Ebola is one of the deadliest diseases on Earth, with a fatality rate as high as 90%. It’s among a handful of illnesses so dangerous that governments consider them threats to national security. An epidemic in West Africa that began in late 2013 and faded in 2016 killed more than 11,000 people, exceeding the counts from all previous waves combined. Now Ebola has flared again, with the latest outbreak declared a global emergency by the World Health Organization.

1. What’s causing alarms?

In a new outbreak in the Democratic Republic of Congo that began in August 2018, more than 2,600 people have been infected and more than 1,800 killed -- making it the deadliest eruption since the last crisis ended. Several cases were confirmed in neighboring Uganda in June and two near Rwanda in July, raising fears of another wider contagion. Ebola disease is endemic to Congo, meaning it’s constantly present but generally under control.

2. Where does Ebola come from?

Scientists say the virus that causes Ebola jumps to humans through contact with secretions from animals such as chimpanzees, gorillas and bats that are infected with it. The virus passes among people through direct contact with the bodily fluids of someone who is infected with the disease or has died from it. Medical workers and family members are the most at risk. Ebola doesn’t travel through the air, making it less easily transmitted than many other pathogens, as long as proper health-care practices are followed.

3. How does it affect people?

According to the WHO, symptoms of Ebola can include fever, fatigue, muscle pain, sore throat and headache, followed by diarrhea, vomiting and sometimes bleeding inside and outside the body. It damages the immune system and organs, leading to massive internal bleeding and death from multi-organ failure and shock. In the latest outbreak, two-thirds of the people with confirmed infections have died.

4. How is Ebola treated?

Tackling symptoms early on increases the patient’s chances of survival. This includes administering fluids and body salts intravenously to prevent dehydration, providing oxygen, and using drugs to support blood pressure and control vomiting and diarrhea. There are no approved drugs for treating Ebola, although some therapies in development are showing promise. An experimental treatment from U.S. drugmaker Regeneron Pharmaceuticals Inc. is helping infected patients survive the virus. Preliminary results from the drug were so positive that the clinical trial was stopped early to get it to Ebola patients sooner.

5. Can you be immunized against it?

An experimental vaccine by Merck & Co. has proved effective in human trials at fending off the disease. It has already been given to at least 143,000 people in the latest outbreak, according to a report from Congo’s Ministry of Health. The remaining supply could be doubled to about 500,000 by splitting doses in half, an approach that was proven effective when used in Guinea. Merck also plans to make about 100,000 more doses by January, which could also be doubled, the report said. The WHO has also backed the introduction of Johnson & Johnson’s vaccine candidate, which would likely be used outside the hot zone -- where transmission is highest -- to prevent Ebola’s spread to adjoining areas.

6. What’s it mean to be a global emergency?

In declaring the current outbreak an international public health emergency on July 17, WHO Director General Tedros Adhanom Ghebreyesus said the organization had become more concerned the virus could spread outside Congo. The declaration can help mobilize international response to an outbreak, provide more resources, and focus government attention on the issue. The WHO said in late July that funding to fight the outbreak needs to triple to $324 million. Violence and mistrust in Congo are adding to the difficulties of containing the disease.

7. How far could Ebola spread?

Congolese President Felix Tshisekedi has appointed Jean-Jacques Muyembe, the chief of the country’s biomedical research institute and a veteran in battling Ebola, to head the government’s response. Muyembe says he can bring the disease under control by the end of 2019. In the previous big epidemic, Ebola spread from three epicenter countries -- Guinea, Liberia and Sierra Leone -- to Nigeria, Senegal and Mali. And, for the first time, Ebola infection occurred outside Africa. That provoked panic in Europe and the U.S., but in all there were just 11 cases and two deaths from Ebola in America.

--With assistance from William Clowes, Paul Richardson and John Lauerman.

To contact the reporters on this story: Albertina Torsoli in Geneva at atorsoli@bloomberg.net;Mike Cohen in Cape Town at mcohen21@bloomberg.net

To contact the editors responsible for this story: Paul Richardson at pmrichardson@bloomberg.net, Andy Reinhardt

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