During each of these outbreaks, most cases occurred under the challenging conditions of the developing world. These conditions, including a lack of adequate medical supplies and the frequent reuse of needles and syringes, played a major role in the spread of disease. The outbreaks were quickly controlled when appropriate medical supplies and equipment were made available and quarantine procedures were used. After outbreaks of Ebola virus hemorrhagic fever among human populations, investigators tested thousands of specimens from animals captured near the outbreak areas, but their efforts to identify the source of the virus have thus far been unsuccessful. Symptoms of Ebola virus hemorrhagic fever in humans begin 4 to 16 days after infection.
Patients develop fever, chills, headaches, muscle aches, and loss of appetite.
As the disease progresses, vomiting, diarrhea, abdominal pain, sore throat, and chest pain may develop. The blood fails to clot, and patients may bleed from injection sites as well as into the gastrointestinal tract, skin, and internal organs. Similar symptoms are seen in nonhuman primates. A diagnosis is made by detection of Ebola antigens, antibody, or genetic material, or by culture of the virus from blood or tissue samples. Research on the subtypes of Ebolavirus must be done in a special high-containment laboratory to protect scientists working with infected tissues.