FREEHOLD TOWNSHIP - The U.S. is advising Americans not to travel to certain West African countries as the deadly Ebola outbreak is claiming more lives.

More than 700 people have died from Ebola, which begins with flu-like symptoms and then progresses to massive internal bleeding.

Infectious disease specialist Georgios Giannakopoulos, of CentraState HealthCare, says about 80 to 90 percent of those infected with the disease die from it.

Ebola is spread through contact with body fluids, including sweat. A patient is only contagious once symptoms start. Giannakopoulos says it can take up to 14 days for symptoms to show up.

Concerns about travelers bringing the Ebola virus into the U.S. have prompted the Centers for Disease Control and Prevention to warn against non-essential travel to Liberia, Guinea and Sierra Leone, where most cases have occurred.

The CDC has quarantine centers across the U.S., including one in Newark. 

The outbreak has put doctors on notice. "Before we started by saying, 'tell me about your symptoms and your past medical history'," Giannakopoulos says. "Now we're going to start saying, 'tell me first about your travel history and then we're going to discuss what you're here for'."

The CDC says the disease is spreading in West Africa, but there has never been a confirmed case in a developed country.

There is no cure for Ebola, doctors can only treat the symptoms and hope for the best.