Infectious Diseases of the Respiratory System

Infectious Diseases of the Respiratory System

Infections of the Respiratory tract
* Most common entry point for infections
* Upper respiratory tract
* Lower respiratory tract


Protective Mechanisms
Normal flora: Commensal organisms
* Limited to the upper tract
* Mostly Gram positive or anaeorbic
* Microbial antagonist (competition)

Other Protective Mechanisms
* Nasal hair, nasal turbinates
* Mucus
* Involuntary responses (coughing)
* Secretory IgA
* Immune cells

Selected Bacterial Infections

Pharyngitis
Pneumonia - Streptococcus pneumoniae
Diphtheria - Corynebacterium diphtheriae
Tuberculosis - Mycobacterium tuberculosis
Whooping cough - Bordetella pertussis
Streptococcus pyogenes
Group A Strep
Strep Throat
Scarlet Fever
Bacterial Pneumonia
Streptococcus pneumoniae
Bacterial Pneumonia
Streptococcus pneumoniae
Diphtheria
* Transmitted by droplets or fomites
* Infects the upper respiratory tract
* Begins with severe sore throat, low-grade fever and swollen lymph nodes or with skin rash, 1-6 days after infection

Corynebacterium diphtheriae
* Aerobic Gram + bacillus
* Toxin inhibits protein synthesis of cells to which it binds
* Destroyed cells and WBC form "pseudomembrane" which blocks airways
Bordetella pertussis
Pertussis (Whooping Cough)
Mycobacterium tuberculosis
Tubercule formation
Tuberculosis
Multi-Drug Resistant
TB Skin Test
Virus infections
Fungal Infections
Respiratory Syncytial Virus
* Enveloped (membrane) RNA virus
* Spread by respiratory droplets
* Community outbreaks in late fall to spring
* Upper respiratory tract infection – epithelial cells
* May be fatal in infants
Influenza Virus
An enveloped RNA virus
Coccidioides immitis
Valley Fever is an Endemic Disease
Coccidioides immitis

Infectious Diseases of the Respiratory System.ppt