Health officials in Goa on Tuesday said they were trying to track down 500 British holidaymakers who arrived in the Indian resort state after the outbreak of swine flu.
State epidemiologist Rajendra Tamba said they were planning to take throat swab samples of the tourists as a precautionary measure to prevent infection after a number of confirmed cases in Western countries.
India's health ministry has issued guidance that all passengers arriving from countries like Britain, the United States, France, Canada and New Zealand be screened at airports.
Just over 20,000 British tourists arrived in Goa in the last two weeks, including 500 since April 18, many of them on charter flights, state tourism officials said.
A quarantine ward has been set aside at a local hospital in the event of confirmed cases. Tamba said samples of throat swabs would be sent for testing at laboratories in Pune, about 190 kilometres (120 miles) from Mumbai.
Britain has two confirmed human swine flu cases -- a couple from Scotland who honeymooned in Mexico, which is the epicentre of the outbreak -- while there have been positive tests in other Western countries.