There is no human case of swine flu in the Philippines and precautionary measures have been taken to prevent a domestic outbreak of the disease after human infections were officially reported in the United States and Mexico, health officials said on Monday.

"There is no report of swine flu among humans in Philippines," Philippine Health Secretary Francisco Duque said at a press conference in Manila, amid fear that the disease may have hit the northern province of Pangasinan.

Over the weekend, local media reported that swine flu has been detected in the province, saying that "the disease initially afflicted hogs raised in backyard farms."

Duque said that health authorities had not reported any recent case of swine flu among hogs in Pangasinan. Officials say the media reports are yet to be confirmed.

Duque said that the Department of Health (DOH) had taken a series of measures to keep the disease out of the Southeast Asian country.

"Following the World Health Organization alert among member states, the DOH has stepped up surveillance measures to prevent the entry of the virus," said the health chief.

The World Health Organization reported on its website that as of April 26, the Mexican government reported 18 laboratory- confirmed human cases of swine influenza A/H1N1 while the US government reported 20 laboratory-confirmed human cases. Meanwhile, the health agency said there had been no reported human cases of the virus in the Western Pacific Region.

Swine flu is a highly contagious acute respiratory disease of pigs, caused by one of several swine influenza A viruses. Outbreaks in pigs occur year round, with an increased incidence in the fall and winter in temperate zones. Swine flu viruses are most commonly of the H1N1 subtype, but other subtypes are also circulating in pigs (e.g., H1N2, H3N1, H3N2). H1N1 is the subtype that has killed more than 60 people out of about 1,000 suspected cases in Mexico.

In the Philippines, health officials have ordered a heightened alert at airports especially for passengers arriving from the United Stated and Mexico. Precautionary measures are also being taken in major ports which pork imports are usually passing through.

The health authorities have even advised Filipios not to hug and kiss in public to avoid possible spread of the disease.