The head of the UN's public health body has blamed inadequate mosquito control policy for the proliferation of the virus. Europe is at risk of a Zika outbreak, according to the WHO's latest assessment.
WHO Secretary-General Margaret Chan on Monday blamed "massive policy failure" for the spread of the mosquito-borne virus Zika across many parts of North and South America.
"The spread of Zika, the resurgence of dengue and the emerging threat from chikungunya are the price being paid for a massive policy failure that dropped the ball on mosquito control in the 1970s," Chan said during her speech to the 69th World Health Assembly.
The WHO chief noted that the "failure to provide universal access to sexual and family planning services" revealed an "extreme consequence" of the Zika virus outbreak.
"The rapidly evolving outbreak of Zika warns us that an old disease that slumbered for six decades in Africa and Asia can suddenly wake up on a new continent to cause a global health emergency," Chan added.
In April, US officials announced that that there was a likely link between Zika and a rise in newborns with microcephaly, a rare condition resulting in a smaller head than normal. The WHO has investigated the link between the virus and the medical condition.
More than 1.5 million people have been infected with Zika in Brazil, with over 1,000 cases of microcephaly registered since last year, according to AFP news agency.
The mosquito-borne virus has also been reported in several countries in the Americas and the Caribbean, including Colombia, Haiti and Mexico.
Earlier this month, the WHO officials warned "there is a risk of spread of Zika virus disease in the European region."
The UN's public health body said an outbreak was more likely in countries where Aedes mosquitoes are present.
"With this risk assessment, we at WHO want to inform and target preparedness work in each European country based on its level of risk," said Dr. Zsuzsanna Jakab, the WHO's regional director for Europe.
"We call particularly on countries at higher risk to strengthen their national capacities and prioritize the activities that will prevent a large Zika outbreak," added Jakab.