Ebola Virus Disease

• Ebola is a disease of humans and other primates caused by ebola viruses, which is a severe, often fatal illness in humans.
• The average EVD case fatality rate is around 50%. Case fatality rates have varied from 25% to 90% in past outbreaks.
• EVD first appeared in 1976 in 2 simultaneous outbreaks, one in Sudan and the other in DRC (near the Ebola River which gave its name).

• It has also spread between countries starting in Guinea to Sierra Leone, Senegal and Liberia (by land) and to Nigeria (by air).
• The most severely affected countries were Guinea, Sierra Leone and Liberia due to their very weak health systems.
• Year 1976 marked the first outbreak of Ebola (Sudan) which infected over 284 people with MR of 53%, few months later, second outbreak (Zaire) infected 318 with MR of 88%.

• In 1989, the third outbreak (Reston) was identified in Monkeys, no single infected person developed VHF.
• In 1994, the fourth strain of (Cote d’Ivoire).
• The March, 2014 Ebola outbreak is the largest and most complex Ebola outbreak in history and the first in West Africa.
• On August 8 2014, the WHO Director- General declared this outbreak a Public health Emergency of International Concern.
• WHO identified gorillas and chimpanzees as “natural hosts”, however, experts identify them as mere “accidental hosts” because a large number of them are killed by the virus.
• Further research shows that fruit bats are reservoirs of Ebola virus

• Order: Mononegavirales
• Family: Filoviridae
• Genus: Ebola like viruses
• Species: Ebola
• Subtypes
• Ebola-Zaire, Ebola- Sudan, Ebola-Ivory Coast disease in humans
• Ebola-Reston disease in nonhuman primates

• Virus present in high quantity in blood, body fluids, and excreta of symptomatic EVD-infected patients
• Opportunities for human-human transmission
• Direct contact (blood, fluid or meat of an infected animal or person)
• Indirect contact
• Sharps injury
• Exposure to corpse of person who died of EVD
• Note: semen can test positive after clinical clearance for up to three months (CDC, 2015)
• Incubation period: Patients with EVD typically have an abrupt onset of symptoms 6 to 12 days after exposure (range 2 to 21 days).

• Direct infection of tissues
• Immune dysregulation
• Disseminated intravascular coagulation (DIC) and coagulopathy
• Hypovolemia and vascular collapse
• Electrolytes abnormalities
• Multi-organ failure, septic shock
• Death

Acute onset— typically 6-12 days after exposure (range 2-21 days)

Signs and symptoms

• Initial: fever, chills, myalgia, malaise, anorexia
• After 5 days: GI symptoms
• Later: haemorrhage (not common, hence, EVD and not EHF)
• Others: Headache, conjunctivitis, hiccups, rash, chest pain, shortness of breath, confusion, seizures.

• RT-PCR sample collection
• Volume: minimum volume of 4mL of whole blood in an EDTA plastic bottles
• Sample testing
• RT-PCR to diagnose acute infection (for identification of specific viral genetic fragments) Gold standard.
• Virus isolation
• Immunohistochemical staining and histopathology
• Serologic testing for IgM and IgG antibodies (ELISA)
• Laboratory findings
• Thrombocytopenia (50,000-100,000/mL range)
• Leukopenia followed by neutrophilia
• Transaminase elevation: AST>ALT
• Electrolyte abnormalities from fluid shifts
• Coagulation: PT and PTT prolonged
• Renal: proteinuria, increased creatinine
• Differential diagnosis: Malaria, typhoid fever, meningococcemia, Lassa fever, Acute surgical abdomen, Crimean-Congo hemoharrgic fever, Marburg HF, and some bacterial infections

• Supportive care
• Fluid and electrolyte replacement
• Respiratory support
• Antimicrobial therapy
• Symptomatic care
• Fever (avoid NSAID)
• Correction of severe coagulopathy
• Renal replacement therapy
• Ebola-specific: Immazeb and Ansuvimab

Primary

• Avoidance of unnecessary travel, direct and indirect contacts, attending burials and bush meats consumption.
• Health promotion
• A large number of health workers should be trained; in infection control measures, setting up an epidemiological surveillance network and promoting public health messages.
• Appropriate use of PPE
• Vaccination (rVSV-ZEBOV and Ad26.ZEBOV vaccines)

Secondary

• Health care personnels should have high index of suspicion, be able to identify cases, follow up with and trace cases and their contacts.
• Health facilities should be well equipped both with human and material resources to provide optimum care and treatment.
• Setting up of treatment centres and transit units close to affected villages.

Tertiary

• Ebola creates fear inside communities, and sick people are often stigmatized. Psychological support is provided to patients and their families.
• The health workers should organize participatory health promotion activities with healed patients.

Initial assessment for Ebola Virus Disease

• The risk of exposure to Ebola virus helps us to guide the evaluation and monitoring of both symptomatic and asymptomatic individuals.
• Patients are risk of EBV if they had an exposure that occurred within 21 days before the onset of symptoms.
• However, the level of exposure risk range from high to low to no known identifiable risk. For health care workers, the level of exposure risk can vary depending upon the intensity of the epidemic at their work site.

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