A Texas patient tested positive for the bird flu virus after exposure to dairy cattle believed to be carrying the disease — the first known instance of cattle-to-human transmission in the United States, said public health officials on Monday. The patient reported eye redness, consistent with conjunctivitis, as the only symptom and was recovering, said the Centers for Disease Control.
“This infection does not change the H5N1 bird flu human health risk assessment for the U.S. general public, which CDC considers to be low,” said the federal agency.
Two years ago, a Colorado correctional inmate tested positive for bird flu after culling an infected flock. The man, under age 40, reported fatigue and was given an antiviral drug. The inmate worked on a 58,000-bird poultry farm in western Colorado as part of a pre-release program.
The H5N1 strain of highly pathogenic avian influenza (HPAI) has circulated widely around the world for years. Since 2003, more than 23 countries have reported more than 880 human infections with the H5N1 bird flu virus to the World Health Organization. Illnesses have ranged from mild, such as the U.S. cases, to severe, such as pneumonia, and even death in other countries.
Authorities withheld the name, age, sex, residence, and occupation of the Texas patient. The CDC said the patient “had exposure to dairy cattle in Texas presumed to be infected” with HPAI. The Texas Department of State Health Services said the patient “became ill following contact with dairy cows presumed to be infected with avian influenza.”
“Avian influenza A (H5N1) viruses have only rarely been transmitted from person to person. As such, the risk to the general public is believed to be low; however, people with close contact with affected animals suspected of having avian influenza A(H5N1) have a higher risk of infection,” said the state health department.
The Texas case “has alarmed disease trackers monitoring for the worst-case scenario: human-to-human transmission of the pathogen, which has happened infrequently worldwide and typically among family members engaged in work with animals,” said the Washington Post.
In new interim recommendations, the CDC said people exposed to birds or other animals with confirmed or suspected HPAI virus infection should be monitored for any signs and symptoms of illness for 10 days after the last known exposure, including those who wore recommended personal protective equipment.
So far, the USDA has confirmed HPAI in seven herds in Texas, two in Kansas, one in Michigan, and one in New Mexico. “The presumptive positive test results for the Idaho herd are still pending analysis” by the National Veterinary Services Laboratories in Ames, Iowa, it said.
HPAI, a virulent disease, can wipe out a flock within days. As a matter of routine, animal health officials kill every bird in an infected flock and quarantine farms in an attempt to contain the virus. Authorities say HPAI is spread by wild birds. More than 82 million birds in 48 states have died of bird flu or were killed as part of infected flocks since outbreaks began in February 2022. There are 645,000 dairy cows in Texas, the third-largest milk-producing state.
Bird flu is far less of a menace for livestock than birds. In dairy cows, it was evidenced by decreased appetite and milk production, with recovery in 10 to 14 days. HPAI has been found in dairy cattle in Idaho, Kansas, Michigan, New Mexico, and Texas.