The genus Trichinella is currently considered a complex of nine species and four additional genotypes (T6, T8, T9, and T13) of undetermined taxonomic status. Other than the existence of two clades defined by the presence or absence of a collagen capsule (cyst) surrounding parasite larvae in infected muscles, there are no morphologic differences. Each taxon can be identified by means of PCR assay and DNA sequencing performed on larvae collected from muscles samples from infected animals or humans.
