Ebola Virus Disease (EVD)

The five characterized Ebola species are:

Zaire Ebola virus

It has the highest case-fatality rate of the Ebola viruses, up to 90%.

The first outbreak occurred on 26 August 1976 in Yambuku.

The first recorded case was Mabalo Lokela, a 44‑year-old school teacher.

Sudan Ebola virus  

Like the Zaire virus, Sudan Ebola virus emerged in 1976.It was at first assumed to be identical with the Zaire species.

Côte d’Ivoire Ebola virus

Also referred to as Taï Forest Ebola virus, it was first discovered among chimpanzees from the Taï Forest in Côte d’Ivoire, Africa, in 1994.

Bundibugyo Ebola virus

Ebola virus was first confirmed in Bundibugyo District on 24 November 2007.

In 2012, there was an outbreak of Bundibugyo Ebola virus in a northeastern province of the Democratic Republic of the Congo.

Reston Ebola virus  

Reston virus, is thought to be not disease causing for humans.

It was discovered during an outbreak of simian hemorrhagic fever virus (SHFV) in crab-eating macaques from Hazleton Laboratories (now Covance) in 1989.

Transmission

• Ebola virus is transmitted to a human via contact with an infected animal host.
• Human-to-human transmission occurs via direct contact with blood or bodily fluids from an infected person.
• By contact with contaminated medical equipment such as needles.
• Because bodies of the deceased are still infectious, measures have to be taken, to properly dispose of dead bodies in a safe manner despite local traditional burial rituals.

Signs and symptoms

• The incubation period is about 2-12 days, but can be as long as 25 days.
• Ebola Virus Disease begins with a sudden onset of an influenza-like stage characterized by general malaise, fever with chills, arthralgia and myalgia, and chest pain.
• Nausea is accompanied by abdominal pain, anorexia, diarrhea, and vomiting.
• Respiratory tract involvement is characterized by pharyngitis with sore throat, cough, dyspnea, and hiccups.
• The central nervous system is affected as judged by the development of severe headaches, agitation, confusion, fatigue, depression, seizures, and sometimes coma.
• Cutaneous presentation may include: maculopapular rash, petechiae, purpura, ecchymoses, and hematomas (especially around needle injection sites).
• Bleeding from mucous membranes and puncture sites is reported in 40–50% of cases. Sources of bleeds include hematemesis, hemoptysis, melena, and bleeding from mucous membranes of nose, vagina and gingiva.
• Development of hemorrhagic symptoms is generally indicative of a negative prognosis.
• Death occurs due to fluid redistribution, hypotension, disseminated intravascular coagulation, and focal tissue necroses.

Risk factors

• Bats are considered the most likely reservoir. Bats have also been implicated in Marburg virus infections.
• Ebola virus has been detected in the carcasses of gorillas and

Diagnosis

• Medical history and clinical signs
• Blood or serum for Ebola antigen
• RT-PCR (reverse transcription polymerase chain reaction) 

Treatment

• There is currently no approved Ebola virus-specific therapy for EVD.
• Treatment is primarily supportive in nature and includes:
• Strict isolation to prevent spread of infection
• Minimizing invasive procedures
• Balancing fluids and electrolytes to counter dehydration
• Administration of anticoagulants early in infection to prevent or control disseminated intravascular coagulation
• Administration of procoagulants late in infection to control hemorrhaging
• Maintaining oxygen levels
• Pain management
• Administration of antibiotics or antimycotics to treat secondary infections.

Prognosis

• Prognosis is generally poor (average case-fatality rate of all outbreaks to date = 68%).
• If a patient survives, recovery may be prompt and complete.
• Some Ebola viruses are known to be able to persist in the sperm of some survivors, which could give rise to secondary infections and disease via sexual intercourse.

Prevention

• Ebola viruses are highly infectious as well as contagious.

The bodily fluids from diarrhea, vomiting, and bleeding should strictly be disinfected.

• Stop all needle-sharing or use without adequate sterilization
• Sterilization of all used instruments.
• No visitors should be allowed in isolated areas.
• Strict quarantine of all suspected people (no movement is allowed).
• In endemic zones the avoidance of risk factors, such as contact with nonhuman primates or bats, is highly recommended.
• During outbreaks avoid direct (skin-to-skin) contact with patients, their excretions and body fluids, or possibly contaminated materials and utensils.
• Patients should be isolated and medical staff should be trained and apply strict barrier nursing techniques (disposable face mask, gloves, goggles, and a gown at all times).
• Traditional burial rituals, especially those requiring embalming of bodies, should be discouraged or modified, ideally with the help of local traditional healers.
• Laboratory researchers have to be properly trained and wear proper personal protective equipment.
• Avoid sexual intercourse