Diseases & infections of the Respiratory System

What four bacterial diseases of the upper respiratory tract

Streptococcal Pharyngitis, Scarlet Fever, Diptheria, Otitis Media

Infections of the ____ ______ ____ are the most common type of infection

upper respiratory system

What can pathogens infect when they enter the respiratory system?

other parts of the body

Upper respiratory consists of:

nose, pharynx, middle ear, auditory tubes

Lower respiratory system consists of:

trachea, bronchial tubes, alveoli

List the five forms of protection of the respiratory system

• course nose hairs

• ciliated mucous membranes

• lymphoid tissue, tonsils, adenoids

• alveolar macrophages

• respiratory mucus contains IgA antibodies

What is the function of IgA antibodies in respiratory mucus?

initiate inflammatory response

Describe the normal flora of the upper respiratory system

usually contains pathogenic microbes

Describe the normal flora of the lower respiratory tract

Was thought to be sterile, but it isn’t

Why does the respiratory tract harbor a large number of commensal organisms?

due to constant contact w the environment

Metagenomic analysis reveals that both the upper & lower respiratory tracts harbor over ____ bacterial genomes per sample

2,000

How many bacterial genera make up a significant portion of the normal biota?

9

Normal flora plays a significant role in microbial ______

antagonism

antagonism

• effect of “good” microbes against intruder microbes

  • Often members of “normal flora”

  • Prevent overgrowth of intruder microbes

What is pharyngitis

Strep throat - inflammation of the mucus membranes & fever

• occasionally tonsillitis & otitis media

What are signs/symptoms of pharyngitis?

inflammatory pockets visible on the walls of the throat, difficulty swallowing, foul breath

Viral pharyngitis

mild & lead to hoarseness

Bacterial pharyngitis is caused by…

Streptococcus pyogenes

Bacterial pharyngitis

• more painful

• often accompanied by fever

• headache

• nausea

Pharyngitis: virulence factors

• proteins that aid in attachment

• enzymes that damage & lyse host cells &/or degrade DNA

How can pharyngitis be spread? (3)

direct contact, droplets, fomites

What bacteria causes scarlet fever?

also caused by S. pyogenes

What is S. pyogenes infected by in scarlet fever? What is produced?

S. pyogenes infected by bacteriophage

• produces erythrogenic toxin (poisonous toxins)

What are symptoms/signs of scarlet fever? (3)

• red rash

• high fever

• red enlarged tongue

What causes diphtheria?

caused by exotoxin producing Corynebacterium diphtheriae

When is the exotoxin produced by Corynebacterium diphtheriae?

when lysogenized by a phage

What forms in the throat in diphtheria? Why is this concerning?

• a membrane containing fibrin & dead human/bacterial cells form in the throat

• it can block air passage

What does the exotoxin in diphtheria inhibit? What can result from this?

• exotoxin inhibits protein synthesis

• May result in heart & kidney damage

What is the vaccination for diphtheria?

DTaP vaccine

What is otitis media?

• earache

• pus accumulation on tympanic membrane

What causes otitis media?

caused by numerous Staph & Strep species

• mixed infection - biofilms

What is the vaccine for otitis media?

S. Pneumoniae

What otitis media vaccine is recommended for children under 5 years?

Pneuomococcal conjugate vaccine (PCV)

What otitis media vaccine is recommended for adults & older children?

Pneumococcal polysaccharide vaccine (PPSV)

What are 3 bacterial diseases of the lower respiratory system?

• Pertussis

• Tuberculosis

• Bacterial Pneumonia

Pertussis is also known as…

Whooping cough

What bacteria causes pertussis?

Bordetella pertussis

How contagious is pertussis?

highly contagious

What is pertussis? Signs/sympyoms?

• accumulation of mucus in trachea & bronchi cause a deep cough

• initially resembles a cold (Catarrhal phase)

• Severe coughing (Paroxysmal phase)

What are the two symptom phases of pertussis?

• 1: Catarrhal phase - resembles a cold (3-21 day incubation)

• 2: Paroxysmal - severe coughing (1-2 weeks after catarrhal)

In pertussis, accumulation of mucus in trachea & bronchi cause a deep cough, which causes damage to what?

damages cilia on epithelia cells

Pertussis is convalescing. What does this mean?

susceptible to secondary infection

Pertussis: virulence factors

• adhesions

• toxins that interfere with signaling pathways

• paralysis to immune cells

• damages & kills epithelial cells

• tissue necrosis

What is the vaccine for pertussis? At what age can you get a booster?

• DTaP vaccine

• can get booster at age 11

What bacteria causes tuberculosis?

Mycobacterium tuberculosis

What happens to the bacteria in tuberculosis?

ingested by alveolar macrophages, if not killed they reproduce inside the macrophage

Sign of tuberculosis

Ghon’s complex - scarring

What is the treatment for tuberculosis?

chemotherapy for 6 months

How do you test for tuberculosis? What evidence does it show? How does it work?

Mantoux test - shows evidence of delayed hypersensitivity after initial infection w TB

• Purified protein derivative is injected under the skin & observed for evidence of an induration indicating delayed hypersensitivity

Most common mode of transmission for tuberculosis

vehicle (airborne)

What causes bacterial pneumonia?

S. pneumonia normally, but can be caused by others

what can lead to H. influenza?

alcohol, poor nutrition, cancer, diabetes

What does bacterial pneumonia cause?

• increase mucus production

• decreased oxygen saturation levels

Bacterial pneumonia: virulence factors

• promote adherence

• invasion of host tissues, allows it to escape immune defenses

Viral disease of the upper respiratory tract

common cold

How many different viruses include the common cold? Which is the cause 50% of the time? What are symptoms of the common cold? When is there an increase?

• 200 different viruses

• Rhinovirus 50% of the cause

• sneezing, nasal secretions, congestion

• increase in wintertime

When does rhinovirus grow best?

at slightly lower than body temperature

Viral disease of the lower respiratory system

Viral pneumonia

what causes viral pneumonia?

numerous viruses

Respiratory syncytial virus (RSV)

• infects respiratory tract & produces giant multinucleated cells

When is peak incidence of RSV?

winter & early spring

For RSV, what groups is mortality the highest for?

premature infants, those with congenital disease, or immunodeficiency

How contagious is RSV?

highly contagious

How is RSV spread?

droplet contact, fomites

Symptoms of the cold

• cough

• stuffy/runny nose

• sore throat/ears

• headache

• red eyes

• loss of appetite

• irritability

• some children develop fever

Symptoms of the flu

• cough

• stuffy/runny nose

• body ache

• shivering

• feeling hot/cold

• fatigue

• diarrhea or vomiting

• symptoms can be more severe than cold

RSV

• cough

• stuffy/runny nose

• sneezing

• wheezing

• fever

• can cause severe illnesses (bronchiolitis, pneumonia)

Influenza