The race is on to develop a Zika vaccine. The following are some questions and answers about the virus and the current outbreak.

How do people become infected?
The virus is transmitted to people through the bite of infected female mosquitoes, primarily the Aedes aegypti mosquito, the same type that spreads dengue, chikungunya and yellow fever. The Pan American Health Organization (PAHO) said Aedes mosquitoes are found in all countries in the Americas except Canada and continental Chile, and the virus will likely reach all countries and territories of the region where Aedes mosquitoes are found.

How do you treat Zika infection?
There is no treatment or vaccine available for Zika infection. Companies and scientists are racing to develop a safe and effective vaccine for Zika, but the World Health Organization said it would take at least 18 months to start large-scale clinical trials of potential preventative shots.

How dangerous is it?
The PAHO said there is no evidence that Zika can cause death, but some cases have been reported with more serious complications in patients with pre-existing medical conditions. The virus has been linked to microcephaly, a condition in newborns marked by abnormally small heads and brains that have not developed properly. It also has been associated with Guillain-Barre syndrome, a rare disorder in which the body's immune system attacks part of the nervous system.

What are the symptoms of Zika infection?    
People who get Zika virus disease typically have a mild fever, skin rash, conjunctivitis, muscle and joint pain and fatigue that can last for two to seven days. But as many as 80 percent of people infected never develop symptoms. The symptoms are similar to those of dengue or chikungunya, which are transmitted by the same type of mosquito.

How can Zika be contained?
Efforts to control the spread of the virus focus on eliminating mosquito breeding sites and taking precautions against mosquito bites such as using insect repellent and mosquito nets. US and international health officials have advised pregnant women to avoid travel to Latin American and Caribbean countries where they may be exposed to Zika.

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