Photo by: TRACEY SHELTON

Masked officials at the Phnom Penh International Airport inspect passengers using a thermal scanner.

THE Ministry of Health and the World Health Organisation reported three more confirmed cases of influenzu A(H1N1), or swine flu, in Cambodia on Thursday, raising the total number of cases to four. So far, all confirmed cases involve the same school group of about 40 Americans from Kansas who arrived in Cambodia on Friday.

All four people - three women and one man - are receiving treatment at Calmette Hospital, where they are being held in isolation, said Chheang Ra, the hospital's director. The patients are 16, 17, 18 and 20 years old.

Hun Sen announced the additional three cases of swine flu on Thursday morning at a graduation ceremony at the National Institute of Education.

"We have four cases now in Cambodia, but we should not be surprised at the situation,"he said. "I appeal to all citizens to be careful."

At a press conference held by  the Ministry of Health and the WHO, Michael O'Leary, the WHO's country representative for Cambodia, said, "It was only a matter of time before [swine flu] arrived in Cambodia."

Even though all proper precautions had been taken, he said, "It is difficult to stop completely."

Minister of Health Mam Bunheng said at the press conference that Cambodia had about 300,000 Tamiflu tablets.

But Nima Asgari, a WHO public health specialist, said that most patients would need only lots of liquids, rest and paracetamol.

O'Leary emphasised that there was no need to panic. The virus spreads easily, he said, because "no one in the world has resistance".

"This virus is acting very similarly to the influenza virus every year," he added. He advised people to take simple precautions against infection such as washing their hands with soap.

According to WHO's latest figures, there have been nearly 56,000 confirmed cases of H1N1 worldwide.