Seventy-one people in the United States have been infected with avian influenza A(H5) viruses since the current animal outbreak began spilling into humans in early 2024, according to the Centers for Disease Control and Prevention.
Two patients have died.
The first fatality was a Louisiana resident infected with H5N1 after exposure to sick and dead birds in a backyard flock. The second was a Washington state resident infected with H5N5, a subtype that had never previously been confirmed in a human anywhere in the world.
Despite those deaths, health agencies continue to assess the risk to the general public as low. No sustained or known person-to-person spread has been identified among the 71 American cases, and most infections occurred after direct exposure to infected dairy cattle, poultry, backyard birds or contaminated animal environments.
The Count Covers A(H5), Not Only H5N1
The phrase “71 H5N1 cases” is not completely precise.
CDC’s national total covers human infections with avian influenza A(H5) viruses. Most were associated with H5N1 circulating among American dairy cattle and birds, but the 71st case was confirmed as H5N5.
That patient lived in Washington state, kept backyard poultry and domestic birds, developed symptoms in October 2025 and was hospitalized with severe illness in November. The patient later died on November 21. Genetic sequencing confirmed the first known human infection with an H5N5 virus.
Contact tracing did not find additional infections among people who had been close to the patient, and investigators found no evidence that the virus spread from that person to anyone else.
The First Death Occurred in Louisiana
The first American death associated with the current H5 outbreak was reported on January 6, 2025.
The Louisiana patient was older than 65, had underlying medical conditions and had been exposed to sick and dead birds in a backyard flock. It was also the first severe US H5N1 case linked to backyard birds.
CDC said the death was tragic but not unexpected because avian influenza can cause severe respiratory illness and death in people.
No additional cases were found among the Louisiana patient’s contacts, and the incident did not change the agency’s assessment that the immediate risk to the broader public remained low.
Most American Cases Were Mild
Most recent US infections have occurred among people working directly with infected animals.
Earlier CDC data showed that 41 cases were associated with exposure to infected dairy cattle, 24 involved commercial poultry workers, two were linked to backyard flocks and three had no confirmed exposure source. The Washington H5N5 infection later raised the national total from 70 to 71.
Eye redness or conjunctivitis was the predominant symptom among many infected dairy and poultry workers. Other possible symptoms include fever, cough, sore throat, runny nose, fatigue, headaches and muscle aches.
The generally mild pattern among workers should not be interpreted as proof that H5 infections are harmless. Avian influenza can also cause pneumonia, respiratory failure, brain inflammation and death, particularly when infection reaches the lower respiratory tract.
No Known Person-to-Person Spread Has Occurred
The most important question is not simply how many people have been infected by animals. It is whether the virus has gained the ability to spread efficiently between humans.
US and international investigations have not identified person-to-person transmission associated with the 71 American cases.
That finding is why CDC and the World Health Organization continue to describe the general public risk as low.
An avian virus that infects an exposed worker occasionally is a serious occupational and animal-health problem. A virus that spreads consistently through coughing, breathing and ordinary social contact would present a much larger pandemic threat.
There is currently no evidence that the H5 viruses circulating in US animals have reached that stage.
The Virus Has Spread Widely Among Animals
H5 viruses remain widespread in wild birds and continue causing outbreaks in poultry, dairy cattle and other mammals.
A joint assessment from the World Health Organization, the Food and Agriculture Organization and the World Organisation for Animal Health reported that 1,088 US dairy herds across 19 states had tested positive for H5N1 by March 1, 2026.
The same assessment documented thousands of detections in American wild birds and hundreds of poultry outbreaks. H5 viruses have also been found in terrestrial and marine mammals, demonstrating repeated movement beyond their traditional bird hosts.
Every new animal infection gives the virus another opportunity to reproduce and change. Most mutations do not make it more dangerous to humans, but continued surveillance is necessary to detect changes associated with mammalian adaptation, antiviral resistance or increased transmission.
Dairy Workers and Poultry Workers Face Higher Risk
For most Americans, ordinary daily life does not involve close contact with infected animals.
Farm workers, veterinarians, poultry cullers, wildlife personnel and people handling sick backyard birds face a different level of exposure. WHO assesses the risk for people with occupational exposure as low to moderate, compared with low risk for the wider population.
The virus may be present in respiratory secretions, saliva, feces, milk and contaminated materials around infected animals.
Workers can be exposed when milk or other material splashes into their eyes, when they inhale droplets or dust, or when they touch contaminated surfaces and then touch their face.
CDC recommends protective clothing, gloves, eye protection and appropriate respiratory protection for people working with infected or potentially infected animals. Exposed workers are generally monitored for symptoms for 10 days after their last contact.
More Than 33,000 Exposed People Have Been Monitored
Between February 2022 and June 27, 2026, federal, state and local health departments monitored at least 33,100 people who had been exposed to infected birds, dairy cattle or other animals.
At least 1,340 were tested for a novel influenza A infection.
CDC’s national surveillance systems showed no indicators of unusual A(H5) influenza activity among the broader population through late June 2026.
These surveillance results support the conclusion that infections remain sporadic and closely associated with animal exposure rather than undetected widespread transmission between people.
Pasteurized Milk Remains Considered Safe
The dairy-cattle outbreak has created concern about whether milk could transmit the virus.
USDA and the Food and Drug Administration say pasteurization effectively inactivates H5N1 and that the commercial pasteurized milk supply remains safe. Milk from visibly affected animals is required to be diverted from the commercial supply.
Raw milk does not receive the same heat treatment and may contain infectious organisms, including influenza viruses and bacteria.
People should avoid consuming raw milk or feeding raw dairy and meat products to pets. A CDC investigation found evidence of H5N1 transmission from infected domestic cats to a veterinary worker after cats became sick from consuming raw animal products.
Cooking poultry and eggs to safe internal temperatures also destroys influenza viruses and other foodborne pathogens.
Backyard Flocks Require Caution
The two fatal US infections were both associated with people who kept or encountered birds outside a large commercial workplace.
Backyard poultry can become infected after contact with wild birds, contaminated water, droppings or shared outdoor environments.
Owners should not handle sick or dead birds with bare hands. Children and pets should be kept away, and unusual illness or deaths should be reported to animal-health authorities.
Anyone who develops eye redness, fever, cough or respiratory symptoms within 10 days of contact with a sick or dead bird should tell a healthcare provider about the exposure. Standard seasonal-flu testing may not automatically identify an avian virus, so the exposure history is important.
Seasonal Flu Vaccines Do Not Directly Prevent H5 Infection
The ordinary annual influenza vaccine is designed against seasonal human flu strains. It is not a dedicated H5N1 or H5N5 vaccine.
Receiving a seasonal vaccine is still recommended because it reduces the chance that a person will be infected with seasonal influenza and an avian virus at the same time.
Coinfection is a concern because influenza viruses can exchange genetic material when they infect the same host. Reducing seasonal influenza infections among exposed workers may therefore provide an additional layer of protection.
The United States also maintains candidate vaccines and preparedness programs for avian influenza, but a mass public H5 vaccination campaign has not been recommended under the current risk assessment.
The Global Fatality Percentage Can Be Misleading
Historically, nearly half of the confirmed H5N1 cases reported worldwide since 1997 have resulted in death.
That percentage should not be applied directly to the current US outbreak.
Older global cases often involved people sick enough to be hospitalized and tested, while mild or symptom-free infections were more likely to go undetected. The viruses circulating in different countries and periods are also genetically distinct.
Recent American cases among dairy and poultry workers have generally been much milder than many historical infections reported in Asia and other regions.
The two US deaths nevertheless demonstrate that severe outcomes remain possible, particularly in older people, those with underlying conditions and patients exposed to infected backyard birds.
What Would Cause the Risk Assessment to Change?
Public-health concern would rise sharply if investigators detected infections among people with no animal exposure that could be connected into transmission chains.
Clusters within households, workplaces or healthcare facilities would receive particular attention.
Scientists would also watch for viral changes that improve the virus’s ability to attach to human airway cells, reproduce efficiently in people or spread through respiratory droplets.
A sustained increase in unexplained influenza cases, hospitalizations or wastewater detections could also signal a change.
CDC currently says its surveillance systems show no unusual influenza activity linked to A(H5), but the agency continues monitoring national and local data.
What the General Public Should Do
Most people do not need to change their normal activities because of the current human case count.
The main precaution is to avoid unprotected contact with sick or dead birds, poultry, cattle and other animals. People should also avoid touching contaminated droppings, litter, raw milk or equipment without appropriate protection.
Dead wild birds should be reported according to local wildlife or animal-health guidance rather than picked up by hand.
Only pasteurized dairy products should be consumed, and meat and eggs should be cooked thoroughly.
Someone who becomes ill after animal exposure should contact a healthcare provider promptly and explain exactly what contact occurred. Antiviral treatment is most useful when started early.
The Main Takeaway
The United States has reported 71 human infections with avian influenza A(H5) viruses since February 2024.
Most were mild and occurred among workers exposed to infected dairy cattle or poultry. Two people died: a Louisiana resident with H5N1 and a Washington resident with the first known human H5N5 infection.
No known person-to-person transmission has been identified, and national surveillance has not found signs of unusual H5 influenza activity among the wider population. Health agencies therefore continue to assess the general public risk as low.
The outbreak remains important because the virus is circulating widely among birds, cattle and other mammals. Continued spillover increases opportunities for viral change and exposes farmers, veterinarians and backyard-flock owners to preventable infection.
For most Americans, bird flu is not currently an everyday transmission threat. For people handling infected animals, it remains a real occupational hazard that requires protective equipment, monitoring and rapid medical attention.
