SANTA ANA, Calif.

— Travelers in the United States and Puerto Rico are at greater risk of getting Zika virus infection as they travel to areas where there are high levels of mosquitoes, the Centers for Disease Control and Prevention announced Wednesday.

In Puerto Rico, which has been hit hard by the outbreak, more than 6,300 people have tested positive for Zika, which is known as microcephaly.

The CDC reported Wednesday that more than 5,300 of those infections have occurred in the state.

More than 30,000 people have been infected in the U.S. mainland, including 3,700 in Puerto Rico.

The Centers for Medicare & Medicaid Services said that people in Puerto Rican health care facilities and health care workers in areas of the U,S.

Virgin Islands and Puerto Ricos most at risk of infection should get tested.

The virus can spread through direct contact with an infected person, such as coughing or sneezing, and through indirect contact such as sharing a bathroom with an individual who has been exposed to the virus.

Travelers with more than 3,000 virus tests are recommended to seek medical attention.

The CDC said more than 4,800 people in the continental U.s. have been vaccinated against the virus and more than 1,400 are now being tested.

People in Puerto Ricas health care systems should be tested if they have been in a health care facility for a while.

Puerto Rico has had its largest outbreak of the virus since March and has been dealing with a surge of cases and deaths in the months since.

The state is in the midst of a government shutdown, but Gov.

Alejandro Garcia Padilla said Wednesday that the U .

S. government will be back in session Thursday.