CDC says bird flu response is 'robust' as cattle infections spread, human risk stays low

Bird flu has jumped to cattle herds across the American heartland, and it has now sickened a second person in the United States. The virus, known as H5N1, first appeared in dairy cows in Texas in March, and by early April the infection had spread to eleven herds across four states—seven in Texas, two in Kansas, one in Michigan, and one in New Mexico, with another suspected case in Idaho still under investigation. A person in Texas who had contact with infected dairy cattle developed the illness, though their only symptom was red eyes, an unusual presentation for a virus that typically causes cough, fever, or difficulty breathing.

The Centers for Disease Control and Prevention moved quickly to characterize the threat. Dr. Nirav Shah, the agency's principal deputy director, stated plainly that while the overall risk to the general public remains low, the CDC is treating the situation with utmost seriousness. There has been no sustained human-to-human transmission in the United States, though sporadic cases of person-to-person spread have occurred elsewhere in the world. When humans do catch this version of the virus, infection typically stops with them or spreads only to someone in close contact, like a spouse. The Texas patient received antiviral treatment and was isolated; their case was mild, though the CDC acknowledges that bird flu can cause severe illness and death.

About fifteen people have been tested in connection with this outbreak, and only one tested positive. The CDC has expanded testing protocols to include anyone with symptoms who may have been exposed, partly because the Texas case presented with atypical signs. Shah explained that the agency wants to cast a wider net rather than risk missing cases. The virus recovered from the sick person is genetically identical to the strain circulating in the infected cattle and in wild birds, with no mutations detected that would reduce the effectiveness of existing vaccines, the antiviral drug Tamiflu, or diagnostic tests.

How the cattle became infected remains under investigation. The leading theory is that they encountered wild migratory birds, though the USDA cannot rule out cow-to-cow transmission, particularly through infected milk. The virus appears in high concentrations in milk from sick animals, but poses no threat to consumers because virtually all milk sold in the United States is pasteurized, a process that inactivates viruses before products reach store shelves. The FDA has reinforced its longstanding warning against raw milk consumption, with Shah noting that the agency's position has shifted from caution to emphatic urgency.

The economic impact appears contained for now. Cows typically recover within seven to ten days and do not need to be culled, unlike poultry, which often must be killed en masse to prevent wider outbreaks. None of the infected cattle had died as of the report date. The milk lost from symptomatic animals has been minimal and should not affect the nation's food supply or milk prices, the USDA said. However, the poultry industry has suffered far more severely. In early April alone, Michigan reported cases in a commercial facility, and Cal-Maine Foods, the nation's largest egg producer, announced it would have to depopulate 1.6 million laying hens and 337,000 pullets at a Texas facility—a loss the state agriculture commissioner called absolutely devastating for the region.

Since the outbreak began in January 2022, more than eighty-two million poultry across forty-eight states have been affected, along with over nine thousand wild birds, though the true number is likely much higher. The virus has also appeared in a growing list of mammals: baby goats, ducks, geese, deer, foxes, raccoons, opossums, skunks, and pet cats. The jump to cattle represents a significant shift that has drawn the attention of public health experts. Dr. Thomas Inglesby of Johns Hopkins Center for Health Security emphasized that whenever the virus crosses into a new species or a new human case emerges, authorities must investigate thoroughly to ensure it is not the beginning of a larger pattern.

The CDC and USDA have activated coordinated monitoring efforts, working with local health departments, veterinarians, and farmers to track sick animals and encourage rapid reporting. Shah stressed that the name "highly pathogenic avian influenza" should not alarm the public—the "highly pathogenic" designation refers to the virus's severity in birds, not humans. For migratory birds, the virus is indeed serious, carrying very high mortality rates among chickens and turkeys. For people, the risk remains low, provided they avoid raw milk and practice basic hygiene when handling wild birds. The situation is being watched closely, but for now, the nation's food supply and public health remain stable.