New Delhi, June 2: A mother and her child incubating the new H1N1 influenza virus flew into Chennai from the US and travelled to Coimbatore before they were found to be infected, exposing predicted gaps in airport health surveillance.

The 34-year-old woman and her five-year-old boy walked through the Chennai airport health surveillance on May 28, although the boy had fever before leaving the US, and reported on their own to a health facility in Coimbatore.

Tests on their throat swab samples revealed they were infected with the new H1N1 virus that has spread to 62 countries over six weeks, infected more than 17,000 people, and killed at least 115.

Doctors in Coimbatore have administered the anti-viral drug oseltamivir to the woman and the boy. They currently have no fever, health authorities said tonight.

However, health authorities are keeping watch on their family contacts and trying to trace all passengers and crew of the domestic Kingfisher flight — IT 2901 — that the mother and child had boarded to fly to Coimbatore on May 28.

Sources said the mother and the child had “no symptoms” when they had presented themselves at the Chennai airport surveillance station.

But if the child had fever before leaving the US, as claimed by health authorities, this information should have been available to the airport surveillance officers.

Public health researchers have cautioned that the airport surveillance system is unlikely to prevent the virus from entering India and that surveillance should focus on looking for local clusters of flu infections.