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Limit Contagion
Understanding the elements required for infectious
organisms to spread and taking appropriate precautions
can help prevent illness. By Rear Adm. Joyce Johnson, D.O.
I
nfectious organisms such as vi- water or eat food contaminated with or-
ruses, bacteria, fungi, and parasites are ganisms found in feces (fecal-oral trans-
all around us. They are in the air, soil, mission). HIV/AIDS and hepatitis B and C
and water, on surfaces, and in our food. are transmitted by blood or sexual con-
Most have no impact on humans; some tact. Malaria and West Nile Virus spread
are helpful; and a few are harmful. via mosquito bites.
Three elements are required for an As routes of transmission vary, so do
infectious disease to spread: a pathogenic the ways to interrupt them. Often changes
(disease-causing) organism, a route of in behavior can help — using a tissue to
transmission, and a host (someone to cover a cough or sneeze, drinking safe
Some Face More
catch the disease). If any one of these water, preparing food carefully, avoiding
Risk Than Others
elements is absent, there won’t be a sick contact with blood, practicing safe sex,
■ The elderly, the very patient. Control of infectious disease fo- protecting oneself from mosquito bites,
young, and those with
cuses on trying to break this chain. etcetera. Washing one’s hands is key to
chronic diseases or im-
There are various ways to control interrupting transmission of many infec-
mune problems are more
susceptible to disease.
pathogenic organisms. Those on fresh tious diseases. Still, disease-causing organ-
During outbreaks, they
food, such as fruits and vegetables, often isms often get through to a potential host.
often must take special can be removed by washing or peeling. Fortunately the body has many natural
precautions to break the
Cooking kills organisms and is effective defense mechanisms to prevent infection.
chain of transmission.
with meat and egg products. Milk can be The skin and respiratory system (includ-
pasteurized to kill naturally occurring ing the hairs in the nose) prevent many
bacteria; pasteurization also helps keep organisms from entering the body. Acid
milk from spoiling. in the stomach also plays a preventive
Organisms on surfaces can be con- role. Humans possess a robust immune
trolled with disinfectants. In a health care system that can develop antibodies tai-
setting, a 1:10 solution of chlorine bleach lored to fi ght specifi c organisms. Vaccines
and water commonly is used to clean after have been developed to help fi ght many
blood contamination. Hospitals use au- diseases such as the fl u, polio, measles,
toclaves to sterilize supplies and surgical mumps, and chicken pox. Prophylactic
linens by heating them to a very high tem- medications can prevent some diseases,
perature, thereby killing organisms. such as malaria. MO
Routes of transmission vary from one
organism to another. Infl uenza and other
— Rear Adm. Joyce Johnson, USPHS-Ret.,
respiratory diseases can be transmitted
D.O., M.A., is vice president, Health Sciences,
Battelle Memorial Institute, Arlington, Va. Find
through the air when someone next to
more health and wellness resources at www
you coughs or sneezes. Many diarrheal
.moaa.org/wellness. For submission information,
diseases are spread when people drink see page 18.
42 MILITARY OFFICER JULY 2009 PHOTO: STEVE BARRETT
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dr.indd 42 66/3/09 2:40:43 PM/3/09 2:40:43 PM
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