Many years ago, individuals became hysterical whenever anyone in the
neighborhood contracted diseases like poliomyelitis or smallpox. Children were not
allowed to leave their homes for fear of contracting these diseases. Today, however,
we do not fear these diseases because of our knowledge of the benefits of
immunization. Although you may not have appreciated it as a child, those "shots" you
received from the doctor enabled you to resist many childhood diseases. As a Service
Member, immunizations you received on a regular basis or received before entering a
specific overseas area kept you free from disease and enabled you to accomplish the
a. Species Resistance. Species resistance is the ability of a particular species
to resist the disease of another species and is physiological in nature. It has been
observed that warm-blooded animals rarely exhibit microbial diseases associated with
cold-blooded animals. One example of this species resistance is demonstrated by
distemper, an often fatal disease in dogs, which rarely, if ever, affects man.
b. Racial Resistance. Racial resistance means that some races of people are
less susceptible to some diseases than other races. Racial resistance is affected by
heredity, customs, hygiene, and survival rates. An example is that blacks in West Africa
are likely to have a deficiency of the enzyme G6PD. These individuals also have a
resistance to falciparum malaria.
c. Individual Resistance. Many of us have individual resistance, another type
of natural resistance to disease. Some individuals resist colds, flu, and other diseases
to a greater degree than others. Some factors that contribute to this phenomenon are
personal hygiene, state of nutrition, and of course, exposure to pathogenic organisms.
a. Acquired Resistance. Acquired resistance is the ability of the body to
overcome specific diseases or disorders after prior contact with the causative agent. An
antigen is a foreign substance to the body that may be composed of lipid, protein, or
carbohydrate material. Antibodies are specific substances formed by the body in
response to stimulation by antigens. Antibodies are formed by plasma cells.
b. Primary Response. The first time an antigen enters the body, it initiates the
production of a small number of antibodies. This is called the primary response.