1. Microbial Diseases of the Respiratory System

2. Respiratory System

3. Division of the Respiratory System
Upper respiratory system
Nose and throat

4. Lower respiratory system
Contains the larynx, trachea, bronchial tubes, and lungs

5. Diseases of the Upper Respiratory System
Pharyngitis – sore throat
Laryngitis – infection of the larynx
Tonsillitis – infection of the tonsils
Epiglottitis – infection of the epiglottis

6. Streptococcal pharyngitis
Streptococcus pyogenes
Beta hemolysis on blood agar from throat swab
Sore throat, fever, swelling of tonsils and neck
Penicillin

7. Streptococcal throat inection

8. Hemolytic reactions

9. Diphtheria Corynebacterium diphtheriae
Fever, sore throat, malaise, swelling of the neck
Tough grayish membrane forms in the throat from the infection
DTaP vaccine
Few cases in the US
Erythromycin or penicillin

10. Diphtheria prevalence

11. Otitis Media Middle ear infection Common in young children
Bacteria enter the middle ear from the oropharynx via the short internal auditory tube
Painful swelling of ear drum
Various bacteria cause the condition, mainly Streptococcus and Staphylococcus
Children generally outgrow the condition
Amoxicillin is used but this treatment is currently being phased out to limit resistance

12. Common cold Viral disease of the upper respiratory system
Caused by a variety of viruses; rhinoviruses and coronaviruses are the most common
Symptoms are sneezing, runny nose, and congestion
Exact route of transmission is still not clear
Viruses prefer a slightly cooler temperature hence the upper respiratory system
Self-limiting, 7days or so?

13. Pertussis (Whooping Cough)
Bordetella pertussis
Lower respiratory system disease
Bacterial toxin causes paralysis of tracheal cilia
Severe coughing to clear airway
Three stages of the disease: catarrhal, paroxysmal, and convalescence
DPT vaccine

14. Whooping Cough Prevalence in the U.S.

15. Mycobacterium tuberculosis

16. Tuberculosis
Lung infection caused by the acid-fast bacteria Mycobacterium tuberculosis
Acquired by inhalation
Strong immune system often will prevent the bacteria from causing infection
Weak immune system or poor general health can lead to infection and possibly death

17. Pathogenesis of TB
Bacteria are ingested by lung macrophages but are not killed
Bacteria multiply inside the macrophages
Infected macrophages are isolated in the lungs in lesions called tubercles
The tubercles can rupture and release bacteria into the body to cause systemic disease and infection to others
Symptoms include weight loss, coughing blood, loss of vigor, wasting and death
CONSUMPTION

18. Treatment
Long term antibiotic therapy with antibiotic such as isoniazid, rifampin, and pyrazinamide
Vaccination with the BCG vaccine
Vaccine effectiveness is questionable; used in much of the world except the US

19. TB Testing Tuberculin skin test is used to screen for the disease
Test results:
+ if you have had TB
+ if you have been exposed but never had active TB
+ if you have been vaccinated
- never had or been exposed to the disease

21. Incidence of TB 20,000 new cases in the US each year
Incidence decreasing in the US
Estimated 1/3 of the world population is infected
10-12 million deaths per year from TB
Antibiotic resistant strains are emerging

22. Bacterial pneumonia Streptococcus pneumoniae is the most common cause
Capsule around the bacteria causes virulence
Symptoms are high fever, chest pain, difficulty breathing
High mortality rate in elderly patients
Vaccine is available
Antibiotic treatment with penicillin

24. Mycoplasma pneumonia
Atypical pneumonia caused by the bacteria Mycoplasma pneumoniae
Bacteria has no cell wall
More common in young adults (under 40) and children
Symptoms are low grade fever, cough, headache that may last for several weeks
Treated with erythromycin and tetracycline

25. Legionellosis (Legionnaries’ disease)
Legionella pneumophila
High fever, cough
Air conditioning systems, and other water features
Spread through air (aerosol), not person to person
Philadelphia outbreak affected 34 deaths

26. Spread of Legionnaires’ Disease

27. Influenza

28. What is influenza? RNA virus that has three classes Influenza A
Disease in humans, can cause pandemics
Influenza B
Inflects humans, less severe than type A
Influenza C
Infects pigs and humans, generally mild disease

29. Structure of the flu virus
RNA virus
Outer lipid coat
Projections on the outer layer
Hemagglutin spikes (H) 16 types
Neuraminidase spikes (N) 9 types

30. Spikes Hemagglutinin spikes 500 per virus
Allows virus to recognize and attach to body cells
Antibodies made to these spikes
Neuraminidase spikes
100 per virus
Help virus separate from infected host cell

31. Why do I need to get a new flu shot every year?
Antigenic drift – changes in the structure of the spikes that allow the virus to evade the immune system
Occurs on an annual basis
Antigenic shift – major change in the protein of the spikes that creates a virus that is “new” to the human population; little herd immunity; major epidemics

32. Flu shots/Flu season

33. Coccidiodomycosis Fungal disease of the lungs Coccidiodes immitis
Endemic to the desert southwest
Causes either no symptoms or mild symptoms, including chest pain, fever, coughing, and weight loss
Immune suppressed individuals may develop a TB like disease that can become systemic
Amphotericin B is used to treat the condition

34. Coccidioidomycosis