Gov. Gavin Newsom declared a state of emergency Wednesday as the H5N1 bird flu virus moved from the Central Valley to Southern California dairy herds, while federal officials confirmed the first U.S. case of severe illness in a hospitalized Louisiana patient — a concerning development as the virus continues to spread throughout the nation via migrating birds.
The declaration by Newsom will allow for a more streamlined approach among state and local agencies to tackle the virus, providing “flexibility around staffing, contracting, and other rules to support California’s evolving response,” according to a statement.
“Building on California’s testing and monitoring system — the largest in the nation — we are committed to further protecting public health, supporting our agriculture industry, and ensuring that Californians have access to accurate, up-to-date information,” Newsom said in the statement. “While the risk to the public remains low, we will continue to take all necessary steps to prevent the spread of this virus.”
According to the U.S. Department of Agriculture, 645 dairy herds in California have reportedly been infected with the H5N1 virus since August. Nationwide, the number is 865 and stretches back to March, when the virus was first detected in Texas herds.
There have also been a number of infections identified in pet cats in California, including three announced on Wednesday.
According to the CDC, 61 people have acquired the virus since March — the vast majority at dairies or commercial poultry operations. Most suffered from mild illness, including conjunctivitis, or pink eye, and upper respiratory irritation.
In California, 34 people have become infected with H5N1, with all but one contracting the virus from infected dairy. The outlier was a child in Alameda County; the source of that infection has not been determined. There was also a suspected case in a child from Marin County who drank raw milk known to be infected with the virus. The CDC was unable to confirm illness in that child.
The case in Louisiana is concerning to public health officials because of its severity. Federal officials would not provide details about the patient’s symptoms, deferring all inquiries to Louisiana’s Department of Public Health.
Emails and calls to that agency went unanswered.
According to CDC officials, the patient was reportedly in close contact with sick and dead birds from a backyard flock on the patient’s property. The virus was a version of the H5N1 bird flu that researchers have labeled D1.1 and is circulating in wild birds.
The strain circulating in dairy cows is known as B3.13.
It was the D1.1 version that was detected in a Canadian teenager hospitalized with severe illness in November. The source for that patient’s infection remains unknown.
According to Demetre Daskalakis, director of the CDC’s National Center for Immunization and Respiratory Diseases, Louisiana health officials and the CDC are investigating the patient’s contacts and performing further genetic analysis of the patient’s virus to determine what, if any, changes may have have occurred.
“These additional laboratory investigations help us to identify concerning changes in the virus, including changes that would signal an increased ability to infect humans, increased ability to be transmitted from person to person, or changes that would indicate that currently available diagnostics, antiviral treatments or candidate vaccine viruses may be less effective,” said Daskalakis in a news conference Wednesday morning.
He said analyses so far have not indicated changes in the virus that would make it “better adapted to infect or spread among humans.”
Analyses of the Canadian teen’s virus showed mutational changes that would make it easier for that version of H5N1 to infect people. However, it is unclear if those changes came prior to the infection — in the wild — or during the course of the child’s infection.
None of the child’s family members or contacts were infected, suggesting the changes occurred in the teenager during the infection and therefore the virus reached a dead end when it was unable to spread beyond the child.
These cases are akin to those recorded historically in Asia and the Middle East, where the H5N1 virus had resulted in a mortality rate of roughly 50%. Since the virus was first identified in 1997, there have been 948 cases reported worldwide leading to 464 deaths.
The cases associated with the B3.13 strain circulating in the nation’s dairy herds have so far resulted in only mild symptoms.
Still, research indicates that changes in at least one viral isolate taken from a dairy worker in Texas had acquired mutational changes that allowed for airborne transmission between mammals, and was 100% lethal in laboratory ferrets.
However, as in the case of the Canadian teen, it is believed that version was unique to the dairy worker and did not spread beyond.
Other research shows that only one mutational change is required for the B3.13 version to pass efficiently between people.
The D1.1 version of the virus “worries me a bit,” said Richard Webby, director of the World Health Organization’s Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds. “Not necessarily because I know it will evolve differently, but it does have a different combination of H5 and N1 which theoretically could help support a different set of mutations” than what researchers have seen in experiments with the B3.13 version.
Daskalakis said the CDC still considers the risk to the general population to be low, and the agency is working to expedite influenza and bird flu testing in clinical and public health laboratories “to help accelerate identification of such cases through its routine influenza surveillance.”
According to Newsom’s office, “California has already established the largest testing and monitoring system in the nation to respond to the outbreak.”
