Swine Flu Not Present In U.S. Pigs; Veterinary Precautions Still Encouraged

Although the number of U.S. human cases of swine influenza A (H1N1) virus infection has climbed to 40, according to the Centers for Disease Control and Prevention’s latest figures, it still has not been detected in any U.S. pigs.

“At this point, it appears to be human-to-human transmission only,” said Ron DeHaven, DVM, chief executive officer of the American Veterinary Medical Assn. “We’ve been in contact with the American Association of Swine Veterinarians and there have been no reports of outbreaks among animals, although their members are certainly aware of what’s happening and are stepping up surveillance for the virus with federal and state animal health officials.”

For instance, the AASV on April 26 released information specifically geared toward veterinarians. Among  its key points:

  • The virus is currently transmitting person to person and does not involve pigs for transmission.
  • The virus is not known to be in U.S. pigs. 
  • The swine influenza virus is a zoonotic disease and appropriate precautions (i.e. hand-washing, mask and gloves during necropsies and personal equipment such as N95 respirators and goggles) should be implemented to minimize the risk of infection and disease transmission.
  • Increased awareness of suspicious cases involving pigs exhibiting influenza-like signs and particularly those pigs which have been previously vaccinated against SIV.
  • Submit diagnostic samples (lung tissues and nasal swabs) from acutely ill febrile pigs to the veterinary diagnostic lab if influenza is suspected.
  • Work with producers to increase their awareness and ensure appropriate biosecurity safeguards are in place to prevent the introduction of this virus into the U.S. swine herd.
  • Pork is safe to eat.

Bill Epperson, DVM, Dipl. ACVPM (epidemiology), head of pathobiology and population medicine with Mississippi State University’s College of Veterinary Medicine, said this new strain of the classic H1N1 virus is misnamed when referred to as swine flu.

“It’s only affecting humans, but the genome has human, swine and avian parts,” Dr. Epperson said. “Preliminary investigations revealed that none of the infected people had contact with hogs.”

Sandy Amass, DVM, Ph.D., Dipl. ABVP, professor of Food Animal Production Medicine at Purdue University, agrees.

“Flu viruses are named after the first animal they were found in,” she said. “This particular strain just happened to be discovered in pigs in 1930, and this is the only reason it’s called the swine flu. We don’t even know if the virus found in humans will infect pigs.”

Still, Dr. Amass urges pork producers to take precautionary measures:

  • Do not permit people, including employees that have the flu or flulike symptoms, in or around barns.
  • Do not allow any visitors to the farm, especially international visitors who have had contact with other livestock.
  • If pigs show flu symptoms—coughing, runny nose, fever and a reduction in feed intake—have them tested.

“It’s important to make sure your biosecurity procedures are being followed,” Amass said.



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