Chapter 23, Chapter 24

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Chapter 23, Chapter 24

• Microbial Diseases of the Cardiovascular and
  Lymphatic Systems
• Microbial Diseases of the Respiratory System

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The Cardiovascular System

• Blood is a mixture of plasma and cells.

• White blood cells are involved in the bodys
  defense against infection.

Red blood cells carry oxygen
Figure 23.1
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The Lymphatic System

• Fluid that filters out of capillaries into spaces
  between tissue cells is called interstitial
  fluid.

Interstitial fluid enters lymph capillaries and
is called lymph vessels called lymphatics return
lymph to the blood.
Figure 23.2
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Sepsis and Septic Shock

• Sepsis is an inflammatory response caused by the
  spread of bacteria or their toxin from a focus of
  infection.
• Septicemia is sepsis that involves proliferation
  of pathogens in the blood.
• Septic shock- low blood pressure which cannot be
  controlled

Lymphangitis
Figure 23.3
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Sepsis

• Gram-negative sepsis
• Endotoxins caused blood pressure decrease and
  septic shock .
• Antibiotics can worsen condition by killing
  bacteria
• Gram-Positive Sepsis
• Nosocomial infections, exotoxins
• Staphylococcus aureus
• Streptococcus pyogenes
• Group B streptococcus
• Enterococcus faecium and E. faecalis

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Sepsis

• Puerperal Sepsis (Childbirth fever)
• Streptococcus pyogenes
• Puerperal sepsis begins as an infection of the
  uterus following childbirth or abortion it can
  progress to peritonitis or septicemia.
• Puerperal sepsis was transmitted by the hands and
  instruments of midwives and physicians.
• Puerperal sepsis is now uncommon because of
  modern hygienic techniques and antibiotics

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Bacterial Infections of the Heart

• The inner layer of the heart is the endocardium.
• Inflammation of the endocardium
• Endocarditis
• Subacute bacterial endocarditis
• from microbs in the mouth.( Arises from a focus
  of infection, such as a tooth extraction).
• alpha-hemolytic streptococci
• staphylococci
• enterococci
• Preexisting heart abnormalities
• are predisposing factors.
• Signs include fever, anemia, and heart murmur.
• Acute bacterial endocarditis
• Staphylococcus aureus
• The bacteria cause rapid destruction of heart
  valves

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Rheumatic Fever

• Rheumatic fever is an autoimmune complication of
  streptococcal infections.
• Rheumatic fever is expressed as arthritis
• or inflammation of the heart.
• It can result in permanent heart damage.
• Rheumatic fever can follow a streptococcal
• infection, such as streptococcal sore throat.
• Streptococci might not be present at the
• time of rheumatic fever.
• Prompt treatment of streptococcal infections can
  reduce the incidence of rheumatic fever.
• Penicillin is administered as a preventive
  measure against subsequent streptococcal
  infections.
• Antibodies against group A beta-hemolytic
  streptococci react with streptococcal antigens
  deposited in joints or heart valves or
  cross-react with the heart muscle.

Figure 23.5
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Zoonotic disease

• Tularemia-
• Francisella tularensis, gram-negative rod
• Bacteria reproduce in phagocytes
• Transmitted from rabbits and deer by deer flies
• Brucellosis (Undulant Fever)
• Brucella, gram-negative rods that grow in
  phagocytes,
• B. abortus (elk, bison, cows),
• B. suis (swine),
• B. melitensis (goats, sheep, camels)
• Undulating fever that spikes to 40C each evening
• Transmitted via milk from infected animals or
  contact with infected animals

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Anthrax

• Bacillus anthracis,
• gram-positive,
• endospore-forming aerobic rod
• Found in soil
• Cattle are routinely vaccinated
• Treated with ciprofloxacin or doxycycline
• Cutaneous anthrax
• Endospores enter through minor cut
• 20 mortality
• Gastrointestinal anthrax
• Ingestion of undercooked food contaminated food
• 50 mortality
• Inhalational anthrax
• Inhalation of endospores
• 100 mortality

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Gangrene

• Ischemia
• Loss of blood supply to tissue
• Necrosis
• Death of tissue
• Gangrene
• Death of soft tissue
• Gas gangrene
• Clostridium perfringens,
• gram-positive,
• anaerobic rod,
• endospore-forming
• grows in necrotic tissue
• Treatment includes surgical removal of necrotic
  tissue and/or hyperbaric chamber

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Animal bites and scratches

• Pasteurella multocida
• Clostridium
• Bacteroides
• Fusobacterium
• Cat-scratch disease
• Bartonella hensellae

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Plague

• Plague - Yersinia pestis,
• gram-negative rod
• grow in blood and lymph
• Transmitted by rat flea
• Septicemia plague-Septic shock
• Pneumonic plague-Bacteria in the lungs

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Lyme Disease

• Borrelia burgdorferi
• Reservoir
• Deer
• Vector
• Ticks

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Lyme Disease
Figure 23.13a
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Lyme Disease

• First symptom
• bull's eye rash
• Second phase
• Irregular heartbeat
• Encephalitis
• Third phase
• Arthritis

Figure 23.14
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Rickettsias

• The human body louse Pediculus humanus corporis
  transmits Rickettsia prowazekii in its feces,
  which are deposited while the louse is feeding
• Epidemic typhus is prevalent in crowded and
  unsanitary living conditions that allow the
  proliferation of lice.
• The signs of typhus are rash, prolonged high
  fever, and stupor - Tetracyclines and
  chloramphenicol are used in treatment.
• Endemic murine typhus is a less severe disease
  caused by Rickettsia typhi and transmitted from
  rodents to humans by the rat flea.
• Spotted Fevers (Rocky Mountain spotted fever)
   -Rickettsia rickettsii is a parasite of ticks
  (Dermacentor spp.) in the southeastern United
  States, Appalachia, and the Rocky Mountain
  states.
• The rickettsia may be transmitted to humans, in
  whom it causes tickborne typhus fever.
• Chloramphenicol and tetracyclines effectively
  treat Rocky Mountain spotted fever, or tickborne
  typhus.
• Serological tests are used for laboratory
  diagnosis.

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Viral Diseases of the Cardiovascular and
Lymphatic Systems 

• Burkitt lymphoma is a cancer of the lymphatic
  system (in particular, B lymphocytes).
• It is named after Denis Burkitt, a surgeon who
  first described the disease in 1956 while working
  in equatorial Africa.
• Epstein-Barr virus (Human herpesvirus 4)
• The endemic variant occurs in equatorial Africa.
  It is the most common malignancy of children in
  this area.
• Children affected with the disease often also
  had chronic malaria
• Disease characteristically involves the jaw or
  other facial bone, distal ileum, cecum, ovaries,
  kidney or the breast.
• The sporadic type of Burkitt lymphoma (also known
  as "non-African") is another form found outside
  of Africa.
• It is believed that impaired immunity provides an
  opening for development of the Epstein-Barr
  virus.
• It accounts for 30-50 of childhood lymphoma. Jaw
  is less commonly involved, comparing with the
  endemic variant. Ileo-cecal region is the common
  site of involvement.
• Immunodeficiency-associated Burkitt lymphoma is
  usually associated with HIV infection or occurs
  in the setting of post-transplant patients who
  are taking immunosuppressive drugs.

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Infectious Mononucleosis

• Mononucleosis is caused by Epstein-Barr virus.
• The virus multiplies in the parotid glands and is
  present in saliva.
• It causes the proliferation of atypical
  lymphocytes.
• The disease is transmitted by the ingestion of
  saliva from infected individuals.
• Childhood infections are asymptomatic
• Diagnosis is made by an indirect
  fluorescent-antibody technique.
• EB virus may cause other diseases, including
  cancers and multiple sclerosis.

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Cytomegalic Inclusion Disease

• Cytomegalovirus (Human herpesvirus 5)
• Infected cells swell (cyto-, mega-)
• Latent in white blood cells
• Cause formation of distinctive inclusion bodies
• May be asymptomatic or mild
• Transmitted across the placenta, may cause mental
  retardation
• Transmitted
• sexually,
• by blood, or by transplanted tissue

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Viral hemorrhagic fevers

• Viral hemorrhagic fevers are caused by viruses
  from four distinct families.
• Range in severity from relatively mild to
  life-threatening.
• Begin with fever and muscle aches.
• Some viral hemorrhagic fevers progress to far
  more serious problems, including severe internal
  and external bleeding (hemorrhage), widespread
  tissue death (necrosis), and shock.
• No current treatment can cure viral hemorrhagic
  fevers, and immunizations exist for only two of
  the many VHFs

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Viral Hemorrhagic Fevers
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Protozoan Diseases of the Cardiovascular and
Lymphatic Systems

• ChagasDisease - Trypanosoma cruzi
• Reservoir-Rodents, opossums, armadillos
• Vector- Reduviid bug
• Leishmaniasis -Leishmania spp.
• Vector- SandfliesThe protozoa reproduce in the
  liver, spleen, and kidneys.
• Antimony compounds are used for treatment.
• Babesiosis - Babesia microti
• transmitted to humans by ticks.

Figure 23.22, 12.33d
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Toxoplasmosis

• Toxoplasmosis is caused by Toxoplasma gondii.
• T. gondii undergoes sexual reproduction in the
  intestinal tract of domestic cats, and oocysts
  are eliminated in cat feces.
• In the host cell, sporozoites reproduce to form
  either tissue-invading tachyzoites or
  bradyzoites.
• Humans contract the infection by ingesting
  tachyzoites or tissue cysts in undercooked meat
  from an infected animal or contact with cat
  feces.
• Congenital infections can occur. Signs and
  symptoms include severe brain damage or vision
  problems.
• Toxoplasmosis can be identified by serological
  tests, but interpretation of the results is
  uncertain.

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Malaria

• The signs and symptoms of malaria are chills,
  fever, vomiting, and headache, which occur at
  intervals of 2 to 3 days.
• Malaria is transmitted by Anopheles mosquitoes.
  The causative agent is any one of four species of
  Plasmodium.
• Sporozoites reproduce in the liver and release
  merozoites into the bloodstream, where they
  infect red blood cells and produce more
  merozoites.
• New drugs are being developed as the protozoa
  develop resistance to drugs such as chloroquine.

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Learning objectives

• Identify the role of the cardiovascular and
  lymphatic systems in spreading and eliminating
  infections.
• List the signs and symptoms of septicemia, and
  explain the importance of infections that develop
  into septicemia.
• Differentiate gram-negative sepsis, gram-positive
  sepsis, and puerperal sepsis.
• Describe the epidemiologies of bacterial
  endocarditis and rheumatic fever.
• Discuss the epidemiology of tularemia.
  Brucellosis and antrax.
• Discuss the epidemiology of gas gangrene.
• List three pathogens that are transmitted by
  animal bites and scratches.
• Compare and contrast the causative agents,
  vectors, reservoirs, symptoms, treatments, and
  preventive measures for plague, Lyme disease, and
  Rocky Mountain Spotted Fever.
• Identify the vector, etiology, and symptoms of
  five diseases transmitted by ticks.
• Describe the epidemiologies of epidemic typhus,
  endemic murine typhus, and spotted fevers.
• Describe the epidemiologies of CMV inclusion
  disease, Burkitts lymphoma, and infectious
  mononucleosis.
• Compare and contrast the causative agents, modes
  of transmission, reservoirs, and symptoms for
  Ebola hemorrhagic fever and Hantavirus pulmonary
  syndrome.
• Compare and contrast the causative agents, modes
  of transmission and reservoirs, for
  toxoplasmosis, malaria, leishmaniasis, and
  babesiosis.

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Structure and Function of the Respiratory System

• The upper respiratory system consists of
• Nose
• Pharynx
• Sinus
• middle ear and auditory tubes.
• Coarse hairs in the nose filter large particles
  from air entering the respiratory tract.
• The ciliated mucous membranes of the nose and
  throat trap airborne particles and remove them
  from the body.
• Lymphoid tissue, tonsils, and adenoids provide
  immunity to certain infections.

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Structure and Function of the Respiratory System

• The lower respiratory system consists of
• Larynx
• Trachea
• bronchial tubes
• alveoli.
• The ciliary escalator of the lower respiratory
  system helps prevent microorganisms from reaching
  the lungs.
• Microbes in the lungs can be phagocytized by
  alveolar macrophages.
• Respiratory mucus contains IgA antibodies.

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Microbial Diseases of the Upper Respiratory System

• Upper respiratory normal microbiota may include
  pathogens
• Laryngitis
• S. pneumoniae,
• S. pyogenes,
• viruses
• Tonsillitis
• S. pneumoniae,
• S. pyogenes,
• viruses
• Sinusitis
• Bacteria
• Epiglottitis
• H. influenzae

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Streptococcal pharyngitis

• Strep throat
• Streptococcus pyogenes
• Resistant to phagocytosis
• Streptokinases lyse clots
• Streptolysins are cytotoxic
• Pharyngitis - Scarlet Fever
• Erythrogenic toxin produced
• by lysogenized S. pyogenes
• Diagnosis by indirect agglutination

Figure 24.3
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Diphtheria

• Corynebacterium diphtheriae.
• exotoxin-producing
• Diphtheria
• A membrane, containing fibrin and dead human
• and bacterial cells, forms in the throat and can
• block the passage of air.
• The exotoxin inhibits protein synthesis,
• and heart, kidney, or nerve damage may result.
• Laboratory diagnosis is based on isolation of the
  bacteria and the appearance of growth on
  differential media.
• Antitoxin must be administered to neutralize the
  toxin, and antibiotics can stop growth of the
  bacteria.
• Routine immunization in the United States
  includes diphtheria toxoid in the DTaP vaccine.
• Slow-healing skin ulcerations are characteristic
  of cutaneous diphtheria.
• There is minimal dissemination of the exotoxin in
  the bloodstream.

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Common cold

• Rhinoviruses (50)
• Coronaviruses (15-20)
• Rhinoviruses attached to ICAN-1 on nasal mucous

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Infection of he middle ear

• Otitis Media
• S. pneumoniae (35)
• H. influenzae (20-30)
• M. catarrhalis (10-15)
• S. pyogenes (8-10)
• S. aureus (1-2)
• Treated with broad-spectrum antibiotics
• Incidence of S. pneumoniae reduced by vaccine

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Microbial Diseases of the Lower Respiratory System

• Bacteria, viruses, fungi cause
• Bronchitis
• Bronchiolitis
• Pneumonia

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Pertussis (Whooping Cough)

• Bordetella pertussis
• Gram-negative coccobacillus
• Capsule
• Tracheal cytotoxin of cell wall damaged ciliated
  cells
• Pertussis toxin
• Prevented by DTaP vaccine (acellular Pertussis
  cell fragments)
• Stages
• Catarrhal stage, like common cold
• Paroxysmal stage Violent coughing siege
• Convalescence stage

Figure 24.8
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Tuberculosis

• Mycobacterium tuberculosis
• Acid-fast rod.
• Transmitted from human to human
• M. bovis
• Not transmitted from human to human
• M. avium
• Intracellular complex
• infects people with late stage HIV infection
• Treatment of Tuberculosis Prolonged treatment
  with multiple antibiotics
• Vaccines BCG, live, avirulent M. bovis. Not
  widely used in U.S.

Figure 24.9
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Tuberculosis
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Tuberculosis
Diagnosis Tuberculin skin test screening
current or previous infection Followed by X-ray
or CT, acid-fast staining of sputum, culturing
bacteria
Figure 24.11
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Pneumonias

• Pneumonia
• an illness of the lungs and in which the alveoli
  (microscopic air-filled sacs of the lung
  responsible for absorbing oxygen) become inflamed
  and flooded with fluid.
• Pneumonia can result from a variety of causes
  bacteria, viruses, fungi or parasites
• Typical pneumonia is caused by S. pneumoniae.
• Atypical pneumonias are caused by other
  microorganisms.
• Typical symptoms
• cough,
• chest pain,
• fiver,
• breathing difficulty,
• rust-colored sputum.
• Diagnostic tools include x-rays and examination
  of the sputum.
• Treatment depends on the cause of pneumonia
  bacterial pneumonia is treated with antibiotics.

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Pneumomoccal Pneumonia

• Streptococcus pneumoniae
• Gram-positive encapsulated diplococci
• Diagnosis by culturing bacteria
• Penicillin is drug of choice

Figure 24.13
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Pneumonia

• Haemophilus influenzae
• Gram-negative coccobacillus
• Alcoholism, poor nutrition, cancer, or diabetes
  are predisposing factors
• Second-generation cephalosporins
• Mycoplasma pneumoniae
• It is an endemic disease.
• Diagnosis is by PCR or serological tests.
• Legionella pneumophila
• Aerobic gram-negative rod.
• The bacterium can grow in water
• such as air-conditioning cooling towers,
• and then be disseminated in the air.
• This pneumonia does not appear to be transmitted
  from person to person.
• Bacterial culture, FA tests, and DNA probes are
  used for laboratory diagnosis.

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Obligate intracellular pathogens

• Chlamydophila pneumoniae
• has a complex life cycle and must infect another
  cell in order to reproduce.
• It is transmitted from person to person.
• Tetracycline is used for treatment.
• Coxiella burnetii causes Q fever.
• The disease is usually transmitted to humans
  through unpasteurized milk or inhalation of
  aerosols in dairy barns.
• Laboratory diagnosis is made with the culture of
  bacteria in embryonated eggs or cell culture.

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Melioidosis

• Burkholderia pseudomallei
• Gram-negative, rod-shaped
• bipolar,
• aerobic,
• motile
• A human and animal pathogen
• Transmitted by inhalation, ingestion, or through
  puncture wounds.
• Symptoms include pneumonia, sepsis, and
  encephalitis

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Viral Pneumonia

• Viral pneumonia as a complication of influenza,
  measles, chickenpox
• Viral etiology suspected if no cause determined
• Respiratory Syncytial Virus (RSV)
• Common in infants 4500 deaths annually
• Causes cell fusion (syncytium) in cell culture
• Symptoms coughing
• Diagnosis by serologic test for viruses and
  antibodies
• Treatment Ribavirin

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Influenza

• Influenza virus
• Hemagglutinin (H) spikes
• used for attachment to host cells
• Neuraminidase (N) spikes
• used to release virus from cell
• Antigenic shift
• Changes in H and N spikes
• Probably due to genetic recombination between
  different strains infecting the same cell
• Antigenic drift
• Mutations in genes encoding H or N spikes
• May involve only 1 amino acid
• Allows virus to avoid mucosal IgA antibodies
• Influenza serotypes
• A causes most epidemics, H3N2, H1N1, H2N2
• B moderate, local outbreaks
• C mild disease
• Chills, fever, headache, muscle aches (no
  intestinal symptoms)
• 1 mortality due to secondary bacterial
  infections
• Treatment Amantadine

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Fungal Diseases of the Lower Respiratory System

• Fungal spores are easily inhaled
• They may germinate in the lower respiratory
  tract.
• The incidence of fungal diseases has been
  increasing in recent years.
• The mycoses in the sections below can be treated
  with amphotericin B.

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Fungal Diseases of the Lower Respiratory System

• Histoplasmosis
• Histoplasma capsulatum
• subclinical respiratory infection that only
  occasionally progresses to a severe, generalized
  disease.
• Coccidioidomycosis
•  Coccidioides immitis -
• Most cases are subclinical,
• tuberculosis can result.
• Pneumocystis Pneumonia 
• Pneumocystis jiroveci is found in healthy human
  lungs,
• causes disease in immunosuppressed patients.
• Opportunistic fungi can cause respiratory disease
  in immunosuppressed hosts, especially when large
  numbers of spores are inhaled - Aspergillus,
  Rhizopus, and Mucor.

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Learning objectives

• Describe how microorganisms are prevented from
  entering the respiratory system.
• Characterize the normal microbiota of the upper
  and lower respiratory systems.
• Differentiate among pharyngitis, laryngitis,
  tonsillitis, sinusitis, and epiglottitis.
• List the causative agent, symptoms, prevention,
  preferred treatment, and laboratory
  identification tests for streptococcal
  pharyngitis, scarlet fever, diphtheria, cutaneous
  diphtheria, and otitis media.
• List the causative agents and treatments for the
  common cold.
• List the causative agent, symptoms, prevention,
  preferred treatment, and laboratory
  identification tests for pertussis and
  tuberculosis.
• Compare and contrast the seven bacterial
  pneumonias discussed in this chapter.
• List the etiology, method of transmission, and
  symptoms of melioidosis.
• List the causative agent, symptoms, prevention,
  and preferred treatment for viral pneumonia, RSV,
  and influenza.
• List the causative agent, mode of transmission,
  preferred treatment, and laboratory
  identification tests for four fungal diseases of
  the respiratory system.