Second wave of flu likely in two months

By: APINYA WIPATAYOTIN

Published: 16/05/2009 at 12:00 AM

Newspaper section: News

Thailand should prepare for a second wave of the (A) H1N1 influenza, which could occur as early as July, warns a viral expert.

The pattern of the (A) H1N1 outbreak is similar to other flu pandemics such as the Spanish flu in 1918, which killed 20 million people worldwide, said Dr Thirawat Hemachudha, director of the World Health Organisation's Collaborating Centre for Research and Training on Viral Zoonoses.

Scientists say there are four steps which indicate whether the disease can cause a pandemic. They are that it is a new strain of virus, humans can contract it, it is non-seasonal, and the virus can spread quickly and widely.

''The (A) H1N1 flu has already passed the first three steps. We'll just wait and see when the last step explodes. The current situation is like a warning sign, reminding us that the big wave is coming,'' he said.

''According to scientific records, the second wave should happen between two months to two years [after the initial outbreak].''

State authorities should not lower their guard against the virus even though the rate of spread of the disease has stabilised in many countries.

''The government should make sure that we have enough anti-viral drugs. The virus is resistant to amantadine and rimantadine, but not to oseltamivir and zanamivir,'' he said.

Thailand has around 4 million tablets of oseltamivir. The Public Health Ministry plans to increase stocks of zanamivir, as an alternative treatment.

Although the source of outbreak is not clear, some reports have said the (A) H1N1 virus could have leaked from a laboratory during the process of developing new vaccines.

Jessada Denduangboribant, a lecturer at Chulalongkorn University's faculty of science, said that the virus' structure is astonishing.

''We found that its genetic code changes very quickly, which is unusual. There are eight segments of the viral genome, which is a kind of rearrangement of viruses from pigs, birds and humans.

''Normally, there should be some change in some segments. But in this case all of them have changed, which is very strange,'' he said.

The number of official cases of Thais infected with the (A) H1N1 virus still remains at two. Laboratory tests proved that a boy in Phitsanulok province, who was suspected of having the illness, was not infected with the disease.

The boy had returned from Mexico showing signs of infection but he has since made a full recovery, said Paichit Varachit, deputy permanent secretary for public health. Another suspected case, a 68-year-old man who returned from the US and is being treated at a hospital in Ayutthaya, was also cleared by tests. Fifteen people with flu-like symptoms are now being kept under medical observation in Thailand.