I. Definition of Ebola Virus a. Ebola was first discovered in 1976 near the Ebola River in what is now the Democratic Republic of the Congo 1 b. Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans. 2 c. Ebola viruses are found in several African countries. d. Spread as a result of handling bush meat (wild animals hunted for food) and contact with infected bats. 1 e. Most human infections result from direct contact with infected people or animals1 f. Can lead to serious illness or death. g. Ebola is not spread through the air, by water, or in general, by food.
II. Agent a. Only a few species of mammals (e. g. , humans, bats, monkeys, and apes) have shown the ability to become infected with and spread Ebola virus. b. through contact with an infected animal, such as a fruit bat or primate (apes and monkeys), which is called a spillover event. 1 c. Person-to-person transmission follows and can lead to large numbers of affected people. d. Symptoms may appear anywhere from 2 to 21 days after exposure to Ebola, but the average is 8 to 10 days. 1 e. The virus family Filoviridae includes 3 genera: Cuevavirus, Marburgvirus, and Ebolavirus.
(2) f. There are 5 species that have been identified: Zaire, Bundibugyo, Sudan, Reston and Tai Forest. The first 3, Bundibugyo ebolavirus, Zaire ebolavirus, and Sudan ebolavirus have been associated with large outbreaks in Africa. The virus causing the 2014 west African outbreak belongs to the Zaire species. (2) III. Condition a. Symptoms 1 b. Fever c. Severe headache d. Muscle pain e. Weakness f. Fatigue g. Diarrhea h. Vomiting i. Abdominal (stomach) pain j. Unexplained hemorrhage (bleeding or bruising) IV. Morbidity/Mortality a. The average EVD case fatality rate is around 50%.
Case fatality rates have varied from 25% to 90% in past outbreaks. 2 b. Once people recover from Ebola, they can no longer spread the virus to people in the community. c. It can be difficult to distinguish EVD from other infectious diseases such as malaria, typhoid fever and meningitis. (2) V. Disease Distribution A. Host characteristics 1. Age/Sex/Ethnicity a. Because the natural reservoir host of Ebola viruses has not yet been identified, the way in which the virus first appears in a human at the start of an outbreak is unknown. B. Environmental Attributes 1.
Geographic Areas a. Ebola virus has officially moved beyond the continent of Africa. b. Two imported cases, including one death, and two locally acquired cases in healthcare workers have been reported in the United States, and one confirmed case has been reported in Spain.. 1 2. Social and Economic Factors a. Because the Ebola virus is prevalent in developing countries the affected population are very poor but the virus does not discriminate. b. It would seem that most of the upper-middle class exposure is to health care workers caring for the sick. 3. Occupation a.
Healthcare providers caring for Ebola patients and family and friends in close contact with Ebola patients are at the highest risk of getting sick because they may come in contact with infected blood or body fluids. b. Health-care workers should always take standard precautions when caring for patients, regardless of their presumed diagnosis. These include basic hand hygiene, respiratory hygiene, use of personal protective equipment (to block splashes or other contact with infected materials), safe injection practices and safe burial practices. (2) C. Temporal Variation 1. Seasonal a.
The most severely affected countries, Guinea, Sierra Leone and Liberia have very weak health systems, lacking human and infrastructural resources, having only recently emerged from long periods of conflict and instability. On August 8, the WHO Director-General declared this outbreak a Public Health Emergency of International Concern. b. There seems to be no seasonal correlation. VI. Current Hypotheses a. The 2014 Ebola epidemic is the largest in history and is affecting multiple countries in West Africa. b. Once people recover from Ebola, they can no longer spread the virus to people in the community. VII. Principal Gaps in Knowledge a.
It is thought that fruit bats of the Pteropodidae family are natural Ebola virus hosts. Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals such as chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest. 2 b. There is currently no FDA approved vaccine but there are two potential vaccines that should be available in 2015. VIII. Areas for Further Epidemiologic Research a. Beacause there is not a FDA approved vaccine for the Ebola virus there is great potential for epidemiologic research. b.
The direct cause of Ebola virus is unknown. IX. Appraisal of data a. As the number of Ebola cases increase research on the Ebola virus will receive more attention and funding.
References 1. Cdc. gov. Ebola Hemorrhagic Fever | CDC. 2014.Available at: http://www. cdc. gov/vhf/ebola/. Accessed November 10, 2014. 2. Who. int. WHO | Ebola virus disease – website. 2014. Available at: http://www. who. int/csr/disease/ebola/en/. Accessed November 10, 2014. 3. Peters C, LeDuc J. An Introduction to Ebola: The Virus and the Disease. The Journal of Infectious Diseases. 1999;179(s1):Six-xvi. doi:10. 1086/514322. 4. New England Journal of Medicine.
NEJM — Ebola Outbreak. 2014. Available at: http://www. nejm. org/page/ebola-outbreak. Accessed November 10, 2014. 5. Swoger B. Scholarly articles and other sources about the Ebola outbreak | Information Culture, Scientific American Blog Network. Blogsscientificamericancom. 2014. Available at: http://blogs. scientificamerican. com/information-culture/2014/09/29/scholarly-sources-and-reliable-news-sources-about-the-ebola-outbreak/. Accessed November 10, 2014. 6. Sullivan N, Yang Z, Nabel G. Ebola Virus Pathogenesis: Implications for Vaccines and Therapies. Journal of Virology. 2003;77(18):9733-9737. doi:10. 1128/jvi.
77. 18. 9733-9737. 2003. 7. Chowell G, Nishiura H. Transmission dynamics and control of Ebola virus disease (EVD): a review. BMC Medicine. 2014;12(1):196. doi:10. 1186/s12916-014-0196-0. 8. Bausch D, Schwarz L. Outbreak of Ebola Virus Disease in Guinea: Where Ecology Meets Economy. PLoS Neglected Tropical Diseases. 2014;8(7):e3056. doi:10. 1371/journal. pntd. 0003056. 9. Sis. nlm. nih. gov. Ebola Outbreak 2014: Information Resources. 2014. Available at: http://sis. nlm. nih. gov/dimrc/ebola_2014. html. Accessed November 10, 2014. 10. Nadakavukaren A. Our Global Environment. Long Grove, Ill. : Waveland Press; 2011.