What are airborne illness and disease?

Definition

Airborne diseases

are those diseases transmitted by contaminated droplets in the air.
Common types of airborne disease include the common cold,
the flu (influenza), chickenpox (varicella), and
tuberculosis.

Exposure

Cold and flu. Both the common cold and the flu are highly contagious. They can be spread from person to person when an infected person coughs or sneezes. People can also catch a common cold or the flu by touching an contaminated object (a fomite) that contains the live virus and by then touching their eyes, nose, or their mouth. Other methods of transmission include kissing and sharing food or drinks.

There are certain risk factors that may cause a person to be more susceptible to a cold or flu. Those risk factors include age (young children and adults age sixty-five years and older are more susceptible), a compromised immune system caused by illness or treatment of an illness (such as human immunodeficiency virus [HIV] infection or chemotherapy), living in a residential care facility, or working in health care.

Chickenpox. Chickenpox is also highly contagious and can be spread from person to person when an infected person coughs or sneezes. One of the main symptoms of chickenpox is a rash that eventually blisters. Touching an open blister that is leaking fluid can also lead to the spread of the disease.

As with the cold or flu, there are certain risk factors that may cause a person to be more susceptible to chickenpox. Risk factors for increased susceptibility to chickenpox include not having had chickenpox in the past, not being given the chickenpox vaccine, and spending a lot of time around children.

Tuberculosis. Although tuberculosis is a contagious disease, it does not spread as easily as the common cold, the flu, or chickenpox. It can still be spread from person to person when an infected person coughs or sneezes, but it is most commonly spread when people spend a lot of time together in close quarters, such the home or office. Tuberculosis is not spread by handshaking, kissing, or sharing food or drinks.

In addition to living with or working with someone who has tuberculosis, there are other risk factors that may make someone more susceptible to contracting the disease, including the following: having a compromised immunity, living in a region where there are high rates of tuberculosis, age (sixty-five years and older), long-term drug or alcohol use, living in a residential care facility, and working in health care.

People who are at high risk for contracting tuberculosis, or those who think they may have been exposed to the disease, should be tested for tuberculosis. The following persons should be periodically tested for tuberculosis infection: health care workers, people with HIV or other immune system disorders, people who live in areas with high rates of infection, people who live in residential care facilities, persons who have symptoms of active tuberculosis, people who live or work in correctional facilities, injection-drug users, and persons who have lived with or who have spent much time with someone who has active tuberculosis.

Prevention

Cold. There is currently no vaccination for the prevention of the common cold. The best method of preventing the common cold is frequent handwashing, particularly before eating or preparing food.

Another way to help prevent the common cold is to periodically clean with antibacterial wipes all shared surfaces, such as telephones, computer keyboards, refrigerator handles, doorknobs, and toys. A third method for preventing the common cold is to teach children to drink from their own drinking glass, rather than sharing. A fourth method of common cold prevention is to avoid close contact with people who have a cold or other respiratory tract infection.

Flu. The best way to prevent the flu is to get a flu shot
(influenza
vaccination). In the fall of 2010, the flu vaccine began
protecting against the most common types of flu viruses, seasonal influenza and
the H1N1 virus (swine flu). The Centers for Disease Control and
Prevention (CDC) recommends that all persons age six months and older be
vaccinated, although there are some exceptions. The following people should not
get a flu vaccine without consulting a physician: persons who are allergic to
eggs, who have had a previous allergic reaction to the flu vaccine, who have
Guillain-Barré
syndrome, or who are already sick and who have a fever.
Vaccination is recommended after illness, however.

In addition to vaccination, there are other steps to help prevent the spread of influenza, including frequent handwashing, using a tissue to cover the nose or mouth when coughing or sneezing, periodically cleaning shared surfaces, avoiding close contact with people who have symptoms of a cold or flu, not sharing drinking glasses, and not going to work when sick.

Chickenpox. The best method for preventing chickenpox is the
varicella (chickenpox) vaccine. The CDC recommends that all children and adults
who do not have evidence of immunity to varicella be vaccinated. Evidence of
immunity, according to the CDC, includes documentation of either of the following:
two doses of varicella vaccine, blood tests that show immunity, laboratory
confirmation of prior varicella disease, a diagnosis of chickenpox or verification
of a history of chickenpox from a qualified health care provider, or a diagnosis
of herpes zoster (shingles) or verification of a history of herpes zoster
(shingles) from a qualified health care provider.

Some people are given the chickenpox vaccine after exposure to help prevent them from contracting the disease. According to the CDC, the chickenpox vaccine is not recommended for the following people: those allergic to gelatin, those who have a moderate or serious illness, pregnant women, persons with compromised immune systems because of illness or treatment of illness, persons who have received blood or blood products three to eleven months before considering vaccination, and persons with a family history of immune deficiency.

Tuberculosis. Although a vaccine has been developed for the
prevention of tuberculosis, that vaccine is not commonly used in the United
States. The tuberculosis vaccine, which is known as the Bacille
Calmette-Guérin vaccine, does not always protect against tuberculosis and could
cause a false-positive result in people who are later tested for tuberculosis.

Preventing the spread of tuberculosis is still possible without the vaccine. For example, persons who are infected with tuberculosis can be treated before their disease becomes active. This involves regular testing of people who may be at risk. For persons who test positive for tuberculosis infection, medications that can be prescribed by doctors to help prevent active disease. Other methods of preventing the spread of tuberculosis include covering the nose and mouth with a tissue when coughing or sneezing, opening windows to ventilate rooms if the weather permits, avoiding the workplace when sick, wearing a mask around others, and avoiding close contact with family members for the first few weeks of treatment.

Symptoms

Cold. Symptoms of the common cold begin from one and three days after exposure, and may include runny or stuffy nose, coughing, sneezing, congestion, sore throat, fatigue, and a general feeling of being unwell.

Flu. Flu symptoms are much like symptoms of the common cold, but are more severe. In addition to cold symptoms, persons who have the flu will also experience fever and chills, headache or body aches; other persons, particularly children, also may experience nausea and vomiting. There are potential complications that are related to the common cold or flu. Complications may include ear infection (particularly in small children), sinus infection, bronchitis, and pneumonia.

Chickenpox. The main symptom of chickenpox is a skin rash, mostly
on the face, scalp, chest, and back. The rash eventually blisters, then dries up
and crusts over. Some people may also experience fever, headache, sore throat, and
a general feeling of being unwell.

As with the cold and flu, some people do experience complications that are
related to chickenpox. Complications may include pneumonia, skin infection, and,
in rare cases, encephalitis (infection of the brain). Another complication
of chickenpox may occur many years after a person has the disease. This
complication is shingles, an infection that is characterized by a painful rash. It
is usually seen in older adults and is caused by the same virus that causes
chickenpox.

Tuberculosis. Many people who contract tuberculosis have no symptoms. Persons who are asymptomatic have latent TB (tuberculosis) infection and cannot spread the disease to others unless their disease becomes active.

When tuberculosis bacteria begin actively multiplying in the body, the person who is infected is said to have active TB disease. Symptoms of active TB include a persistent cough (sometimes coughing up blood), chest pain when breathing or coughing, fever, chills, night sweats, fatigue, loss of appetite, and weight loss. People with active TB are contagious and can spread the disease to others.

Complications from tuberculosis can be serious or even fatal. Tuberculosis
complications may include lung damage, joint damage, damage to other organs,
meningitis, and death.

Treatment

Cold. There is no cure for the common cold. Cold “treatments” are designed not to cure the cold but to relieve symptoms. Over-the-counter (OTC) drugs that can help to relieve cold symptoms include nasal sprays, decongestants, and cough medicines. These medications are not recommended for children under the age of two years unless okayed by a physician. People who have the common cold should rest and drink plenty of fluids.

Flu. As with the common cold, the “cure” for the flu is rest, liquids, and symptom relief. OTC decongestants and cough syrups can be used to relieve nasal congestion and cough. OTC pain relievers, such as Tylenol or Advil, can help to relieve headache, body aches, and sore throat.

Some fever can be beneficial because it helps the body fight the virus, so many doctors recommend that fever not be treated unless it is above 102° Fahrenheit, although an exception can be made if the fever is causing a great deal of discomfort. Fever in infants under three months of age can be a sign of a serious infection, so one should seek immediate medical attention.

In some cases, a physician may prescribe antiviral medications, which are also used for symptom reduction rather than as a cure for the flu. Antiviral medications are generally only given to people who are at increased risk of flu complications, such as young children, the elderly, pregnant women, people who are in the hospital, and people who suffer from certain chronic medical conditions.

Antibiotics will not cure the common cold or the flu. They also will not relieve cold or flu symptoms because antibiotics are used to treat bacterial infections, and both the common cold and the flu are viruses.

Chickenpox. Most healthy people do not require medical treatment for chickenpox, but some doctors may prescribe an antihistamine to help relieve itching. Oatmeal baths or calamine lotion can also help to prevent itching.

People who have other health problems or who may be considered at high risk for
complications of chickenpox, may be given antiviral medications or immunoglobulin
treatment. These treatments are intended to lessen the severity of the disease
and, therefore, to prevent complications. OTC pain medications, such as Tylenol or
Advil, can be given to reduce fever, but people with chickenpox should not be
given aspirin because aspirin can cause a serious medical condition called
Reye’s
syndrome.

Tuberculosis. Prescribed medication can prevent TB from becoming active. It can also help cure active TB.

Impact

According to the National Institutes of Health, the United States experiences
more than 1 billion cases of the common cold each year. The World Health
Organization (WHO) estimates that there are between 3 and 5 million cases of
severe influenza illness each year during seasonal epidemics, resulting in between
250,000 and 500,000 deaths. CDC statistics show that during an average flu season,
5 to 20 percent of the U.S. population will get the flu and more than 200,000 will
be hospitalized because of complications of the flu. Since the last decades of the
twentieth century,deaths from influenza in the United States have ranged from a
low of 3,000 to a high of 49,000 persons.

According to the CDC, before the varicella vaccine was developed in 1995, around 4 million cases of chickenpox were reported each year in the United States. Also, there was an average of 10,600 hospitalizations and 100 to 150 deaths. From 1995 to 2005, the incidence of chickenpox declined 90 percent overall. In 2002, hospitalizations from chickenpox had decreased 88 percent from the years 1994 and 1995. Death rates dropped 66 percent between 1990 and 2001.

WHO estimates that one-third of the world’s population is infected with tuberculosis at any given time, and that 5 to 10 percent of those who are infected will develop active TB. In 2009, about 1.7 million people died from tuberculosis.

Bibliography

Centers for Disease Control and Prevention. “Basic TB Facts.” Available at http://www.cdc.gov/tb/topic/basics. A tuberculosis fact sheet that includes information about how tuberculosis is spread and discusses the difference between latent TB and TB disease.

_______. “Seasonal Flu: What to Do if You Get Sick.” Available at http://www.cdc.gov/flu/whattodo.htm. Discusses influenza diagnosis, symptoms, medical treatment, recovery, and emergency warning signs.

Mason, Robert J., et al., eds. Murray and Nadel’s Textbook of Respiratory Medicine. 5th ed. Philadelphia: Saunders/Elsevier, 2010. Details basic anatomy, physiology, pharmacology, pathology, and immunology of the lungs.

Mayo Foundation for Medical Education and Research. “Chickenpox.” Available at http://www.mayoclinic.com/health/chickenpox/DS00053. A detailed description of chickenpox that includes a definition of chickenpox, symptoms, risk factors, complications, prevention, and treatment.

_______. “Common Cold.” Available at http://www.mayoclinic.com/health/common-cold/DS00056. A detailed description of the common cold that includes a definition of the common cold, symptoms, risk factors, complications, prevention, and treatment.

_______. “Tuberculosis.” Available at http://www.mayoclinic.com/health/tuberculosis/DS00372. A detailed description of tuberculosis that includes a definition of tuberculosis, symptoms, risk factors, complications, prevention, and treatment.

MedlinePlus. “Chickenpox.” Available at http://www.nlm.nih.gov/medlineplus/ency/article/001592.htm. An overview of chickenpox, including causes, symptoms, diagnosis, treatment, prevention, prognosis, and possible complications.

U.S. Department of Health and Human Services. “Tuberculosis: Getting Healthy, Staying Healthy.” Available at http://www.niaid.nih.gov/topics/tuberculosis/understanding/documents/tb.pdf. An overview of tuberculosis, including how the disease is spread, how it is diagnosed, and treatment options.