Deadly Diseases That Affect Our World

1
Deadly Diseases That Affect Our World

• Prion Diseases
• Hemorrhagic Fever Virus
• HIV

• What are they?
• How do they spread?
• How do they effect us?

Bridget Sorrell Bryant Bullard Charles Prior
2
Prion Diseases

• Are transmissible from host to host of a single
  species and sometimes even from one species to
  another (such as a laboratory animal)
• Destroy brain tissue giving it a spongy
  appearance
• For these reasons prion diseases are also called
  transmissible spongiform encephalopathies or TSEs
• Before the victim dies of a TSE, the damage to
  the brain is reflected in such signs as loss of
  coordination and - in humans - dementia.

3
What is the infectious agent in TSEs?

• One suggestion is that the disease is caused by
  an infectious agent such as a virus.
• But viruses have a genome and - despite intense
  efforts - no evidence of a virus has ever been
  found in these brain extracts.
• To date, the evidence indicates that the
  infectious agent in the TSEs is a protein.

4
Types of diseases and how they are transmitted

• Scrapie
• Bovine Spongiform Encephalopathy (BSE) or Mad
  Cow Disease
• Kuru
• Gerstmann-Sträussler-Scheinker disease (GSS)
• Fatal Familial Insomnia (FFI)
• Creutzfeldt-Jakob Disease (CJD)

5
Hemorrhagic Fever Viruses

• Some of the deadliest viruses in the world.

• Include Several Families of Viruses
• Flavivirus Yellow Fever
• Arenavirus Puumala
• Bunyavirus Guanarito
• Filovirus Ebola

6
Virus Transmission

• Carried by host animals which come into contact
  with humans.
• Monkeys
• Mice
• Mosquitoes

• Transmitted through human error.
• Unsterilized syringes in missionary hospitals
• Infected bodily fluids spread to those helping
  dead or dying.

7
Virus Transmission
8
Effects on Humans

• Hemorrhagic Fever causes patience's to bleed to
  death from the inside out.

• Example Ebola
• Destroys host cells directly.
• Attacks vital organs especially the liver.
• Decreases number of platelets in blood, reducing
  its ability to clot.
• Modify blood vessels in such a way that the
  remaining platelets stick to them causing them to
  rupture.

9
HIV The Immune System

• HIV replicates rapidly and destroys many cells of
  immune system each day
• Attack of HIV is met by a vigorous defense and
  blocks HIV from multiplying out of control
• Balance of power eventually shifts to HIV and
  eventually causes AIDS

10
(No Transcript)
11
Evolutionary Theory of HIV in the Body

• On average, each time it replicates its RNA into
  DNA it differs from the previous generation
• HIV has a very high replication rate increasing
  its chances of evolving a mutation that is
  useful to the virus
• After 10 years, the viral particles are several
  thousand generations beyond the original particle

12
Treatment Options

• Those with weak immune systems control the virus
  better
• Vaccines are possible to boost immune system
  against one particular epitope
• Chemical agents should be applied early on in
  treatment

13
Conclusions

• Currently these diseases have no known cure,
  tough to detect, and treatment research is
  ongoing.