RESUMO
Rats given one infection showed a pronounced elevation of phospholipase B in the proximal half of the small intestine by the end of the 1st week, with a gradual decline to values within the range for uninfected controls by the 4th week. The distal half showed a more prolonged elevation, with a decline to the control range by the 5th week. Eosinophils (carriers of the enzyme) in the bone marrow were increased at days 5--21. At termination of the experiment on day 35, the marrow and combined gut activities had declined to normal levels. In the second experiment, rats infected once showed similar B activity in the gut and eosinophil production in the bone marrow to those noted in rats of the first experiment. However, rats challenged 37 days after the first infection showed earlier but less sustained B and eosinophil responses. This anamnestic-like response was also noted in the lungs, where the B activity was more pronounced and sustained than was evident in the once-infected rats. This association between marrow eosinopoiesis and B elevations is similar to that reported from studies with other parasite models, suggesting a common host response to tissue helminths worthy of study to determine its relation to the welfare of the host and/or detriment to the parasites.