Laos is the latest country to report a local transmission of Zika virus, according to the World Health Organisation, as fears mount over the mosquito-borne illness that has been linked to birth defects.
Asia has seen only a sprinkling of cases of the virus, but a surge in Latin America this year has pushed the UN health agency to declare Zika a global health emergency.
Laos joined a total of 41 countries that have reported local transmissions of the virus since the beginning the year, a WHO report said.
Health authorities in Laos, a rural Communist country with minimal infrastructure, were not available to comment.
Neighbouring Thailand reported one case last month of a 22-year-old who contracted the illness domestically and has since recovered.
Thailand's health ministry urged the public not to panic, saying there have been an average of five cases per year since 2012 with no outbreaks.
The sickness is carried by the Aedes aegypti mosquito, which also spreads dengue fever.
It breeds in tropical areas, including Southeast Asia, which has seen a spike in cases of dengue in recent months and most often causes mild, flu-like symptoms.
A growing body of evidence suggests Zika can also trigger microcephaly, a condition defined by unusually small heads in newborn babies that can result in developmental problems.
Brazil was first to sound the alarm on the apparent link with birth defects.
It has since become the hardest hit country, with an estimated 1.5 million cases of active Zika transmission and 641 confirmed cases of microcephaly.
Yesterday, scientists in the United States said they found the first concrete evidence of a link between the virus and the birth defect, which has so far been circumstantial.
The findings may help to identify drugs to prevent or cure the Zika virus, which currently lacks a vaccine or specific treatment.