Information for farmers
As swine producers, you are aware that swine influenza is common worldwide, including the United States, and commercial producers generally vaccinate for it. The strains that affect pigs are H1N1, H1N2, and H3N2,, and there are substrains within these. The strain that has been circulating in U.S. swine in recent years is H3N2, but the vaccine that is commonly used is “multivalent,” also protecting against other strains.  The strain now in the news as a human disease is an H1N1, but it is apparently a completely new substrain.  We have not seen it in swine anywhere in the world to date.

H1N1 as it is circulating in humans today contains genetic material from swine, bird and human strains of influenza.  Because is a completely new virus, your animals have no immunity to it, just as people have no immunity to it.  Swine producers have some of the best biosecurity practices in animal agriculture, but now you need to step up your vigilance even more to protect your herd from this new virus.

Clinical signs
This is a new virus, so we cannot be certain what the clinical signs would be, but we can talk about how influenza generally presents in hogs. The incubation period is usually short, 12-48 hours after exposure, and the onset is usually dramatic and rapid. Clinical signs:

• Fever that causes abortions in sows
• Severe, widespread coughing
• Pneumonia
• Loss of appetite
• Sudden prostration
• Heavy breathing
• Severe coughing
• Most look as if they are going to die, but survive without treatment unless the herd already has a respiratory disease problem.

If you or your employees see any sign of respiratory illness in pigs, contact a swine veterinarian immediately, especially if the onset or presentation of this illness is unusual. 

Biosecurity measures

• Enforce a strict sick leave policy for workers with symptoms such as fever, cough, body aches, and sometimes vomiting and diarrhea.  
• Keep these workers out of swine facilities for at least seven days, even if their symptoms are mild.
• Recommend that workers with these symptoms see a doctor.
• Encourage workers to report if members of their household have these symptoms, and to have those family members see a doctor.  Consider restricting the contact that such workers have with animals.
• Limit entry of people into your facility to workers and essential service personnel.
• Follow other generally accepted biosecurity practices, including:
• Workers should shower and change into farm-specific clothes and shoes before entering swine facilities.  If this is not possible, at least require the use of farm shoes and hand- and arm- washing before contact with pigs.  
• Frequent hand-washing should be the rule in barns and offices. 
• Provide basic personal protective equipment to the people working in barns -- face masks, or preferably respirators, eye protection and gloves.
• Vaccinate pigs against the influenza virus to reduce the levels of virus shed by infected animals.

Centers for Disease Control Guidelines for Workers on Swine Farms