The Ebola Virus. By Emilio Saavedra

Transcription

1 The Ebola Virus By Emilio Saavedra Etiological Agents: Ebolavirus is the etiologic agent. [1] There are four main families of viruses that are agents of Ebola (hemorrhagic fever). [1] These four families are filoviruses, bunyaviruses, arenaviruses and flaviviruses. [1] The agents that are the most well- known include Ebola virus, dengue virus and Margburg virus. [1] Transmission: The first infection of a person with Ebola is usually from a spillover event where that person comes in contact with an animal infected with the Ebola virus. [2] Transmission of the Ebola virus from person to person is through direct contact with an infected person, or direct contact with bodily fluids of an infected person. [2] The bodily fluids may include blood, sweat, semen, breastmilk, mucous, urine, saliva vomit etc. [2] Men who have recovered from Ebola can infect their sexual partners with their semen. [2] Reservoirs: Some mammals are believed to be reservoirs for the Ebola virus. [3] These animals include bats, rodents and monkeys. [3] Bats are considered to be the most likely reservoir of the Ebola virus. [3] General Characteristics of MO (specific): Ebola virus belongs to the family Filoviridae in the order Mononegavirales. [4] Filoviruses are non- segmented, enveloped negative- stranded RNA viruses. [4] They have varying morphology. Ebola virus particles vary in length, but have a diameter of 80nm. [4] The genome consists of seven genes in the order 3 leader, nucleoprotein, virion protein 35, VP40, glycoprotein, VP30, VP24, RNA- dependent RNA polymerase (L)- 5 trailer. [4] Key Tests for identification: The tests that can be done to identify Ebola are, antibody- capture enzyme- linked immunosorbent assay (ELISA), antigen- capture detection tests, serum neutralization test, reverse transcriptase polymerase chain reaction (RT- PCR) assay, electron microscopy and virus isolation by cell culture. [5]

2 Signs and Symptoms of disease: The Ebola virus incubation period is 2 to 21 days. [5] Humans become infectious when they develop symptoms. [5] The first symptoms include a sudden onset of fatigue, muscle pain, fever, headache and sore throat. [5] These symptoms are followed by diarrhea, vomiting, rash, symptoms of impaired liver and kidney function, and possibly internal and external bleeding. [5] Laboratory findings may include elevated liver enzymes and low platelet and white blood cell counts. [5] Historical Information: The first known Ebola virus outbreak was in 1976 in Sudan and the Democratic Republic of the Congo (DRC). [6] The next known outbreak occurred in [6] Since then, Ebola outbreaks have been occurring more frequently. [6] There is currently an outbreak occurring in West Africa and it is the largest known Ebola outbreak to date. [6] The countries affected by this current outbreak are Guinea, Sierra Leone and Liberia. [6] There was a small outbreak in August of 2014 in the Democratic Republic of Congo. [6] There were also three smaller outbreaks in [6] These outbreaks were in the Democratic Republic of Congo and Uganda. [6] Two of the three outbreaks that year were in Uganda. [6] Virulence Factors: It is largely unknown what the virulence factors of filoviruses are and their exact functions. [7] The virulence factors are currently under investigation. [7] Filoviruses can infect and alter a variety of cells, sometimes killing them. [7] Filoviruses infect the liver, the immune system and the adrenal gland. [7] Hemorrhagic fever results, causing blood clots to form in the circulatory system, which may lead to multi- organ failure, blood vessel weakening and becoming permeable, which can cause bleeding and swelling, and altering of the immune system. [7] The altered immune cells release massive amounts of inflammatory molecules. [7] These molecules can increase the permeability of blood vessels. [7] This may cause the some cells to apoptose and send the body into shock. [7] Control/Treatment: To date, there is no FDA- approved vaccine or medicine available for Ebola. [8] Some treatments can increase the chance of an infected person s chance of survival. [8] These treatments include providing intraveinous

3 fluids and balancing electrolytes, maintaining oxygen status and blood pressure, and treating other infections if they occur. [8] There are measures that can be taken to control the spread of Ebola. [9] Practice careful hygiene. [9] Avoid contact with bodily fluids. [9] Wash hands with soap and water or alcohol- based hand sanitizer. [9] Do not handle items that have come in contact with the bodily fluids of an infected person. [9] Do not handle the body of a person who has died of Ebola. [9] Avoid contact with infected fruit bats or primates, or semen of a man who has had Ebola. [9] Prevention/Vaccine info: Prevention recommendations include meticulous attention to personal protective equipment and environmental cleaning during patient care. [10] There are no FDA- approved vaccines to protect against EVD in humans. [10] There are clinical trials being done for vaccine candidates. [10] These are ChAd3- ZEBOV, rvsv- ZEBOV, Ad26- EBOV and MVA- EBOV. [10] Local Cases or Outbreaks (with incidence figures): On September 30 th, 2014, a man in a Dallas, Texas hospital became the first person in the United States was diagnosed with Ebola. [11] On October 12 th, a second person, a health care worker who had cared for the patient tested positive for Ebola. [11] October 15 th, 2014 a second health care worker tested positive for Ebola. [11] The health care worker had also cared for the original patient. [11] The Ebola outbreak in Texas appears to have ended, however more than 200 travelers have been monitored for symptoms in Texas. [11] Global Cases or Outbreaks (with incidence figures): As of March 20, 2015, there have been 26,757 cases of Ebola (suspected, probable and confirmed) worldwide. [12] There have been 14,954 laboratory- confirmed cases worldwide. There have been 11,079 total deaths worldwide. [12] References: 1. Viral Hemorrhagic Fever (Ebola). 7 Nov Washington State Guidelines for Notifiable and Surveillance. 5 May Guideline- Ebola.pdf#nameddest=casedef

4 2. Transmission. 24 April Center for Disease Control and Prevention. 5 May About Ebola Virus Disease. 24 April Center for Disease Control and Prevention. 5 May Feldmann, Heinz, and Thomas W Geisbert. Ebola Haemorrhagic Fever. Lancet (2011): PMC. Web. 5 May Ebola Virus Disease. WHO. April World Health Organization. 8 May Ebola Overview: History, Origins and Transmission. 29 January Public Health of England. 8 May origins- reservoirs- transmission- and- guidelines/ebola- origins- reservoirs- transmission- guidelines 7. Ebola Fact Sheet Federation of American Scientists. 8 May Ebola Virus Disease Association for Professionals in Infection Control and Epidemiology. 11 May Practice/Practice- Resources/Ebola- virus- disease#/ Prevention. 24 April Center for Disease Control and Prevention. 5 May

5 10. Ebola Vaccines, Therapies and Diagnostics. WHO. April World Health Organization. 8 May Ebola in Texas. Texas Department of State Health Services. 11 May Ebola Outbreak in West Africa- Case Counts. 10 May Center for Disease Control and Prevention. 11 May west- africa/case- counts.html