discovering the world of viral hemorrhagic fevers by christy leaman
TRANSCRIPT
Discovering the World of
Viral Hemorrhagic Fevers
By Christy Leaman
Topic Overview
• Definitions & Descriptions:– Infectious Diseases– Viral Hemorrhagic Fevers
• Examples
• Transmission
• Hosts
• Symptoms &
Treatment
• Implications
for Humans
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
Quiz Yourself
Learn More
Learning Objectives:
• Describe the relationship between Infectious Diseases and Viral Hemorrhagic Fevers
• Determine whether a human can be a host of a Viral Hemorrhagic Fever
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
Quiz Yourself
Learn More
Infections Diseases:
Diseases resulting from organisms
like bacteria, viruses, fungi, or parasites
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Viral Hemorrhagic Fevers
• A type of infectious disease that inhibits clotting of the blood
• Involves extreme damage to multiple bodily systems– In particular, it inhibits the vascular
system and the body’s ability to regulate itself
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Characteristics of VHFs
• RNA viruses• Very few have a cure or successful
drug treatment available • Survive primarily off a host
– An organism that can carry the virus without being destroyed by it
• Human outbreaks are unpredictable and sporadic
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Some examples of VHFs:
• Dengue• Lassa Virus• Yellow Fever• Marburg• Ebola
Do you want to see the most deadly of all VHFs?
Yes, show me!No, I’m scared!
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Level 4 Hot Agents• Some VHFs are so
deadly, they must be handled by a Special Pathogens Branch (SPB)
• The SPB works with Biosafety level-4 pathogens or “hot agents”– Marburg and Ebola viruses
have highest mortality rateEbola outbreak 2007,
Democratic Republic of the
Congo
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Transmission• Host-Human: a host or contaminated object or
substance comes into contact with a human• Host-Livestock-Human: virus is spread to humans
during the slaughter or consumption of meat products
• Human-Human: humans transfer the virus to other humans through contact with person or bodily fluids
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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What are the hosts of VHFs?
• VHFs are zoonotic: the virus resides in an animal or arthropod– These are usually rodents, ticks, or
mosquitoes– The hosts of viruses such as Ebola and
Marburg remain unknown
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Where Do These Diseases Occur?
• The virus and resulting disease generally stay in the host’s region
• Increased travel brings a danger of mass disease spread– Marburg appeared in Germany – Ebola spread from Gabon to South Africa– Ebola Reston, a strain of Ebola which never infected
humans, was found in monkeys in Reston, Virginia in 1990
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Symptoms & Treatment
• Marked fever• Dizziness• Weakness
• Fatigue• Muscle aches• Exhaustion
• Treatment:
• In many cases, there is no effective drug treatment or vaccination available
• Supportive therapy may be the only option
Symptoms Include:
In severe cases:• Bleeding under the skin, in
the internal organs, and from orifices such as the nose, eyes, and mouth
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Prevention and Control
According to the CDC, prevention
should involve:1)Avoiding contact with potential hosts
2) Stop further transmission when a case occurs:
-control rodent populations
-use repellant, bed nets, and proper clothing
-avoid contact with the sick
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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How can scientists work to eliminate this threat?
• Development of vaccine, containment, and treatment strategies• Development of diagnostic tools• Understand VHF transmission and
effects• Appreciate hosts and environmental
ecology for prevention efforts
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Check your understanding!
A VHF is a type of Infectious Disease:
True False
Are humans likely to be a host of a VHF?
Yes No
Correct!
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Sorry! A VHF IS a special type of Infectious Disease.Sorry! Humans become sick by these viruses; a host can carry the virus without being destroyed by it.
Sources• U.S. Center for Disease Control, (2013). Viral hemorrhagic fevers. Retrieved from
website: http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/Fact_Sheets/Viral_Hemorrhagic_Fevers_Fact_Sheet.pdf
• World Health Organization, (2013). Viral hemorrhagic fevers. Retrieved from website: http://www.who.int/topics/haemorrhagic_fevers_viral/en/
• World Health Organization. (2007, September ). Ebola Haemorrhagic Fever in the Democratic Republic of the Congo [Web Video]. Retrieved from http://www.who.int/csr/disease/ebola/en/index.html
• Mark. (Photographer). Infectious Disease News [Web Photo]. Retrieved from http://medicineworld.org/cancer/lead/2-2007/better-control-of-hemorrhagic-fever-viruses.html
• Dengue Hemorrhagic Fever [Web Photo]. Retrieved from http://research.fuseink.com/pa5xgkmo7kz7rm/difference-between-malaria-and-degue-fever
Subject Basics
Scary Examples
Spread of VHFs
Impact on Humans
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Disclaimer
This project is for educational use only.
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