The Philippine government on Monday urged its nationals to cancel unnecessary travel to Mexico and other countries where there is an outbreak of swine flu virus.

All Filipinos traveling to Mexico, the country hit hardest by the virus, are also advised "to avoid large crowds, avoid shaking hands, kissing people as a greeting, and avoid using the subway," said the Philippine Department of Foreign Affairs.

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 103 people out of over 1,000 suspected cases in Mexico.

The Philippine government also suggested those with health concerns should stay at home or call their physicians to avoid possible exposure to the virus.

"The DOH (Department of Health) will distribute a health alert notice to all arriving travelers from the US and Mexico. Travelers will also be required to fill out a health declaration at all ports of entry in the Philippines to screen from potential exposure from the virus," said the Department of Foreign Affairs.

Esteban Conejos, Undersecretary of the Department of Foreign Affairs, said the government has not yet received any report from its embassies of a Filipino affected by the virus.

Conejos added that the government is not issuing a travel ban, but only asking Filipinos to reconsider going to the affected countries.

In case of infection, Conejos said Filipinos should immediately report to local health authorities in their respective host countries.

"That's immediate. While doing that they should also report to the embassy so that we can coordinate with the local health authorities in the area," he said.

Data from the Department of Foreign Affairs showed that there are 309 Filipinos in Mexico, 21 of whom are permanent residents.