BANGKOK - Thai health authorities said Friday that microcephaly in two babies was caused by the Zika virus, in what is believed to be Southeast Asia's first confirmed case of a link between the sickness and the birth defect.
"Two of the three infants (tested) had microcephaly due to the Zika virus," Health Ministry official Wicharn Pawan told AFP.
The World Health Organisation (WHO) this week said any confirmed cases in Thailand would be the first identified in Southeast Asia.
Zika causes only mild symptoms in most, including fever, sore eyes and a rash. But pregnant women with the virus risk giving birth to babies with microcephaly -- a deformation that leads to abnormally small brains and heads.
Thai authorities had monitored 36 pregnant women infected with the virus.
Earlier this week Thai doctors cleared two other babies with the condition of a link to Zika, a virus spread mainly by mosquitoes.
Scientists warned this month that the world should prepare for a "global epidemic" of microcephaly as the virus takes root in new countries.
Thailand expects up to 17 per cent of its GDP to be generated from tourism by the end of this year and a Zika outbreak could dent visitor numbers.
On Friday the US's Centers for Disease Control and Prevention (CDC) issued a travel advisory urging pregnant women to "consider postponing nonessential travel to Southeast Asia countries with reports of Zika virus".
Virologist Praset Thongcharoen said "4.3 infants per 100,000," are born with microcephaly in Thailand, twice the global average.
The condition can also be caused by Down syndrome and other infections during pregnancy such as German measles and chickenpox.