PATNA, March 1 -- The Sanjay Gandhi Biological Park, popularly known as Patna zoo, has been closed to visitors till March 7 as a precautionary measure following confirmation of H5N1 avian influenza in the state capital, said officials on Saturday. An official of the dairy, fisheries and animal resources department said the advisory to shut the zoo was issued after around 5,000 poultry birds were culled last Wednesday at the Bihar government's poultry research and training centre under Bihar Animal Sciences University (BASU) in the Kaushal Nagar area of Chitkohra locality in Patna. "We do not want visitors to unknowingly carry the H5N1 virus through their footwear to the Patna zoo. Extra caution is necessary as the birds housed there fall under Schedule I and II of the Wildlife (Protection) Act, 1972, which accord the highest levels of legal protection. Quarantine is the only option to safeguard these species," the official said. Authorities have intensified control and containment operations across affected areas in Patna. Cases of bird flu in crows were reported from Kankerbagh J-sector and near the Patna high court, while highly pathogenic avian influenza was confirmed in poultry birds at Chitkohra. Intensive fogging and sanitisation drives have been carried out within a 1-km radius of the epicentre of crow and poultry bird deaths. Antiviral agents and disinfectants, including sodium hypochlorite and glutaraldehyde, are being sprayed as part of the containment protocol. However, samples collected from crows in IGIMS and AG Colony tested negative for bird flu and instead showed the presence of E. coli (Escherichia coli) bacteria. Approximately 5,000 poultry birds, 10,000 eggs and 550 kg of poultry feed were destroyed during the culling operation at Chitkohra last Wednesday. The culled birds and eggs were buried in three large pits dug at the site and covered with lime and bleaching powder. The area has been declared a prohibited zone. Officials said nearly 4,500 poultry birds had died at the farm between February 11 and 24, prompting authorities to initiate culling after laboratory confirmation of H5N1. Samples from the affected poultry were sent on February 11 to the Regional Disease Diagnostic Laboratory in Kolkata, which confirmed the presence of the H5N1 virus....