The unidentified man, 25, lives in Lien Chieu District and is under treatment, Pham Hung, head of the General Department of Preventative Medicine’s department for communicable disease control, said on Monday.

The Zika virus is primarily spread through mosquitoes and potentially transmitted sexually, from mother to child and through blood transfusion.

The disease it causes, Zika fever, produces mild symptoms like fever, red eyes, joint pain, headache, or rash in humans. But it is known to cause microcephaly and other brain malformations in some babies born to mothers infected during pregnancy.

Microcephaly causes an abnormally small head, intellectual disability and poor motor and speech functions. There is no vaccine yet against Zika.

Vietnam’s first reported case of Zika virus infection was in 2016 in the south-central province of Khanh Hoa. By early 2017 the country recorded 265 cases.

One baby was born with microcephaly linked to the Zika virus in the Central Highlands province of Dak Lak in 2016.

Like other diseases transmitted by mosquitoes, Zika virus outbreaks occur mostly during the rainy season.

In Vietnam, most cases have been recorded in the south but also in the central region and the Central Highlands.