Seroprevalence of bovine theileriosis in northern China

Hemopathogens in naturally infected bovine fetuses in Brazil

The transplacental transmission of parasites and hemoparasites is crucial for understanding the epidemiology of diseases. This study aimed to assess the prevalence of hemopathogens in bovine fetuses at various gestational periods. Samples were obtained from a slaughterhouse in the state of Minas Gerais, Brazil, and a total of 236 fetuses were collected. DNA extracted from blood samples (145) and organ samples (a pool of brain and spleen) (236) underwent a nested PCR (nPCR) assay to detect Babesia spp., Theileria spp., Trypanosoma vivax, Anaplasma marginale, Anaplasma bovis, Anaplasma phagocytophilum, Ehrlichia minasensis, and hemotropic Mycoplasma spp. Additionally, serological analysis of 145 plasma samples was conducted using the indirect fluorescent antibody test-IFAT to detect IgG against Babesia bovis, Babesia bigemina, A. marginale, and Trypanosoma vivax. The observed prevalence of transplacental transmission was 19.3 %, 6.2 %, 42.7 % and 2.7 %, for A. marginale, B. bigemina, 'Candidatus M. haemobos', and Mycoplasma wenyonii, respectively. The prevalence of A. marginale by gestational trimester was 16 % (13/81) in the second trimester and 23 % (14/60) in the third trimester, with no positive samples in the first trimester. Regarding the species B. bovis and B. bigemina, all evaluated animals tested negative by nPCR, and no serological evidence for B. bovis was found by the IFAT. Babesia bigemina demonstrated an overall seroprevalence of 6.2 % (9/145), with 4.8 % (7/145) in the last trimester and 1.3 % (2/145) in the second trimester of pregnancy. In total, 42.7 % (62/145) of blood samples were positive for 'Candidatus M. haemobos', with 42 % (34/81) in the middle trimester, and 43 % (26/60) in the final trimester of pregnancy. Mycoplasma wenyonni was detected in 2.7 % (4/145) blood samples, all in coinfection with 'C. M. haemobos'. The prevalence by pregnancy trimester was 25 % (1/4) in the first trimester; 1.2 % (1/81) in the second trimester and 3.3 % (2/60) in the third trimester of pregnancy. Hemopathogen DNA was detected in fetus blood samples but not the brain or spleen samples. All the samples were negative for T. vivax, Theileria spp., Anaplasma spp. and Ehrlichia spp. Overall, in this study, approximately 70 % of fetuses were positive for one or more of the studied parasites. No significant associations were observed between pairs of pathogens, except 'C. M. haemobos' and A. marginale.

Establishment and application of TaqMan real-time PCR method for detection of Theileria annulata resistant to buparvaquone

Tropical theileriosis is a tick-borne disease that caused by Theileria annulata, and leads to substantial economic impact in endemic area. Distinguishes to other piroplasms, Theileria is the only eukaryotic parasite could transform mammalian leukocytes. At present, buparvaquone is the most effective drug used for treatment of Theileria infection. However, frequently reported of failure treatment with buparvaquone for some T. annulata isolates. Mutation of TaPIN1 was reported to be the direct reason for failure of buparvaquone treatment. Through in vitro culture, a T. annulata isolate with a TaPIN1 mutation that is similar to the reported strain was recently identified in China. In order to understand the distribution of Theileria with mutation of TaPIN1 in China, here we developed a TaqMan probe-based real-time PCR technology to detect the mutated TaPIN1 gene. The specificity, sensitivity and reproducibility of the established TaqMan Real-time PCR method were evaluated, and field cattle blood samples collected from Xinjiang Uyghur Autonomous Region were used to test its application. Among 1683 samples, 335 samples were confirmed positive for T. annulata by traditional PCR method and 34 samples were positive for buparvaquone-resistant. The TaPIN1 gene of those 34 samples was sequenced and analyzed with the published gene sequences from NCBI database. The results showed that the sequence obtained from the present study has good consistency with those published sequences. In conclusion, the TaqMan probe-based real-time PCR targeting T. annulata mutated TaPIN1 gene was successfully established and can be used to detect clinical samples to investigation of buparvaquone-resistant parasites in Xinjiang region quickly and accurately, which will be useful for guiding clinical medicine application.

Tick symbiosis

As obligate blood-feeders, ticks serve as vectors for a variety of pathogens that pose threats on both human and livestock health. The microbiota that ticks harbor play important roles in influencing tick nutrition, development, reproduction, and vector. These microbes also affect the capacity of ticks to transmit pathogens (vector competence). Therefore, comprehending the functions of tick microbiota will help in developing novel and effective tick control strategies. Here, we summarize the effects of main tick symbiotic bacteria on tick physiology and vector competency.

Multiplex PCR for rapid differential diagnosis of co-prevalent species of Theileria (Theileria annulata and Theileria orientalis) in cattle

Theileriosis is a tick-borne disease that causes enormous losses in the dairy industry. There are several species of Theileria that can infect bovines. Generally, more than one species are prevalent in any geographical area; thus, chances of co-infections are high. Differentiation of these species may not be possible by microscopic examination or serological tests. Therefore, in this study, a multiplex PCR assay was standardized and evaluated for rapid and simultaneous differential detection of two species of Theileria viz., Theileria annulata and Theileria orientalis. Species-specific primers were designed to target the merozoite piroplasm surface antigen gene (TAMS1) of T. annulata and the major piroplasm surface protein gene of T. orientalis, yielding specific amplicon of 229 bp and 466 bp, respectively. The sensitivity of multiplex PCR was 10² and 10³ copies for T. annulata and T. orientalis, respectively. The simplex and multiplex PCRs were specific and showed no cross-reactivity with other hemoprotozoa for either primer. For comparative evaluation, blood samples from 216 cattle were tested by simplex and multiplex PCR for both species. Using multiplex PCR, 131 animals were found infected for theileriosis, of which 112 were infected with T. annulata, five were infected with T. orientalis, and 14 had mixed infections. This is the first report of T. orientalis from Haryana, India. Representative sequences of T. annulata (ON248941) and T. orientalis (ON248942) were submitted in GenBank. The standardized multiplex PCR assay used in this study was specific, sensitive, for the screening of field samples.

Seroprevalence and risk factors of tropical theileriosis in smallholder asymptomatic large ruminants in Egypt

Knowledge of the prevalence and epidemiological determinants of tropical theileriosis in large ruminants, particularly in the asymptomatic carrier, is crucial for designing and implementing effective host-specific control measures. This study aimed to estimate the seroprevalence of tropical theileriosis in asymptomatic cattle and water buffaloes and identify the potential risk factors of theileriosis in large ruminants raised under smallholder-production system in Egypt. A cross-sectional study was conducted in five districts of the Sharkia governorate from March 2019 to February 2020. In total, 350 serum samples were collected from cattle and water buffaloes under smallholder-production system and tested for Theileria annulata antibodies using the indirect antibody fluorescence test (IFAT). Data on species, host characteristics, presence of ticks, season, and districts were collected at sampling using a questionnaire. A multivariable mixed-effects logistic regression model was built to determine the potential risk factors associated with T. annulate seropositivity of the animals. The overall apparent seroprevalence of T. annulata in 350 tested animals was 70%. In the univariable analyses, cattle compared to buffaloes, younger animals compared to older ones, animals with ticks on their bodies, and warmer seasons were all associated with a higher likelihood of seropositive results in the study population while sex of the animals was not associated with seropositivity. The final multivariable model showed that animals with ticks on their bodies had 3.5× higher odds of seropositivity than those with no ticks (P < 0.001), and warmer seasons were associated with the higher odds of infection compared to winter (P = 0.003). The high seroprevalence of tropical theileriosis in the study region indicates that the disease is endemic among smallholders of large ruminants. The identified risk factors of T. annulata-seropositivity in asymptomatic carrier animals provides evidence-based guidance for adopting effective intervention measures.

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.

Cross-priming amplification targeting the 18S rRNA gene for the rapid diagnosis of Babesia bovis infection

Babesia bovis is a known causative agent of bovine babesiosis and is widely distributed across China. Rapid detection and accurate identification of B. bovis is essential for follow-up management and epidemiological investigations. In this study, a cross-priming amplification combined with vertical flow (CPA-VF) assay was developed. The detection limit of the CPA-VF assay targeting the 18S rRNA gene was 320 fg per reaction at 61 °C for 60 min. No cross-reactions were observed with other piroplasms infective to cattle. Furthermore, 36 blood samples from experimentally-infected animals were accurately assessed using the CPA-VF assay. The performance of the CPA-VF assay was compared with the results of conventional PCR for 219 blood samples from the field. Our results demonstrate that the CPA-VF assay is a practical and effective diagnostic tool for bovine babesiosis caused by B. bovis infection.

Genomic Profiling for Piroplasms in Feeding Ixodid Ticks in the Eastern Cape, South Africa

Importation of tick-infected animals and the uncontrollable migration of birds and wild animals across borders can lead to geographical expansion and redistribution of ticks and pathogen vectors, thus leading to the emergence and re-emergence of tick-borne diseases in humans and animals. Comparatively, little is known about the occurrence of piroplasms in ixodid ticks in the Eastern Cape, South Africa, thus necessitating this study, which is aimed at detecting piroplasms (Theileria and Babesia) from feeding tick samples collected from cattle, sheep, and goats in selected sites in the Eastern Cape, South Africa. A total of 1200 feeding ixodid ticks collected from farm animals at selected homesteads were first subjected to molecular identification using mitochondrial 12S ribosomal RNA (rRNA) gene by PCR and were further tested for the presence of piroplasms through amplification of the 18S rRNA gene via nested-PCR followed by sequencing of the PCR products. The results indicated that 853 (71.1%) corresponded to the genus Rhipicephalus, 335 (27.9%) corresponded to genus Amblyomma, and 12 (1%) corresponded to genus Haemaphysalis. Amblyomma hebraeum and Rhipicephalus appendiculatus were the most common identified ticks from this study. The 18S rRNA nested-PCR revealed that 44 (3.7%) samples were confirmed positive for Theileria. A homology search for the generated sequences revealed a high percentage identity of 98–98.9% similarity to T. buffeli, T. orientalis, and T. sergenti in the GenBank. Based on the results obtained herein, we conclude that there is a big diversity of Theileria species; therefore, we suggest that this research should cover more geographical areas in order to reveal the true prevalence of this pathogen in the studied area because this will be a great step in the possible prevention of an outbreak that could have devastating effects on livestock production and human health in both the studied areas and South Africa at large.

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.

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

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

Common occurrence of Theileria annulata and the first report of T. ovis in dairy cattle from Southern Xinjiang, China

Bovine theileriosis is a common tick-born disease infected by Theileria spp. causing loss of beef and dairy cattle worldwide, therefore, the aim of this study was to determine the prevalence and genetic diversity of Theileria spp. in Southern Xinjiang Uyghur Autonomous Region, China. We screened 493 dairy cattle blood samples from Southern Xinjiang to detect Theileria spp. by PCR. The overall prevalence of Theileria spp. was 23.5% (116/493). The most frequent Theileria sp. was Theileria annulata 22.5% (111/493), followed by T. orientalis (0.6%, 3/493) and T. ovis (0.2%, 1/493). Additionally, one sample was co-infected with T. annulata and T. orientalis. Phylogenetic analysis showed that the 11 T. annulata Tams1 sequences grouped into three sequence clusters that belonged to group 2 (Asia group) and shared 96.4% to 99.9% identity with to each other. Furthermore, our results revealed the presence of several T. orientalis MPSP genotypes (types 1, 2, and 5) in this region. In this study, T. annulata was found to be the most prevalent Theileria species in dairy cattle from Southern Xinjiang. Theileria ovis was detected in one DNA sample of a free-grazing dairy cow from China for the first time.