1. Mucocilliary action of the nasal pharyngeal area
2. Salivary action and swallowing will send pathogens to stomach to be destroyed

• Toxic proteins produced by some bacteria (mostly gram-positive) and secreted or released after lysis
• Effect on body: specific for a particular cell structure or function in the host (mainly affects cell functions, nerves, and GI)
• High toxicity
• Is NOT fever producing

• Part of the outer portion of the cell wall (lipid A) of most gram-negative bacteria, released on destruction of the cell
• Present in LPS of outer membrane of cell wall
• Effect on body: fever, weakness, aches, and shock
• Low toxicity

• Rhinoviruses (Picomaviridae) - most common
• Coronaviruses (Coronaviridae) - 20% of colds
• Incidences decrease with age, immunity based on a ratio of IgA antibodies to single serotypes
• Infection can spread to the sinuses , LRT, and middle ear

• Pharyngitis: inflammation of throat's mucous membranes
• Microbes that cause pharyngitis can also cause tonsilitis
• Throat becomes sore because the mucosa is infected or because of inflammatory and immune responses in the lymphoid tissue

• CMV (pharyngitis)
• Largest human herpes virus (Herpesviridae)
• Acquired most from bodily secretions  and blood
• Persistant and latent infections --> remains latent in neutrophils, T-cells, monocytes
• Often asymptomatic but can spread to lymphoid tissue (agranulocytes in spleen, lymph nodes), then salivary glands, kidneys, reproductive organs
• Dangerous to babies (mental retardation, congenital abnormalities), immune impaired

• Streptococcus pyogenes
• Gram (+)
• Facultative anaerobe
• S. pyogenes also infects other areas of the URT, skin, kidneys, etc.
• Produces many exotoxins and enzymes (streptolysins)
• Causes most sore throats
• It can spread, causing rheumatic fever, rheumatic heart disease

• Herpesvirus
• Transmitted in saliva
• Replicates in B-cells
• Virus is shed in saliva from infected salivary gland and oropharynx epithelial cells --> spreads to B-cells in lymphoid tissue
• T-cells respond to infected B-cells and become hyperplastic
• Infectious Mononucleosis (fever, anorexia, lethargy, splenic rupture)

• Paramyxoviridae
• Typically airborne or salivary secretion transmission; lytic infection
• Life-long resistance to reinfection

• May be caused by Pseudomonas aeruginosa
• Gram Negative
• Bacillus, aerobic
• Produces both exotoxins and endotoxins
• Can be caused by Staphylococcus aureus and Candida albicans ; all of these found as normal flora of the skin

1. Streptococcus pneumoniae
Gram Positive
Facultative anaerobe

2. Haemophilus influenzae

Gram Negative

Facultative anaerobe

3. RSV (respiratory syncytial virus)

4. Streptococcus pyogenes

• Sinuses have mucous membranes that are continuous with the nasal cavity
• Pathogenesis similar to otitis media
• Facial pain, sinus headaches

• H. influenzae normally
• Typically small children

• Usually the parainfluenza virus
• Streptococcus pyogenes
• S. pneumoniae
• Pain during inhalation/exhalation, hoarseness