Notes Unit



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 mucus-secreting 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

[pic]

**DPT Vaccine: Diphtheria, Pertussis, Tetanus **MMR Vaccine: Measles, Mumps, Rubella

Structures of the Lower Respiratory System

[pic]

Important Diseases

1. Diphtheria

Causative Organism: Corynebacterium diphtheriae

Type of Organism: Bacteria - Gram positive rod, club shaped

Pathogenicity: Produces a diphtheria toxin which interferes with protein synthesis – only 0.01 mg of this toxin is enough to kill a 200 lb. person.

Symptoms: 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.

Hallmark: Grayish membrane closing off throat

Transmission: Direct person- to-person transmission by intimate respiratory and physical

contact.

Treatment: Antibiotics plus an antitoxin. Children are also immunized against this disease in

the DPT (diphtheria-pertussis-tetanus) shot.

2. Pertussis (Whooping Cough)

Causative Organism: Bordetella pertussis

Type of Organism: Bacteria - Gram negative coccobacillus

Pathogenicity: Possesses a capsule around body; produces several toxins: tracheal cytotoxin damages cilia in respiratory tract; pertussis toxin enters bloodstream and causes symptoms of disease.

Symptoms: 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.

Hallmark: Violent coughing in children

Transmission: Inhalation of droplets from another person

Treatment: Antibiotics. Children are vaccinated against in the DPT vaccine.

3. Strep Throat

Causative Organism: Group A Streptococcus pyogenes

Type of Organism: Bacteria - Gram positive cocci in chains

Pathogenicity: 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.

Symptoms: 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.

Hallmark: Red throat with streaks

Transmission: By respiratory secretions

Treatment: Antibiotics

4. Bacterial Meningitis

Causative Organism: Many can cause, but the three most common are Streptococcus pneumoniae,

Haemophilus influenzae, and Neisseria meningitidis

Type of Organism: Bacteria (can be caused by viruses also, but not as severe)

Pathogenicity: Possess a capsule which helps them from being phagocytized

Symptoms: 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.

Hallmark: Spinal cord infection – headache, neck stiffness. Usually affects people that are in close quarters such as schools, day cares, colleges, etc.

Transmission: The bacteria are spread through the exchange of respiratory and throat secretions (i.e., coughing, kissing).

Treatment: Antibiotics

5. Legionnaire’s Disease

Causative Organism: Legionella pneumophilia

Type of Organism: Bacteria - Gram negative rod

Pathogenicity: Bacteria live in water and are very resistant to chlorine

Symptoms: 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.

Hallmark: Breathing in water from infected water supply in a building.

Transmission: 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.

Treatment: Antibiotics.

6. Tuberculosis (TB)

Causative Organism: Mycobacterium tuberculosis

Type of Organism: Bacteria - slender rod (does not stain by Gram stain; must use acid-fast stain)

Pathogenicity: 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.

Symptoms: 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

Hallmark: Tubercles on the lungs when x-rayed; coughing.

Transmission: Inhalation of droplets from an infected person

Treatment: A multiple-drug regimen. Also chemotherapy. Long-term treatment (months).

7. Tularemia

Causative Organism: Francisella tularensis

Type of Organism: Bacteria; Gram-negative rod

Pathogenicity: As few as 10 bacteria introduced into a wound can cause disease; can survive for long periods inside white blood cells. Great bioweapon.

Symptoms: 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.

Hallmark: Sore on skin from a rabbit (or sometimes a rodent).

Transmission: 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.

Treatment: Antibiotics for prolonged periods of time.

8. Influenza

Causative Organism: Influenza Virus (many different strains)

Type of Organism: Virus

Pathogenicity: 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: 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.

Hallmark: Cold-like symptoms with muscle aches. Lower respiratory system disease.

Transmission: 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.

Treatment: None – can only manage symptoms. Vaccines against some strains are available.

9. Common Cold

Causative Organism: Rhinoviruses, Coronaviruses are most common (and 200 others). Called “human parainfluenza viruses.”

Type of Organism: Viruses

Pathogenicity: It is estimated that a single Rhinovirus is sufficient to cause a cold!

Symptoms: Sneezing, excessive nasal secretion, congestion

Hallmark: Normal symptoms are the hallmark; seasonal

Transmission: Spread from respiratory secretions through close contact with infected persons or

contact with contaminated surfaces or objects

Treatment: None – just manage symptoms

10. Respiratory Syncytial Virus (RSV)

Causative Organism: RSV

Type of Organism: Virus

Pathogenicity: Affects mostly infants under 2 years of age; almost all children will be infected by their 2nd birthday.

Symptoms: 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.

Hallmark: Pneumonia-like symptoms in children less than 1 year of age.

Transmission: Spread from respiratory secretions through close contact with infected persons or contact with contaminated surfaces or objects.

Treatment: 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: Rubeola virus

Type of Organism: Virus

Pathogenicity: Many complications can result from measles – in approx. 20% of cases.

Symptoms: 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

Hallmark: Body rash with Koplik’s spots in mouth.

Transmission: 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.

Treatment: None – vaccine only. (This is given to all children in the MMR vaccine, which stands for measles, mumps and rubella)

12. Mumps

Causative Organism: Mumps virus

Type of Organism: Virus

Pathogenicity: None.

Symptoms: 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.

Hallmark: 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

Transmission: The mumps virus replicates in the upper respiratory tract and is spread through direct contact with respiratory secretions or saliva or through fomites.

Treatment: None. MMR vaccine.

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: Varicella-zoster virus

Type of Organism: Virus

Pathogenicity: Remains latent in the body; can come back later as shingles as an adult.

Symptoms: 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.

Hallmark: Blister-like rash in children under 15.

Transmission: Spread by coughing and sneezing (highly contagious), by direct contact, and by aerosolization of virus from skin lesions.

Treatment: 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 post-herpetic neuralgia. As people get older, they are more likely to develop post-herpetic 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 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).

Treatment: There are medicines available to shorten the duration of disease, but no cure.

16. Hantavirus Pulmonary Syndrome

Causative Organism: Hantavirus

Types of Organisms: Virus

Pathogenicity: Can affect even healthy individuals.

Symptoms: 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.

Hallmark: Pulmonary disease caused by breathing in deer mouse excretions.

Transmission: By infected deer mouse; breathing in aerosolized urine, droppings, or saliva.

Treatment: None, just supportive care.

17. Smallpox

Causative Organism: Variola virus(there is a major and a minor form)

Type of Organism: Virus

Pathogenicity: 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.

Symptoms: 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 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.

Hallmark: Raised pustules all over body.

Transmission: 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.

Treatment: No cure; but can be vaccinated against to prevent. Smallpox was supposedly eradicated from the world in 1977.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download