Infection dynamics of Theileria annulata over a disease season following cell line vaccination

Publication date: Available online 7 December 2018Source: Veterinary ParasitologyAuthor(s): Huseyin Bilgin Bilgic, Ayça Aksulu, Serkan Bakırcı, Ahmet Hakan Unlu, Onur Kose, Selin Hacılarlıoglu, William Weir, Tulin KaragencAbstractTropical theileriosis is a tick-borne haemoparasitic disease of cattle caused by the protozoan parasite Theileria annulata. Globally, the economic impact of the disease is immense and enhanced control measures would improve livestock production in endemic regions. Immunisation with a live attenuated vaccine is an effective and widely used control method, however, the repeated use of live vaccines may have an impact on the field parasite population at a genetic level. Additionally, there has been an increasing number of reports of vaccine breakthrough cases in recent years. Thus, the present study was designed to evaluate the genetic composition of a parasite population over a disease season in a locality where live cell line vaccination is practised. A diverse range of parasite genotypes was identified and every T. annulata positive cattle blood sample harboured multiple parasite genotypes. An alteration in the major genotype and an increasing multiplicity of infection in individual animals was observed over the course of the disease season. Vaccination status was found not to effect within-host multiplicity of infection, while a significantly higher number of genotypes was detected in grazed cattle compared to non-grazed ones. A degree of genet...
Source: Veterinary Parasitology - Category: Veterinary Research Source Type: research