First human case of H5 bird flu confirmed in Los Angeles County

A human case of H5 bird flu has been confirmed for the first time in Los Angeles County in California, according to health officials. The individual was exposed to infected livestock.

“The Los Angeles County Department of Public Health (LACDPH) has confirmed a human case of H5 bird flu in an adult who was exposed to livestock infected with H5 bird flu at a worksite,” said a statement released on Monday. “This is the first human case of H5 bird flu detected in LA County.”

The patient is currently recovering at home after experiencing mild symptoms and being treated with antivirals, said LACDPH, adding that “close contacts of the infected person and other workers exposed at the worksite are being monitored for symptoms.”

While the LACDPH confirmed the H5 avian flu infection, further analysis is required to determine the exact subtype, although H5N1 is the most likely. A newer strain of H5N1, clade 2.3.4.4b, has raised global concern due to its widespread presence and mutations that may facilitate easier transmission in mammals.

The first case in Los Angeles follows the State of Emergency declared by California’s Governor Newsom due to a widespread dairy outbreak linked to avian influenza that had spread to Southern California. About two-thirds of all California dairy farms had experienced infections in cattle, according to data from the U.S. Department of Agriculture.

LINK: A list of all human cases of H5N1 bird flu since 2021

It also follows the first human cases reported in Arizona, Louisiana, Delaware, Wisconsin, and Iowa, as well as the first severe case of avian flu in the U.S., in a patient who was hospitalized in critical condition.

Globally, 88 human cases of H5N1 bird flu have been reported this year, including 73 in the United States and one in Canada. Almost half of the U.S. cases have been reported in California, with most linked to poultry or dairy exposure.