Quantification of Schistosoma mansoni in Mouse Lungs by Radioassay and Autoradiography of 75 Se-Labeled Schistosomula

Lung radioassay and compressed lung autoradiography of 75Se-labeled schistosomula were used to quantify lung schistosomula. Recovery of schistosomula from minced lung tissue after a 4-hr incubation yielded 69.4 +/- 6.3% of the total number present as demonstrated by subsequent autoradiography of these tissues. Radioassay of lung tissue was considered a valid alternative to autoradiography only for parallel comparisons and those not requiring estimation of the actual number of schistosomula. The number of schistosomula in the lungs on day 6 was significantly correlated with radioactivity in the tail on day 1 (r2 = 91.8%). It was concluded that compressed lung autoradiography provides both an alternative to and an adjunct to standard schistosomulum recovery techniques in the assay of early S. mansoni infections.