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Ebola

Overview

Ebola Virus Disease (EVD), formerly known as Ebola Haemorrhagic Fever, is a severe Filoviridae viral infection that is often fatal. The virus is transmitted to humans from wild animals and then spreads through communities through human-to-human transmission. The first outbreak of EVD occurred in remote villages of central Africa located near tropical rainforests. The most recent outbreak in 2014 occurred in West Africa, involving major urban areas in addition to remote rural areas. The average fatality rate is around 50%. Currently, there is no specific viral treatment but supportive care with rehydration and symptomatic treatment improves the chance of survival.

 

Signs and symptoms

Signs and symptoms typically present abruptly within 5-10 days of infection.

Early signs and symptoms include:

  • Fever

  • Severe headache

  • Joint and muscle aches

  • Chills

  • Weakness

 

Later symptoms which develop over time include:

  • Nausea and vomiting

  • Diarrhoea which may contain blood

  • Red eyes

  • Raised rash

  • Chest pain and cough

  • Stomach pain

  • Severe weight loss

  • Bleeding, usually from the eyes but can occur from other                                                                                                        orifices

  • Bruising

  • Internal bleeding

 

Complications:

As the illness progresses, complications can arise such as:

- Multiple organ failure

- Severe bleeding

- Jaundice

- Delirium

- Seizures

- Coma

- Shock

 

 

Recovery is slow for surviving individuals. It can take months to regain weight and strength, as the viruses remains in the body for weeks. During recovery individuals may experience:

  • Hair loss

  • Sensory changes

  • Hepatitis

  • Weakness

  • Fatigue

  • Headaches

  • Ocular inflammation

  • Testicular inflammation

 

Causes

Fruit bats of the Pteropodidae family are believed to be natural Ebola hosts. The virus can then be introduced into the human population through close contact with the blood, secretions, organs, or other bodily fluids of infected animals. Infection by chimpanzees, gorillas, monkeys, fruit bats, forest antelope and porcupines have been reported. Filoviruses are stable and highly infective. Ebola then spreads human-to-human via the direct contact through broken skin or mucous membranes with the bodily fluids of individuals infected with the Filovirus. Transmission can also occur with surfaces and materials such as bedding or clothing which have been contaminated with infected bodily fluids.

 

Risk factors / at risk groups

The most severely affected countries, Guinea, Liberia and Sierra Leone, have very weak health systems. They also lack human and infrastructural resources and have only recently emerged from long periods of conflict and instability. As a result, healthcare provision remains basic.

There is increased risk of Ebola in individuals who have:

  • Travelled to Africa areas where an outbreak has occurred

  • Conducted animal research using monkeys imported from Africa or the Philippines

  • Provided medical or personal care to an infected person (family members or healthcare professionals)

  • Prepared bodies for burial as they remain contagious

 

Diagnosis / microbiology testing

  • Maculopapular rash indicative of a filoviral infection

  • Contact with infected individual / travel to an area of outbreak

  • Virus detected in enzyme-linked immunosorbent assay (ELISA)

  • Also identified using reverse transcriptase polymerase                                                                                                             chain reaction (PCR)

 

Treatment

There is no recommended antiviral treatment for Ebola at present. Early supportive care is provided including rehydration therapy, replacing lost blood, maintaining blood pressure and treating other secondary infections which may develop. Oxygen replacement therapy is also provided if required.

 

Vaccines / preventative measures

There is currently no licensed Ebola vaccine but 2 potential candidates are currently being evaluated.

Preventative measures include:

  • Avoiding areas of known outbreaks

  • Avoiding consumption of bush meat sold in local markets

  • Avoid contact with infected individuals, particularly in the later stages of the disease where contagion is highest

  • Avoiding contact with infected bodily fluids

  • Following protective control methods such as wearing protective clothing (gloves, masks, gowns, eye shields), disposing of used needles and sterilising instruments

  • Avoiding handling remains. Specially trained teams should bury individuals as the bodies remain contagious after death

 

Outbreak control relies on several interventions; case management, surveillance, contact tracing, efficient laboratory services, safe burials and social mobilisation.

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