Page 232 - parasitology for medical and clinical laboratoryprofessionals

212 CHAPTER 9

trichinellosis was established. Stool specimens are not other parasitic infections, the white blood cells called
used to determine infection by T. spiralis, but when eosinophils may be a valuable indicator of an invasive
necessary a muscle biopsy may be performed. As in disease.

CASE STUDIES

1. A group of factory workers from the Southeast had been planning a hunting trip to
Wisconsin for years. Finally, they were able to arrange time off and had secured a
hunting cabin deep in a rural area. It was the dream of several of them to kill a bear, eat
the meat, and take the skin and the head for curing and mounting. After a successful
hunt in which two bears were dispatched, the friends roasted and ate the meat over
a large camp fire. The hunt concluded, they salted the skins with the heads attached,
and travelled back to their homes. Several weeks later, most of the men complained
of nausea, vomiting, epigastric pain, coughs, and blurred vision. Each person with
these symptoms visited their family physician. Blood tests revealed eosinophilia, and
a physical exam showed edema about the eyes, rash, and breathing difficulties. What
would be the most likely parasite from which the men are suffering?
2. Julian, a college student in western Canada, obtained a summer job working at a local
animal shelter. Part of his duties entailed picking up stray dogs, cleaning the pens
where the dogs live, and disposing of the fecal materials by burying them. Some of
the dogs were involved with herding sheep, but have become old and physically
unable to continue their duties, or were abandoned by their owners. A year after
completing this summer job, Julian begins to suffer from severe coughs and chest
pain, and seeks medical attention from the student health center at the university he
attends. What would be a possible parasite from which Julian is suffering?

STUDY QUESTIONS

1. Name the two cestode groups that contribute most 7. How did Aristotle describe the appearance of the
often to human infection. cysticercus structure?
2. How do the eggs of the taeniid species reach the 8. What animal is affected by the Echinococcus granu-
intermediate host? losus organism and how does it manifest itself?
3. Which of the tapeworms, T. saginata or T. solium, 9. Why do Jewish and Muslim religions have certain
become the largest, and what are their approximate prohibitions on eating certain meats, particularly
lengths? pork?
4. Are both male and female organisms found in the 10. In your own thinking, how did observations of meat
cestodes? If not, what is the form of reproduction conditions lead to official offices responsible for
called for these organisms? food safety?
5. What is a valuable characteristic used in differenti- 11. Eating sheep meat by dogs led to the development
ating the eggs of pseudophyllidean tapeworms and of hydatid cysts, which was determined by whom,
cyclophyllidean species? in 1853?
6. With what animals are the cestodes called T. sagi- 12. What is the common name for Diphyllobothrium
nata and T. solium associated? latum, and how is it normally contracted?