The answer is c.
All the diseases listed in the question have significant epidemiologic and clinical features. Toxoplasmosis, for example, is generally a mild, self-limiting disease; however, severe fetal disease is possible if pregnant women ingest Toxoplasma oocysts. Consumption of uncooked meat may result in either an acute toxoplasmosis or a chronic toxoplasmosis that is associated with serious eye disease. Most adults have antibody titers to Toxoplasma and thus would have a positive Sabin-Feldman dye test.
Trichinosis most often is caused by ingestion of contaminated pork products. However, eating undercooked bear, walrus, raccoon, or possum meat also may cause this disease. Symptoms of trichinosis include muscle soreness and swollen eyes.
Although giardiasis has been classically associated with travel in Rus- sia, especially St. Petersburg (Leningrad), many cases of giardiasis caused by contaminated water have been reported in the United States as well. Diagnosis is made by detecting cysts in the stool. In some cases, diagnosis may be very difficult because of the relatively small number of cysts present. Alternatively, an enzyme immunoassay may be used to detect Giardia antigen in fecal samples.
Schistosomiasis is a worldwide public health problem. Control of this disease entails the elimination of the intermediate host snail and removal of streamside vegetation. Abdominal pain is a symptom of schistosomiasis.
Visceral larva migrans is an occupational disease of people who are in close contact with dogs and cats. The disease is caused by the nematodes Toxocara canis (dogs) and T. cati (cats) and has been recognized in young children who have close contact with pets or who eat dirt. Symptoms include skin rash, eosinophilia, and hepatosplenomegaly.