"The two black-headed ibis died on Thursday and samples were sent to National Institute for High Security Animal Diseases (NIHSAD), Bhopal. The reports are back and they have tested positive for H5N1 avian influenza virus," an official said.
After the storks tested positive for bird flu on Friday, the zoo authorities had announced a temporary closure of the premises for the public.
A statement released by zoo director Sanjeet Kumar on Friday had mentioned that immediate action had been initiated in accordance with "Guidelines for Zoological Park of Action Plan for Preparedness, Control and Containment of Avian Influenza (revised-2021)" issued by ministry of fisheries, animal husbandry and dairying, to prevent its spread to other animals, birds and safeguarding staff at the zoo.
When asked about the two additional deaths, director Kumar said, "Intensive surveillance and biosafety measures are in place as per guidelines. There is no specific information to share at this stage."
The Delhi Zoo had last been closed in 2021 due to an outbreak of bird flu, and in 2016 before that.
The zoo official added, "All necessary precautionary measures are being taken, with close observation over all birds and animals. A close watch is being kept on mammals, especially big cats like lions and tigers who are vulnerable species during an outbreak."
"As per protocol, we will be keeping a close watch on the situation and regular random testing of birds will be done for the next 21 days, provided there are no deaths in between. After the deaths stop, tests are conducted every 15 days for at least three times to confirm that the zoo is completely virus free. If there are deaths in between, then that timeline will rest accordingly and we will take a call depending on the situation," the official added.
Meanwhile, the zoo remains closed for visitors until further notice.