The Zika virus, which is quickly becoming a global problem, has made its way into more countries.
The CDC released more travel health notices Friday that named eight more countries in which the disease has spread via mosquito bites. These include Samoa, Cape Verde, and more countries in South America and the Caribbean.
The Zika virus is primarily transmitted by Aedes aegypti, the type of mosquito responsible for spreading dengue, yellow fever, and a whole host of other tropical infectious diseases.
Originally identified in 1947 in Uganda, Zika was relatively unknown until 2007, when there was an outbreak of the virus in Micronesia. The mosquitoes pick up the virus from infected people, according to the CDC.
There is no vaccine or treatment for Zika.
The increased presence of the virus, coupled with its connection with birth defects in babies whose mothers have been infected with the disease, has led to a number of CDC alerts and guidelines in recent weeks.
For example, the CDC’s travel notices are especially geared toward pregnant women, because of concerns about the virus’ connection to brain abnormalities in babies and other neurological conditions.
Brazil, one of the areas hit hardest by the disease, has had about 20 times normal amount of babies born with a condition called microcephaly in 2015 compared to 2014. This birth defect, in which the brain is abnormally small, was often found after the mother had Zika virus-like symptoms early in the pregnancy.
Researchers still aren’t sure whether the virus causes the birth defects, but there does appear to be a link. Earlier this week, the CDC issued interim guidelines for pregnant women travelling to countries where the disease is being transmitted, while some countries have gone as far as to advise citizens not to get pregnant.
Because Zika hasn’t posed a threat until very recently, there aren’t many treatments or vaccines in development, though companies are jumping on board to find possible ways to fight back against a possible epidemic. Others are trying to target the mosquito itself and kill it off to keep the disease from spreading, but it might be a while before those efforts are widely spread.
Here’s the list of the 22 countries and territories that have had local transmission of the Zika virus, so far:
- Cape Verde
- El Salvador
- French Guiana
- Puerto Rico
- Saint Martin
NOW WATCH: Briefing videos
Business Insider Emails & Alerts
Site highlights each day to your inbox.