Disease and Epidemiology. What is Disease? . Any condition that jeopardizes the survival of an organism in a particular environment. What is epidemiology?. The study of the causes, distribution, and control of disease in populations. . Some Characteristics of Disease.
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What is epidemiology?
The study of the causes, distribution, and control of disease in populations.
Prions (Mad Cow Disease)Infectious Agents -pathogen – an infectious disease causing agent
Chain of infection
Direct person to person contact- contaminated hands most common
coming in contact with contaminated equipment, food, insect bite
Results in susceptible host, or a person likely to get an infection or disease
Chain of infection can be broken at any point
*Investigator must work backwards to try and determine
the index case
*The mode of transmission/vector
*The “waves” of infection
Virulence – ability of a pathogen to overcome the body’s defense & produce a disease
Host – any organism serving as a residence for a pathogen
Vector – agent/entity that delivers a pathogen to a host, intermittent hostInfectious Disease Causing Agents
1. Two Domains:
Archaebacteria – live in extreme conditions
Eubacteria – all other bacteria
No membrane bound organelles such as a nucleus or mitochondria
4. ________________ How big are bacteria?
5. Where do they live?
Archaebacteria - live in extreme harsh environments – hot temperatures, extreme salinity for example and include halophiles, methanogens, thermophiles, sulfophilic strains
Eubacteria - bacteria we encounter on a daily basis – E. coli for example
Spherical - cocci
Helical or Spiral
Rod - bacillus
Vibrio– comma shaped
8. Have Cell Walls
9. Form Endospores in Harsh Conditions
1. Anthrax - respiratory infection initially presents with cold or flu-like symptoms for several days, followed by severe (and often fatal) respiratory collapse
3. Typhoid fever - caused by the bacteriumSalmonella Typhi. Common worldwide, it is transmitted by ingestion of food or water contaminated with feces from an infected person.
Two Types of Virusesa. Lytic (virulent)b. Lysogenic (temporal) – “dormant”http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter17/animation_quiz_2.htmlhttp://www.cfoxscience.com/mrfox/apbio/Lectures/lysogenic_pathway.swf
--Causes disease immediately
Infectious Diseases:Viral Infection
Infectious Diseases:Viral Infection
Lysogenic Cycle of aTemperate Virus
Activated to produce new viruses
Remains in cell
Dr. Stephen O'Brien's work with HIV led to a discovery that could one day help scientists treat or prevent HIV infection: People from some European populations carry a genetic mutation that prevents HIV from entering their white blood cells. O'Brien hypothesizes that this mutation, dating back 700 years, may have been a selective advantage during the bubonic plague, as it is today, with the onslaught of HIV. From Evolution: "Evolutionary Arms
What are all living things made of?
-- don’t have complete cell parts
What do all living things need?
-- need energy from host cell
How does environment affect living things?
-- do not respond to a stimulus
How do living things reproduce?
-- need host cell to replicate
Symptoms include nasal discharge, obstruction of nasal breathing, swelling of the sinus membranes, sneezing, sore throat, cough, and headache.
Symptoms induced can include mosaic, mottling, necrosis, stunting, leaf curling, and yellowing of plant tissues.
Acquired immunodeficiency syndrome, is caused by the human immunodeficiency virus, or HIV.
HIV destroys the body's ability to fight infections by attacking cells of the immune system.
The vast majority of cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals like raccoons, skunks, bats, and foxes.
Infects the central nervous system, causing encephalopathy and ultimately death.
(Herpes simplex )
Between 50 - 80% of all people possess this virus and is spread through direct contact with an infected individual.
Once the virus has entered the body, it cannot be removed.
Only 10% of HSV1 infected people ever develop a sore.
An acute infection caused by a activation of the varicella zoster virus, which also causes chicken pox.
It usually occurs during adulthood after exposure to chicken pox in childhood. The chicken pox virus remains dormant in the body.
Most infected children will have a rash, high fever, cough, runny nose, and watery eyes.
For every 1,000 children who get it, 1 or 2 will die from it
Spreads so easily that any child who is not immunized will probably get it, either now or later in life.
Non-cancerous skin growths caused by a viral infection in the top layer of the skin. Viruses that cause them are called human papillomavirus (HPV).
HSV-2 usually produces only mild symptoms or signs or no symptoms at all.
However, HSV-2 can cause recurrent painful genital sores in many adults, and HSV-2 infection can be severe in people with suppressed immune systems.
Regardless of severity of symptoms, genital herpes frequently causes psychological distress in people who know they are infected.
The most common serious liver infection in the world.
It is caused by the HBV virus that attacks the liver.
HBV is 100 times more infectious than the AIDS virus. Yet, can be prevented with a safe and effective vaccine.
1. First Level of Response: skin, mucous linings of respiratory tract
5. Antigen – foreign substance that induces immune response
7. Phagocytosis – the digestion of an antigen by an immune response cell
--Organism living on, in, or at the expense of another living organism