• Parasites, Hosts and Diseases
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• v.37 no.4
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• pp.277-283
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• 1999

To investigate the development of a subunit vaccine against theileriosis in cattle, the DNA fragments encoding piroplasm surface protein (p33) of Theileria sergenti of a Korean isolate were expressed in baculoviruses. The expressed p33 was characterized by indirect fluorescent antibody (IFA) and western blotting analysis. The expression of p33 was mainly detected on the surface of infected Sf21 cells by IFA. The immunoblotting analysis revealed the presence of a same molecular weight protein band of p33. The antigenicity of expressed polypeptide was further examined through the inoculation of a guinea pig. The sera of guinea pigs immunized with p33 expressed cell Iysate showed similar fluorescent antibody patterns and reacted with the same molecular weight protein of T. sergenti in immunoblotting analysis, thus indicating that this protein can be a promising candidate for a subunit vaccine in the future.

• Parasites, Hosts and Diseases
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• v.35 no.2
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• pp.105-110
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• 1997

The gene encoding the 33 kDa piroplasm surface protein of Theileria sergenti isolated in Korea was cloned and the nucleotide sequence was determined by dideoxy chaill termination method. The cloned gene corresponds to 869 bps encoding an open reading frame of 283 amino acids. Comparison of the sequence between Korean and .Tapanese isolates showed 99.4% homology rate in the nucleotide sequence and 98.9% homology rate in the amino acid sequence.

• Korean Journal of Veterinary Research
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• v.61 no.4
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• pp.33.1-33.5
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• 2021

This study reports the detection and genotyping of the first clinical case of bovine anemia due to Theileria orientalis group (BATOG) in non-grazed dairy cow in upper South Korea. Blood and serum tests revealed anemia and hyperbilirubinemia from animal showing clinical symptoms, and later confirmed as piroplasmosis-positive. Follow-up surveillance on the herd revealed 2 asymptomatic cows with anemia. The three animals were confirmed theileriosis-positive and genotyping revealed the clinical and one of the asymptomatic cases have Chitose, while the other has Ikeda genotype. Clinical BATOG cases were rarely reported worldwide, and asymptomatic animals left untreated could serve as parasite reservoir.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.465-471
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• 1990

The fine structure of the inoculated Theileria sergenti on the splenectomized Korean native cattle was observed to delineate the morphological. characteristics with transmission and scanning electron microscope. The cattle was inoculated with 1.5ml cryopreserved stabilate ($5.63{\times}10^6/{\mu}l$, PE 3%). At peak parasitemia (40%), infected blood was collected, washed and then T sergenti was observed. Scanning electron micrograph of the erythrocytes infected with T sergenti appeared various irregular from involving specific swelling, and abnormal projections like acantocyte, echinocyte and knizocyte. Transmission electron microscopic studies of T sergenti showed that piroplasm possess intracytoplasmic food vacuole, rhoptries and tubule. Merozoite, $0.6{\sim}1.81{\mu}m$ to $0.4{\sim}1.21{\mu}m$ in length, surrounded by 10~15nm thickness of pellicula. which is surrounded by a single unit membrane. Various size of veil which was observed in stroma of erythrocytes infected with T sergenti, located at the proximate part of the merozoite. The merozoite multiplied by means of binary fission so that two and more oval-like merozoites in the stroma of infected erythrocyte could be observed.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.846-849
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• 2018

A group of benign Theileria species, which are often referred to as T. orientalis/T. buffeli/T. sergenti group, has low pathogenicity in cattle. Herein, we report on Theileria spp. in cattle on a farm from China. Based on phylogenetic analysis of the major piroplasm surface protein gene sequences, we detected 6 genotypes that were categorized as Types 1, 2, 3, 4, and 5 as well as an additional Type 9 genotype. The new epidemiological features of the T. orientalis/T. buffeli/T. sergenti parasites in China indicate a greater diversity in the genetics of these species than had been previously thought.

• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.64-74
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• 2024

This pilot study aimed to investigate the effects of regional and seasonal variations on the prevalence of Theileria orientalis and the hematological profile of non-grazed dairy cows in Korea. A total of 365 clinically healthy lactating Holstein Friesian cows from 26 dairy farms in 7 provinces that were categorized into northern, central, and southern regions were sampled during the warm period from July to August and the cold period from October to December. The detection of T. orientalis major piroplasm surface protein gene and the hematology non-grazed dairy cows were analyzed using peripheral blood samples. The T. orientalis prevalence was 20.0% (73/365). The prevalence in the southern region was 35.9%, which was significantly higher than that in the central (21.6%) and northern (12.9%) regions (P<0.05). The prevalence during warm period was higher (43.0%) than that during the cold season (13.5%). The infected cows showed significantly lower erythrocyte counts in the southern region (5.8±0.6 M/㎕) and during the warm period (5.8±0.7 M/㎕) compared with those in the central and northern regions and during the cold season, which affected the extended RBC parameters, including hematocrit and hemoglobin concentrations. Our findings revealed the prevalence of T. orientalis in Korea, highlighting its high occurrence during warm periods and in certain geographical regions. Climatic factors could contribute to the health and productivity of cattle, as evidenced by the prevalence of T. orientalis and its negative impact on animals.