Novel zoonotic Enterocytozoon and Encephalitozoon genotypes in domestic pigeons (Columba livia domestica) in Iran: Public health implications

To determine the occurrence of microsporidiosis in domestic pigeons in Iran, privately-owned pigeons presenting weight loss and diarrhea were tested through molecular and histopathological methods. Multiplex-PCR findings showed 57%, 30%, and 14% positivity for Enterocytozoon, Encephalitozoon, and mixed infection in the fecal samples, respectively. A novel Enterocytozoon bieneusi genotype, named IrnEb1, falling into zoonotic group 1 of E. bieneusi, and a novel genotype of Encephalitozoon hellem, named Irn2E, clustering as a sister taxon to genotype 2B were identified in pigeons for the first time using Sanger sequencing and phylogenetic analyses. Histopathological examination revealed the occurrence of non-suppurative enteritis, nephritis, pneumonia, hepatitis, and encephalitis associated with focal necrosis and inflammatory cell infiltration. Data shown herein present a high prevalence of microsporidiosis in pigeons in Iran. Considering that both detected microsporidian species are zoonotic parasites, these findings suggest that the infected pigeons could pose a risk to public health.