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The deadliest Ebola(埃博拉病毒) outbreak in recorded history is happening right now. The outbreak is unprecedented(空前的) both in the number of people who have gotten sick and in the geographic scope. And so far it’s been a long battle that doesn’t appear to be slowing down.

Ebola is both rare and very deadly. Since the first outbreak in 1976, Ebola viruses have infected thousands of people and killed roughly killed 60 percent of them. Symptoms can come on quickly and kill fast.

The current outbreak started in Guinea sometime in late 2013 or early 2014. It has since spread to Sierra Leone and Liberia, including some capital cities. And one infected patient traveled on a plane to Nigeria, where he spread the disease to several others and then died. Cases have also popped up in various other countries throughout the world, including in Dallas and New York City in the United States.

The Ebola virus has now hit many countries, including Guinea, Liberia, Sierra Leone, Nigeria, Senegal, and the United States. The virus, which starts off with flu-like symptoms and sometimes ends with bleeding, has infected about 6,500 people and killed more than 3,000 since this winter, according to the World Health Organization on September 30, 2014.

There are some social and political factors contributing to the current disaster. Because this is the first major Ebola outbreak in West Africa, many of the region’s health workers didn’t have experience or training in how to protect themselves or care for patients with this disease.

Journalist David Quammen put it well in a recent New York Times article, “Ebola is more dangerous to humans than perhaps any known virus on Earth, except rabies(狂犬病) and HIV. And it does its damage much faster than either.”

Hopefully, researchers are working to find drugs, including a recent $50 million push at the National Institutes of Health. And scientists are working on vaccines(疫苗), including looking into ones that might be able to help wild chimpanzees, which are also susceptible to the disease. The first human Ebola vaccine trial is scheduled to start in the spring of 2015.