Pythium insidiosum complex hides a cryptic novel species: Pythium periculosum.

Early phylogenetic analysis of Pythium insidiosum, the etiologic agent of pythiosis in mammals, showed the presence of a complex comprising three monophyletic clusters. Two included isolates recovered from cases of pythiosis in the Americas (Cluster I) and Asia (Cluster II), whereas the third cluster included four diverged isolates three from humans in Thailand and the USA, and one isolate from a USA spectacled bear (Cluster III). Thereafter, several phylogenetic analyses confirmed the presence of at least three monophyletic clusters, with most isolates placed in clusters I and II.

Geographic distribution of Pythium insidiosum infections in the United States.

Objective: To describe the geographic distribution of infections caused by Pythium insidiosum in dogs, horses, and other animal species in the US.

Animals: For the last 20 years, we have collected data from cases of pythiosis in 1,150 horses, 467 dogs, and other species (59) from various geographic locations in the US.

Procedures: Due to lost data (from 2006 to 2016), the selected cases include years 2000 to 2005 and 2016 to 2020.

The taxonomy of two uncultivated fungal mammalian pathogens is revealed through phylogeny and population genetic analyses.

Ever since the uncultivated South American fungal pathogen Lacazia loboi was first described 90 years ago, its etiology and evolutionary traits have been at the center of endless controversies. This pathogen infects the skin of humans and as long believed, dolphin skin. However, recent DNA analyses of infected dolphins placed its DNA sequences within Paracoccidioides species.