Mitochondrial Gene Diversity and Host Specificity of Isospora in Passerine Birds

Abstract

Isosporainfections are common in both wild and captive passerine species. Many bird species have been shown to have co-evolved with a particular species ofIsospora. Disease can range from subclinical to severe and fatal, making infection and transmission of this parasite a concern for birds under managed care, particularly in institutions housing endangered species for breeding and reintroduction purposes. Whether birds in mixed-species enclosures represent a risk factor for severe isosporiasis due to infection with non-host-adapted strains is of concern for institutions managing these populations. To begin answering this question, we sought to characterize the host-specificity ofIsosporaspp. in a large number of passerine birdsviaretrospective sequencing of mitochondrial gene cytochromecoxidase subunit I (COI). Despite outliers,Isosporasequences largely grouped by host species and/or host family. Additional research is warranted into the degree of interspecies transmission and host-switching ofIsosporaparasites, and risk factors for the development of severe disease in passerine birds.