ATLANTA — The US Centers for Disease Control and Prevention (CDC) confirmed two new human cases of H5N1 in California — the first time the state has reported the disease in people. The California Department of Public Health (CDPH) noted that there was no known point of contact between the two workers, both located in the Central Valley area, and that their symptoms remained mild.

California began reporting outbreaks of the bird flu in dairy cattle in August. Close to 60 Californian dairy herds have been affected by the virus since then, according to the US Department of Agriculture.

Even with the two new human cases of H5N1, CDC has not changed its risk assessment for the general public, which remains low.

“At this time, there is no known link or contact between the first and second confirmed cases in California, suggesting these are separate instances of animal-to-human spread of the virus,” CDC said.

Including these two cases, the total number of people in the United States who have contracted the disease this year is 16. Symptoms include eye redness, mild flu-like upper respiratory symptoms, fever, cough, sore throat, difficulty breathing, runny or stuffy nose, and muscle aches.

Human cases have also been reported in Texas (1), Michigan (2), Colorado (10) and Missouri (1). Six of these cases have been linked to exposure to infected dairy cattle, while nine are connected with exposure to infected poultry. The source of the infection for the case in Missouri has still yet to have been determined, noted CDC.

The agency is continuing to investigate the two most recent cases with the collaboration of California and other public health officials. In the coming days, CDC plans to conduct additional characterization of the viruses, including sequencing, isolating and growing the viruses.