GENEVA (AP) — The U.N. health agency says reports from national authorities indicate no confirmed laboratory cases of the Zika virus in anyone associated with the Rio Olympics.

The World Health Organization announced the findings Thursday in its weekly situation report on Zika. A recent epidemic of the mosquito-borne virus, which first erupted in Brazil, has been linked to brain-related birth defects in newborns and other nervous system troubles in some adults.

Before the Games, some medical experts expressed concerns the Games might cause the virus to spread faster than normal by drawing large numbers of foreign athletes and visitors who might carry it back home. The virus can also be spread through sex.

Some Brazilian fans jeered U.S. athletes who made light of the risk or stayed home over fears about Zika.