Genetic and biological characterisation of three cryptic Eimeria operational taxonomic units that infect chickens (Gallus gallus domesticus). Issue 8 (July 2021)

• Record Type: Journal Article
• Authors: Blake, Damer P.; Vrba, Vladimir; Xia, Dong; Jatau, Isa Danladi; Spiro, Simon; Nolan, Matthew J.; Underwood, Greg; Tomley, Fiona M.
• Is Part Of: International journal for parasitology. Volume 51:Issue 8(2021)
• Page Start: 621
• Page End: 634
• Publication Date: 2021-07
• Subjects: Chickens -- Eimeria -- Cryptic species -- Operational taxonomic unit -- Genome sequencing -- Food security; Parasitology -- Periodicals; Parasitology -- Periodicals; Parasitologie -- Périodiques; Parasitology; Periodicals; Electronic journals; 571.999
• DOI: 10.1016/j.ijpara.2020.12.004
• Languages: English
• ISSNs: 0020-7519

Abstract

Graphical abstract: Highlights: Biology and genetics suggest cryptic Eimeria Operational Taxonomic Units (OTUs) from chickens are new species. New Eimeria spp. that infect chickens are pathogenic and require control. Anticoccidial vaccination of chickens does not control three new Eimeria spp. Abstract: 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 spp. are the most economically significant parasites of chickens, incurring global costs of more than UK £10.4 billion per annum. Seven Eimeria spp. have long been recognised to infect chickens, with three additional cryptic operational taxonomic units (OTUs) first described more than 10 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., Eimeria nagambie n. sp. and Eimeria 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).