In the 1990s, Indian farmers started using a cheap painkiller for cattle, which tragically led to a massive decline in the vulture population—down from 50 million to just a few thousand. These vultures were crucial for cleaning up animal carcasses and preventing the spread of deadly diseases. With their numbers dwindling, carcasses began to rot, leading to the proliferation of disease-carrying feral dogs and contaminated water sources. This ecological disaster has been linked to around 500,000 human deaths and $69 billion in economic losses due to the health impacts and increased disease spread. The story is a stark reminder of how disrupting one part of an ecosystem can have catastrophic consequences.

Scientists claim that in the 1990s, eager Indian farmers adopted a painkiller for their cattle, which resulted in the unintentional death of 500,000 people and enormous financial losses. These losses were not caused by harm to the cattle, but rather by the vulture population, which historically ate animal remains before they rotted and became disease vectors reports CBS News.

The patent on the painkiller diclofenac was revoked in the early 1990s, making it widely accessible and affordable for India’s enormous agricultural industry. It is used by farmers to cure a variety of ailments in their cattle. However, vultures die from exposure to even minute amounts of the medication. The number of domestic vultures in India has decreased from a staggering 50 million to just a few thousand since it was first widely used. A study released by the American Economic Association states that this has had a significant negative impact on human population density, underscoring the scavengers’ essential role in the food chain.

For millennia, vultures have played a vital role in India’s ecosystems. In their paper “The Social Costs of Keystone Species Collapse: Evidence From The Decline of Vultures in India,” the authors claim that vultures are a type of “keystone species” that are indispensable to an ecosystem.

As the only scavengers that eat carcasses, they do it with remarkable efficiency, gobbling up the leftovers and leaving no trace of harboring illness. Before their population was completely wiped out, the study’s authors estimate that India’s vultures would have eaten at least 50 million animal carcasses annually.

By doing this, they stopped the farm animals’ corpses from decaying and the spread of harmful bacteria and other illnesses to human populations.

“In a country like India with prohibitions on eating beef, most cattle end up turning into carcasses,” Anant Sudarshan, an associate professor of economics at the University of Warwick in England, who co-authored the study, told CBS News. “Vultures provide an incredible disposal service for free. … A group of vultures takes about 45 minutes to turn a cow carcass into bone.”

Due to their voracious appetites, vultures were also able to control the numbers of other scavengers that could spread rabies and other diseases, like wild dogs and rats.

Farmers started administering diclofenac to their cattle and other livestock in 1994. The medication causes kidney failure and death in vultures, who consume the carcasses of animals administered the analgesic; in the following ten years alone, the vulture population dropped from 50 million to 20,000.

Farmers began discarding their dead cattle in nearby bodies of water when vultures were absent, which led to water contamination and provided an additional route for diseases to infect people.

By mapping vulture habitats with health data from over 600 Indian districts, Sudarshan and research co-author Eyal Frank, an environmental economist at the University of Chicago Harris School of Public Policy, investigated the effects of the sharply declining vulture population on human health. According to their research, there could be a connection between the decline in vulture numbers and the 100,000 annual human fatalities that occurred between 2000 and 2005.

Additionally, it displays economic losses estimated at $69 billion annually, most of which are related to early human fatalities brought on by the decline in the scavenger population.

Their research indicates that the infections that might have been prevented by a healthy vulture population instead spread and caused these deaths. Along with an increase in the number of stray dogs during that period, rabies cases also climbed, as did the quantity of bacteria found in numerous local water sources.

“India is now the largest center of rabies in the world, as the feral dog population has grown dramatically,” Sudarshan told CBS News.

The study’s authors predicted that in the upcoming years, both the expenses of medical care and the spread of disease and mortality that occur from it will persist in the absence of a significant vulture rebound.

While diclofenac was banned for use in veterinary medicine in India in 2006, Sudarshan stated the prohibition has to be implemented much more forcefully. To increase vulture populations, he and Eyal have advocated for additional money for conservation. However, they have cautioned that, even if the Indian government makes a significant effort, it will take the species at least ten years to recover to the amount that is necessary because they are “slow reproducers.”

Instead of bringing the vultures back, Sudarshan suggested that India build a network of incinerators across the nation. However, the estimated annual cost of doing so is approximately $1 billion, and the incinerators would consume a significant amount of energy and contribute to significant air pollution, which is already a major issue for India.

“So, it makes more sense to bring back the natural way of dealing with the millions of animal carcasses that India produces each year,” he said.

He added that since the “vultures began dying in the 1990s,” work needs to get done immediately. After three decades, India has not taken any action.

About $3 million is spent annually by the government to protect India’s indigenous tigers. Even if vultures aren’t as popular with tourists, Sudarshan said there’s a bigger issue about “the basis of our conservation policy.”

“Our paper shows that the cost of losing them [vultures] is about $69 billion a year, which is far higher than any benefits the tiger” brings, he said, adding: “We need to think from a cost-effectiveness point of view and growth view, how should we pick species to conserve?”

“Understanding the role vultures play in human health underscores the importance of protecting wildlife – and not just the cute and cuddly,” said his co-author, Frank. “They all have a job to do in our ecosystems that impacts our lives.”

Previously, GreatGameInternational reported that as of the most recent published count from 2020-2021, there were 1,093 sewage treatment plants with operational capabilities of just 26.9 billion liters of wastewater per day, indicating that only 37% of India’s wastewater is treated.