A new outbreak appears to be spreading in the United States. Several animals have been found infected with H5N1 avian influenza, many of which have since died.
Which animals are infected with the H5N1 virus.
As the American Veterinary Association (AVMA) reports, dozens of domestic cats have tested positive for H5N1, the symptoms of which can be severe: poor appetite, inflamed eyes, difficulty breathing, lethargy, nasal discharge, fever or other “neurological signs.”
Many U.S. zoos have reported cases of infection of big cats (e.g., cougars, tigers, leopards and bobcats). Last December, the Wildlife World Zoo in Litchfield Park, Arizona, reported that a cheetah, mountain lion, swamphen, Indian goose, and a kookaburra all died from exposure to H5N1, or bird flu.
Seattle’s Woodland Park Zoo reported the death of a red-breasted goose that was found positive for highly pathogenic avian influenza. The zoo said it would take “additional health and safety precautions” to protect its birds, staff and guests.
Food as a vehicle for virus circulation
The virus has also been found in dairy cattle, pigs, and poultry, and this can be particularly dangerous because these animals often become the food of other animals, including those living in captivity, in zoos, and in our homes. Recent surveys, in fact, point precisely to food as a source of infection; we are talking about unpasteurized milk and raw or undercooked meat.
It turns out, therefore, to be important to keep pets away from wild birds, uncooked milk and meat.
The spillover
As is often the case, the genomes of viruses found in infected animals can undergo mutations so as to adapt for survival in other species. Again, the H1N5 virus changed to infect humans as well.
AVMA reports that since the outbreak began in cattle, avian influenza virus type A (H5) infection has been confirmed in 67 people in the United States. Twenty-three of these cases have involved poultry farm workers exposed to infected poultry in Washington (11 cases), Colorado (9 cases), and Iowa, Oregon, and Wisconsin (1 case each). Forty other cases involved dairy farm workers exposed to sick or infected cows: 36 in California, two in Michigan, one in Texas, and one in Colorado.
How will the virus evolve?
The Centers for Disease Control and Prevention (CDC) say the risk to public health remains low at this time. The U.S. Department of Agriculture (USDA) and the Food and Drug Administration (FDA) also continue to state that they have no concerns about the safety of the commercial supply of milk and other foods for human consumption because the products are pasteurized before entering the market and, therefore, rendered harmless.
In the meantime, however, the virus continues to circulate and the housing of animals, such as in zoos or on farms, remains a major risk factor. Keeping animals locked up that are not threatened in the wild is, not only a cruel act, but also a dangerous fact because it can promote the onset of potentially global pandemics.
