A new outbreak of a deadly strain of bird flu has been detected in Thailand, prompting the government to declare a high alert throughout the country. In nearby Vietnam, the government confirms that at least six people have died from the same H5N1 virus and one-third of the country’s poultry has been infected in recent weeks.

Thai officials confirmed Thursday the year’s first outbreak of the H5N1 virus. Scientists found the lethal bird flu strain in 20 fighting cocks in the eastern province of Rayong and in 50 chickens in the central province of Phitsanulok.

Officials say both districts have been placed under a 21-day surveillance period and no poultry can be taken in or out of the area during this time. A high alert has been placed across the country and systems to monitor and prevent the spread of the disease are in place.

In Vietnam, at least six people who either ate infected chicken or had close contact with infected fowl, have died of the virus since last month, while one other person remains infected. The government says up to 10 more human cases are suspected.

The H5N1 strain emerged last year in Vietnam and Thailand, before spreading to several other Asian countries and decimating the region’s poultry business.

At least 26 people have died of bird flu in Vietnam and 12 have died in Thailand.

To date more than 100 million chickens have been culled throughout the region.

Peter Cordingley, the World Health Organization’s Western Pacific spokesman, says this stage of the outbreak is similar to last year’s. He describes the virus as dangerous and versatile and says it will continue to spread.

“We were saying for a large chunk of the second half of last year that this virus is embedded, it hasn’t gone away, and it doesn’t matter what some governments say about having it under control,” he said. “It was never under control. We expected it to return when the cooler weather kicked in.”

Health experts are concerned about the disease spreading in Vietnam ahead of the Tet New Year holiday in early February. Chicken is the traditional family meal during the festival.

The communist nation has banned the import of poultry from neighboring nations, but domestic sales are allowed, making it easier for the disease to spread.

While most of those who have died from bird flu are thought to have caught the disease from contact with fowl, a few cases of human-to-human infection have been reported.

The World Health Organization says there is no evidence yet that the virus has changed into one easily transmitted by human-to-human contact, but they fear that may change.

The WHO’s Peter Cordingley says it doesn’t take much genetically for the virus to change. If it merges with a human flu virus, it could produce a virulent strain capable of killing millions of people worldwide.

“With each time that the virus jumps to humans, and we’re looking at six cases in a matter of seven weeks in Vietnam, the chances of this change taking place grows,” he said, “then we’re looking at the potential of a flu pandemic caused by a virus that nobody has encountered before and against which there is no resistance.”

Other Asian nations, such as Hong Kong, are also on alert for the virus and are warning citizens to avoid contact with poultry while traveling.