Notes Unit 16
Airborne Diseases
Structure and Function of the Respiratory System
The respiratory system is composed of two divisions: the upper respiratory system, and the lower respiratory
system.
 Upper respiratory system = nose, throat, middle ear. Defenses against pathogens include: coarse hairs
in the nose that filter dust particles from the air, mucous membrane in the nose which contains mucussecreting cells and cilia (small hairs), mucous membranes in the throat which are moist and trap dust and
some microorganisms. Tonsils contribute to immunity to certain infections. There are quite a few
organisms that are considered normal flora in this part of our respiratory system.
 Lower respiratory system = larynx (voice box), trachea (wind pipe), bronchial tubes, alveoli (in lungs).
Defenses against pathogens include: ciliated mucous membranes. Antibodies are also secreted at this
level to provide defense. No normal flora; mostly sterile.
Structures of Upper Respiratory System
**DPT Vaccine: Diphtheria, Pertussis, Tetanus
**MMR Vaccine: Measles, Mumps, Rubella
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Structures of the Lower Respiratory System
Important Diseases
1. Diphtheria
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Corynebacterium diphtheriae
Bacteria - Gram positive rod, club shaped
Produces a diphtheria toxin which interferes with protein synthesis – only 0.01
mg of this toxin is enough to kill a 200 lb. person.
Sore throat, fever, general malaise, swelling of neck. A tough grayish membrane
forms in the throat in response to the infection containing fibrin, dead tissue, and
bacterial cells. This membrane can block the passage of air to the lungs.
Grayish membrane closing off throat
Direct person- to-person transmission by intimate respiratory and physical
contact.
Antibiotics plus an antitoxin. Children are also immunized against this disease in
the DPT (diphtheria-pertussis-tetanus) shot.
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2. Pertussis (Whooping Cough)
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Bordetella pertussis
Bacteria - Gram negative coccobacillus
Possesses a capsule around body; produces several toxins: tracheal cytotoxin
damages cilia in respiratory tract; pertussis toxin enters bloodstream and causes
symptoms of disease.
Begins with symptoms of common cold in first stage. In second stage, after
tracheal cytotoxin works, mucus begins to accumulate in the throat, and person
desperately attempts to cough up the mucus, but can’t. Violent coughing can
cause broken ribs, and gasp for air between coughs. May take months to get rid
of, and can cause brain damage due to lack of oxygen.
Violent coughing in children
Inhalation of droplets from another person
Antibiotics. Children are vaccinated against in the DPT vaccine.
3. Strep Throat
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Group A Streptococcus pyogenes
Bacteria - Gram positive cocci in chains
This group of bacteria is able to produce special enzymes called streptokinases,
which break up fibrin clots, and streptolysins, which kill red blood cells, tissue
cells, and some white blood cells.
Local inflammation of throat, fever, tonsillitis, swollen lymph nodes in neck, can
cause ear infections too, red throat with streaks in it. If don’t treat, could develop
rheumatic fever.
Red throat with streaks
By respiratory secretions
Antibiotics
4. Bacterial Meningitis
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Many can cause, but the three most common are Streptococcus pneumoniae,
Haemophilus influenzae, and Neisseria meningitidis
Bacteria (can be caused by viruses also, but not as severe)
Possess a capsule which helps them from being phagocytized
High fever, headache, and stiff neck are common symptoms of meningitis in
anyone over the age of 2 years. These symptoms can develop over several hours,
or they may take 1 to 2 days. Other symptoms may include nausea, vomiting,
discomfort looking into bright lights, confusion, and sleepiness. In newborns and
small infants, the classic symptoms of fever, headache, and neck stiffness may be
absent or difficult to detect, and the infant may only appear slow or inactive, or be
irritable, have vomiting, or be feeding poorly. As the disease progresses, patients
of any age may have seizures.
Spinal cord infection – headache, neck stiffness. Usually affects people that are
in close quarters such as schools, day cares, colleges, etc.
The bacteria are spread through the exchange of respiratory and throat secretions
(i.e., coughing, kissing).
Antibiotics
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5. Legionnaire’s Disease
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Legionella pneumophilia
Bacteria - Gram negative rod
Bacteria live in water and are very resistant to chlorine
Signs of the disease can include: a high fever, chills, and a cough. Some people
may also suffer from muscle aches and headaches. Chest X-rays are needed to
find the pneumonia caused by the bacteria, and other tests can be done on sputum
(phlegm), as well as blood or urine to find evidence of the bacteria in the body.
Breathing in water from infected water supply in a building.
Inhalation of droplets from infected water supply (not person to person). Water
such as that in air conditioning cooling towers, whirlpool spas, humidifiers,
showers, fountains, etc. inside buildings.
Antibiotics.
6. Tuberculosis (TB)
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Mycobacterium tuberculosis
Bacteria - slender rod (does not stain by Gram stain; must use acid-fast stain)
The host reacts to this bacteria by creating a walled-off lesion called a tubercle
(meaning lump). The lesion heals, becoming calcified, which clearly shows up on
x-rays. Then the tubercle breaks down, and releases the bacteria into the airways
of the lungs, and eventually the cardiovascular and lymphatic systems.
The general symptoms of TB disease include feelings of sickness or weakness,
weight loss, fever, and night sweats. Also includes coughing, chest pain, and the
coughing up of blood. TB usually affects the lungs, but it can also affect other
parts of the body, such as the brain, the kidneys, or the spine
Tubercles on the lungs when x-rayed; coughing.
Inhalation of droplets from an infected person
A multiple-drug regimen. Also chemotherapy. Long-term treatment (months).
7. Tularemia
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Francisella tularensis
Bacteria; Gram-negative rod
As few as 10 bacteria introduced into a wound can cause disease; can survive for
long periods inside white blood cells. Great bioweapon.
Between 3-5 days after exposure, symptoms of tularemia could include sudden
fever, chills, headaches, diarrhea, muscle aches, joint pain, dry cough, progressive
weakness. People can also catch pneumonia and develop chest pain, bloody
sputum and can have trouble breathing and even sometimes stop breathing. Other
symptoms of tularemia depend on how a person was exposed to the tularemia
bacteria. These symptoms can include ulcers on the skin or mouth, swollen and
painful lymph glands, swollen and painful eyes, and a sore throat.
Sore on skin from a rabbit (or sometimes a rodent).
People can get tularemia many different ways: being bitten by an infected tick,
deerfly or other insect, handling infected animal carcasses, eating or drinking
contaminated food or water, or breathing in the bacteria.
Antibiotics for prolonged periods of time.
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8. Influenza
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Influenza Virus (many different strains)
Virus
Virus contains H spikes, which allow the virus to recognize and attach to body
cells, and N spikes, which allow the virus to leave the host cell after replication.
Can mutate rapidly to avoid detection by the body.
Symptoms of flu include fever, headache, extreme tiredness, dry cough, sore
throat, runny or stuffy nose, and muscle aches. Children can have additional
gastrointestinal symptoms, such as nausea, vomiting, and diarrhea, but these
symptoms are uncommon in adults. Although the term "stomach flu" is
sometimes used to describe vomiting, nausea, or diarrhea, these illnesses are
caused by certain other viruses, bacteria, or possibly parasites, and are rarely
related to influenza. Some of the complications caused by flu include bacterial
pneumonia, dehydration, and worsening of chronic medical conditions, such as
congestive heart failure, asthma, or diabetes. Children may get sinus problems and
ear infections as complications from the flu.
Cold-like symptoms with muscle aches. Lower respiratory system disease.
The main way that influenza viruses are spread is from person to person in
respiratory droplets of coughs and sneezes. Can also get from touching something
a flu victim has touched.
None – can only manage symptoms. Vaccines against some strains are available.
9. Common Cold
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Rhinoviruses, Coronaviruses are most common (and 200 others). Called “human
parainfluenza viruses.”
Viruses
It is estimated that a single Rhinovirus is sufficient to cause a cold!
Sneezing, excessive nasal secretion, congestion
Normal symptoms are the hallmark; seasonal
Spread from respiratory secretions through close contact with infected persons or
contact with contaminated surfaces or objects
None – just manage symptoms
10. Respiratory Syncytial Virus (RSV)
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
RSV
Virus
Affects mostly infants under 2 years of age; almost all children will be infected by
their 2nd birthday.
Illness usually begins 4 to 6 days after exposure (range: 2 to 8 days) with a runny
nose and decrease in appetite. Coughing, sneezing, and fever typically develop 1
to 3 days later. Wheezing may also occur. In very young infants, irritability,
decreased activity, and breathing difficulties may be the only symptoms of
infection. Most otherwise healthy infants infected with RSV do not require
hospitalization. In most cases, including among those who need to be
hospitalized, full recovery from illness occurs in about 1 to 2 weeks.
Pneumonia-like symptoms in children less than 1 year of age.
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Transmission:
Treatment:
Spread from respiratory secretions through close contact with infected persons or
contact with contaminated surfaces or objects.
None – can only manage symptoms. Frequent handwashing and wiping of hard
surfaces with soap and water or disinfectant may help stop infection and spread of
RSV. Also, persons with RSV illness should not share cups or eating utensils with
others.
11. Measles (Rubeola)
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Rubeola virus
Virus
Many complications can result from measles – in approx. 20% of cases.
Symptoms begin to appear about 10 to 12 days after exposure to the virus. The
infected person first experiences a fever lasting about 2 to 4 days that can peak as
high as 103 degrees F to 105 degrees F. This is followed by the onset of cough,
runny nose, and/or conjunctivitis (pink eye). The rash usually appears about 14
days after exposure and lasts 5 to 6 days. It begins at the hairline, then involves
the face and upper neck. Over the next 3 days, the rash gradually proceeds
downward and outward, reaching the hands and feet. Lesions called Koplik’s
spots also appear in the mouth, and this is how measles are diagnosed.
Complications include diarrhea, ear infections, pneumonia, encephalitis, seizures,
and death
Body rash with Koplik’s spots in mouth.
The virus resides in the mucus in the nose and throat of the infected person. When
that person sneezes or coughs, droplets spray into the air. The infected mucus can
land in other people’s noses or throats when they breathe or put their fingers in
their mouth or nose after handling an infected surface. The virus remains active
and contagious on infected surfaces for up to 2 hours. Measles spreads so easily
that anyone who is not immunized will probably get it. The virus grows in the
cells that line the back of the throat and in lung cells.
None – vaccine only. (This is given to all children in the MMR vaccine, which
stands for measles, mumps and rubella)
12. Mumps
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Mumps virus
Virus
None.
Fever, headache, muscle aches, tiredness, and loss of appetite; followed by
swelling of salivary glands. The parotid salivary glands (which are located within
your cheek, near your jaw line, below your ears) are most frequently affected.
Swelling of parotid glands. Severe complications are rare. However, mumps can
cause: inflammation of the brain and/or tissue covering the brain and spinal cord
(encephalitis/meningitis), inflammation of the testicles (orchitis), inflammation of
the ovaries and/or breasts (oophoritis and mastitis), spontaneous abortion,
deafness, usually permanent
The mumps virus replicates in the upper respiratory tract and is spread through
direct contact with respiratory secretions or saliva or through fomites.
None. MMR vaccine.
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13. Rubella (German measles)
Causative Organism: Rubella virus
Type of Organism: Virus
Pathogenicity:
Birth defects if acquired by a pregnant woman: deafness, cataracts, heart defects,
mental retardation, and liver and spleen damage (at least a 20% chance of damage
to the fetus if a woman is infected early in pregnancy)
Symptoms:
Rash of small red spots and a light fever; complications rare. Lasts 2-3 days.
Transmission:
Respiratory route – coughing and sneezing.
Treatment:
None – vaccine only. (This is given to all children in the MMR vaccine)
14. Chickenpox
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Varicella-zoster virus
Virus
Remains latent in the body; can come back later as shingles as an adult.
A skin rash of blister-like lesions, covering the body but usually more
concentrated on the face, scalp, and trunk. Most, but not all, infected individuals
have fever, which develops just before or when the rash appears. If exposed,
persons who have been vaccinated against the disease may get a milder illness,
with less severe rash (sometimes involving only a few red bumps that look similar
to insect bites) and mild or no fever. Complications can include bacterial infection
of the skin, swelling of the brain, and pneumonia. Adolescents and adults are
more at risk for severe disease.
Blister-like rash in children under 15.
Spread by coughing and sneezing (highly contagious), by direct contact, and by
aerosolization of virus from skin lesions.
There is a vaccine available to prevent.
15. Shingles
Causative Organism: Herpes zoster virus (same virus as chickenpox)
Type of Organism: Virus
Pathogenicity:
After having chicken pox, it lives in nervous system only to re-emerge one day in
the form of shingles.
Symptoms:
Shingles usually starts as a rash on one side of the face or body. The rash starts as
blisters that scab after 3 to 5 days. The rash usually clears within 2 to 4 weeks.
Before the rash develops, there is often pain, itching, or tingling in the area where
the rash will develop. Other symptoms of shingles can include fever, headache,
chills, and upset stomach. Shingles most commonly occurs in people 50 years old
and older. Very rarely, shingles can lead to pneumonia, hearing problems,
blindness, brain inflammation (encephalitis) or death. For about 1 person in 5,
severe pain can continue even after the rash clears up. This pain is called postherpetic neuralgia. As people get older, they are more likely to develop postherpetic neuralgia, and it is more likely to be severe.
Hallmark:
Blister-like rash in older people, usually around trunk of body.
Transmission:
Shingles cannot be passed from one person to another. However, the virus that
causes shingles, VZV, can be spread from a person with active shingles to a
person who has never had chickenpox through direct contact with the rash. The
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Treatment:
person exposed would develop chickenpox, not shingles. The virus is not spread
through sneezing, coughing or casual contact. A person with shingles can spread
the disease when the rash is in the blister-phase. Once the rash has developed
crusts, the person is no longer contagious. A person is not infectious before
blisters appear or with post-herpetic neuralgia (pain after the rash is gone).
There are medicines available to shorten the duration of disease, but no cure.
16. Hantavirus Pulmonary Syndrome
Causative Organism:
Types of Organisms:
Pathogenicity:
Symptoms:
Hallmark:
Transmission:
Treatment:
Hantavirus
Virus
Can affect even healthy individuals.
Early symptoms include fatigue, fever and muscle aches, especially in the large
muscle groups-thighs, hips, back, and sometimes shoulders. These symptoms are
universal. There may also be headaches, dizziness, chills, and abdominal
problems, such as nausea, vomiting, diarrhea, and abdominal pain. About half of
all HPS patients experience these symptoms. Four to 10 days after the initial
phase of illness, the late symptoms of HPS appear. These include coughing and
shortness of breath, with the sensation of, as one survivor put it, a "...tight band
around my chest and a pillow over my face" as the lungs fill with fluid.
Pulmonary disease caused by breathing in deer mouse excretions.
By infected deer mouse; breathing in aerosolized urine, droppings, or saliva.
None, just supportive care.
17. Smallpox
Causative Organism:
Type of Organism:
Pathogenicity:
Symptoms:
Variola virus(there is a major and a minor form)
Virus
There are two clinical forms of smallpox. Variola major is the severe and most
common form of smallpox, with a more extensive rash and higher fever. There
are four types of variola major smallpox: ordinary (the most frequent type,
accounting for 90% or more of cases); modified (mild and occurring in previously
vaccinated persons); flat; and hemorrhagic (both rare and very severe).
Historically, variola major has an overall fatality rate of about 30%; however, flat
and hemorrhagic smallpox usually are fatal. Variola minor is a less common
presentation of smallpox, and a much less severe disease, with death rates
historically of 1% or less.
The first symptoms of smallpox include fever, malaise, head and body aches, and
sometimes vomiting. The fever is usually high, in the range of 101 to 104 degrees
Fahrenheit. At this time, people are usually too sick to carry on their normal
activities. This is called the prodrome phase and may last for 2 to 4 days. A rash
emerges first as small red spots on the tongue and in the mouth. These spots
develop into sores that break open and spread large amounts of the virus into the
mouth and throat. At this time, the person becomes most contagious. Around the
time the sores in the mouth break down, a rash appears on the skin, starting on the
face and spreading to the arms and legs and then to the hands and feet. Usually
the rash spreads to all parts of the body within 24 hours. As the rash appears, the
fever usually falls and the person may start to feel better. By the third day of the
rash, the rash becomes raised bumps. By the fourth day, the bumps fill with a
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Hallmark:
Transmission:
Treatment:
thick, opaque fluid and often have a depression in the center that looks like a
bellybutton. (This is a major distinguishing characteristic of smallpox.) Fever
often will rise again at this time and remain high until scabs form over the bumps.
The bumps become pustules—sharply raised, usually round and firm to the touch
as if there’s a small round object under the skin. People often say the bumps feel
like BB pellets embedded in the skin. The pustules begin to form a crust and then
scab. By the end of the second week after the rash appears, most of the sores have
scabbed over.
Raised pustules all over body.
Smallpox normally spreads from contact with infected persons. Generally, direct
and fairly prolonged face-to-face contact is required to spread smallpox from one
person to another. Smallpox also can be spread through direct contact with
infected bodily fluids or contaminated objects such as bedding or clothing.
No cure; but can be vaccinated against to prevent. Smallpox was supposedly
eradicated from the world in 1977.
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