(Adds top sanitary official denial of bird flu case) ST PETERSBURG, Russia, Dec 19 (Reuters) - One of Russia's main zoos has closed down after the deaths of two geese sparked a bird flu scare, but the top sanitary official said on Tuesday that tests had not confirmed the outbreak of the disease. "Samples taken from the dead geese did not test positive for bird flu," chief sanitary expert and head of Russia's consumer rights watchdog Gennady Onishchenko told Interfax news agency. Zoo staff had also been given health clearance after examination, he added. The zoo in St Petersburg, one of Russia's oldest, officially refused to explain its unscheduled closure on Monday night, but health officials linked it to the discovery of the two dead birds. The zoo has about 800 birds in all. A notice at the zoo said it would remain closed until the end of the year. "They did not die from bird flu," a local expert on bird flu, who had knowledge of tests carried out on the dead geese, told Reuters earlier. "The birds had been vaccinated against bird flu." Bird flu remains essentially an animal disease but it has infected more than 250 people worldwide since late 2003, killing more than 150, according to the World Health Organisation. Experts fear the virus could mutate into a form that is easily transmissible between humans and spark an influenza pandemic, killing millions of people.
