No abstract

Oriental theileriosis, a tick-borne disease of bovids caused by members of the Theileria orientalis complex, has a worldwide distribution. Globally, at least 11 distinct genotypes of T. orientalis complex, including type 1 (chitose), type 2 (ikeda), type 3 (buffeli), types 4 to 8, and N1-N3, have been described based on the sequence of the major piroplasm surface protein (MPSP) gene. Of these 11 genotypes, mainly ikeda and chitose are known to be pathogenic and cause considerable morbidity (including high fever, anaemia, jaundice and abortion), production losses and/or mortality in cattle. Mixed infections with two or more genotypes of T. orientalis is common, but do not always lead to a clinical disease, posing challenges in the diagnosis of asymptomatic or subclinical forms of oriental theileriosis. The diagnosis of oriental theileriosis is usually based on clinical signs, the detection of piroplasms of T. orientalis in blood smears, and/or the use of serological or molecular techniques. This paper reviews current methods used for the diagnosis of T. orientalis infections and the genetic characterisation of members of the T. orientalis complex, and proposes that advanced genomic tools should be established for investigations of these and related haemoparasites.

No abstract

This study reports an outbreak of oriental theileriosis in dairy cattle imported to Vietnam from Australia. Following clinical and pathological diagnoses, a total of 112 cattle blood samples were divided into three groups and tested using multiplexed tandem PCR. Group 1 were from aborted heifers in Vietnam; group 2 were from cattle before shipment from group 1 cattle and group 3 were from the same batch of cattle but transported to Taiwan. Theileria orientalis DNA was detected in 72·3% cattle. The prevalences of T. orientalis in groups 1, 2 and 3 were 77·6, 86·9 and 57·5%, respectively, and the difference in prevalence was significant between groups 1 and 3 (P < 0·0001). The infection intensities of genotypes chitose and ikeda of T. orientalis were higher in groups 1 (57 721 and 33 709, respectively) and 3 (5897 and 61 766, respectively) than those in group 2 (2071 and 6331, respectively). Phylogenetic analyses of the major piroplasm surface protein sequences revealed that genotypes chitose and ikeda determined herein were closely related to those previously reported from Australia. This first report of an outbreak of oriental theileriosis in imported cattle emphasizes improved measures for the export and import of cattle infected with T. orientalis.

This study reports the first molecular characterization of Theileria orientalis in local breeds of cattle in Ethiopia. A conventional PCR utilizing major piroplasm surface protein (MPSP) gene and an established multiplexed tandem PCR (MT-PCR) were used to characterize T. orientalis and to assess the infection intensity, respectively. Of 232 blood samples tested, T. orientalis DNA was detected in only 2.2% of samples using conventional PCR; two genotypes buffeli (1.3%; 3/232) and type 5 (0.9%; 2/232) of T. orientalis were detected. Phylogenetic analysis revealed that the buffeli MPSP sequences from Ethiopia were closely related to those reported from Kenya, Sri Lanka and Myanmar, and type 5 sequences from Ethiopia grouped with those from Korea, Japan, Vietnam and Thailand. A higher number of samples (3.9%; 9/232) were test-positive by MT-PCR and four genotypes (buffeli, chitose, ikeda and type 5) of T. orientalis were detected. The average intensity of infections with genotypes buffeli (DNA copy numbers 11,056) and type 5 (7508) were significantly higher (P<0.0001) than the pathogenic genotype ikeda (61 DNA copies). This first insight into T. orientalis from cattle in Ethiopia using MPSP gene provides a basis for future studies of T. orientalis in various agroclimatic zones and of the impact of oriental theilerosis on cattle in this and other countries of Africa.