Infection With The Ebola Virus example essay topic

1. INTRODUCTION A. HISTORY OF VIRUS 1. AFRICA, ZAIRE 2.1970 B. SYMPTOMS AND AFFECTS 1. BLEEDING, HEMORRHAGING 2. DEATH W / IN 20 DAYS C. CURES 1. NONE KNOWN D. INTERNATIONAL EFFORTS 2.

HISTORY OF VIRUS A. WHERE IT STARTED 1. SCIENTISTS B. HOW IT IS SPREAD 1. NON AIRBORNE 2. BODILY CONTACT C. WHERE IT EXISTS TODAY 3. SYMPTOMS AND EFFECTS A. SEVERE FEVER, ABDOMINAL PAIN 1. INSIDES "MELT" B. DEATH RATES AND TOTALS 2 SURVIVORS, BUT EBOLA VIRUS AS THE CAUSE WAS NOT VERIFIED 4.

CURES A. NONE KNOWN CURES, RESEARCH BEING PERFORMED ON MONKEYS. Ebola virus is a relatively recently discovered virus, that when it infects humans, caries with it a 50-90% fatality rate. Symptoms of this deadly virus include Sudden Fever, Weakness, Muscle Pain, Headache, Sore Throat, Vomiting, Diarrhea, Rash. Internal results include Limited Kidney Function, Limited Liver Function, and Internal and External Bleeding. The incubation period for the Ebola virus ranges from 2 to 21 days, depending upon the method of infection. A direct inoculation of the virus into the bloodstream of human will bring about symptoms markedly faster than other forms of less direct contact.

The virus is present in the male's reproductive fluids, and can be transmitted through sexual contact for up to 7 weeks after clinical recovery from the Ebola virus. The Ebola virus can be diagnosed with laboratory testing of blood specimens under maximum containment conditions - because of the high risk of infection to those handling infected blood. There is currently no treatment or vaccination available for the Ebola virus. Transmission of the Ebola virus occurs by direct contact with the bodily fluids of patients infected with the virus.

The handling of chimpanzees that are either ill or have died from the Ebola virus can also transmit the virus. Any suspicion of infection with the Ebola virus should be treated with extreme caution: immediate isolation from other patients and strict barrier nursing techniques must be practiced. All instruments, clothing, or biological matter must be either disposed of or thoroughly disinfected immediately. The initial outbreaks of the Ebola virus occurred in 1976. Springing forth from unknown origins, this virus held the nations of Zaire in fear as it quickly claimed the lives of many of it's citizens.

As this was the first recorded outbreak of the Ebola virus, the medical community was unsure of how to handle Ebola. The level of care in Zaire during this outbreak was very low, and as a result of the many infected victims congregated in public areas, the virus continued to spread among the denizens of Zaire. The intervening years have slowly produced scientific data on the nature of the virus - yet treatment is still unavailable for those infected. The first outbreak, as stated earlier, occurred in Zaire in 1976. This first outbreak was followed by one in western Sudan, also in 1976. In total, these two outbreaks have been traced to the deaths of 340 people - resulting from the 550 plus cases that were identified in these two nations.

After lying dormant for several years the Ebola virus once again made it's presence known in 1979. Once again, no cause was identified as 34 cases of Ebola were identified in Sudan. This occurrence brought the deaths of 22 patients -showing a fatality rate of more than 60%, just as in the 1976 outbreaks. The next instance of humans contracting the Ebola virus occurred in 1995. The Ebola Zaire strain was discovered once again on April 10, 1995 when a patient hospitalized for what was believed to be Malaria infected the surgical team during an operation. Those involved with the operation developed symptoms indicating a viral haemorrhagic fever disease.

This outbreak occurred in the city of Kik wit, Zaire. Although the virus was spreading at a rapid rate, a coordinated effort of international health services was able to contain the outbreak. Present in this coalition of health organizations was the Centers for Disease Control and Prevention (the CDC) and the World Health Organization- aided by members of the medical community from France, Belgium, and several southern African nations. In this most recent epidemic (defined as all cases occurring from 1 July 1995), approximately 233 deaths have been caused, and 293 cases identified as Ebola -bringing the fatality rate to nearly 80% in the outbreak of 1995) Ebola was also detected in the United States in 1989, but this strain of the virus, known as Ebola Reston, is not harmful to the Homo Sapien population. In 1989 a shipment of African Green and Rhesus Monkeys arrived in Reston, Virginia from the Philippines.

These monkeys were infected with the Ebola virus, yet no human cases were documented. 149 workers came into contact with these monkeys in Reston, Virginia and not one became ill - although two did develop antibodies for Ebola Reston. A recent outbreak of the Ebola Virus occurred in November of 1995. There had been a rash of deaths in the population of chimpanzees living within the Tai Forest. On 24 November 1995, a Swiss researcher on the Cote d'Ivore of West Africa contracted the disease from an infected chimpanzee in the Tai Forest. The researcher was rushed to a Swiss hospital where she recovered.

After an autopsy of the chimpanzee indicated that it was showing effects similar to those visible in human patients, a search began for the locale the virus is indigenous to. However, the Tai Forest comprises over 4200 square kilometers, and field researchers were unable to locate the virus. The Ebola virus has not been very research able. Part of the difficulty is that the virus is so communicable, research must be conducted in very strictly controlled settings requiring safeguards and equipment that are beyond the reach of many laboratories. Also, because of the Ebola virus' very lethal tendencies, it is extraordinarily difficult to obtain a specimen for research. The most concentrated research efforts to date have been performed by the World Health Organization and the Centers for Disease Control and Prevention.

Although some understanding of the virus has occurred, much of the information needed to develop a treatment and vaccine still remains elusive to researchers. Research has led to a better understanding of the pattern of symptoms which the Ebola virus causes in humans. Most patients arrive overtly ill, dehydrated, apathetic, and disoriented - further medical investigation quickly shows other symptoms indicating an infection with the Ebola virus. The Ebola virus is best known for the extraordinary amount of bleeding, both internal and external, that it causes init's victims. The death of the patient usually occurs within 7 to 16 days, with the specific cause being shock - often accompanied with severe blood loss.

As early as 10-14 days after infection with either the Marburg or Ebola viruses, an immune response can be detected. The primary response of the immune system is to produce antibodies against the surface glycoproteins. This response is relatively ineffective in that the Ebola still flourishes within the human body and is fatal to most infected persons. There is also little known about the cell-mediated response to these viruses. The pathology of the Ebola virus produces lesions found in liver, spleen, and kidney. They are characterized by focal hepatic necrosis and by follicular necrosis of the lymph nodes and spleen.

As the disease progress into it's later stages, hemorrhage occurs in the gastrointestinal track, pleural, peri cardinal, and peritoneal spaces. Abnormalities in the coagulation occur (blood), suggesting that disseminated coagulation is a terminal event. Research also points out that macrophages and fibroblasts appear to be the initial and also preferred site of replication by Ebola. Experimental treatments have included human interferon, human convalescent plasma and anti coagulation therapy. These treatments, however, have met with mixed results and any success is quite controversial. The only effective preventative measure currently known is to crate a physical barrier of some sort - surgical masks, quarantine wards, et cet era - that is capable of blocking the transmission of the virus to currently uninfected patients.

As stated previously, past research has been significantly slowed as a result of the extreme pathogenicity of the Ebola virus, as well as the Marburg virus. Recombinant DNA technology holds hope in that the molecular structure of the virus is beginning to be understood. This type of research will also lead to an understanding of the way in which this virus replicates itself and the interactions that occur between virus and host. The goal is to gain an understanding of the frequency, ways in which it is transmitted, and also to identify where in nature the Ebola virus naturally resides - to identify it's initial host organism.

Ebola timeline / Overview 1. Viral hemorrhagic fever in southern Sudan and Northern Zaire. Bowen et al., Lancet,' 77, 1: 571-573.2. Management of patients with suspected viral hemorrhagic fever.

CDC-Morbidity and Mortality Weekly Report, Supp. 37/S-3: 1-16, 1988.3. Update: Ebola-related filo virus infection in nonhuman primates and interim guidelines for handling nonhuman primates during transit and quarantine. CDC- MMWR, 39 (2): 22-4, 29-30, 1990 4. Biosafety in Microbiological and Biomedical Laboratories. CDC / NIH, HHS Publication No.

CDC-1993, 3rd Edition. 5. Epidemiologic investigation of Marburg virus disease, Southern Africa, 1975. Conrad, et al., Am. J. Trop. Med. Hyg.

,' 78, 27: 1210-1215.6. Molecular biology and evolution of filo viruses. Feldmann et al., Arch. Virol (supp) 1993; 7: 81-100.7.

Association of Ebola-related Reston virus particles and antigen with tissue lesions of monkeys imported to the United States, Gisbert et al., J. Comp. Path., '92,106: 137-152.8. Preliminary Report: isolation of Ebola virus from monkeys imported to USA, Jahrlinget al., Lancet, '90,335: 502-05.9. Isolation and partial characterization of a new virus causing acute hemorrhagic fever in Zaire. Johnson, et al., Lancet, '77, 1: 569-571.10.

Agent of disease contracted from green monkeys. Kissing et al., '68, Science, , 160,888-890.11. Pathology of Ebola virus infection. Murphy, F.A... in: Ebola Virus Hemorrhagic fever, ed. Patty n, pp 37-42.1978.

Elesvier / North Holland, Amsterdam. 12. Marburg virus morphology and taxonomy. Murphy, F.A. (in same text as above). pp 61-82.13. Marburg virus infection in monkeys. Murphy et al.

Lab. invest., '71, 24: 279-291.14. Filorviruses. Peters CJ et al. in: Emerging Viruses. S. Morse, Ed., pp 159-75. Oxford University Press, New York. 1991.15. Filo viruses as emerging pathogens.

Peters CJ et al. Seminars in Virology, '94, 5: 147-154.16. Sequence analysis of the Ebola virus genome: organization, genetic elements, and comparison with Marburg. Sanchez et al., Virus Res. '93, 29: 215-240.17. Firsthand clinical observations of Ebola hemorrhagic fever in Zaire. Rev. Inf.

Dis., '89, 11: S-790-793.