A third farmworker has tested positive for bird flu in California, according to the state’s health department. If confirmed by the US Centers for Disease Control and Prevention, this would be the 17th human case of H5N1 flu in the US since March,

STAT recently spoke to Erica Pan, California’s state epidemiologist, about what public health officials are doing to monitor for human H5N1 infections. The conversation, which took place before California announced its human cases, has been lightly edited for clarity and length.

Both patients were dairy workers whose illnesses were mild. Investigators are continuing to evaluate the contacts of a Missouri patient who had no exposure to animals.