( dpa ) - Authorities in India's eastern West Bengal state were set to reach their target of culling 2.9 million poultry on Saturday in an attempt to contain an outbreak of bird flu, while a sick health worker was being closely monitored, media reports said.
"The man who fell sick after returning from culling ... is under special observation at a hospital. His samples have been sent for tests. But so far we have not found anything to suggest he is infected," West Bengal Health Department official RS Shukla was quoted as saying by IANS news agency.
Avian flu has been confirmed in 14 of West Bengal's 19 districts in an outbreak described as the most serious so far in India by the World Health Organization (WHO).
India has seen two previous outbreaks of avian flu but no human infections were reported.
Shukla said media reports of suspected human infection in the current outbreak were incorrect.
"No one has been quarantined. There is only routine surveillance of the people engaged in culling operations. Many of them are anyway falling sick due to the intense cold," Shukla said.
"We are maintaining records of people falling sick. If there is anything indicative of human infection we will take necessary measures. But so far all 18 tests we have carried out have proved negative," he said.
The H5N1 virus is highly contagious among birds but is difficult to pass to humans, who usually become infected through close contact with infected birds or contaminated surfaces.
Health experts fear, however, that the virus could mutate into a form that could easily pass between humans, setting off a global pandemic that could kill millions.
The WHO has confirmed at least 223 deaths in 12 countries in Asia and Africa up to January 29.
West Bengal reported the outbreak of bird flu on January 15, while neighbouring Bangladesh announced an outbreak on January 3.