H5N1 Bird Flu Detected in US Pig: A Public Health Concern

H5N1 Bird Flu Detected in US Pig: A Public Health Concern In a notable update, the U.S. Department of Agriculture (USDA) announced on Wednesday the first confirmed case of H5N1 avian influenza found in a pig in the United States. The infected pig belonged to a backyard farm that housed both poultry and livestock but exhibited no signs of illness. It was tested as a precaution alongside four other pigs, resulting in one positive case, with two negative results and two still awaiting results.

The USDA indicated that the farm operated non-commercially and was not part of the commercial food supply chain, assuring that this incident does not affect the safety of the nation’s pork supply. The farm has been quarantined to prevent further spread of the virus.

Experts express concern over pigs, which are known to be “mixing vessels” for flu viruses, as they can carry both human and avian influenza strains, posing new risks if the virus mutates to transmit among humans. The USDA has increased surveillance efforts on the farm under quarantine. Dr. Marc Siegel, a clinical professor of medicine at NYU Langone Health, highlighted that various flu strains can coexist in pigs and exchange genetic material, leading to new strains that could raise concerns, especially following the mild 2009 H1N1 pandemic associated with swine flu.

As reported by Scientific American, flu viruses consist of eight RNA segments that can be exchanged when multiple viruses infect the same cell, leading to 256 possible combinations that may enhance transmissibility. With a rise in avian flu cases among both animals and humans, worries about a potential outbreak are growing. With flu season approaching, it is crucial to vaccinate livestock to reduce transmission and prevent human infections. Symptoms of bird flu include high fever, chills, body aches, cough, and respiratory issues, along with gastrointestinal symptoms such as diarrhea and stomach pain. Early symptoms typically manifest 3-5 days after exposure.

H5N1 Bird Flu Detected in US Pig: A Public Health Concern The U.S. Department of Agriculture (USDA) confirmed on Wednesday that H5N1 bird flu was detected in a pig on a backyard farm in Oregon, marking the first case of the virus in swine in the country. Pigs are particularly concerning for the transmission of bird flu because they can be co-infected with both bird and human viruses, potentially leading to the creation of a new, more dangerous strain that could more easily infect humans. The USDA reassured that the Oregon case poses no risk to the national pork supply and that the public’s risk from bird flu remains low.

Richard Webby, a virologist at St. Jude Children’s Research Hospital studying animal and bird flu for the World Health Organization, noted that pigs were the source of the H1N1 flu pandemic in 2009-2010 and have been implicated in other outbreaks. He stated that the discovery of the virus on a small farm is less concerning than if it had been found on a commercial pig farm. “While it doesn’t significantly increase the risk, the situation could change if the virus starts transmitting among pigs,” he said.

The farm has been placed under quarantine, with other animals, including sheep and goats, under surveillance. The USDA reported that pigs and poultry on the farm were culled to limit the spread of the virus, and tests are still pending for two pigs. The H5N1 case in the swine is believed to have originated from wild birds rather than a poultry or dairy farm. Wild bird migrations have been responsible for spreading bird flu to livestock. As a result, the USDA announced a nationwide expansion of bird flu surveillance to include bulk milk testing, as mentioned by Agriculture Secretary Tom Vilsack in an interview with Reuters.

H5N1 Bird Flu Detected in US Pig: A Public Health Concern “Although this is a different variant of the virus linked to wild birds, it is essential to monitor its presence in dairy and bovine populations,” Vilsack said. The pigs from the Oregon farm were not intended for commercial food production, but the discovery did impact lean hog futures prices at the Chicago Mercantile Exchange.

The USDA indicated that pigs and poultry on the farm shared water, housing, and equipment, which have previously been pathways for virus transmission in other states. The detection serves as a warning to pig farmers to be vigilant for potential further infections, according to Marie Culhane, a professor of veterinary population medicine at the University of Minnesota who studies flu viruses in swine. “Farmers should enhance their preparedness in case of further outbreaks in other herds,” Culhane emphasized, noting that pigs are particularly adept at acquiring influenza viruses.

So far this year, 36 individuals have tested positive for bird flu, primarily among farm workers who had direct contact with infected animals. Since 2022, the virus has led to the loss of over 100 million poultry birds in what has been described as the worst bird flu outbreak in the nation’s history.

H5N1 Bird Flu Detected in US Pig: A Public Health Concern H5N1 bird flu has been detected in a pig on a backyard farm in Oregon, marking the first confirmed case of the virus in swine in the United States, as reported by the U.S. Department of Agriculture (USDA). Pigs are particularly concerning in the context of bird flu because they can be co-infected with both avian and human viruses, leading to the potential creation of a new, more dangerous virus that could spread more easily among humans. The USDA and Oregon state veterinary officials are investigating this incident, which involves a farm with a mix of poultry and livestock, including pigs.

The Oregon Department of Agriculture noted that the poultry on the farm represented the first detection of H5N1 in Crook County. On October 29, the USDA’s National Veterinary Services Laboratories confirmed that one of the five pigs on the farm tested positive for H5N1. Although the infected pig showed no symptoms, all five swine were tested due to the presence of the virus in other animals on the farm. The USDA reported that all five pigs were euthanized for further testing, with two testing negative and results still pending for the remaining two.

The agency highlighted that livestock and poultry on the farm shared water sources, housing, and equipment, which can facilitate the transmission of the virus between species, as seen in other states. The farm has been quarantined; however, since it is not a commercial operation, the USDA assured that there are no concerns regarding the safety of the nation’s pork supply.

Experts are worried about the possibility of H5N1 spreading to pigs, as they are considered “mixing vessels” for flu viruses due to their ability to carry the same types of receptors on their lung cells as humans and birds. The 2009 swine flu pandemic is believed to have originated from a virus that mutated in pigs in Mexico before infecting humans.

H5N1 Bird Flu Detected in US Pig: A Public Health Concern Additionally, a second person in Missouri, who had not been exposed to poultry or dairy cows, has tested positive for bird flu. This individual shared a home with another patient who was hospitalized for bird flu in August. However, antibody tests on healthcare workers who cared for the patient indicated that they were not infected with H5N1, according to the U.S. Centers for Disease Control and Prevention (CDC). The CDC confirmed that human-to-human transmission of H5N1 has not been observed in the U.S., and the immediate risk to the general public remains low. Nonetheless, individuals with exposure to infected animals are at a higher risk of contracting the virus.

California has reported 16 human cases of bird flu, while Washington State has identified two infected poultry workers and five others presumed positive. In total, the CDC reports 39 bird flu infections in the U.S. this year. Experts stress that while this case is currently isolated, it raises concerns because pigs can mix avian and human influenza strains. If H5N1 were to begin circulating among pigs, the greatest risk lies in the potential recombination of its genetic material with other circulating influenza strains, which could lead to a more transmissible virus for humans, similar to how the 2009 pandemic began.

The incubation period for H5N1 ranges from 2 to 5 days on average, with a possible maximum of 17 days. Symptoms in humans can include fever, malaise, cough, sore throat, and muscle aches, with severe illness potentially resulting from pneumonia complications.