Page 218 - parasitology for medical and clinical laboratoryprofessionals

198 CHAPTER 8

CASE STUDIES

1. A young man from southeast Japan became alarmed when he developed a cough,
which grew more severe over a period of several weeks, and then he noted flecks
of blood in his sputum. He knew that a number of species of parasites were often
present in raw or poorly cooked crabs and other seafood. The treating physician
suspected pneumonia and obtained a chest X-ray as well as a sputum culture for
pathogenic bacteria. The sputum culture was negative for bacterial pathogens and
the chest X-ray did not reveal infiltrates suggestive of pneumonia. The physician con-
ferred with a particularly astute microbiologist, who suggested a wet mount of a
repeat sputum specimen and, upon examination, found helminth eggs. What is the
probable causative condition and species of the eggs of the organism represented in
the sputum?
2. A business entrepreneur from the United States spent a year teaching business prac-
tices at a university in Vietnam. For several months before returning to his home, he
had been experiencing vague abdominal pain punctuated with periods of diarrhea.
Upon his return home, he began to become jaundiced and suffered from indiges-
tion. Alarmed, he visited his family physician who found that he had an obstruction
of the bile duct and as well as eosinophilia. What would be the most likely parasite or
parasites from which he is suffering?
3. A group of university students from North America embarked on an archaeological
expedition to enhance their studies of ancient history. They traveled to a number of
countries in the Mideast and Far East over a 2-week period. During a break from their
travels they stopped along the Nile River in Egypt, near the Aswan Dam. Several of the
students waded into the water near the shore. After returning home, Samuel noted
small reddened areas on his feet but ignored them at the time. A short time later, he
began to experience stomach pain along with bloody diarrhea and urine, accompa-
nied by a tender abdomen. Upon a visit to his physician, he was questioned about any
travels in the recent past. What parasitic organism was the physician suspecting?

STUDY QUESTIONS

1. Tissue flukes are known to infect human organs. 7. At what period in history were entire armies
Name these organs. affected by what is believed to be schistosomiasis?
2. Name the range of size in parasitic flatworms. 8. What are the seven stages in the life cycle of the
3. What is a limiting factor in the spread of flukes over flukes?
a geographic area? 9. List the three species of Schistosoma that are
4. How do the infective cercariae move about to find a implicated most frequently in human infections.
host? 10. Break down the word schistosoma, and give the
5. How do fasciola and schistosoma organisms cause literal meaning of the word.
tissue damage? 11. List the steps in the development of a human
6. What were the first prevalent symptoms that led infection by P. westermani.
early medics to suspect schistosomiasis?