“Influenza is strictly a disease of the respiratory system, and these viruses are not known to infect meat,” said Beth Young, University of Missouri Extension veterinarian and swine disease expert.

Young and other members of the University of Missouri Extension Commercial Agriculture Program swine focus team want to keep producers and the public up-to-date with accurate information. The main concern for producers is to keep their pigs protected from the virus from sources outside of the production site.

The National Pork Producers Council and the National Pork Board are urging all pork producers to use industry standards to reduce transmission of influenza viruses between pigs and people.

Joe Zulovich, structures engineer for Missouri's commercial agriculture program and a ventilation expert, says producers should immediately check their ventilation systems to be sure they are in working order. “If a producer was considering upgrading his system, now is probably the time to make that investment,” he adds. 

Maintaining appropriate ventilation in the barns will reduce pigs' exposure to viruses from other pigs and to human influenza viruses. It also will reduce exposure of workers to swine influenza viruses.

The virus identified in the current outbreak, misleadingly named “swine flu,” belongs to the Type A H1N1 virus subtype. H1N1 is unusual as it can cause disease in many species. Birds are especially susceptible as both victims and carriers.

Pork producers should maximize protection of herds by sealing or screening doorways, windows and airflow vents in swine housing units to prevent birds from entering. Unlike migrating waterfowl, small birds are not thought to be important in the overall ecology of influenza viruses, but they may carry the virus from waterfowl feces into barns on their bodies.

Pig feed should be stored in closed containers to prevent contamination with feces from waterfowl flying overhead. Producers should not use untreated surface water as either drinking water or for cleaning in swine facilities. It would be prudent to minimize waterfowl use of farm lagoons.

Vaccinating pigs for currently circulating swine influenza can reduce shedding of those viruses by infected animals, but there is no vaccine available for the current Type A H1N1 influenza virus strain. 

Pork production workers and their families should be vaccinated for human influenza virus on a yearly basis. Vaccination will provide some level of protection against infection with swine viruses of the same hemagglutinin subtype, points out Young. Employee vaccination also will reduce the amount of virus they'll shed if infected during human flu outbreaks, and thereby limit the potential of infecting pigs with human influenza viruses.

To further reduce that risk of infection, farm owners should provide sick-leave policies for employees that ensure that they do not work when they are suffering from acute respiratory infections. People typically shed influenza viruses for three to seven days.

Producers should enforce basic hygiene — thorough hand washing (20 seconds with soap and hot water) and industry-standard biosecurity practices. Producers should provide workers with boots that are worn only within the pig housing units. Workers should change clothes prior to leaving swine barns for office facilities, food breaks or their homes.

Hand-to-face contact should be minimized and hand-washing stations should be available throughout animal housing areas.

Public access to barns should be restricted.

Source: University of Missouri