Well over a year since the global fears over the Ebola epidemic sent US stocks reeling in late 2014 ahead of an even sharper rebound, today the head of the World Health Organization delivered a very stern warning when she said that the 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 level of alarm is extremely high," WHO director general Margaret Chan said Thursday in an e-mailed statement according to Bloomberg. Chan said she will convene an emergency meeting on Feb. 1 in Geneva to consider whether to declare the outbreak a "Public Health Emergency of International Concern," which can coordinate government responses to direct money and resources at the virus. She added that the spread of the mosquito-borne disease had gone from a mild threat to one of alarming proportions.