tissue and may have invaded along the lymphatics or the bloodstream. The infectious
agents not only multiply rapidly and invade adjacent tissue, but they also give off
poisonous products called toxins.
(1) Surface. Local infection confined to immediate tissue of the wound is
considered to be surface infection.
(2)
Regional. Infection that spreads along the lymphatics is considered as
regional.
(3)
Systemic. If the invasion is by way of the bloodstream, it is systemic
infection.
1-4.
COMMUNICABLE DISEASES
A communicable disease is an illness that can be transmitted from one person to
another person, from an animal to a person, or from a person to an animal.
Communicable diseases can be divided into the following five groups.
a. Respiratory Diseases. Respiratory diseases are usually transmitted from
person to person by discharges from the nose, mouth, throat, or lungs of an infected
person. Examples of communicable respiratory diseases include the common cold,
influenza (flu), pneumonia, streptococcal throat infection (strep), and tuberculosis (TB).
b. Intestinal Diseases. Intestinal diseases are usually transmitted by food or
water that is contaminated by the feces or urine of an infected person or animal.
Examples of communicable intestinal diseases include typhoid, cholera, and dysentery.
c. Insect-Borne Diseases. Insect-borne diseases are transmitted from a
person to another person or from an animal to a person by insects. Examples of
communicable insect-borne diseases include malaria (transmitted by mosquitoes),
yellow fever (transmitted by mosquitoes), typhus (transmitted by lice), Rocky Mountain
spotted fever (transmitted by ticks), and plague (transmitted by fleas). Ticks and mites
are not true insects, but are generally called insects because of their resemblance to
true insects.
d. Sexually Transmitted Diseases. These diseases are usually transmitted
from person to person by sexual intercourse. Examples include syphilis, gonorrhea
(clap), and chancroid.
e. Bloodborne Diseases. For more on such diseases as human
immunodeficiency virus (HIV) and hepatitis B virus (HBV) and how to protect yourself
against them, see Section III of this lesson.
MD0540
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