Zika not an issue at Olympics: Rio health

The risk of Zika virus infections at the Olympic Games is low and shouldn't deter spectators, Rio health officials say.

Rio's Health Secretary Daniel Soranz says Zika cases have dipped significantly in recent months.

The mosquito-borne virus has been linked to the birth defect microcephaly and its discovery in Brazil last year led to concern over the Games, which are expected to attract some 500,000 visitors.

However, with dry and cooler weather in Rio amid the southern hemisphere winter, the incidence of Zika and other mosquito-borne diseases such as dengue and Chikungunya has declined sharply in recent months.

"Since two weeks before the Games, the number of cases were almost non-existent. In the city, cases are very rare and for us it is an issue that we have more than overcome," Soranz told reporters in Rio.

Zika is spread primarily through the bite of an infected mosquito, although it can also spread through sexual transmission.