Mortality in Syrian hamsters infected with Paragonimus kellicotti.

In an attempt to find a small animal model for paragonimiasis, Syrian hamsters were infected with between 1 and 16 metacercariae of Paragonimus kellicotti. A definitive mortality dose-response was observed with 90% of all hamsters given 3 or more parasites succumbing to the infection within 35 days. Hamsters demonstrated acute pleuritis, reactive mesothelial hyperplasia, subpleural accumulations of reactive and mature plasma cells, neovascularization, fibrohistiocytic thickening with and without giant cells, raised fibroconnective tissue lesions, and granulomatous inflammation with hemorrhage. Perivascular plasmacytic (lymphocytic) infiltrate, multifocal bronchopneumonia, and parenchymal necrotizing suppurative granulomatous inflammation, hemorrhagic pneumonia, and diffuse sprinkling of eosinophils, neutrophils, and intraalveolar macrophages also were observed. The response observed here may represent a new small animal mortality model useful in the search for new compounds to treat early trematode infections.