08-04-2006, 12:00 PM
A group of six college students decides to climb Mt. Rainier on their spring break. They pack food and camping provisions except for water, which they obtain from the many freshwater mountain streams that arise at the summit. The adventure lasts a little more than a week, and all return safely and in good spirits to their classes the following week. Within the first week after their return, five of the six students report to the infirmary with profuse diarrhea and tenesmus. Each affected student experiences weakness and weight loss, and stool samples submitted to the laboratory are yellow, greasy, and foul smelling. Quadrinucleate cysts are found in four of the five samples submitted. Which of the following attributes imparts pathogenicity to the parasite involved?
A. Encystment
B. Flagellae
C. Lytic enzymes
D. Toxic metabolites
E. Ventral sucking disc
A. Encystment
B. Flagellae
C. Lytic enzymes
D. Toxic metabolites
E. Ventral sucking disc