New Delhi, Sept. 15 -- The Environment Ministry today said test results of all the samples collected from the Delhi Zoo since September 1 have been found to be negative for H5N1 Avian Influenza.

No new cases of water bird mortality or symptoms suggestive of avian influenza in other zoo animals have been reported, it said.

However, treading cautiously, the Delhi Zoo will remain closed for visitors until further notice, the Ministry said in a statement. It will be reopened based on existing protocols and guidelines, said the Ministry.

The Delhi zoo which was placed under enhanced surveillance earlier this month following the death of water birds-some of whom tested positive for the H5N1 virus-has since implemented intensive sanitation and ...