The mRNA expression of immune-related genes in crossbred and Tharparkar cattle in response to in vitro infection with Theileria annulata

Epidemiology and molecular characterization of Theileria annulata in ticks collected from cattle in the central part of Tamil Nadu, India

Tick-borne diseases are the most common in cattle in the tropical and subtropical regions of India and lead to substantial economic losses to small and marginal farmers. This study aimed to identify the diverse species of ticks infesting cattle in the central part of Tamil Nadu, India, and to assess the prevalence of Theileria annulata infection in various species of ticks through PCR. Out of 123 cross-bred and 105 native breed cattle examined for tick infestation, 40 (18%) and 29 (12.7%) cattle were infested with Ixodid ticks, respectively. The most prevalent tick species identified was Rhipicephalus microplus (n=589), followed by Hyalomma anatolicum (n=532), Hyalomma marginatum (n=145), Haemaphysalis intermedia (n=79), and Rhipicephalus haemophysaloides (n=1) found in the study area. The prevalence and intensity of the tick infestation were found to be higher in cross-bred (71.04%) than native breed cattle (28.96%), and there was no significant difference between the studied breeds (chi-square value =24; df =20; p value =0.24) was observed. However, a significant difference in the H. anatolicum tick infestation was observed between the Cauvery Delta (14.30%) and the North-Western (20%) zones of Tamil Nadu (p<0.05). DNA fragments of 193 bp derived from 18S rRNA gene sequences of T. annulata were amplified using species-specific primers. Of these, 16 out of 37 (43.2%) and 10 out of 39 (29%) pooled samples of H. anatolicum and 4 out of 18 (22.2%) and 1 out of 5 (20%) pooled samples of H. marginatum were found positive for T. annulata from the Cauvery Delta and North-Western zones, respectively. R. microplus, H. intermedia, and R. haemaphysaloides from these regions were negative. These findings confirm that H. anatolicum (52.17%) is the predominant vector for T.annulata rather than H. marginatum (18.84%), and the PCR is a useful method of determining the infection rates in ticks collected from animals carrying low levels of T. annulata piroplasms.

Exploring haplotype block structure, runs of homozygosity, and effective population size among dairy cattle breeds of India

The present study aimed to explore haplotype structure, runs of homozygosity (ROH), effective population size and persistence of gametic phase among three indigenous dairy cattle breeds, viz., Sahiwal (n = 19), Tharparkar (n = 17), and Gir (n = 16) by using BovineHD single nucleotide polymorphism (SNP) genotyping assay. The filtered SNPs after quality control ranged from 44% in Sahiwal to 53% in Gir. The highest number of haplotype blocks was observed in Tharparkar (15,640) and the lowest in Sahiwal (8027) spanning 17.3% and 7.8% of genome, respectively. The average block length was found close to 26 kb which suggests that multiple recombination events fragmented the ancestral haplotypes into smaller sizes. Gir cattle had the largest number of runs of homozygosity (ROH) regions (1762) followed by Tharparkar (1528) and Sahiwal (1138). Without pedigree information, inbreeding coefficients estimated from ROH (F_ROH) revealed that Gir had the highest F_ROH (0.099) proposing more inbreeding rate in this population. Effective population size (N_e) decreased slowly over the last 60 generations and at 13 generations ago; N_e was estimated as 70 for all the three dairy breeds. The highest gametic phase correlation (r = 0.78) was observed for Sahiwal and Tharparkar breed pair suggesting formulation of multi-breed reference population for successful implementation of genomic selection among dairy breeds. The decline in effective population size among native Indian cattle breeds may help in formulating strategies for conservation and genetic improvement of native germplasm for future use.

Genetic Resistance of Bovines to Theileriosis

Diseases caused by ticks have a high impact on the health, welfare, and productivity of livestock species. They are also an important cause of economic losses in farms worldwide. An example of such diseases is theileriosis, which can be controlled by drugs or vaccines, although these are not fully efficient. Therefore, there is a need to develop alternative and more sustainable and efficient complementary strategies. These may involve the identification and selection of animals more resistant to the disease. Several previous studies have identified significant differences in resistance between different breeds, with resistant breeds typically identified as those native to the region where they are being studied, and susceptible as those from exotic breeds. These studies have indicated that resistance traits are intrinsically related to the modulation of the immune response to infection. This review aims to systematize the general knowledge about theileriosis, emphasize resistance to this disease as a sustainable control strategy, and identify which traits of resistance to the disease are already known in cattle.

Comparative gene expression profile in circulating PBMCs of Bos indicus and crossbred cattle to understand disease tolerance mechanism

The present investigation was performed to compare the global gene expression profile in peripheral blood mononuclear cells (PBMCs) of Bos indicus and crossbred (Bos taurus × B. indicus) cattle. Previously, several studies revealed the disease tolerance potential of B. indicus cattle but underlying genetic mechanism is still not fully explored. The PBMCs model was used for this investigation as it plays crucial role in the immune system regulation. Transcriptomic analysis revealed total 6767 significantly differentially expressed transcripts (fold change (absolute) >2.0, p < .05). In addition, 4149 transcripts were upregulated, 2618 transcripts were downregulated and fold change (absolute) of differentially expressed transcript varied from -223.32 to 213.63. Functional annotation analysis of differentially expressed genes confirmed their role in various molecular pathways viz. innate immune response, antigen processing and presentation, MHC protein complex, defense response to bacterium, regulation of immune response, positive regulation of JAK-STAT cascade, cytoskeletal protein binding, etc. Protein-protein interaction network analysis provided understanding of inter-relationship of immune genes with differentially expressed genes. In conclusion, this study could provide comprehensive information about the dysregulated genes and biological pathways in PBMCs which might be responsible for disease tolerance in B. indicus cattle.

Molecular and phylogenetic analysis of MHC class I exons 7-8 in a variety of cattle and buffalo breeds

The present study was conducted on the MHC class I (BoLA-A/BuLA-A) gene in Sahiwal, Jersey, Hariana, and Tharparkar breeds of cattle and Murrah, Mehsana, and Bhadawari breeds of buffalo to study the polymorphism. Exons 7-8 of the MHC class I gene was first characterized for polymorphism study in buffalo and the results reveal that this gene has a higher level of nucleotide changes than the cattle. Genes were investigated for polymorphisms in 285 animals of cattle and buffalo breeds. Molecular characterization of the MHC class I (BoLa-A/Bula-A) gene reveals a higher degree of polymorphism at the nucleotide level in cattle and buffalo. Results revealed this region has a higher level of polymorphisms in buffalo as campared to the cattle. Alul restriction patterns were monomorphic except for three different patterns but it was able to illustrate the differences in buffalo and cattle. SSCP analysis of exons 7-8 showed remarkable differences in cattle and buffalo. Sequence analysis revealed more closeness of Murrah breed with crossbred and indigenous cattle than Holstein Friesian. Exon 8 had more deletion and stop codon as compared to exon 7. The investigation confirmed that MHC class I BoLa-A/Bula-A exons 7-8 is highly polymorphic in buffalo as compared to cattle.

Innate Immune Response to Tick-Borne Pathogens: Cellular and Molecular Mechanisms Induced in the Hosts

Many pathogens are transmitted by tick bites, including Anaplasma spp., Ehrlichia spp., Rickettsia spp., Babesia and Theileria sensu stricto species. These pathogens cause infectious diseases both in animals and humans. Different types of immune effector mechanisms could be induced in hosts by these microorganisms, triggered either directly by pathogen-derived antigens or indirectly by molecules released by host cells binding to these antigens. The components of innate immunity, such as natural killer cells, complement proteins, macrophages, dendritic cells and tumor necrosis factor alpha, cause a rapid and intense protection for the acute phase of infectious diseases. Moreover, the onset of a pro-inflammatory state occurs upon the activation of the inflammasome, a protein scaffold with a key-role in host defense mechanism, regulating the action of caspase-1 and the maturation of interleukin-1β and IL-18 into bioactive molecules. During the infection caused by different microbial agents, very similar profiles of the human innate immune response are observed including secretion of IL-1α, IL-8, and IFN-α, and suppression of superoxide dismutase, IL-1Ra and IL-17A release. Innate immunity is activated immediately after the infection and inflammasome-mediated changes in the pro-inflammatory cytokines at systemic and intracellular levels can be detected as early as on days 2–5 after tick bite. The ongoing research field of “inflammasome biology” focuses on the interactions among molecules and cells of innate immune response that could be responsible for triggering a protective adaptive immunity. The knowledge of the innate immunity mechanisms, as well as the new targets of investigation arising by bioinformatics analysis, could lead to the development of new methods of emergency diagnosis and prevention of tick-borne infections.

An Overview of Peripheral Blood Mononuclear Cells as a Model for Immunological Research of Toxoplasma gondii and Other Apicomplexan Parasites

In biology, models are experimental systems meant to recreate aspects of diseases or human tissue with the goal of generating inferences and approximations that can contribute to the resolution of specific biological problems. Although there are many models for studying intracellular parasites, their data have produced critical contradictions, especially in immunological assays. Peripheral blood mononuclear cells (PBMCs) represent an attractive tissue source in pharmacogenomics and in molecular and immunologic studies, as these cells are easily collected from patients and can serve as sentinel tissue for monitoring physiological perturbations due to disease. However, these cells are a very sensitive model due to variables such as temperature, type of stimulus and time of collection as part of posterior processes. PBMCs have been used to study Toxoplasma gondii and other apicomplexan parasites. For instance, this model is frequently used in new therapies or vaccines that use peptides or recombinant proteins derived from the parasite. The immune response to T. gondii is highly variable, so it may be necessary to refine this cellular model. This mini review highlights the major approaches in which PBMCs are used as a model of study for T. gondii and other apicomplexan parasites. The variables related to this model have significant implications for data interpretation and conclusions related to host-parasite interaction.

Exploring the TLR and NLR signaling pathway relevant molecules induced by the Theileria annulata infection in calves

Theileria annulata is the pathogen of bovine tropical theileriosis. It is extremely harmful to the cattle industry, with huge economic losses. The toll-like receptor (TLR) and NOD-like receptor (NLR) signaling pathways are crucial for resistance to infection of the protozoa, such as Plasmodium falciparum, Toxoplasma gondii, and Trypanosoma cruzi. However, the role of these immune-related pathways is unclear during T. annulata infection. In the present study, peripheral blood mononuclear cells and serum were separated from blood samples of calves infected with homogenized tick supernatants carrying T. annulata sporozoites at 12 h, 24 h, 36 h, 48 h, 72 h, 96 h, 120 h, 144 h and 168 h postinoculation. The Custom RT² Profiler PCR Array was used to explore the mRNA levels of 42 TLR and NLR signaling pathway relevant genes. The TLR1, TLR6, TLR10, NLRP1, and MyD88 genes and their downstream signaling molecules significantly differed after the T. annulata infection in comparison with that of preinfection from 72 h to 168 h postinoculation. The serum concentrations of IL-6, IL-1β, and TNFα were significantly increased at 96 h and 168 h postinfection. These findings provided novel information to help determine the mechanisms of TLR and NLR signaling pathway involvement in protection against T. annulata infection.

A rare case of Theileria annulata induced corneal opacity in a calf

A 10 months old male cross-bred calf was presented in OPD Medicine, Referral Veterinary Polyclinic, ICAR-Indian Veterinary Research Institute, Izatnagar with the history of anorexia, impaired vision, heavy tick infestation and diarrhoea for the last 1 week. The clinical examination revealed enlarged pre-scapular lymph nodes, prominent cloudiness in eyes and exophthalmos. The presence of Koch blue bodies in biopsied lymph nodes and a PCR assay confirmed it to be bovine tropical theileriosis associated with unique corneal opacity. Treatment with buparvaquone at a dose of 2.5 mg/kg i.m. two doses 48 h apart was successful and typical ocular manifestations completely subsided after 2 weeks of therapy.

Molecular markers for resistance against infectious diseases of economic importance

Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne's disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA--DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically possible to achieve, and is permanent. Progress could be enhanced through introgression of resistance genes to breeds with low resistance. The quest for knowledge of the genetic basis for infectious diseases in indigenous livestock is strongly warranted.

Studies on alterations of clinical and hemato-biochemical parameters before and after treatment in calves naturally infected with theileriosis

Aim:

The aim was to determine hemato-biochemical alterations and to determine the better treatment of theileriosis in naturally infected calves.

Materials and Methods:

A total of 74 Holstein crossbred calves below 6 months of age, of either sex were included for present investigation in Bikaner. Based on the clinical examinations and laboratory results, 20 calves included for hemato-biochemical studies (before and after treatment) and divided into two groups (having 10 calves each).

Results:

The clinical examination of these calves revealed weakness, ticks infestations, high fever above 104°F, pronounced swelling of prescapular, prefemoral, parotid lymph nodes, loss of elasticity of skin, anemia, lacrimal discharges, pulpy cornea, tachycardia, and dyspnea. There was highly significant decrease (p<0.01) in hemoglobin, total erythrocyte count, packed cell volume and total leukocyte count, serum glucose, total protein, globulin and albumin level and highly significant increase in aspartate aminotransferase and alanine aminotransferase level as compared to healthy control animals in Group I and II. The animals of Group II treated with buparvaquone along with single blood transfusion shows better recovery then animals of Group I treated with bupavaqone and hematinic.

Conclusions:

Significant changes were found in hemato-biochemical parameters in theileria affected calves before treatment as compare to healthy control calves. Significant improvement was observed in hemato-biochemical parameters in buparvaquone and single blood transfusion treated calves as compare to another group, so it is concluded that buparvaquone and single blood transfusion is better combination for treatment of theileriosis.