Brazilian Army soldiers stand at attention during a ceremony to mark their graduation from training on how to combat the Aedes aegypti mosquito in Rio de Janeiro, Brazil, February 12, 2016. [Photo/Agencies]

So far, over 4,000 cases of microcephaly in newborns have been registered in Brazil. Out of those, over 400 have already been confirmed.

So far, more than 500,000 people, including 222,000 soldiers, have been dispatched to help the mosquito eradication efforts in Brazil. They have already visited 23.8 million buildings nationwide, including private homes, public buildings and commercial properties.

So far, the Zika outbreak reportedly has affected more than 30 countries.

Colombia's national health institute on Saturday reported a total of 31,555 cases of the disease in the country, including 5,013 pregnant Colombian women infected with the mosquito-borne Zika virus, which continues its rapid spread across the Americas.

China confirmed its first imported case of the Zika virus on Tuesday, and its southwestern border province of Yunnan is on high alert, providing 24-hour laboratory tests for the virus.

Lu Lin, director of the Center for Disease Control and Prevention in Yunnan, said on Friday the center is able to obtain the test result in four hours.

He said the center has assessed risks of imported case of the Zika virus in all prefectures and cities in the province, which borders Myanmar, Laos and Vietnam.

Zika drew the attention of the WHO after it was discovered that pregnant women infected by the virus were giving birth to an increasing number of babies with microcephaly, a syndrome characterized by a smaller cranium, often accompanied by other health problems and cognitive delays.

The WHO said on Friday that possible Zika vaccines are expected to come out for large-scale clinical trials in at least 18 months, advising pregnant women to delay travel to areas where the Zika virus had turned up.

The world health body also said the possible link between the Zika virus and microcephaly in some new born babies is expected to be confirmed within weeks.