A four-month-old baby in Vietnam's central Dak Lak province is the first case, a statement on the website of the country's General Department of Preventive Medicine said.
This is the case of a child with congenital malformations, suffering from a small head, most likely related to the Zika virus, the statement read. It noted that the child's mother had been diagnosed with the Zika virus, as had other members of their household.
In March, the country reported the first cases of adults infected with the virus; it has so far reported nine cases. The health department says the country has made a very active push into the provinces to spread the word about preventing and identifying Zika.
Zika infections during pregnancy are linked to microcephaly, a debilitating birth defect in which the head and brain are undersized, as well as other issues. The connection between the virus and microcephaly was first made during an outbreak in Brazil, which has so far reported nearly 2,000 cases of microcephaly in the past year that it blames on the virus.
Thailand reported two cases of microcephaly due to Zika last month, and health authorities said the number of infections this year has so far reached 200. Myanmar reported its first case days ago, detected in a pregnant foreign woman.
Zika, a mosquito-borne virus that is also sexually transmitted, has been reported in 70 countries, according to the World Health Organization. There is no vaccine or specific course of treatment for the virus.