A young girl herds a small group of cows and goats in the Shivalik hills of northern India. As she passes under a grove of tall pines, a downy head with a huge beak pokes out from a tree and watches intently.
This is a white-backed vulture. Before the girl was born, there were tens of millions of this species of vulture in India, and thousands would nest in these hills. But in less than 10 years, the white-backed vulture has declined by 99,7%.
Three species are in a tailspin towards extinction, the most catastrophic decline of any bird since the passenger pigeon and the dodo.
The white-backed vulture, Gyps bengalensis, the long-billed vulture, Gyps indicus, and the slender-billed vulture, Gyps tenuirostris, could all be extinct within three years. It is an ecological tragedy, but it is just being realised that it is also a grave threat to public health.
Only this year, a non-steroidal, anti-inflammatory drug called diclofenac, a cheap and effective cure for many ailments in livestock, was identified as a major contributing cause of the massive crash in the vulture population. Vultures can reduce a large animal to a pile of clean bones in an hour, but if the carcass carries diclofenac, the vultures will get kidney failure, visceral gout and die within 30 days.
But will the disappearance of vultures from the ecology really have a major impact on human health? The link between vulture decline and zoonotic disease (disease transmitted to humans from animals) has yet to be explored by the World Health Organisation (WHO), and a spokesman at the organisation says the zoonotic disease problem has been ”overstated”.
David Houston, professor of zoology at Glasgow University and an expert on vultures, believes the demise of vultures could be serious. ”In India, livestock are kept in townsand villages. They are an integral part of the urban environment. I have seen dead buffalo rotting into a stinking pool of goo just metres from where children are playing. This would not happen with a healthy vulture population.
”Although there is no good data,” says Houston, ”we know there is a risk of bacterial contamination from rotting animals into shallow wells. Flies lay eggs on carcasses and then land in kitchens on food, spreading food poisoning and dysentery.” Houston also attributes the absence of vultures to the increase in wild dogs. As the birds have declined, the population of feral dogs has increased. Statistics are sketchy but some accounts claim its numbers soared to 25m in 2002. At one carcass dump in Rajasthan, before the decline, there were 1 500-2 000 vultures and 60 dogs. Now there are no vultures and 1 200 dogs.
Rabies is endemic to India and 96% of cases result from dog bites. According to WHO, 81% of the global deaths from rabies occur in India, where more than 30 000 people die each year from the disease. This figure could be even higher because of the many unreported deaths in rural areas. Andrew Cunningham, head of wildlife epidemiology for the Zoological Society of London, has been following the vulture crisis since its detection and is concerned about the danger surrounding the dog population explosion.
”Dogs are a direct problem for people because of the availability of food. In many places, social interaction between dogs and humans has broken down; the dogs are wild and will attack people and wildlife,” he says.
”Apart from rabies, which can be passed on to a large number of species including livestock, dogs carry endemic diseases such as canine distemper and mange. These are a threat to many rare and endangered species of Indian wildlife such dhole [Indian wild dog], gyr lions [Asiatic lion] and tigers. Plague is endemic to India and rats are also increasing,” he adds.
Added to these problems is the spread of anthrax. Animal anthrax is endemic in the largely unprotected and uncontrolled livestock population in India and can spread to people. The speed with which vultures clean up cattle carcasses prevents the spread of the disease. Without them, more anthrax spores are expected to infect the soil and remain viable for decades.
Alternative methods of carcass disposal are not easy. People without access to heavy machinery find it hard to destroy big carcasses. Using petrol or kerosene is expensive for subsistence farmers, as is using scarce wood.
Meanwhile, people who made a living from skinning carcasses for leather and selling bones for fertiliser or gelatine after the vultures have picked them clean have been badly hit.
But the most profound cultural adjustment is being felt by the Parsee community who traditionally offer up their dead for ”sky burial” – to be eaten by vultures.While traditionalists are desperately trying to find ways to keep vultures, others are experimenting with new ways of cremation.
Last month, scientists, conservationists and government officials came up with a vulture rescue planthat recommended the banning of diclofenac. The only way to save the vultures, it was agreed, was to begin an immediate captive breeding programme throughout the range states of the three vulture species.
But the process is long and it is unlikely that any birds would be released into the wild until 2030. Meanwhile, the vultures’ decline carries serious consequences for public health.