Missouri records first positive case of bird flu without known animal contact | US News

A person in Missouri who had no known contact with animals tested positive for H5 avian influenza, the state Department of Health and Senior Services said Friday.

It's the first time a patient in the U.S. outbreak has had no known contact with sick animals. And it's the first time someone has been hospitalized for bird flu — although it's not yet clear whether the flu was the reason for the hospitalization or if it was a coincidence.

The patient, who has underlying medical conditions, was hospitalized on August 22 and tested positive for influenza A. Doctors sent a sample to the Missouri State Health Laboratory, where it was determined to be the H5 subtype, also known as highly pathogenic avian influenza.

The US Center for Disease Control and Prevention (CDC) confirmed that it was H5 and said the sample would be further investigated.

In previous cases, authorities have tried to determine whether the human cases are due to the strain that has been circulating among wild birds and mammals in the U.S. since 2022, or whether it is more closely related to the variant found specifically in dairy cows. They will also likely investigate whether the pathogen has mutated, making it more transmissible or virulent among people.

In an exclusive interview with the Guardian in July, Nirav Shah, deputy director of the CDC, said there were several issues with this outbreak that officials were paying attention to.

“One of them is the increasing severity of the disease,” such as when a person is hospitalized or dies from bird flu, he said.

Cases in the United States so far have been mild but have affected farmworkers, who are generally healthy and strong. In the general population, especially among people with other health problems, bird flu could prove more dangerous. Worldwide, the fatality rate is about 50% of confirmed cases – although there are likely less severe cases that go undetected.

“The second issue is the nature of transmission,” Shah said. “Are we seeing human-to-human transmission?”

In the two decades since H5N1 was detected in humans, human-to-human transmission has been extremely rare, he said.

Another major concern about transmission is who gets sick.

“If we were to see signs and symptoms in individuals with no connection to a farm or chicken contact, that would be extremely concerning,” Shah said. “Even if no other route of transmission has been identified, that would be a sign that something else is happening.”

Authorities will likely continue to track the patient's possible infections and contacts with other people to determine how the virus spread.

Avian influenza is normally found in domestic and wild birds, but in recent years its range has expanded considerably and is now widespread in mammals, including dairy cows and other farm animals.

Two domestic cats in Colorado recently tested positive for the virus. House mice have also tested positive.

No bird flu has been detected in cows in Missouri, but it has been detected in poultry and wild birds.

According to Missouri's press release, the virus “can occasionally infect humans through close contact with infected animals or in contaminated environments.”

This is the 15th human case of bird flu in the United States since 2022—and the 14th this year. This is the first known human case of bird flu in Missouri.

The patient has recovered and has been released from the hospital, Missouri's statement said.