Zika virus

Around the fifth month of her pregnancy, Daniele Ferreira dos Santos fell ill with a high fever and angry red splotches on her skin.

Zika virus is transmitted to people through the bite of an infected Aedes species mosquito. These are the same mosquitoes spreading dengue and chikungunya viruses.

World Health Organization officials said Thursday the virus is "spreading explosively" and the Americas could see up to 4 million cases of Zika in the next year.

The disease seems to be related to birth defects in Brazil.

The alert issued Friday by the Atlanta-based Centers for Disease Control and Prevention covers 14 countries and territories in the Americas where the Zika virus has been detected.