Expert warns of threat from deadly bird flu

A flu expert has warned that the deadly H5N1 bird flu virus strain could re-emerge in the country if stringent measures to prevent the spread of the disease are not taken.

The warning was issued yesterday at a health conference entitled ''The Emerging and Re-emerging Diseases: Situation, Lessons and Management'' held by Mahidol University.

Tawee Chotpitayasunond of the Queen Sirikit National Institute of Child Health told participants at the conference that the World Health Organisation (WHO) had reported 36 bird flu cases in humans over the past four months in four countries _ Cambodia, Bangladesh, Indonesia and Egypt.

Of the total, 16 had died and five of them were Cambodian nationals.

According to the WHO report, two of the five who died in February were a 21-year-old woman and her 11-month-old son. They had been sent for medical treatment at a hospital in Cambodia's Banteay Meanchey province, opposite Thailand's Aranyaprathet district of Sa Kaeo province. An investigation found the mother had contracted the virus from an H5N1-infected chicken she had killed and eaten.

When the deaths came to light, Thai health and livestock authorities immediately stepped up measures to prevent the spread of the disease in humans and poultry and to control the trade of eggs and poultry along the Thai-Cambodian border.

The reported number of bird flu cases in humans in the four-month period is higher than the 40 cases worldwide last year. Therefore, the prevalence of bird flu was likely to remain at least as severe as in the previous outbreak when it was at 60-70%, Dr Tawee said.

''If [Thailand] doesn't take stringent measures to prevent the flu spreading, particularly in areas where previous outbreaks have taken place, the virus may return to harm [Thai] people after years of having disappeared,'' he said.

He added the situation could turn into something similar to what was happening in Cambodia and Indonesia where the number of people who have died from bird flu has been rising continuously since the start of this year.

There have been no bird flu cases in humans in Thailand since July 2006 after previous outbreaks between 2004 and 2006. During that time, 27 infections were reported and 17 people died.

In a related matter, WHO Southeast Asia regional director Samlee Plianbangchang also warned there was another strain of the H1N1 influenza virus active in the region.

Dr Samlee said the deadly flu virus might re-emerge in Thailand and other developing countries at any time if these countries lacked effective surveillance.

Yong Puworawan, head of Chulalongkorn University's Centre of Excellence in Clinical Virology, said there were now signs that the H1N1 virus had become resistant to the anti-viral drug oseltamivir.

Following monitoring of the three waves of H1N1 flu outbreaks during 2009 and 2010, the drug resistance rate had shown signs of increasing.

Dr Yong said that in the first wave there were no drug-resistant cases, whereas the drug resistance rate of the H1N1 flu virus during the second and third waves was at 0.2% and 0.8% of the 1,200 cases of the H1N1 virus, respectively, he said.

The virologist, however, remained confident that the medicine was still effective in treating influenza because H1N1 had become a seasonal flu and about 40-50% of the Thai population had already been vaccinated.