Wide bovine tick-borne pathogen spectrum: Predominancy of Theileria annulata and the first molecular detection of Ehrlichia minasensis in Turkey

Vector-borne diseases indulge in severe economic losses in the livestock industry by adversely affecting cattle breeding in tropical and subtropical zone countries, including Turkey, encompassing a wide land area representing diverse climatic conditions. This study aimed to investigate significant bovine tick-borne piroplasm, rickettsia, and some other bacterial agents by genus- or species-specific PCR and nested PCR techniques in Turkey. A total of 210 cattle blood samples were collected from sixteen provinces in different geographical regions of Turkey. PCR analyses were performed targeting the detection of Babesia/Theileria/Hepatozoon sp. 18S rRNA, Babesia/Theileria sp. 18S rRNA (V4), B. bigemina RAP-1a, B. bovis SBP-4, B. ovata AMA-1, B. naoaki AMA-1, T. annulata Tams-1, T. orientalis MPSP, T. mutans 18S rRNA, Anaplasma/Ehrlichia sp. 16S rRNA, A. marginale MSP4, A. bovis 16S rRNA, A. phagocytophilum 16S rRNA, A. capra 16S rRNA, E. ruminantium pSC20, Mycoplasma sp. 16S rRNA, and Coxiella burnetii 16S rRNA genes. Overall, 133 (63.3%) cattle were found to be infected with at least one of the following protozoan or bacterial pathogens; B. bovis, B. bigemina, B. occultans, T. annulata, T. orientalis, A. marginale, A. phagocytophilum, and Mycoplasma sp. The total prevalence of pathogens was determined as follows; 0.5% B. bovis, 0.5% B. bigemina, 1.4% B. occultans, 41.0% T. annulata, 1.4% T. orientalis, 10.5% A. marginale, 13.8% A. phagocytophilum, 0.5% A. bovis, 2.9% Uncultured Anaplasma sp., 0.5% E. minasensis, 0.5% Uncultured Ehrlichia sp., and 23.3% Mycoplasma sp. Moreover, large part of the total infection (n:133) was composed of single infections (63.9%); however, double (24.8%), triple (7.5%), quadruple (2.3%), and quintuple (1.5%) co-infections were also encountered. In addition to some bovine pathogens such as B. occultans, T. orientalis, A. bovis, M. wenyonii, and Candidatus Mycoplasma haemobos, which were rarely reported in Turkey, sequencing and phylogenetic analysis revealed the first detection of Uncultured Ehrlichia sp. (0.5%), and E. minasensis (0.5%) with 100% nucleotide sequence identities. The study also indicates that the spectrum of pathogens harbored by Turkish cattle is quite wide, and these pathogens cause multiple co-infections with various combinations, and T. annulata stands out as the primary bovine pathogen among them.

Equine Piroplasmosis in Asymptomatic Horses of Western Iran: Comparison of Microscopic Examination and Multiplex PCR

PURPOSE

Piroplasmosis is responsible for anemia, fever, loss of physical activity and even death in equines. In epidemiological studies, accurate diagnostic tests are essential for detecting asymptomatic carriers. This study aimed to investigate the prevalence of infection in asymptomatic horses from Lorestan province, western Iran by developing a multiplex PCR.

METHODS AND RESULTS

Blood samples were examined by microscopy and multiplex PCR targeting the SSU rRNA gene of Theileria equi and Babesia caballi. Out of the total of 165 horses, 19 (11.51%) and 31 (18.78%) cases were positive for piroplasms by microscopy and PCR, respectively. The detection rates of both genera were significantly higher in multiplex PCR compared to microscopy (p < 0.0001). Compared with multiplex PCR, the sensitivities of microscopy for the detection of Babesia were only 28.5%. The prevalence of T. equi infection was significantly higher in summer (p = 0.035). The prevalence of B. caballi was significantly higher in males (p = 0.038).

CONCLUSION

Findings indicate that the multiplex PCR described here is a sensitive technique for the detection of piroplasm DNA in carriers. Furthermore, asymptomatic carriers must be considered as an important source of infection for equids living in this region.

Characterisation of field tropical Theileriosis and associated risk factors in two bioclimatic areas of Algeria

Tropical theileriosis (TT) is a tick-borne disease caused by Theileria annulata and commonly infects cattle in tropical and subtropical regions, including Algeria. It is a significant obstacle to cattle breeding programs established to improve production in Algeria. The present investigation aimed to estimate the current molecular prevalence, risk factors, and genetic characterisation of T. annulata in two bioclimatic areas of Algeria. In a cross-sectional study, 679 blood samples (629 from healthy cattle selected on farms and 50 from diseased cattle identified by veterinarians) were collected from the humid (n = 307+50) and semi-arid (n = 322) areas and screened by blood smear examination followed by polymerase chain reaction targeting cytochrome oxidase subunit 3 (cox III) mitochondrial and the 18S ribosomal RNA (18S rRNA) genes for Theileria spp. Seventy-six positive samples (56 clinically healthy and 20 with clinical signs) for Theileria spp. were confirmed to be T. annulata by the merozoïtes surface antigen-1 (Tams1) gene showing a rate of 8.9 % in clinically healthy and 40.0 % in suspected cattle. Among the 307 bloods samples collected from healthy cattle in the humid area, 25 cattle (8.1 %) were positive for T. annulata. Of the 322 healthy cattle from the semi-arid site, 31 (9.6 %) were carriers of T. annulata DNA. In subclinical population, demographic and environmental parameters analysis indicated that T. annulata infection was higher in adult crossbred cattle raised in the intensive and semi-intensive system (P<0.001). The multiple logistic regression analysis showed that age, breed, farming system, and bioclimatic area are potential risk factors for T. annulata infection in cattle (P<0.05). Multiple alignments of cox III sequences of T. annulata showed high heterogeneity with 25 polymorphic sites (nucleotide diversity π = 0.02402), resulting in two haplotypes with a low genetic diversity index (Hd) of 0.533. The 18S rRNA sequence alignment revealed only one T. annulata genotype with 100 % identity to the strains isolated from cattle and ticks in Mediterranean and Asian countries. Our preliminary results will serve as a basis for further studies on the genetic diversity and molecular epidemiology of T. annulata.

THEILERIA EQUI INFECTION IN WORKING HORSES OF PAKISTAN: EPIDEMIOLOGY, MOLECULAR CHARACTERIZATION, AND HEMATOBIOCHEMICAL ANALYSIS

Theileria equi is 1 of the emerging and prevailing tick-borne hemoprotozoans adversely affecting the equids worldwide, including Pakistan. The current study aimed to investigate the prevalence and molecular characterization of T. equi in working horses (n = 194), the comparative efficacy of different diagnostic tests, associated risk factors, and hematobiochemical analysis. The blood samples of horses were subjected to microscopic examination, cELISA, and polymerase chain reaction (PCR) and the results revealed a prevalence of 9.79, 21.13, and 13.40%, respectively, for T. equi in working horses. The comparison of microscopy and cELISA results with PCR showed that cELISA had higher sensitivity (84.62%), but lower specificity (88.69%) and accuracy (88.14%) in comparison to microscopy (57.69, 97.62, and 92.27%). Molecular characterization of T. equi by phylogenetic analysis revealed a 61% resemblance of study isolates with each other OL662926, OL662925, and 82% similarity with isolate OL662924 while also showing homology with T. equi isolates of South Africa, South Korea, India, Pakistan, and Brazil. The risk factor analysis revealed a significant association (P < 0.05) of tick control status, previous tick history, tick infestation, house hygiene, deworming/vaccination, and the presence of other livestock species with T. equi infection in horses. The hematobiochemical profile revealed a significant (P < 0.05) decrease in red blood cells (RBCs), hemoglobin (Hb), packed cell volume (PCV), white blood cells (WBCs), platelet (PLT), phosphorus, and an increase in lymphocytes, granulocytes, aspartate aminotransferase (AST), glucose, bilirubin, blood urea nitrogen (BUN), and creatinine in T. equi-infected horses. The current study is the first comprehensive report for comparative evaluation of microscopy, cELISA, and PCR, assessment of epidemiological risk factors as well as hematobiochemical variations due to T. equi infection in Pakistan.

Comparative evaluation of diagnostic methods for detection of Theileria spp. in cows

Theileriosis is a hemoprotozoan illness of cattle in tropical regions that poses a severe economic loss to dairy farmers in the form of production loss and mortality. We designed and optimized a multiplex real-time PCR by using Taq-Man® probe for detection and quantification of Theileria orientalis and Theileria annulata simultaneously by targeting 18 s rRna and MPSP (surface merozoite protein) genes, respectively. Fifty-five EDTA blood samples from clinically Theileria-suspected cows of three Theileria-endemic districts of Odisha were processed using acridine dye based fluorescent microscopy, Giemsa staining, and PCR. PCR revealed T. annulata and T. orientalis in 11/42 (26.11%) and 24/42 (57.14%) cases, respectively. Mixed infection due to both the Theileria spp. was recorded in 7/42 (16.66%). On comparison with gold standard test (PCR), the accuracy, sensitivity, and specificity were 92.72, 95.12, and 85.71% for Giemsa staining and 96.36, 97.56, and 92.85% for acridine orange dye. Multiplex real time PCR using Taq-Man probe detected two species of T. annulata and T. orientalis simultaneously. Acridine dye based fluorescent microscopy is comparatively easy and rapid method in detection of Thelieria spp.

Development and evaluation of specific polymerase chain reaction assays for detecting Theileria equi genotypes

BACKGROUND

Theileria equi causes equine piroplasmosis, an economically significant disease that affects horses and other equids worldwide. Based on 18S ribosomal RNA (18S rRNA sequences), T. equi can be classified into five genotypes: A, B, C, D, and E. These genotypes have implications for disease management and control. However, no conventional polymerase chain reaction (PCR) assays are available to differentiate the genotypes of T. equi. To overcome this limitation, we developed and evaluated PCR assays specific for the detection of each T. equi genotype.

METHODS

A pair of forward and reverse primers, specifically targeting the 18S rRNA sequence of each genotype, was designed. The genotype-specific PCR assays were evaluated for their specificity using plasmids containing inserts of the 18S rRNA sequence of each genotype. Subsequently, the assays were tested on 270 T. equi-positive equine blood DNA samples (92 from donkeys in Sri Lanka and 178 from horses in Paraguay). 18S rRNA sequences derived from the PCR amplicons were analyzed phylogenetically.

RESULTS

Each genotype-specific PCR assay accurately targeted the intended genotype, and did not produce any amplicons when 18S rRNA from other T. equi genotypes or genomic DNA of Babesia caballi or uninfected horse blood was used as the template. Previous studies employing PCR sequencing methods identified T. equi genotypes C and D in the Sri Lankan samples, and genotypes A and C in the Paraguayan samples. In contrast, our PCR assay demonstrated exceptional sensitivity by detecting four genotypes (A, C, D, and E) in the Sri Lankan samples and all five genotypes in the Paraguayan samples. All the Sri Lankan samples and 93.3% of the Paraguayan samples tested positive for at least one genotype, further emphasizing the sensitivity of our assays. The PCR assays also had the ability to detect co-infections, where multiple genotypes in various combinations were detected in 90.2% and 22.5% of the Sri Lankan and Paraguayan samples, respectively. Furthermore, the sequences obtained from PCR amplicons clustered in the respective phylogenetic clades for each genotype, validating the specificity of our genotype-specific PCR assays.

CONCLUSIONS

The genotype-specific PCR assays developed in the present study are reliable tools for the differential detection of T. equi genotypes.

Differential diagnosis of theileriosis through blood smear examination and polymerase chain reaction in small ruminants from Pakistan

Background

Ovine and caprine theileriosis is a tick-borne hemoprotozoan disease, caused by Theileria spp., responsible for heavy economic losses in terms of high mortality and morbidity rates. Diagnosis of ovine theileriosis is primarily based on clinical symptoms, microscopic screening of stained blood smears, and lymph node biopsy smears, but the limitations of these detection methods against Theileria spp. infection limits their specificity.

Aim

To overcome these limitations, the current study reports the differential diagnosis of theileriosis through a blood smear examination and polymerase chain reaction (PCR) in small ruminants from Pakistan.

Methods

The study was conducted on 1,200 apparently healthy small ruminants (737 sheep and 463 goats). First, blood smears were screened for the presence of Theileria piroplasms in red blood cells. Second, PCR amplification based on 18S rRNA gene was performed by using primers specific to Theileria spp.

Results

Out of the 1,200 samples of examined blood smears, 100 animals (8.33%) were found positive for Theileria species, which showed intra-erythrocytic bodies in the form of dot and comma shapes. Amplification of the isolated DNA from randomly collected blood samples of 737 sheep and 463 goats showed that an amplicon size of 1,098 bp was positive for Theileria spp. In total, 315 out of the 1,200 small ruminants examined in this study were found positive for Theileria spp. DNA through PCR amplification. Notably, out of the 885 blood samples negative by PCR amplification, only 15 blood samples were found positive by the blood smear test. Conversely, 230 blood samples that tested negative in the smear technique produced a specific band through PCR amplification. Overall, the sensitivity and specificity rates were 26.98% and 98.31% for the blood smear method and 73.01% and 100% for the PCR assay, respectively.

Conclusion

Our finding suggests that PCR is the gold standard method compared to the conventional method of smear examination for the diagnosis of ovine and caprine theileriosis in Pakistan.

18S rRNA Gene-Based Piroplasmid PCR: An Assay for Rapid and Precise Molecular Screening of Theileria and Babesia Species in Animals

PURPOSE

The parasites of genera such as Babesia and Theileria are called piroplasmids due to the pear-shaped morphology of the multiplying parasite stages in the blood of the vertebrate host. Because of the enormous number of parasite species and the challenges of multiplex PCR, initial screening of samples using piroplasmid-specific PCR may be a more cost-effective and efficient technique to identify parasite species, especially during epidemiological studies. Accordingly, 18S rRNA PCR was standardized and optimized on common piroplasmids of different animals like cattle, buffaloes, sheep, goats, dogs, horses, and leopards.

METHODS

Bloods samples from 1250 animals were collected from different animals in Junagadh district of Gujarat, India. 18S rRNA PCR was standardized and optimized as a primary method for molecular screening of piroplasms in domestic and wild animals. The method was checked for its analytical sensitivity and specificity. Parasite species-specific PCR and sequencing was used to validate the test. Moreover, in-silico restriction enzyme (RE) analysis was also done to assess its applicability in PCR-RFLP.

RESULTS

Piroplasm infections were recorded in 63.3% of animals in Junagadh. The 18S rRNA PCR detected the piroplasmid DNA in as low as 39 picograms (pg) of whole blood genomic DNA isolated from microscopically Theileria positive blood samples and no reactivity was recorded from common but unrelated haemoparasites viz., Trypanosoma evansi, Hepatozoon spp., Anaplasma spp., and Ehrlichia canis was observed. The 18S rRNA PCR assay findings were confirmed by species-specific PCR and sequencing. Analysis of different sequences generated using 18S rRNA PCR revealed that the amplicon size of Babesia spp. is nearly 400 bp (393-408 bp) whereas Theileria spp. were more than 400 bp (418-424 bp). The percentage of sequence divergence among Babesia and Theileria spp. was 7.3-12.2% and 0.7-12.2%, respectively. In-silico restriction enzyme (RE) analysis reveals the presence of at least one site for a commercially available RE in 18S rRNA fragments of every parasite, which can differentiate it from its congeners.

CONCLUSIONS

The presented universal oligonucleotide-based PCR assay provides a highly sensitive, specific, cost-effective, and rapid diagnostic tool for the initial screening of piroplasmids infecting domestic and wild animals and is potentially helpful for large-scale epidemiological studies.

Serological and molecular detection of Babesia caballi and Theileria equi in Mexico: A prospective study

Equine piroplasmosis is a disease of horses, mules and donkeys, caused by the hemoprotozoans Babesia caballi and Theileria equi and transmitted by ticks of tropical and subtropical regions. Because the clinical signs are not specific, the diagnosis of equine piroplasmosis is difficult. In Mexico, where the environmental factors are conducive to the persistence of these pathogens, there is a lack of molecular studies to evaluate the occurrence of both parasites in horses. In the present study, matching serum and whole blood samples were obtained from 269 horses residing in 24 locations with tropical or subtropical climate and the presence of ticks. Testing of serum samples by ELISA demonstrated 55.7% seroprevalence of B. caballi and 68.4% prevalence of antibodies to T. equi. Blood samples analyzed with nPCR test were 7.8% positive to B. caballi and 78.8% positive to T. equi, while a duplex qPCR showed 15.24% positive samples to B. caballi and 59.11% to T. equi. From these results, 27 samples were sequenced for T. equi and 13 for B. caballi, confirming the presence of both horse parasites that cause equine piroplasmosis and suggesting that they are widespread in Mexico. This is the first study confirming the presence of B. caballi and T. equi in Mexico using both serological and molecular diagnostic methods. This study shows a high incidence of exposure to the etiological agents of equine piroplasmosis in horses in the studied areas.

Insights into equine piroplasmosis in Venezuelan sport horses: Molecular diagnosis, clinical, and cardiovascular findings

Equine piroplasmosis (EP) is a tick-borne infectious disease highly prevalent in tropical and subtropical regions, such as Venezuela. EP affects wild and domestic equids leading to several clinical presentations, from asymptomatic to severely affected animals. In this study, thirty-three (33) sport horses under regular training activities and from endemic regions of north-central Venezuela were submitted to an observational survey, case-control, to describe the presence of clinical signs and natural EP infections. A conventional PCR assay targeting the SSU rRNA gene revealed EP etiologic agents in 13 out of 33 sampled horses (~ 39.4% infections). Nine (9) of these EP-positive samples were confirmed as infected with Babesia caballi (6/9 = 66.7%) or Theileria equi (3/9 = 33.3%) by DNA sequencing and BLASTN analyses. A phylogeny of SSU rRNA gene sequences revealed that these new B. caballi and T. equi sequences clustered within the worldwide distributed phylogenetic genotype A, respectively. No acute EP cases were observed in this study; however, six (6) PCR-positive animals displayed mild clinical signs compatible with EP, including a mild leukocytosis (P < 0.05). The heart rate variability frequency domain analysis in four (4) of these EP-positive infected animals revealed a significant (P < 0.05) higher low-frequency/high-frequency ratio suggesting a sympathovagal imbalance in these chronically infected animals. Other clinical and cardiovascular parameters were similar between the different groups. Sport horses are routinely submitted to intense training programs and sport-related activities that could lead to loss of the host-parasite equilibrium that characterizes enzootic regions, increasing the likelihood of infection reactivation and the risk of transmission. Heart rate variability analysis contributes to evaluate the sympathovagal balance and detecting homeostasis disturbances in sport horses. Molecular diagnostic tests for EP based on the detection of parasite DNA in equine blood samples should be included in the health programs of sport horses in endemic areas.

Theileria infection with severe anemia and unhealed fracture in a sika deer Cervus nippon aplodontus (Cervidae: Cetartiodactyla)

An adult female sika deer (Cervus nippon aplodontus) inhabiting Nara Park, Nara, Japan, had broken bone injuries from a car accident. During its treatment, we found that the sika deer had severe anemia and the fracture remained unhealed throughout. Peripheral blood smear revealed piroplasms in the erythrocytes, which were identified as merozoites of undescribed Theileria species, widely found in sika deer in Japan. This is the report of a clinical case of Theileria infection, accompanied by severe anemia in a sika deer.

End Point Multiplex PCR for Diagnosis of Haemoprotozoan Diseases in Cattle

BACKGROUND

Theileriosis, trypanosomosis and babesiosis are the three major haemoprotozoan diseases causing huge economic losses worldwide. Difficulty in diagnosis of these diseases lies with the detection of carrier state with low parasitemia and concurrent infection.

PURPOSE

The present study was conducted to standardize and evaluate multiplex PCR assay for specific, fast and simultaneous detection of Theileria annulata, Trypanosoma evansi and Babesia bovis in bovines.

METHODS

Positive parasitic DNA was obtained from microscopically positive samples. Simplex PCR assay was developed targeting repetitive nucleotide sequences for Trypanosoma evansi and gene coding enzyme carbamoyl phosphate synthetase II for Babesia bovis. For theileriosis conditions already standardized targeting cytochrome b gene was used. Gradient PCR assay was used to determine common amplification conditions and develop multiplex PCR assay. Limit of detection was determined using tenfold serial dilution of parasitic DNA. Blood samples collected from 117 bovines suspected for haemoparasite infection was tested by simplex and multiplex PCR assay.

RESULTS

Simplex PCR assay was able to detect Theileria annulata, Trypanosoma evansi and Babesia bovis at dilution 10^-9, 10^-8 and 10^-8 which corresponds to copy number 1, 10 and 10, respectively, whereas of multiplex PCR assay was found to be 10^-7 dilution corresponding to 100 copy number. PCR products bands obtained in multiplex PCR assay at 257, 312 and 446 bp were easily distinguishable. Results of simplex PCR assay for detection of individual parasites revealed 48 (41.02%), 27 (23.07%) and 5 (4.27%) samples positive for T. annulata, T. evansi and B. bovis, respectively. Sixty-three (53.8%) samples were found positive by multiplex PCR assay with 15 samples (23.8%) showing mixed infection.

CONCLUSION

Multiplex PCR assay was found to be highly specific and can be used for easy, early, sensitive, specific and simultaneous diagnosis of haemoprotozoan diseases in epidemiological survey as a robust tool.

Atypical theileriosis with cutaneous involvement in a cow in India: a case report

Bovine tropical theileriosis caused by Theileria annulata is an overwhelming haemoprotozoan tick-borne disease in taurine and cross-bred cattle in Punjab, India. However, there seems to be no report from India of cutaneous nodules associated with the disease. This report describes a five-year-old cross-bred cow presented to a university clinic with a history of fever, inappetence and malaise for the past six to seven days. Clinical examination revealed normal vital parameters, pale mucous membranes, mild enlargement of the prescapular lymph nodes and multiple subcutaneous nodular masses (2-4 cm) on the neck and abdomen. Haematology revealed mild anaemia and leucopenia with 48% neutrophils, 48% lymphocytes and 4% eosinophils. Romanowsky-stained smears of fineneedle aspiration biopsy samples from swollen lymph nodes and subcutaneous masses showed an increased number of lymphoid cells, suggesting cutaneous lymphomatosis. However, a critical examination of the smears from subcutaneous nodules showed a large number of Koch's blue bodies in macrophages and lymphoblasts, and several piroplasms were also noticed within the red blood cells in lymph node smears. A peripheral blood smear revealed mild to moderate parasitaemia. Extracted DNA from the parasitologically positive blood sample was subjected to nested polymerase chain reaction (nPCR) using T. annulata speciesspecific primers encoding the 30-kiloDalton major sporozoite surface antigen. The desired 572-base pair amplified product of the nPCR was comparable to the positive control. This seems to be a rare case of T. annulata in an adult cross-bred cow, showing cutaneous nodular involvement.

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.

Rapid detection and differentiation of Theileria annulata, T. orientalis and T. sinensis using high-resolution melting analysis

Bovine theileriosis, caused by protozoan parasites of the genus Theileria, presents with various clinical symptoms. In cattle, clinical presentations and outcomes of bovine theileriosis are closely correlated with the causative Theileria spp. Thus, accurate detection and discrimination of Theileria spp. are essential for epidemiological studies and for provision of clinical management strategies. High-resolution melting (HRM) analyses of two amplicons targeting the 18S rRNA indicated that T. annulata, T. orientalis, and T. sinensis isolated from China can be accurately detected and discriminated with the lowest detection limit of 1-10 copy numbers of plasmid bearing the 18S rRNA sequence. The approach was verified with DNA samples from experimentally infected cattle and field samples. Thus, this assay is useful for diagnosis of bovine theileriosis in field samples and experimentally infected animals, and could also be applicable for the survey of parasite dynamics, epidemiological studies.

A Review on Equine Piroplasmosis: Epidemiology, Vector Ecology, Risk Factors, Host Immunity, Diagnosis and Control

Equine Piroplasmosis (EP) is a tick-borne disease caused by apicomplexan protozoan parasites, Babesia caballi and Theileria equi. The disease is responsible for serious economic losses to the equine industry. It principally affects donkeys, horses, mules, and zebra but DNA of the parasites has also been detected in dogs and camels raising doubt about their host specificity. The disease is endemic in tropical and temperate regions of the world where the competent tick vectors are prevalent. Infected equids remain carrier for life with T. equi infection, whilst, infection with B. caballi is cleared within a few years. This review focuses on all aspects of the disease from the historical overview, biology of the parasite, epidemiology of the disease (specifically highlighting other non-equine hosts, such as dogs and camels), vector, clinical manifestations, risk factors, immunology, genetic diversity, diagnosis, treatment, and prevention.

Development of multiplex PCR assay for concurrent detection of tick borne haemoparasitic infections in bovines

This study describes development and evaluation of a multiplex PCR assay for simultaneous detection of Theileria annulata, Babesia bigemina and Anaplasma marginale infections in bovines. The assay was developed using parasites specific genomic DNA and three sets of PCR primers targeting the Tams1, 18S rRNA and 16S rRNA genes of T. annulata, B. bigemina and A. marginale, respectively. Blood samples collected from a total of 461 bovines, suspected for haemoparasitic infections, were examined microscopically to record the status of infection and simultaneously, genomic DNA extracted from these blood samples were utilized for the optimization and validation of multiplex PCR assay. Microscopic examination of blood samples revealed presence of single and multiple species of haemoparasites in 25.8% and 2.4% samples, respectively. Results of multiplex PCR revealed the presence of single haemoparasitic species infection in 159 cases (34.5%), whereas mixed infection was recorded in 82 (17.8%) samples. Occurrence of individual species infection detected by mPCR in the study was 26.03% (120/461) for T. annulata, 3.25% (15/461) for B. bigemina and 5.20% (24/461) for A. marginale. The detection limit of multiplex PCR assay was at the template dilutions of 10-6, 10-6 and 10-4, which corresponded to 0.1 pg, 0.1 pg and 10.0 pg of DNA for T. annulata, A. marginale, and B. bigemina, respectively. Based on the high diagnostic sensitivity and throughput, multiplex PCR assay developed in the present study could be exploited as a tool to conduct large-scale epidemiological survey for tick-borne haemoparasitic infection of bovines.

Development of an indirect ELISA based on the recombinant Spm2 protein for detection of tropical theileriosis

Tropical theileriosis, caused by Theileria annulata, is distributed worldwide and causes great economic losses in dairy. The reliable diagnostic method is critical for prevention and control of the disease. In this study, a sporozoite and macroschizont gene 2 (spm2) protein from T. annulata was used to develop an indirect ELISA for tropical theileriosis. Specificity test showed that there were no cross-reactions with antibodies raised against other bovine piroplasm species using ELISA or western blotting. The specificity and sensitivity were 98.4% and 98.7%, respectively, with a threshold of 35.5% of the specific mean antibody rate (AbR). Furthermore, a total of 196 field sera samples collected from Xinjiang and Gansu provinces were detected by the spm2 ELISA and IFA. The results obtained with the spm2 ELISA and IFA in this study had the moderate agreement. The average positive rates of T. annulata sera samples detected in the present study were close to the prevalence of previous reports in these endemic areas. This indicated that the Spm2 ELISA could be used as a reliable diagnostic tool for serological survey of T. annulata infection in areas where Theileria parva is not present.

PCR diagnosis of tick-borne pathogens in Maharashtra state, India indicates fitness cost associated with carrier infections is greater for crossbreed than native cattle breeds

Tick-borne pathogens (TBP) are responsible for significant economic losses to cattle production, globally. This is particularly true in countries like India where TBP constrain rearing of high yielding Bos taurus, as they show susceptibility to acute tick borne disease (TBD), most notably tropical theileriosis caused by Theileria annulata. This has led to a programme of cross breeding Bos taurus (Holstein-Friesian or Jersey) with native Bos indicus (numerous) breeds to generate cattle that are more resistant to disease. However, the cost to fitness of subclinical carrier infection in crossbreeds relative to native breeds is unknown, but could represent a significant hidden economic cost. In this study, a total of 1052 bovine blood samples, together with associated data on host type, sex and body score, were collected from apparently healthy animals in four different agro-climatic zones of Maharashtra state. Samples were screened by PCR for detection of five major TBPs: T. annulata, T. orientalis, B. bigemina, B. bovis and Anaplasma spp.. The results demonstrated that single and co-infection with TBP are common, and although differences in pathogen spp. prevalence across the climatic zones were detected, simplistic regression models predicted that host type, sex and location are all likely to impact on prevalence of TBP. In order to remove issues with autocorrelation between variables, a subset of the dataset was modelled to assess any impact of TBP infection on body score of crossbreed versus native breed cattle (breed type). The model showed significant association between infection with TBP (particularly apicomplexan parasites) and poorer body condition for crossbreed animals. These findings indicate potential cost of TBP carrier infection on crossbreed productivity. Thus, there is a case for development of strategies for targeted breeding to combine productivity traits with disease resistance, or to prevent transmission of TBP in India for economic benefit.

Identification and Analysis of Immunodominant Antigens for ELISA-Based Detection of Theileria annulata

Tropical or Mediterranean theileriosis, caused by the protozoan parasite Theileria annulata, remains an economically important bovine disease in North Africa, Southern Europe, India, the Middle East and Asia. The disease affects mainly exotic cattle and imposes serious constraints upon livestock production and breed improvement programmes. While microscopic and molecular methods exist which are capable of detecting T. annulata during acute infection, the identification of animals in the carrier state is more challenging. Serological tests, which detect antibodies that react against parasite-encoded antigens, should ideally have the potential to identify carrier animals with very high levels of sensitivity and specificity. However, assays developed to date have suffered from a lack of sensitivity and/or specificity and it is, therefore, necessary to identify novel parasite antigens, which can be developed for this purpose. In the present study, genes encoding predicted antigens were bioinformatically identified in the T. annulata genome. These proteins, together with a panel of previously described antigens, were assessed by western blot analysis for immunoreactivity, and this revealed that four novel candidates and five previously described antigens were recognised by immune bovine serum. Using a combination of immunoprecipitation and mass spectrophotometric analysis, an immunodominant protein (encoded by TA15705) was identified as Ta9, a previously defined T cell antigen. Western blotting revealed another of the five proteins in the Ta9 family, TA15710, also to be an immunodominant protein. However, validation by Enzyme-Linked Immunosorbent Assay indicated that due to either allelic polymorphism or differential immune responses of individual hosts, none of the novel candidates can be considered ideal for routine detection of T. annulata-infected/carrier animals.

An indirect ELISA for detection of Theileria spp. antibodies using a recombinant protein (rTlSP) from Theileria luwenshuni

Theileria is a tick-borne, intracellular protozoan parasite of worldwide economic and veterinary importance in small ruminants. Here, an enzyme-linked immunosorbent assay (ELISA) was developed based on Theileria luwenshuni recombinant surface protein (rTlSP) and was used in the standardization and validation of an ELISA for the detection of circulating antibodies against ovine and caprine theileriosis. A total of 233 sera samples were used for the calculation of the cut-off value which served as a threshold between the positive and the negative sera. When the positive threshold was chosen as 19% of the specific mean antibody rate, the specificity was 97.9%, and the sensitivity was 97.1%. There was a cross-reaction with sera against Theileria uilenbergi and Theileria ovis, and no cross-reaction with sera against Babesia spp. in the ELISA and Western blotting. Two hundred forty samples collected from sheep in Gansu province were detected with blood smears and ELISA, respectively. The results showed that the positive rate of Theileria infection in Gansu province were 63.75% with rTlSP-ELISA, and 46.67% with blood smears, respectively. Our test proved that the rTlSP ELISA is suitable to diagnose Theileria infection and could be used in serological surveys to map out the prevalence of ovine and caprine theileriosis.

Spatial distribution, risk factors and haemato-biochemical alterations associated with Theileria equi infected equids of Punjab (India) diagnosed by indirect ELISA and nested PCR

Equine piroplasmosis is a febrile, tick-borne disease of equids predominately caused by obligatory intra-erythrocytic protozoa Theileria equi in the Indian sub-continent. A cross-sectional study was carried out on 464 equids (426 horses and 38 donkeys/mules) in Punjab, India to assess the level of exposure to equine piroplasmosis by 18S rRNA gene nested polymerase chain reaction (nPCR) and equine merozoite antigen-2 (EMA2) indirect-ELISA (enzyme linked immunosorbent assay), to investigate risk factors and haemato-biochemical alterations associated with the infection. The endemicity of the disease was confirmed by positive PCR amplification in 21.77% and positive antibody titers in 49.78% equid samples. There was a fair agreement between these two diagnostic techniques (Kappa coefficient=0.326). The spatial distribution analysis revealed an increasing trend of T. equi prevalence from north-eastern to south-western region of Punjab by both the techniques correspondingly, which proffered a direct relation with temperature and inverse with humidity variables. The relatively prominent risk factor associated with sero-positivity was the presence of other domestic animals in the herd, while the propensity of finding a positive PCR amplification was higher in donkeys/mules, animal kept at unorganised farm or those used for commercial purposes as compared to their counterparts. There was a significant increase in globulins, gamma glutamyl-transferase, total bilirubin, direct bilirubin, indirect bilirubin, glucose levels and decrease in total erythrocyte count, haemoglobin, packed cell volume by animals, which were revealed positive by nPCR (may or may not positive by indirect-ELISA) and increase in creatinine, total bilirubin, direct bilirubin, glucose and decrease in total erythrocytes count by animals, which were revealed positive by indirect-ELISA (alone). To our knowledge, this study, for the first time, brings out a comprehensive report on the status on spatial distribution of T. equi in Punjab (India) state, thoroughly investigated by molecular and serological techniques, evaluating various environmental and demographic risk factors along with the haemato-biochemical alterations in the exposed animals.

Diagnostic application of recombinant equine merozoite surface antigen-1 in elisa for detection of Theileria equi specific antibodies

Theileria equi merozoite surface antigens have been an important candidate for development of diagnostics. We developed ELISA based on EMA-1 recombinant antigen, so as to widen our diagnostic confidence in detection of antibodies against T. equi in sero-surveillance studies. The 547 bp EMA-1 gene fragment encoding high hydrophilic antigenic region was expressed with glutathione-S-transferase tag in prokaryotic system and purified protein (43 kDa) was used for development of ELISA (EMA-1t/ELISA). The EMA-1t/ELISA clearly differentiated T. equi-infected from Babesia caballi-infected horse sera or normal horse sera. The results of the study were validated with previously developed (EMA-2)ELISA on serum samples of known T. equi infection status and a very high correlation (0.93) was recorded between the relative percent positivity (RPP) values. Further diagnostic sensitivity of EMA-1t/ELISA was 0.92 while specificity was 1.0, indicating its suitability for sero-epidemiological studies. This assay was applied on serum samples (n = 240) collected from field horses in northern part of India. High sero-prevalence of T. equi antibodies were diagnosed in serum samples collected from Haryana state (74%) and Uttarakhand state (36.31%). Results of this study suggested that the 43 kDa EMA-1 expressed protein could be a reliable immunodiagnostic antigen in ELISA for T. equi sero-prevalence studies.

The epidemiology of tick-borne haemoparasites as determined by the reverse line blot hybridization assay in an intensively studied cohort of calves in western Kenya

The development of sensitive surveillance technologies using PCR-based detection of microbial DNA, such as the reverse line blot assay, can facilitate the gathering of epidemiological information on tick-borne diseases, which continue to hamper the productivity of livestock in many parts of Africa and elsewhere. We have employed a reverse line blot assay to detect the prevalence of tick-borne parasites in an intensively studied cohort of indigenous calves in western Kenya. The calves were recruited close to birth and monitored for the presence of infectious disease for up to 51 weeks. The final visit samples from 453 calves which survived for the study period were analyzed by RLB. The results indicated high prevalences of Theileria mutans (71.6%), T. velifera (62.8%), Anaplasma sp. Omatjenne (42.7%), A. bovis (39.9%), Theileria sp. (sable) (32.7%), T. parva (12.9%) and T. taurotragi (8.5%), with minor occurrences of eight other haemoparasites. The unexpectedly low prevalence of the pathogenic species Ehrlichia ruminantium was confirmed by a species-specific PCR targeting the pCS20 gene region. Coinfection analyses of the seven most prevalent haemoparasites indicated that they were present as coinfections in over 90% of the cases. The analyses revealed significant associations between several of the Theileria parasites, in particular T. velifera with Theileria sp. sable and T. mutans, and T. parva with T. taurotragi. There was very little coinfection of the two most common Anaplasma species, although they were commonly detected as coinfections with the Theileria parasites. The comparison of reverse line blot and serological results for four haemoparasites (T. parva, T. mutans, A. marginale and B. bigemina) indicated that, except for the mostly benign T. mutans, indigenous cattle seem capable of clearing infections of the three other, pathogenic parasites to below detectable levels. Although the study site was located across four agroecological zones, there was little restriction of the parasites to particular zones.

A duplex PCR-based assay for simultaneous detection of Trypanosoma evansi and Theileria annulata infections in water buffaloes

Trypanosomosis and bovine tropical theileriosis are important vector-borne protozoan diseases imposing some of the serious constraints on the health and productivity of domestic cattle in tropical and subtropical regions of the world. Following recovery from primary infection of both these conditions, animals become persistent carriers and act as reservoirs of infection thereby playing a critical role in disease epidemiology. The present study describes development and evaluation of duplex polymerase chain reaction (PCR) assays for simultaneous detection of Trypanosoma evansi and Theileria annulata in buffaloes. Following in silico screening for candidate target genes representing each of the pathogens, an optimized duplex PCR assay was established using TBR F/R and TAMS F/R as primer sets encoding for products of 164 and 721 bp for T. evansi and T. annulata, respectively. The results were compared and correlated with conventional Giemsa-stained thin blood smear examination and the single PCR assay. The duplex PCR detected each pathogen with the same level of sensitivity, irrespective of whether its DNA was amplified in isolation or together with DNA of another pathogen. Moreover, single and duplex PCRs were able to detect each species with equal sensitivity in serially diluted DNA representing mixtures of T. evansi and T. annulata, and no evidence of nonspecific amplification from nontarget species was observed. The developed assay may be seen as a good tool for epidemiological studies aiming at assessing the burden of dual infections and improving control of the associated diseases in endemic regions.

Direct detection of Theileria annulata in bovine blood samples using standard and isothermal DNA amplification approaches

Tropical theileriosis is a tick-borne disease responsible for important health problems in cattle, caused by the hemoprotozoan Theileria annulata. Traditionally, detection of Theileria pathogens in infected animals requires the microscopic examination of stained-blood smears and serological methods. Molecular diagnostic assays have been developed for the detection of Theileria parasites, including PCR-based and reverse line blotting approaches, but these methods usually demand qualified personnel, complex instrumentation, and expensive materials. Loop-mediated isothermal amplification (LAMP) can facilitate the design of molecular assays independent of the use of sophisticated equipment. In this chapter we describe the application of two molecular assays for the direct detection of T. annulata in bovine blood samples, based in real-time PCR and LAMP, both targeting the Tams1-encoding gene of this parasite.

Vertical transmission of Theileria lestoquardi in sheep

This is the first report of an outbreak of Theileria lestoquardi abortion and stillbirth in a mob of 450 ewes in July 2012, during which, approximately 35 late-term ewes lost their fetuses over a 5-day period. A dead ewe and her aborted fetus were transported to the Ahvaz Veterinary Hospital for the diagnostic evaluation. The microbial cultures from the ewe vaginal discharges and fetal abomasal contents and the liver were negative. The blood films of the ewe and her fetus contained Theileria piroplasms and the impression smears from ewe liver and fetal spleen were positive for Theileria Koch blue bodies. The DNA was extracted from the liver and spleen of ewe and her fetus, respectively, and analyzed by polymerase chain reaction (PCR) using specific primers derived from the nucleotide sequences of 18S ribosomal DNA (rDNA) gene of T. lestoquardi. A single fragment of 428-bp fragment was amplified. The PCR product was directly sequenced and the alignment of the sequence with similar sequences in GenBank(®) showed 100% identities with 18S rDNA gene of T. lestoquardi. The present study is the first report of the T. lestoquardi vertical transmission that could be related to the abortion.

Diagnosis of subclinical equine theileriosis in center of Iran using parasitological and molecular methods

A total of 105 blood samples from healthy horses from different stables in Yazd province, center of Iran, were examined for the presence of Theileria equi infection using parasitological and molecular methods. Out of the 105 samples, the parasitological method detected T. equi infection in 5 (4.76%) cases while the PCR method gave 24 (22.86%) positive results. Age, gender and breed were not determined as risk factors for T. equi infection in this study. Since blood samples were taken from healthy animals, this implies that 22.86% of horses had subclinical theileriosis in the current study. In conclusion, this study demonstrated that T. equi is present in horses in the center of Iran. Despite the healthy appearance of horses, these carrier animals can transmit the parasites to ticks and are a potential continuous source for maintaining and disseminating the organisms to the horse population. We concluded that it is important to make further studies on definitive host and vectors in the respective areas.

Theileria infection in domestic ruminants in northern Ethiopia

Piroplasmosis caused by different tick-borne hemoprotozoan parasites of the genera Theileria and Babesia is among the most economically important infections of domestic ruminants in sub-Saharan Africa. A survey for piroplasm infection was conducted in three locations in Northern Ethiopia. Of 525 domestic ruminants surveyed, 80% of the cattle, 94% of the sheep and 2% of the goats were positive for different Theileria spp. based on PCR of blood followed by DNA sequencing. Sheep had a significantly higher rate of infection compared with cattle (P<0.0003) and both sheep and cattle had higher rates of infection compared to goats (P<0.0001). Four species of Theileria were detected in cattle: T. velifera, T. mutans, T. orientalis complex and T. annulata with infection rates of 66, 8, 4, and 2%, respectively. This is the first report of T. annulata, the cause of Tropical Theileriosis in Ethiopia. Of the two Theileria spp. detected in small ruminants, T. ovis was highly prevalent (92%) in sheep and rare in goats (1.5%) whereas T. seperata was infrequent in sheep (2%) and rare in goats (0.4%). None of the animals were positive for Babesia spp.; however, Sarcocystis capracanis and S. tenella were detected in one goat and a sheep, respectively. The widespread distribution of Theileria spp. among cattle in northern Ethiopia including the virulent T. annulata and more mildly pathogenic T. mutans and T. orientalis, and the high infection rate in sheep with the usually sub-clinical T. ovis indicate extensive exposure to ticks and transmission of piroplasms with an important economic impact.

Evaluation of a real-time PCR test for the detection and discrimination of theileria species in the African buffalo (Syncerus caffer)

A quantitative real-time PCR (qPCR) assay based on the cox III gene was evaluated for the simultaneous detection and discrimination of Theileria species in buffalo and cattle blood samples from South Africa and Mozambique using melting curve analysis. The results obtained were compared to those of the reverse line blot (RLB) hybridization assay for the simultaneous detection and differentiation of Theileria spp. in mixed infections, and to the 18S rRNA qPCR assay results for the specific detection of Theileria parva.

Theileria parva, Theileria sp. (buffalo), Theileria taurotragi, Theileria buffeli and Theileria mutans were detected by the cox III assay. Theileria velifera was not detected from any of the samples analysed. Seventeen percent of the samples had non-species specific melting peaks and 4.5% of the samples were negative or below the detection limit of the assay. The cox III assay identified more T. parva and Theileria sp. (buffalo) positive samples than the RLB assay, and also detected more T. parva infections than the 18S assay. However, only a small number of samples were positive for the benign Theileria spp. To our knowledge T. taurotragi has never been identified from the African buffalo, its identification in some samples by the qPCR assay was unexpected.

Because of these discrepancies in the results, cox III qPCR products were cloned and sequenced. Sequence analysis indicated extensive inter- and intra-species variations in the probe target regions of the cox III gene sequences of the benign Theileria spp. and therefore explains their low detection. The cox III assay is specific for the detection of T. parva infections in cattle and buffalo. Sequence data generated from this study can be used for the development of a more inclusive assay for detection and differentiation of all variants of the mildly pathogenic and benign Theileria spp. of buffalo and cattle.

Molecular detection of Theileria spp. in sheep and vector ticks in the North Khorasan Province, Iran

A survey was carried in North Khorasan Province, Iran in 2010-2011, designed to identify Theileria spp. infections of both sheep and ticks. The tick species were also examined. Ninety sheep from different flocks were clinically examined, and blood samples and ixodid ticks were collected. Light microscopy of blood smears revealed Theileria spp. infection in 37 (41.1 %), while 74 (82.2 %) of blood samples were positive using semi-nested PCR. Theileria ovis, Theileria lestoquardi, and mixed infection were detected in 63/90 (70 %), 5/90 (5.5 %), and 6/90 (6.6 %) of samples, respectively. Of the 434 ticks that were collected, the most prevalent species was Rhipicephalus turanicus (69.3 %) followed by Hyalomma marginatum turanicum (18.4 %), Dermacentor marginatus (6.4 %), and Rhipicephalus bursa (5.7 %). The ticks were separated into 42 tick pools, and the salivary glands were dissected out in 0.85 % (w/v) saline under a stereomicroscope and examined using semi-nested PCR. Three pools of H. marginatum turanicum salivary glands were infected with T. ovis and T. lestoquardi, and one pool of R. turanicus was infected with T. ovis. Based on these results, it is concluded that the prevalence of T. ovis is higher than T. lestoquardi and that H. marginatum turanicum and R. turanicus are likely vectors of T. lestoquardi and T. ovis in this area.

A study on the prevalence of a tick-transmitted pathogen, Theileria annulata, and hematological profile of cattle from Southern Punjab (Pakistan)

The present study was carried out to determine the prevalence of Theileria annulata in large ruminants in Southern Punjab (Pakistan). Blood samples were collected from 144 large ruminants, consisting of 105 cattle and 39 buffaloes, from six districts of Southern Punjab including Multan, Layyah, Muzaffar Garh, Bhakar, Bahawalnagar, and Vehari. Data on the characteristics of the animals and herds were collected through questionnaires. The age of animals (P = 0.02), presence of ticks on animals (P = 0.02), and presence of ticks on dogs associated with herds (P = 0.05) were among the major risk factors involved in the spread of tropical theileriosis in the study area. Two different parasite detection techniques, PCR amplification and screening of Giemsa-stained slides, were compared, and it was found that PCR amplification is a more sensitive tool (19% parasite detection) as compared to smear scanning (3% parasite detection) for the detection of T. annulata. Twenty eight out of 144 animals produced the 721-bp fragment specific for T. annulata from five out of six sampling districts. Different blood (hemoglobin, glucose) and serum (ALT, AST, LDH, cholesterol) parameters of calves and cattle were measured and compared between parasite-positive and parasite-negative samples to assess the effect of T. annulata on the blood and serological profile of infected animals.

Study on acute phase proteins (haptoglobin, serum amyloid A, fibrinogen, and ceruloplasmin) changes and their diagnostic values in bovine tropical theileriosis

This study was conducted to assess the pattern of changes and the relative value of acute phase proteins (haptoglobin (Hp), serum amyloid A (SAA), ceruloplasmin and fibrinogen) in bovine tropical theileriosis. The diseased group comprised 50 dairy Holstein cattle, 2-3 years old, naturally infected with Theileria annulata. Infected animals were divided into four subgroups with different parasitemia rates (<1%, 1-3%, 3-5%, >5%). As a control group, 20 uninfected cattle were also sampled. Blood samples were collected and all measurements were done using validated methods. There were significant differences in red blood cells (RBCs), packed cell volume (PCV), hemoglobin (Hb) and concentrations of Hp, SAA, ceruloplasmin and fibrinogen between healthy cattle and those infected with T. annulata with different parasitemia rates (P < 0.05). As the parasitemia rate increased in infected cattle, a significant decrease was observed in RBCs, PCV, and Hb. In contrast, with increase in the parasitemia rate, a significant increase in the mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), Hp, SAA, ceruloplasmin, and fibrinogen was evident. The optimal cut-off point was set by the receiver operating characteristics (ROC) method to >5.68 microg/ml for SAA, >0.16 g/l for Hp, >0.064 g/l for ceruloplasmin and >4.00 g/l for fibrinogen with corresponding 84% sensitivity and 100% specificity for SAA, 76% sensitivity and 100% specificity for Hp, 84% sensitivity and 80% specificity for ceruloplasmin and 40% sensitivity and 100% specificity for fibrinogen. SAA had the highest sensitivity and specificity and was diagnosed to be a suitable indicator of APPs changes in bovine theileriosis.

Detection and differentiation of ovine Theileria and Babesia by reverse line blotting in China

A reverse line blot (RLB) assay was developed for detection and specific identification of the different ovine Theileria and Babesia parasites. In a polymerase chain reaction (PCR), the hypervariable region 4 (V4 region) of the 18S ribosomal DNA gene was amplified with a set of general primers specific for members of the genera Theileria and Babesia. Meanwhile, specific oligonucleotide probes were designed and bound on membrane. After one single-PCR amplification, the amplified fragment was hybridized against different generic and species-specific probes. It was able to detect four species, i.e., Babesia motasi (Chengde, Lintan, Ningxian, Tianzhu), Babesia sp. (Kashi), Theileria luwenshuni (Lintan, Madang, Ningxian), Theileria uilenbergi (Longde, Zhangjiachuan) as defined previously. All probes bound to their respective target sequence only; therefore, no cross-reaction was observed, resulting in clear recognition of either individual strains, species, or groups in normal positive tests. Meanwhile, no signal was observed when ovine genomic DNA and water were used as a control, demonstrating that the signals are due to the presence of parasite DNA in the samples. Furthermore, the sensitivity of RLB could be considerably enhanced to detect a parasitemia level between10(-3)% and 10(-8)%. Finally, 117 samples from field were tested with RLB, PCR, and enzyme-linked immunosorbent assay (ELISA). The positive rate of RLB was higher than that of PCR and ELISA, and furthermore, RLB could determinate the species of piroplasms, the samples were infected with. Samples, 1,117, from five areas in Gannan Tibet Autonomous Region have been examined with RLB assay and compared with ELISA assay for corresponding samples. The results showed that the positive rate of RLB was higher than that of ELISA test obviously, and both T. luwenshuni and T. uilenbergi were widely distributed in these areas. RLB developed here could be used for differentiation of Babesia and Theileria infection and for epidemiological survey, which was difficult to achieve by classical methods. In conclusion, the RLB is a versatile technique for simultaneous detection and identification of all ovine piroplasms.

A perspective on Theileria equi infections in donkeys

The donkey population has remained unchanged in the last two decades despite a decrease in the overall population of equids, emphasizing the usefulness of the donkey as a draught and pack animal. Piroplasmosis in donkeys, caused by Theileria equi and Babesia caballi, has been recognized as a serious problem of major economic importance as the affected animals manifest decreased working capacity, loss of appetite, etc. In tropical countries, T. equi infections are more wide-spread and pathogenic than those caused by B. caballi. Donkeys usually remain asymptomatic carriers with positive antibody titres throughout life. Transmission of infection occurs from animal to animal through ticks such as Hyalomma spp. Rhipicephalus spp. and Dermacentor spp. The clinical form of the disease is diagnosed by peripheral blood smear examination, but in carrier donkeys it is very difficult to demonstrate the parasite in stained blood smears as the parasitaemia is extremely low. For diagnosis of such low grade infection or carrier animals, serological tests and DNA-based molecular diagnostic techniques, which are discussed in the present review, have become mandatory. Currently, there is no suitable pharmacotherapy available to clear the T. equi infection from affected donkeys, though some new drugs and drug combinations used against this disease condition have been discussed. In the present situation, there is an urgent need for international cooperation and coordination for development of sensitive molecular diagnostic tools and effective pharmacotherapies for curtailment of the disease condition. Hence, it is imperative to develop and exchange reagents and technology developed through human resource sharing in the interest of sustainability of donkey husbandry.

Molecular detection of Theileria and Babesia infections in cattle

This study was carried out to determine the presence and distribution of tick-borne haemoprotozoan parasites (Theileria and Babesia) in apparently healthy cattle in the East Black Sea Region of Turkey. A total of 389 blood samples were collected from the animals of various ages in six provinces in the region. Prevalence of infection was determined by reverse line blot (RLB) assay. The hypervariable V4 region of the 18S ribosomal RNA (rRNA) gene was amplified with a set of primers for members of the genera Theileria and Babesia. Amplified PCR products were hybridized onto a membrane to which generic- and species-specific oligonucleotide probes were covalently linked. RLB hybridization identified infection in 16.19% of the samples. Blood smears were also examined microscopically for Theileria and/or Babesia spp. and 5.14% were positive. All samples shown to be positive by microscopy also tested positive with RLB assay. Two Theileria (T. annulata and T. buffeli/orientalis) and three Babesia (B. bigemina, B. major and Babesia sp.) species or genotypes were identified in the region. Babesia sp. genotype shared 99% similarity with the previously reported sequences of Babesia sp. Kashi 1, Babesia sp. Kashi 2 and Babesia sp. Kayseri 1. The most frequently found species was T. buffeli/orientalis, present in 11.56% of the samples. T. annulata was identified in five samples (1.28%). Babesia infections were less frequently detected: B. bigemina was found in three samples (0.77%), B. major in two samples (0.51%) and Babesia sp. in five samples (1.28%). A single animal infected with T. buffeli/orientalis was also infected with B. bigemina.

[Use of multiplex PCR for the diagnosis of Theileria annulata and Theileria buffeli]

The species causing theileriosis in cattle in Turkey are Theileria annulata and T. buffeli. While T. buffeli is low in pathogenicity or non-pathogenic , T. annulata is very pathogenic and causes tropical theileriosis with high morbidity and mortality in cattle. In this study, a multiplex PCR was used for a simultaneous diagnosis of these species. Genes for the merozoite surface antigen (Tams 1) and the major piroplasm surface protein (MPSP) were amplified with PCR for T. annulata and T. buffeli, respectively. It was found that both single and mixed infection with T. annulata and T. buffeli could be diagnosed with multiplex PCR.

[Therapeutic efficacy of buparvaquone (buparvon) in cattle with theileriosis]

The aim of this study was to examine the efficacy of buparvaquone (Buparvon, ALKE, Istanbul) in the treatment of theileriosis in cattle. The causative agent T. annulata causes direct and indirect gross economical loss in Turkey. Theileriosis was microscopically diagnosed by determining the presence of piroplasms in erythrocytes in thin blood smears stained with Giemsa stain. Buparvaquone was administered intramuscularly to the cattle with theileriosis using a single dose of 2.5 mg/kg. Clinical and laboratory examinations in cattle with theileriosis were carried out before and on the first, third and seventh days after treatment. As a result, it was concluded that a single deep intramuscular dose of 2.5 mg/kg buparvaquone was effective in the treatment of cattle which are naturally infected with T. annulata. However, further studies are needed using control groups of the same breed and age including suitable numbers of naturally infected and experimentally infected cattle.

[Molecular diagnostics of Babesia and Theileria]

Protozoa Babesia and Theileria are a group of parasites transmitted by ticks and invading mammals' blood cells. Infections by these protozoa cause heavy losses among farm animals. Since human babesiosis was described forty years ago, the number of reported cases has been increasing. Conventional methods of parasitological diagnostics are unreliable in these diseases, especially in stages with low parasitemia. Methods of nucleic acids detection have been developing fast in recent years and are more and more specific and sensitive. Polymerase Chain Reaction (PCR) enables detection of DNA of Babesia and Theileria, even in parasitemia as low as a few organisms per milliliter. Real-time PCR is useful especially in early stage of babesiosis when results of serological tests are negative and the blood smear does not reveal the pathogen or for distinction between intererythrocytic forms and Plasmodium. RLB is a method more sensitive than PCR and enabling detection of coinfections with different organisms. LAMB is a method of DNA amplification in isothermal conditions, offered as faster, easier, but still highly specific alternative to PCR. NASBA is a method where RNA of Babesia and Theileria is an initial template. The choice of a specific method highly depends on cost of laboratory equipment needed.

Comparisons among two serological tests and microscopic examination for the detection of Theileria annulata in cattle in northern Sudan

We tested the agreement between microscopic examination (ME), a surface protein-detecting enzyme-linked immunosorbent assay (TaSP ELISA) and an indirect fluorescent assay (IFA) for detection of Theileria annulata in 2,661 naturally infected cattle from northern Sudan (samples collected between June 2001 and July 2002). In the ME, we detected piroplasms in 364/2,661 cattle (14%), and the kappas between the ME and the serological tests were poor (TaSP ELISA 10%; IFA 8%). The TaSP ELISA detected 885/2,661 cattle as positive, and the Rogan-and-Gladen corrected true prevalence of this sample was estimated to be 30%. The relative sensitivity and specificity of the IFA (compared to the previously validated TaSP ELISA) were 70.7% and 81.8%, respectively.

From molecule to diagnostic tool: Theileria annulata surface protein TaSP

Isolation and characterization of the Theileria annulata macroshizont stage protein TaSP showed that this parasite surface membrane protein is a highly antigenic protein suitable for the development of diagnostic tools for tropical theileriosis. An enzyme-linked immunosorbent assay (ELISA) for the detection of circulating antibodies against Theileria annulata was established and validated using the recombinantly expressed TaSP protein. The ELISA has subsequently been applied for cross-sectional surveys to determine the distribution and prevalence of tropical theileriosis in Sudan.

Validation of the indirect fluorescent antibody and the complement fixation tests for the diagnosis of Theileria equi

The indirect fluorescent antibody (IFA) test for Theileria equi was evaluated to assess test's suitability for the serological diagnosis of equine piroplasmosis, to provide performance parameters for the purpose of test validation, and to compare it with the complement fixation (CF) test. Using a protocol that included Evan's blue, the specificity of the IFA test was estimated at 99.0% for T. equi by the classical method of analysis, and 96.6% by the Bayesian method. The use of Evan's blue in the test protocol increased test specificity and contributed to an excellent test agreement between two collaborating laboratories (kappa = 0.96). Using Bayesian analysis, the sensitivity estimate for the IFA test was 89.2%. The CF test sensitivity and specificity estimates for T. equi were 63.1 and 96.4%, respectively, as determined by Bayesian analysis. The IFA test was more sensitive than the CF test but the specificity estimates were similar.

Clinical, haematological and therapeutic studies on tropical theileriosis in water buffaloes (Bubalus bubalis) in Egypt

Thirty buffaloes naturally infected with Theileria annulata and 10 parasitologically free controls were used to determine the potential clinical, haematological and therapeutic impact of tropical theileriosis in Egypt. The clinical signs in the infected buffaloes were pyrexia (40.5-41.5 degrees C), enlargement of superficial lymph nodes, slight nasal and ocular discharges, salivation, anaemia and respiratory distress. Eye lesions also were recorded. There was a significant decrease in erythrocyte counts and haemoglobin content and a significant decrease in total leucocyte counts in infected buffaloes compared to controls. Early treatment with buparvaquone was 100% effective in eliminating the protozoan parasites from the blood and lymph nodes and led to an improvement in the clinical state whereas treatment in the later stages of the disease whilst eliminating the parasites failed to improve the clinical condition of the animal.

Serological diagnostic tools for the major tick-borne protozoan diseases of livestock

Tick-borne protozoan diseases, babesiosis and theileriosis, are among the most important diseases affecting the productivity of livestock worldwide and resulting in high economic losses. A prerequisite for the control of these diseases is to study their epidemiology by mapping their distribution and seasonality. As clinical diagnostic and surveillance tools, serological tests such as the complement fixation test (CFT), the indirect fluorescent antibody test (IFAT) and the enzyme linked immunosorbent assay (ELISA) have been successfully used over decades. With the development in molecular biology, recombinantly expressed parasite molecules have emerged and substituted crude parasite antigen used in serology. A popular format of these tests is the antibody binding competitive inhibition and the indirect antibody detection ELISA. Under the precondition that these tests are correctly designed and validated, they provide a powerful tool for epidemiology, with greater advantages of affordability and amenability to standardization. This paper reviews the pathogenic tick-borne protozoan diseases and the respective diagnostic ELISA based serological tests currently available for serosurveillance.

A review of nucleic-acid-based diagnostic tests for Babesia and Theileria, with emphasis on bovine piroplasms

Nucleic acid-based methods offer a variety of tools for the detection of parasites. This field of veterinary and medical sciences is rapidly evolving, leading to greater sensitivity and higher throughput. One of the reasons justifying such a fast development is the fact that tests targeting several taxa can be created. The present article deals with the applications of molecular diagnostics of tick-borne diseases in Parasitology. Special attention is given to Babesia and Theileria species infecting livestock. The commonly used molecular methods in diagnostic of tick-transmitted hematic protozoa are the following: (i) final time polymerase chain reaction; (ii) reverse line blotting (RLB); (iii) real time PCR, based on SYBR Green or probe fluorescence; (iv) isothermal amplification methods: loop-mediated amplification (LAMP) and self sustaining sequence replication (3SR, also named as "Nucleic Acid Sequence Based Amplification", NASBA, or Transcription Mediated Amplification, TMA). In general, none of these methods could be considered better than another. Their score in diagnostic applications greatly depends on the laboratory size. Small-scale laboratories handling few samples may find final time PCR a cheap alternative. On the contrary, large-scale laboratories prefer methods amenable to automation, like RLB, PCR-ELISA or qPCR.

Purification of macroschizonts of a Sudanese isolate of Theileria lestoquardi (T. lestoquardi [Atbara])

Research on malignant theileriosis is affected by the limited access to biological materials required for studies aiming at controlling the disease through the establishment of diagnostic tools and vaccines. The main aims of this work were to isolate, establish, and characterize a Theileria lestoquardi-infected cell culture (line) as a source of biological material and to generate a schizont cDNA library for further studies aiming at the identification of antigenic proteins. The T. lestoquardi isolate used originated from a sheep showing typical signs of malignant theileriosis in Atbara town in northern Sudan, and was maintained as an infected cell culture. A high-quality representative schizont cDNA library was established by isolating and purifying the schizonts using a nocodazole/aerolysin protocol followed by Percoll gradient ultracentrifugation. As a parameter to assess the quality of the schizont library, a provisional estimation of the percentage of recombinant phage clones originating from T. lestoquardi (Atbara) was undertaken. Ten clones with inserts ranging in size between 600 and 1200 bp were selected randomly, sequenced, and subjected to BLAST similarity searches. As 6 of the 10 sequenced clones showed similarities to T. parva, T. annulata, and other apicomplexan genes, it was concluded that the majority of the library phage clones originated from the parasite and not from host cell transcripts. The cDNA library will be used for screening of antigenic proteins using sera from infected sheep.

Identification of potential antigenic proteins of Theileria lestoquardi

A PCR strategy was used to identify potential antigenic proteins of T. lestoquardi suitable for the development of an ELISA by searching for homologous proteins previously identified in other theilierial parasites to be antigenic.

[Survey of T. annulata and T. buffeli/orientalis in cattle in the region of Erzincan using reverse line blotting]

This study was carried out to investigate Theileria annulata and T. buffeli/orientalis in cattle in the region of Erzincan using reverse line blotting (RLB) and microscopical examination. A total of 123 blood samples and thin blood smears were collected from cattle in distinct locations. Thin blood smears were microscopically examined for Theileria piroplasms. The 18S SSU rRNA gene in the DNA of Theileria spp extracted from blood was amplified and used in RLB. For this purpose, PCR products were hybridized with specific probes for over-all Theileria spp., T. annulata and T. buffeli/orientalis as well as Babesia spp. While Theileria spp. were observed in 14 out of 123 cattle, (11.38 %) during microscopical examination, T. annulata was detected in 19 (15.45%) cattle and T. buffeli/orientalis, in 12 (9.76%) by RLB, respectively. Mixed infection was also detected in three samples.

[Detection of Babesia caballi (Nuttall, 1910) and Theileria equi (Syn. Babesia equi , Laveran, 1901) by the polymerase chain reaction (PCR) in show and sport horses in the region of Ankara]

The aim of this study was to compare the diagnosis of Babesia caballi and Theileria equi by the polymerase chain reaction (PCR) and microscopic examination of blood specimens collected from show and sport horses in the region of Ankara in 2004. The blood specimens were collected from randomly selected 200 show and sport horses in the region of Ankara during the tick season as well as before and after the tick season for PCR testing. At the same time, Giemsa stained peripheral blood smears were examined for the presence of Babesia spp. and also the horses were examined for the presence of ticks. Of the 200 horse blood samples analyzed, 3% were found to be positive by microscopic examination and and 10 % (B.caballi %3; T.equi %7) by the polymerase chain reaction. The difference between these two methods was confirmed to be statistically important (p < 0,001). This is the first study in which Babesia species were investigated in horses in Turkey using the PCR method. Theileria equi was found to be more prevalent than Babesia caballi.