Zika ‘spreading explosively’ in Americas as WHO raises alarm

(Bloomberg) — Zika virus, a mosquito-borne pathogen that may cause birth defects when pregnant women are infected, has been “spreading explosively” in South and Central America, the head of the World Health Organization (WHO) said Thursday.

“The level of alarm is extremely high,” WHO director general Margaret Chan said Thursday in an e-mailed statement.

Chan emphasized that researchers are still working to determine the exact link between the virus and birth defects. “The possible links, only recently suspected, have rapidly changed the risk profile of Zika, from a mild threat to one of alarming proportions,” Chan told members of the WHO executive board in Switzerland.