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

Assessment of Tick-Borne Diseases in Hainan Province, China

China's six tropical regions include Guangdong Province, Yunnan Province, Hainan Province, Hong Kong Special Administrative Region (SAR), Macau SAR, and Taiwan, China. Hainan, seated in the southernmost tropical region of China, is home to ticks that remain active throughout all four seasons. This heightens their potential to transmit tick-borne diseases to both animals and humans. This study provides a succinct overview of the prevailing tick species' spatial distribution and offers an outline of the range and dispersion of emerging tick-borne infections in tick vectors, animal hosts, and human populations within Hainan, China.

Detection of Babesia spp., Theileria spp., and Anaplasma ovis in Ornithodoros lahorensis from southern Xinjiang, China

Introduction

Ticks are blood-sucking arthropods that have negative economic impacts and can spread a variety of diseases through their bites. There are few reports on soft ticks (Acari: Argasidae) and tick-borne pathogens in southern Xinjiang, China. This investigation supplements the available information for this region and is concerned with an argasid tick, apicomplexan parasites of the Babesia and Theileria genera and a bacterium of the Anaplasma genus.

Material and Methods

In this study, 330 soft ticks were collected from nine sampling sites in southern Xinjiang between 2020 and 2021. The ticks were identified according to their morphological characteristics and confirmed as Ornithodoros lahorensis using mitochondrial 16S rDNA sequences. Babesia and Theileria were identified at the species level based on two fragments of the 18S rRNA gene, and one set of primers targeting the 16S rRNA gene was used to identify the Anaplasma genus.

Results

Among the 330 samples, one Babesia species (Babesia sp.), two Theileria species (T. ovis and T. annulata), and one Anaplasma (A. ovis) species were detected.

Conclusion

This study provides fundamental evidence for the occurrence of Babesia, Theileria and Anaplasma spp. in soft ticks. To the best of our knowledge, this is the first report of the detection of Babesia sp. and T. annulata in O. lahorensis. Therefore, the potential threat of soft ticks to livestock and humans should not be ignored.

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

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

Prevalence of Theileria in cattle in China: A systematic review and meta-analysis

Theileria, one of the causative agents of blood protozoan, has brought a huge economic loss to the cattle industry worldwide. However, the epidemiology of Theileria in Chinese cattle has not been systematically investigated. This comprehensive review aimed at investigating the prevalence of Theileria infection in cattle in China. A total of 48 published papers on Theileria infection in cattle in China (including data from 21,366 animals) from inception to October 8, 2021 met the inclusion standard after searching in five databases (Technology Periodical Database, Wan Fang Database, China National Knowledge Infrastructure, PubMed, and ScienceDirect). The pooled prevalence of Theileria in cattle in China was 32.4% identified by using a random effects model. The prevalence in Northeastern China (45.3%) was higher than that in other regions. In the sex subgroup, the prevalence of Theileria was higher in females (48.9%) than that in males (45.8%). The prevalence of Theileria was higher in cattle of free range (34.4%) compared with that of intensive farming (22.3%). The prevalence prior to 2013 (36.1%) was higher than that after 2013 (33.6%). Among three cattle species, dairy cows had the lowest prevalence (21.5%). The prevalence of Theileria (T.) annulata (22.2%) and T. sergenti (26.2%) was higher than other species of Theileria (T. buffeli: 17.5%, T. luwenshuni: 0.9%, T. orientalis: 15.5%, T. ovis: 0.21%, T. sinensis: 20.2%, T. uilenbergi: 6.2%, Others: 0.9%). We also analyzed the impact of different geographic factor subgroups (longitude, latitude, precipitation, temperature, humidity, and altitude) on the prevalence of Theileria in cattle. Among them, climatic factors of longitude, latitude, precipitation, humidity, temperature were associated with the prevalence of Theileria. These analyses suggested that Theileria was common in cattle in China. Targeted prevention programs based on geographic and climatic conditions in different areas may play an important role in reducing Theileria infection among cattle.

Genetic Diversity of Bovine Hemoprotozoa in South Korea

Tick-borne pathogens cause economically significant diseases in cattle. Theileria spp. are parasitic protozoa and the causative agent of bovine theileriosis. Here we report the distribution and risk factors of bovine Theileria using blood samples taken between 2018 and 2019. Of 737 tested cattle, nine animals (1.2%) were positive for Theileria orientalis infection by 18S rRNA gene amplification. Further analysis of the infected samples using the T. orientalis major piroplasm surface protein (MPSP) gene revealed five different genotypes circulating in the population: Types 1, 2, 3, 7, and N3. To the best of our knowledge, this is the first research to describe the existence of the T. orientalis MPSP genotype N3 in South Korea. Although the prevalence of bovine T. orientalis was low, our study offers data on the geographical distribution and prevalence of bovine Theileria spp. in South Korea. Further studies are warranted to determine the correlation of clinical symptoms with parasite MPSP genotypes. Our data provide epidemiological information to help control bovine theileriosis in South Korea.

Molecular Detection, Phylogenetic Analysis, and Genetic Diversity of Theileria annulata, Babesia bigemina, and Anaplasma marginale in Cattle in Three Districts of Egypt

BACKGROUND

Under the poor hygienic conditions, tick-borne pathogens cause severe economic losses to the cattle industry.

PURPOSE

The current study investigated the presence of Theileria annulata, Babesia bigemina, and Anaplasma marginale, the most relevant tick-borne pathogens in cattle, in 3 provinces of Egypt utilizing species-specific PCR assays.

METHODS

PCR was conducted, on bovine blood specimens, using primers targeting the T. annulata merozoite-piroplasm surface antigen (Tams1, 768 bp), A. marginale major surface protein-1b gene (msp1b, 265 bp), and B. bigemina small subunit ribosomal RNA gene (SSrRNA, 543 bp).

RESULTS

PCR findings revealed overall prevalences of T. annulata, B. bigemina, and A. marginale as 22.0% (33/150), 19.33% (29/150), and 10.6% (16/150), respectively. The co-infection with two or three pathogens was detected in 20.0% (30/150) of examined specimens. Sequence analyses indicated that T. annulata and A. marginale varied from those of corresponding GenBank sequences revealing percent identities ranging from 90.68 to 97.75% and from 94.98 to 98.63%, respectively. On the other hand, the obtained B. bigemina sequences showed a high similarity with those previously reported in GenBank with a percent identity ranging from 98.85 to 100%.

CONCLUSION

T. annulata was the most prevalent tick-borne pathogen in examined bovine specimens. The genetic diversity of markers used for identification of T. annulata and A. marginale should be highly considered.

Genetic Diversity of Babesia bovis MSA-1, MSA-2b and MSA-2c in China

The apicomplexan parasite Babesia bovis is a tick-borne intracellular hemoprotozoan parasite that is widespread across China. Genetic diversity is an important strategy used by parasites to escape the immune responses of their hosts. In our present study, 575 blood samples, collected from cattle in 10 provinces, were initially screened using a nested PCR (polymerase chain reaction) for detection of B. bovis infection. To perform genetic diversity analyses, positive samples were further amplified to obtain sequences of three B. bovis merozoite surface antigen genes (MSA-1, MSA-2b, MSA-2c). The results of the nested PCR approach showed that an average of 8.9% (51/575) of cattle were positive for B. bovis infection. Phylogenetic analyses of the predicted amino acid sequences revealed that unique antigen variants were formed only by Chinese isolates. Our findings provide vital information for understanding the genetic diversity of B. bovis in China.

Molecular Survey and Genetic Diversity of Babesia spp. and Theileria spp. in Cattle in Gansu Province, China

PURPOSE

Babesia spp. and Theileria spp. are tick-borne pathogens of livestock globally. In this study, we investigated the presence and distribution of these pathogens in cattle from 20 locations in 4 Counties of Wuwei City. The aim of the present research was to evaluate the spread of piroplasms, so as to provide the epidemiological information for control piroplasmosis in the region.

METHODS

The authors provided the molecular data for Babesia spp. and Theileria spp. and analyzed the obtained sequences of the 18S rRNA gene, Tams1 gene and MPSP gene by using the ClustalW program in MEGA version 6.06 software and BLASTn tool of NCBI GenBank database.

RESULTS

The total infection rates were detected by nPCR with 1.8% for T. orientalis, 3% for T. sinensis, 0.6% for T. annulata, 1.8% for B. motasi and 0.6% for B. bigemina.

CONCLUSIONS

To the best of our knowledge, this is the first report investigating T. sinensis from cattle by PCR in Wuwei City. In particular, ovine B. motasi has been for the first time detected in cattle in our study and its impact is worth discussing to figure out the potential reasons.

Detection of novel piroplasmid species and Babesia microti and Theileria orientalis genotypes in hard ticks from Tengchong County, Southwest China

To reveal the genetic diversity of Babesia microti and Theileria orientalis in Southwest China, we conducted a molecular survey of piroplasms in hard ticks in a China-Myanmar border county. Host infesting and questing ticks were collected from Tengchong County in 2013 and 2014. Piroplasm infection in ticks was detected by PCR, and then, phylogenetic analysis was conducted to study the genetic diversity of the pathogens identified in ticks. All in all, six piroplasm species comprising of B. microti; B. orientalis; a novel Babesia species designated Babesia sp. Tengchong, China; T. orientalis; T. luwenshuni; and an as yet undescribed piroplasmid species referred to as Piroplasmid sp. Tengchong, China, have been identified after screening goat- and cattle-attached ticks. In addition, B. bigemina has been identified by screening questing ticks. Phylogenetic analysis based on the 18S rRNA and partial β-tubulin gene revealed two novel potentially zoonotic genotypes designated B. microti Tengchong-Type A and B. The T. orientalis genotypes identified in the present study represent the seven known genotypes 1-5, 7, and N3 as revealed by phylogenetic analysis of 18S rRNA and MPSP genes. Importantly, an additional genotype designated N4 has also been identified in this study, which brings the number of recognized T. orientalis genotypes to a total of twelve. Thus, besides the two novel species, Babesia sp. Tengchong, China, closely related to Babesia species isolated from yak and Piroplasmid sp. Tengchong, China, our study demonstrates that additional novel B. microti and T. orientalis genotypes exist in Southwest China.

High resolution melting analysis of the 18S rRNA gene for the rapid diagnosis of bovine babesiosis

Background

Bovine babesiosis is caused by protozoan parasites of the genus Babesia and presents a wide spectrum of clinical manifestations. Disease severity depends on the type of Babesia species infection. Generally, B. bovis and B. bigemina are considered as the causative agents of bovine babesiosis; in addition, Babesia ovata and B. major are a group of benign bovine piroplasms. Therefore, species identification is important for diagnosis, epidemiological investigations and follow-up management.

Methods

Real-time PCR combined with high resolution melting (RT-PCR-HRM) analysis was used to detect and discriminate four Babesia species infective to cattle, including Babesia bovis, B. bigemina, B. major and B. ovata. The melting profiles and melting temperatures (Tm) of the amplicon targeting 18S rRNA revealed differences that can discriminate the four Babesia spp. Sensitivity and specificity of the analytical method were evaluated using 50 blood samples collected from experimentally infected cattle and 240 blood samples from areas where bovine babesiosis is an issue.

Results

RT-PCR-HRM analysis allowed to detect and discriminate four Babesia spp. (B. bovis, B. bigemina, B. major and B. ovata), which were responsible for bovine babesiosis in China. The protocol was validated with DNA samples from experimentally infected cattle and field infection in cattle.

Conclusions

Our results indicate that RT-PCR-HRM is a fast and robust tool for the simultaneous detection and discrimination of four Babesia species that are responsible for bovine babesiosis in China. This approach is applicable for both field and experimental samples, thus it could be useful in epidemiological investigations and diagnoses of bovine babesiosis.

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.

Genetic diversity of Theileria orientalis from cattle in Turkey

Theileria orientalis is usually a benign parasite but some genotypes cause infection and economic losses to the cattle industry. This study was carried out to determine T. orientalis genotypes in cattle. T. orientalis positive 63 sample were analyzed by amplifying the MPSP gene region by PCR. As a result of the SSCP analysis, samples with different band profiles were sent to the sequence analysis and genotypes were determined. T. orientalis genotype-specific PCR was performed to determine the mix genotypes. Type 1 (chitose), type 3 and type 1-type 3 mix were found positive 11.1%, 46%, and 17.5% respectively. In addition, phylogenetic analysis was performed to separate the chitose genotypes, and two samples were found in chitose A, one sample was found in chitose B. Although chitose A genotype is suggested to be more pathogenic than chitose B, but there is little evidence for this. As a result of this study, we showed the presence of pathogenic genotype T. orientalis in Turkey. Therefore, extensive epidemiological studies are required to understand the geographic distribution, different genotypes and clinical pathologies of T. orientalis.