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What normal microbiota of the upper respiratory system may become opportunistic pathogens?
- Nose: Haemophilus influenza, Staphylococcus aureus(1/3 healthy americans)
- Upper pharynx: Streptococcus pneumonia
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Signs and symptoms of Strep throat? Streptococcal respiratory disease
- back of pharynx is red, swollen lymph nodes
- pus- containing abscesses on tonsils
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What causes Scarlet Fever? Streptococcal respiratory diseases
strains of Streptococci carry a lysogenic virus that produce toxins.
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What disease complications can occur if strep throat is not treated?
- acute glomerulonephritis= kidney disease
- rheumatic fever= damage heart valves & muscle
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Whats pathogen is the major cause of sore throat and scarlet fever, rheumatic fever, and glomerulonephritis?
Streptococcus pyogenes= Group A
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How are the many species of streptococci differentiated?
- serology and type of hemolysis on blood agar
- B= clear
- a= green
- Streptococcus pyogenes is Lancefield's serological "Group A" and B hemolytic
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How is strep throat spread?
respiratory droplets
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How is strep throat diagnosed and treated?
immunological test- penicillin
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can a person have strep throat more than once?
yes
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Are all cases of pharyngitis (sore throat) actually strep throat?
No
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What are the signs and symptoms of diptheria?
sore throat
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What is the pseudomembrane? diptheria
- blood clothing factors
- leukocytes
- bacteria and dead cells
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What is the pathogen that causes diptheria?
Corynebacterium diphtheriae
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Why do bacteria look like Chinese letters? diptheria
- Snapping division
- help identify the organisms
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How is the pathogen transmitted?diptheria
direct contact or respiratory droplets
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What are the pathogens that usually cause sinusitis and otitis media, and where do they come from (what part of body)?
- Streptococcus pneumoniae, S. aureus, Haemophilus influenza, moraxella catarrhalis
- =pharynx
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Which disease (sinusitis or otitis media) is more common in adults, and which is more common in children?
- adults= sinusitis
- children= otitis
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What are the signs and symptoms of the common cold?
Sneezing, runny nose, congestion, sore throat, malaise, cough
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What are the pathogens of the common cold?
- 200 different viruses
- rhinoviruses
- cornaviruses
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Can cold viruses infect the lower respiratory tract?
- No, because of the higher temp.
- effective at 33C
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Why is it difficult to produce antibodies to the attachment sites on cold viruses?
attachment sites are hidden deep and its difficult for them to attach
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Once the virus attaches to cells lining the nasal cavity, what happens? cold
- signals reproduction of many more viruses and infect neighboring cells.
- amplification
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How are the cold viruses spread? and most common?
- single particle: coughing, sneezing, fomites
- Most common: hand-to-hand contact
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What is the most important preventative measure for colds?
hand washing
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Pneumonia?
inflammation of the lungs
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lobar pneumonia?
- means a lobe is involved
- inflammation of the lungs
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Nosocomial pneumonia
- means it was acquired in a hospital setting
- inflammation of the lungs
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What are the signs and symptoms of pneumococcal pneumonia?
- usually lobar fever, chills, congestion, cough, chest pain, short rapid breathing, nausea, vomit
- sputum
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what is the pathogen that causes most cases of pneumonia?
Streptococcus pneumoniae= pneumococcus
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How is the pathogen acquired, and who is most likely to become infected? pneumonia
- Normal microbiota 75% people
- Inhaled into lungs damaged by a previous viral disease(flu)
- elderly are more likely
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What is the means of treatment or prevention for pneumococcal pneumonia?
- penicillin drug choice
- CDC recommends a vaccine at 2,4,6 and 12-15 months of age and adults over 65
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What are the signs and symptoms of primary atypical pneumonia?
- fever, malaise, headache, sore throat, excessive sweating
- unreproductive cough
- walking pneumonia
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Describe the pathogen that causes primary atypical pneumonia?
Mycoplasma pneumonia
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How does the organism of primary atypical pneumonia cause disease? Mycoplasma pneumonia
attach to base of cilia and stops them from beating, which parents removal of mucus by ciliary escalator, causes buildup of mucus that irritate respiratory tract
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How is the pathogen of primary atypical pneumonia spread? Mycoplasma pneumonia
nasal secretions
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Is a vaccine available for Mycoplasma pneumonia?
no vaccine
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what are the signs and symptoms of TB?
- minor cough and fever
- breathing difficulty, fatigue, malaise, weight loss, chest pain
- wheezing, cough blood
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What is causative agent of TB?
- Mycobacterium tuberculosis:
- acid fast stain
- mycolic acid, cell wall, waxy
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How long can the pathogen Mycobacterium tuberculosis live outside the body?
8 months - dried aerosol droplets
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M. tuberculosis is not very virulent, but if the disease does occur, what percent of untreated patients die?
55% of people
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Describe the 3 types of TB?
- Primary TB – small, hard nodules are formed (tubercles) in the lungs – bacteria may remain dormant inside these tubercles for decades; replicate inside phagocytes
- Secondary or reactivated TB - Tubercle is ruptured and the bacteria spread through the lungs
- Disseminated TB –macrophages carry the bacterium to other places (bone marrow, spleen, kidneys, spinal cord, and brain
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Describe the tuberculin skin test including:
what is injected into the skin?
what is a positive result?
what type of hypersensitivity response and what does a positive response mean?
- screens for exposure to TB
- cells walls of m.tuberculosis
- red, swollen, painful bump
- Type IV hypersensitivity
- positive mean it has the antigens
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What other tests are used to diagnose TB?
- chest X-ray
- acid fast sputum
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what are the two primary drugs used to treat TB, and how long does treatment last?
- isoniazid (INH), rifampin
- 6 months
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What are MDR and XDR strains? Tuberculosis
- Multi-drug-resistant (MDR) strains:
- Resistant to INH and rifampin
- Have arisen in several countries
- Extensively drug-resistant (XDR) TB is even worse:
- Resistantto INH, rifampin and 3 or more anti-TB drugs
- In S. Africa, 52 of 53 patients died
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Is there a vaccine for TB? what is DOTS?
- Yes, BCG vaccine
- Directly Observed Treatment Shortcourse: has reduced incidence in US
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What are the signs and symptoms of the Flu?
- Incubation period of 1 day
- Fever of 102-106°F, pharyngitis, congestion, dry cough, malaise, headache, and muscle soreness
- Lasts for 1-2 weeks
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What are the pathogens that cause the flu?
- orthomyxoviruses –Types A and B
- Virus has spikes composed of hemagglutin (HA) or neuraminidase (NA) – provide attachment
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What are HA and NA, and what is their function?
- Influenza virus budding from a cell.
- Glycoprotein spikes are neuraminadase (NA)
- hemagglutinin (HA)
- Variations In these determine the type of virus.
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what is antigenic drift?
is the result of mutations in the HA and NA genes – results in a slow, gradual change in viral antigens
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what is antigenic shift?
- is a major antigenic change that results from reassortment of genes from different influenza
- A viruses infecting the same host cell (either human or animal [e.g., birds, bats o
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how are influenza viruses named?
- Type (A or B)
- Location and date of original identification
- Type of antigens (HA and NA)
- For example, A Singapore/1/80 (H1N2)
- Ifisolated from an animal, it may also get a common name, like Hong Kong flu or swine flu
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why is there concern about H5N1 flu virus?
- Has spread over Asia, Africa, North America, and Europe
- Fatal 50% of the time in humans, but rarely spreads from human to human (humans get it from birds)
- Deadly nature of the virus and the speed with which it has spread around the world cause epidemiologists to predict the arrival of a major pandemic like that of 1918
- If it mutates to allow easy passage between humans, this could be a huge health challenge
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what are the signs and symptoms of valley fever?
- Initially resembles pneumonia or TB
- 60% get mild, respiratory symptoms that resolve on their own
- Others develop severe infections – fever, cough, chest pain, difficulty breathing, coughing up blood, headache, night sweats, weight loss and pneumonia; some get a rash
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what is the causative agent of valley fever?
Coccidioides immitis – a soil fungus that grows like a mold, and like a yeast at body temperatures
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how is the pathogen of valley fever acquired?
Inhalation of asexual spores from dust
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what percent of population in endemic areas develop the disease valley fever?
- 3% of people living in endemic areas develop the disease each year
- Anything that disrupts the soil can spread the spores
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what is the treatment for valley fever?
- Identification in specimens
- Usually resolves on its own, but when spreads to brain and spinal cord is fatal if untreated
- Amphotericin B is the drug of choice: very toxic
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what is the most common fungal systemic disease affecting humans?
Histoplasmosis
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what are the signs and symptoms of histoplamosis?
- Asymptomatic in 95% of people and resolves without damage
- 5% develop severe coughing with blood-tinged sputum or skin lesions
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how is histoplasmosis acquired?
- Histoplasma capsulatum- a soil fungus that becomes a yeast at body temperatures
- Found in bat and bird droppings
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