Page 49 - parasitology for medical and clinical laboratoryprofessionals

Epidemiology and Conditions Leading to Parasitic Infestations 29

TABLE 2-2 Anatomical Features Contributing to the Identification of Intestinal Parasites (continued)

Undulating Occurs in flagellated forms of some organisms such as that of Trypanosoma, which has a
membrane finlike ridge along the dorsal area of the organism. A flagellum may be buried in this ridge,
with the end extending as a flagellum for locomotion; movement of this structure causes
the body of the organism to undulate in wave-like movements.
Vacuole Any of various types of spaces and cavities within the cytoplasm of a protozoan cell; may
be used for storage
Vector Organism that carries and perhaps transports parasites from one host to another; snails,
other mollusks, and insects often serve as vectors for parasites as well as viruses and
bacteria
Volutin Chromosomal (chromatoid) substance found in the cytoplasm of certain protozoans,
appearing as granules

is designed to provide characteristics to assist in iden- TREATING INFECTION
tifying parasites. An extensive glossary of other terms BY PARASITES
important in the study of parasitology will be found at
the end of this book. After diagnosis of the type of organism present, a drug
must be chosen that will be effective in the treatment of a
Likelihood of Recovering specific parasitic infection. Treatment by drug therapy is
Parasites and Their Ova directed toward destroying the parasite. For amoebae, the
most common drug is Flagyl (metronidazole), which is also
Remember this answer to the question, “Will an O&P used for organisms other than parasites, such as a few se-
(stool examination for ova and parasites) detect all para- lect bacteria. Side effects often include nausea, headache,
sites?” The answer is an emphatic “No!” Technique, vomiting, insomnia, and vertigo. For giardiasis (infection by
specimen collection, and stage during which the speci- G. lamblia), the drug commonly used is Atabrine (quina-
men is collected are vital for properly finding and iden- crine HCI). Side effects often experienced when this drug
tifying parasitic infections. Only the parasites that live is prescribed and used are dizziness, headache, vomiting,
in the gastrointestinal tract and whose eggs are passed and diarrhea. Other drugs used for parasitic infections
through the feces will be diagnosed by a simple stool include Humatin (paromomycin), Furoxone (furazoli-
specimen. And if the organisms are embedded in the tis- done), and Yodoxin (iodoquinol). Some treatments utilize
sue, they may not be seen in the stool, but would need a nondrug therapy, which may include an herb known as
a swab from a mucosal membrane to find and identify Artemesia annus (par qing), as well as other natural dietary
them by morphology of the eggs or the organism itself. substances. However, the side effects of using Artemesia as
Some parasites are only detectable at certain cycles of well as other methods may result in side effects such as gas
the disease, and occur in a form that enables identifi- and bloating. Another commonly used product from plants
cation during certain cycles, such as the fever cycle for that grow in specific geographic locations is a seed extract
determining the species of protozoan responsible for from the citrus fruit (grapefruit), which appears to be an
malaria (remember there are four major species that especially effective antiparasite agent.
infect humans). Then there are also other tests specific It often takes a period of three or more months to
for parasites such as pinworms or blood parasites that eradicate an infestation of parasites. This lapse of time
cause malaria as well as a number of other bloodborne between treatment and cure is due to the various life
organisms. In addition, immunological tests for either cycles of some parasites, where they may survive while
antibodies or antigens may be required for identification undergoing certain stages of development because they
and proper treatment. may be shielded from therapeutic treatment by hiding