Dairy workers who’ve been exposed to bird flu should be tested for the virus even if they don’t have symptoms and be offered Tamiflu to cut their risk of getting sick, the Centers for Disease Control and Prevention said Thursday.

An eagerly anticipated serology study in farm workers exposed to H5N1-infected dairy cattle shows that 7% had antibodies suggesting prior infection, findings that today triggered enhanced testing, prophylactic (preventive) treatment, and use of personal protective equipment (PPE) from the US Centers for Disease Control and Prevention (CDC).

Public health experts are concerned that the first detection of H5N1 bird flu in a pig could mean the next step in human-to-human transmission of the virus.

The CDC recommends wider testing and more use of antiviral flu medicine for workers exposed to bird flu at poultry and dairy farms.

Federal health officials on Thursday called for more testing of employees on farms with bird flu after a new study showed that some dairy workers had signs of infection, even when they didn't report feeling sick.

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.

Farm workers who have been exposed to animals with bird flu should be tested for the virus even if they do not have symptoms, the U.S. Centers for Disease Control and Prevention said on Thursday.

After a new study showed that bird flu has spread to dairy farm workers more often than previously known, the US Centers for Disease Control and Prevention is expanding its recommendations for testing and treatment of workers on farms where animals have tested positive.

Federal health officials are calling for more testing and treatment of workers on farms with bird flu. The new guidance comes after a study showed that some dairy workers had signs of infection, even when they didn’t report feeling sick.