A locus conferring tolerance to Theileria infection in African cattle.

East Coast fever, a tick-borne cattle disease caused by the Theileria parva parasite, is among the biggest natural killers of cattle in East Africa, leading to over 1 million deaths annually. Here we report on the genetic analysis of a cohort of Bos indicus (Boran) cattle demonstrating heritable tolerance to infection with T. parva (h2 = 0.65, s.e. 0.57). Through a linkage analysis we identify a 6 Mb genomic region on bovine chromosome 15 that is significantly associated with survival outcome following T. parva exposure. Testing this locus in an independent cohort of animals replicates this association with survival following T. parva infection. A stop gained variant in a paralogue of the FAF1 gene in this region was found to be highly associated with survival across both related and unrelated animals, with only one of the 20 homozygote carriers (T/T) of this change succumbing to the disease in contrast to 44 out of 97 animals homozygote for the reference allele (C/C). Consequently, we present a genetic locus linked to tolerance of one of Africa's most important cattle diseases, raising the promise of marker-assisted selection for cattle that are less susceptible to infection by T. parva.

Systematic Determination of TCR-Antigen and Peptide-MHC Binding Kinetics among Field Variants of a Theileria parva Polymorphic CTL Epitope.

CTLs are known to contribute to immunity toward Theileria parva, the causative agent of East Coast fever. The Tp967-75 CTL epitope from the Muguga strain of T. parva is polymorphic in other parasite strains. Identifying the amino acids important for MHC class I binding, as well as TCR recognition of epitopes, can allow the strategic selection of Ags to induce cellular immunity toward T. parva In this study, we characterized the amino acids important for MHC class I binding and TCR recognition in the Tp967-75 epitope using alanine scanning and a series of variant peptide sequences to probe these interactions. In a peptide-MHC class I binding assay, we found that the amino acids at positions 1, 2, and 3 were critical for binding to its restricting MHC class I molecule BoLA-1*023:01. With IFN-γ ELISPOT and peptide-MHC class I Tet staining assays on two parasite-specific bovine CTL lines, we showed that amino acids at positions 5-8 in the epitope were required for TCR recognition. Only two of eight naturally occurring polymorphic Tp9 epitopes were recognized by both CTLs. Finally, using a TCR avidity assay, we found that a higher TCR avidity was associated with a stronger functional response toward one of two variants recognized by the CTL. These data add to the growing knowledge on the cross-reactivity of epitope-specific CTLs and specificities that may be required in the selection of Ags in the design of a wide-spectrum vaccine for East Coast fever.

Investigation of Babesia spp. and Theileria spp. in ticks from Western China and identification of a novel genotype of Babesia caballi.

Babesia spp. and Theileria spp. are tick-borne protozoan parasites with veterinary importance. In China, epidemiological and genetic investigations on many Babesia and Theileria species were still absent in many areas and many tick species. From Aug 2021 to May 2023, 645 ticks were collected from the body surface of domestic animals (camels, goats, sheep, and cattle) using tweezers in seven counties in three provinces including Xinjiang (Qitai, Mulei, Hutubi, and Shihezi counties), Chongqing (Youyang and Yunyang counties), and Qinghai (Huangzhong county). Three tick species were morphologically and molecularly identified (334 Hyalomma asiaticum from Xinjiang, 245 Rhipicephalus microplus from Chongqing, and 66 Haemaphysalis qinghaiensis from Qinghai). A total of three Babesia species and two Theileria species were detected targeting the 18S gene. The COI and cytb sequences were also recovered from Babesia strains for further identification. In R. microplus from Chongqing, Babesia bigemina, the agent of bovine babesiosis, was detected. Notably, in H. asiaticum ticks from Xinjiang, a putative novel genotype of Babesia caballi was identified (0.90%, 3/334), whose COI and cytb genes have as low as 85.82% and 90.64-90.91% nucleotide identities to currently available sequences. It is noteworthy whether the sequence differences of its cytb contribute to the drug resistance of this variant due to the involvement of cytb in the drug resistance of Babesia. In addition, Theileria orientalis and Theileria annulata were detected in R. microplus from Chongqing (12.20%, 31/245) and H. asiaticum from Xinjiang (1.50%, 5/334), respectively. These results suggest that these protozoan parasites may be circulating in domestic animals in these areas. The pathogenicity of the novel genotype of B. caballi also warrants further investigation.

Molecular detection and characterization of Anaplasma ovis, Theileria ovis, and Theileria lestoquardi in sheep and goats in Luxor, Egypt.

BACKGROUND: Tick-borne diseases cause economically significant losses to animal production globally, and anaplasmosis and theileriosis are associated with the greatest losses. However, the spread of the relevant pathogens in flocks of domesticated animals in southern Egypt is little understood. Accordingly, in this study, we aimed to determine the prevalences of Anaplasma ovis, Theileria ovis, and Theileria lestoquardi in southern Egyptian sheep and goats through blood tests, and to make a molecular characterization of the A. ovis detected in sheep targeting a specific gene. RESULTS: We collected blood samples collected from 300 sheep and goats (n=150 /species) in Luxor Province in southern Egypt, and analyzed them for the presence of A. ovis, T. ovis and T. lestoquardi with screening by conventional and nested PCR targeting the msp4 and msp5, 18S rRNA, and merozoite surface protein genes. For A. ovis 140/300 samples (46.66%) were positive overall, with 90/150 (60%) and 50/150 (33.33%) positive samples in sheep and goats, respectively. Two major surface protein genes of A. ovis, msp4 and msp5, were sequenced using DNA extracted from sheep and goat blood samples, for phylogenetic analysis and genotyping. The msp4 gene sequence revealed no significant genetic diversity, to contrast to data on A. ovis strains from other countries. For T. lestoquardi, 8/150 (5.33%) samples were positive in sheep, but no samples were positive in goats (0%). For T. ovis, 32/150 (21.33%) samples were positive in sheep, but no samples were positive in goats (0%). Sequencing targeting the merozoite surface protein gene for T. lestoquardi and the small subunit ribosomal RNA gene for T. ovis revealed no significant genetic diversity in the study, another contrast to data on A. ovis strains from other countries. CONCLUSION: This study provides valuable data on phylogenetic and molecular classifications of A. ovis, T. ovis and T. lestoquardi found in southern Egyptian sheep and goats. It also represents the first report on detection and molecular characterization of T. lestoquardi in southern Egyptian sheep based on the specific merozoite surface protein gene, thus providing valuable data for molecular characterization of this pathogen in southern Egypt.

Unveiling genotypic diversity of Theileria orientalis in lethal outbreaks among bovines in Karnataka, India.

Theileria orientalis, the causal agent of oriental theileriosis, is known to cause mild disease in cattle and buffalo across the world. Recently, different genotypes of T. orientalis have emerged as pathogenic, causing high reported morbidity in cattle. This study focuses on investigating three suspected outbreaks of oriental theileriosis that resulted in fatalities among crossbred and indigenous bulls in Karnataka, India. Examination of blood smears revealed the presence of T. orientalis piroplasms within erythrocytes. The genetic characterization of T. orientalis was conducted by targeting specific markers, including the mpsp gene, p23 gene, and ribosomal DNA markers (18S rRNA gene, ITS-1, and ITS-2). Analysis based on the 18S rRNA gene unveiled the presence of both Type A and Type E genotypes of T. orientalis in the outbreaks. The mpsp gene-based analysis identified genotype 7 of T. orientalis in crossbred cows, whereas genotype 1 (Chitose B) was found to be present in indigenous bulls. Haplotype network analysis based on the mpsp gene revealed the presence of 39 distinct haplotypes within the 12 defined genotypes of T. orientalis with a high haplotype diversity of 0.9545 ± 0.017. Hematological and biochemical analysis revealed a decrease in calcium, hemoglobin levels, red blood cell counts, and phosphorus. This study constitutes the initial documentation of a clinical outbreak of oriental theileriosis in indigenous bulls with genotype 1 (Chitose 1B). Substantial epidemiological investigations are imperative to gain a comprehensive understanding of the geographical distribution of distinct genotypes and the diverse clinical manifestations of the disease across various hosts.

Expression profile of microRNAs in bovine lymphocytes infected with Theileria annulata and treated with buparvaquone.

Several miRNA-based studies on Theileria-transformed bovine cells have been conducted; however, the mechanism by which transformed cells exhibit uncontrolled proliferation is not yet fully understood. Therefore, it is necessary to screen more microRNAs that may play a role in the transformation process of host cells infected with Theileria annulata to better understand the transformation mechanisms of Theileria-infected cells. RNA sequencing was used to analyze miRNAs expression in the host bovine lymphocytes infected with T. annulata at different time points after buparvaquone (BW720) treatment and DMSO treatment (control groups). Differential miRNAs related to cell proliferation and apoptosis were identified through comparison with gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and a regulatory network of miRNA-mRNA was constructed. In total, 272 differentially expressed miRNAs were found at 36, 60 and 72 h. The miRNAs change of bta-miR-2285t, novel-miR-622, bta-miR-2478, and novel-miR-584 were significant. Analysis of 27 of these co-differential expressed miRNAs revealed that 15 miRNAs were down-regulated and 12 miRNAs were up-regulated. A further analysis of the changes in the expression of each of these 27 miRNAs in the three datasets suggested that bta-miR-2285t, bta-miR-345-5p, bta-miR-34a, bta-miR-150, and the novel-miR-1372 had significantly changed. Predicted target genes for these 27 miRNAs were analyzed by KEGG and the results demonstrated that EZR, RASSF, SOCS1 were mainly enriched in the signaling pathway microRNAs in cancer. MAPKAPK2, RELB, FLT3LG, and GADD45B were mainly enriched in the MAPK signaling pathway, and some genes were enriched in Axon guidance. This study has provided valuable information to further the understanding of the regulatory function of miRNAs in the host microenvironment and host-parasite interaction mechanisms.

The first study of the prevalence and genetic diversity of Theileria equi and Babesia caballi in horses in Russia.

Equine piroplasmosis (EP) is a global worldwide infection, which can lead to the death of animals. Despite the causative agents of EP being well studied, there are no data on the distribution and genetic characteristics of EP agents in any region of Russia. In this study, blood samples from 750 horses from Novosibirsk province, Irkutsk province, and Altai region of Russian Siberia were examined for the presence of EP agents. Theileria equi and Babesia caballi were detected in all examined regions, with mean prevalence rates of 60.4% and 7.2%, respectively. The identified pathogens were genetically characterized by the 18S rRNA gene. The determined T. equi sequences were highly conserved and belonged to genotypes A and E, with genotype E being found in 88.6% of genotyped samples. In contrast to T. equi, B. caballi sequences were genetically diverse. Seven sequence variants of B. caballi were identified, and only two of them matched known sequences from the GenBank database. The determined B. caballi sequences belonged to four distinct branches within genotype A. Mixed infections with several variants of B. caballi or with T. equi and B. caballi were common. The conducted phylogenetic analysis based on all available B. caballi sequences of the 18S rRNA gene (> 900 bp) from GenBank and from this study first demonstrated the presence of five monophyletic clusters within genotype A and three clusters within genotype B. Thus, the genetic study of B. caballi from Siberia has significantly expanded the data on the genetic diversity of this pathogen.

Molecular occurrence and genetic identification of Babesia spp. and Theileria spp. in naturally infected cattle from Thailand.

Piroplasm including Babesia spp. and Theileria spp. in cattle can cause illness that affects livestock productivity, resulting in significant production losses, especially in tropical and subtropical regions such as Thailand. This study aimed to investigate the prevalence of bovine piroplasms and to identify these blood parasites based on the 18S ribosomal RNA gene in cattle in the northeastern part of Thailand. Piroplasmid infections among beef and dairy cattle were examined using nested PCR. Furthermore, amplicon DNA was sequenced and analyzed, and a phylogenetic tree was constructed to determine the genetic diversity and relationships of the parasite in each area. A total of 141 out of 215 (65.6%) cattle were positive for infection with Babesia or Theileria. DNA analysis revealed that infection by Babesia bigemina, Babesia bovis, Theileria orientalis, Theileria sinensis, and Theileria sp. were common piroplasms in cattle in this region, with a high sequence shared identity and similarity with each other and clustered with isolates from other countries. This study provides information on the molecular epidemiology and genetic identification of Babesia spp. and Theileria spp. in beef and dairy cattle to provide a better understanding of piroplasm infection in cattle in this region, which will help control these blood parasites. Moreover, this is the first report identifying T. sinensis circulating among Thai cattle.

Microscopic and molecular investigation of vector borne haemoprotozoan diseases in dromedary camel of North Gujarat, India.

BACKGROUND OBJECTIVES: Vector-borne haemoprotozoan diseases comprise diverse group of single celled organism transmitted by haematophagus invertebrates. The current study was aimed at the identification of major haemoprotozoan (Babesia, Theileria and Trypanosoma) in dromedary camel of North Gujarat region in India using microscopy and Polymerase Chain Reaction (PCR). METHODS: A total of 234 blood samples were screened by the microscopic and molecular detection assays. Molecular prevalence studies of Theileria, Trypanosoma spp and Babesia was undertaken using 18s ribosomal DNA, RoTat 1.2 and SS rRNA gene respectively. The data relating to microscopic and molecular prevalence along with associated risk factors were analysed by statistical methods. RESULTS: The overall prevalence of hamoprotozoan disease based on microscopic and molecular investigation was 23.50%. The sensitivity and specificity (95% Confidence Interval) of PCR assay was 100% in comparison to microscopy (45.45 % sensitive and 100 % specific). The kappa coefficient between PCR and microscopy indicated good level of agreement with a value of 0.704 and SE of 0.159. INTERPRETATION CONCLUSION: Despite holding much significance to the animal sector, little work has been undertaken in regional parts of India regarding camel parasites. The present study offers first preliminary research data investigating haemoprotozoan disease using parasitological and molecular methods in camels in the region.

Molecular and immunological studies on Theileria equi and its vector in Egypt.

Equine piroplasmosis is not fully understood regarding pathogenicity, prophylaxis, host immune response expression, and specific vectors. Accurately identifying the parasite vector is crucial for developing an effective control plan for a particular infection. This study focused on morphologically identifying two Hyalomma species (H. anatolicum and H. marginatum) and one Rhipicephalus annulatus (R. annulatus) at the species level. The identification process was followed by phylogenetic analysis using the neighbor-joining method based on the cytochrome oxidase subunit 1 (COXI) gene as a specific vector for Theileria equi (T. equi) in horses. T. equi was diagnosed morphologically and molecularly from infected blood samples and crushed tick species using conventional PCR. Subsequently, phylogenetic analysis based on the amplification of the 18 S rRNA gene was conducted. The obtained sequence data were evaluated and registered in GenBank under accession numbers OR064161, OR067911, OR187727, and OR068139, representing the three tick species and the isolated T. equi, respectively. The study demonstrated that T. equi infection leads to immune system suppression by significantly increasing the levels of oxidative stress markers (CAT, GPx, MDA, and SOD) (P ≤ 0.0001), with this elevation being directly proportional to parasitemia levels in infected blood cells. Furthermore, a correlation was observed between parasitemia levels and the expression of immune response infection genes (IFN-gamma, TGF-ß1, and IL-1ß cytokines) in infected horses compared to non-infected equine. Common macroscopic symptoms indicating T. equi infection in horses include intermittent fever, enlarged lymph nodes (LN), and tick infestation.