Title
Rate of decline of the oriental white-backed vulture population in India estimated from a survey of diclofenac residues in carcasses of ungulates
Author(s)
Green R.E., Taggart M.A., Senacha K.R., Raghavan B., Pain D.J., Jhala Y., Cuthbert R.
Published
2007
Publisher
PLoS ONE
Abstract
The non-steroidal anti-inflammatory drug diclofenac is a major cause of the rapid declines in the indian subcontinent of three species of vultures endemic to South Asia. The drug causes kidney failure and death in vultures. Exposure probably arises through vultures feeding on carcasses of domesticated ungulates treated with the drug. However, before the study reported here, it had not been established from field surveys of ungulate carcasses that a sufficient proportion was contaminated to cause the observed declines. We surveyed diclofenac concentration in samples of liver from carcasses of domesticated ungulates in India in 2004-2005. We estimated the concentration of diclofenac in tissues available to valtures, relative to that in liver and the proportion of vultures killed after feeding on a carcass with a known level of contamination. We asessed the impact of this mortality on vulture population trend with a population model. We expected levels of diciofenac found in ungulate carcasses in 2004-2005 to cause oriental white-backed vulture population declines of 80-90 per year, depending upon the assumptions used in the model. This compares with an observed rate of decline from road transect counts, of 48% per year in 2000-2003. The precision of the estimate based upon carcass surveys is low and two types of estimate were not significantly different. Our analyses indicate that the level of diclofenac contamination found in carcases of domesticated ungulates in 2004-2005 was sufficient to account for the observed rapid decline of the oriental white-backed vulture in India. The methods we describe could be used again to assess changes in the effect on vulture population trend of diclofenac and similar drugs. In this way, the effectiveness of the recent ban in India on the manufacture and importation of diclofenac for veterinary use could be monitored. © 2007 Green et al.
Keywords
diclofenac; accuracy; animal tissue; article; bird; carcass; cause of death; controlled study; domestic animal; dose response; drug determination; drug exposure; drug liver level; drug manufacture; drug tissue level; feeding; India; kidney failure; mortality; nonhuman; ungulate; veterinary medicine; Gyps africanus; Ungulata
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PUB12094