Pulmonary Lesions in Mice Experimentally Infected with Schistosoma Mansoni

Abstract

Summary This paper presents a study of the pulmonary lesions in the lungs of mice which were infected for a second time with Schistosoma mansoni. The microscopic examinations of the lungs of these superinfected mice were made from 48 hours until 40 days after reinfection. The pulmonary lesions found in the reinfected animals were caused by the disintegration of schistosomulae, followed by obstructive endarteritis and arteriolitis. In the animals sacrificed in the more advanced stages of infection fibrous proliferation of the intimal layer of the small arteries and arterioles with a considerable reduction of the lumen was also observed. Parasites in an advanced stage of autolytic disintegration were seen surrounded by an intensive inflammatory reaction in the arterioles and capillaries. By comparing these lesions with the lesions observed in the control group, we came to the following conclusions: 1. There is retention of the schistosomulae in the pulmonary arterial vessels of the premunized mice. 2. There is high mortality of these retained parasites in different stages of their development, probably due to some unfavorable condition in the pulmonary circulation. 3. The presence of the dying and dead worms causes the development of endarteritis and arteriolitis.