Principles of Epidemiology and Microbiology
Lesson
1: Introduction to Disease Transmission and Epidemiology
1-4
1-4. COMMUNICABLE DISEASES
Although not all diseases of military importance are communicable, this lesson will focus upon the communicable diseases-those that can be transmitted from person to person or from an animal to a person. These diseases may be classified into five groups, based upon the manner in which they are spread, the area of the body that they affect, and the type of control needed to prevent their spread.
a. Intestinal Diseases. These diseases are usually transmitted by food or water that has become contaminated with feces from an infected human or animal. Examples are typhoid and paratyphoid fevers, dysentery, and cholera.
b. Respiratory Diseases. These diseases are usually transmitted from person to person by discharges from the nose, mouth, throat, or lungs of an infected person. Examples are the common cold, influenza, pneumonia, streptococcal sore throat, and tuberculosis.
c. Sexually Transmitted Diseases. These diseases are transmitted from person to person by sexual intercourse. Examples are syphilis, gonorrhea, herpes, hepatitis B, and chancroid.
d. Arthropod-Borne Diseases. These diseases are transmitted from person to person or from animal to person by insects or other arthropods. Examples are malaria, typhus, and yellow fever.
e. Miscellaneous Diseases. This group includes those communicable diseases that do not fall into any of the above groups. Examples are rabies (hydrophobia), tetanus (lockjaw), and dermatophytosis (athlete's foot).
