Transcript History - BEHESHTI MAAL

IN THE NAME OF GOD
Ebola virus and Dengue Fever
By:Rozita Yousefian
HISTORY
Filovirus epidemics have originated from Africa and apparently from a single source in the
Philippines.
• 1976: First recognized when two unrelated epidemics occurred in northern Zaire and southern
Sudan, with subsequent outbreaks in Sudan, Zaire, Ivory Coast, Gabon, Uganda, DRC, and South
Africa
• 1989-1991: Another Ebola subtype in Reston, Virginia, among dying cynomolgus monkeys,
o1992 in Italy
o1996 in the US .
• Classified among the highest priority for bioterrorism agents.
What is ebula?

Ebola HF is a severe, often-fatal disease in humans and nonhuman
primates

The virus is one of two members of a family of RNA viruses called the
Filoviridae

There are five identified subtypes of Ebola virus. Four of the five have
caused disease in humans: Ebola-Zaire, Ebola-Sudan, Ebola-Ivory
Coast and Ebola-Bundibugyo. The fifth, Ebola-Reston, has caused
disease in nonhuman primates, but not in humans.
Disease Agent Characteristics:

Family: Filoviridae; Genus: Ebolavirus
Virion morphology and size: Enveloped, helical, crossstriated nucleocapsid, filamentous or pleomorphic virions that are
flexible with extensive branching80 nm in diameter and 970-1200
nm in length


Nucleic acid: Linear, negative-sense, single-strandedRNA, ~18,900
kb in length

Physicochemical properties: Stable at room temperature and can
resist desiccation; inactivated at 60°C for30 minutes; infectivity
greatly reduced or destroyed by UV light and gamma irradiation,
lipid solvents
The crystal structure of ebolavirus GP
The three GP1 subunits(colored blue and
green), mediate attachment to new host cells,
and are tethered together by the three GP2
subunits (white). GP2 forms the protein
machinery which drives fusion of the viral
membrane with the host cell. The human
antibody KZ52 (yellow) binds an epitope at
the base of the GP chalice where it bridges
GP1 to GP2.
Ebola Virus Replication
Infection, spread and target cell destruction by Ebola virus
How is it spread?

researchers have hypothesized that the first patient becomes
infected through contact with an infected animal.

direct contact with the blood and/or secretions of an infected
person

contact with objects, such as needles, that have been
contaminated with infected secretions.
Symptoms and Signs

The incubation period for Ebola HF ranges from 2 to 21 days
The onset of illness is abrupt and is characterized by;
Fever headache muscle aches sore throat


Weekness followed by diarrhea, vomiting, and stomach pain.

After 5 days rash, red eyes, hiccups and internal and external
bleeding may be seen in some patients.
Laboratory diagnosed of ebula




Virus culture
antigen detection
IgG and IgM antibody serology and electron
microscopy
ELISA and PCR
treatment

There is no standard treatment for Ebola HF.

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.
Vaccine




DNA vaccine
VLP-based ebola virus
VSV-based ebola virus
DNA prime boost adenovirus vaccine
prevention

wearing of protective clothing, such as masks, gloves and goggles

isolation of Ebola HF patients from contact with unprotected
persons.

Using properly disinfected equipment and educating health care
worker.

If a patient with Ebola HF dies, it is important that direct contact
with the body of the dead person be prevented.
What is

mosquito-borne disease and viral illness

caused by infection with 1 of 4 types of the dengue virus.

When a person recovers from dengue infection they develop a
long-term (not always lifetime) immunity to that type, but not the
other 3 types.

If the person is infected again with a different virus type, they may
develop the more severe form of the illness known as DHF.
World Distribution of Dengue 2008
Atlantic
Ocean
Pacific
ocean
Dengue Risk Areas
No Known Dengue Risk
Indian
Ocean
How is it spread?

by the bite of an infected dengue mosquito (usually the
Aedes aegypti species).

There is no spread from human to human
Symptomes of dung fever
Sympotomes of DHF

It commonly seen in children under 15 years but can also
occur in adults.

It begins with the same symptoms as dengue fever but is
followed by rapid deterioration, bleeding and cardiovascular
collapse 2-5 days later.

The duration of DHF depends on the severity of the illness
and response to treatment. It can be fatal.
Laboratory diagnostic



RT-PCR
serologic diagnosis by testing for IgM antibodies to
dengue with an IgM antibody-capture enzyme-linked
immunosorbent assay (MAC-ELISA).
……..
Treatment?

There is no specific treatment or vaccine.

Aspirin and non-steroidal anti-inflammatory drugs should not
be used as they can affect blood clotting

DHF require hospitalization with intensive monitoring and
treatment.
How to avoid getting dengue fever

1) Improve environmental monitoring

2) Support better health surveillance

3) Improve mosquito control

4) Reduce global warming pollution to decrease the extent and severity of
warming

5) Provide information for travelers visiting high-risk dengue areas
Refrences
Jason S. Richardson.et all,Recent advances in ebola virus vaccine development,Human vaccines6:6 439-449,2010
Ebola Hemorrhagic Fever Information Packet , Division of High-Consequence Pathogens and Pathology National
Center for Emerging Zoonotic Infectious
Diseases Centers for Disease Control and Prevention U.S. Department of Health and Human Services,1-12 2009
Apendix 2, TRANSFUSION,49-2009
Kim Knowlton,et all, Mosquito-Borne Dengue Fever
Threat Spreading in the Americas, Natural Resources Defense Council,2009
Dengue fever,center of Disease Control,2010