Ebola more complicated than many doctors realized

Even after nearly 40 years, Ebola is still finding ways to surprise us.

The world's largest Ebola outbreak, which began in December 2013 and is still simmering in West Africa, has taught doctors that the disease is even more complicated than previously believed.

Infectious disease experts shared some of what they've learned about Ebola over the past year with USA TODAY.

Ebola isn't necessarily a fatal disease.

Conventional wisdom says that fatality rates for Ebola range from 25% to 90%. But those statistics are based on outbreaks in Africa, where patients have limited access to modern hospital care. In the current West African outbreak -- which has largely affected Sierra Leone, Guinea and Liberia -- more than 28,200 people have been sickened and more than 11,300 have died, according to the World Health Organization.

Yet eight of 10 Ebola patients treated for Ebola in the USA last year survived.

Although there are still no approved drugs or vaccines for Ebola, doctors in the USA and Europe were able to save most of their patients through aggressive "supportive care" in the intensive care unit, said Bruce Ribner, medical director of Emory University Hospital’s serious communicable disease unit, which treated four Ebola patients. This care involved, among other things, closely monitoring patients' blood pressure and electrolytes, and providing intravenous fluids to prevent dehydration. One patient, physician Ian Crozier, was hospitalized at Emory for more than a month, requiring a ventilator and kidney dialysis.

Ebola doesn't always cause massive bleeding.

Ebola is known as a hemorrhagic fever because it often causes heavy bleeding, such as oozing from the gums and blood in stools. Only 18% of patients in the West African outbreak have experienced unexplained bleeding.

But in many ways, Ebola in this epidemic has resembled cholera, an often fatal bacterial illness that can cause massive diarrhea and vomiting, said Thomas Frieden, director of the Centers for Disease Control and Prevention. Ebola doesn't spread like cholera, which can be transmitted through contaminated water. Ebola spreads through direct contact with bodily fluids.

But Ebola patients treated at Emory lost up to 20 liters of fluid a day through diarrhea and vomiting, Ribner said. Patients with Ebola can die from losing so much fluid that they go into shock, he said. That makes IV fluids essential. At the height of the Ebola crisis last year, West African clinics were too overwhelmed to provide IV fluids.

Ebola can be sexually transmitted, even long after recovery.

Doctors have known for some time that Ebola can survive in semen for months after men recover from the illness. But it was never really known whether people could become infected through sex.

In March, a woman in Monrovia, Liberia became infected with Ebola after having sex with an Ebola survivor. She'd had no other contact with Ebola, according to the CDC. A 16-year-old girl in Sierra Leone died of Ebola earlier this month, also in an apparent case of sexual transmission.

The WHO now advises doctors to counsel Ebola survivors about the importance of safe sex and to give them condoms. Doctors should offer male survivors semen testing three months after they leave the hospital. If men test positive, they should be retested every month, until two Ebola tests show no sign of the disease.

Ebola can cause serious complications in survivors.

Doctors have carefully tracked the progress of Ebola survivors in West Africa.

Half of Ebola survivors have joint pain that can leave them too debilitated to work, the WHO announced in August. About 25% of survivors have eye complications, which can range from vision changes to uveitis, an inflammation inside the eye that can lead to blindness if not treated.