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

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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

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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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