On September 30, 2014, a first person was diagnosed with Ebola in the United States. That has awoken the media as the virus had by then become a danger to the western world, even thought there were already more than 3,000 victims in Western Africa from the same outbreak.

When this article was published, the number of victims was still increasing. The Ebola virus is therefore very dangerous because it makes its victims sick very quickly and the fatality rate is very high. There is no cure so far and no approved vaccine. It is important that personnel of all health fields become knowledgeable about this highly contagious virus.

Ebola virusEbola, or Ebola haemorrhagic fever, is a disease caused by an infection from one of the Ebola virus strains. It can infect humans, nonhuman primates, and some other mammals.

Ebola was discovered in 1976, following two different outbreaks, one in Sudan and the other in the Democratic Republic of Congo. Since then there were about 30 different outbreaks, with the 2014 epidemic in West Africa being the largest and the most severe.

Description

Ebola virus entering cellEbola is a filamentous, single-stranded RNA virus with an unusual morphology. The shape of the virus can range from an “L”, “U”, “6”, or anything in between. Depending on the species, it may have different lengths.

There are five Ebola virus species, four of which are known to cause disease in humans:

  • Zaire ebolavirus (ZEBOV), also responsible for the 2014 outbreak in West Africa;
  • Sudan ebolavirus (SUDV);
  • Reston ebolavirus (RESTV) has infected only non-human primates;
  • Taï ebolavirus (TAFV);
  • Bundibugyo ebolavirus (BDBV).

Once it enters the human body, the virus can attack many different cells, including those of the immune system. When infected, those cells lead to programmed cell death, which triggers internal bleeding and weakens the immune system.

Transmission

Fruit batIt is thought that the Ebola virus was introduced to humans through close contact with the blood or other body fluids of infected animals, mostly mammals. It is believed that fruit bats are natural hosts of the virus and they may have been the origin of the 2014 outbreak.

In human-to-human transmission, the virus is spread through direct contact, meaning through broken skin or mucous membranes (for example eyes, nose or mouth) with:

  • blood or body fluids (including but not limited to urine, saliva, sweat, feces, vomit, breast milk, and semen) of a person who is sick with Ebola;
  • objects (like needles and syringes) that have been contaminated with the virus;
  • deceased human bodies from Ebola during funeral preparations.

If a person survives from Ebola, its fluids are not contagious anymore. But transmission from semen can occur up to 2 months after clinical recovery, therefore men are advised not to engage into sexual activity during that period.

Ebola is not spread through the air or by water. It isn’t, in general, transmitted by food either. However, Ebola may be spread as a result of handling wild animals hunted for food.

There is no evidence that mosquitos or other insects can transmit Ebola. Only mammals have shown the ability to become infected and spread the virus.

Symptoms

Symptoms of Ebola may appear anytime from 2 to 21 days (incubation period) after exposure to the virus, but the average is 8 to 10 days. Humans are not contagious until the Ebola symptoms are developed.

Early symptoms are similar to the ones of the flu, and they include:

  • fever;
  • fatigue;
  • muscle pain;
  • headache;
  • sore throat.

Late severe symptoms include:

  • vomiting;
  • diarrhoea;
  • rash;
  • internal and external bleeding (eyes, gums, nose, stools, etc.);
  • secondary bacterial infection may co-occur;
  • symptoms of impaired kidney and liver function may also appear.

When fatal, most people die of hypovolemic shock (decreased blood volume in the body) and multisystem organ failure.

Treatment

Ebola patientAs to the day this article was written, there was no proven treatment available for Ebola. There are however some potential treatments that are being evaluated, such as immune therapies, drug therapies and blood products.

To improve survival of a sick person, supportive care and rehydration are the only available interventions. They include:

  • providing oral or intravenous fluids and balancing electrolytes (body salts);
  • preserving oxygen status and blood pressure;
  • treating secondary bacterial infections if they occur.

Prevention

When this article was published, there was no approved vaccine against Ebola, but 2 potential ones were undergoing safety testing. Currently, the best prevention against the spread of the virus is the application of basic interventions.

To reduce animal-to-human transmission:

  • reduce contact with infected animals and the consumption of their raw meat; their product should be cooked thoroughly before consuming;
  • handle infected animals with gloves and other appropriate protective clothing;

To reduce human-to-human transmission:

  • social mobilisation and education;
  • surveillance of ill people for 21 days and tracing their contacts;
  • reduce direct to close contact with people with Ebola symptoms, particularly with their body fluids;
  • when taking care of ill patients, appropriate protective equipment should be worn;
  • safe burials of infected deceased bodies;
  • good hygiene and maintaining a clean environment.

Ebola and dental care

Ebola and dental careWhen there is an outbreak, dental professionals should not treat patients if they have signs and symptoms of Ebola, and in addition, if they had travelled to a place where the outbreak was occurring within the last 21 days.

When facing a patient like that, the ADA (American Dental Association) advises the following:

  • immediately protect themselves by using standard precautions and physical barriers;
  • calling 911 on behalf of the patient;
  • notify the appropriate health department.

It is recommended to delay routine dental treatments on these patients until 21 days have elapsed.

References

  1. Centers for Disease Control and Prevention (www.cdc.gov).
  2. World Health Organization (www.who.intl).
  3. 19-20 Ebola is a filamentous virus with a single-stranded RNA genome (The Microbial World).
  4. Ebolavirus (Wikipedia).
  5. Ebola ressources for dentists (American Dental Association).
  6. Ebolavirus – Pathogen Safety Data Sheets (Public Health Agency of Canada).
  7. Why Ebola is so dangerous (BBC News Africa).

The information above should be used as a reference only. Any medical decision should not be done before consulting a health care professional.

The masculine gender has been used without prejudice to make reading easier.