The Indian Veterinary Research Institute (IVRI), Bareilly, on Thursday confirmed avian botulism — a neuro-muscular illness caused by a toxin which is produced by a bacterial strain — as the reason for mass mortality of birds, including migratory species from Northern Asia, at Sambhar Lake in Rajasthan.
The laboratory tests conducted on the samples of carcasses collected from the lake confirmed the disease infecting the birds, the probability of which was earlier stated by veterinarians in the State. The illness, caused by a bacterium called Clostridium botulinum, affected the nervous system of birds, leading to flaccid paralysis in their legs and wings and neck touching the ground.
More than 18,000 carcasses of birds have been removed from the lake and its catchment area so far, raising concern among environmentalists and ornithologists. The scientists at IVRI found the samples infested with maggots of third stage with a clear indication that the avian mortality had occurred over a period of time.
Animal Husbandry Minister Lal Chand Kataria said the IVRI report had approved the regimen of treatment adopted for birds recovered from the lake’s shores. “The rescue centres established near the lake have treated 735 birds, of which 368 are alive and 36 have been released to their natural habitat,” he said.
Located 80 km south-west of Jaipur, Sambhar Lake is India's largest inland saline water body and has been designated as a wetland of international importance, attracting thousands of migratory birds during winter.
Avian flu ruled out
A Bhopal-based laboratory had earlier ruled out avian flu as the cause of deaths of birds after examining the viscera. The post-mortem of two bird carcasses by a Bikaner-based research organisation had concluded that bacterium Clostridium botulinum had entered from the soil into the meat of some dead birds.