Health workers have begun culling of poultry in an attempt to combat a fresh bird flu outbreak in the country's eastern state West Bengal, officials said on Monday. State workers planned to destroy nearly 50,000 domestic birds in two districts where officials found infected poultry.

Culling began in a radius of five kilometers (3.1 miles) around the new area of infection. While 22,400 birds are to be culled in Raghunathganj-II, the culling target in respect of Jiaganj is 27,200 birds.

In January 2008, the H5N1 virus affected hit 13 of the state's 19 districts, including Murshidabad, bringing down poultry sales by more than 70 per cent.

The authorities had to cull more than 3.4 million birds in the state after the World Health Organization (WHO) described January's outbreak as the worst in India.

No humans in India are known to have caught the disease, which has killed at least 235 people worldwide according to the WHO.