Two women in Vietnam have been infected with the Zika virus, health ministers have announced. The younger of the patients is eight weeks pregnant, they added.

The Zika virus, which is carried by mosquitoes and transmitted to humans, is thought to cause microcephaly. Characterised by unusually small heads, microcephaly can result in developmental problems in babies. It is not clear if either of the women have recently travelled abroad, or whether they were infected with Zika in Vietnam.

A 64-year-old from the popular beach resort of Nha Trang became the country’s first confirmed case after being admitted to hospital complaining of fever, headache and a rash on her legs. ‘She tested positive to Zika virus on 31 March 2016 at Nha Trang’s Pasteur Institute,’ and the results have been confirmed by further testing, Vietnam’s health ministry said in a statement.

The second confirmed case was a 33-year-old woman who lived in Vietnam’s southern business hub Ho Chi Minh City. ‘She had symptoms including a rash, conjunctivitis, and fatigue,’ the statement said, adding that she tested positive for Zika last Thursday. Some 1,215 samples have been sent for testing for suspected Zika in 32 provinces throughout the country, according to the online Vnexpress newspaper.

The sufferers are in stable condition and no further infections have been found among their relatives and neighbours, it was confirmed today. ‘After investigations, we consider the source of infection could be mosquito,’ Deputy Health Minister Nguyen Thanh Long said. ‘She is eight weeks pregnant,’ he added in a Vietnam Television broadcast, but gave no details of the first woman.