Is malaria the cause for decline in the wild population of the Indian White-backed vulture (Gyps bengalensis)?

Abstract

The populations of three species of Gyps vultures have shown a decline of more than 95% between 1988 and 1999 in the Indian subcontinent and are now classified as 'critically endangered'. The indiscriminate and widespread veterinary use of diclofenac has been implicated for the decline of the White-backed vulture (Gyps bengalensis) in Pakistan, India and Nepal. Similar trends in population decline as seen in the northern regions have also been recorded in Central and South India, but the cause for the decline was not investigated. Here we report a study carried out in a densely forested and sparsely populated region in Central India. An intracellular malarial parasite was identified from the tissues of both live and dead Whitebacked vultures. Further, amplification and sequence analysis of the consensus sequence of the mitochondrial small and large sub-unit rRNA genes indicated a 95-96% similarity with the mitochondrial sequence of Plasmodium falciparum (DQ642845) and other Plasmodium species. In addition, amplification and sequencing of a 502 bp fragment of the mitochondrial cyt b gene identified the haemoprotozoan with Plasmodium sp. AP70, an avian malarial parasite. During the course of this study we also rescued two terminally ill vultures with symptoms of malaria, and treatment with anti-malarials led to their recovery. None of the affected vultures had diclofenac residues, thus implying that malaria could be an additional cause for the decline for the White-backed vulture population.