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Genetic and biological characterisation of three cryptic Eimeria operational taxonomic units that infect chickens (Gallus gallus domesticus)

Blake, Damer; Blake, Damer; Xia, Dong; Vrba, Vladimir; Tomley, Fiona; Xia, Dong; Danladi Jatau, Isa; Spiro, Simon; Nolan, Matthew J.; Underwood, Greg; Tomley, Fiona


Damer Blake

Damer Blake

Dong Xia

Vladimir Vrba

Fiona Tomley

Dong Xia

Isa Danladi Jatau

Simon Spiro

Matthew J. Nolan

Greg Underwood

Fiona Tomley


More than 68 billion chickens were produced globally in 2018, emphasising their major contribution to the production of protein for human consumption, and the importance of their pathogens. Protozoan Eimeria species are the most economically significant parasites of chickens, incurring global costs of more than UK£10.4 billion per annum. Seven Eimeria species have long been recognised to infect chickens, with three additional cryptic operational taxonomic units (OTUs) first described more than ten years ago. As the world’s farmers attempt to reduce reliance on routine use of antimicrobials in livestock production, replacing drugs that target a wide range of microbes with precise species- and sometimes strain-specific vaccines, the breakthrough of cryptic genetic types can pose serious problems. Consideration of biological characteristics including oocyst morphology, pathology caused during infection and pre-patent periods, combined with gene-coding sequences predicted from draft genome sequence assemblies, suggest that all three of these cryptic Eimeria OTUs possess sufficient genetic and biological diversity to be considered as new and distinct species. The ability of these OTUs to compromise chicken bodyweight gain and escape immunity induced by current commercially available anticoccidial vaccines indicates that they could pose a notable threat to chicken health, welfare, and productivity. We suggest the names Eimeria lata n. sp., E. nagambie n. sp. and E. zaria n. sp. for OTUs x, y and z, respectively, reflecting their appearance (x) or the origins of the first isolates of these novel species (y, z).


Blake, D., Blake, D., Vrba, V., Xia, D., Xia, D., Tomley, F., …Tomley, F. (2021). Genetic and biological characterisation of three cryptic Eimeria operational taxonomic units that infect chickens (Gallus gallus domesticus). International Journal for Parasitology,

Journal Article Type Article
Acceptance Date Dec 22, 2020
Publication Date Mar 11, 2021
Deposit Date Jan 4, 2021
Publicly Available Date Mar 24, 2021
Print ISSN 0020-7519
Publisher Elsevier
Peer Reviewed Peer Reviewed
Public URL


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