Mosquitoes have infected two women with the Zika virus in Vietnam, health authorities said on Tuesday, in the country's first cases of a disease linked in Brazil to thousands of suspected cases of microcephaly, a rare birth defect.

A 64-year-old woman in the beach city of Nha Trang and a pregnant 33-year-old in Ho Chi Minh City fell sick in late March, and three rounds of tests have confirmed they are Zika-positive, health officials said.

The sufferers are in stable condition and no further infections have been found among their relatives and neighbors, the health ministry said in a statement.