Eimeria varia Upton, Campbell, Weigel & McKown, 1990 is a Junior Synonym of Eimeria megabubonis Upton, Campbell, Weigel & McKown, 1990



The present work aims to morphologically and molecularly characterize an Eimeria sp. recovered from an adult, captive barred owl Strix varia in Mississippi, USA. While the owl was shedding oocysts, no clinical signs of coccidiosis were observed.

Materials and Methods

Oocysts collected from a barred owl, S. varia were isolated from feces by fecal flotation and characterized by light microscopy. The oocysts were allowed to sporulate in K2Cr2O7 for 7 days and measured for comparison with previously described Eimeria species. Genomic DNA was extracted from measured oocysts and the cytochrome c oxidase subunit 1 mitochondrial gene was amplified and sequenced for comparison and phylogenetic analyses with publicly available sequence data.


Oocysts collected from S. varia were morphologically and molecularly consistent with all previous accounts of Eimeria megabubonis from the great horned owl Bubo virginianus and morphologically consistent with the only account of Eimeria varia from S. varia. Phylogenetic analyses grouped the E. megabubonis sequence from the present study with previously reported sequences from E. megabubonis.


Morphological and molecular data from oocysts collected in this study reveal S. varia is a host for E. megabubonis. Agreement between current data, morphological and molecular data of E. megabubonis, and morphological data from the original description of E. varia indicates E. varia is a junior synonym of E. megabubonis.

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This work was funded in part by the Department of Comparative Biomedical Sciences and Department of Pathobiology and Population Medicine at Mississippi State University’s College of Veterinary Medicine.

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Correspondence to Ethan T. Woodyard.

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The authors declare no conflicts of interest.

Ethical Approval

The owl from which fecal samples were collected for the present study is housed in compliance with a protocol approved by the Institutional Animal Care and Use Committee at Mississippi State University for the captive maintenance of wildlife for research and teaching purposes in accordance with federal, local, and institutional rules and regulations.

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Woodyard, E.T., Rosser, T.G., Rush, S.A. et al. Eimeria varia Upton, Campbell, Weigel & McKown, 1990 is a Junior Synonym of Eimeria megabubonis Upton, Campbell, Weigel & McKown, 1990. Acta Parasit. (2021). https://doi.org/10.1007/s11686-020-00317-9

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  • Barred owl
  • Coccidia
  • Eimeria megabubonis
  • Eimeria varia
  • Strix varia