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Sunday, November 25, 2018


By on Sunday, November 25, 2018
Populations of three resident Gyps species (Indian white-backed vulture Gyps bengalensis, Indian vulture Gyps indicus, and Slender-billed vulture Gyps tenuirostris) in India have decreased by more than 90% since mid 1990s, and they continue to decline. Experimental studies showed the mortality of vultures to be due to renal failure caused by diclofenac, a non-steroidal anti-inflammatory drug. India, Pakistan, and Nepal banned the veterinary usage of diclofenac in 2006 to prevent further decline in vulture population. 
 This was confirmed after a study was carried out to know the current status of the impact of diclofenac on vultures in India. Between 2011 and 2014, 44 vultures comprising two species, namely Indian white-backed vulture (32) and Himalayan griffon Gyps himalayensis (12) were collected dead from Gujarat, Assam, and Tamil Nadu on an opportunistic basis. Kidney and liver tissues and gut content were analyzed for diclofenac. Of the 32 dead white-backed vultures analyzed, 68.75% of them had diclofenac ranging from 62.28 to 272.20 ng/g. Fourteen white-backed vultures had diclofenac in kidney in toxic range (70-908 ng/g). Of 12 Himalayan griffon studied, 75% of them had diclofenac in the range of 139.69 to 411.73 ng/g. Himalayan griffon had significantly higher levels of diclofenac in tissues than Indian white-backed vultures. It is possible that 14 of 29 white-backed vultures and 9 of 12 Himalayan griffons included in this study died due to diclofenac poisoning (K Nambirajan 2018). Yet in another studies the effectiveness of the ban of diclofenac was carried out as this drug was banned in the month of May 2006. To evaluate the effectiveness of the ban surveys of > 250 veterinary and general pharmacies in 11 Indian states from November 2007 to June 2010 were undertaken. Twelve different classes of non-steroidal anti-inflammatory drugs (NSAIDs) were purchased from 176 pharmacies. Other than meloxicam (of negligible toxicity to vultures at likely concentrations in their food), diclofenac and ketoprofen (both toxic to vultures), little is known of the safety or toxicity of the remaining nine NSAIDs on sale. Meloxicam was the most commonly encountered drug; sold in 70% of pharmacies, but 50% of the meloxicam brands sold had paracetamol (acetaminophen) as a second ingredient. Diclofenac and ketoprofen were recorded in 36 and 29% of pharmacies, respectively, with states in western and central India having the highest prevalence of diclofenac (44–45%). Although the large number of manufacturers and availability of meloxicam is encouraging, the wide range of untested NSAIDs and continued availability of diclofenac is a major source of concern. Circumvention of the 2006 diclofenac ban is being achieved by illegally selling forms of diclofenac manufactured for human use for veterinary purposes (Richard Cuthbert and Ruchi Dave 2011). Therefore,we can reach to a safe conclusion that despite we have a ban on the drug its ban is neither enforced nor its circumvention is prevented successfully.
Long considered harbingers of death, vultures, nature’s scavengers, are perched on the brink of extinction themselves. Efforts are being made in India to bring them back. But with mixed reports of success, we are a long way off yet. According to our census, we had estimated 40 million vultures in the 1990s, which declined by 99.9% in 2007. By 2015, the vulture population showed some sign of improvement but still very critical and their population is still very small, just a few thousand. As per the Ministry of Environment, Forest and Climate Change (MoEFCC), there are nine species of vulture found in India. Out of these, four are critically endangered and require urgent attention. The population numbers for these four are still dropping at an alarming rate of 97-99 percent.
In an effort to save the existing population and increase the numbers, the MoEFCC launched a Vulture conservation India in 2006. Its primary recommendations included a ban on diclofenac, a common veterinary drug for cattle that proves fatal for vultures, and establishment of breeding centres modelled on the Jatayu Conservation Breeding Centre (JCBC) in Haryana.
Unfortunately, not all has gone according to plan. Although seven new breeding centres were established, JCBC remains the only one with successful breeding of the endangered vulture species in captivity, ready to be introduced in the wild. The Nehru Zoological Park in Hyderabad started with five vultures (two males and three female), and later procured six more birds (five male and one female). However, only one pair has mated till date. All attempts have led to unfortunate ends. Eggs have fallen from the nest, proven to be infertile, and when hatched, the chick did not survive. The fact that vultures are slow breeders and lay only one egg at a time proves to be a further impediment to the process. The Hyderabad Park is not the only one. Plans for a new breeding centre in Maharashtra folded up after rounds of plans and discussions due to lack of space and funds. Similar challenges have been reported by Rani Vulture Breeding Centre as well. About 50 vultures died in the Pani Dihing Wildlife Sanctuary in 2015, and 32 birds were found dead this year in March. Although the centre is ready to release 30 adults and sub-adults in the wild, their plans are getting delayed due to the still-available vials of diclofenac.
At the Jatayu Conservation Breeding Centre (JCBC), in Pinjore in Haryana, near Chandigarh, scientists are training eight captive born white-backed vultures to live in the wild. Ornithologists at the centre located within a wildlife sanctuary are preparing the second generation of vultures born and bred at the centre for a soft release by March, when they should get the imported satellite transmitters that will be tagged on to the birds to track their movement. The soft release entails taking the captive-bred birds to a bigger area, where they can mingle with wild vultures. The eight vultures will then be monitored for two years and if no drug-related mortality is found in them, the scientists will release another 20 pairs of vultures into the wild. Vultures are big and slow-breeding birds with a lifespan of 40 to 45 years. They pair for life and start laying eggs when five to six years old, although only about half of them reach adulthood. Birds less than a year old were collected and it five to six years before actual breeding was started. The success story of this centre will certainly be neutralized with the diclofenac being available in the market in one form or the other.
We all know that drug-related mortality has been the principal cause of wiping out almost all of India’s vulture population but we are not able to contain it. Until a few decades ago, Indian white-backed vultures were the largest group of scavenging birds on the planet. Today, they have the distinction of being the species with the most rapid decline in population in recorded history. Dr Vibhu Prakash(BNHS) While working on his thesis at Keoladeo National Park in Rajasthan, kept track of the number of vulture nests found that there were 353 nests in a small area of 29 square km in 1987 but in 1997 when he came back he could only find 150 nests. In the year 2000 he found no nest in the sanctuary area. After Dr Prakash flagged the disappearance of the vultures, scientists found out what was killing them: the birds were dying in large numbers due to kidney failure. The internal organs of dead vultures were covered with a white paste of uric acid. The cause of the kidney failure was a mystery that was solved by a team of ornithologists led by a US scientist. They found that diclofenac, a painkiller drug used to treat sick cattle, poisoned the vultures that fed on the carcasses of these animals.
Diclofenac is toxic to vultures even in small doses, causing kidney failure. Those results in uric acid accumulating in the birds' blood and crystallizing around their internal organs, a condition called visceral gout. In Europe, diclofenac has been approved for veterinary use since 1993. In 2014, the European Medicines Agency acknowledged that vultures are at risk of consuming residues of the drug in dead livestock, but did not recommend banning. In 2015 the European Commission decided to follow the EMA’s recommendation, leaving it to EU members to prevent diclofenac-laced carcasses from entering the food chain. But in 2012, a dead vulture discovered in Spain was found to contain high levels of a similar drug called Flunixin indicating that another non-steroidal anti-inflammatory drug in veterinary use in Spain which should not have been in the food chain.The impact of diclofenac on the vultures was devastating. According to mathematical models prepared by Cambridge University showed that the presence of diclofenac in even less than 1% of the carcasses in the country would be enough to endanger the entire vulture population. Diclofenac residue was found in 10% of the carcases before India banned the drug. In 2015, the government banned multi-dose vials of diclofenac and restricted the ampule size for human use to 3 ml. However, the drug is said to be still used illegally and even today, about 2% of the carcases are estimated to carry diclofenac. In one of the studies carried out about the impact of dosage of  toxicity of diclofenac to a Eurasian (Gyps fulvus) and an African (Gyps africanus) species, neither of which is threatened. A dose of 0.8 mg kg−1 of diclofenac was highly toxic to both species, indicating that they are at least as sensitive to diclofenac as G. bengalensis, for which we estimate an LD50 of 0.1–0.2 mg kg−1( Gerry E Swan 2006)
Vultures play a critical role in keeping the countryside clean. Along with lesser scavengers such as jackals, hyenas, dogs, crows and kites, vultures play a key role in disposing of the carcasses of wild and domestic dead animals. Their sheer numbers ensured that no decaying carcasses remained long enough to spread diseases and contaminate the soil and water. In the absence of vultures, the dead body of cattle acts as media for the bacteria and the fungus to grow and multiply in millions and go into the soil, water and cause diseases. The vanishing vultures also led to an increase in the numbers of other animals of prey animals like rats and dogs. We have observed the growth of an entire generation of stray dogs that feeds only on carcasses and this increases the risk of spread of rabies, and livestock borne diseases like anthrax.
Apart from captive breeding, BNHS and other entities have implemented a range of measures to save the vulture. These include the setting up of vulture safe zones, which are diclofenac free areas with a radius of 100 km and at least one nesting colony. Work is going on to set up eight such zones in India. While the use of safe veterinary drugs is continuously advocated, carcass sampling is undertaken across the country to monitor for the presence of diclofenac. Forest departments in some states and a few NGOs have taken up initiatives for vulture conservation. The Gujarat forest department carries out a vulture census every two years. The survey showed the number of vultures declining to 1,065 in 2010 from 1,431 in 2007. The latest census completed in May is yet to be made public.  The Maharashtra forest department has set up vulture ‘restaurants’ in Gadchiroli, Nashik and Raigad. These ‘restaurants’ are set up mainly to provide enough and safe food for vultures.
Still, ornithologists are hopeful about bringing back the vultures, with enough examples of birds and animals brought back from near extinction in India and elsewhere. The pygmy hog, the smallest wild pig in the world that’s found in the grasslands of the Terai region, was thought to be extinct. With conservation efforts, their numbers have now increased to a few hundred. The Mauritius Kestrel was once considered the world’s rarest bird, with only four known to exist in the wild by 1974. However, with conservation, their numbers have increased to a few hundred now and the bird is out of danger of extinction, although still h classified as endangered.


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