Multiplex PCR for diagnosis of Theileria uilenbergi, Theileria luwenshuni, and Theileria ovis in small ruminants

Differential detection of ovine Theileria species using loop-mediated isothermal amplification combined with nanoparticle-based lateral flow biosensor

Ovine theileriosis is an important tick-borne protozoan disease. It has been reported that three Theileria species are responsible for ovine theileriosis in China, which are T. luwenshuni, T. uilenbergi, and T. ovis. Here, we established three detection techniques based on loop-mediated isothermal amplification (LAMP) and nanoparticle-based lateral flow biosensor (LFB) for the infection of the three Theileria species. Three LAMP primer sets were designed targeting the nucleotide sequences of the 28S rRNA gene of T. luwenshuni, T. uilenbergi, and T. ovis. We used LAMP coupled with real-time fluorescence detection to optimize the concentrations of dNTP Mix, MgSO4, and Bst 2.0 DNA polymerase, as well as the reaction temperature of the LAMP assay, and then combined LAMP with LFB (LAMP-LFB). The entire detection assay process, including genomic DNA extraction (40 min), LAMP reaction (40 min), and LFB readout (<5 min), can be completed within 85 min. The established assays can specifically detect species of T. luwenshuni, T. uilenbergi, and T. ovis infection without cross-reaction with other Theileria, Babesia, and Anaplasma species. The detection limits of the LAMP-LFB assays for T. luwenshuni, T. uilenbergi, and T. ovis plasmid templates were 2.72 × 102 copies/μL, 2.96 × 103 copies/μL, and 3.05 × 101 copies/μL, respectively. Finally, we compared the established LAMP-LFB assay with the traditional PCR assay. The results showed that the total coincidence rates were 96.67 % (T. luwenshuni), 96.67 % (T. uilenbergi), and 93.33 % (T. ovis), respectively. In general, we developed a rapid, simple, sensitive, and specific technique for differential detection of T. luwenshuni, T. uilenbergi, and T. ovis infection in small ruminants.

Detection of Babesia spp., and Theileria spp., in sheep across diverse provinces of Iran

This study aimed to identify the diversity of Babesia and Theileria species in sheep across various regions of Iran using microscopic and molecular techniques, including species-specific PCR and enzymatic digestion. A total of 373 blood samples were collected from sheep during the tick vector activity period, from 2018 to 2021, in provinces such as Tehran, Alborz, Qazvin, Hamedan, West Azerbaijan, Kerman, and Fars. Results showed that 101 samples (27 %) exhibited piroplasms including 78 samples of Theileria spp. and 23 samples of Babesia spp. A molecular approach using general primers detected piroplasm parasites in 145 samples (38 %). Theileria ovis was notably present in 91 samples (24.39 %), followed by Theileria lestoquardi in 24 samples (6.43 %). Babesia ovis infection was detected in 30 samples (8.4 %). Despite extensive molecular evaluation, no other Babesia species, including Babesia motasi, were identified. Co-infections involving T. ovis and T. lestoquardi (4 samples; 1.07 %) and T. ovis and B. ovis (6 samples; 1.60 %) were observed. No Babesia spp. were detected in Kerman and Fars provinces, although T. ovis and T. lestoquardi were present. Blast analysis of the sequences indicated 100 % intra-species similarity, with inter-species similarities of 83.3 % (B. ovis and T. lestoquardi), 84.4 % (B. ovis and T. ovis), and 96.44 % (T. ovis and T. lestoquardi). In conclusion, B. ovis was the main cause of Babesiosis, while Theileriosis was predominantly attributed to T. ovis and T. lestoquardi. Molecular diagnostics play a key role in accurately distinguishing between these species, particularly in cases of co-infection involving Babesia spp. and Theileria spp.

A Multiplex PCR Assay for Simultaneous Detection of Giardia duodenalis, Cryptosporidium parvum, Blastocystis spp. and Enterocytozoon bieneusi in Goats

Giardia duodenalis, Cryptosporidium parvum, Blastocystis spp. and Enterocytozoon bieneusi are four common zoonotic parasites associated with severe diarrhea and enteric diseases. In this study, we developed a multiplex PCR assay for the simultaneous detection of these four zoonotic protozoans in goat stool samples and assessed its detection efficiency. Specific primers were designed from conserved gene sequences retrieved from GenBank, and the PCR conditions were optimized. Genomic DNA from 130 samples was subjected to both single-target PCR and multiplex PCR. The multiplex PCR assay successfully amplified specific gene fragments (G. duodenalis, 1400 bp; C. parvum, 755 bp; Blastocystis spp., 573 bp; E. bieneusi, 314 bp). The assay sensitivity was ≥102 copies of pathogenic DNA clones with high specificity confirmed by negative results for other intestinal parasites. The detection rates were 23.08% (30/130) for G. duodenalis, 24.62% (32/130) for C. parvum, 41.54% (54/130) for Blastocystis spp., and 12.31% (16/130) for E. bieneusi, matching the single-target PCR results. The sensitivity and predictive values were 100.00%. This multiplex PCR provided a rapid, sensitive, specific, and cost-effective approach for detecting these four parasites. It also provided essential technical support for the rapid detection and epidemiological investigation of G. duodenalis, C. parvum, Blastocystis spp., and E. bieneusi infections in goat fecal samples.

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

BACKGROUND

Tick-borne diseases cause economically significant losses to animal production globally, and anaplasmosis and theileriosis are associated with the greatest losses. However, the spread of the relevant pathogens in flocks of domesticated animals in southern Egypt is little understood. Accordingly, in this study, we aimed to determine the prevalences of Anaplasma ovis, Theileria ovis, and Theileria lestoquardi in southern Egyptian sheep and goats through blood tests, and to make a molecular characterization of the A. ovis detected in sheep targeting a specific gene.

RESULTS

We collected blood samples collected from 300 sheep and goats (n=150 /species) in Luxor Province in southern Egypt, and analyzed them for the presence of A. ovis, T. ovis and T. lestoquardi with screening by conventional and nested PCR targeting the msp4 and msp5, 18S rRNA, and merozoite surface protein genes. For A. ovis 140/300 samples (46.66%) were positive overall, with 90/150 (60%) and 50/150 (33.33%) positive samples in sheep and goats, respectively. Two major surface protein genes of A. ovis, msp4 and msp5, were sequenced using DNA extracted from sheep and goat blood samples, for phylogenetic analysis and genotyping. The msp4 gene sequence revealed no significant genetic diversity, to contrast to data on A. ovis strains from other countries. For T. lestoquardi, 8/150 (5.33%) samples were positive in sheep, but no samples were positive in goats (0%). For T. ovis, 32/150 (21.33%) samples were positive in sheep, but no samples were positive in goats (0%). Sequencing targeting the merozoite surface protein gene for T. lestoquardi and the small subunit ribosomal RNA gene for T. ovis revealed no significant genetic diversity in the study, another contrast to data on A. ovis strains from other countries.

CONCLUSION

This study provides valuable data on phylogenetic and molecular classifications of A. ovis, T. ovis and T. lestoquardi found in southern Egyptian sheep and goats. It also represents the first report on detection and molecular characterization of T. lestoquardi in southern Egyptian sheep based on the specific merozoite surface protein gene, thus providing valuable data for molecular characterization of this pathogen in southern Egypt.

Molecular prevalence and phylogeny of Anaplasma marginale, Anaplasma ovis and Theileria ovis in goats and sheep enrolled from a hill station in Punjab, Pakistan

Anaplasma marginale (A. marginale), Anaplasma ovis (A. ovis) and Theileria ovis (T. ovis) are among the most commonly reported intracellular tick borne pathogens that infect ruminants across the globe causing huge economic losses. This study aims to report the prevalence and phylogenetic evaluation of these three pathogens infecting sheep and goats (n = 333) that were enrolled from Fort Munro region in Pakistan by using msp1b, msp4 and 18S rRNA genes for A. marginale, A. ovis and T. ovis respectively. Results revealed almost similar infection rates in sheep and goats with an overall prevalence of 11% for A. marginale, 28% for A. ovis and 3% for T. ovis. Concurrent infection was also recorded, however, the number of animals infected with two pathogens (n = 24; 7.2%) was higher than infection with three pathogens (n = 2; 0.6%). Risk factor analysis revealed that sheep reared in small herds had higher A. marginale (P = 0.03) and A. ovis (P = 0.04) infection rates compared to those from large herds. In addition, it was observed that bucks (P ≤ 0.05) and tick-free goats (P ≤ 0.05) exhibited higher A. ovis infection rates than nannies. Phylogenetic analysis of all three pathogens showed that Pakistani isolates were clustered together and were closely related to previously deposited Pakistani isolates as well as with those that were reported from worldwide countries. In conclusion, we are reporting that Pakistani sheep and goats have A. marginale, A. ovis and T. ovis mediated infections and control measures should be taken against them to improve the productivity of the livestock sector.

Epidemiology and Phylogeny of Anaplasma ovis with a Note on Hematological and Biochemical Changes in Asymptomatic Goats Enrolled from Four Districts in Punjab, Pakistan

Background: Anaplasma ovis is an intra-erythrocytic gram negative rickettsial bacterium that infects small ruminants, resulting in huge economic losses worldwide. Materials and Methods: The present investigation aims at reporting the molecular prevalence of A. ovis in 1200 asymptomatic goats that were enrolled from 4 districts (Layyah, Lohdran, Dera Ghazi Khan, and Rajanpur) in Punjab, Pakistan by targeting the msp4 gene of bacterium. Risk factors associated with the prevalence of A. ovis and phylogeny of bacterium were also documented. Results: 184 out of 1200 (15%) goat blood samples were infected with A. ovis. The prevalence of the pathogen varied with the sampling sites (p = 0.005), and the highest prevalence was detected in goats from Layyah (19%) followed by Rajanpur (17%), Dera Ghazi Khan (15%), and Lohdran district (9%). The represented partial msp4 gene amplicon was confirmed by Sanger sequencing and deposited to GenBank (OP225957-59). Phylogenetic analysis revealed that the amplified isolates resembled the msp4 sequences reported from Iran, Mangolia, Sudan, and the United States. Sex and age of goats, herd composition and size, and the presence of ticks on goats and dogs associated with herds were the rick factors associated with the prevalence of A. ovis. Red blood cells, lymphocytes (%), neutrophils (%), hemoglobin, and hematocrit levels in blood and Aspartate amino transferase, urea, and creatinine levels in serum were disturbed in A. ovis infected goats when compared with uninfected animals. Conclusion: We are reporting the prevalence of A. ovis in Pakistani goats from four districts of Punjab and these data will help in developing the integrated control policies against this tick-borne pathogen that is infecting our goat breeds.

Genomic Characterization of Theileria luwenshuni Strain Cheeloo

Theileria, a tick-borne intracellular protozoan, can cause infections of various livestock and wildlife around the world, posing a threat to veterinary health. Although more and more Theileria species have been identified, genomes have been available only from four Theileria species to date. Here, we assembled a whole genome of Theileria luwenshuni, an emerging Theileria, through next-generation sequencing of purified erythrocytes from the blood of a naturally infected goat. We designated it T. luwenshuni str. Cheeloo because its genome was assembled by the researchers at Cheeloo College of Medicine, Shandong University, China. The genome of T. lunwenshuni str. Cheeloo was the smallest in comparison with the other four Theileria species. T. luwenshuni str. Cheeloo possessed the fewest gene gains and gene family expansion. The protein count of each category was always comparable between T. luwenshuni str. Cheeloo and T. orientalis str. Shintoku in the Eukaryote Orthologs annotation, though there were remarkable differences in genome size. T. luwenshuni str. Cheeloo had lower counts than the other four Theileria species in most categories at level 3 of Gene Ontology annotation. Kyoto Encyclopedia of Genes and Genomes annotation revealed a loss of the c-Myb in T. luwenshuni str. Cheeloo. The infection rate of T. luwenshuni str. Cheeloo was up to 81.5% in a total of 54 goats from three flocks. The phylogenetic analyses based on both 18S rRNA and cox1 genes indicated that T. luwenshuni had relatively low diversity. The first characterization of the T. luwenshuni genome will promote better understanding of the emerging Theileria. IMPORTANCE Theileria has led to substantial economic losses in animal husbandry. Whole-genome sequencing data of the genus Theileria are currently limited, which has prohibited us from further understanding their molecular features. This work depicted whole-genome sequences of T. luwenshuni str. Cheeloo, an emerging Theileria species, and reported a high prevalence of T. luwenshuni str. Cheeloo infection in goats. The first assembly and characterization of T. luwenshuni genome will benefit exploring the infective and pathogenic mechanisms of the emerging Theileria to provide scientific basis for future control strategies of theileriosis.

Molecular prevalence and associated risk factors of Anaplasma ovis in Pakistani sheep

Background

Majority of Pakistani population lives in rural areas and raising animals, especially the small ruminants, is their primary source of income. Anaplasma ovis is known to infect small ruminants globally and causing significant economic losses to livestock owners, however prevalence of Anaplasma ovis has been least investigated from Pakistan despite having a huge sheep population.

Methods

The present study was conducted from June 2021 till December 2021 to report the PCR based prevalence of Anaplasma ovis in the blood samples of sheep (n = 239) that were collected from District Dera Ghazi Khan in Pakistan.

Results

Out of 239 samples, 30 (12.5%) amplified a 347 bp fragment specific for the msp4 gene of Anaplasma ovis. Represented partial msp4 gene sequences were confirmed by Sanger sequencing and deposited to GenBank (OP620757-59). None of the studied epidemiological factors (age, sex, breed, size of herd, dogs with herd, and composition of herd) showed an association (P &gt; 0.05) with the Anaplasma ovis infection in enrolled sheep. Analysis of the amplified partial mSP4 sequence of Anaplasma ovis revealed that this gene is highly conserved as all three sequences were identical and phylogenetically resembled with the msp4 sequences amplified from small ruminants in China, Kenya, and Germany, Turkey, Portugal, Tunisia and India. In conclusion, for the first time, we are reporting a moderate prevalence of Anaplasma ovis prevalence in Pakistani sheep and this data will help in developing the integrated control policies against this newly reported tick-borne disease that is infecting our sheep breeds.

Molecular detection and characterisation of Theileria in hard ticks of small ruminants in Zarrin Dasht County, Southern Iran

BACKGROUND

Ticks are important ectoparasites of small ruminants in tropics and subtropics including Iran. They transmit serious zoonotic pathogens such as Babesia and Theileria. These parasites cause major burden on small ruminants jeopardising livelihoods of rural people in Zarrin Dasht County.

OBJECTIVES

This study was carried out to investigate the diversity and distribution of hard ticks of small ruminants and their piroplasm infection in a bid to contribute to Theileria and/or Babesia detection and control in Zarrin Dasht County of Fars province, Iran.

METHODS

We examined 751 sheep and goats from 10 sites of the County during four seasons for hard tick infestation. The collected hard ticks (994) were taxonomically identified before being separately confined in microtubes coded to indicate their species and host animals as well as site and date of collection. In total 50 pooled samples were analysed by PCR technique for Theileria and Babesia infection.

RESULTS

The identified ticks included Hyalomma marginatum 994/362); 36.4%), Rhipicephalus turanicus 994/352); 35.51%), Hyalomma anatolicum 994/264); 26.6%), Hyalomma dromedarii 994/14); 1.41%) and Hyalomma asiaticum 994/2) 0.2%). Molecular analyses showed that 7 out of 50 pooled sample were infected with piroplasm genome in ticks shared by Theileria ovis (6:50) and Theileria lestoquardi (1:50). Babesia was absent in collected hard ticks.

CONCLUSIONS

This is the first report on the presence of piroplasm infection in hard ticks of small ruminants in Zarrin Dasht County. Theileria ovis was more prevalent than Theileria lestoquardi but Babesia was absent. Piroplasm infection was detected in Hyalomma marginatum, Hyalomma anatolicum and Rhipicephalus turanicus. Hyalomma marginatum appears to be more competent to vector Theileria spp. This study may contribute to risk assessment and prevention of epizootic theileriosis in the County.

Identification of Theileria spp. and investigation of hematological profiles of their infections in goats in Hainan Island, China

Theileria spp. are a group of parasites primarily transmitted by ticks and can pose a significant threat to domestic and wild animals globally. The main objective of this study was to understand the epidemiology of Theileria spp. in goats of Hainan Island/province, which is the only tropical region of China, and to study their hematological profiles in naturally infected goats. A total of 464 blood samples were collected from randomly selected local adult goats (Capra hircus, local domestic breed with black hair), from six cities and eight counties of Hainan, from November 2017 to October 2020. Blood smear microscopy of the sample and a nested polymerase chain reaction (nPCR) targeting the 18S rRNA gene combined with DNA sequencing were used to detect piroplasm infections in goats. Data analysis of the obtained sequences revealed that all the sequences were highly similar to the Theileria luwenshuni 18S rRNA gene sequence from the database. This result is consistent with the microscopic examination. In the hematological test, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin of the goats naturally infected with T. luwenshuni significantly increased, while mean corpuscular hemoglobin concentration and red blood cell distribution width (RDW) were significantly decreased. Results showed that T. luwenshuni could cause macrocytic, hypochromic anemia in goats. This study provides reliable and comprehensive information about the epidemiology of the parasite infections and hematological profile of the infected goats in Hainan, which encourages further investigations to develop practical control strategies for Theileria spp. infections in tropical areas.

Development of a duplex PCR assay for detecting Theileria luwenshuni and Anaplasma phagocytophilum in sheep and goats

Coinfections with the tick-borne pathogens Theileria luwenshuni and Anaplasma phagocytophilum can cause significant economic losses in sheep and goat farming. The difficulty in detecting these two pathogens by microscopic examination warrants the development of a rapid detection test to discriminate them. In this study, a duplex polymerase chain reaction (PCR) assay was developed to simultaneously detect T. luwenshuni and A. phagocytophilum. Alignment of the sequences from related pathogens allowed us to design a primer pair targeting the 18S ribosomal RNA gene in T. luwenshuni and generate a target product of 962 bp, whereas a previously reported species-specific primer (SSAP2f/SSAP2r) for A. phagocytophilum was used in the same reaction to generate a product of 641 bp. Genomic DNA from T. luwenshuni and A. phagocytophilum was 10-fold serially diluted for testing PCR sensitivity. Under the optimal PCR conditions we established, the lower limit of detection of the assay was 29.13 fg/μL for T. luwenshuni and 1.53 fg/μL for A. phagocytophilum, and PCR primers used in this study were confirmed to be 100% species-specific using other hemoparasites previously identified by other methods. No significant difference was found between conventional and duplex PCR protocols used to detect the two species. Our study provides an effective, sensitive, specific, and accurate tool for the diagnosis and epidemiological surveillance of mixed infections of the two pathogens in sheep and goats.

Mitochondrial genome of Theileria uilenbergi endemic in sheep and goats in China

Mitochondrial genomes provide new insights that help elucidating biological features, genetic evolution, and classification of protozoans. Theileria uilenbergi (T. uilenbergi), transmitted by Haemaphysalis qinghaiensis and H. longicornis, is considered as highly pathogenic to sheep and goats in China. This study reports and outlines features of its mitochondrial genome. The T. uilenbergi mitochondrial genome is a linear monomeric molecule of 6.0 kb length, which encodes three protein-coding genes named cytochrome c oxidase I (cox1), cytochrome b (cob), and cytochrome c oxidase III (cox3), as well as six large subunit (LSU) rRNA gene fragments, and ends in terminal inverted repeats (TIRs). The array structure and organization of the mitochondrial genome of T. uilenbergi is identical to that of T. parva. Phylogenetic analysis based on the amino acid sequences of cox1, cob, and cox3 genes suggests that T. uilenbergi is distantly related to the group of transforming Theileria species such as T. parva. This study contributes to a comprehensive understanding of the phylogeny and evolution of the mitochondrial genome of piroplasms and provides useful information of diagnostic marker for T. uilenbergi.

Development of a novel multiplex PCR assay for the detection and differentiation of Plasmodium caprae from Theileria luwenshuni and Babesia spp. in goats

Intraerythrocytic parasites are traditionally identified by the microscopic examination of Giemsa-stained blood smears. However, this method does not always allow for the identification of individual species in goat's RBCs. Moreover, its unreliability in detecting low levels of parasitemia makes it unsuitable for epidemiological investigations and leaves goat farms vulnerable to potential outbreaks. In the present study, a novel multiplex PCR (mPCR) targeting the cytochrome c oxidase subunit I (COI) gene was developed to detect and subsequently differentiate Plasmodium caprae, Theileria luwenshuni, and Babesia spp. The specificity of each primer set was assessed both in silico and with a panel of DNA samples from the hosts themselves and other goat hemoparasites. Amplicons generated from each pair of primers were 664, 555, and 320-bp for P. caprae, Babesia spp., and T. luwenshuni, respectively. These products were further confirmed by sequencing. Our novel mPCR reactions successfully demonstrated the accurate and simultaneous amplification of the three parasites' DNA samples. The current mPCR method showed no cross-amplification with unintended targets. The detection limit of the mPCR in this study was 10⁸ parasites' DNA copies per reaction. The current mPCR was able to detect the minimum parasitemia of approximately 0.001%, 0.000005%, 0.00001% for P. caprae, Babesia spp. and T. luwenshuni, respectively. The diagnostic specificity in the detection of P. caprae and T. luwenshuni ranged from 94.9 to 100 %. The mPCR was further applied to a collection of field blood samples from five provinces in Thailand to validate its reliability and applicability. The results demonstrated the successful detection of P. caprae, Babesia spp. and T. luwenshuni in goat samples with the same sensitivity levels as conventional PCR methods. This study also confirmed the presence of T. luwenshuni and Babesia spp. in Thai goats. The current mPCR method offers an alternative for the diagnosis of P. caprae, T. luwenshuni, and Babesia spp., either single or under co-infection conditions, and for large-scale surveillance.

Phylogenetic study of Theileria ovis and Theileria lestoquardi in sheep from Egypt: Molecular evidence and genetic characterization

Background and Aim

Ovine theileriosis caused by Theileria ovis and Theileria lestoquardi is an important infectious disease affecting small ruminants in regions of the tropic and subtropic zones. There is limited studies about ovine theileriosis in Egypt; so the present study aims to assess the occurrence of ovine theileriosis in Egypt at the molecular level.

Materials and Methods

Blood samples were collected from 115 randomly selected sheep, which were apparently healthy; the ages of the sampled sheep ranged from 1 to 5 years old, from a local breed (barkae and balade), and showed no symptoms indicating infection with Theileria spp. The study was conducted in three governorates representing Lower Egypt (Menoufia and Beheira) and Upper Egypt (El-Wady El-Geded). All blood samples were subjected to polymerase chain reaction (PCR) and semi-nested PCR to target Theileria spp. 18S rRNA genes. Positive samples were sequenced, and these sequences were analyzed using nucleotidebasic local alignment search tool (BLAST).

Results

Six animals (5.22%) were PCR-positive carriers for ovine theileriosis. Nucleotide BLAST and phylogenetic analyses of the six obtained sequences showed that T. ovis was present in five animals (4.37%) in Menoufia (n=2) and El-Wady El-Geded (n=3), whereas T. lestoquardi was detected in 1 animal (0.87%) in El-Wady El-Geded.

Conclusion

This study is the first to provide molecular evidence, genetic characterization, and phylogenetic analysis of ovine Theileria spp. in Egypt. Specifically, T. lestoquardi and T. ovis carrier statuses of sheep were confirmed. These results highlight the importance of developing an effective control strategy against ovine theileriosis carriers that might develop and/or spread theileriosis.

Molecular prevalence, characterization and associated risk factors of Anaplasma spp. and Theileria spp. in small ruminants in Northern Pakistan

This study was conducted in four districts (Malakand, Swat, Bajaur and Shangla) of Northern Pakistan to investigate the prevalence, associated risk factors and phylogenetic analyses of Theileria and Anaplasma species in small ruminants. A total of 800 blood samples, 200 from each district, were collected from apparently healthy animals. PCR assays were performed using generic primers for Anaplasma spp. and Theileria spp. as well as species specific primers for A. ovis and T. ovis. Overall infection prevalence was 361/800 (45.1%). Theileria spp. infection prevalence (187/800, 23.3%) was higher than Anaplasma spp. (174/800, 21.7%). Amplified partial 18S rRNA genes were sequenced and enrolled animals were found to be infected by T. ovis (115/800, 14.3%), and at least two more Theileria species (72/800, 9%) were present (T. lestoquardi and T. annulata). All blood samples that were found to be positive for Anaplasma spp. were also positive for A. ovis. Infection prevalence was higher in sheep (227/361, 28.3%) compared to goats (134/361, 16.6%) (p < 0.005). Univariable analysis of risk factors showed that host, age, grazing system and acaricide treatment were significant determinants (p < 0.05) for both Theileria and Anaplasma infections. Multivariable analysis revealed that host, sex, age, tick infestation and grazing system were significant risk factors (p < 0.005) for both pathogens. Phylogenetic analysis revealed variants among the A. ovis and T. annulata samples analysed, indicating that different genotypes are circulating in the field while T. ovis presented the same genotype for the samples analysed.

Molecular characterization of tick-borne bacteria and protozoans in yaks (Bos grunniens), Tibetan sheep (Ovis aries) and Bactrian camels (Camelus bactrianus) in the Qinghai-Tibetan Plateau Area, China

Due to the specific plateau climate, a variety of unique animals live in the Qinghai-Tibetan Plateau Area (QTPA) including yaks (Bos grunniens), Tibetan sheep (Ovis aries) and Bactrian camels (Camelus bactrianus). However, information on tick-borne diseases (TBDs) in the QTPA and on the molecular characteristics of tick-borne pathogens (TBPs) in the area is limited. Therefore, the aim of this study was to investigate Anaplasma spp., Babesia spp., Theileria spp., Borrelia burgdorferi sensu lato and Rickettsia spp. infecting yaks, Tibetan sheep and camels in this area. A total of 276 animals were screened. Overall, 84.5% (164/194) of yaks, 58% (23/40) of Tibetan sheep, and 38% (16/42) of camels tested positive for at least one pathogen. Theileria spp., Anaplasma ovis and spotted fever group (SFG) Rickettsia spp. were detected as TBPs in the current study with overall infection rates of 10.9% (30/276), 8.3% (23/276) and 62.9% (171/276), respectively. Further study revealed that 1.5% (3/194) of the yaks were infected with Theileria sp. OT3, 1.5% (3/194) with T. luwenshuni, 6.2% (12/194) with T. uilenbergi, 1.1% (2/194) with T. ovis and 82% (159/194) with SFG Rickettsia spp. It was also shown that 58% (23/40) of the Tibetan sheep were infected with A. ovis and 15% (6/40) with T. ovis. Among the camels, 10% (4/42) were infected with T. equi, while 29% (12/42) were positive for Rickettsia spp. Sequence analysis revealed that the Rickettsia spp. infecting yaks and camels were Rickettsia raoultii and Rickettsia slovaca. To the best of our knowledge, this study reports the first detection and characterization of these pathogens in yaks, Tibetan sheep and camels in the country, except for T. luwenshuni infections in yaks.

Theileria ovis (Piroplasmida: Theileriidae) Detected in Melophagus ovinus (Diptera: Hippoboscoidea) and Ornithodoros lahorensis (Ixodida: Argasidae) Removed From Sheep in Xinjiang, China

Theileria spp. are tick-transmitted, intracellular apicomplexan protozoan parasites that infect a wide range of animals and, as such, can cause significant economic losses. The aim of the present study was to detect and analyze apicomplexan parasites from two different ectoparasites that were collected from Xinjiang Uygur Autonomous Region, China. The PCR-based detection of 18S rRNA indicated that Ornithodoros lahorensis specimens from Kashgar, Xinjiang, and Aksu were positive for Theileria spp., as were Melophagus ovinus specimens from Aksu. Meanwhile, phylogenetic analysis, based on the 18S rRNA gene sequences, revealed that the four amplified Theileria sequences could be attributed to T. ovis. To the best of our knowledge, this is the first study to report the detection of T. ovis DNA in M. ovinus and the first molecular identification study to confirm the detection of T. ovis in O. lahorensis in China. Accordingly, the present study extends the known distribution of T. ovis.

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.

MOLECULAR CHARACTERIZATION OF THEILERIA SPP. IN GOATS FROM SHAANXI PROVINCE, NORTHWESTERN CHINA

Theileriosis is an important tick-borne pathogen of livestock globally, causing severe reduction of livestock productivity and economic loss. To systematically investigate the prevalence and species of Theileria spp. in goats from Shaanxi province, a total of 509 blood samples were collected from dairy, cashmere and meat goats from 7 counties, and examined by using the microscopic examination and the nested PCR targeting the SSU rRNA gene. Of them, 268 (52.7%, 268/509) were positive for Theileria infection. The prevalence was closely associated with ages and production categories. The highest infection was found in meat goats of 7 to 12-months, and lowest was detected in cashmere goats of 3 to 6 months. Sequence analysis indicated the presence of 2 Theileria species, with Theileria luwenshuni as the prevalent species and the first report of Theileria sp. OT3 in goats in China. These findings indicated the wide distribution of Theileria spp. in goats of Shaanxi province, and would shed new light on the distribution of this parasite in China.

Prevalence of Theileria and Babesia species in Tunisian sheep

In this study, the prevalence of Theileria and Babesia species in sheep was assessed with Giemsa-stained blood smear examination and polymerase chain reaction to identify the different piroplasms in 270 sheep from three Tunisian bioclimatic zones (north, centre, and south). The overall infection prevalence by Babesia spp. and Theileria spp. in Giemsa-stained blood smears was 2.9% (8/270) and 4.8% (13/270) respectively. The molecular results showed that sheep were more often infected by Theileria ovis than Babesia ovis with an overall prevalence of 16.3% (44/270) and 7.8% (21/270) respectively (p = 0.01). The molecular prevalence by Babesia ovis was significantly higher in females than in males (p < 0.05). According to localities B. ovis was found exclusively in sheep from the centre of Tunisia (Kairouan) whereas Theileria ovis was found in all regions. Infections with T. ovis and B. ovis were confirmed by sequencing. The sequence of T. ovis in this study (accession numbers KM924442) falls into the same clade as T. ovis deposited in GenBank. The T. ovis amplicons (KM924442) showed 99%–100% identities with GenBank sequences. Moreover, comparison of the partial sequences of 18S rRNA gene of B. ovis described in this study (KP670199) revealed 99.4% similarity with B. ovis recently reported in northern Tunisia from sheep and goats. Three nucleotides were different at positions 73 (A/T), 417 (A/T), and 420 (G/T). It also had 99% identity with B. ovis from Spain, Turkey and Iraq. The results suggest a high T. ovis prevalence in Tunisia with a decreasing north-south gradient. This could be correlated to the vector tick distribution.

Identification of piroplasm infection in questing ticks by RLB: a broad range extension of tick-borne piroplasm in China?

Sensitive and specific diagnostic method for rapid and simultaneous detection and discrimination of the different species is needed for an effective control of piroplasmosis. Here, a reverse line blot (RLB) assay was developed for piroplasm detection. A general pair of primer based on 18S ribosomal RNA (rRNA) gene was used to amplify V4 region of 18S rRNA gene. General and specific probes for 13 piroplasm species were cited from previous publications or designed according to the alignment of 18S rRNA gene sequences. For sensitivity test of RLB assay, serially diluted plasmids of the different species were used to access the sensitivity of the RLB. Four hundred and fifty tick samples collected from grass from different provinces of China were then detected. The result indicated that the RLB assay is highly specific and sensitive, detecting up to 10(2) copies/μl of recombinant plasmid DNA. Multiple piroplasms were detected as single or mixed infection from tick species. Eight piroplasm species, most of which were Theileria annulata (33/450, 7.3 %) or Babesia sp. Xinjiang (30/450, 6.7 %), were found to infect with 89 tick samples in four tick species; no infections with Babesia major, Babesia ovata, Babesia bigemina, Theileria sergenti, or Theileria equi were detected. The piroplasms species-specific RLB assay may have potential clinical application in the simultaneous detection and differentiation of Babesia and Theileria species.

Development of an immunochromatographic strip for the serodiagnosis of Theileria infection in sheep

Background

Theileria uilenbergi and T. luwenshuni are tick-borne protozoan parasites, transmitted by Haemaphysalis qinghaiensis and H. longicornis, respectively. They are the main causative agents of theileriosis in small ruminants in China. The disease has resulted in severe economic losses and hindered the development of sheep and goat husbandry industry in the endemic regions.

Methods

In this study, a colloidal gold-based immunochromatographic strip (ICS) was developed for the detection of T. uilenbergi and/or T. luwenshuni infections. A recombinant T. uilenbergi immunodominant protein (rTuIP) was used as antigen for the ICS. The nitrocellulose membrane was incubated with rTuIP on the test (T) line and anti-rTuIP antiserum on the control (C) line, respectively. The rTuIP conjugated to colloidal gold particles was used as the detection system for visualization of the lines. Then the sample pad, conjugate pad, nitrocellulose membrane and absorbent pad were assembled onto a backing plate in the appropriate order.

Results

The ICS was able to detect antibodies in the sera of animals experimentally infected with T. uilenbergi from 14 to 85 days. It also reacted with the serum from T. luwenshuni infected sheep. However, there was no cross-reactivity with sera from animals infected with Babesia motasi and Anaplasma ovis. Comparison of the ICS with the rTuIP antigen based indirect enzyme-linked immunosorbent assays (ELISA) using test field samples showed good correlations with 93.1 % (81/87) sensitivity and 100 % (40/40) specificity, respectively, with an almost perfect agreement (Kappa = 0.895, P < 0.01).

Conclusion

An immunochromatographic strip test based on a recombinant T. uilenbergi immunodominant protein (rTuIP) was developed. This is a rapid test (approximately 15 min to completion) for the detection of T. uilenbergi and/or T. luwenshuni infection that is easy to perform and; delivers results that are visible to the naked eye.

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

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

A review of Theileria diagnostics and epidemiology

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

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

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

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

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Parasitemia ranges may determine practical limits of detection.

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

A pan-Theileria FRET-qPCR survey for Theileria spp. in ruminants from nine provinces of China

Background

Theileria spp. are tick transmitted protozoa that can infect large and small ruminants causing disease and economic losses. Diagnosis of infections is often challenging, as parasites can be difficult to detect and identify microscopically and serology is unreliable. While there are PCR assays which can identify certain Theileria spp., there is no one PCR that has been designed to identify all recognized species that occur in ruminants and which will greatly simplify the laboratory diagnoses of infections.

Methods

Primers and probes for a genus-specific pan-Theileria FRET-qPCR were selected by comparing sequences of recognized Theileria spp. in GenBank and the test validated using reference organisms. The assay was also tested on whole blood samples from large and small ruminants from nine provinces in China.

Results

The pan-Theileria FRET-qPCR detected all recognized species but none of the closely related protozoa. In whole blood samples from animals in China, Theileria spp. DNA was detected in 53.2% of the sheep tested (59/111), 44.4% of the goats (120/270) and 30.8% of the cattle (380/1,235). Water buffaloes (n = 29) were negative. Sequencing of some of the PCR products showed cattle in China were infected with T. orientalis/T. sergenti/T. buffeli group while T. ovis and T. luwenshuni were found in sheep and T. luwenshuni in goats. The prevalence of Theileria DNA was significantly higher in Bos p. indicus than in Bos p. taurus (77.7% vs. 18.3%) and copy numbers were also significantly higher (10^4.88 vs. 10^3.00Theileria 18S rRNA gene copies/per ml whole blood).

Conclusions

The pan-Theileria FRET-qPCR can detect all recognized Theileria spp. of ruminants in a single reaction. Large and small ruminants in China are commonly infected with a variety of Theileria spp.

Detection of piroplasms infection in sheep, dogs and hedgehogs in Central China

BACKGROUND

Piroplasms are kinds of tick-borne parasitic apicomplexan protozoa, which are detrimental to humans and animals in tropical and subtropical areas around the world. Up until now, there has been a limited amount of reliable information available about the prevalence of piroplasms infections in wild animals in China. Therefore, we have investigated the infections of Babesia and Theileria species in both domestic and wild animals in Xinyang city, Henan province, where tick-borne diseases have recently been reported. This study aims to analyze the distribution patterns of piroplasms infections in animals, and assess their potential threat to humans in Central China.

METHODS

Blood samples were collected from sheep, dogs and hedgehogs in two regions, including Shihe District and Luoshan County, of Xinyang city, Henan province from August to December 2012. Babesia spp. and Theileria spp. were detected by polymerase chain reaction (PCR) and identified by sequencing and phylogenetic analysis. Moreover, the characteristics of detected piroplasms in different animal hosts were compared between the two study regions.

RESULTS

A total of 227 blood samples were collected from 73 sheep, two dogs and 152 hedgehogs. Babesia spp. was only detected in the two dogs. Theileria spp. was detected both in the sheep and the hedgehogs, and the total positive rate of Theileria spp. in the sheep and the hedgehogs was 57.53% and 13.82%, respectively. Sequencing and phylogenetic analysis revealed that the Theileria spp. detected in the sheep and the hedgehogs were very close to T. lunwenshuni cloned from a small ruminant and Theileria spp. isolated from a febrile hospitalized patient in China.

CONCLUSION

Babesia and Theileria infections were detected in both domestic and wild animals in Xinyang city, Henan province in Central China, thus warranting further studies in these regions.