Page 276 - parasitology for medical and clinical laboratoryprofessionals

256 CHAPTER 12

■ Identifying infected persons and requiring duodenal fluid is collected in the same manner. Sputum
treatment is collected following a deep cough or as bronchial
■ Effective vaccines as well as more effective washings performed by a physician. Specimens to be
parasiticides examined for parasites of the blood, such as intracel-
lular malaria, require a simple phlebotomy procedure.
Occasionally P. westermani or Schistosom hematobium
CLASSIFICATION OF PARASITES ova may be found in the urine, or when fecal contami-
nation is the source of the parasite or its ova, as well as
FOR IDENTIFICATION a chance ectoparasite such as scabies that falls into the
There are two broad groups of parasites that are eas- urine. Nits may also be plucked from the hair with for-
ily determined. The first and most elementary step is ceps for microscopic examination and identification.
to place the organism into one of the following broad It is rare when any of the other body fluids would harbor
groups. Ectoparasites live on the exterior of the body, a parasite, and if so would be a special procedure using
on the skin and in the hair, and are said to cause infesta- some of the same techniques as used routinely in the
tions. They may also function as vectors, or organisms parasitology department.
that transmit disease into the human body. The second Endoparasites that require a fecal specimen are the
group, called endoparasites, are defined as those that simplest to collect. The chances of recovering a parasite
dwell in cavities, tissues, and organs of the body and from a clinical specimen are drastically increased when
this group of parasites is said to initiate an infection in certain collection procedures are followed. It is some-
the body. Each of these two groups is further defined as times necessary to perform identification procedures on
follows: more than one sample, and in a timed manner, in order
to optimize the percentages of recovering and identifying
Ectoparasites Lice, mites, and other arthropods the organism. In addition, it is necessary to know about
(jointed legs) the life cycle and epidemiology of the suspected organ-
Includes crustaceans, insects, and ism and the criteria for specimen collection, handling,
arachnids (spiders, ticks, scorpions) and transport of the sample. It is also wise for the labora-

Parasite tory professional to follow safe practices such as the use
Endoparasites Protozoa (amoebae, ciliates, flagellates, of hand hygiene before and after gloving and removal of
sporozoans) the gloves, and thorough cleaning of work surfaces fol-
Includes helminths (worms) such as lowing the handling of clinical specimens. Many of these
flukes, tapeworms, and roundworms parasitic organisms are highly contagious, and are easily
1. Intestinal and atrial (body cavity) passed to the unwary person handling the sample.
parasites Specimens should be obtained with the use of
2. Blood and tissue parasites specially designed containers or in a clean but dry leak-
proof receptacle with a lid to prevent leakage. Specimens
should not be mixed with urine if collected in a bedpan,
SPECIMEN COLLECTION or with any other contaminants. In addition, they should
be collected prior to the initial doses of any antiparasitic
The collection of specimens includes feces, sputum, medications, or any dyes. Those patients taking medi-
blood, skin scrapings, tissue specimens, and even urine cations for diarrhea or laxatives, as well as barium for
and other body fluids such as cerebrospinal fluid (CSF) X-rays of the intestine should stop taking these medica-
and duodenal aspirates. Ectoparasites are often scraped tions or following a barium X-ray for one week before
from the skin with a scalpel blade or the edge of a micro- attempting to collect a viable sample.
scope slide and examined using a solution that might When specimens are collected at home, in a clinic,
provide for staining or differentiation of the organism by or in a physician’s office and must be transported, they
microscopic exam. CSF requires a needle aspiration of must be preserved to enhance recovery of any parasites
the fluid of the brain and spine meninges; aspiration of present, but it should be remembered that trophozoites