Discovering the World of Viral Hemorrhagic Fevers By
Discovering the World of Viral Hemorrhagic Fevers By Christy Leaman
Topic Overview • Definitions & Descriptions: • Hosts – Infectious Diseases – Viral Hemorrhagic Fevers • Examples • Transmission Subject Basics Scary Examples • Symptoms & Treatment • Implications for Humans 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 Quiz Yourself Learn More
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 Quiz Yourself Learn More
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 Quiz Yourself Learn More
Some examples of VHFs: • • • Dengue Lassa Virus Yellow Fever Marburg Ebola Do you want to see the most deadly of all VHFs? No, I’m scared! Subject Basics Scary Examples Spread of VHFs Yes, show me! Impact on Humans Quiz Yourself Learn More
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 rate Subject Basics Scary Examples Spread of VHFs Ebola outbreak 2007, Democratic Republic of the Congo Impact on Humans Quiz Yourself Learn More
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 Quiz Yourself Learn More
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 Quiz Yourself Learn More
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 Quiz Yourself Learn More
Symptoms & Treatment Symptoms Include: • Treatment: • Marked fever • Fatigue • Muscle aches • Dizziness • Exhaustion • Weakness • In many cases, there is no effective drug treatment or vaccination available • Supportive therapy may be the only option 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 Quiz Yourself Learn More
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 Quiz Yourself Learn More
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 Quiz Yourself Learn More
Check your understanding! v A VHF is a type of Correct! Infectious Disease: Sorry! A VHF IS a special True False v Are humans likely to be a host of a VHF? Yes Subject Basics No Scary Examples type of Infectious Disease. Sorry! Humans become sick by these viruses; a host can carry the virus without being destroyed by it. Spread of VHFs Impact on Humans Quiz Yourself Learn More
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-feverviruses. html • Dengue Hemorrhagic Fever [Web Photo]. Retrieved from http: //research. fuseink. com/pa 5 xgkmo 7 kz 7 rm/difference-between-malaria-and-deguefever Subject Basics Scary Examples Spread of VHFs Impact on Humans Quiz Yourself Learn More
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