Last week the death count from the mystery disease was over 15,000 birds, reported the Times of India.

Authorities had previously said that it could be a new disease hitting the poultry farms at Injapur village, as helpless farmers said that over 80 per cent of the stocks had perished in one of the three poultry sheds there.

"These birds appear active but all of a sudden they start shivering with high fever and drop down dead. What's surprising is that there is no change in their feed and water intake," said B Krishna Reddy, owner of the Injapur poultry farm.

The Bhopal-based High Security Animal Disease Laboratory (HSADL) confirmed last week that it was not a case of bird flu.

Newcastle disease, also known as Ranikhet in India, is listed as a notifiable disease. Top officials in the animal husbandry department said that the infection was confirmed through tests conducted by a Veterinary Biological and Research Institute (VBRI) team.

"In their preliminary findings, the VBRI team concluded that the outbreak was due to Ranikhet disease. It is a vaccine preventable disease, characterised by high mortality rate and respiratory distress.

"We have advised the poultry owner to administer Lasota vaccine," said Dr Y Thirupathaiah, director of the animal husbandry department.

Dr Thirupathaiah added that further tests on the bird samples are still under way and a complete picture on the disease would require two more days.

Owner B Krishna Reddy commented: "I had vaccinated my entire flock of 50,000 birds against Ranikhet last month. So when I was telephonically informed about the outbreak as Ranikhet, it came as a surprise to me," he said, adding that he has already started the inoculation process on his younger flock of birds.