[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 9 The Filariae
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D. State the common name for associated
conditions or diseases, if applicable.
9-12. Analyze case studies that include pertinent
patient information and laboratory data
and do the following:
A. Identify each responsible filarial
organism by scientific name, common
name, and morphologic form.
B. Identify the associated diseases and
conditions associated with the
responsible parasite.
C. Construct a life cycle associated with
each filarial parasite present that
includes corresponding epidemiology,
route of transmission, infective stage,
and diagnostic stage.
D. Propose each of the following related to
stopping and preventing nematode
infections:
1. Treatment options
2. Prevention and control plan
E. Recognize sources of error, including
but not limited to those involved in
specimen collection, processing, and
testing and propose solutions to remedy
them.
F. Interpret laboratory data, determine
specific follow-up tests to be done, and
predict the results of those identified
tests.
9-13. Identify, compare, and contrast the
similarities and differences among the
parasites discussed in this and other
chapters in this text.
9-14. Describe standard and alternative
laboratory diagnostic approaches as
appropriate for the recovery of filarial
parasites in clinical specimens.
9-15. Given prepared laboratory specimens and
with the assistance of this manual, the
learner will be able to do the following:
A. Differentiate filarial organisms from
artifacts.
B. Correctly name each filaria parasite
based on its key characteristic
structure(s).
CASE STUDY 9-1
UNDER THE MICROSCOPE
Lois is a distraught 44-year-old female visiting her primary
care physician at 9:00 a.m. She describes looking in the
mirror that morning and seeing a worm crawl across her
eye and then disappear. On her updated patient history,
she notes she had visited the African rainforest the previous
year. The physician orders a stool for ova and parasite
examination, as well as a complete blood count and differential.
The blood is drawn at 11:30 a.m. on the same
day as the office visit at a draw site near Lois’ home. The
stool parasite examination proves to be negative. The
automated blood count shows increased eosinophils and
a Giemsa stained blood film is prepared. An evening shift
medical laboratory scientist obeserves a worm-like form on
the blood smear that is 275 µm in length. There is a stained
sheath and nuclei extend to the tip of the tail.
Questions to Consider
1. What is the scientific name of the organism observed?
(Objective 9-12A)
2. What is the significance of her travel history? (Objective
9-2)
3. Determine if the blood sample was drawn appropriately.
(Objective 9-10)
4. Propose treatment options for this individual. (Objective
9-12D)
FOCUSING IN
This chapter describes a group of nematodes,
known as the filariae or filarial nematodes, in
which the adult worms live in tissue or the lymphatic
system and are thus rarely seen. The adult
filariae produce larvae called microfilariae that
are usually detected in the blood. These microfilariae
may exhibit periodicity (a concept detailed
later in the laboratory diagnosis section). Vectors
of filarial nematodes include biting insects such
as mosquitoes. Distribution of these organisms
includes Asia, Africa, South and Central Americas
and the Carribean.
MORPHOLOGY AND LIFE
CYCLE NOTES
There are two known morphologic forms of the
filariae, adult worms and larvae known as