People who work with poultry and swine, especially people with intense exposures, are at risk of infection from these animals if the animals carry a strain that is also able to infect humans. Swine Influenza Virus (SIV) can mutate into a form that allows it to pass from human to human.

The 2009 swine flu outbreak is the spread of a new strain of H1N1 influenza virus that was first detected by public health agencies in March 2009. Local outbreaks of influenza-like illness were detected in three areas of Mexico, but the presence of this new strain was not clinically discovered until a month later in the American states of Texas and California, whereupon its presence was swiftly confirmed in various Mexican states and Mexico City; within days isolated cases elsewhere in the Northern Hemisphere were also identified. By April 27, the new strain was confirmed in Canada, Spain, and the United Kingdom and suspected in many other nations, including New Zealand, with over 2,400 candidate cases, prompting the WHO to raise their pandemic alert level to 4.

Swine Flu Virus hasn’t reached the Philippine shores yet and that President Gloria Macapagal-Arroyo gave the directive to agricultural authorities after the World Health Organization declared the swine flu outbreak in parts of Mexico and the United States as a public health emergency.

Department of Agriculture has put the imports of pork products under strict surveillance while the Department of Health has been on the lookout for arriving flight passengers with flu-like symptoms.

Swine influenza can be transmitted through the air or through direct contact.