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WHAT IS EBOLA VIRUS? The genus Ebolavirus is a virological

taxon included in the family Filoviridae, order Mononegavirales. 

The species in this genus are called ebolaviruses. Five species are known, and four of these cause Ebola virus disease in humans.

The name Ebolavirus is derived from the Ebola River in Zaire (now the Democratic Republic of the Congo), where Ebola virus was first discovered.

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- Characteristics of Filoviruses:     - Filamentous form with a uniform diameter of approximately 80 nm but display great variation in length.    - Nonsegmented negative-stranded RNA genome containing 7 structural and regulatory genes.

Group: Group V (-)ssRNA. Order:Mononegavirales

Family:Filoviridae Genus:Ebolavirus

Virus Classification

 First isolated in 1976 in Zaire and Sudan.

 Ebola Hemorrhagic Fever was first found in 1976 It struck two countries within that year a.  Sudan – in a town called N’zara b.  Zaire, now known as the Democratic Republic of Congo   In these two instances the mortality rate was between 50 –90%

Following those epidemics, Ebola hit Africa in many other instances the worst yet being in the year 2000 when it struck Uganda infecting more than 400 people.

Biosafety level 4 agent, as well as a Category A bioterrorism agent

History

Zaire Sudan Côte d'Ivoire Bundibugyo Reston

Subtypes

single linear negative-sense, single-stranded RNA

lipid envelope. destroyed by heat (60°C, 30 min), acidity

Structure

Nonhuman primates

Fruit bats

Reservoir

Person-to-person (secretions) Exposure to bats (Pteropodidae family) Nosocomial transmission Accidental infection of workers in any

Biosafety-Level-4 Use of filoviruses as biological weapons

Transmission

•Virus enters the body via infected blood/body fluid in contact with a mucosal surface or a break in intact skin.

•Virus replicates preferentially in monocytes/macrophages and dendritic cells which facilitate dissemination of the virus throughout the body via lymphatic system.

•Other cells are secondarily infected and there is rapid viral growth in hepatocytes, endothelial and epithelial tissues.

•There is strong cytokine/inflammatory mediator release of TNF-a and inflammatory cascade.

Pathogenesis - how does Ebola cause disease?

•Leads to endothelial damage, increased vascular permeability and shock.

•This results in the end organ damage and multi-organ dysfunction

•Diffuse intravascular coagulopathy(DIC) with platelet and coagulation factor consumption which leads to hemorrhage.

•IgM starts forming in 2 day and IgG in 5-8 days post infection. Immunologic response correlates with survival.

•Thus the observation that those who live >1 week are more likely to survive.

Pathogenesis

Incubation period of 7–10 days (range, 3–16 days  abrupt onset of fever, chills, and general malaise weakness, headache, myalgia, nausea, vomiting,

diarrhea, and abdominal pain relative bradycardia  nonproductive cough and pharyngitis, with the

sensation of a lump or "ball" in the throat  non pruritic maculopapular rash on the upper

body

Signs and symptoms

 reddening of eyes  petechiae, purpura, ecchymoses,

and hematomas (especially around needle injection sites).

impaired blood clotting. bleeding from mucous

membranes (e.g. gastrointestinal tract, nose, vagina and gums) is reported in 40–50% of cases. 

Bleeding phase

Leukopenia , neutropenia, thrombocytopenia

Increased AST and ALT Protienuria

Labaratory findings

DIAGNOSIS

treatment

supportive therapy.

• balancing the patient’s fluids and electrolytes• maintaining their oxygen status and blood

pressure• treating them for any complicating infections• correction of severe coagulopathy

Zmapp -combination of three different monoclonal antibodies

Vaccines in phase 1 trials

wearing of protective clothing (such as masks, gloves, gowns, and goggles)

the use of infection-control measures (such as complete equipment sterilization and routine use of disinfectant)

isolation of Ebola HF patients from contact with unprotected persons.

prevention

Guinea, Sierra Leone, Liberia, and Nigeria

Current outbreak

In March 2014, the World Health Organization (WHO) reported a major Ebola outbreak in Guinea, a western African nation; it is the largest ever documented, and the first recorded in the region. Researchers traced the outbreak to a two-year old child who died on 6 December 2013.

On 8 August 2014, the WHO declared the epidemic to be an international public health emergency.

By 6 September 2014, 4,293 suspected cases including 2,296 deaths had been reported.

Medscape

NEJM – Ebola -A Growing Threat? Heinz Feldmann, M.D. May 7, 2014DOI: 10.1056/NEJMp1405314

CDC

Feldmann H, Geisbert TW. Ebola haemorrhagic fever. Lancet. 2011 Mar 5;377(9768):849-62.

WHO: EBOLA RESPONSE ROADMAP UPDATE

 Isaacson, M; Sureau, P; Courteille, G; Pattyn, SR;. Clinical Aspects of Ebola Virus Disease at the Ngaliema Hospital, Kinshasa, Zaire, 1976. Retrieved 2009-07-08.

Wikipedia

References