Week 2 Notes, Friday
Week 2 Notes, Friday PHE 363
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This 4 page Class Notes was uploaded by Chalcedonia Neufeld on Saturday October 8, 2016. The Class Notes belongs to PHE 363 at Portland State University taught by Claire Wheeler in Fall 2016. Since its upload, it has received 4 views.
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Date Created: 10/08/16
PHE 363-Communicable & Chronic Disease Claire Wheeler #13220 Date: Friday October 7, 2016 Damage done by Infections Virulence-Specialized and complex pathogenic mechanism of virus and bacteria’s Influenza Virus- Kills the cells lining the airwayleaving gaps in the epithelial cellsAllowing bacteria into lungs Polio also does this- Cytopathic mechanism, attacks nerve cells Types of Infection- Acute: develops and runs its course quickly. Tend to not have permanent affect. Chronic: develops, long slow, debilitating condition Latent: periods of no symptoms b/w outbreaks of illness Ex)Hep B Local or Systemic Infection??? Local:confined to a specific area of the body (stubbed toe) Systemic: illness infecting most of the body with pathogens distributed widely in tissues Classifying Diseases *Classification is done by timing *Viruses only attack one cell in the body-named after the body part they attack. Primary:Initial infection (influenza, Chicken pox) Secondary: infection occurs in person weakened by a primary infection (pneumonia, Secondary staph skin infection) All Infectious diseases happen in stages-determined by body’s response *Incubation Period: Time b/w infection and appearance of signs and symptoms (you are infected and contagious, may not know you are infected) *Prodromal Phase: Mild, nonspecific symptoms, mediated by the immune system/cytokines in brain (Macrophages are starting to secrete cytokines for amplification of symptoms) o Symptoms in this stage are primarily caused by immune activation. *Clinical Phase: Typical signs and symptoms of disease (usually two weeks) *Decline Phase *Recovery Phase Diagnosis of Infectious Illness 1. Isolate pathogen form the patient 2. Examine sample microscopically & Identify a. Gram stain is widely used to classify Bacterias (certain types need a specialized strain-Tuberculosis) 3. Grow it in culture in the lab a. Can take days to accomplish testing. b. Culture is critical for antibiotic sensitivity testing 4. Test antibiotics on the culture a. Purpose: Find the best drug treatment for Infection b. Very Important! Extremely important due to high prevalence of antibiotic resistance organisms Common Test’s: *Gram positive or negative? (Decide based on Presumption) *Urinary test *Xray *Presumptive treatment: Presume to know the cause of illness and treat accordinglyCommon when you need rapid treatment for patient. ANTIOBIOTICS!! *Penicillin- Works by attacking the cell wall of the bacteriaGreat because we do NOT have cell walls, therefore Penicillin does not attack the body’s Self Cells. Bacteria! Cyanobacteria-fossils 3.5 billions years old (very old life form) *Nitrogen Fixation o Essential for plant life o Single Cell Organisms, Contain Cell Wall o Virulence Factor = Ability to be mobile, having cilia or flagella o Extremely adaptable, Can make Spores to exist outside of host for long periods of time (little eggs/shells)-Ex)Botulism and Tetanus o Bacterial Reproduction o Simple binary fission providing two identical cells (same copy of bacterial cell). o Division time varies by species form 20 minutes to 2 weeks o Divide 10 to 100 times faster than human cells o Colonies can grow quickly after invading human tissue Bacterial Genetics NO membrane bound DNA and NO chromosomes Plasmids (loops/rings) are easily transmitted Not organized like humans, leading to frequent mutation (change over time with more reproduction) Antibiotic Resistance Give each other DNA “rings” to create a mutation for resistance. “Plasmid Transfer” BioFilm Biofilm: Bacteria attached to a surface and produce sugary/mucousy slime o Protects form being taken off, Very persistent in growth o Close together with High surface area & increase in strength o Very close to each other Confer resistance by transferring plasmids Stable structure is formed, allowing for optimal growth of bacteria (Ex- Coral reef) Function goes from unicellular to multi-cellular The bacteria begin to interact and cooperate with each other Examples of Biofilms in Humans 1. Dental Plaque o Very powerful! Takes steel tools to scrape off. o Dental plaque Increase’s the risk of heart disease/widespread inflammation of the gums o Inflammation causes increase in cytokines, traveling everywhere *Very important to get teeth cleaned regularly! 2. Catheter Infections: Any catheter passing epithelial entrance/barrier o Must be changed every 2-3 days o *Very sterile technique is important! o *Significant cause of hospital acquired and mortality PROBLEMAntibiotics DO NOT penetrate the structure very efficiently Virulence Factors #1-Modes of Transmission Viral & Bacterial More deadly pathogens need to find clever ways to move form a very sick host to a new host. Frequently accomplished by using Vectors like mosquitoes and Malaria Milder illness like common cold tend to be transmitted person to person-with the host being mobile Not as deadly but use this to be transmitted #2-Adherence Factors Viral & Bacterial Virus and Bacteria must be able to bind to host cells in order to establish an infection The active infection occurs ON the epithelial surface (Surface Invasion) -By inflammation, tight jnx. are loosened -Also are able to ATTACH on the epithelial cells and move down into the basement membrane and appearing on the surface (Ex- Strep Throat) #3-Invasion Factors Strictly Bacterial, by an exotoxin the bacteria secretes. Bacteria secretes a chemical that erodes and eats the bodies tissues. Terminology: Parasitism: Good for parasite, Bad for Host Mutualism: Serves host and parasite Acute: develops and runs its course quickly. Tend to not have permanent affect. Chronic: develops, long slow, debilitating condition Latent: periods of no symptoms b/w outbreaks of illness Ex)Hep B Local:confined to a specific area of the body (stubbed toe) Systemic: illness infecting most of the body with pathogens distributed widely in tissues
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