Last Updated Feb 1, 2016 4:22 PM EST
The World Health Organization has announced that the explosive spread of the Zika virus in the Americas qualifies as a global health emergency, a declaration that is expected to trigger increased funding and coordinated efforts to help stop the outbreak.
The agency convened an emergency meeting of independent experts on Monday to assess the outbreak after Brazil reported a troubling link between the spread of Zika virus and a surge in the number of babies born with abnormally small heads, a birth defect known as microcephaly.
"After a review of the evidence, the committee advised that the clusters of microcephaly and other neurological complications constitute an extraordinary event and public health threat to other parts of the world," WHO Director-General Margaret Chan said.
Although Chan said there was no definitive proof that the Zika virus, which is spread by mosquitoes, is responsible for the birth defects, she acknowledged on Thursday that "the level of alarm is extremely high."
CBS News foreign affairs analyst Pamela Falk reports that the declaration means resources will be marshaled to aid in research, identification and the development of treatments, as well as to help stop the spread of the virus.
Falk noted that the committee issued its decision a day sooner than expected, showing a sense of the urgency in dealing with a rapid spread of the disease.
"The WHO is the lead agency, but the designation as an international public health emergency will involve UNICEF, Humanitarian Affairs (OCHA) and the world development program (UNDP) along with the U.N. as a whole, to now deal with the crisis," Farhan Haq, deputy spokesman for the Secretary General, told CBS News.
WHO estimates there could be up to 4 million cases of Zika in the Americas in the next year. So far, the only cases reported in the U.S. have been in travelers who contracted it abroad, but experts believe it's only a matter of time before the illness spreads here.
However, Dr. Anthony Fauci, director of the U.S. National Institutes of Health's National Institute of Allergy and Infectious Diseases said that he did not expect to see a major Zika outbreak in the U.S.
"If Zika acts like the other types of viruses that are mosquito-borne that we've had experience with, like dengue and chikungunya, we will see mini-outbreaks like in Florida and in Texas that can be well controlled with mosquito vector control. Hopefully we will not see anything worse than that, but we have to be very vigilant," Fauci told "CBS This Morning" last week.
The U.S. is also ramping up work to develop a Zika vaccine, a process that could take several years. There is currently no vaccine and no treatment for the illness.
The last time the WHO declared a public health emergency was for the devastating 2014 Ebola outbreak in West Africa, which killed more than 11,000 people. WHO came under fire for its slow initial response to Ebola, failing to declare a global health emergency until hundreds of people had already died.
"Of course, the world and the World Health Organization have all learned from the Ebola crisis," WHO spokesman Christian Lindmeier said earlier Monday before the emergency was declared. "That's why we are trying to bring in the best experts we can gather for this event, to try to establish what steps to take and what the way forward should be."
WHO officials say it could take six to nine months before science can definitively prove or disprove any connection between Zika and the spike in the number of babies born in Brazil with abnormally small heads.
"What we know so far is that the only microcephaly cases we see currently are from Brazil," Lindmeier said, noting that abnormally small heads in newborns can have many causes - such as the effects of herbicides, alcohol use, or drugs and toxins. "This is exactly what is the concerning question: why do we see this in Brazil?"
Jimmy Whitworth, an infectious diseases expert at the London School of Hygiene and Tropical Medicine, said we might soon see more babies born with the problem elsewhere as the virus becomes entrenched in other countries.
"It could be that we're getting the strongest signal in Brazil," he said before WHO's annoucement. "But having these cases occurring and pinning it to Zika is tough."
The U.S. Centers for Disease Control and Prevention says pregnant women should consider avoiding travel to places where Zika is spreading, and all visitors to those areas should take care to protect themselves against mosquitoes. On Monday, it added four more countries and territories to the advisory list, which now includes:
- In Latin America: Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Suriname and Venezuela.
- In the Caribbean: Barbados, Curacao, the Dominican Republic, Guadeloupe, Haiti, Martinique, St. Martin, Puerto Rico, the U.S. Virgin Islands.
- Cape Verde, off the coast of western Africa.
- Samoa and American Samoa in the South Pacific.