Sunday, May 17, 2009

Flu with pandemic potential in India

- Patient who flew in from New York quarantined, search on for other passengers

New Delhi, May 16: The new influenza virus rapidly spreading across the world has surfaced in India with health authorities confirming the infection in a man who flew into Hyderabad from New York after a stopover in Dubai.

Doctors at Hyderabad airport quarantined the man and shifted him to an isolation facility minutes after he landed on May 13 because he had a fever, health ministry officials said today. Tests on his nasal and throat swab samples have shown that he is infected with the same strain of the H1N1 influenza virus that has caused illness in more than 8400 people across 36 countries over the past month.

He has been administered the anti-viral drug oseltamivir, and he no longer has fever. But health officials are scrambling to track down the other 156 passengers who had shared aircraft cabin space with him from Dubai to Hyderabad.

“We still have no evidence of domestic transmission of the virus,” Vineet Chawdhry, joint secretary in the ministry of health told The Telegraph. “Containment [of the virus] will remain a relevant strategy for us.”

State health staff are trying to find all passengers from the flight within the next 24 to 48 hours and examine them for signs of respiratory illness. The incubation period of the virus is believed to be about seven days. Health officials want to ensure that any other passenger who might have picked up the infection is also appropriately isolated and treated to prevent further spread of the virus.

At a closed-door meeting this morning, senior health officials and medical researchers brainstormed about India’s containment options if domestic transmission of the virus begins to occur.

“We’ve already alerted disease surveillance units in all states to look out for unusual clusters of influenza-like illness in communities,” Chawdhry said. “We’re also hoping private medical practitioners who notice clusters of such illness will inform us.”

One option would be to cordon off an area where we observe clusters,” a senior official who attended the meeting told The Telegraph.

The strategy would be to issue advisories to people in the affected area to stay at home, shut down schools and markets in the affected area to reduce the risk of the virus spreading even more into other communities, the official said. “But we aren’t at that point yet,” the official said.

A zone of 3km to 5km around a cluster of cases may be defined as an affected area

A study of the behaviour of the virus suggests that for every 10 patients infected by this H1N1 strain, there are likely to be 12 to 16 new, secondary cases. The virus appears to be associated with a mortality rate of 4 per 1000, and scientists believe that the severity and outcome of the infection depends on a number of factors — the virus, the patient’s health condition, and treatment.

India’s disease surveillance system has never formally looked for spikes in influenza, although limited city-based surveillance has shown that seasonal peaks of influenza occur in India just as they do in North America and Europe. Virologists have said the arrival of H1N1 in India was inevitable. An international science team cautioned earlier this week that the virus is showing patterns of spread similar to the flu pandemic of 1957 that killed 2 million worldwide.

“The problem is our disease surveillance system isn’t geared to pick up spikes in respiratory illnesses,” said T Jacob John, former head of virology at the Christian Medical College, Vellore. “The private sector which sees 70 per cent of illnesses should be a major contributor to surveillance, but the government’s surveillance system has no hold on private medical practitioners,” John said.

“If the virus slips through the airport surveillance, it could then begin spreading at an unexpected place,” he said. “And the first few cases of domestic transmission might be missed.”

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