Survey of benign Theileria parasites of cattle and buffaloes in Thailand using allele-specific polymerase chain reaction of major piroplasm surface protein gene

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.

Theileria infection in bullfighting cattle in Thailand

Background and Aim

An apicomplexan protozoan parasite, namely, Theileria, primarily causes theileriosis in cattle worldwide. The virulence of the disease has been neglected because of it's low pathogenicity. However, the disease can have a substantial effect, depending on the virulence of the species, low host immunity, and coinfection. In Thailand, the molecular detection of Theileria infection in bullfighting cattle and its hematological alterations have not been reported. Thus, this study aimed to identify Theileria species in bullfighting cattle in Thailand.

Materials and Methods

Blood samples were collected from bullfighting cattle presented at the Prince of Songkla University Animal Hospital and were determined on the basis of hematological evaluation and DNA extraction. Molecular detection using the 18s rRNA and merozoite surface antigen genes was conducted for Theileria spp. and Theileria orientalis, respectively. In addition, bidirectional sequencing of the positive samples was performed. Hematological alterations between Theileria infected and uninfected groups were statistically evaluated.

Results

The levels of Theileria spp. and T. orientalis infection in bullfighting cattle were 44.62% (58/130) and 41.54% (54/130), respectively. Theileria orientalis, Theileria sinensis, and Theileria spp. infections were identified in bullfighting cattle samples. Hematological evaluation indicated that the red blood cell (RBC) level was significantly lower in Theileria-infected cattle.

Conclusion

This study was the first to use molecular techniques in the identification of Theileria infection in bullfighting cattle in Thailand, with nearly one-half of the study population infected. Theileria infection in bullfighting cattle altered the RBC level, resulting in anemia. Therefore, tick control measures should be promoted.

Incidence of hemoparasitic infections in cattle from central and northern Thailand

Background

Hemoparasites, such as Babesia spp., Theileria spp. and Anaplasma spp., can negatively affect the health of farm animals resulting in significant losses in production. These losses inherently affect the economics of the livestock industry. Since increases in the severity of vector-borne diseases in the southeast Asian region have been reported, investigations of parasitic epidemiology in Thailand will be necessary to improve the existing parasite control strategies for blood parasitic infections. This study aims to investigate incidences of bovine hemoparasites throughout central and northern Thailand by focusing on areas of high-density cattle populations.

Methods

Blood parasitic infections among cattle were screened and identified by microscopic examination. Anemia status was then determined by evaluation of the packed cell volume (PCV) of each animal. Furthermore, blood parasites were detected and identified by genus and species-specific primers through the polymerase chain reaction method. Amplicons were subjected to DNA sequencing; thereafter, phylogenetic trees were constructed to determine the genetic diversity and relationships of the parasite in each area.

Results

A total of 1,066 blood samples were found to be positive for blood parasitic infections as follows: 13 (1.22%), 389 (36.50%), and 364 (34.15%) for Babesia bovis, Theileria orientalis, and Anaplasma marginale, respectively. Furthermore, multiple hemoparasitic infections in the cattle were detected. The hematocrit results revealed 161 hemoparasitic infected samples from 965 blood samples, all of which exhibiting indications of anemia with no significant differences. Sequence analysis of the identified isolates in this study revealed that B. bovis rap-1, four separate clades of T. orientalis msps, and A. marginale msp4 exhibited considerable sequence similarity to homologous sequences from isolates obtained from other countries. Sequence similarity ranged between 98.57-100%, 83.96-100%, and 97.60-100% for B. bovis rap-1, T. orientalis msps, and A. marginale msp4, respectively.

Conclusion

In this study, the analyzed incidence data of cattle hemoparasitic infection in Thailand has provided valuable and basic information for the adaptation of blood-borne parasitic infections control strategies. Moreover, the data obtained from this study would be useful for future effective parasitic disease prevention and surveillance among cattle.

Low level of genetic diversity and high occurrence of vector-borne protozoa in water buffaloes in Thailand based on 18S ribosomal RNA and mitochondrial cytochrome b genes

Vector-borne pathogens (VBPs) pose a great risk to ruminant production through significant economic losses. Several previous studies in Thailand have mainly been focused on the health of dairy and beef cattle. Water buffaloes are one of the important ruminants in the country, but studies on their infection with VBPs remains limited. We conducted a molecular survey on blood samples from 456 buffaloes obtained from eight provinces across different geographical locations of Thailand. The PCR diagnostics indicated that 116 (25.4%) and 59 (12.9%) of these 456 samples were positive for piroplasm and Plasmodium spp., respectively, and were found in six and all eight regions, respectively, across Thailand. Co-infections of piroplasm and Plasmodium spp. were observed in 24 cases (5.26%). Babesia spp. was not detected in any of the 12 sequenced piroplasm-positive samples in the present study. Genetic comparisons and phylogenetic analyses of within and between parasite populations, based on the 18S ribosomal (r)RNA and cytochrome b (cytb) genes for T. orientalis and P. bubalis, respectively, revealed that T. orientalis shared a high similarity within its population and could be divided into four distinct haplotypes. Haplotypes 1 and 4 were placed in the same clade with the samples previously isolated from cattle in Korea, Japan, Australia, and the USA. Haplotypes 2, and 3 were novel and were placed in a separate clade not shared with the other isolates. We also confirmed our previous investigation that at least three cytb haplotypes of P. bubalis were distributed in the country with a relatively high degree of genetic polymorphisms within its population (based on cytb sequences). Type II P. bubalis was phylogenetically closely related to P. caprae in goats in Zambia and Thailand. This study improves our current understanding on the distribution, intra- and inter-population genetic diversity, and genetic relationship of piroplasms and Plasmodium spp. in water buffaloes.

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.

Molecular detection and genetic diversity of Theileria orientalis in cattle in China

The apicomplexan parasite Theileria orientalis is a tick-borne intracellular protozoan parasite that is widely distributed throughout China. It causes bovine theileriosis in infected cattle, which results in huge economic losses to the cattle industry. In this study, the infection status of T. orientalis was determined in 260 blood samples from cattle from seven provinces across China. Results of a major piroplasm surface protein (MPSP)-PCR assay revealed that an average of 36.5% (95/260) of cattle was positive for T. orientalis infection. Based on the MPSP gene sequences, phylogenetic analysis revealed that these isolates of T. orientalis comprised of eight MPSP types, 1, 2, 3, 4, 5, 7, N1, and N2. This is the first report of new T. orientalis MPSP genotypes N1 and N2 in cattle in China.

The first molecular survey of theileriosis in Malaysian cattle, sheep and goats

This study reports the molecular detection of Theileria spp. from six cattle farms, a sheep farm and a goat farm located at different states in Peninsular Malaysia. Animal blood samples were screened for the presence of Theileria DNA using a conventional polymerase chain reaction (PCR) assay. A total of 155 (69.2%) of 224 cattle investigated were PCR-positive for Theileria DNA. The occurrences of Theileria spp. ranged from 17.5% to 100.0% across six cattle farms. Theileria DNA was detected from 90.0% of 40 sheep but none of 40 goats examined in this study. Sequence analyses of amplified 18S rRNA partial fragments (335-338bp) confirmed the identification of Theileria buffeli, Theileria sergenti, and Theileria sinensis in representative samples of cattle and ticks. T. luwenshuni was identified in the infected sheep. The high occurrences of Theileria spp. in our farm animals highlight the needs for appropriate control and preventive measures for theileriosis.

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.

Molecular epidemiology of bovine Babesia spp. and Theileria orientalis parasites in beef cattle from northern and northeastern Thailand

Beef cattle production represents the largest cattle population in Thailand. Their productivity is constrained by tick-borne diseases such as babesiosis and theileriosis. In this study, we determined the prevalence of Babesia bigemina, Babesia bovis and Theileria orientalis using polymerase chain reaction (PCR). The genetic markers that were used for detection of the above parasites were sequenced to determine identities and similarity for Babesia spp. and genetic diversity of T. orientalis. Furthermore the risk factors for the occurrence of the above protozoan parasites in beef cattle from northern and northeastern parts of Thailand were assessed. A total of 329 blood samples were collected from beef cattle in 6 provinces. The study revealed that T. orientalis was the most prevalent (30.1%) parasite in beef cattle followed by B. bigemina (13.1%) and B. bovis (5.5%). Overall, 78.7% of the cattle screened were infected with at least one of the above parasites. Co-infection with Babesia spp. and T. orientalis was 30.1%. B. bigemina and T. orientalis were the most prevalent (15.1%) co-infection although triple infection with the three parasites was observed in 3.0% of the samples. Sequencing analysis revealed that B. bigemina RAP1 gene and B. bovis SBP2 gene were conserved among the parasites from different cattle samples. Phylogenetic analysis showed that the T. orientalis MPSP gene from parasites isolated from cattle in north and northeast Thailand was classified into types 5 and 7 as reported previously. Lack of tick control program was the universal risk factor of the occurrence of Babesia spp. and T. orientalis infection in beef cattle in northern and northeastern Thailand. We therefore recommend training of farmers on appropriate tick control strategies and further research on potential vectors for T. orientalis and elucidate the effect of co-infection with Babesia spp. on the pathogenicity of T. orientalis infection on beef in northern and northeastern Thailand.

Detection of Theileria orientalis genotypes in Haemaphysalis longicornis ticks from southern Australia

Background

Theileria are blood-borne intracellular protozoal parasites belonging to the phylum Apicomplexa. Previously considered a benign parasite in Australia, outbreaks of clinical disease resulting from Theileria orientalis genotypes have been reported in Australia since 2006. Since this time, outbreaks have become widespread in south-eastern Australia, resulting in significant adverse impacts on local dairy and beef industries. This paper provides the first investigation into the possible biological and mechanical vectors involved in the rapid spread of the parasite.

Methods

To identify possible vectors for disease, ticks, biting flies and mosquitoes were collected within active outbreak regions of Gippsland, Victoria. Ticks were collected from cattle and wildlife, and mosquitoes and biting flies were collected in traps in close proximity to outbreak herds. Ticks were identified via DNA barcoding of the mitochondrial cytochrome oxidase I gene. Barcoded ticks were pooled according to species or phylogenetic group and tested for the presence of T. orientalis and the genotypes Ikeda, Chitose and Buffeli using real-time PCR.

Results

DNA barcoding and phylogenetic analysis identified ticks from the following species: Haemaphysalis longicornis, Ixodes holocyclus, Ixodes cornuatus, Ixodes hirsti, and Bothriocroton concolor. Additional Haemaphysalis, Ixodes and Bothriocroton spp. were also identified. Of the ticks investigated, only H. longicornis ticks from cattle carried theilerial DNA, with the genotypes Ikeda, Chitose and Buffeli represented. Mosquitoes collected in close proximity to outbreak herds included; Aedes camptorhynchus, Aedes notoscriptus, Coquillettidia linealis, Culex australicus, and Culex molestus. Low levels of T. orientalis Buffeli genotype were detected in some mosquitoes. The haematophagous flies tested negative.

Conclusions

This is the first demonstration of a potential vector for T. orientalis in the current Australasian disease outbreak.

Evolution and genetic diversity of Theileria

Theileria parasites infect a wide range of domestic and wild ruminants worldwide, causing diseases with varying degrees of severity. A broad classification, based on the parasite's ability to transform the leukocytes of host animals, divides Theileria into two groups, consisting of transforming and non-transforming species. The evolution of transforming Theileria has been accompanied by drastic changes in its genetic makeup, such as acquisition or expansion of gene families, which are thought to play critical roles in the transformation of host cells. Genetic variation among Theileria parasites is sometimes linked with host specificity and virulence in the parasites. Immunity against Theileria parasites primarily involves cell-mediated immune responses in the host. Immunodominance and major histocompatibility complex class I phenotype-specificity result in a host immunity that is tightly focused and strain-specific. Immune escape in Theileria is facilitated by genetic diversity in its antigenic determinants, which potentially results in a loss of T cell receptor recognition in its host. In the recent past, several reviews have focused on genetic diversity in the transforming species, Theileriaparva and Theileriaannulata. In contrast, genetic diversity in Theileriaorientalis, a benign non-transforming parasite, which occasionally causes disease outbreaks in cattle, has not been extensively examined. In this review, therefore, we provide an outline of the evolution of Theileria, which includes T. orientalis, and discuss the possible mechanisms generating genetic diversity among parasite populations. Additionally, we discuss the potential implications of a genetically diverse parasite population in the context of Theileria vaccine development.

Phylogeny of Theileria buffeli genotypes identified in the South African buffalo (Syncerus caffer) population

Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and buffalo in various parts of the world. In a previous study, we identified T. buffeli in blood samples originating from the African buffalo (Syncerus caffer) in the Hluhluwe-iMfolozi Game Park (HIP) and the Addo Elephant Game Park (AEGP) in South Africa. The aim of this study was to characterise the 18S rRNA gene and complete internal transcribed spacer (ITS1-5.8S-ITS2) region of T. buffeli samples, and to establish the phylogenetic position of this species based on these loci. The 18S rRNA gene and the complete ITS region were amplified from DNA extracted from blood samples originating from buffalo in HIP and AEGP. The PCR products were cloned and the resulting recombinants sequenced. We identified novel T. buffeli-like 18S rRNA and ITS genotypes from buffalo in the AEGP, and novel Theileria sinensis-like 18S rRNA genotypes from buffalo in the HIP. Phylogenetic analyses indicated that the T. buffeli-like sequences were similar to T. buffeli sequences from cattle and buffalo in China and India, and the T. sinensis-like sequences were similar to T. sinensis 18S rRNA sequences of cattle and yak in China. There was extensive sequence variation between the novel T. buffeli genotypes of the African buffalo and previously described T. buffeli and T. sinensis genotypes. The presence of organisms with T. buffeli-like and T. sinensis-like genotypes in the African buffalo could be of significant importance, particularly to the cattle industry in South Africa as these animals might act as sources of infections to naïve cattle. This is the first report on the characterisation of the full-length 18S rRNA gene and ITS region of T. buffeli and T. sinensis genotypes in South Africa. Our study provides invaluable information towards the classification of this complex group of benign and mildly pathogenic species.

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.

Epidemiological survey following oriental theileriosis outbreaks in Victoria, Australia, on selected cattle farms

This study investigated Theileria orientalis following outbreaks of oriental theileriosis in cattle in the state of Victoria, Australia, from September 2010 to January 2012, using traditional and molecular methods of diagnosis. A questionnaire was used to collect epidemiological information from cattle farms. Blood samples (n=301), collected from individual symptomatic and asymptomatic cattle from 19 cattle farms, were examined for the presence of Theileria on stained blood smears and tested using a PCR-based approach, employing a region within the major piroplasm surface protein (MPSP) gene as a marker. The microscopic examination of stained blood smears detected stages consistent with Theileria piroplasms in 28.1% (79/281) of the samples. PCR products were amplified from 70.8% (213/301) of the samples. Mutation scanning analysis of all amplicons displayed seven distinct profiles. Following the direct sequencing of representative amplicons, the genotypes ikeda, chitose, buffeli and type 5 were detected in 91.1%, 32.9%, 2.4% and 1.4% of 213 blood samples, respectively. The distribution of these four genotypes varied among the 19 farms; genotype ikeda was detected on all farms, whereas genotypes chitose, buffeli and type 5 were detected on 14, 3 and 2 farms, respectively. Mix infections with genotypes ikeda and chitose were common (21.6%). Survey results revealed that oriental theileriosis affected mainly beef cows of more than two years of age, prior to calving, and disease was associated with abortion and cow deaths. Future investigations should focus on developing improved tools for investigating and managing oriental theileriosis.

Molecular detection of Theileria species in sheep from northern China

Ovine theileriosis is a tick-borne disease that restricts the development of small ruminant husbandry in northern China. In this study, we report on a molecular epidemiological survey of ovine Theileria spp. in 198 blood samples taken from sheep in northern China. The DNA samples were screened by a nested polymerase chain reaction (PCR) targeting the 18S rRNA gene of ovine Theileria spp. The prevalence of ovine Theileria spp. in Yanji, Nongan, Longjing, Toudao and Jinchang was 80%, 40%, 37%, 24% and 32%, respectively. The sequencing analyses approved the present of the T. orientalis and/or T. luwenshuni in these regions. Taken together, we have demonstrated a high incidence of Theileria spp. in northern China that calls for the need to design effective control programs for ovine theileriosis.

Mutation scanning-based analysis of Theileria orientalis populations in cattle following an outbreak

Bovine theileriosis is a tick-borne disease caused by one or more hemoprotozoan parasites of the genus Theileria. In the past, Theileria infection in cattle in Australia was largely asymptomatic and recognized to be associated with Theileria buffeli. However, outbreaks of theileriosis have occurred in beef and dairy cattle in subtropical climatic regions (New South Wales) of Australia. There is also one published report of a recent theileriosis outbreak in a beef farm near Seymour in the southeastern state of Victoria. In order to gain an improved insight into the genetic composition of Theileria populations following this outbreak, we undertook herein an integrated PCR-coupled mutation scanning-sequencing-phylogenetic analysis of sequence variation in part of the major piroplasm surface protein (MPSP) gene within and among samples from cattle involved in the outbreak. Theileria DNA was detected in 89.4% of 94 cattle in the Seymour farm; the genetic analysis showed that the ikeda and chitose genotypes representing the Theileria orientalis complex were detected in 75 and 4.8% of 84 infected cattle, respectively, and that mixed populations of these two genotypes were found in 20.2% of infected cattle. Given unpublished reports of a significant increase in the number of outbreaks in Victoria, future investigations should focus sharply on elucidating the epidemiology of Theileria to subvert the economic impact on the cattle industry in this state. Although used here to explore genetic variation within the T. orientalis complex in Australia, a mutation scanning-based approach has broad applicability to other species of Theileria in other countries.

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.

Molecular prevalence of different genotypes of Theileria orientalis detected from cattle and water buffaloes in Thailand

Here we report on an epidemiological study regarding the molecular prevalence of different genotypes of Theileria orientalis present among domestic cattle and water buffalo populations bred in Thailand. A phylogenetic analysis based on the parasitic gene encoding a major piroplasm surface protein revealed the presence of 5 genotypes (Types 1, 3, 5, 7, and N-3) in cattle and 7 genotypes (Types 1, 3, 4, 5, 7, N-2, and N-3) in water buffaloes. Types 4, 7, and N-3 of T. orientalis were reported for the first time in water buffaloes. The previously reported C and Thai types from Thailand clustered as types 7 and 6, respectively, in the present analysis. Great similarities were observed among nucleotide sequences of isolates of the same genotype from cattle and water buffaloes, and, therefore, water buffaloes were considered to serve as a reservoir for these genotypes of T. orientalis in Thailand. In conclusion, T. orientalis parasites circulating in Thailand are more diverse in their genetic characters than previously anticipated.

Emergence of new types of Theileria orientalis in Australian cattle and possible cause of theileriosis outbreaks

Theileria parasites cause a benign infection of cattle in parts of Australia where they are endemic, but have, in recent years, been suspected of being responsible for a number of outbreaks of disease in cattle near the coast of New South Wales. The objective of this study was to identify and characterize the species of Theileria in cattle on six farms in New South Wales where disease outbreaks have occurred, and compare with Theileria from three disease-free farms in Queensland that is endemic for Theileria. Special reference was made to sub-typing of T. orientalis by type-specific PCR and sequencing of the small subunit (SSU) rRNA gene, and sequence analysis of the gene encoding a polymorphic merozoite/piroplasm surface protein (MPSP) that may be under immune selection. Nucleotide sequencing of SSU rRNA and MPSP genes revealed the presence of four Theileria genotypes: T. orientalis (buffeli), T. orientalis (ikeda), T. orientalis (chitose) and T. orientalis type 4 (MPSP) or type C (SSU rRNA). The majority of animals showed mixed infections while a few showed single infection. When MPSP nucleotide sequences were translated into amino acids, base transition did not change amino acid composition of the protein product, suggesting possible silent polymorphism. The occurrence of ikeda and type 4 (type C) previously not reported to occur and silent mutation is thought to have enhanced parasite evasion of the host immune response causing the outbreak.

Molecular epidemiological survey of Theileria orientalis in Thua Thien Hue Province, Vietnam

Theileria orientalis is a benign bovine protozoan parasite that occasionally causes serious economic loss in the livestock industry. We report the findings of a molecular epidemiological survey of T. orientalis in 94 Vietnamese yellow cattle, 43 water buffaloes, 21 sheep, 21 goats and 85 blood-sucking ticks of cattle in the Thua Thien Hue province of Vietnam. The major piroplasm surface protein (MPSP) gene of T. orientalis was detected using polymerase chain reaction from 13 cattle (13.8%), 11 water buffaloes (25.6%), 1 sheep (4.8%) and 9 ticks (10.6%). Phylogenetic analysis using MPSP gene sequences showed the presence of seven genotypes, four previously categorized genotypes (Types 1, 3, 5 and 7) and three new genotypes (Types N-1, N-2 and N-3).

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.

Antigenic diversity of Theileria major piroplasm surface protein gene in Jeju black cattle

Piroplasms are tick-transmitted, intracellular, hemoprotozoan parasites that cause anorexia, fever, anemia, and icterus. Theileriosis is caused by Theileria sergenti and causes major economic losses in grazing cattle in Japan and Korea. In May 2003, we examined the antigenic diversity of the major piroplasm surface protein (MPSP) gene in 35 healthy Jeju black cattle that were born and raised at the National Institute of Subtropical Agriculture. On microscopic examination of Giemsa-stained blood smears, 9 of 35 cattle had intra-erythrocytic piroplasms. Hematological data were within normal range for all 35 cattle. Amplification of DNA from all blood samples using universal MPSP gene primers showed mixed infections with C, I, and B type Theileria spp. Type C was identified in 20 of 35 blood samples, and type B was identified in 17 samples. Allelic variation was seen in type B.

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.