Coexistence of Multiple Theileria annulata Genotypes Circulating in Neonatal Calves in Semi-arid India

Comparative diagnostic performance of recombinant Tams1 protein based dot-ELISA in detecting tropical theileriosis in naturally infected cattle

This study is the first to conduct a sero-surveillance of Bovine Tropical Theileriosis (BTT) caused by the protozoan parasite Theileria annulata (T. annulata) using a recombinant Tams1 protein-based dot-ELISA in cattle, and to compare its efficacy with plate-ELISA, single PCR, nested PCR, and blood microscopy. The goal was to identify the most effective method for the early and accurate detection of theileriosis, which significantly impacts livestock through reduced milk yield and increased mortality. A total of 101 field blood samples were examined using blood smear analysis, single PCR, nested PCR, and dot-ELISA. The recombinant Tams1 protein was successfully cloned and expressed using a pET-30b (+) expression vector in a prokaryotic system. The protein was purified with Ni-NTA chromatography, confirmed for immunoreactivity with T. annulata positive serum via Western blot analysis, and used to optimize both dot-ELISA and plate-ELISA. Both dot-ELISA and plate-ELISA using recombinant Tams1 protein exhibited comparable diagnostic performance, with a kappa value of 0.826 and similar analytical productivity (P = 0.6165). Dot-ELISA revealed a BTT seroprevalence of 58.4% in the cattle population, demonstrating good sensitivity (93.33%) and specificity (90%). The diagnostic performance of dot-ELISA was found to be superior to other molecular techniques, including microscopy, single PCR, and nested PCR. Dot-ELISA is also a sustainable solution in comparison to other laboratory diagnostic techniques with benefits of early diagnosis, reduced waste generation, resource efficiency, cost-effective point of care disease surveillance. With its minimal antigen requirement, Tams1 molecule based dot-ELISA is recommended as an effective tool for epidemiological studies and field surveys of BTT.

The interplay of cytokines in bovine tropical theileriosis: a mini review

Studying cytokine profiling in Theleria annulata infection enhances our understanding of how the immune response unfolds, the intricate interactions between the host and the parasite, the strategies employed by the parasite to evade the immune system, and potential avenues for developing treatments. The generation of pro-inflammatory cytokines plays a pivotal role in the immune response against T. annulata infection. Elevated concentrations of these cytokines potentially contribute to the manifestation of clinical symptoms associated with the disease, such as fever, anemia, exophthalmia, and weight loss. The production of anti-inflammatory cytokines potentially serves as a regulatory mechanism for the immune response, preventing the development of severe disease. Nevertheless, in animals afflicted by T. annulata infection, there is often a notable decrease in the levels of these cytokines, suggesting that they may not be as effective in mitigating the disease as they are in uninfected animals. This knowledge can be harnessed to develop improved diagnostic methods, treatments, and vaccines for tropical theileriosis. The objective of this current mini review is to achieve the same goal by consolidating the available knowledge of cytokine interactions in Bovine Tropical Theileriosis (BTT).

Molecular characterization and prevalence of bovine hemoprotozoan and rickettsial organism from Bhubaneswar, Eastern India

The blood parasites adversely affect the bovine population and are one of the major hindrances to productivity and health of livestock, globally. This study aimed to study the prevalence of some bovine hemoparasites, their molecular characterization, and associated risk factors in and around Bhubaneswar, a place in Eastern India. Microscopy (Giemsa stained thin blood smear) and polymerase chain reaction (PCR)-based prevalence studies were undertaken for a total of 106bovine blood samples belonging to different breed, age, and sex presented to Veterinary Clinical Complex. DNA was extracted by conventional method and primer targeting msp5 gene (382 bp) for Anaplasma marginale, Tams1 gene (572 bp) for Theileria annulata and VSG RoTat 1.2 gene (110 bp) for Trypanosoma evansi, were used. Sequencing and phylogenetic analysis were also carried out for representative PCR products. The risk factors were correlated with prevalence by logistic regression analysis. Blood smear examination revealed a prevalence an overall of 48.11% (51/106) out of which the prevalence of T. annulata, A. marginale and T. evansi, and concurrent infection were reported to be 26.42%, 10.38%, 3.77%, and 7.55% respectively. All the samples found positive in microscopy were also found positive in PCR. PCR assay revealed an overall prevalence of 73.58% (T. annulata: 37.74%, A. marginale:17.92%, T. evansi: 5.66% and concurrent infection:12.26%). A higher prevalence was observed in the age group of 2-4 years (37.74%), females (61.32%) and cross-bred Jersey (50%). Representative PCR products were sequenced and assigned by GenBank (OL550058: A. marginale; OL604429: T. annulata and OL550059: T. evansi). There is a paucity of disease mapping of these parasites in most parts of the country. The study is probably the first report of molecular characterization of T. evansi and A. marginale from the region which gives some information of possible genetic diversity of the isolates circulating in the region. Future research should include large-scale epidemiological surveys as well as concurrent diagnosis of these hemoparasites for better treatment and control strategies.

Comprehensive genetic diversity and molecular evolutionary analysis of Theileria annulata isolates based on TAMS 1 gene

Molecular epidemiological studies related to the phylogenetic characterization of Theileria annulata are important in delineating the evolutionary history of the parasite. In the current study, the Theileria annulata (T. annulata) merozoite surface antigen 1 (TAMS 1) gene from 14 bovine isolates of T. annulata originating from semi-arid zone of northern India were amplified and sequenced. TAMS 1 gene sequences (n= 337) reported from 16 countries were subsequently analyzed for haplotype network along with genetic diversity. A total of five haplotypes out of the 14 sequenced isolates and 92 haplotypes out of 337 worldwide sequences are documented in this study. Phylogenetic and molecular evolutionary analyses based on TAMS 1 gene sequences showed that T. annulata is dissipated across different countries and numerous strains are closely linked, even though they belong to different geographical locations. The nucleotide homology between 14 isolates from northern India varied between 91.3 and 100%, whereas it was between 31.5 and 100% when sequences across the globe were compared. Haplotype 14 was recognized as most widely distributed haplotype, with 46 isolates circulating in 10 countries. Globally, negligible genetic distance (FST˂0.15) and very high gene flow (Nm˃1) was found in the five populations of the world (South Asia, East Asia, West Asia, Europe and Africa), supporting the absence of clearly defined subgroups in the phylogenetic analysis. Significant negative values of neutrality tests; Tajima's D (D) and Fu and Li's F (F) provided evidence for recent population expansion through positive selection of advantageous variations.

An endpoint visualization loop-mediated isothermal amplification (LAMP) for detecting bubaline theileriosis

Background

Tropical theileriosis is a significant disease affecting the health and production levels of buffaloes in India. It is caused by an apicomplexan—Theileria annulata. The timely and accurate detection of infection is vital for implementing a mass vaccination or control programme in a given area under outbreak. Most of the literature concerned with diagnosis of theileriosis revolves around cattle, and practically, there are very limited assays available for detecting bubaline theileriosis. Loop-mediated isothermal amplification (LAMP) assay certainly amplifies the targeted deoxyribosenucleic acid (DNA) with a comparatively higher efficacy, rapidity and sensitivity. Alongside, minimal use of sophisticated instruments in performing LAMP assay is certainly an add on. The present study describes the application of LAMP assay in diagnosing tropical theileriosis in buffaloes alongside, its comparison with polymerase chain reaction (PCR) and blood microscopical examination.

Results

No cross-reaction was seen with DNA of other haemoprotozoan. LAMP was compared with blood microscopy and PCR. LAMP detected infection in 27 out of 100 buffaloes, while blood microscopy and PCR detected disease in 16 and 24 buffaloes, respectively.

Conclusion

The sensitivity, specificity and kappa value prediction of LAMP were found to be much higher than the PCR and blood microscopy. The present communication reports the first use of LAMP in detecting theileriosis in buffaloes in the world.

Successful treatment of severe form of bovine tropical theileriosis in dairy cattle and genotyping of Theileria annulata isolates of Tamil Nadu, India

Bovine tropical theileriosis (BTT) is a tick-borne protozoan disease of cattle and responsible for major economic losses to the dairy farmers in India. This report describes diagnosis, genotyping and successful treatment of heavy infection of Theileria annulata in an organized dairy farm at Kattupakkam, Chennai. Four cross bred cows of 2 to 5 years of age showed clinical signs i.e., anorexia, salivation and panting. Clinical examination revealed pyrexia (40.0 °C to 40.1 °C), pale mucus membranes, enlarged prescapular lymph nodes and haemoglobinuria. The peripheral blood smear examination of infected cows revealed presence of piroplasm within the RBCs indicating high parasitemia. Haematology results suggested that decreased levels of Hb, RBC, WBC and PCV in the infected cows when compared with normal reference values. There were increased serum ALT and AST values and reduced serum total protein, albumin, calcium and phosphorous values in the infected cows. Semi-nested PCR using T. annulata specific oligonucleotide primers amplified 199 bp of the partial T. annulata 18S rRNA gene. Presence of four satellite markers TS6, TS8, TS9, and TS12 in the Theileria annulata isolates 1 and 2 indicating that the isolates were the same haplotype and suggested the infection in the farm was due to a single haplotype of T. annulata parasite. Based on the clinical signs, microscopic examination of blood smear and molecular diagnosis, the condition was diagnosed as tropical theileriosis. Infected cows were successfully treated with a single deep intramuscular injection of buparvaquone (Zubion®, INTAS pharmaceuticals LTD, Ahmedabad, India) along with supportive medication.

Epidemiology, haematology and molecular characterization of haemoprotozoon and rickettsial organisms causing infections in cattle of Jammu region, North India

BACKGROUND

The present study was aimed at establishing the prevalence, epidemiology and molecular characterization of major haemoprotozoons (Babesia and Theileria) and rickettsia (Anaplasma) of cattle in Jammu region (North India) using microscopy and Polymerase Chain Reaction (PCR). Hematology, microscopy and PCR based prevalence studies were undertaken with 278 whole blood samples from cattle. Molecular prevalence studies were followed by genetic characterization of the isolates of Babesia, Anaplasma and Theileria spp. based on 18S rRNA, 16S rRNA and Tams1 gene, respectively. The data related to metrology and epidemiological variables like temperature, rainfall, season, age and type of livestock rearing was analyzed and correlated with occurrence of disease by statistical methods.

RESULTS

The prevalence based on microscopy was 12.9% (36/278) whereas PCR recorded 30.22% (84/278) animals positive for haemoparasitic infections. All the samples found positive by microscopy were also recorded positive by PCR. Thus the study revealed prevalence of Babesia bigemina, Anaplasma marginale and Theileria annulata to be 9.7, 16.5 and 0.7% respectively. The metrological and epidemiological variables made inroads for the propagation of vector ticks and occurrence of infection. Haematological alterations predominantly related to decrease in haemoglobin, red blood cell count and packed cell volume were evident in diseased animals and collaterally affected the productivity. Further the genetic characterization of Babesia bigemina. (MN566925.1, MN567603, MN566924.1), Anaplasma marginale. (MH733242.1, MN567602.1) and Theileria annulata (MT113479) provided a representative data of the isolates circulating in the region and their proximity with available sequences across the world.

CONCLUSIONS

Despite holding much significance to the animal sector, comprehensive disease mapping has yet not been undertaken in several parts of India. The present study provides a blue print of disease mapping, epidemiological correlations and genomic diversity of Babesia bigemina, Anaplasma marginale and Theileria annulata circulating in the region.

Rapid diagnosis of Theileria annulata by colorimetric loop-mediated isothermal amplification (LAMP) assay

Theileria annulata the causative agent of bovine tropical theileriosis (BTT) is globally distributed. Rapid and accurate detection of the parasite is essential for the implementation and evaluation of mass drug administration and planned vaccination programs for controlling BTT. Loop mediated isothermal amplification (LAMP) amplifies targeted nucleic acid with a high efficacy, sensitivity and rapidity under isothermal conditions. In the present study, the internal transcriber space (ITS) gene of T. annulata was targeted for the development of a LAMP assay using pH-sensitive dye (phenol red) for enhanced visual detection of amplification. This method employed a set of specially designed four primers that recognized six distinct regions on the targeted gene. No amplification was detected with the DNA of other tested haemoprotozoans. Positive LAMP products were identified by a colour change from pink to yellow, and then rechecked by specific ladder pattern upon agarose gel electrophoresis. LAMP was able to detect infection in 63 out of 85 animals compared with blood microscopy, simple PCR and nested PCR which detected infection in 40, 49 and 64 animals, respectively. No difference in detection was seen in the colorimetric assay and the classical UV based LAMP assay.