Detection of Theileria sergenti infection in cattle by polymerase chain reaction amplification of parasite-specific DNA

Putative target sites in synganglion for novel ixodid tick control strategies

Acaricide resistance is a global problem that has impacts worldwide. Tick populations with broad resistance to all commercially available acaricides have been reported. Since resistance selection in ticks and their role in pathogen transmission to animals and humans result in important economic and public health burden, it is essential to develop new strategies for their control (i.e., novel chemical compounds, vaccines, biological control). The synganglion is the tick central nervous system and it is responsible for synthesizing and releasing signaling molecules with different physiological functions. Synganglion proteins are the targets of the majority of available acaricides. In this review we provide an overview of the mode-of-action and resistance mechanisms against neurotoxic acaricides in ticks, as well as putative target sites in synganglion, as a supporting tool to identify new target proteins and to develop new strategies for tick control.

Pathogenesis of Bronchopulmonary Dysplasia: Role of Oxidative Stress from 'Omics' Studies

Bronchopulmonary dysplasia (BPD) remains the most common respiratory complication of prematurity as younger and smaller infants are surviving beyond the immediate neonatal period. The recognition that oxidative stress (OS) plays a key role in BPD pathogenesis has been widely accepted since at least the 1980s. In this article, we examine the interplay between OS and genetic regulation and review 'omics' data related to OS in BPD. Data from animal models (largely models of hyperoxic lung injury) and from human studies are presented. Epigenetic and transcriptomic analyses have demonstrated several genes related to OS to be differentially expressed in murine models that mimic BPD as well as in premature infants at risk of BPD development and infants with established lung disease. Alterations in the genetic regulation of antioxidant enzymes is a common theme in these studies. Data from metabolomics and proteomics have also demonstrated the potential involvement of OS-related pathways in BPD. A limitation of many studies includes the difficulty of obtaining timely and appropriate samples from human patients. Additional 'omics' studies could further our understanding of the role of OS in BPD pathogenesis, which may prove beneficial for prevention and timely diagnosis, and aid in the development of targeted therapies.

Identification and isolation of pathogenic Theileria orientalis Ikeda genotype from confined dairy cattle, in Hebei, China

Theileria orientalis is known to be a group of benign cattle parasites with a cosmopolitan distribution, and has been classified into 11 genotypes through MPSP gene phylogenetic analysis. In China, T. orientalis is the most prevalent Theileria species, with several genotypes, but few fatal cases have been reported. In June 2020, dairy cattle in Zhangjiakou, Hebei Province, showed clinical symptoms of piroplasmosis, causing many animals to die. Blood smears and PCR detection results confirmed T. orientalis infection with a 66.7% positive rate of collected blood samples. The MPSP sequences analysis revealed parasite genotypes 1 (Chitose) and 2 (Ikeda). Aiming to isolate the pathogens, experimental animal was infected with T. orientalis via inoculation of the positive blood samples. The results has shown that only T. orientalis genotype 2 (Ikeda) was obtained that has confirmed by MPSP and 18S rRNA sequences analysis, indicating that the Ikeda type was predominant and responsible for the disease. Although many T. orientalis genotypes are present in China, the possibility of T. orientalis genotypes 1 and 2 infections in confined dairy cattle should be considered to avoid additional economic losses.

Pathogenesis of liver lesions in Theileria orientalis-inoculated cattle and severe combined immunodeficiency mice with bovine erythrocyte transfusion

Theileria orientalis (T. orientalis) is a bovine protozoal disease similar to malaria in humans. Although the common outcome of malaria in humans and T. orientalis infection in cattle is hepatic disorder, the mechanisms of its development remain unknown. In this study, we investigated hepatocyte injury characterized by accumulation of macrophages with ingested erythrocytes in sinusoid and extramedullary hematopoiesis in cattle and mice experimentally infected with T. orientalis (T. orientalis-infected cattle and T. orientalis-infected mice). Vacuolization of hepatic cells was frequently observed in the vicinity of the aggregated macrophages in the liver sinusoids of T. orientalis-infected mice. A significant percentage of the macrophages accumulated in the liver sinusoids of the severely infected cattle and mice (14.6% and 24.2 to 53.2%, respectively) reacted positively with interleukin-1, interleukin-6 and TNF-α antibodies. Increase in the production of these cytokines was confirmed in T. orientalis-infected cattle and mice by real-time RT-PCR. These findings strongly suggest that increased cytokine production by the macrophages that have phagocytosed T. orientalis-infected erythrocytes causes hepatic disorder in T. orientalis-infected animals.

An appraisal of oriental theileriosis and the Theileria orientalis complex, with an emphasis on diagnosis and genetic characterisation

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.

Endemic, exotic and novel apicomplexan parasites detected during a national study of ticks from companion animals in Australia

BACKGROUND

Apicomplexan tick-borne pathogens that cause disease in companion animals include species of Babesia Starcovici, 1893, Cytauxzoon Neitz & Thomas, 1948, Hepatozoon Miller, 1908 and Theileria Bettencourt, Franca & Borges, 1907. The only apicomplexan tick-borne disease of companion animals that is known to occur in Australia is babesiosis, caused by Babesia canis vogeli Reichenow, 1937 and Babesia gibsoni Patton, 1910. However, no molecular investigations have widely investigated members of Apicomplexa Levine, 1980 in Australian ticks that parasitise dogs, cats or horses, until this present investigation.

RESULTS

Ticks (n = 711) removed from dogs (n = 498), cats (n = 139) and horses (n = 74) throughout Australia were screened for piroplasms and Hepatozoon spp. using conventional PCR and Sanger sequencing. The tick-borne pathogen B. vogeli was identified in two Rhipicephalus sanguineus Latreille ticks from dogs residing in the Northern Territory and Queensland (QLD). Theileria orientalis Yakimov & Sudachenkov, 1931 genotype Ikeda was detected in three Haemaphysalis longicornis Neumann ticks from dogs in New South Wales. Unexpectedly, the exotic tick-borne pathogen Hepatozoon canis James, 1905 was identified in an Ixodes holocyclus Neumann tick from a dog in QLD. Eight novel piroplasm and Hepatozoon species were identified and described in native ticks and named as follows: Babesia lohae n. sp., Babesia mackerrasorum n. sp., Hepatozoon banethi n. sp., Hepatozoon ewingi n. sp., Theileria apogeana n. sp., Theileria palmeri n. sp., Theileria paparinii n. sp. and Theileria worthingtonorum n. sp. Additionally, a novel cf. Sarcocystidae sp. sequence was obtained from Ixodes tasmani Neumann but could not be confidently identified at the genus level.

CONCLUSIONS

Novel species of parasites in ticks represent an unknown threat to the health of companion animals that are bitten by these native tick species. The vector potential of Australian ticks for the newly discovered apicomplexans needs to be assessed, and further clinical and molecular investigations of these parasites, particularly in blood samples from dogs, cats and horses, is required to determine their potential for pathogenicity.

Evaluating an indirect rMPSP enzyme-linked immunosorbent assay for the detection of bovine Theileria infection in China

Bovine theileriosis, a tick-borne protozoan disease caused by Theileria annulata, Theileria orientalis and Theileria sinensis, is widespread in China and is a serious economic problem for the Chinese livestock industry. In this study, recombinant major piroplasma surface proteins (MPSP) of T. annulata, T. orientalis and T. sinensis based on MPSP genes were expressed in Escherichia coli BL21(DE3). The immunogenicity and specificity of the three purified recombinant MPSP proteins were evaluated with the reference positive sera of T. annulata, T. orientalis, T. sinensis, Babesia bovis, B abesia bigemina, Babesia major, Babesia motasi, Theileria luwenshuni, Theileria uilenbergi and Anaplasma ovis using an enzyme-linked immunosorbent assay (ELISA) or western blotting. The results showed that all three of the rMPSP proteins had a strong reaction with the sera from cattle infected with T. annulata, T. orientalis and T. sinensis via western blotting but not with other piroplasma and Anaplasma species. Then, the rMPSP protein of T. sinensis was used to develop an iELISA for detecting the three Theileria species infections. The specificity and sensitivity were 95.7 and 95.5 %, respectively, with a threshold of 28.8 % of the specific mean antibody rate (AbR). Finally, 2473 field-collected bovine sera, from 42 prefectures of 17 provinces in China, were tested using the ELISA to evaluate the prevalence of bovine theileriosis, and the average positive rate was 43.6 %. The developed iELISA could be a suitable tool to detect the three bovine Theileria species, and the data also provided important information regarding the current prevalence of bovine theileriosis in China.

Dynamics of Theileria orientalis genotype population in cattle in a year-round grazing system

Theirelia orientalis is a tick-borne haemoprotozoan parasite, and infection with this parasite is one of the most important diseases for grazing cattle. Co-infection of cattle with different genotypes of T. orientalis often occurs. In this study, we investigated the temporal dynamics of genotypes in cattle in a year-round grazing system in Japan. Genotype-specific PCR assays to determine major piroplasm surface protein (MPSP) genotypes (types 1 to 5) of T. orientalis were performed by using time-course blood samples collected from grazing cattle and ticks in a pasture. All 20 cattle investigated in this study were infected with T. orientalis. By using genotype-specific PCR, we detected the combination of genotypes of T. orientalis (types 1 to 5) from each cattle. These multiple genotypes of T. orientalis were also confirmed in ticks. Notably, each genotype of T. orientalis in cattle was temporally detected from cattle and more variable genotypes were found in summer. The observed temporal dynamics of the MPSP genotypes of T. orientalis in cattle could be explained by host immunity against the parasites or genetic recombination of parasite in ticks.

FatalTheileria orientalisN2 genotype infection among Asian water buffaloes (Bubalus bubalis) in a commercial dairy farm in Kerala, India

Fifteen dairy buffaloes of a farm in the state of Kerala, India developed fatal oriental theileriosis within 2 months of their procurement. Typical piroplasms ofTheileria orientaliswere observed in the erythrocytes of all affected animals by Giemsa–Leishman staining of blood smears. Case fatality rate was 87·5% (seven out of eight) in the clinically progressed cases. Therapeutic management with anti-theilerial drugs buparvaquone and oxytetracycline led to recovery of seven other animals in less advanced stages of the disease. The aim of this study was to determine the reasons for increased virulence of this pathogen, hitherto considered to be benign. Acute haemolytic anaemia was the predominant haematological finding in the affected animals. Lymphocytic infiltration and degeneration of vital organs leading to functional derangement was the cause of the high mortality. Identification ofT. orientaliswas confirmed by polymerase chain reaction (PCR). DNA sequencing of the PCR products revealed close identity with already reported sequences ofT. orientalis/buffeliN2 genotype. The sequences were deposited in GenBank with accession number KM609973 and KM043772.Rhipicephalusticks, previously not reported as vectors for oriental theileriosis, were identified as the potential vectors. This is the first report of fatal oriental theileriosis in Asian water buffaloes.

Development of a multiplex PCR assay for detection and discrimination of Theileria annulata and Theileria sergenti in cattle

Aim to construct a simple and efficient diagnostic assay for Theileria annulata and Theileria sergenti, a multiplex polymerase chain reaction (PCR) method was developed in this study. Following the alignment of the related sequences, two primer sets were designed specific targeting on T. annulata cytochrome b (COB) gene and T. sergenti internal transcribed spacer (ITS) sequences. It was found that the designed primers could react in one PCR system and generating amplifications of 818 and 393 base pair for T. sergenti and T. annulata, respectively. The standard genomic DNA of both species Theileria was serial tenfold diluted for testing the sensitivity, while specificity test confirmed both primer sets have no cross-reaction with other Theileria and Babesia species. In addition, 378 field samples were used for evaluation of the utility of the multiplex PCR assay for detection of the pathogens infection. The detection results were compared with the other two published PCR methods which targeting on T. annulata COB gene and T. sergenti major piroplasm surface protein (MPSP) gene, respectively. The developed multiplex PCR assay has similar efficient detection with COB and MPSP PCR, which indicates this multiplex PCR may be a valuable assay for the epidemiological studies for T. annulata and T. sergenti.

Use of multiplexed tandem PCR to estimate the prevalence and intensity of Theileria orientalis infections in cattle

This study employed a semi-quantitative, multiplexed tandem PCR (MT-PCR) to assess the prevalence and infection intensity of four genotypes (buffeli, chitose, ikeda and type 5) of Theileria orientalis in cattle in Australia. Genomic DNA samples from blood samples (n=448) collected from 27 to 32 dairy cows from each of 15 dairy herds with a history of recent theileriosis outbreaks (Group 1), and from blood samples available from 24 cows with or without oriental theileriosis (Group 2) were tested using MT-PCR. Results revealed that all four genotypes were present in Group 1 cattle; genotype buffeli had the highest prevalence (80.5%), followed by genotypes ikeda (71.4%), chitose (38.6%) and type 5 (20.3%). Genotype ikeda had the highest average infection intensity in the cattle (relating to 55,277 DNA copies), followed by buffeli, chitose and type 5 (6354-51,648 copies). For Group 2, results indicated that genotype ikeda had a significantly higher average intensity of infection than buffeli in symptomatic cattle (P<0.001), and symptomatic cattle had a higher intensity of ikeda than asymptomatic cattle (P=0.004). Future studies should assess the utility of the present MT-PCR assay as a diagnostic and epidemiological tool in other parts of Australasia and the world.

Development and validation of a quantitative PCR assay using multiplexed hydrolysis probes for detection and quantification of Theileria orientalis isolates and differentiation of clinically relevant subtypes

Theileria orientalis is an emerging pathogen of cattle in Asia, Australia, and New Zealand. This organism is a vector-borne hemoprotozoan that causes clinical disease characterized by anemia, abortion, and death, as well as persistent subclinical infections. Molecular methods of diagnosis are preferred due to their sensitivity and utility in differentiating between pathogenic and apathogenic genotypes. Conventional PCR (cPCR) assays for T. orientalis detection and typing are laborious and do not provide an estimate of parasite load. Current real-time PCR assays cannot differentiate between clinically relevant and benign genotypes or are only semiquantitative without a defined clinical threshold. Here, we developed and validated a hydrolysis probe quantitative PCR (qPCR) assay which universally detects and quantifies T. orientalis and identifies the clinically associated Ikeda and Chitose genotypes (UIC assay). Comparison of the UIC assay results with previously validated universal and genotype-specific cPCR results demonstrated that qPCR detects and differentiates T. orientalis with high sensitivity and specificiy. Comparison of quantitative results based on percent parasitemia, determined via blood film analysis and packed cell volume (PCV) revealed significant positive and negative correlations, respectively. One-way analysis of variance (ANOVA) indicated that blood samples from animals with clinical signs of disease contained statistically higher concentrations of T. orientalis DNA than animals with subclinical infections. We propose clinical thresholds to assist in classifying high-, moderate-, and low-level infections and describe how parasite load and the presence of the Ikeda and Chitose genotypes relate to disease.

A review of Theileria diagnostics and epidemiology

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Serological and molecular assays exist for most economic important Theileria species.

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Molecular assays are constantly being improved with regard to sensitivity and specificity.

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The concept of what constitute a Theileria species impacts on accurate diagnostics.

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Analytical specificity of molecular assays are >800 000 parasites/L blood.

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Parasitemia ranges may determine practical limits of detection.

An extensive range of serological and molecular diagnostic assays exist for most of the economically important Theileira species such as T. annulata, T. equi, T. lestoquardi, T. parva, T. uilenbergi and other more benign species. Diagnostics of Theileria is considered with regard to sensitivity and specificity of current molecular and serological assays and their use in epidemiology. In the case of serological assays, cross-reactivity of genetically closely related species reduces the use of the gold standard indirect fluorescent antibody test (IFAT). Development of antigen-specific assays does not necessarily address this problem, since closely related species will potentially have similar antigens. Even so, serological assays remain an important line of enquiry in epidemiological surveys. Molecular based assays have exploded in the last decade with significant improvements in sensitivity and specificity. In this review, the current interpretation of what constitute a species in Theileria and its impact on accurate molecular diagnostics is considered. Most molecular assays based on conventional or real-time PCR technology have proven to be on standard with regard to analytical sensitivity. However, consideration of the limits of detection in regard to total blood volume of an animal indicates that most assays may only detect >400,000 parasites/L blood. Even so, natural parasitaemia distribution in carrier-state animals seems to be above this limit of detection, suggesting that most molecular assays should be able to detect the majority of infected individuals under endemic conditions. The potential for false-negative results can, however, only be assessed within the biological context of the parasite within its vertebrate host, i.e. parasitaemia range in the carrier-state that will support infection of the vector and subsequent transmission.

Semiquantitative multiplexed tandem PCR for detection and differentiation of four Theileria orientalis genotypes in cattle

Oriental theileriosis is an emerging, tick-borne disease of bovines in the Asia-Pacific region and is caused by one or more genotypes of the Theileria orientalis complex. This study aimed to establish and validate a multiplexed tandem PCR (MT-PCR) assay using three distinct markers (major piroplasm surface protein, 23-kDa piroplasm membrane protein, and the first internal transcribed spacer of nuclear DNA), for the simultaneous detection and semiquantification of four genotypes (Buffeli, Chitose, Ikeda, and type 5) of the T. orientalis complex. Analytical specificity, analytical sensitivity, and repeatability of the established MT-PCR assay were assessed in a series of experiments. Subsequently, the assay was evaluated using 200 genomic DNA samples collected from cattle from farms on which oriental theileriosis outbreaks had occurred, and 110 samples from a region where no outbreaks had been reported. The results showed the MT-PCR assay specifically and reproducibly detected the expected genotypes (i.e., genotypes Buffeli, Chitose, Ikeda, and type 5) of the T. orientalis complex, reliably differentiated them, and was able to detect as little as 1 fg of genomic DNA from each genotype. The diagnostic specificity and sensitivity of the MT-PCR were estimated at 94.0% and 98.8%, respectively. The MT-PCR assay established here is a practical and effective diagnostic tool for the four main genotypes of T. orientalis complex in Australia and should assist studies of the epidemiology and pathophysiology of oriental theileriosis in the Asia-Pacific region.

Molecular prevalence and genetic diversity of bovine Theileria orientalis in Myanmar

Theileria orientalis is a causative agent of benign theileriosis in cattle and distributed in mainly Asian countries. In the present study, we examined the prevalence of T. orientalis infection by PCR based on the major piroplasm surface protein gene (MPSP) sequences in cattle in Myanmar, followed by phylogenetic analysis of the MPSP genes. The MPSP gene was amplified in 258 of 713 (36.2%) cattle blood DNA samples collected from five cities in different geographical regions of Myanmar. Phylogenetic analysis of MPSP sequences from 54 T. orientalis-positive DNA samples revealed the presence of six allelic genotypes, including Types 1, 3, 4, 5, 7, and N-3. Types 5 and 7 were the predominant types detected. Sequences of the MPSP genes detected in Myanmar were closely related to those from Thailand, Vietnam or Mongolia. These findings suggest that movement of animals carrying T. orientalis parasites between Southeast Asian countries could be a reason for the similar genotype distribution of the parasites in Myanmar.

Observation of a novel Babesia spp. in Eastern Grey Kangaroos (Macropus giganteus) in Australia

The roles and epidemiological features of tick-borne protozoans are not well elicited in wildlife. Babesia spp. are documented in many domestic animals, including cattle, horses, pigs, dogs and cats. Three cases affecting eastern grey kangaroos are described. The kangaroos exhibited neurological signs, depression and marked anaemia, and microscopic examination of blood smears revealed intraerythrocytic piroplasms. One to seven intraerythrocytic spherical, oval, pyriform and irregularly-shaped parasites consistent with Babesia spp. were seen in the blood smears and the percentage of infected erythrocytes was estimated to be approximately 7% in each case. Data suggest that the tick vector for this kangaroo Babesia sp. is a Haemaphysalis species. For Case 2, ultrastructural examination of the erythrocytes of the renal capillaries showed parasites resembling Babesia spp. and 18 of 33 erythrocytes were infected. DNA sequencing of the amplified 18S rDNA confirmed that the observed intraerythrocytic piroplasms belong to the genus Babesia. The phylogenetic position of this new kangaroo Babesia sp. (de novo Babesia macropus), as a sister species to the new Australian woylie Babesia sp., suggests a close affinity to the described Afro–Eurasian species Babesia orientalis and Babesia occultans suggesting perhaps a common ancestor for the Babesia in kangaroos.

PCR detection of Babesia ovata from cattle reared in Japan and clinical significance of coinfection with Theileria orientalis

We describe here the clinical significance of coinfection with Theileria orientalis and Babesia ovata in cattle. Anemia status in a herd of dairy cattle in Japan was investigated in relation to infection with these parasites. Our findings indicate that while B. ovata infection might not be the primary cause of anemia in the cattle, it may contribute to the clinical development of anemia in animals coinfected with both B. ovata and T. orientalis.

Molecular characterization of Theileria orientalis causing fatal infection in crossbred adult bovines of South India

The disease condition attributed to have been caused by Theileria orientalis is generally benign. However, it is also thought that the parasite, at least some strains of it, can cause fatal disease. The present communication deals with the clinical signs, postmortem lesions and diagnosis of a fatal disease due to T. orientalis which caused mortality in crossbred adult bovines of South India. High body temperature, lacrimation, nasal discharge, swollen lymph nodes and haemoglobinuria were the symptoms observed. The postmortem lesions observed were punched out ulcers in abomasum, enlargement of spleen, massive pulmonary oedema, frothy exudates in trachea, epicardial and endocardial haemorrhage and haemorrhagic duodenitis. Peripheral blood smear examination revealed rod shaped Theileria sp. organisms. Polymerase chain reaction that amplify the T. orientalis specific P(32/33) gene, followed by cloning and sequencing, revealed maximum homology with Narathiwat (Thailand) and Jingole -1 (Indonesia) isolates which were positioned as isolate type 7 of T. orientalis.

Epidemiological survey of Theileria parasite infection of cattle in Northeast China by allele-specific PCR

An epidemiological survey on a Theileria parasite infection of cattle in Northeast China was carried out using allele-specific PCR and DNA sequence analysis of the major piroplasm surface protein (MPSP) gene. The results showed that 14 of 104 blood samples were positive for Theileria by PCR. Among the positive cases, co-infection with various combinations of C- and I-type parasites was detected in 12 samples; no B- and Thai-type parasites were detected by allele-specific PCR. Phylogenetic analysis based on the MPSP gene sequences revealed that Theileria parasites with the MPSP types 1, 2, and 4 were distributed in Northeast China.

Rapid discrimination and quantification of Theileria orientalis types using ribosomal DNA internal transcribed spacers

We report the population structure analysis of Theileria orientalis types (Ikeda, Buffeli and Chitose), the causative agent of theileriosis in cattle and its cohorts, using ITS1 and ITS2 spacers by fragment genotyping. We utilized primers flanking the two ribosomal RNA internal transcribed spacers (ITS1 and ITS2). Due to varying degrees of sequence polymorphism in the ITS regions found within and between species, we exploited the insertions and or deletions in these regions which resulted in different fragment sizes. On the basis of fragment size polymorphism, we could discriminate the three commonly found types of T. orientalis. ITS1 was capable of discriminating all three types (Ikeda-251 bp, Chitose-274 bp and Buffeli-269 bp) in one single reaction by fragment genotyping. In contrast, using ITS2, Ikeda (133-bp) a more pathogenic type was distinguishable from Buffeli/Chitose (139-bp). When compared with previous PCR detection method using, ITS1 and ITS2 genotyping was found to be more sensitive method with high specificity in population analysis and can be deployed in molecular epidemiology studies.

Polymorphism analysis of Chinese Theileria sergenti using allele-specific polymerase chain reaction of the major piroplasm surface protein gene

Theileria sergenti is a tick-borne parasite found in many parts of the world. The major piroplasm surface protein (MPSP), a conserved protein in all Theileria species, has been used as a marker for epidemiological and phylogenetic studies of benign Theileria species. In this study, Chinese species of T. sergenti were characterized by allele-specific polymerase chain reaction (PCR) and DNA sequence analysis of the MPSP gene. Using universal or allele-specific primer sets for PCR amplification of the MPSP gene, 98 of 288 cattle blood samples, collected from 6 provinces in China, were found to be positive. Among the positive samples, only 3 allelic MPSP gene types (Chitose [C]-, Ikeda [I]-, and buffeli [B]-type) were successfully amplified. Moreover, the results revealed that the majority of the parasites sampled in this study were C- and I-type (prevalence of 84 and 69%, respectively), whereas the B-type was less common (prevalence of 36%). Co-infections with C-, I-, and B-type T. sergenti also were found. An additional known allele, Thai-type, was not detected. Phylogenetic analysis based on the MPSP gene sequences, including 3 standard stocks generated in the laboratory ( T. sergenti Wenchuan, T. sergenti Ningxian, and T. sergenti Liaoyang), revealed that the isolates of Chinese sergenti were comprised of at least 4 allelic MPSP gene types, i.e., C-, I-, B1-, and B2-type, and these parasites with 6 MPSP types 1-5 and 7 were present in China.

Detecting and differentiating Theileria sergenti and Theileria sinensis in cattle and yaks by PCR based on major piroplasm surface protein (MPSP)

Theileria sergenti and Theileria sinensis are closely related members of benign Theileria species found in cattle and yaks in China. They are morphologically indistinguishable. A polymerase chain reaction (PCR) targeting major piroplasm surface protein of T. sergenti and T. sinensis was developed in this study. The newly developed oligonucleotide primer set was able to specifically amplify the DNA of T. sinensis and in conjunction with primers for T. sergenti and these two species could be detected and distinguished. Specificity testing also revealed that there was no cross-reaction with the other tick-borne diseases Theileria annulata, Babesia ovata, Anaplasma marginale as well as bovine white blood cells. Phylogenetic analysis based on the MPSP gene sequences confirmed the specificity of PCR assays. The sensitivity of the methods was 0.1pg DNA for the T. sergenti PCR and 1pg DNA for T. sinensis PCR. Two hundred and thirty-six field blood samples from of cattle and yaks were collected from five different geographical regions in China where benign Theileria species have been found. T. sergenti was found in all five provinces but was absent from one county in Gansu Province. T. sinensis was only found in Gansu Province. In both counties in Gansu where the parasites co-existed, mixed infections were detected. Our results indicate that the PCR methods developed in this study are suitable for the detection and differentiation of T. sergenti and T. sinensis.

A molecular phylogeny of the benign Theileria parasites based on major piroplasm surface protein (MPSP) gene sequences

To investigate the phylogeny of benign Theileria parasites, we determined the complete major piroplasm surface protein (MPSP) gene sequences for 6 benign theilerial organisms, including the first from tick. Sequences were analysed alongside published sequences for 39 benign Theileria parasites, using Bayesian inference and maximum parsimony. All MPSP sequences were 852 nucleotides, except for Gansu, Wuchangbuf, VB01, and VB01; Gansu contained 873 nucleotides, and the other 3 had 855. Deduced amino acid sequences contained 284 residues, except for Gansu (291) and Wuchangbuf, VB01, and VB01 (285 each). Pairwise comparisons showed identities among 45 theilerial MPSP sequences ranging from 70.9 to 99.8% for nucleotide and 71.0 to 100% for amino acid sequences. Our results clearly indicate that all global parasites, excluding Brisbane, were classified into 1 of 8 types; 6 types of Theileria exist in Korea. Each type, excluding Type 6, has several type-specific amino acid sequences. The phylogenetic tree derived from the nucleotide sequences showed 2 sister-group relationships, Type 2+Type 7 and Type 3+Brisbane, with a new branching pattern: (Type 6 (Type 8 ((Type 2, Type 7), (Type 1, (Type 4, (Type 5, (Type 3, Brisbane))))))). Our sequence data showed no geographical influence on worldwide Theileria parasite distribution.

Epidemiological survey of Theileria orientalis infection in grazing cattle in the eastern part of Hokkaido, Japan

Theileria orientalis is one of the benign species of Theileria that is widely distributed in Japan and is sometimes responsible for serious economic losses in the livestock industry. In the present study, we surveyed the current status of T. orientalis infection in grazing cattle in the eastern areas of Hokkaido (Taiki, Otofuke, Shintoku, and Shin-Hidaka districts) using molecular methods, as well as traditional methods, of diagnosis. The genes encoding the major piroplasm surface protein (MPSP) and p23 of T. orientalis were identified using highly detectable polymerase chain reaction (PCR). Results of the MPSP-PCR assay indicated that grazing cattle in these districts, after about 1.5 months pasturage, showed high rates of infection, ranging from 10.0-64.8%. Although the main MPSP and p23 genotypes detected were the Ikeda- or Chitose-types, an MPSP gene closely relating to that found in Okinawa prefecture, and a p23 gene closely relating to the Australian (Warwick) Buffeli-type gene, were found in the cattle in Shintoku and Shin-Hidaka districts. The present survey indicated that there were at least five types of T. orientalis classified by their MPSP genes in Hokkaido, Japan, and that T. orientalis infection rates are still high in this region.

A molecular survey of bovine Theileria parasites among apparently healthy cattle and with a note on the distribution of ticks in eastern Turkey

A survey of Theileria parasites in cattle in eastern Turkey was carried out using specific polymerase chain reaction. A total of 252 blood samples were collected from clinically healthy cattle between June and July 2004. Of 252 blood samples examined, 41 (16%) were positive for piroplasms by microscopy, whereas 114 (45%) were positive for the presence of at least one species of Theileria by PCR. The percentages of positive animals for Theileria annulata and benign Theileria species (Theileria sergenti/buffeli/orientalis) were 39% (99/252) and 7% (18/252), respectively. By allele-specific PCR examination of 18 field isolates which were positive for benign Theileria parasites, 8 samples were only amplified by B-type specific primers and 10 samples were amplified by both of the B and C-type specific primers, indicating a mixed infection with B and C-type of the parasite. None of the field isolates was amplified by I-type specific primers. Three samples were co-infected with T. annulata and benign Theileria parasites. Two of them which were infected with B-type parasite were also infected with T. annulata, the other sample which was infected both of B and C-type parasites was also infected with T. annulata. A total of 724 ixodid ticks were collected from the cattle. Hyalomma anatolicum anatolicum was the dominant species with 32% (230/724) in the region. H. a. excavatum, Boophylus annulatus and Rhipicephalus bursa represented 25% (183/724), 19% (140/724) and 15% (112/724) of the total number of ticks, respectively. R. sanguineus was the minor species and represented 8% (59/724) of the tick population.

Genetic Diversity of Benign Theileria Parasites of Cattle in the Okinawa Prefecture

Benign Theileria parasites of cattle distributed in the Okinawa prefecture were characterized by allele-specific polymerase chain reaction (PCR) and DNA sequence analysis of the major piroplasm surface protein (MPSP) gene. Using universal or allele-specific primer sets, parasite DNA was amplified in 31 out of 48 blood samples obtained from beef cattle. Among the positive cases, mixed infections involving various combinations of I-, C-, and B-type parasites were detected in 24 (77.4%) samples. Phylogenetic analysis based on the MPSP gene sequences revealed that parasites with the MPSP types 1-5 and 7, exist within the Okinawa prefecture.

Molecular epidemiological survey of benign Theileria parasites of cattle in Japan: detection of a new type of major piroplasm surface protein gene

Benign Theileria species of cattle are found in most parts of the world. The major piroplasm surface protein (MPSP), a conserved protein in all Theileria species, has been used as a maker for epidemiological and phylogenetical studies of benign Theileria species. Parasites with Ikeda- or Chitose-type MPSP genes are dominant in Japan, but we report here mixed infection cases of Theileria parasites with an additional MPSP type parasite infecting cattle in Abashiri District, Hokkaido. The MPSP gene sequence found in the additional type was closely related to MPSP genes of Theileria parasites found in Southeast Asian countries, including Thailand (Narathiwat) and Indonesia (Java). Theileria parasites from the blood sample were also distinguishable from the Ikeda or Chitose type parasites by the small subunit (SSU) rRNA gene sequence analysis, and they are grouped into the SSU rRNA types C/D found in Korea, North America, and Spain. The present finding of mixed infections of cattle with three different types of Theileria makes epidemiological feature of bovine theileriosis in Japan more complex. We have designed a set of primers specific to this MPSP type in order to conduct further epidemiological study.

Verification by polymerase chain reaction of vertical transmission of Theileria sergenti in cows

To evaluate the transplacental transfer of Theileria sergenti infection in cattle, we used DNA probes to detect T. sergenti in 6 pregnant cows and their calves. All the animals were monitored by parasitologic, serologic, and polymerase chain reaction (PCR) assays for a predicted 875-base-pair (bp) DNA product and a 684-bp amplicon detected by nested PCR in the blood and spleens of aborted fetuses. An open reading frame (ORF) starting at nucleotide 170 and terminating at position 1021 was shown to code for a polypeptide of 283 amino acid residues. All 6 dams and 5 calves were positive for T. sergenti in all tests. One calf was positive only with nested PCR. We conclude that transplacental transmission of T. sergenti is a significant problem. The relevance of the data in the programmed introduction of new (especially pregnant) animals into established clean herds needs serious consideration with regard to control of theileriosis and other tickborne diseases.

Survey of Theileria parasite infection in cattle in Cambodia and Vietnam using piroplasm surface protein gene-specific polymerase chain reaction

A survey of Theileria parasite infection in cattle in Cambodia and Vietnam was carried out by using allele-specific polymerase chain reaction. A total of 137 blood samples from draught animals in Cambodia and 40 blood samples from dairy cattle in Vietnam were analyzed. In Cambodia, 69 out of 137(50.4%) samples were PCR-positive containing mainly the Thai and the C type parasites. In Vietnam, 11 (27.5%) samples were positive and all were of the Thai type parasite.

Development of a polymerase chain reaction method for diagnosing Babesia gibsoni infection in dogs

A pair of oligonucleotide primers were designed according to the nucleotide sequence of the P18 gene of Babesia gibsoni (B. gibsoni), NRCPD strain, and were used to detect parasite DNA from blood samples of B. gibsoni-infected dogs by polymerase chain reaction (PCR). PCR was specific for B. gibsoni since no amplification was detected with DNA from B. Canis or normal dog leucocytes. PCR was sensitive enough to detect parasite DNA from 2.5 microl of blood samples with a parasitemia of 0.000002%. PCR detected parasite DNA from 2 to 222 days post-infection in sequential blood samples derived from a dog experimentally infected with B. gibsoni. The detection of B. gibsoni DNA by PCR was much earlier than the detection of antibodies to B. gibsoni in blood samples by the indirect fluorescent antibody test (IFAT) or that of the parasite itself in Giemsa-stained thin blood smear film examined by microscopy. In addition, 28 field samples collected from dogs in Kansai area, Japan, were tested for B. gibsoni infection. Nine samples were positive in blood smears, 9 samples were positive by IFAT and 11 samples were positive for B. gibsoni DNA by PCR. The nucleotide sequences of PCR products from all 11 samples found positive by PCR were completely identical to that of the P18 gene of the B. gibsoni, NRCPD strain. These results suggest that PCR provides a useful diagnostic tool for the detection of B. gibsoni infection in dogs.

Bovine piroplasms in Minorca (Balearic Islands, Spain): a comparison of PCR-based and light microscopy detection

The present study provides the first epidemiological data regarding infection by Theileria and Babesia piroplasms in cattle in Minorca. More than 94% of the studied animals were positive for the presence of Theileria sp., and of those, 41.3% were positive for the presence of Theileria annulata. These results indicate that the prevalence of Mediterranean theileriosis caused by T. annulata is very high in Minorcan dairy farms and that other Theileria sp. are also present in the area. The prevalence of infection was similar throughout the study indicating an endemic situation in this island. The use of PCR resulted in significantly higher efficacy of detection of Theileria sp. compared to microscopical observation (MO) of blood smears and allowed the specific discrimination between pathogenic and non-pathogenic theilerias which cannot be accomplished by traditional diagnosis by MO. Babesia infection in the area was mainly due to Babesia bigemina (6.0% of the studied animals were infected), while one animal (0.75%) was found to be infected by Babesia bovis. It was observed that 31% of animals infected with B. bigemina had a concurrent infection of T. annulata. PCR also resulted in a significantly higher efficacy of detection of Babesia sp. compared to MO when infection levels were higher, towards the end of the study period. The results clearly demonstrate that parasitic infection by piroplasms, especially Theileria sp. is common and endemic in the island of Minorca and that PCR is the optimal approach for the detection and discrimination of these important parasites.

Molecular characterisation of the Theileria buffeli/orientalis group

Benign bovine Theileria parasites known as either Theileria buffeli, Theileria orientalis or Theileria sergenti are classified on basis of their morphology, vector specificity, pathogenicity and 18S small subunit ribosomal RNA or major piroplasm protein (MPSP) sequences. Since most isolates have been characterized on only some of these criteria and the existing confusion in nomenclature, an analysis was performed on eight different isolates to combine 18S rRNA data with MPSP data and the results were compared with available biological parameters. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach for both genes was used in combination with reverse line blot hybridisation for the 18S rRNA gene. Both MPSP and 18S rRNA genes were cloned and sequenced from parasites displaying aberrant MPSP RFLP profiles. Phylogeny based on published and determined 18S rRNA and MPSP sequences did correlate within the same isolate but there was no obvious correlation between molecular and biological data. Based on these findings, we suggest that the appropriate name for all these parasites is Theileria buffeli. A more specific nomenclature should be assigned when new molecular markers may become available.

Immunity and vaccine development in the bovine theilerioses

There are three economically important bovine Theileria species: Theileria annulata, which causes tropical theileriosis and occurs across north Africa and most of central Asia; Theileria parva, which causes East Coast fever and is found in East and Central Africa; and Theileria sergenti, which is predominantly a problem in Japan and Korea. Theileria annulata preferentially infects macrophages in vivo. It is controlled largely by means of live, attenuated vaccines, which are produced by prolonged tissue culture of the schizont-infected cells. The immunity induced in animals, which have either recovered from an infection or have been vaccinated (with an attenuated vaccine), is broad, solid and cell mediated. It is considered that the main effector cells are cytostatic macrophages that produce nitric oxide. Subsidiary roles for bovine leucocyte antigen (BoLA)-restricted, transiently appearing, cytotoxic T cells, and possibly also natural killer (NK) cells, have been identified. Cytokines such as tumour necrosis factor alpha (TNF-alpha) may have important roles, particularly in the induction of pathology. Matrix metalloproteinases have been implicated in the metastatic behaviour of schizont-infected cells. The nature of the protective schizont target antigens remains unknown. Attempts to develop a subunit vaccine have focused upon a sporozoite antigen (SPAG-1) and a merozoite antigen (Tams1). Both SPAG-1 and Tams1 have given partial protection using different delivery systems and adjuvants, but further vaccine development will probably require identification of a range of other antigens, especially from the schizont stage. Theileria parva has a tropism for T cells. Vaccination is currently by the 'infection and treatment' method, which involves challenging with a controlled dose of sporozoite stabilate and the simultaneous administration of long-acting tetracyclines. The immunity thus induced is mediated by BoLA-restricted cytotoxic T cells, which recognize polymorphic schizont antigens. These antigens have not been characterized at the molecular level. However, the polymorphic nature of the target antigens underlies the fact that the immunity is very strain specific--a situation that distinguishes T. parva from T. annulata. Interestingly, it is not possible to produce an attenuated vaccine to T. parva, as T. parva requires up to two orders of magnitude more schizonts in order to achieve transfer to the new host. A suggested reason for this is that the macrophage targets of T. annulata are phagocytes and thus the schizont has a natural, efficient route of entry whilst the preferred host of T. parva is the non-phagocytic T cell. Analysis of the cytotoxic T-cell response has revealed evidence of BoLA haplotype dominance plus competition between parasite epitopes. Subunit vaccination using a recombinant sporozoite antigen (p67) has proved very promising, with levels of protection of the order of 70% being achieved. A proportion of the protected calves exhibits complete sterile immunity. Interestingly, the basis for this immunity is not clear, since there is no correlation between the titre of antibodies that inhibit sporozoite penetration of lymphocytes and protection. Similarly, there is no significant T-cell response that distinguishes the protected and susceptible animals. These data are very encouraging, but other components, particularly those derived from the schizont, need to be identified and characterized. The mild Theileria species of Japan and Korea (termed T. sergenti in the literature) cause fever and severe chronic anaemia. The schizont stage of the life cycle is very rare and the host cell type is not known. The pathology is associated with chronic piroplasm infection. Immunity can be induced by immunizing with crude piroplasm extracts. Serological analysis of immune sera reveals that the immunodominant antigen is a polypeptide of 30-33 kDa, which corresponds to the protective T. annulata polypeptide Tams1. (ABSTRACT T

Genetic diversity of major piroplasm surface protein genes and their allelic variants of Theileria parasites in Thai cattle

Twenty-eight field isolated Theileria parasite DNAs obtained from dairy and beef cattle in distinct geographical areas of Thailand were characterized by using polymerase chain reaction (PCR) amplification with six sets of oligonucleotide primers. Three sets of them were modified from two genes of immunodominant major piroplasm surface protein (MPSP) coding for 32 kDa (p32) of T. sergenti and 33/34 kDa (p33/34) of T. buffeli, and MPSP of Theileria spp.(Thai-isolate). The other three sets of primers were basically generated from three alleles of MPSP which were specific for Japanese T. sergenti-Ikeda stock (I-type), Japanese T. sergenti-Chitose stock (C-type) and Australian T. buffeli-Warwick stock (B1-type), respectively. The results indicated that 14 out of 28 isolates were amplified by the Thai-specific primer whereas 6 isolates were amplified by the p32 specific primer and the other 5 isolates were amplified by the p32 and Thai-specific primers. In addition, by using the allele-specific PCR, 14 out of 28 isolates contained C-type MPSP whereas 3 isolates contained B1 type parasites. Interestingly, 20 out of 28 isolates could be amplified by the Thai-specific primer. The majority of Theileria parasites distributed in Thailand contained Thai type parasites, whereas C-type parasites showed the mixed population with B1 and Thai type parasites. No I type parasite was detected.

Detection of porcine epidemic diarrhea virus using polymerase chain reaction and comparison of the nucleocapsid protein genes among strains of the virus

Two pairs of PCR primers were designed to perform nested PCR targetting of a 540 bp fragment of the nucleocapsid (N) protein gene (N gene) of porcine epidemic diarrhea virus (PEDV). The N gene of PEDV was amplified with 4 PEDV strains and 11 small intestines of PEDV-infected piglets collected from 2 farms in Kagoshima prefecture, Japan. Nucleotide sequences of the PCR products from a Korean and two Japanese strains (KKN96-1 and S1) of PEDV isolated in 1993 and 1996, respectively, were almost identical. These results suggest that the PCR is an available tool for detection of PEDV from pigs in the field, and that the two Japanese strains (KKN96-1 and S1) were genetically similar to the Korean strain.

Molecular phylogenetic studies on Theileria parasites based on small subunit ribosomal RNA gene sequences

Classification of Theileria parasites of south-east Asian countries is still ambiguous due to the lack of basic studies, especially their molecular genetic information. In this study, we included 6 known species and 14 unclassified Theileria parasite isolates: Theileria annulata, Theileria parva, Theileria taurotragi, Theileria sergenti, Theileria buffeli, Theileria types Sable, Theileria types A, B, B1, B2, C, D, E, F, G, G1, Theileria type Medan (Indonesia), Theileria type Ipoh (Malaysia) and Theileria type Thong Song (Thailand). Small subunit ribosomal RNA (srRNA) nucleotide sequence data were collected by PCR, cloning and dideoxy sequencing. The srRNA nucleotide sequences were aligned and analyzed by distance methods, maximum parsimony algorithms and maximum likelihood methods to construct phylogenetic trees. Bootstrap analysis was used to test the strength of the different phylogenetic reconstructions. The data indicated that all of the tree-building methods gave very similar results. This study identified two groups of Theileria, the pathogenic and benign groups, which are strongly supported by bootstrap analysis. The analysis also indicated that three subgroups (A, B and C) were generated within the benign Theileria group whereas the classification of Theileria type D and Thong Song is questionable. However, more basic information such as life cycle differences, vectors, modes of transmission, virulent and genetic/sexual compatability is essential for clearer taxonomic definition of the benign Theileria parasites.

Simultaneous detection of bovine Theileria and Babesia species by reverse line blot hybridization

A reverse line blot (RLB) assay was developed for the identification of cattle carrying different species of Theileria and Babesia simultaneously. We included Theileria annulata, T. parva, T. mutans, T. taurotragi, and T. velifera in the assay, as well as parasites belonging to the T. sergenti-T. buffeli-T. orientalis group. The Babesia species included were Babesia bovis, B. bigemina, and B. divergens. The assay employs one set of primers for specific amplification of the rRNA gene V4 hypervariable regions of all Theileria and Babesia species. PCR products obtained from blood samples were hybridized to a membrane onto which nine species-specific oligonucleotides were covalently linked. Cross-reactions were not observed between any of the tested species. No DNA sequences from Bos taurus or other hemoparasites (Trypanosoma species, Cowdria ruminantium, Anaplasma marginale, and Ehrlichia species) were amplified. The sensitivity of the assay was determined at 0.000001% parasitemia, enabling detection of the carrier state of most parasites. Mixed DNAs from five different parasites were correctly identified. Moreover, blood samples from cattle experimentally infected with two different parasites reacted only with the corresponding species-specific oligonucleotides. Finally, RLB was used to screen blood samples collected from carrier cattle in two regions of Spain. T. annulata, T. orientalis, and B. bigemina were identified in these samples. In conclusion, the RLB is a versatile technique for simultaneous detection of all bovine tick-borne protozoan parasites. We recommend its use for integrated epidemiological monitoring of tick-borne disease, since RLB can also be used for screening ticks and can easily be expanded to include additional hemoparasite species.

Inter-species differentiation of benign Theilerias by genomic fingerprinting with arbitrary primers

A method was developed to obtain reproducible DNA fingerprints from five distinct purified benign Theileria genomic DNAs by PCR-based amplification. Randomly amplified polymorphic DNA (RAPD) profiles were obtained from 10 randomly designed 12-mers. However, nine of the 10 primers could generate the difference in RAPD-PCR profiles which allowed discrimination of Theileria species. The method has advantage of being simple, fast and sensitive for diagnosis and characterization of the parasites since it does not require prior DNA sequence information to construct species-specific probes or primers. The results are also beneficial for a proper understanding of the epidemiology and designing rational control programmes for Theileriosis in Asian and South-East Asian countries.

Phylogeny of benign Theileria species from cattle in Thailand, China and the U.S.A. based on the major piroplasm surface protein and small subunit ribosomal RNA genes

The major piroplasm surface protein and small subunit ribosomal RNA genes of benign Theileria species isolated from cattle in China, Thailand and the U.S.A. were amplified by polymerase chain reaction, cloned and sequenced. The major piroplasm surface protein genes of these three isolates were more than 89% identical at amino-acid level. Several deletions in the gene from the Thai isolate led to considerable structural change through frame shifts of the major piroplasm surface protein. Phylogenetic analyses based on both of the major piroplasm surface protein and small subunit ribosomal RNA genes suggest that there may be a second cosmopolitan benign Theileria species infecting cattle in addition to the Theileria sergenti/buffeli/orientalis complex.

Sequence analysis of the major piroplasm surface protein gene of benign bovine Theileria parasites in east Asia

Relatively benign Theileria parasites are widespread among cattle in East Asia. Although the parasites are presumed to be of the Theileria sergenti/Theileria buffeli/Theileria orientalis group, their taxonomic status and epidemiology have not been well defined. In the present study, theilerial DNA samples were collected from various East Asian countries, including Japan, Korea, Taiwan, and China. DNA sequences encoding a major piroplasm surface protein were amplified by polymerase chain reaction, followed by cloning into a plasmid vector. More than 20 DNA clones derived from parasite DNA of a single infected animal were examined for their restriction-fragment-length polymorphism, showing that they were classified into four major types. Sequence analysis revealed six types of DNA sequences encoding major piroplasm surface protein with homologies of between 75 and 91%. Of the six sequences, four were identical to those previously reported, while the other two appeared to be new sequences. Among the DNA clones derived from a single infected animal, two to three distinct sequences were often found. Phylogenetic analysis of the six major piroplasm surface protein sequences indicates that five of the six are closely related to each other, and that all are distantly related to the homologous genes of Theileria annulata and Theileria parva. The results suggest that, in addition to those described as T. sergenti/T. buffeli/T. orientalis, there may be some undefined Theileria species distributed in East Asia, and that many cattle are infected with mixed populations of geographically variable Theileria parasites.

PCR amplification and sequence of the p33 piroplasm surface antigen gene of a Theileria species isolated from cattle in west Java, Indonesia

Oriental theileriosis, a parasitic disease of cattle caused by protozoa of the Theileria orientalis/sergenti/buffeli group, has been reported in Indonesia but its causal agent had not yet been characterized. This study was carried out to isolate and characterize the parasite through comparison of its p33 piroplasm surface antigen gene sequence, with known p32 sequences of T. sergenti and T. buffeli isolates. A Theileria spp. isolate was collected from an Ongole cow in Jonggol, West-Java, and transferred into a splenectomized calf for antigen production. Piroplasms were extracted from erythrocytes by ammonium chloride-lysis, separated from unlysed leukocytes and parasitic DNA was phenol-extracted. Polymerase chain reaction (PCR) was carried out on genomic DNA with a pair of 20 bp primers showing consensus for the p32-35 nucleotide sequence of 7 known T. orientalis/sergenti/buffeli isolates. An 875 bp fragment was amplified, and further sequenced on both strands by the dye-labeled terminators method. It showed an 88% homology with the p33 nucleotide sequence of the Japanese T. sergenti Ikeda stock and a lesser homology with 6 other sequences of Australian T. buffeli or Japanese T. sergenti stocks. It was shown to share the presence of the Pst 1 and the absence of the HindIII restriction sites of the T. sergenti Ikeda stock and of one Australian T. buffeli stock, respectively. In conclusion, the affiliation to and the relative position of this Indonesian isolate within the T. orientalis/sergenti/buffeli group has been elucidated.

Differentiation and quantification of Theileria sergenti piroplasm types using type-specific monoclonal antibodies

Antigenic properties of two representative allelic products of the major piroplasm surface protein (MPSP) of Theileria sergenti were studied. Sera from cattle infected with either of Ikeda and Chitose types of the parasite reacted strongly with homologous but weakly with heterologous recombinant antigens in immunoblotting. Monoclonal antibodies (MoAbs) produced against the both allelic products of MPSP parasites reacted only to the immunizing antigen. These results suggested that crossreactivity between two allelic products is very low inspite of relatively high homology in their amino acid sequences. Double staining of parasitized erythrocyte smear using type-specific MoAbs by an indirect immunofluorescent assay revealed that the set of MoAbs was useful for quantitative and differential detection of each type of parasite in mixed population.

Analysis of immunodominant piroplasm surface protein genes of benign Theileria parasites distributed in China and Korea by allele-specific polymerase chain reaction

Benign Theileria species distributed in China and Korea were characterized by allele-specific polymerase chain reaction (PCR), based on the sequences of major immunodominant piroplasm surface protein genes. In China, all the isolates contained Chitose (C) type parasites. One out of 5 isolates tested was a mixed population of Ikeda (I), C and B-2 types, whereas, all the isolates from Korea consisted of I type parasites. Except for 4 isolates, 29 isolates from Korea consisted of more than two types of parasites. The present data showed that benign Theileria species distributed in these countries were mixed parasite populations.