Latest on Zika Virus: WHO's Recommendations, CDC Advisory Expanded to 28 Countries

— -- The spread of the mosquito-borne Zika virus has become a world-wide concern, with the World Health Organization declaring it global health emergency on Monday. This is the first time the agency has used that classification since the deadly Ebola outbreak in West Africa.

Here's the latest on the virus, which has been linked to an alarming birth defect among newborns.

WHO Releases Recommendations After Issuing Global Health Emergency

The WHO has declared a global health emergency for the just the fourth time in the agency's history due to the ongoing Zika outbreak. The organization is now releasing recommendations for countries facing a Zika outbreak, including new travel measures.

The recommendations include improving communications so that an affected community is reporting possible cases, increasing surveillance of Zika virus infections and taking measures to control the mosquito population.

Additionally, WHO has advised travelers be updated about the potential risks, but that trade between countries should not be disrupted by the outbreak.

CDC Issues Travel Advisory for Total of 28 Countries, Territories

The U.S. Centers for Disease Control and Prevention has expanded travel advisories for a total of 28 countries and territories where there are reports of the Zika virus currently being transmitted from mosquitoes to humans.

The four new additions to the list announced Monday are American Samoa, Costa Rica, Curacao and Nicaragua.

The CDC has advised pregnant women to consider postponing travel to a country with ongoing Zika virus transmissions. Women who are thinking about pregnancy are advised to consult with their health care provider before traveling to countries with Zika virus transmissions.

What Does the Virus Do?

Common symptoms of the Zika virus include fever, rash, joint pain and conjunctivitis, according to the CDC. Approximately one in five people infected with the virus show symptoms. Severe complications from the virus that require hospitalization are rare, according to the CDC.

The virus has also been associated with a rise of microcephaly birth defects in which an infant is born with an abnormally small head, which can cause significant developmental delays.

The CDC is also investigating if a rare paralysis syndrome called Guillain-Barre is related to the virus. The syndrome is an immunological reaction that can also occur after other viral or bacterial infections.