Ebola Virus Disease

Ebola Virus Disease

What is ebola virus ? 

Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever. It was discovered in 1976 when two consecutive outbreaks of fatal hemorrhagic fever occurred in different parts of Central Africa. The first outbreak occurred in the Democratic Republic of Congo (formerly Zaire) in a village near the Ebola River, which gave the virus its name.

Electron micrograph of Ebola virus.

 The second outbreak occurred in what is now South Sudan, approximately 850 km away. The Ebola outbreak in West Africa is the world’s deadliest to date and the World Health Organization has declared an international health emergency as more than 3,850 people have died of the virus in Guinea, Liberia, Sierra Leone, and Nigeria this year.

There are five subspecies of the Ebola virus: Zaire ebolavirus (EBOV), Bundibugyo ebolavirus (BDBV), Sudan ebolavirus (SUDV), Taï Forest ebolavirus (TAFV) and Reston ebolavirus (RESTV)  and four of them can make people sick.

After entering the body, it kills cells, making some of them explode. It wrecks the immune system, causes heavy bleeding inside the body, and damages almost every organ. 

Transmission :

Ebola is extremely infectious but not extremely contagious. Ebola is considered moderately contagious because the virus is not transmitted through the air. 

It can be spread by

  • Humans can be infected by other humans if they come in contact with body fluids(saliva, mucous, vomit, feces, sweat, tears, breast milk, urine, and semen) from an infected person or contaminated objects from infected persons(like blood, feces, vomit) from a person sick with Ebola or the body of a person who died from Ebola. 
  • Humans can also be exposed to the virus, for example, by butchering infected animals.
  • Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD. This occurs through close contact with patients when infection control precautions are not strictly practiced.
  • Burial ceremonies that involve direct contact with the body of the deceased can also contribute to the transmission of Ebola.
  • Having sex with an infected person without using a condom – studies show traces of Ebola may remain in semen many months after recovery
  • Pregnant women who get acute Ebola and recover from the disease may still carry the virus in breastmilk, or in pregnancy-related fluids and tissues. This poses a risk of transmission to the baby they carry, and to others. 
  • If a breastfeeding woman who is recovering from Ebola wishes to continue breastfeeding, she should be supported to do so. Her breast milk needs to be tested for Ebola before she can start.
  • Women who become pregnant after surviving Ebola disease are not at risk of carrying the virus.

Symptoms :

symptoms appear eight to 10 days after exposure to the virus, but the incubation period can span two to 21 days. Ebola usually begins with a sudden onset of fever, weakness, muscle pain, headache, and sore throat. 

This is often followed by 

  • Weakness and fatigue
  • Red eyes,
  • Skin rash
  • Vomiting
  • Diarrhea

Ebola virus is a rare and deadly disease. Recovery from EVD depends on good supportive clinical care and the patient’s immune response.

Diagnosis : 

To determine whether EVD is a possible diagnosis, there must be a combination of symptoms suggestive of EVD and possible exposure to EVD within 21 days before the onset of symptoms. According to WHO Confirmation that symptoms are caused by Ebola virus infection are made using the following diagnostic methods:

  • antibody-capture enzyme-linked immunosorbent assay (ELISA)
  • antigen-capture detection tests
  • serum neutralization test
  • reverse transcriptase-polymerase chain reaction (RT-PCR) assay
  • electron microscopy
  • virus isolation by cell culture.

If a person shows signs of EVD and has had a possible exposure, he or she should be isolated (separated from other people) and public health authorities notified. Blood samples from the patient should be collected and tested to confirm infection. Ebola virus can be detected in blood after onset of symptoms. It may take up to three days after symptoms start for the virus to reach detectable levels.

Current WHO recommended tests include:

  • Automated or semi-automated nucleic acid tests (NAT) for routine diagnostic management.
  • Rapid antigen detection tests for use in remote settings where NATs are not readily available. These tests are recommended for screening purposes as part of surveillance activities, however reactive tests should be confirmed with NATs.

The preferred specimens for diagnosis include:

  • Whole blood collected in ethylenediaminetetraacetic acid (EDTA) from live patients exhibiting symptoms.
  • Oral fluid specimens stored in universal transport medium collected from deceased patients or when blood collection is not possible.

Samples collected from patients are an extreme biohazard risk; laboratory testing on non-inactivated samples should be conducted under maximum biological containment conditions. All biological specimens should be packaged using the triple packaging system when transported nationally and internationally.

Treatment :

The Ebola virus does not have a cure or vaccine at this time or we can say there is currently no licensed vaccine available for Ebola.

At the moment, treatment for Ebola is limited to intensive supportive care and includes :

  • Offering oxygen therapy to maintain oxygen status
  • Treating a patient for any complicating infections
  • providing intravenous and/or oral fluids to prevent dehydration
  • Using medication to support blood pressure, reduce vomiting and diarrhea and to manage fever and pain.

Vaccine for Ebola : 

There is no approved medicine or vaccine to treat or prevent Ebola. Scientists have tested some drugs on animals, which seemed to work.

In October 2014, the World Health Organization (WHO) organized an expert consultation to assess, test, and eventually license two promising Ebola vaccines:

  • cAd3-ZEBOV – GlaxoSmithKline has developed this vaccine in collaboration with the United States National Institute of Allergy and Infectious Diseases (NIH). It uses a chimpanzee-derived adenovirus vector with an Ebola virus gene inserted.
  • rVSV-ZEBOV – this was developed by the Public Health Agency of Canada in Winnipeg with NewLink Genetics, a company, located in Ames, IA. The vaccine uses a weakened virus found in livestock; one of its genes has been replaced by an Ebola virus gene.

Prevention :

There are a number of ways to protect yourself and prevent the spread of EVD :

  • Non-disposable protective equipment must be properly disinfected before reuse.
  • Ensuring all healthcare workers wear protective clothing
  • Care and isolation of patients, to prevent further spread and save lives
  • The WHO also warns against consuming raw bushmeat and any contact with infected bats or monkeys and apes. Fruit bats in particular are considered a delicacy in the area of Guinea where the outbreak started.
  • The bodies of those that have died of Ebola virus infection remain highly infectious and should be promptly and safely buried.
  • Contact tracing, to find and test anyone who had recent contact with a new Ebola patient.
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