An Illinois male resident who traveled to Colombia in South America is the third case in the US of the mosquito-transmitted Zika virus, health officials said Friday. The Illinois Department of Public Health officials said the case was confirmed on Thursday but declined to provide further details, Reuters reported. Earlier this month, department officials reported that two pregnant Illinois residents who recently traveled to countries where the Zika virus was found had tested positive for the virus. Four Canadians who traveled to the affected countries have also been infected with the Zika virus. The Aedes mosquito-transmitted virus has been linked to brain damage called microcephaly, in which babies are born with abnormally small heads and brains that have not developed properly, in thousands of babies in Brazil. There is no vaccine or treatment yet.