UNASSIGNED: Theileria orientalis, an economically significant tick-borne hemoparasite, infects cattle globally. The T. orientalis Ikeda genotype, transmitted by Haemaphysalis longicornis ticks, is associated with clinical manifestations characterized by anemia, abortions, and mortality, although subclinical infections prevail. Despite the common occurrence of subclinical infections, therapeutic interventions targeting T. orientalis Ikeda in such cases are currently lacking, impeding effective parasite control measures. To address this critical knowledge gap, we assessed the efficacy of buparvaquone (BPQ) in eliminating the T. orientalis Ikeda, US isolate, in sub-clinically infected cattle.
UNASSIGNED: Twelve sub-clinically infected calves, identified by the presence of T. orientalis in peripheral blood alongside the absence of fever and anemia, were enrolled in the study. Six calves received two treatments of the BPQ label dose (2.5 mg/kg) at a 48-h interval, while additional three calves received the drug at a dosage of 6 mg/kg following the same regimen. Three untreated calves served as controls.
UNASSIGNED: Endpoint and quantitative PCR analyses revealed that BPQ exerted a transient effect on T. orientalis parasitemia. Parasites remained undetectable in peripheral blood until weeks 4 and 11 post-treatment in animals administered 2.5 mg/kg and 6 mg/kg of BPQ, respectively. Intriguingly, following recrudescence, administering 6 mg/kg to animals previously treated with 2.5 mg/kg did not result in a reduction in parasite load. Pharmacokinetic analysis data suggested that escalating the dosage led to a less than proportional increase in serum concentrations of BPQ. Moreover, a significant yet reversible decrease (p < 0.05) in blood urea nitrogen was observed in animals treated with the drug, irrespective of the dosage. Despite parasitemia relapse, animals treated with 6 mg/kg BPQ exhibited a noteworthy decrease (p < 0.05) in IgG levels specific to the T. orientalis major piroplasm surface protein compared to controls and animals treated with 2.5 mg/kg of the drug.
UNASSIGNED: BPQ did not demonstrate efficacy in clearing subclinical T. orientalis Ikeda infection. Future investigations are warranted to explore innovative therapeutic modalities that, in synergy with vaccines and diagnostic assays, can facilitate the development of comprehensive programs aimed at controlling and eradicating this parasite.

UNASSIGNED: This study was designed to determine the molecular prevalence of hemoparasites and their associations with Mafriwal cattle\'s age groups.
UNASSIGNED: Blood samples were taken from the coccygeal veins of calves (n = 92), yearlings (n = 95), lactating (n = 90), and dry (n = 94) cows, which were subjected to microscopic and molecular identification of hemoparasites. The prevalence rate was determined based on the proportion of infected samples in the observed samples. Associations between hemoparasitism and different age groups of Mafriwal cattle were determined by the odds ratio and Fisher\'s exact test.
UNASSIGNED: Babesia bigemina was the most prevalent hemoparasite in monospecies infection (20.8%), while the co-infection of Anaplasma marginale and B. bigemina (36.4%) had the highest molecular prevalence. Highly significant associations of hemoparasitism were observed between calves and yearlings (p < 0.001, Odds ratio = 21.340, 95% CI = 3.200-907.871), lactating (p < 0.01, Odds ratio = 6.600, 95% CI = 1.808-36.516), and dry (p < 0.001, Odds ratio = 10.457, 95% CI = 2.363-96.242) cows. Nevertheless, calves and yearlings were 2-4 times more likely to be co-infected with multiple hemoparasite species in comparison to older age groups.
UNASSIGNED: Mafriwal cattle were more susceptible to hemoparasitism with advancing age, but the younger calves were more prone to be co-infected with multiple hemoparasite species.

Ticks are an important type of pathogen transmission vector, and pathogens not only cause serious harm to livestock but can also infect humans. Because of the roles that ticks play in disease transmission, reducing tick pathogen infectivity has become increasingly important and requires the identification and characterization of these pathogens and their interaction mechanisms. In this study, we determined the miRNA expression profile of Hemaphysalis longicornis infected with Theileria orientalis, predicted the target genes of miRNAs involved in this infection process, and investigated the role of miRNA target recognition during host-pathogen interactions. The results showed that longipain is a target gene of miR-5309, which was differentially expressed at different developmental stages and in various tissues in the control group. However, the miR-5309 level was reduced in the infection group. Analysis of the interaction between miRNA and the target gene showed that miR-5309 negatively regulated the expression of the longipain protein during the infection of H. longicornis with T. orientalis. To verify this inference, we compared longipain with the blocking agent orientalis. In this study, the expression of longipain was upregulated by the inhibition of miR-5309 in ticks, and the ability of the antibody produced by the tick-derived protein to attenuate T. orientalis infection was verified through animal immunity and antigen-antibody binding tests. The results showed that expression of the longipain + GST fusion protein caused the cattle to produce antibodies that could be successfully captured by ticks, and cellular immunity was subsequently activated in the ticks, resulting in a subtractive effect on T. orientalis infection. This research provides ideas for the control of ticks and tickborne diseases and a research basis for studying the mechanism underlying the interaction between ticks and pathogens.

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/µl) and during the warm period (5.8 ± 0.7 M/µl) 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.

Oriental theileriosis, a disease primarily impacting cattle is caused by an apicomplexan hemoprotozoan parasite, Theileria orientalis. It has now become established in the Australasia region. The organism was long considered a benign cause of persistent infections; however, an increase in clinical outbreaks since 2006 in the eastern Australian states and New Zealand was associated with the identification of the pathogenic Ikeda (Type 2) and Chitose (Type 1) genotypes. Unlike the pathogenic T. parva and T. annulate, which target leucocytes, clinical manifestation with T. orientalis is due to its effects on erythrocytes, with the infection sometimes designated as Theileria associated bovine anemia (TABA). In Australia and New Zealand, the tick Haemaphysalis longicornis is the principal vector, though other Haemaphysalis species are also likely vectors. The endemic status of infection with pathogenic genotypes in areas with low or absent tick populations is an apparent paradox that may be attributable to alternative modes of transmission, such as mechanical transmission by hematophagous insects (lice, mosquitoes, and biting flies), vertical transmission, and transmission via iatrogenic means. This review addresses the evidence for the different modes of transmission of T. orientalis with particular focus on the reported and potential vectors in Australasia.

Theileria orientalis Ikeda has caused an epidemic of bovine anemia and abortion across several U.S. states. This apicomplexan hemoparasite is transmitted by Haemaphysalis longicornis ticks; however, it is unknown if other North American ticks are competent vectors. Since the disease movement is largely determined by the host tick range(s), the prediction of the T. orientalis spread among U.S. cattle populations requires determination of additional competent tick vectors. Although Rhipicephalus microplus has mostly been eradicated from the U.S., outbreaks in populations occur frequently, and the U.S. remains at risk for reintroduction. Since R. microplus is a vector of Theileria equi and T. orientalis DNA has been detected in R. microplus, the goal of this study was to determine whether R. microplus is a competent vector of T. orientalis. Larval R. microplus were applied to a splenectomized, T. orientalis Ikeda-infected calf for parasite acquisition, removed as molted adults, and applied to two T. orientalis naïve, splenectomized calves for transmission. After 60 days, the naïve calves remained negative for T. orientalis by PCR and cytology. Additionally, T. orientalis was not detected in the salivary glands or larval progeny of acquisition-fed adults. These data suggest that R. microplus is not a competent vector of the U.S. T. orientalis Ikeda isolate.

In 2017, clinical disease and mortality in cattle associated with Theileria orientalis Ikeda was reported in Virginia, U.S. The exotic tick, Haemaphysalis longicornis, is a competent vector for this species. White-tailed deer (Odocoileus virginianus) are commonly infested with H. longicornis in the eastern U.S. and are also infected with several genotypes of piroplasms such as a Theileria sp. (often called Theileria cervi-like), Babesia odocoilei, and Babesia sp. H10. However, it is currently unknown if deer are susceptible to T. orientalis and can act as potential hosts. In this study, we tested 552 white-tailed deer samples from the southeastern U.S. to determine the presence of T. orientalis. We used a PCR-RFLP to test 293 (53%) of these samples to distinguish between piroplasm genera. A total of 189 white-tailed deer were positive with Theileria, 47 were positive with Babesia, and 57 did not amplify. Because this assay does not determine species, we sequenced 30 random samples targeting a fragment of the 18S rRNA gene. Although a high diversity of Theileria and Babesia spp. were detected, none were T. orientalis. All 552 samples were then screened with a T. orientalis specific real-time PCR protocol, but none were positive for T. orientalis. Our data suggests that white-tailed deer are commonly infected with piroplasm species but not T. orientalis.

Theileria orientalis (T. orientalis) is a benign species of Theileria that is found all throughout the world, including Egypt. The purpose of this work was to determine the current status of T. orientalis infection in cattle, as well as to define T. orientalis genetic diversity using the major piroplasm surface protein (MPSP) genes. In 2020, blood samples from 500 asymptomatic cattle were collected, which live in four different governorates at northern Egypt and examined using PCR assay based on MPSP gene. Overall, 44 blood samples (8.8%, 44/500) were positive for T. orientalis, and the highest prevalence rate was observed in Kafer ElSheikh while it was relatively low in Gharbia governorate. Moreover, based on multivariable analysis, the risk of infection with T. orientalis infection was higher in mixed breed cattle and in animals of age group more than 3 years compared to other. Additionally, absence of acaricide application, infestation with ticks, and communal grazing system were identified as potential risk factors for T. orientalis infection. Phylogenetic analysis revealed that the isolates studied belonged to two MPSP genotypes, types 1 and 2. These findings reveal that the MPSP genotypes discovered in the present work displayed genetic variation that was linked to geographic area. Therefore, further research should be focused on developing an effective T. orientalis monitoring and preventive program.

This article sets out to document and summarise the New Zealand epidemic and the epidemiological research conducted on the epizootic of bovine anaemia associated with Theileria orientalis Ikeda type infection, which began in New Zealand in August 2012. As New Zealand has no other pathogenic tick-borne cattle haemoparasites, the effects of the T. orientalis Ikeda type infection observed in affected herds and individual animals were not confounded by other concurrent haemoparasite infections, as was possibly the case in other countries. This has resulted in an unbiased perspective of a new disease. In addition, as both New Zealand\'s beef and dairy cattle systems are seasonally based, this has led to a different epidemiological presentation than that reported by almost all other affected countries. Having verified the establishment of a new disease and identified the associated pathogen, the remaining key requirements of an epidemiological investigation, for a disease affecting production animals, are to describe how the disease spreads, describe the likely impacts of that disease at the individual and herd level and explore methods of disease control or mitigation.

Integrated parasite management (IPM) for pests, pathogens and parasites involves reducing or breaking transmission to reduce the impact of infection or infestation. For Theileria orientalis, the critical impact of infection is the first wave of parasitaemia from the virulent genotypes, Ikeda and Chitose, associated with the sequelae from the development of anaemia. Therefore, current control measures for T. orientalis advocate excluding the movement of naïve stock from non-endemic regions into infected areas and controlling the tick Haemaphysalislongicornis, the final host. In Australia, treatment of established infection is limited to supportive therapy. To update and expand these options, this review examines progress towards prevention and therapy for T. orientalis, which are key elements for inclusion in IPM measures to control this parasite.