The Delhi Animal Husbandry Department on Monday confirmed that all the samples sent to a laboratory in Bhopal have tested positive for bird flu or the avian influenza.
"Samples sent to Bhopal lab from Delhi test positive for bird flu," the Department's Director Rakesh Singh told .
The samples were sent to Bhopal's National Institute of High Security Animal Disease last week.
Besides Delhi, the disease has been confirmed in Kerala, Rajasthan, Madhya Pradesh, Maharashtra, Himachal Pradesh, Haryana, Gujarat, and Uttar Pradesh.
Avian influenza viruses have been circulating worldwide for centuries with four known major outbreaks recorded in the last century.
India reported its first outbreak in 2006.
In India, the disease spreads mainly by migratory birds flying to the country during winter months, from September–October to February–March.