Clinical picture and diagnosis
The incubation period of Ebola disease is 2 to 21 days (typically: 6 to 10 days).[10]
The first phase of the disease (1-3 days) is characterised by non-specific symptoms such as fever, malaise, fatigue and myalgia. Laboratory results may show leukopenia, thrombocytopenia and elevated liver enzymes. During the second phase (day 3-10), gastrointestinal symptoms will develop such as anorexia, sore throat, dysphagia, nausea, vomiting and diarrhoea. Fluid losses may be significant. Other symptoms include a fairly typical conjunctival injection, headache, abdominal pain, arthralgias and chest pain. Approximately 20% of patients will now develop a maculopapular rash involving mainly the face and torso.[11] Haemorrhagic symptoms occur in less than half of affected patients. Usually bleeding starts from the gums followed by the formation of petechiae. Severe gastrointestinal blood loss may also be present.[12] Laboratory results may show persistently elevated liver enzymes, elevated creatinine as well as electrolyte disorders. Furthermore, thrombocytopenia and an elevated PT/PTT/D-dimer may be seen consistent with disseminated intravascular coagulation. Secondary complications include bacterial superinfections, kidney injury and respiratory failure which may in part be caused by aggressive fluid resuscitation. This phase may result in death during the second week of illness as a consequence of multiorgan failure caused by hypovolaemic and/or distributive shock. Survivors typically begin to improve during the second week of illness. The convalescent period can persist for more than two years and includes a ‘post-Ebola syndrome’ which involves musculoskeletal symptoms, fatigue, headache, neurocognitive abnormalities, uveitis, tinnitus and hearing loss.[13] Interestingly, Ebola has been shown to persist in some body fluids even after clearance of the virus from the blood. A cohort study of male survivors during the West African epidemic showed that Ebola virus can persist in semen for up to 19 months following acute infection.

Diagnostic tests for Ebola include detection of specific RNA sequences by RT-PCR in the blood or detection of viral antigens by immunoassays.[14] RT-PCR results may be available in approximately 2 to 6 hours but are not commonly available in most settings where epidemics have occurred. Diagnostic testing should be carried out in a biosafety level 4 laboratory when available. A false-negative result may occur early in the disease course (<72 hours) and this may warrant repeat testing in symptomatic patients who initially test negative depending of pretest likelihood of infection. Rapid immunoassays detecting Ebola antigens were developed during the West African epidemic and are useful when RT-PCR is not available.[15] These tests are not recommended for the testing of asymptomatic patients.

Treatment and prevention
Treatment and prevention of Ebola has made great strides forward since the last major epidemic (2014-2016) although mortality remains high, especially when treatment is started relatively late as is usually the case in Africa. An overview of the current treatment and prevention options of Ebola disease can be found in table 1. Treatment of Ebola disease can be divided in supportive care and antiviral therapies. Supportive care primarily aims to maintain or restore normal physiology and includes fluid and electrolyte replacement, mechanical ventilation or oxygen therapy, blood products, analgesics, antiemetic drugs, renal replacement therapy and antimicrobial therapy in case of a bacterial superinfection. Antiviral therapies include the use of antibodies (Inmazeb, ZMapp and Ansuvimab) against the Zaire species of Ebola and other investigational therapies. Importantly, the recent PALM trial conducted during the Ebola epidemic in North Kivu (DRC, 2018 to 2019) investigated the efficacy of Inmazeb, Ansuvimab, remdesivir and ZMapp.[16] ZMapp, a combination of monoclonal antibodies directed against viral surface glycoproteins, was considered the control group as an earlier randomised controlled trial found a reduction of mortality in the ZMapp group compared with the placebo group (PREVAIL II trial).[17] The PALM trial was stopped early because an interim analysis of a subgroup of 499 patients with a low initial viral load showed a significantly greater survival among patients who received Inmazeb or Ansuvimab compared with ZMapp or remdesivir. Overall mortality at 28 days in the Ansuvimab group was 35.1% versus 49.7% in the ZMapp group (p=0.007). Mortality in the Inmazeb group was 33.5% compared with 51.3% in a ZMapp subgroup enrolled during the same study period (p=0.002). Importantly, earlier treatment was associated with improved survival which had not been shown previously. Unfortunately, other investigational therapies such as convalescent plasma did not show a survival benefit.[18]. Favipiravir, a prodrug which after metabolisation inhibits viral RNA-dependent RNA polymerase, may improve survival. The efficacy, however, should be further investigated.[19]

Prevention consists of infection control measures, outbreak management and vaccines. It is recommended to follow the infection prevention and control recommendations from the World Health Organisation. This includes hand hygiene, contact/droplet precautions, environmental cleaning/disinfection and personal protective equipment. Personal protective equipment should include double gloves, boot covers, a liquid impermeable gown, a hood that covers the head and neck, full face shield and FFP2 mask.