Ebola Trabalho

Ebola Nightmare of the past, terror of the present Bárbara Castro nº 12147 Brigite Ferreira nº17073 Mafalda Queiroz nº18505 Maria João Marques nº13626

Abstract: Ebola virus (EBOV) is a public health concern in Africa and a potential biological weapon. It is transmitted by direct contact with infected body fluids and by animals. The incubation period can be between 2-21days. Once the virus is inside a host, it begins to replicate. The seven proteins that made up the virus begin to consume the host cell as it replicates. These proteins attack the cells structure and structural proteins of the body host cells. The early stage of illness symptoms are like high fever, severe headache, muscle joint or abdominal pain, severe weakness, sore throat, nausea and dizziness occur. Then there are serious symptoms such as diarrhea, dark or bloody feces, vomiting blood, red eyes, petechia, maculopopular rash and purpura. Other symptoms include hypotension, hypovolemia, tachycardia, organ damage (kidney, liver and spleen). As it has no cure the patient usually dies. Resumo: O virus do Ébola é uma preocupação de saúde publica em África assim como uma potencial arma biológica. É transmitido pelo contacto directo com fliudos corporais e através de animais. O perido de incubação é de dois a vinte e dias. Uma vez no hospedeiro, começa a replicar. As sete proteínas presentes no virus consomem as células do hospedeiro, enquanto este replica. Estas proteínas atacam e destroem a estrutura proteica e celular do hospedeiro. Numa fase inicial da doença, ocorrem sintomas como, febres altas, graves cefeleias, dores nos musculos e articulações, dores na garganta, fraqueza, nauseas e tonturas. A segunda fase da doença tem sintomas como fezes negras e ensanguentadas, vomito com sangue, olhos avermelhos, petequias, manchas vermelhas e roxas na pele. Outros simtomas incluem, hipovolémia, taquicardias e falência de orgão vitais como rins e figado. Como não tem cura, o paciente geralmente morre. Introduction: The Ebolavirus belongs to the family Filoviridae that consists of two genera, Marburgvirus and Ebolavirus, which have likely evolved from the same ancestor. The genus Ebolavirus is comprised of five species, Zaire, Sudan, Reston, Côte d’Ivoire (Ivory Coast) and Bundibugyo Ebolavirus which have, with the exception of Reston and Côte d’Ivoire Ebolaviruses, been associated with large hemorrhagic fever (HF) outbreaks in Africa with high case fatality (53–90%). Along with Marburgvirus, it is classified as biosafety level four virus. First identified outbreak occurred in 1976 in Zaire and the last was registered in 2007 inside Kikyo Health Center located in Rwenzori Mountains of Uganda. The reservoirs can be: rodent or fruit bats and monkeys are not proved as reservoirs because they die with early infection. Humans are accidentally infected, but can be a rich source of infection by direct contact with body fluids such as blood.

The virus has tropism for cells of macrophage system, dendritic cells, interstitial fibroblasts and endothelial cells. The presentation of this disease includes a huge variety of symptoms as, high fever, headache, muscle and stomach pain, fatigue, diarrhea, sore throat, hiccups, rash, red eyes, vomiting blood, bloody diarrhea, chest pain, shock, blindness, bleeding and death. In what matter to incubation period it can go from two up to twenty one days.

Virus Definition: The Ebola virus can be defined as a single-stranded virus that has 472 nucleotides from the 3' end and 731 nucleotides from the 5' end that are sufficient for replication. The genomic material by itself is not infectious, but the existence of viral proteins makes the virus infectious. The ways of transmission it is by the attachment to host receptors though the GP (glycoprotein) surface and is endocytosed into vesicles in the host cell and then fusion of virus membrane with the vesicle membrane occurs. The encapsidated, negative-sense genomic ssRNA is used as a template for the synthesis (3' - 5') of polyadenylated, monocistronic mRNAs. Translation of the mRNA into viral proteins happens by using the host cell's machinery, and then post-translational processing of proteins is performed. As viral protein levels rise, a switch turns on from translation to replication. The newly-formed nucleocapsides and envelope proteins associate to the host cells plasma membrane. Clinical manifestation: In the early stage, there may be high fever, severe headache, muscle joint or abdominal pain, severe weakness, sore throat, nausea and dizziness. Before a breakout is notified, these symptoms can be easily mistaken from other disease like malaria, typhoid fever or other bacterial infection, which are less fatal. Then there are serious symptoms such as diarrhea, dark or bloody feces, vomiting blood, red eyes, petechia, maculopopular rash and purpura. Other symptoms include hypotension, hypovolemia, tachycardia, organ damage (kidney, liver, spleen). Chemical reaction between the virus and platetes would lead to interior bleeding. Sometimes, internal or external hemorrhage from orifices (ex. Nose and mouth) may also occur, or incompletely healed injuries. Ebola virus can infect platelets, disrupting clotting. The fatal rate is very high. It's between 50%-90%. Diagnostic methods: Nowadays Ebola virus can be diagnosed by laboratorial methods like, antigen-capture enzyme-linked immune sorbent assay (ELISA) testing, IgM ELISA, polymerase chain reaction (PCR) and virus isolation can be used to

diagnose a ca se of Ebola HF within a few d ays of the onset of symptoms. Persons tested later in the course of the disease or after recovery can be tested for IgM and IgG antibodies; the disease can also be diagnosed retrospectively in deceased patients by using immunehistochemistry testing, virus isolation, or PCR. Treatment: There is no standard treatment for Ebola. Currently, patients receive supportive therapy. This consists of balancing the patient’s fluids and electrolytes, maintaining their oxygen status and blood pressure, and treating them for any complicating infections.

Prevention: Because the identity and location of the natural reservoir of Ebola virus is unknown, prevention presents many challenges but there are few established primary prevention measures. If cases of the disease do appear, current social and economic conditions often favor the spread of an epidemic within health-care facilities. Therefore, health-c are providers must be able to recognize a case of Ebola should one appear. They must also have the ability to perform diagnostic tests and be ready to employ practical viral hemorrhagic fever isolation precautions, or barrier nursing techniques. These techniques include the wearing of protective clothing, such as masks, gloves, gowns, and goggles; the use of infection-control measures, including complete equipment sterilization; and the isolation of Ebola virus patients from contact with unprotected persons. The aim of all of these techniques is to avoid any contacts with the blood or secretions of any patient. If a patient with Ebola virus dies, it is equally important that direct contact with the body of the deceased patient be prevented. World Health Organization and CDC have developed a manual in which is described how to recognize cases of viral hemorrhagic fever, such as Ebola virus, and prevent further nosocomial transmission by using locally available materials and few financial resources. Similarly, a practical diagnostic test that uses tiny samples from patient’s skin has been developed to retrospectively diagnose Ebola virus in suspected casepatients who have died. Bibliography: Jonathan S. Towner, et al, Newly Discovered Ebola Virus Associated with

Hemorrhagic Fever Outbreak in Uganda, November 21, 2008, volume 4, Issue 11, PLoS Pathogens, www.plospathogens.org CMAJ, 6 maio 2008, página 178 Kortepeter M.G., et al, Managing Potential Laboratory Exposure to Ebola Virus by using a patient biocontainment care unit, Emerging

Infectious Diseases, www.cdc.gov/eid, vol.14, No. 6, June 2008, pages 881 – 887 Halfmann, P., et al, Generation of biologically contained Ebola viruses,www.pnas.org/cdi/doi, 28-01-2008, vol. 105, no.4, pp 1129 – 1133 Weekly epidemiological record, 07- 03- 2008, 83º ano, no. 10, pp 8996, www.who.int/wer Dr.T.V.Rao MD, EBOLA and MARBURG, Viral Infections, ppt presentation

Anexo 1 Year

Ebola Species

Country

Zaire

No. of Human Cases

318

Percentage of Deaths Among Cases

88%

1976

E - Zaire

1976

ESudan

Sudan

284

53%

1976

ESudan

Englan d

1

0%

1 979

ESudan

Sudan

34

65%

1 989

EReston

USA

0

0%

1 990

EReston

USA

0

0%

1 992

EReston

Italy

0

0%

Situation

Occurred in Yambuku and surrounding area. Disease was spread by close personal contact and by use of contaminated needles and syringes in hospitals /clinics. This was the first recognition of the disease. Occurred in Nzara, Maridi and the surrounding area. Disease was spread mainly through close contact within hospitals. Many medical care personnel were infected. Laboratory infection by accidental stick of contaminated needle. Occurred in Nzara. Recurrent outbreak at the sam e site as the 1976 Sudan epidemic. Ebola-Reston was introduced into quarantine facilities in Virginia, Texas and Pennsylvania by monkeys imported from the Philippines. Four humans developed antibodies to Ebola-Reston but did not become ill. Ebola was introduced once again into quarantine facilities in Virginia, and Texas by monkeys imported from the Philippines. Four humans developed antibodies but did not get sick. Ebola-Reston was introduced into quarantine facilities in Sienna by monkeys imported from the same export facility in the Philippines that was involved in the episodes in the United States. No hum ans were

1 994

E- Zaire

Gabon

44

63%

1 994

E-Ivory Coast

Ivory Coast

1

0%

1 995

E- Zaire

Zaire

315

81%

1 996

E- Zaire

Gabon

37

57%

infected. Occurred in Minkebe, Makokou and gold-mining camps deep in the rain forest. Initially thought to be yellow Fever; identified as Ebola hemorrhagic fever in 1995. Scientist became ill after conducting an autopsy on a wild chimpanzee in the Tai Forest. The patient was treated in Switzerland Occurred in Kikwit, Democratic Republic o f Congo. Traced to index case-patient who worked in forest adjoining the city. Epidemic spread through families and hospitals. The outbreak impacted not only Kikwit but also surrounding communities. Occurred in Mayibout area. A chimpanzee found dead in the forest was eaten by people hunting for food. Nineteen people who were involved in the butchery of the animal became ill, other cases occurred in family members.