Ebola a Threat to Humanity

Momodou Jallow

Biology 101

Ebola a Threat to Humanity

        Ebola is a disease that is currently killing thousands of people in Africa. Just last week I spoke to a Liberian friend of mine in Texas who said that nobody is left in his family. A house that was filled with 12 people is now empty because they are all dead and the future leaders of Africa are suffering from this as well.  Ebola hemorrhagic fever is a severe, often fatal, disease in humans and non-human primates caused by the Ebola virus.  In 2014, a major outbreak of Ebola Virus spread amongst several African countries, including Sierra Leone, Guinea, and Liberia. According to the World Health Organization, The virus first appeared in the Democratic Republic of the Congo (formerly Zaire) in the summer of 1976. Most outbreaks have been small, but the virus and captured the attention of the world due to death rates that can be as high as 90% as well as the visceral manner in which it kills [7,24]. Few viruses have the ability to turn internal organs into a soup that promptly flows out of the body, so those that do tend to capture the public eye. Despite the low incidence of infection, the lethality and potential airborne transmission of Ebola virus makes it a severe biological threat. This is compounded by the possibility of the virus being obtained from the wild for use as a biological weapon, something Japanese terrorist cult Aum Shinrikyo once unsuccessfully attempted. As of the present, there are no licensed vaccines or specific antiviral treatments available for Ebola virus infections, with significant progress only made in the development of vaccines for nonhuman primates. Therefore, the elucidation of the viral replication cycle as well as complete understanding of viral proteins is necessary for the production of human treatments.

        This mysterious hemorrhagic fever was first described in two separate 1976 outbreaks first in southern Sudan and subsequently in northern Zaire, now Democratic Republic of the Congo. A causative agent was isolated from patients in both epidemics and named Ebola virus after a small river in northwestern Zaire. Only years later did researchers recognize that the plagues were caused by two distinct species of Ebola virus, Sudan Ebola virus and Zaire Ebola virus. The third African species, Cote d'Ivoire Ebola virus was isolated in 1994 from an infected ethnologist who had done a necropsy on a chimpanzee from the Tai Forest. Only in 2007 was a fourth African species, Bundibugyo Ebola virus, isolated. An additional viral species, Reston Ebola virus, has origins in the Philippines. It was first discovered in a quarantine facility for Cynomolgus monkeys (Macaca fascicularis) in Reston, VA, USA, and made popular by Richard Preston's best-selling novel The Hot Zone. Luckily for the monkey caretakers, this is the only strain that is non-pathogenic in humans. Recently, Reston Ebola virus has been found infecting pigs in the Philippines. This raises important concerns for public health and food safety in this country, causing some to worry that this could turn into a serious problem for parts of Asia the Ebola virus enters the host primarily through mucosal surfaces or skin abrasions, with most human infections occurring after direct contact with patients or cadavers. In addition, there have been several cases in which hunters are infected after eating contaminated meat found in the forest. Also, most Ebola outbreaks are centered in hospitals in Africa where practices of basic hygiene and sanitation are considered luxuries. However, in modern hospitals with disposable needles and knowledge of basic hygiene and barrier nursing techniques, the virus rarely spreads on a large scale. Airborne transmission between monkeys was demonstrated during the outbreak of Reston Ebola virus in Virginia, but there is limited evidence of airborne transmission in any human epidemics. One of the reasons that Ebola is so dangerous is that its symptoms are varied and appear quickly, yet resemble those of other viruses so much that the hemorrhagic fever is not rapidly diagnosed. Generally, the abrupt onset of symptoms follows an incubation period of 2-21 days and is characterized by high fever, chills and myalgia. Subsequent signs of infection indicate multisystem involvement and include gastrointestinal (nausea, vomiting, diarrhea), respiratory (chest pain, cough) and neurological (headache) manifestations. The unfortunate thing about these symptoms is that they are easily mistaken for malaria, typhoid fever, dysentery, influenza or various bacterial infections, all of which are far more common in regions where Ebola is prevalent, but also less fatal.