Signs and symptoms

EVD, which has a case fatality rate of up to 90%, is a severe acute viral illness often characterized by the sudden onset of fever, intense weakness, muscle pain, headache, nausea and sore throat. This is followed by vomiting, diarrhoea, impaired kidney and liver function, and in some cases, both internal and external bleeding. Laboratory findings frequently include low white blood cell and platelet counts and elevated liver enzymes.

The incubation period, the time interval from infection with the virus to onset of symptoms, is 2 to 21 days. People remain infectious as long as their blood and secretions contain the virus, a period that has been reported to be as long as 61 days after onset of illness.

Diagnosis and treatment

When considering the diagnosis of EVD, other, more common diseases should not be overlooked; for example, malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.

Definitive diagnosis of EVD is made through laboratory testing. Because samples from patients are a source of infection risk for others, testing is conducted under maximum biological containment conditions.

No vaccine is available, nor is there any specific treatment. Severely ill patients require intensive supportive care. Patients are frequently dehydrated and require oral rehydration with solutions containing electrolytes, or intravenous fluids.

Preventative measures

Raising awareness of the risk factors for infection and the protective measures that should be taken is the only way to reduce human infection and subsequent deaths. Close unprotected physical contact with Ebola patients should be avoided. Appropriate use of gloves and personal protective equipment (including hand hygiene before putting on, and especially after taking off personal protective equipment) should be practised when taking care of ill patients at home. Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home.

Almost all transmission of the virus to health-care workers has been reported when basic infection control measures have not been observed. Health-care workers caring for any patient should practice standard precautions. When caring for patients with suspected or confirmed Ebola virus infection, health-care workers should apply, in addition to standard precautions, other infection control measures to avoid any exposure to patients’ blood and body fluids and with possibly contaminated environments.

Preparation for burial of the bodies of persons who have died from Ebola virus disease also carries high risks of transmission of the virus. Those who have died from the disease should be promptly and safely buried.