Inflammatory response caused by larvae and adults of Gnathostoma (Nematoda: Gnathostomatidae) in vertebrates of Mexico, including humans

Abstract

The aim of this study was to describe and compare the inflammatory reaction caused by Gnathostomaspp., in various tissues of wild vertebrates and humans in Mexico. Parasitized tissues were collected from 10 speciesof vertebrates from 8 states. Samples were fixed in 10% formalin, pH 7.2 and processed with standard histologicaltechniques. The lesions were classified into 4 categories. The advanced third stage larvae in fish, amphibians, and reptileswere associated with inflammatory reaction categories I and II (no injury, discrete or minimum); birds presented lesionsclassified in categories II, III, and IV (injuries minimal to discrete, moderate to severe; granulomatous); 1 humansample had lesions classified in categories III and IV (injuries moderate to severe; granulomatous). Adult parasitesin mammals generated responses in categories III and IV. Inflammatory reactions observed in the different studiedvertebrates suggest a complex host response to the presence of the parasite, causing variable tissue changes. The tissuereactions provide basic knowledge on the general principles of the pathogenesis and pathology of gnathostomiasis.