There is no cure for Ebola yet, and when the Centers for Disease Control worry about disease that travels, they worry most about Ebola and there's been an outbreak of Ebola in the East African nation of Uganda.
ABC's Martin Seemungal has just been to Uganda, where more than a hundred and fifty people have died so far including some of those trying hardest to contain it.
She struggles to breathe, barely has the strength to cry out.
One of the world's deadliest viruses is attacking every organ in her body. Nobody knows why the Ebola virus surfaced here and now in this corner of Uganda.
The last major outbreak was five years ago in Kikwit, Congo.
It killed 245 people. T
his outbreak also struck without warning.
What's so startling about Ebola is the speed with which it moves.
Once a person is infected, it can take anywhere from one to three weeks to develop the first symptoms.
Then, in the vast majority of cases, it kills within 48 hours.
Health workers have been trying frantically to control the epidemic.
The people were told to abandon the tradition of washing the dead and not to shake hands.
People are crowding Gulu's Hospitals, terrified they may be the next victims.
This family waits for news about a nine-year-old daughter.
She is showing all the symptoms.
Doctors believe if they can replace fluids as fast as they are lost, they can sometimes beat Ebola.
But Ebola is still poorly understood, and so whenever there's an outbreak, scientists from around the world come to look for answers.
A team from the Centers for Disease Control has set up a field lab in Gulu.
"Each new outbreak really provides a lot of new information that's gonna be important for towns like Gulu and even for places like Paris, New York or wherever else where people are concerned about how this virus spreads and what they can do to prevent the spread of that virus."
Florence is a nurse who contracted Ebola while treating a patient.
Outside the hospital, her friends keep a vigil hoping that Florence will be one of the survivors.