Integrative taxonomy for the traditional coccidians (Chromista: Miozoa: Eimeriidae) from island canaries (Aves: Passeriformes: Fringillidae): Worldwide distribution, morphological and molecular characterization, revaluations and establishment of junior synonyms

Abstract

Island canaries Serinus canaria (Linnaeus) are finches native to the North Atlantic Islands, however, they have a worldwide distribution in captivity due to their relevance as a pet bird. Coccidians are the most reported parasites of passerines worldwide, both in the wild and in captivity, being frequently associated with disease in passerines kept in rehabilitation centers and commercial breeders. This study aimed to identify coccidians from island canaries kept in captivity in Brazil. Three hundred and fifteen genomic DNA extracted from fecal samples of island canaries from different breeders from Southern and Southeastern Brazil were used to perform a nested PCR assay to amplify a partial fragment of the 28S small subunit ribosomal RNA gene (28S) of Isospora spp. Microscopic screening and morphological identification of Isospora oocysts was performed in fecal samples corresponding to PCR positive DNA samples. Fecal samples have been formalin-stored for approximately four years. Positivity rate for both microscopy and PCR was 10.5% (33/315). Posteriorly, Isospora serini (Aragão, 1933) Box, 1975 and Isospora canaria Box, 1975 were morphologically identified from fresh fecal samples of island canaries maintained by a breeder in the State of São Paulo, Southeastern Brazil, providing a genotypic characterization via sequencing of the mitochondrial cytochrome c oxidase subunit 1 (COI) and 28S genes. The 28S and COI sequences referring to the morphological identification of I. canaria was, respectively, 100% and 99% similar to sequences deposited as Isospora serinuse Yang, Brice, Elliot & Ryan, 2015 from island canaries kept in a rehabilitation center in Australia. The COI sequence referring to the morphological identification of I. serini was 100% similar to a sequence of an extraintestinal Isospora, corroborating this identification/sequencing since I. serini is the first isosporan with an extra-intestinal cycle demonstrated. The comparison of morphological and molecular data from I. canaria and I. serini from this study with published data of Isospora spp. from canaries worldwide, allowed the specific identification from preliminary generic identifications, correction of misidentifications, as well as the establishment of junior synonyms. Finally, this study provides morphological and molecular data that ensure the correct identification of the two Isospora spp. from island canaries in future studies worldwide.