An enzymatic method (phospholipase B) for studies on cestode infection (Hymenolepis nana) and its suppression by chemotherapy.

The phospholipase B activity of the small intestine of mice infected with Hymenolepis nana has been studied to determine its value as a laboratory test for the presence of parasites and the chemotherapeutic effects of antitapeworm drugs. Mice infected with 500 H. nana eggs were examined on the 21st day of infection and the phospholipase B content of homogenates of small intestine was determined using lysolecithin (6.6 x 10(-3) M) as the substrate. Some of the infected animals were treated with niclosamide according to schedules and doses known to affect worm development. Presence or absence of parasites was verified by visual inspection of the intestinal content. The enzymatic and visual methods gave equivalent results in both infected-not treated and infected-treated groups. Special features of niclosamide action (relative refractoriness of the early parasitic forms, enhanced effect of multiple doses) have been confirmed. The enzymatic method is proposed as a procedure for laboratory testing in chemotherapeutic investigations.