global health officials race good understand zika virus behind major outbreak begin brazil last year spread almost 60 countries follow question answer virus current outbreak people become infect zika transmit people bite infect female mosquitoes primarily aedes aegypti mosquito type spread dengue chikungunya yellow fever pan american health organization paho say aedes aegypti mosquitoes find countries americas except canada continental chile virus likely reach countries territories region aedes mosquitoes find virus also transmit sex either male female partner infect case apparent infection via blood transfusion report treat zika treatment vaccine zika infection company scientists race develop safe effective vaccine zika preventative shoot expect ready widespread use least two three years dangerous u.s. center disease control prevention conclude infection zika virus pregnant women cause birth defect microcephaly condition define unusually small head result developmental problems severe brain abnormalities baby cdc say since causal relationship establish several important question must still answer study could take years world health organization update assessment say likely explanation zika virus infection pregnancy cause congenital brain abnormalities include microcephaly addition agency say infection trigger guillain-barre syndrome gbs rare neurological disorder result paralysis update come consider months research previous statement base rapid assessment evidence say strong scientific consensus zika virus cause gbs microcephaly neurological disorder brazil recently report 1,835 confirm case microcephaly believe link zika infections pregnant women investigate 3,200 suspect case microcephaly current research indicate great microcephaly risk associate infection first trim pregnancy health officials warn impact could see late weeks recent study show evidence zika amniotic fluid placenta fetal brain tissue symptoms zika infection people infect zika may mild fever skin rash conjunctivitis muscle joint pain fatigue last two seven days many 80 percent people infect never develop symptoms zika contain efforts control spread virus focus eliminate mosquito breed sit take precautions mosquito bite use insect repellent mosquito net u.s. international health officials advise pregnant women avoid travel latin american caribbean countries section miami florida unite state singapore may expose zika also advise men women travel zika outbreak areas use condoms abstain sex six months prevent sexual transmission virus widespread outbreak active zika outbreaks report least 58 countries territories americas accord u.s. center disease control prevention cdc brazil country affect 1.usa.gov/1ovajyh africa cape verde americas 48 anguilla antigua barbuda argentina aruba bahamas barbados belize bolivia bonaire brazil british virgin islands cayman islands colombia costa rica cuba curaçao dominica dominican republic ecuador el salvador french guiana grenada guadeloupe guatemala guyana haiti honduras jamaica martinique mexico nicaragua panama paraguay peru saba puerto rico saint barthelmy saint lucia saint martin saint vincent grenadines saint eustatius st. maarten suriname trinidad tobago turks caicos unite state u.s. virgin islands venezuela asia singapore oceania/pacific islands american samoa fiji kosrae federate state micronesia marshall islands new caledonia papua new guinea samoa tonga history zika virus zika virus find tropical locales large mosquito populations outbreaks zika record africa americas southern asia western pacific virus first identify uganda 1947 rhesus monkey first identify people 1952 uganda tanzania accord complications associate zika zika also associate neurological disorder include serious brain spinal cord infections long-term health consequences zika infection unclear uncertainties surround incubation period virus zika interact viruses transmit mosquitoes dengue factbox zika virus cause alarm