BRATISLAVA: A Slovak woman returning from South America was confirmed as the first case of the Zika virus in the country, Slovak Health Minister Viliam Cislak said on Wednesday.

The World Health Organization declared the Zika outbreak linked to thousands of birth defects in Brazil an international health emergency on Feb. 1, although much about the virus remains unknown.

"Test results of the patient hospitalised with a suspected Zika virus last week in Presov, eastern Slovakia, were positive," Cislak told reporters.

"The patient is in good health and does not require further treatment," he said.

The first two cases of the mosquito-borne Zika virus were confirmed last week in the neighbouring Czech Republic, in a man returning from Martinique and a woman who travelled to the Dominican Republic.

Much remains unclear about the virus, including whether it causes microcephaly in babies, a condition defined by unusually small heads that can result in developmental problems.