Latin American countries announced preventive measures against swine flu, whose outbreak in Mexico has killed at least 20 people.

Mexican President Felipe Calderon Sunday called on all Mexicans to maintain calm amid the spreading of the epidemic.

The president asked them to go to medical centers rather than stay at home for self-medicating when related symptoms appear.

He also said contact with potential virus carriers should be avoided.

The World Bank said it would provide Mexico with more than US$200 million in loans to help the country in its fight against the outbreak.

The Mexican Education Ministry has ordered to close all educational institutions from nurseries in the affected areas until May 6.

The Argentine government has also issued an epidemic alert for airport and airlines staff.

The Argentine Health Ministry requested all airlines flying from Mexico to Argentina to report any case of passengers with flu symptoms. The government also asked all people with symptoms, who have been in the outbreak area, to seek medical assistance.

The Brazilian government announced measures such as passenger and luggage controls at airports to impede the virus.

Crew from airplanes coming from Mexico and the United States must report any case of people with flu symptoms.

In Venezuela, Health and Social Protection Minister Jesus Mantilla announced on Sunday the establishment of a National Committee of Preparation and Answer against Flu in an effort to deal with the contagious disease.

Mantilla said that the mechanism of sanitary control at airports will be reinforced.

He also suggested that Venezuelans should cancel tours to Mexico and the United States and to avoid visiting live-stock markets.

In Bolivia, the government said on Sunday that it would start checking all passengers coming from the United States and Mexico from Monday as a preventive measure.

It said that main check points would be installed at airports to identify people with flu-like symptoms.

In Costa Rica, Health Minister Maria Luis Avila told Xinhua on Sunday that the government had taken preventive measures, while in the last few hours three cases with suspicious symptoms were tested negative.

Also the country's Agriculture and Live Stock Ministry has been closely observing pig spices, and the transportation authorities have reinforced their attention at airports.

Meanwhile, the Chilean government activated on Saturday the National Commission of Answer to Outbreaks and Sanitary Emergencies.

Chile also set checkpoints at airports to exam passengers coming from Mexico and the United States, and any person with breathing disease symptoms will be taken to a specialized hospital for medical evaluation.

The Ecuadorian government announced on Sunday that it had boosted the sanitary vigilance and set check points at airports.

The Ecuadorian health minister Sunday rejected reports on any swine flu outbreak in the country.

He announced that the government had taken measures such as establishing check points at airports to prevent the epidemic.

Meanwhile in Guatemala, a country bordering southern Mexico, the authorities have issued yellow (preventive) alert and installed checkpoints at all ground and aerial entrances to the country to check all the people coming from Mexico and the United States.

In Honduras, the Health Ministry decreed on Sunday a "state of alert" and "permanent vigilance" in all the border points.

The Nicaraguan government also announced on Sunday extreme vigilance measures at border points and international airports.

The country's Health Minister Guillermo Gonzalez said that all the people with symptoms would be checked carefully.

He also said that a commission under the government would meet on Monday to analyze the situation and define if it was necessary to enhance the measure.

Meanwhile, the Peruvian authorities have announced such preventive measures as sending doctors to airports.

The Panamanian health minister also launched a sanitary alert due to the outbreak. The alert was designed for ports, airports and ground borders, according to a statement of the ministry.

The Panamanian authorities also said that they had upgraded the epidemic alert to detect suspicious cases.

In Uruguay, General Director of Health Jorge Basso was quoted as saying by local press on Sunday that "we are going to promote the vaccination against the flu and we will set check points" as measures to impede the virus.

Swine flue is a respiratory disease of pigs caused by type A influenza viruses. Outbreaks of swine flu happen regularly in pigs. People do not normally get swine flu, but human infections do happen.

Most commonly, human cases of swine flu happen in people who are around pigs and it is possible for swine flu viruses to spread from person to person also.

The new strain found in Mexico and the United States is a mixture of swine, human and avian flu viruses.