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Epidemiology and Conditions Leading to Parasitic Infestations 21

Source: Centers for Disease Control and Prevention (CDC)

FIGURE 2-7 Human intestine is a perfect environment
for intestinal parasites

build-up of toxins in the body that have been released
from the metabolism of the parasites (Figure 2-7). The
nose is intended for acting as a filter and air conditioner
during respiration, by picking up oxygen and exhaling
carbon dioxide. By filtering the air with nasal hairs, while
warming and moistening the air that is breathed, the in-
terior of the body is able to avoid many of the harmful
products found in the atmosphere including pathogens. Source: Centers for Disease Control and Prevention (CDC)
Problems associated with the nose may include
sinusitis, an inflammation of the sinuses, along with na-
sal polyps and tumors that may cause restrictions in the
nasal passage and further hinder the amount of oxygen
inhaled. All of the conditions may be responsible for aid-
ing in the contraction of a parasitic infection. Ironically,
FIGURE 2-8 Crowded and poor living conditions
parasites often take advantage of certain medical condi-
lead to parasitosis
tions in order to gain a toehold in the body, and then the
parasites themselves cause a deterioration of the physical
condition of the human body, opening the person to more
the more advanced areas of the world may not be equipped
infections that include bacterial and viral infections.
to recognize the signs and symptoms of parasitic infections
they may encounter in the developed countries.
HOW PARASITES ARE Crowded living conditions, contact with infected
COMMONLY CONTRACTED persons and infected animals, or exposure to vectors and
to unsanitary conditions are the most common condi-
Dogs, cats, domestic animals, fowl, and insect vectors tions leading to the condition of parasitosis ( Figure 2-8).
such as the mosquito are examples of intermediate hosts, With world travel increasing the possibility of bringing
but some parasites, such as Ascaris lumbricoides, do not parasites to developed countries, the influx of foreign
require an intermediate host. Eliminating the source of visitors continues to create challenges for health care sys-
parasitic infections and improvement of environmental tems. Routine testing procedures still fall short of being
conditions that prevent parasites from reproducing would even reasonably accurate and efficient. It is estimated that
decrease greatly the numbers of infections that occur. with traditional testing for parasites, accuracy of recovery
Many physicians even in more advanced countries are not and identification of even the most common parasites is
aware of the extent of parasitic infections and the preva- perhaps only 20 percent, and is greatly dependent upon
lence of parasite infections. Those trained and educated in the training and diligence practiced by the laboratory