Singapore said on Thursday it did not know if the Zika virus detected in the country could cause the same birth defects and other disorders linked to an outbreak in Latin America.
A DNA analysis of the mosquito-borne virus, which has infected almost 300 people in Singapore, including two pregnant women, revealed slight differences between the strains but it was not clear what that meant in terms of the severity of the disease, the health ministry said.
The World Health Organisation (WHO), which has declared Zika an international health emergency, says more research is needed to determine the effects of the different Zika strains.
"There is no evidence from existing studies and from this sequence to indicate whether the differences between these strains and the South American virus correlate with differences in severity or type of disease," the health ministry said.
"Correlation of virus strains with specific clinical manifestations will take long-term careful epidemiological studies as well as experimental studies," it added.
The WHO has said that infection with the virus in pregnant women can cause the birth defect microcephaly, in which the brain and head of the baby are undersized, and other severe brain abnormalities.