Novel equi merozoite antigen (ema-1) gene heterogeneity in a geographically isolated Theileria equi population in Croatia

Coultous, R. , Gotić, J., McCann, M., Sutton, D., Beck, R. and Shiels, B. (2022) Novel equi merozoite antigen (ema-1) gene heterogeneity in a geographically isolated Theileria equi population in Croatia. Parasites and Vectors, 15(1), 401. (doi: 10.1186/s13071-022-05484-4) (PMID:36316753) (PMCID:PMC9623909)

Abstract

Background: The apicomplexan haemoparasite Theileria equi, a causative agent of equine piroplasmosis, is an established pathogen of significant welfare and economic concern within the Croatian equine population. A previous large surveillance study of T. equi has identified two distinct parasite populations, one in the north and one in the south, geographically separated by the Dinaric Alps, which traverse the country. This study aimed to further investigate the genetic diversity within these two populations, focussing on allelic variability of the equi merozoite antigen gene, ema-1. Methods: Following nested PCR of DNA isolates, the generated ema-1 amplicons were subsequently sequenced and compared by phylogenetic analysis to available sequences representing previously described ema-1 genotypes (groups A–C). Results: Isolates from the southern T. equi population clustered with the existing ema-1 groups A and B. Strikingly, isolates from the northern population clustered into two novel ema-1 genotypes, named groups D and E. Conclusions: This detection of hitherto unreported genotypes suggests that historic geographical isolation has led to a degree of divergent evolution in this northern T. equi population. Additionally, current global regulatory testing of equine piroplasmosis relies heavily on EMA-1 based immunodiagnostics, and the discovery of unique ema-1 genotypes may question the efficacy of current diagnostics in international equine movement, with ramifications for the global equine community.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Shiels, Professor Brian and Coultous, Dr Robert
• Authors: Coultous, R., Gotić, J., McCann, M., Sutton, D., Beck, R., and Shiels, B.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Parasites and Vectors
• Publisher: BioMed Central
• ISSN: 1756-3305
• ISSN (Online): 1756-3305
• Copyright Holders: Copyright © The Author(s) 2022
• First Published: First published in Parasites and Vectors 15(1):401
• Publisher Policy: Reproduced under a Creative Commons license

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
304516		Coultous HBLB Postdoc	Brian Shiels	Horserace Betting Levy Board (HBLB)	VET/EPDF/2019-1	Institute of Biodiversity, Animal Health and Comparative Medicine