Thursday, September 4, 2014

Chapter 1: An Introduction: What is Ebola Virus?

                                                              Electron Micrograph of an Ebola Virus. Photo courtesy of Anna Almendrala, The Huffington Post


According to The Free Dictionary definition of:
Electron Micrograph- (Biology) a photograph or image of a specimen taken using an electron microscope.



                By definition, Ebola virus, formerly known as Ebola hemorrhagic fever, is an infectious and fatal disease that are native in Africa. Ebola occur primarily in Central and West Africa and also near tropical rainforests. Individuals with Ebola virus may suffer organ failure,  severe internal and external bleeding and, in such many cases, death. Ebola virus is transmitted to human from wild animals and is spread through the transmission of human to human contact. Experts indicated that fruit bats of the Pteropodidae family is the reservoirs of the Ebola virus.



                                                                                

1. The History

                 Ebola was first identified in Sudan and the Democratic Republic of the Congo in 1976. However, the natural reservoir for Ebola virus was still unknown. 

  •  In 1976, Ebola was first identified in Sudan and Zaire, infecting 284 people.
  • Few months later, 318 people was infected in Yambuku, Zaire.
  •  In 2012, 77 cases were reported and with a total of 36 deaths in the Democratic Republic of the Congo. In Uganda, 7 cases with Ebola and 4 deaths.
  • In 2014, the largest outbreaks ever, which occur in West Africa (Guinea, Liberia, Nigeria, and Sierra Leone). 

 

                                    Map of Ebola outbreaks in Africa from 1979-2008. Photo courtesy of Zach Orecchio University of South Florida Geography Dep.



       Table: Chronology of previous Ebola virus disease outbreaks




YearCountryEbolavirus speciesCasesDeathsCase fatality
2012Democratic Republic of CongoBundibugyo 572951%
2012UgandaSudan7457%
2012UgandaSudan241771%
2011UgandaSudan11100%
2008Democratic Republic of CongoZaire321444%
2007UgandaBundibugyo1493725%
2007Democratic Republic of CongoZaire26418771%
2005CongoZaire121083%
2004SudanSudan17741%
2003 (Nov-Dec)CongoZaire352983%
2003 (Jan-Apr)CongoZaire14312890%
2001-2002CongoZaire594475%
2001-2002GabonZaire655382%
2000UgandaSudan42522453%
1996South Africa (ex-Gabon)Zaire11100%
1996 (Jul-Dec)GabonZaire604575%
1996 (Jan-Apr)GabonZaire312168%
1995Democratic Republic of CongoZaire31525481%
1994Cote d'IvoireTaï Forest 100%
1994GabonZaire523160%
1979SudanSudan342265%
1977Democratic Republic of CongoZaire11100%
1976SudanSudan28415153%
1976Democratic Republic of CongoZaire31828088%


   Table of Ebola virus Outbreaks in Africa. Photo courtesy of WHO: World Health Organization.




2. Virology
                                                  
Virus Classification

Group: Group V ((-) ssRNA)
Order: Mononegavirales
Family: Filoviridae
Genus: Ebolavirus
Type Species: Ebola virus

3. 3 Genera of Filoviridae
  •    Cuevavirus
  •    Marburgvirus
  •    Ebolavirus 

4. 5 Identified Subspecies of Ebola virus 
  •  Ebola virus (or Zaire ebola virus)
  •  Sudan ebolavirus
  •  Tai Forest ebolavirus (formerly as Cote o'lovire)
  •  Bundibugyo ebolavirus
  •  Reston ebolavirus

            4 of the 5 have caused disease in humans, whereas, Reston ebolavirus has caused disease in nonhuman primates. Bundibugyo ebolavirus, Zaire ebolavirus, and Sudan ebolavirus have been associated with the large outbreaks in Africa, in addition, Zaire ebolavirus is responsible for the 2014 West African outbreak.





Reference:
http://www.who.int/mediacentre/factsheets/fs103/en/
http://en.wikipedia.org/wiki/Ebola_virus_disease#mediaviewer/File:EbolaSubmit2.png