External affairs ministry has confirmed that 13 Indians have tested positive for the Zika virus in Singapore, after an outbreak of the mosquito-borne disease that at first affected three dozen workers on a construction site.<br/><br/>Ministry spokesperson Vikas Swarup in response to a Reuters query said according to mission in Singapore 13 Indian nationals have tested positive for Zika. <br/><br/>US health officials have concluded that Zika infections in pregnant women can cause microcephaly, a birth defect marked by small head size that can lead to severe developmental problems in babies.