Authors
S Larcombe3; L Lempereur4; Z Durrani5; T Karagenc1; H Bilgic1; S Bakirci1; S Hacilarlioglud1; J Kinnaird3; J Thompson2; W Weir3; B Shiels3; 1 Adnan Menderes University, UK; 2 University of Edinburgh, UK; 3 University of Glasgow , UK; 4 University of Liege, Belgium; 5 University of Liverpool, UKDiscussion
Strategies for control of vector-borne apicomplexan parasites often target parasite stages in the mammalian host that cause disease, but this can result in reservoir infections that promote pathogen transmission and generate economic loss. Optimal control strategies should protect against clinical disease, block transmission and be applicable across related genera of parasites. We have used bioinformatics and transcriptomics to screen for transmission-blocking candidate antigens in Theileria annulata. A number of candidate antigen encoding genes were identified including domains that are conserved across vector-borne Apicomplexa (Babesia, Plasmodium and Theileria), including the Pfs48/45 6-cys domain and a novel cysteine-rich domain. Expression profiling confirmed candidate genes are expressed by life cycle stages within infected ticks. Candidate genes were identified that encode proteins with similarity to known transmission blocking candidates in related parasites, while one is a novel candidate conserved across vector-borne apicomplexans and has a potential role in the sexual phase of the life cycle. The results indicate that a 'One Health' approach could be utilised to develop a transmission-blocking strategy effective against vector-borne apicomplexan parasites of animals and humans. 
