The second case of a person contracting bird flu or H5N1 virus despite not being exposed to poultry or dairy cows has been reported, US health officials said. According to reports, this person had shared a home with a patient who was first hospitalized with bird flu in August.

About 7% of dairy workers exposed to the avian flu that is spreading through U.S. herds have become infected themselves, federal experts estimate. That number highlights concerns that circulating strains of bird flu might become highly infectious in humans,

Seven percent of tested workers on dairy farms where cows were infected with bird flu caught the virus themselves, according to a new study.

The CDC said Thursday it is updating its recommendations for testing, treatment and protection for workers who may be exposed animals infected with bird flu.