators is limited.

However, one of the main threats to vultures is closely linked to their role as scavenging species - poisoning. Poisoning threatens the lives of these animals and comes from different sources: it can be unintentional—from secondary poisoning; poison baits; or veterinary drugs used on domestic livestock, such as Non-Steroidal Anti-Inflammatory Drugs, known as NSAIDs—where vultures are not the intended target. Poisoning can also be intentional, where vultures are deliberately poisoned, usually in Africa to obtain vulture parts for use in belief-based practices (e.g., traditional rituals).

Unintentional Poisoning: the Case of NSAIDs

NSAIDs are medicines widely used to relieve pain and reduce inflammation and fever. Commonly resorted to in human medicine, they have also become widely used in veterinary practice. There over 20 types of these drugs—aspirin, paracetamol and diclofenac are amongst the most well-known ones, in fact diclofenac is the most widely used NSAID in the world. Some of these drugs are toxic and deadly to vultures, who become exposed to them mainly through consuming the carcasses of cattle that have been treated a few days prior to dying.

The poisoning risk by NSAIDs represents a serious threat to vulture populations and, consequently, to human well-being. The severity of this threat is perfectly illustrated by a case-study in India during the mid-1990s. The vulture population in this country was reduced by more than 95% over only a couple of years during the second half of the 90s decade. At the time, diclofenac became widely available to farmers due to the entry into the national market of cheap generic brands after a patent long held by a pharmaceutical company expired. The veterinary use of diclofenac became widespread, and vultures died en masse after eating the unremoved carcasses of treated cattle.

As vultures died out, the scavenging services they provided disappeared too. With carrion remaining out in the open for long periods of time, the chances of pathogen and disease transmission to other scavengers, as well as to water sources increased. The cascading effects of the decline of vultures resulted in an extraordinarily large sanitation shock to human populations in India: human mortality increased by over 100,000 additional deaths per year, with associated mortality damages costed at USD 69.4 billion per year.

Due to their toxicity to vultures, various countries have since restricted the use of certain NSAIDs. For instance, Bangladesh, Cambodia, India, Iran, Nepal, Oman and Pakistan have fully banned the manufacture, sale and use of veterinary diclofenac. However, many other countries are yet to ban the use of toxic NSAIDs. This will be a crucial step in ensuring the safety of vulture populations around the world. Notably, there are vulture-safe NSAIDs that can be used in lieu of toxic ones, such as meloxicam or tolfenamic acid.

India Leading the Road to Safe Veterinary Use of NSAIDs

On 29 September 2024, a meeting was hosted by Bird Conservation Society, Gujarat (BCSG) in Ahmedabad, India to review vulture trends in Gujarat and across India, and discuss what still needed to be done. The Coordinating Unit of the Raptors MOU, represented by Mr Umberto Gallo-Orsi, delivered an opening address to the gathering of 300 birdwatchers, veterinarians and government officials:

From the meeting resulted an agreed call to action to action to promote the safety testing of veterinary NSAIDs for vultures ahead of licensing, in line with what is called for in CMS Resolution 11.15 (Rev.COP14):

© BCSG

© BCSG

Road Ahead

The veterinary use of toxic NSAIDs and the subsequent mass death of vultures have shown us that conserving these species results in high returns for human health and well-being, and the Gujarat meeting shows us that one relatively simple step, i.e. checking the safety of veterinary drugs before they are licensed, would go a long way to ensuring that vultures never go extinct.

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References:

Frank E. & Sudarshan A. (2023) The Social Costs of Keystone Species Collapse: Evidence From The Decline of Vultures in India. Working Paper No. 2022-165. University of Chicago.

Save Vultures (11 Oct 2024) Bird conservationists call for urgent action on veterinary drug regulation in India.