WA5 Wildlife Toxicology: Forensic Approaches
203 Oregon Ballroom
8:00 AM - 12:00 PM, Wednesday
() Veterinary use of the anti-inflammatory drug diclofenac as the cause of vulture mortality and declines in Pakistan.
Oaks, J1, Meteyer, C2, Rideout, B3, Shivaprasad, H4, Gilbert, M5, Virani, M5, Watson, R5, Khan, A6, 1 Washington State University, Pullman, WA, USA2 National Wildlife Health Center, Madison, WI, USA3 Zoological Society of San Diego, San Diego, CA, USA4 University of California at Davis, Fresno Branch, Fresno, CA, USA5 The Peregrine Fund, Boise, ID, USA6 Ornithology Society of Pakistan, Dera Ghazi Khan, Pakistan
ABSTRACT- Since 2000, high mortality rates in White-Backed Vultures (Gyps bengalensis) in Pakistan have led to catastrophic population declines of these birds. The majority of these deaths (
85%) were associated with the clinical syndrome of visceral gout and acute renal failure. The microscopic renal lesions were most compatible with an acute toxic etiology. Testing ruled out toxic levels of heavy metals known to be associated with renal failure in birds, including cadmium, lead and mercury. In addition, toxic or deficient levels of other heavy metals, including arsenic, copper, iron, manganese, molybdenum and zinc were not detected. There was no evidence of acute intoxication by organophosphate, carbamate, or organochlorine pesticides. Viruses or other pathogens were not isolated. Molecular biology studies for avian influenza and infectious bronchitis virus, two viruses recognized as renal pathogens in poultry, were negative. With the exclusion of known causes of renal disease and/or acute death in birds, the studies were directed at novel toxins. Since the primary food source for the vultures in Pakistan are domestic livestock, we hypothesized that veterinary drugs may be associated with kidney disease in the vultures. We conducted a survey of veterinarians and veterinary drug retailers in the region to identify drugs that might be potentially nephrotoxic, commonly used and new to the market. One drug, diclofenac, met all these criteria. Diclofenac is a non-steroidal anti-inflammatory drug used to treat most types of livestock in Pakistan. Tissue samples from 25 vultures with renal failure and 13 vultures without renal failure (control birds known to have died of other causes) detected a 100% correlation between residues of diclofenac and renal failure. Experimental exposures of vultures to diclofenac through treated buffalo reproduced renal disease and tissue residues. These findings implicate diclofenac as the cause of vulture declines in southern Asia.
Key words: diclofenac, vulture, renal failure, veterinary