MONDAY, Jan. 25, 2016 (HealthDay News) -- The mosquito-borne Zika virus, which has harmed thousands of babies born in Brazil, will likely spread to all but two countries in North, Central and South America, the World Health Organization warns.
Transmission is probable because the Aedes mosquitoes, which spread the virus, populate the entire region except for Canada and continental Chile. Also, the "population of the Americas had not previously been exposed to Zika and therefore lacks immunity," according to a WHO statement released Sunday.
Meanwhile, organizers of the Summer Olympics 2016 in Brazil said they'll be on high alert to prevent Zika transmission.
According to the Associated Press, the committee plans daily inspections of the Olympic and Paralympic sites to seek out stagnant waters where Zika-spreading mosquitoes could breed. The games are scheduled for Aug. 5-21.
"Rio 2016 will continue to monitor the issue closely and follow guidance from the Brazilian Ministry of Health," the committee said in a statement.
Since last May, 21 countries and territories in the Americas have reported cases of Zika, which is linked to a brain disorder called microcephaly. Babies with the condition have abnormally small heads, resulting in developmental issues and, in some cases, death.
Preventing mosquitoes from breeding, and protecting yourself from mosquito bites, is the best protection, the WHO said.
The situation has led the U.S. Centers for Disease Control and Prevention to expand a recent travel advisory. Pregnant women are warned to avoid trips to Bolivia, Brazil, Cape Verde, Colombia, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname, Samoa, Venezuela and Puerto Rico. The agency also recommended screening for women who have recently traveled to these places while pregnant.
The CDC has also said that cases of the neurological disorder Guillain-Barre syndrome have been reported in patients with probable Zika virus infection in Brazil and French Polynesia, although more study is needed to confirm the link.
The American College of Obstetricians and Gynecologists (ACOG) -- the largest organization representing obstetricians and gynecologists in the United States -- said last week that it supports the guidelines aimed at shielding pregnant women from the mosquito-borne Zika virus.
According to a statement, ACOG is urging pregnant women and those planning a pregnancy to follow Zika virus travel and health guidelines recently issued by the CDC.
"Travel to regions with ongoing Zika virus outbreaks is not recommended for women who are pregnant or women who are considering pregnancy," ACOG President Dr. Mark DeFrancesco said in the statement.
The CDC said doctors should ask all pregnant patients about recent travel and specific symptoms, such as a sudden fever or rash. If Zika virus infection is possible, doctors should have the patient tested for the virus.
If tests reveal signs of infection, ultrasounds should be considered to monitor the fetus' development, and referral to a maternal-fetal medicine or infectious disease specialist with expertise in pregnancy management is also recommended, the CDC advised.
There is no vaccine or treatment for Zika, and symptoms are usually mild in healthy adults.
According to ACOG's DeFrancesco, "there is much that we do not yet know about the Zika virus and its effects during pregnancy, for example, whether pregnant women are of greater risk of infection than non-pregnant individuals. However, because of the associated risk of microcephaly, avoiding exposure to the virus is best. That's why pregnant women and women who are considering pregnancy should delay planned travel to areas where Zika virus outbreaks are ongoing."
Because there is no treatment for Zika virus at this time, "women should be counseled about all options available to them," he said. "When possible, delivery at a center with the appropriate levels of neonatal expertise may be warranted," he suggested.
The U.S. Centers for Disease Control and Prevention has more about the Zika virus.