As diseases go, Zika virus was always considered minor league. It didn’t make people all that sick; most infected people had no symptoms at all. Zika was confined to a relatively narrow belt that ran from equatorial Africa to Asia. Today, Zika has spread to Central and South America and is linked to an alarming increase in once-rare birth defects in Brazil. Although Zika was first diagnosed in Brazil in May, it’s been linked to more than 3,500 cases of microcephaly, in which infants are born with small heads and immature brain development.

Yet Brazil isn’t just fighting Zika. That country is also combating outbreaks caused by dengue and chikungunya viruses, which are known for causing fevers and debilitating joint pain. Dengue can be fatal. The USA needs to prepare for a similar scenario, in which epidemics of multiple mosquito-borne diseases break out simultaneously, according to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, who co-wrote a new report in The New England Journal of Medicine. FULL REPORT