Pulmonary changes during acute experimental murine mansoni schistosomiasis

Area of Science:

• Immunology
• Pathology
• Respiratory Medicine

Background:

• Acute schistosomiasis has been associated with respiratory symptoms, including dry cough, dyspnea, and bronchial asthma manifestations.
• The precise type and pathogenesis of these pulmonary conditions in acute schistosomiasis remain incompletely understood.

Purpose of the Study:

• To investigate the type and pathogenesis of respiratory conditions observed in acute schistosomiasis.
• To establish and utilize an experimental mouse model for studying acute schistosomiasis-induced lung pathology.

Main Methods:

• An experimental mouse model was employed, with forty mice divided into three infected groups and one control group.
• Animals were examined at 7, 28-35, and 40 days post-exposure to Schistosoma cercariae.
• Histopathological analysis and indirect immunofluorescence were used to assess lung tissues and antigen presence.

Main Results:

• Multifocal interstitial pneumonitis was identified in the acute phase of infection (28-35 days), affecting peribronchial, peribronchiolar, and subpleural tissues.
• This pneumonitis was absent in other infection phases and no schistosomal antigens were detected in acute-phase lung lesions.
• The observed pneumonitis was hypothesized to result from inflammatory mediators originating from hepatic lesions and transported via the bloodstream.

Conclusions:

• Acute schistosomiasis can induce interstitial pneumonitis in a mouse model.
• The lung pathology appears to be immunologically mediated, driven by inflammatory products from liver lesions rather than direct parasite presence in the lungs.
• These findings suggest a mechanism for respiratory manifestations in acute schistosomiasis, linking liver inflammation to lung pathology.