Can pets be affected by the swine flu?

Q: How can a pig virus infect people?

A: Most viruses have difficulty spreading between different species. Even fewer develop the ability to spread both between and within multiple species. For example, the previous avian influenza (H5N1) scare fizzled out because the virus had difficulty spreading between people even after it had developed the ability to jump from birds to humans.

The current “swine” flu outbreak is not technically a “pig virus.” The Centers for Disease Control and Prevention, has determined that the new influenza A (H1N1) strain contains genetic material from four different viruses. One is a swine influenza commonly found in North America. The others are a human influenza virus, a North American avian influenza virus, and another pig influenza more typically found in Europe and Asia. 

There are multiple types of influenza viruses and most are limited to one specific type of animal. However, under the right circumstances pigs are susceptible to carrying influenza viruses that normally live in birds and people. Epidemiologists have long been concerned that multiple viruses infecting the same pig could exchange genetic material to create a different virus. It is unclear if that is what happened with the new H1N1 influenza. The CDC, Pan American Health Organization, and World Health Organization continue to investigate the virus’ origin.

According to the CDC, the virus spreads mainly by person-to-person contact through coughing or sneezing. As I write this column, all of the infections reported in this country have come from exposure to infected people, not pigs. In addition, the U.S. Department of Agriculture (USDA) has not received any reports of pigs infected with the virus. To be consistent with the naming of other outbreaks of influenza in the human population, the World Organization for Animal Health recommends the virus be referred to as the “North American” flu instead of the “swine” flu.

Q: Can my pets be infected?

A: There is no evidence that dogs, cats, or “pocket pet” species can be infected with the new H1N1 strain of influenza virus. Although the virus contains some genetic material from an avian influenza virus, there is no evidence this strain can infect birds. Even so, you should contact your veterinarian any time your pet develops symptoms of a respiratory infection.

The USDA recommends that pot-bellied pig owners “should learn the warning signs of swine influenza. Signs of swine flu in pigs can include sudden onset of fever, depression, coughing (barking), discharge from the nose or eyes, sneezing, breathing difficulties, eye redness or inflammation, and going off feed. If your pig is showing any of these signs, call your veterinarian.” They also stress that there have been no reports of this virus in domestic pigs and there have been no cases of spread between people and pigs in this country. Still, “a network of Federal veterinarians, state animal health officials and private practitioners are regularly involved with monitoring U.S. swine for signs of significant disease.”

Q: There are feral pigs in my area. Can they spread the flu virus?

A: According to the American Veterinary Medical Association (AVMA), “since this virus hasn’t been found in pigs, feral pigs are not likely to catch or spread the disease. However, they can spread other diseases, and it is best to avoid contact with them—this goes for you and your animals. Feral pigs are best left to the proper authorities to handle, so contact your local animal control office if you need to report a feral pig problem.”

Q: Where can I get more information on the new flu virus?

A: Since this is an emerging virus, available information is changing rapidly. The CDC’s web page, cdc.gov/swineflu/, has the most up to date information. The AVMA is also regularly updating their web site at avma.org with specific information related to H1N1, pigs, and pets. The Virginia Department of Health has also posted information on the virus outbreak at vdh.virginia.gov.

Dr. Watts is a companion animal general practitioner and owner of Clevengers Corner Veterinary Care. He can be reached through ClevengersCorner.com or by calling 428-1000.