New suspected cases of bird flu and increasing frequency of suspected outbreaks Wednesday were suggesting a nationwide pandemic of the animal disease ahead of the Lunar New Year holidays when tens of thousands of people travel southward to visit their hometowns.

Four new suspected cases of avian influenza (AI) have been reported since Tuesday, bringing the total number of confirmed and suspected cases to 56, according to the Ministry of Agriculture, Food and Rural Affairs.

A virulent H5N8 strain of AI has been confirmed in 27 cases so far after the country reported its first outbreak on Jan. 16 at a duck farm in Gochang, North Jeolla Province.

The animal disease is believed to have since spread to five other provinces including Gyeonggi Province which surrounds the capital Seoul. Only Gangwon and North Gyeongsang provinces, both forming the country's eastern coast, along with the southern resort island of Jeju currently remain free of any suspected AI case.

Ministry officials noted an increasing frequency of suspected outbreaks, but claimed a growth in the number of suspected or confirmed cases did not necessarily mean the spread of the virus.

"We do not think it is a spread of the disease from AI infected farms," Kwon Jae-han, head of the ministry's livestock policy bureau, said at a press briefing.

He said the recent outbreaks may have been caused by AI virus planted or spread before the country's quarantine efforts began.

The AI virus is said to have an incubation period of up to 21 days.

The government has singled out migratory birds as the original source of the latest AI outbreaks after the H5N8 strain was confirmed in a group of wild ducks found dead at a reservoir in North Jeolla Province.

"Sporadic outbreaks are possible at any time, and under current conditions, it appears the AI virus may be present everywhere," Kwon said.

Over 2 million animals, mostly ducks and chickens, have been or are set to be slaughtered since the virus outbreak earlier this month. (Yonhap)