CASE 2

A family of four owns and operates a sheep ranch near Ennis, Montana. They also keep a few goats, which serve primarily to help mow the lawn around their house because the family doesn't drink goat's milk. However, their 16-year-old son learns something about how cheeses are made in his high school biology course, finds this interesting, and looks for additional information on the internet. He finds detailed instructions for making a soft cheese (like cottage cheese) from goat's milk, so the family decides to try this, using their own readily available source of raw goat's milk. (NOTE: Throughout human history, in many places it has been traditional to milk goats from the rear, not from the side as with cows, so that there are potentially some additional issues for this case.) The cheese is ready to eat after about two weeks, and everyone in the family tries it. They decide that the cheese is basically "OK" (and they eventually eat all of it) but not worth the trouble to make it on a regular basis.

About two months after the cheese-making incident, everyone in the family begins to experience malaise, chills, sweats, fatigue, weakness, myalgias, slight weight loss, arthralgias, and a non-productive cough. They also develop fever, which seems to come and go almost on a daily cycle, rising in the afternoon and falling during the night. These symptoms persist for three weeks without diminishing, so the family decides to visit their physician. By then, the father (who is 42 years old) and the daughter (who is 14) are experiencing lower back pain in addition to the other symptoms. Their vital signs are normal except for fever. On physical examination, all of the family members are found to have extensive tender lymphadenopathy. The mother (who is 40 years old) and the son also have splenomegaly, while the father and son have testicular tenderness that might be indicative of epididymo-orchitis. There are no other remarkable findings. The physician knows that the family has a sheep ranch, but she doesn't know about the goats. The family doesn't mention them when the physician takes a detailed history because they don't connect the cheese-making incident with their disease.

Question 2.1: What is your preliminary diagnosis?

Question 2.2: What tests should you perform?

Question 2.3: What is your final diagnosis and how is it confirmed?

Question 2.4: How does this causative agent produce disease?

Question 2.5: What is the epidemiology of this disease?

Question 2.6: How is this disease treated?

Question 2.7: How is this disease prevented?

CASE 3

A 31-year-old man visits relatives in Barcelona at the beginning of an extended vacation. He asks for ideas on how to spend his time, and his relatives suggest a leisurely tour of the northern Mediterranean coast. This sounds great, so the man spends the next six weeks enjoying the beaches and other coastal features between Gibraltar and Monaco.

About 10 months after returning to the U.S. from his vacation, the man starts to experience malaise and fatigue that slowly becomes more noticeable over a period of two months. He then starts to experience occasional diarrhea and low-grade fever. The fever, malaise, and fatigue persist over the next few weeks, and the man begins to lose weight. He then begins to experience abdominal discomfort, which worsens over the next month or so, and he continues to lose weight. At this point, he seeks medical advice.

Vital signs are T = 38.3ºC, P = 85, R = 17, BP = 135/85 mm Hg. On physical examination, the man appears somewhat malnourished. He has pronounced splenomegaly and the liver span is increased, but neither organ is tender. There is also evidence of lymphadenopathy. There are no abdominal masses and no abdominal tenderness. Bowel sounds are present. A stool sample for occult blood is negative. There are no other remarkable findings.

Question 3.1: What is your preliminary diagnosis?

Question 3.2: What tests should you perform?

Question 3.3: How can you confirm a diagnosis?

Question 3.4: What is the causative agent?

Question 3.5: How does this agent cause disease?

Question 3.6: How is this disease transmitted?

Question 3.7: How is this disease prevented?

Question 3.8: How is this disease treated?