An outbreak of a hybrid form of swine influenza has not affected the safety of pork, according to the Centers for Disease Control and Prevention (CDC), which has identified 20 people in the United States infected with the flu virus. More than 1,300 people in Mexico have been infected with the same flu type, which is a hybrid of avian, swine and human flu.

During an April 26 White House briefing, U.S. Department of Homeland Security Sec. Janet Napolitano said people cannot get swine flu from eating pork.

Preliminary investigations indicate that in all the cases there was no contact with swine. The influenza hybrid isolated from the cases is unique and not previously recognized in either pigs or people. According to the CDC, “This virus is different, very different from that found in pigs.” At this time there is no evidence that the hybrid influenza is present in pigs in the United States. The CDC’s investigation continues.

While the current cases are not strictly swine influenza, the National Pork Board is collaborating with the CDC and the United States Department of Agriculture (USDA) to provide information on swine flu. Information on influenza can be found in the fact sheet, “INFLUENZA: Pigs, People and Public Health” available at http://www.pork.org/PorkScience/Documents/PUBLICHEALTH%20influenza.pdf

Influenza virus in meat:

• The risk of illness from consuming pork is minimal. The CDC said Thursday that humans cannot contract this hybrid influenza from eating pork.
• In pigs, swine influenza is a respiratory disease. Few reports exist supporting theories of influenza entering the bloodstream or causing systemic infection in pigs. Therefore, it is reasonable to expect that swine influenza cannot be found in pork or pork products.
• If an animal with active swine influenza infection should arrive at a harvest facility, it would not pass the Food Safety Inspection Service (FSIS) ante-mortem inspection and would be condemned as an animal not fit for human consumption.
• FSIS has stated that even if surface contamination of a product should occur, common-sense food handling and preparation practices would minimize the risk of illness as normal cooking temperatures should inactivate the virus.

Background information on swine influenza in pigs:

• The clinical signs and/or symptoms of influenza in pigs are fever, lethargy, lack of appetite and coughing.
• As external temperatures drop in the fall and winter, influenza persists better in the environment. Extreme temperature changes and other stressors can affect the susceptibility of pigs to the virus.
• Influenza season in pigs typically runs from November through April, although influenza viruses can be isolated from pigs year round.

About interspecies transmission:

• It is possible for humans to transmit some influenza viruses to pigs. And it is possible, though not common, for pigs to transmit some influenza viruses to humans.
• Interspecies infections are most likely to occur when people are in extremely close proximity to pigs.
  • The current cases have been investigated, and it appears that they did not have contact with swine.

Reducing interspecies transmission of influenza viruses:

• It is in the best interest of both human public health and animal health that interspecies transmission of influenza viruses from people to pigs and pigs to people be minimized.

Pork producers should work with their herd veterinarian to reduce transmission of influenza viruses by:

• Giving influenza virus vaccination of pigs.
• Giving influenza virus vaccination of swine farm workers.
• Implementing worker sick-leave policies that encourage employees to remain away from work when they are suffering from acute respiratory infections. People typically shed influenza viruses for approximately 3-7 days, with the period of peak shedding correlated with the time of most severe clinical illness.
• Maintaining appropriate ventilation in the barns.
• Enforcing basic hygiene and biosecurity practices, including the use of personal protective gear.
• Preventing pig-to-bird contact. Bird-proof buildings and treat water if it supplied from an open body of water where birds and migratory fowl may be found. Separate pig and bird production to prevent any potential cross-contamination of the animals with influenza virus. Protect feed from feces of birds and migratory fowl.