Zika-Linked Birth Defects a Global Health Emergency, WHO Says

February 01, 2016

The World Health Organization (WHO) today declared outbreaks of microcephaly and other neurologic abnormalities that may be linked to the Zika virus a "public health emergency of international concern," the same designation given to the Ebola outbreak 2 years ago.

The virus, spread by the Aedes aegypti mosquito, is strongly suspected of causing microcephaly in thousands of newborns in Brazil. Public health authorities also are investigating whether the virus has triggered cases of Guillain-Barré syndrome.

The WHO's declaration of a global emergency will set in motion coordinated efforts to intensify mosquito control, develop tests and vaccines for the virus, and determine whether Zika indeed causes microcephaly and other neurologic problems.

WHO Director-General Margaret Chan, MD, said in a news conference that her agency was compelled to take action even though the microcephaly–Zika link had yet to be established. "Can you imagine if we don't do all the work now and wait until the scientific evidence comes out?" said Dr Chan, who had been criticized for responding to the Ebola crisis too slowly. "People will say 'Why didn't you take action?' because the mosquito is ubiquitous."

The evidence for the link between Zika and microcephaly, she said, was strong and growing.

The Zika virus alone would not justify a declaration of emergency, she added. For most people, "Zika is not a clinically serious infection." Roughly one in five individuals with the virus will develop symptoms such as fever, rash, joint pain, and conjunctivitis, and those generally disappear within a week without landing anyone in the hospital, according to the Centers for Disease Control and Prevention (CDC).

Last week, Dr Chan had warned that the virus was "spreading explosively" in the Americas. Another WHO official said the virus could infect 3 million to 4 million people in the coming months — a prediction all the more troubling in light of Brazil hosting the Summer Olympics in Rio de Janeiro this August.

The CDC is advising pregnant women to postpone travelling to 28 countries and territories where mosquitos are transmitting the virus. Twenty-five are in Latin America and the Caribbean. The other three are Cape Verde off the coast of Africa and Samoa and American Samoa in Polynesia. Cases of microcephaly and other neurologic birth defects have followed recent Zika outbreaks in French Polynesia, according to WHO.

So far, Zika is not considered endemic in the United States. The only cases reported here involve people who have recently visited areas subject to the CDC's travel warning. The CDC expects that mosquitos will eventually transmit the virus in the United States. However, the CDC said last week that it anticipates smaller outbreaks than those seen in Latin America, given less densely populated urban areas, greater use of air conditioning, and more widespread mosquito control measures in the United States.

The WHO's Dr Chan declared the public health emergency on the basis of the recommendations of a special committee on Zika that the agency convened last week. Committee members include two US physicians: David Freedman, MD, a professor of medicine and epidemiology at the University of Alabama in Birmingham, and Jennifer Staples, MD, PhD, a medical epidemiologist with the CDC. James Meegan, PhD, director of the Office of Global Research at the National Institute of Allergy and Infectious Diseases, is a committee adviser.

Dr Chan accepted all the committee's recommendations on how to deal with the birth defect crisis that Zika may have produced. The committee said there should be no restrictions on trade or travel with any country or territory where mosquitoes are transmitting the virus. Travelers, however, should be apprised of the risks of visiting Zika hot spots and take precautions against mosquito bites. In addition, aircraft and airports should follow standard WHO recommendations on how to eliminate any insects.


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