Resistance and susceptibility to a protozoan parasite of cattle—Gene expression differences in macrophages from different breeds of cattle

Characterisation of field tropical Theileriosis and associated risk factors in two bioclimatic areas of Algeria

Tropical theileriosis (TT) is a tick-borne disease caused by Theileria annulata and commonly infects cattle in tropical and subtropical regions, including Algeria. It is a significant obstacle to cattle breeding programs established to improve production in Algeria. The present investigation aimed to estimate the current molecular prevalence, risk factors, and genetic characterisation of T. annulata in two bioclimatic areas of Algeria. In a cross-sectional study, 679 blood samples (629 from healthy cattle selected on farms and 50 from diseased cattle identified by veterinarians) were collected from the humid (n = 307+50) and semi-arid (n = 322) areas and screened by blood smear examination followed by polymerase chain reaction targeting cytochrome oxidase subunit 3 (cox III) mitochondrial and the 18S ribosomal RNA (18S rRNA) genes for Theileria spp. Seventy-six positive samples (56 clinically healthy and 20 with clinical signs) for Theileria spp. were confirmed to be T. annulata by the merozoïtes surface antigen-1 (Tams1) gene showing a rate of 8.9 % in clinically healthy and 40.0 % in suspected cattle. Among the 307 bloods samples collected from healthy cattle in the humid area, 25 cattle (8.1 %) were positive for T. annulata. Of the 322 healthy cattle from the semi-arid site, 31 (9.6 %) were carriers of T. annulata DNA. In subclinical population, demographic and environmental parameters analysis indicated that T. annulata infection was higher in adult crossbred cattle raised in the intensive and semi-intensive system (P<0.001). The multiple logistic regression analysis showed that age, breed, farming system, and bioclimatic area are potential risk factors for T. annulata infection in cattle (P<0.05). Multiple alignments of cox III sequences of T. annulata showed high heterogeneity with 25 polymorphic sites (nucleotide diversity π = 0.02402), resulting in two haplotypes with a low genetic diversity index (Hd) of 0.533. The 18S rRNA sequence alignment revealed only one T. annulata genotype with 100 % identity to the strains isolated from cattle and ticks in Mediterranean and Asian countries. Our preliminary results will serve as a basis for further studies on the genetic diversity and molecular epidemiology of T. annulata.

A Genome-Wide Association Study for Resistance to Tropical Theileriosis in Two Bovine Portuguese Autochthonous Breeds

The control of Tropical Theileriosis, a tick-borne disease with a strong impact on cattle breeding, can be facilitated using marker-assisted selection in breeding programs. Genome-wide association studies (GWAS) using high-density arrays are extremely important for the ongoing process of identifying genomic variants associated with resistance to Theileria annulata infection. In this work, single-nucleotide polymorphisms (SNPs) were analyzed in the Portuguese autochthonous cattle breeds Alentejana and Mertolenga. In total, 24 SNPs suggestive of significance (p ≤ 10-4) were identified for Alentejana cattle and 20 SNPs were identified for Mertolenga cattle. The genomic regions around these SNPs were further investigated for annotated genes and quantitative trait loci (QTLs) previously described by other authors. Regarding the Alentejana breed, the MAP3K1, CMTM7, SSFA2, and ATG13 genes are located near suggestive SNPs and appear as candidate genes for resistance to Tropical Theileriosis, considering its action in the immune response and resistance to other diseases. On the other hand, in the Mertolenga breed, the UOX gene is also a candidate gene due to its apparent link to the pathogenesis of the disease. These results may represent a first step toward the possibility of including genetic markers for resistance to Tropical Theileriosis in current breed selection programs.

Investigation of haematological, inflammatory and immunological response in naturally infected cattle with Theileria annulata

In this study, we aimed to investigate haematological, pro-inflammatory, inflammatory, anti-inflammatory and immunological responses in naturally Theileria annulata-infected cattle. The study material consisted of 25 Simmental cattle, 2-4 years of age, one of which was a control group consisting of healthy animals (Control group, n = 10), and the other was a Theileria group that include animals positive for Theileria annulata (Theileria group, n = 15). Haematological analysis (red blood cell [RBC], haemoglobin [HGB], haematocrit [HCT]), pro-inflammatory (tumour necrosis factor-α [TNF-α], nuclear factor kappa B [NF-ĸB] and interleukin-1 beta, [IL-1β]), inflammatory (neutrophil-lymphocyte ratio [NLR]), anti-inflammatory (interleukin-10 [IL-10]) and antimicrobial peptide (CAMP) analyses were performed by using ELISA kit from blood samples. It was found that the rectal temperature of the Theileria group was found to be significantly higher (p < .001) than that of the control group. Haematological and biochemical analysis revealed that the RBC and HGB count and HCT percentage decreased (p < .001), while NF-ĸB (p < .001), TNF-α (p = .002), IL-1β (p < .001), IL-10 (p = .012), NLR (p < .001) and CAMP (p = .037) levels increased in Theileria group compared to the control group. There was a strong correlation between NF-ĸB and TNF-α, NF-ĸB and IL-10, NLR and IL-1β, NF-ĸB and CAMP, TNF-α and CAMP and IL-10 and CAMP. As a result of this study, it was revealed that a pro-inflammatory and immunological response also occurs along with the anti-inflammatory response in the inflammatory process.

Cancerogenic parasites in veterinary medicine: a narrative literature review

Parasite infection is one of the many environmental factors that can significantly contribute to carcinogenesis and is already known to be associated with a variety of malignancies in both human and veterinary medicine. However, the actual number of cancerogenic parasites and their relationship to tumor development is far from being fully understood, especially in veterinary medicine. Thus, the aim of this review is to investigate parasite-related cancers in domestic and wild animals and their burden in veterinary oncology. Spontaneous neoplasia with ascertained or putative parasite etiology in domestic and wild animals will be reviewed, and the multifarious mechanisms of protozoan and metazoan cancer induction will be discussed.

Prevalence and Risk Factors Associated with Theileria annulata Infection in Two Bovine Portuguese Autochthonous Breeds

Tropical Bovine Theileriosis is an important tick-borne disease. This study aims to assess the occurrence of Theileria annulata infection in two indigenous Portuguese cattle breeds. A total of 843 blood samples collected from animals of Alentejana (n = 420) and Mertolenga (n = 423) breeds were analyzed. The detection of Theileria annulata was determined by amplification of a fragment of the merozoite-pyroplasm surface antigen gene with 319 base pairs (bp). The prevalence found (10.8%) is lower than that reported in previous studies (21.3%). A statistically significant difference was found for positivity between breeds (p < 0.05). There is also a higher probability of older animals being positive compared to younger ones (p < 0.05). The region where Mertolenga animals are located is shown to have a significant impact on positivity (p < 0.05). Thus, the development of sustainable T. annulata control strategies and their implementation, adapted to the epidemiological conditions of higher risk, will be extremely important.

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.

Genome-Wide Population Structure and Selection Signatures of Yunling Goat Based on RAD-seq

Simple Summary

Goats are important domestic animals that provide meat, milk, fur, and other products for humans. The demand for these products has increased in recent years. Disease resistance among goat breeds is different, but the genetic basis of the differences in resistance to diseases is still unclear and needs to be further studied. In this study, many genes and pathways related to immunity and diseases were identified to be under positive selection between Yunling and Nubian goats using RAD-seq technology. This study on the selection signatures of Yunling goats provides the scientific basis and technical support for the breeding of domestic goats for disease resistance, which has important social and economic significance.

Abstract

Animal diseases impose a huge burden on the countries where diseases are endemic. Conventional control strategies of vaccines and veterinary drugs are to control diseases from a pharmaceutical perspective. Another alternative approach is using pre-existing genetic disease resistance or tolerance. We know that the Yunling goat is an excellent local breed from Yunnan, southwestern China, which has characteristics of strong disease resistance and remarkable adaptability. However, genetic information about the selection signatures of Yunling goats is limited. We reasoned that the genes underlying the observed difference in disease resistance might be identified by investigating selection signatures between two different goat breeds. Herein, we selected the Nubian goat as the reference group to perform the population structure and selection signature analysis by using RAD-seq technology. The results showed that two goat breeds were divided into two clusters, but there also existed gene flow. We used Fst (F-statistics) and π (pi/θπ) methods to carry out selection signature analysis. Eight selected regions and 91 candidate genes were identified, in which some genes such as DOK2, TIMM17A, MAVS, and DOCK8 related to disease and immunity and some genes such as SPEFI, CDC25B, and MIR103 were associated with reproduction. Four GO (Gene Ontology) terms (GO:0010591, GO:001601, GO:0038023, and GO:0017166) were associated with cell migration, signal transduction, and immune responses. The KEGG (Kyoto Encyclopedia of Genes and Genomes) signaling pathways were mainly associated with immune responses, inflammatory responses, and stress reactions. This study preliminarily revealed the genetic basis of strong disease resistance and adaptability of Yunling goats. It provides a theoretical basis for the subsequent genetic breeding of disease resistance of goats.

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.

Susceptibility to disease (tropical theileriosis) is associated with differential expression of host genes that possess motifs recognised by a pathogen DNA binding protein

Background

Knowledge of factors that influence the outcome of infection are crucial for determining the risk of severe disease and requires the characterisation of pathogen-host interactions that have evolved to confer variable susceptibility to infection. Cattle infected by Theileria annulata show a wide range in disease severity. Native (Bos indicus) Sahiwal cattle are tolerant to infection, whereas exotic (Bos taurus) Holstein cattle are susceptible to acute disease.

Methodology/Principal findings

We used RNA-seq to assess whether Theileria infected cell lines from Sahiwal cattle display a different transcriptome profile compared to Holstein and screened for altered expression of parasite factors that could generate differences in host cell gene expression.

Significant differences (<0.1 FDR) in the expression level of a large number (2211) of bovine genes were identified, with enrichment of genes associated with Type I IFN, cholesterol biosynthesis, oncogenesis and parasite infection. A screen for parasite factors found limited evidence for differential expression. However, the number and location of DNA motifs bound by the TashAT2 factor (TA20095) were found to differ between the genomes of B. indicus vs. B. taurus, and divergent motif patterns were identified in infection-associated genes differentially expressed between Sahiwal and Holstein infected cells.

Conclusions/Significance

We conclude that divergent pathogen-host molecular interactions that influence chromatin architecture of the infected cell are a major determinant in the generation of gene expression differences linked to disease susceptibility.

Inherited Tolerance in Cattle to the Apicomplexan Protozoan Theileria parva is Associated with Decreased Proliferation of Parasite-Infected Lymphocytes

Theileria parva is the causative agent of East Coast fever and Corridor disease, which are fatal, economically important diseases of cattle in eastern, central and southern Africa. Improved methods of control of the diseases are urgently required. The parasite transforms host lymphocytes, resulting in a rapid, clonal expansion of infected cells. Resistance to the disease has long been reported in cattle from T. parva-endemic areas. We reveal here that first- and second-generation descendants of a single Bos indicus bull survived severe challenge with T. parva, (overall survival rate 57.3% compared to 8.7% for unrelated animals) in a series of five field studies. Tolerant cattle displayed a delayed and less severe parasitosis and febrile response than unrelated animals. The in vitro proliferation of cells from surviving cattle was much reduced compared to those from animals that succumbed to infection. Additionally, some pro-inflammatory cytokines such as IL1β, IL6, TNFα or TGFβ which are usually strongly expressed in susceptible animals and are known to regulate cell growth or motility, remain low in tolerant animals. This correlates with the reduced proliferation and less severe clinical reactions observed in tolerant cattle. The results show for the first time that the inherited tolerance to T. parva is associated with decreased proliferation of infected lymphocytes. The results are discussed in terms of whether the reduced proliferation is the result of a perturbation of the transformation mechanism induced in infected cells or is due to an innate immune response present in the tolerant cattle.

From Bench to Field: A Guide to Formulating and Evaluating Anti-Tick Vaccines Delving beyond Efficacy to Effectiveness

Ticks are ubiquitous blood-sucking ectoparasites capable of transmitting a wide range of pathogens such as bacteria, viruses, protozoa, and fungi to animals and humans. Although the use of chemicals (acaricides) is the predominant method of tick-control, there are increasing incidents of acaricide tick resistance. Furthermore, there are concerns over accumulation of acaricide residues in meat, milk and in the environment. Therefore, alternative methods of tick-control have been proposed, of which anti-tick cattle vaccination is regarded as sustainable and user-friendly. Over the years, tremendous progress has been made in identifying and evaluating novel candidate tick vaccines, yet none of them have reached the global market. Until now, Bm86-based vaccines (Gavac™ in Cuba and TickGARD^PLUS™ Australia-ceased in 2010) are still the only globally commercialized anti-tick vaccines. In contrast to Bm86, often, the novel candidate anti-tick vaccines show a lower protection efficacy. Why is this so? In response, herein, the potential bottlenecks to formulating efficacious anti-tick vaccines are examined. Aside from Bm86, the effectiveness of other anti-tick vaccines is rarely assessed. So, how can the researchers assess anti-tick vaccine effectiveness before field application? The approaches that are currently used to determine anti-tick vaccine efficacy are re-examined in this review. In addition, a model is proposed to aid in assessing anti-tick vaccine effectiveness. Finally, based on the principles for the development of general veterinary vaccines, a pipeline is proposed to guide in the development of anti-tick vaccines.

Abundance and Expression of Shiga Toxin Genes in Escherichia coli at the Recto-Anal Junction Relates to Host Immune Genes

Shiga toxin (Stx) is the main virulence factor of Shiga toxin-producing Escherichia coli (STEC), and ruminants are the main reservoir of STEC. This study assessed the abundance and expression of Stx genes and the expression of host immune genes, aiming to determine factors affecting these measures and potential gene markers to differentiate Stx gene expression in the recto-anal junction of feedlot beef cattle. Rectal tissue and content samples were collected from 143 feedlot steers of three breeds (Angus, Charolais, and Kinsella Composite) over 2 consecutive years 2014 (n=71) and 2015 (n=72). The abundance and expression of stx1 and stx2 were quantified using qPCR and reverse-transcription-qPCR (RT-qPCR), respectively. Four immune genes (MS4A1, CCL21, CD19, and LTB), previously reported to be down-regulated in super-shedder cattle (i.e., > 10⁴ CFU g^-1) were selected, and their expression was evaluated using RT-qPCR. The stx1 gene abundance was only detected in tissue samples collected in year 2 and did not differ among breeds. The stx2 gene was detected in STEC from all samples collected in both years and did not vary among breeds. The abundance of stx1 and stx2 differed (P < 0.001) in content samples collected across breeds (stx1:AN>CH>KC, stx2: AN=CH>KC) in year 1, but not in year 2. Expression of stx2 was detected in 13 RAJ tissue samples (2014: n=6, 2015: n=7), while expression of stx1 was not detected. Correlation analysis showed that the expression of stx2 was negatively correlated with the expression of MS4A1 (R=-0.56, P=0.05) and positively correlated with the expression of LTB (R=0.60, P=0.05). The random forest model and Boruta method revealed that expression of selected immune genes could be predictive indicators of stx2 expression with prediction accuracy of MS4A1 >LTB >CCL21 >CD19. Our results indicate that the abundance of Stx could be affected by cattle breed and sampling year, suggesting that host genetics and environment may influence STEC colonization of the recto-anal junction of feedlot cattle. Additionally, the identified relationship between expressions of host immune genes and stx2 suggests that the host animal may regulate stx2 expression in colonizing STEC through immune functions.

Cross-sectional survey of cattle haemopathogens in Constantine, Northeast Algeria

This aim of the present study was to estimate the prevalence of haemopathogens in cattle in Beni Hamidene locality, district of Constantine (Νortheastern Algeria). Between June and October 2014, 169 bovines from 25 farms were included in this survey, 32 (18.9%) among them were suspected of piroplasmosis and/or anaplasmosis. Infection prevalences were estimated by microscopic examination of Giemsa‐stained blood smears and blood samples from all included cattle (n = 169). Animals were infected by Theileria annulata (65/169; 38.46%), Anaplasma marginale (22/169; 13%) and Babesia bovis (5/169; 3%). Two co‐infection patterns were found: Theileria annulata/Anaplasma marginale (7.69%) and Theileria annulata/Babesia bovis (1.18%). Only one farm had no cattle infected by any of the haemopathogens. There was a signification difference of T. annulata infection prevalence according to age category (p =.04). These results emphasised mainly the presence of bovine tropical theileriosis in northeastern, Beni Hamidene locality, province of Constantine, Algeria.

Intestinal transcriptomes in Kazakh sheep with different haplotypes after experimental Echinococcus granulosus infection

Cystic echinococcosis (CE) is a chronic zoonosis caused by infection with the larval stage of the cestode Echinococcus granulosus. As the intermediate host, sheep are highly susceptible to this disease. Our previous studies have shown that sheep with haplotype MHC Mva Ibc-Sac IIab-Hin1I ab were resistant to CE infection, while their counterparts without this haplotype were not. In order to reveal the molecular mechanism of resistance in Kazakh sheep, after selecting the differential miRNA in our previous study, herein, transcriptome analyses were conducted to detect the differential expression genes in the intestinal tissue of Kazakh sheep with resistant and non-resistant MHC haplotypes, after peroral infection with E. granulosus eggs. A total of 3835 differentially expressed genes were identified between the two groups, with 2229 upregulated and 1606 downregulated. Further function analysis showed that the most significant genes were related to both innate immune response and adaptive response participating in the defense against E. granulosus infection and the metabolic changes associated with it. The results suggest that genes related to lectin receptors, NK cells activation, chemokines, and tumor necrosis factor, may play important roles in the response of intestinal tissue to E. granulosus.

Expression of cytokine genes at tick attachment and control sites of Namaqua Afrikaner, Dorper and South African Mutton Merino sheep

Cytokines are immune response components important in innate immunity and inflammatory response. They are harnessed as part of local immunological responses by animals to combat local infections and/or infestations. This study investigated expression of four selected cytokine genes, namely, interleukin 1 beta (IL-1β), chemokine C-C ligand 2 (CCL2), chemokine C-C ligand 26 (CCL26) and interleukin 8 (IL-8), at tick attachment and control sites in a South African indigenous sheep breed the Namaqua Afrikaner (NA) and two commercial breeds, the Dorper and South African Mutton Merino (SAMM). The NA was previously shown to be more resistant to infestation by ticks than the two commercial breeds. NA ewes expressed IL-1β more at tick attachment sites compared to Dorpers. The NA breed was also more likely to upregulate the expression of the CCL2, CCL26 and IL-8 genes at tick attachment sites compared to control sites than the other breeds. The results of this study gave an indication that cytokines are involved in immune responses to tick challenge and laid a foundation for further studies under controlled challenge conditions.

Interaction between transforming Theileria parasites and their host bovine leukocytes

Theileria are tick-transmitted parasites that cause often fatal leuko-proliferative diseases in cattle called tropical theileriosis (T. annulata) and East Coast fever (T. parva). However, upon treatment with anti-theilerial drug-transformed leukocytes die of apoptosis indicating that Theileria-induced transformation is reversible making infected leukocytes a powerful example of how intracellular parasites interact with their hosts. Theileria-transformed leukocytes disseminate throughout infected cattle causing a cancer-like disease and here, we discuss how cytokines, noncoding RNAs and oncometabolites can contribute to the transformed phenotype and disease pathology.

Poly I:C stimulation in-vitro as a marker for an antiviral response in different cell types generated from Buffalo (Bubalus bubalis)

The innate immune system is activated upon virus invasion of a host cell by recognizing viral component, such as dsRNA through specific receptors, resulting in the production of type- I IFNs, which confer an antiviral state within the invaded as well as surrounding cells. In the present study, fibroblast, monocyte and macrophage cells derived from water Buffalo (Bubalus bubalis) were exposed to a synthetic dsRNA analogue, poly I:C to mimic viral invasion in each cell type. Recognition of poly I:C through cytosolic helicase receptors RIG-I and MDA5 molecule lead to the activation of the RLR pathway, subsequently activating the MAVS-IRF3/7 cascade and the production of antiviral effector molecule like IFNβ and ISGs. Within the different cell types, we identified variability in RLR receptor and IFNβ expression after poly I:C administration. Fibroblasts responded quickly and strongly with IFNβ production, followed by macrophages and monocytes. Despite absolute expression variability among different cell types the expression trend of RLRs pathway genes were similar. Length of poly I:C molecule also influence IFNβ expression in response of RLR pathway. Short (LMW) poly I:C induce stronger IFN-β expression in myeloid (macrophage and monocyte) cells. In contrast long (HMW) poly I:C preferably elicit higher IFNβ expression in non-myeloid (fibroblast) cell. Therefore, MDA5 and RIG-1 plays an indispensable role in eliciting antiviral response in non- immune (fibroblast) host cell. Thus, stimulation of RLR pathway with suitable and potentially cell-type specific agonist molecules successfully elicit antiviral state in the host animal, with fibroblasts conferring a stronger antiviral state compared with the monocytes and macrophages.

First Molecular detection of Theileria annulata in Bangladesh

In South Asia, Theileria annulata is known to be less pathogenic to local breeds of Bos indicus cattle comparing to Bos taurus cattle and some of mix breeds between them. Seroepidemiological surveys have revealed high sero-prevalence of T. annulata in asymptomatic local breeds of cattle in Bangladesh. Therefore, these asymptomatic infection in local breeds can be infectious sources to more sensitive breeds. In this study, 59 bloods of cattle showing no symptom were screened by species specific PCRs for hemoto-protozoan parasites, to prove the existence of T. annulata parasite in asymptomatic cattle in Bangladesh. The T. annulata infection was confirmed along with other parasitic species, and this is the first report of T. annulata DNA detection in Bangladesh.

Molecular and Antigenic Properties of Mammalian Cell-Expressed Theileria parva Antigen Tp9

East Coast Fever (ECF), caused by the tick-borne apicomplexan parasite Theileria parva, is a leading cause of morbidity and mortality in cattle of sub-Saharan Africa. The infection and treatment method (ITM) is currently the only vaccine available to control T. parva. Although ITM elicits levels of protection, its widespread adoption is limited by costs, laborious production process, and antibiotic co-treatment requirement, necessitating the development of a more sustainable vaccine. To this end, efforts have been concentrated in the identification of new T. parva vaccine antigens and in the development of suitable platforms for antigen expression. In this study, we investigated the molecular and antigenic properties of T. parva antigen Tp9 expressed by mammalian cells. Data indicate that Tp9 contains a signal peptide that is weakly functional in mammalian cells. Thus, Tp9 secretion from mammalian cells increased 10-fold after the native signal peptide was replaced with the human tissue plasminogen activator signal peptide (tPA). Sera from all T. parva-immune cattle recognized this recombinant, secreted Tp9. Additionally, PBMC from ITM-immunized cattle produced significant (p < 0.05) amounts of IFNγ following ex vivo exposure to Tp9, but this response varied between cattle of different MHC class I and class II genotypes. In addition, depletion experiments demonstrated that IFNγ to Tp9 was primarily produced by CD4⁺ T cells. Molecular analysis demonstrated that Tp9 presents a signal peptide that is weakly functional in mammalian cells, suggesting that it remains within lymphocytes during infection. Tp9 secretion from mammalian cells was substantially increased when the tPA secretion signal sequence was substituted for the native secretion signal sequence. Using full-length, recombinant Tp9 secreted from mammalian cells, we demonstrated that T. parva-immune cattle develop both humoral and cellular immune responses to this antigen. Collectively, these results provide rationale for further evaluation of Tp9 as a component of a T. parva subunit vaccine.

Combining Landscape Genomics and Ecological Modelling to Investigate Local Adaptation of Indigenous Ugandan Cattle to East Coast Fever

East Coast fever (ECF) is a fatal sickness affecting cattle populations of eastern, central, and southern Africa. The disease is transmitted by the tick Rhipicephalus appendiculatus, and caused by the protozoan Theileria parva parva, which invades host lymphocytes and promotes their clonal expansion. Importantly, indigenous cattle show tolerance to infection in ECF-endemically stable areas. Here, the putative genetic bases underlying ECF-tolerance were investigated using molecular data and epidemiological information from 823 indigenous cattle from Uganda. Vector distribution and host infection risk were estimated over the study area and subsequently tested as triggers of local adaptation by means of landscape genomics analysis. We identified 41 and seven candidate adaptive loci for tick resistance and infection tolerance, respectively. Among the genes associated with the candidate adaptive loci are PRKG1 and SLA2. PRKG1 was already described as associated with tick resistance in indigenous South African cattle, due to its role into inflammatory response. SLA2 is part of the regulatory pathways involved into lymphocytes' proliferation. Additionally, local ancestry analysis suggested the zebuine origin of the genomic region candidate for tick resistance.

Theileria annulata seroprevalence among different cattle breeds in Rajshahi Division, Bangladesh

An epidemiological survey of Theileria annulata infection was undertaken in a cattle population in Rajshahi Division, Bangladesh. The local cattle breeds from the area (North Bengal Gray and Deshi) and crosses between the local breeds and Holstein cattle were predominantly screened. In total, 192 cattle serum samples were collected in two areas of Rajshahi Division, the Rajshahi District (n=147) and Natore District (n=45). The samples were screened with an enzyme-linked immunosorbent assay using T. annulata surface protein (TaSP) as the antigen. The seroprevalence was 80.0% (36/45) in Natore and 20.4% (30/147) in Rajshahi. A logistic regression analysis showed that the sampling location was significantly associated with seropositivity, whereas age, sex and breed were not. Although the logistic regression analysis did not show a linear dependence on age, we considered age-specific seroprevalence separately in the two districts. Seroprevalence did not differ significantly among age categories in the Natore District. In contrast, all the cattle <1 year old in the Rajshahi District were seronegative (11/11). Seroprevalence in the 1- and 2-year-old cattle was significantly lower in the Rajshahi District than in the Natore District. In the older age categories (3, 4 and >5 years), seroprevalence did not differ significantly between the Natore and Rajshahi Districts. These results suggest that the cattle in the Rajshahi District were sporadically exposed to T. annulata, whereas most cattle in the Natore District became infected during an early phase of life.

A genome-wide association study for clinical mastitis in first parity US Holstein cows using single-step approach and genomic matrix re-weighting procedure

Clinical mastitis (CM) is one of the health disorders with large impacts on dairy farming profitability and animal welfare. The objective of this study was to perform a genome-wide association study (GWAS) for CM in first-lactation Holstein. Producer-recorded mastitis event information for 103,585 first-lactation cows were used, together with genotype information on 1,361 bulls from the Illumina BovineSNP50 BeadChip. Single-step genomic-BLUP methodology was used to incorporate genomic data into a threshold-liability model. Association analysis confirmed that CM follows a highly polygenic mode of inheritance. However, 10-adjacent-SNP windows showed that regions on chromosomes 2, 14 and 20 have impacts on genetic variation for CM. Some of the genes located on chromosome 14 (LY6K, LY6D, LYNX1, LYPD2, SLURP1, PSCA) are part of the lymphocyte-antigen-6 complex (LY6) known for its neutrophil regulation function linked to the major histocompatibility complex. Other genes on chromosome 2 were also involved in regulating immune response (IFIH1, LY75, and DPP4), or are themselves regulated in the presence of specific pathogens (ITGB6, NR4A2). Other genes annotated on chromosome 20 are involved in mammary gland metabolism (GHR, OXCT1), antibody production and phagocytosis of bacterial cells (C6, C7, C9, C1QTNF3), tumor suppression (DAB2), involution of mammary epithelium (OSMR) and cytokine regulation (PRLR). DAVID enrichment analysis revealed 5 KEGG pathways. The JAK-STAT signaling pathway (cell proliferation and apoptosis) and the 'Cytokine-cytokine receptor interaction' (cytokine and interleukines response to infectious agents) are co-regulated and linked to the 'ABC transporters' pathway also found here. Gene network analysis performed using GeneMania revealed a co-expression network where 665 interactions existed among 145 of the genes reported above. Clinical mastitis is a complex trait and the different genes regulating immune response are known to be pathogen-specific. Despite the lack of information in this study, candidate QTL for CM were identified in the US Holstein population.

Comparative analysis of innate immune response following in vitro stimulation of sheep and goat peripheral blood mononuclear cells with bluetongue virus - serotype 23

Bluetongue is an infectious disease caused by bluetongue virus (BTV), which affects sheep, goat, cattle and certain wild ruminants. However severe clinical signs are usually seen with significant mortality in sheep than cattle and goat. To date, comparative studies on innate immune responses of sheep and goat infected with BTV is lacking. In this study, we compared the innate immune response of sheep and goat by infecting the peripheral blood mononuclear cells (PBMCs) with BTV serotype 23. In our study, we observed that sheep PBMCs supports higher virus replication than goat PBMCs. To delineate the role of innate immune response in differential viral replication observed in this study, we examined TLR3 (Receptor for dsRNA virus) mRNA expression and cytokine profiles (IL-1β, Il-6, IL-8, Il-10, IL-12p40, TNF-α, IFN-γ and IFN-α) following Poly I:C (TLR3 ligand) stimulation and BTV 23 infection. In our present study, sheep PBMCs had significantly higher TLR3 mRNA levels, TLR3 specific ligand (Poly I:C) stimulation resulted in increased levels of IFN-γ at transcriptional and translational levels along with IL-8 and IL-10 at transcriptional levels. Whereas, the levels of TNF-α was higher in goat PBMCs at transcriptional levels. BTV infected sheep PBMCs expressed significantly higher levels of IFN-γ at transcriptional and translational levels along with IL-6, IL-8 and IL-10 at transcriptional levels. Whereas the expression levels of TNF-α and IFN-α at transcriptional and translational levels were significantly high in goat PBMCs. To examine the potential factor for consistent increase in the expression of TNF-α, we sequenced the promoter region of TNF-α and identified a total of five single nucleotide polymorphisms (SNP) and one indel in goat TNF-α promoter region. Luciferase assay for transcriptional activity of the promoter showed that goat TNF-α has significantly enhanced transcriptional activity in comparison with sheep TNF-α promoter. Altogether, our data suggests that the expression levels of TNF-α and IFN-α and/or IL-10 plays crucial role in replication of BTV 23.

Use of gene expression data for predicting continuous phenotypes for animal production and breeding

Traits such as disease resistance are costly to evaluate and slow to improve using current methods. Analysis of gene expression profiles (e.g. DNA microarrays) has potential for predicting such phenotypes and has been used in an analogous way to classify cancer types in human patients. However, doubts have been raised regarding the use of classification methods with microarray data for this purpose. Here we propose a method using random regression with cross validation, which accounts for the distribution of variation in the trait and utilises different subsets of patients or animals to perform a complete validation of predictive ability. Published breast tumour data were used to test the method. Despite the small dataset (n < 100), the new approach resulted in a moderate but significant correlation between the predicted and actual phenotypes (0.32). Binary classification of the predicted phenotypes yielded similar classification error rates to those found by other authors (35%). Unlike other methods, the new method gave a quantitative estimate of phenotype that could be used to rank animals and select those with extreme phenotypic performance. Use of the method in an optimal way using larger sample sizes, and combining DNA microarrays and other testing platforms, is recommended.

Comparative in vitro toll-like receptor ligand induced cytokine profiles of Toda and Murrah buffaloes-Identification of tumour necrosis factor alpha promoter polymorphism

The objective of this study was to assess cytokine production upon activation of pattern recognition receptors responsible for sensing bacterial and viral pathogen associated molecular patterns in two genetically diverse buffalo breeds, Toda and Murrah. A very limited molecular-epidemiological analysis showed a higher prevalence of Anaplasma and Theileria in Murrah than Toda buffaloes. Toda buffalo peripheral blood mononuclear cells (PBMC) produced significantly higher levels of IFN γ and/or TNF α mRNAs in response to peptidoglycan, poly I:C, lipopolysaccharide, imiquimod and CpG. Flagellin stimulation did not result in any significant differences in the expression levels of the cytokines tested between these breeds. The levels of ligand induced IFN γ and TNF α mRNA and proteins also correlated except when induced with CpG. The proximal promoter region of TNF α across these two breeds were also sequenced to detect SNPs and promoter assay performed to determine their role in altering the transcriptional activity. Two polymorphisms were identified at -737 (T/A) and -1092 (G/T) positions in Toda buffalo TNF α promoter and promoter assay revealed higher transcription activity in Toda buffalos than in Murrah. This suggests that disease tolerance of these buffalo breeds could be due to the differences in their cytokine transcription levels in response to the respective PAMPs that may be at least in part determined by polymorphisms in the cytokine promoter regions.

Serum acute phase proteins in control and Theileria annulata infected water buffaloes (Bubalus bubalis)

This study was carried out to ascertain the changes in acute phase proteins (APPs) and pro-inflammatory cytokines in Theileria annulata infected water buffalo. Thirty infected water buffaloes and 20 parasitologically free were used. In the present study there was significant (P ≤ 0.05) increase in haptoglobin (Hp), serum amyloid A (SAA), ceruloplasmin, α1-acid glycoprotein (AGP) and fibrinogen levels (2.18 ± 0.29 g/l, 156.58 ± 3.48 mg/l, 31.23 ± 1.25mg/dl, 370.23 ± 33.21 mg/l and 16.17 ± 1.18 g/l, respectively) in T. annulata infected water buffaloes when compared to healthy ones (0.13 ± 0.01 g/l, 23.9 ± 0.56 mg/l, 21.23 ± 1.21 mg/dl, 240.53 ± 22.45 mg/l and 4.2 ± 0.1 6g/l, respectively). Moreover, there was significant (P ≤ 0.05) increase in the levels of TNF-α, IL-1α, IL-6, IL-12, IL-1β and IFN-γ (2.55 ± 0.12 ng/ml, 98.32 ± 4.21 pg/ml, 152.32 ± 5.62 pg/ml, 26.44 ± 1.43 ng/ml, 240.33 ± 20.45 pg/ml and 123.65 ± 5.67 pg/ml, respectively) in T. annulata infected water buffaloes when compared to healthy ones (0.42 ± 0.04 ng/ml, 55.32 ± 3.21 pg/ml, 88.23 ± 3.21 pg/ml, 7.45 ± 0.67 ng/ml, 98.33 ± 3.45 pg/ml and 34.76 ± 1.56 pg/ml, respectively). There was also significant decrease (P ≤ 0.05) in the Hb content, PCV%, RBCs and WBCs counts in the diseased water buffaloes compared to the control ones. Neutropenia, eosinopenia, lymphopenia, monocytopenia and thrombocytopenia were also recorded. The biochemical changes revealed significant (P ≤ 0.05) elevation in the levels of AST, ALT, ALP, LDL-c, VLDL-c, BHBA and NEFA, with significant (P ≤ 0.05) decrease in the levels of total proteins, albumin, globulins, cholesterol, triglyceride, glucose, G6PD, calcium and phosphorus in T. annulata infected water buffaloes when compared to healthy ones. It could be concluded that APPs and pro-inflammatory cytokines could be used as a valuable biomarkers in T. annulata infected water buffaloes (Bubalus bubalis).

Tick-borne diseases in cattle: applications of proteomics to develop new generation vaccines

Tick-borne diseases (TBDs) affect 80% of the world's cattle population, hampering livestock production throughout the world. Livestock industry is important to rural populations not only as food supply, but also as a source of income. Tick control is usually achieved by using acaricides which are expensive, deleterious to the environment and can induce chemical resistance of vectors; the development of more effective and sustainable control methods is therefore required. Theileriosis, babesiosis, anaplasmosis and heartwater are the most important TBDs in cattle. Immunization strategies are currently available but with variable efficacy. To develop a new generation of vaccines which are more efficient, cheaper and safer, it is first necessary to better understand the mechanisms by which these parasites are transmitted, multiply and cause disease; this becomes especially difficult due to their complex life cycles, in vitro culture conditions and the lack of genetic tools to manipulate them. Proteomics and other complementary post-genomic tools such as transcriptomics and metabolomics in a systems biology context are becoming key tools to increase knowledge on the biology of infectious diseases. Herein, we present an overview of the so called "Omics" studies currently available on these tick-borne pathogens, giving emphasis to proteomics and how it may help to discover new vaccine candidates to control TBDs.

Living with the enemy or uninvited guests: functional genomics approaches to investigating host resistance or tolerance traits to a protozoan parasite, Theileria annulata, in cattle

Many breeds of cattle with long histories of living in areas of endemic disease have evolved mechanisms that enable them to co-exist with specific pathogens. Understanding the genes that control tolerance and resistance could provide new strategies to improve the health and welfare of livestock. Around one sixth of the world cattle population is estimated to be at risk from one of the most debilitating tick-borne diseases of cattle, caused by the protozoan parasite, Theileria annulata. The parasite mainly infects cells of the myeloid lineage which are also the main producers of inflammatory cytokines. If an infectious or inflammatory insult is sufficiently great, inflammatory cytokines produced by macrophages enter the circulation and induce an acute phase proteins (APP) response. The Bos taurus Holstein breed produces higher and more prolonged levels of inflammatory cytokine induced APP than the Bos indicus Sahiwal breed in response to experimental infection with T. annulata. The Sahiwal exhibits significantly less pathology and survives infection, unlike the Holstein breed. Therefore, we hypothesised that the causal genes were likely to be expressed in macrophages and control the production of inflammatory cytokines. A functional genomics approach revealed that the transcriptome profile of the B. taurus macrophages was more associated with an inflammatory programme than the B. indicus macrophages. In particular the most differentially expressed gene was a member of the signal regulatory protein (SIRP) family. These are mainly expressed on myeloid cell surfaces and control inflammatory responses. Other differentially expressed genes included bovine major histocompatibility complex (MHC) (BoLA) class II genes, particularly BoLA DQ, and transforming growth factor (TGF)B2. We are now exploring whether sequence and functional differences in the bovine SIRP family may underlie the resistance or tolerance to T. annulata between the breeds. Potentially, our research may also have more general implications for the control of inflammatory processes against other pathogens. Genes controlling the balance between pathology and protection may determine how livestock can survive in the face of infectious onslaught. Next generation sequencing and RNAi methodologies for livestock species will bring new opportunities to link diversity at the genome level to functional differences in health traits in livestock species.

TGF-b2 induction regulates invasiveness of Theileria-transformed leukocytes and disease susceptibility

Theileria parasites invade and transform bovine leukocytes causing either East Coast fever (T. parva), or tropical theileriosis (T. annulata). Susceptible animals usually die within weeks of infection, but indigenous infected cattle show markedly reduced pathology, suggesting that host genetic factors may cause disease susceptibility. Attenuated live vaccines are widely used to control tropical theileriosis and attenuation is associated with reduced invasiveness of infected macrophages in vitro. Disease pathogenesis is therefore linked to aggressive invasiveness, rather than uncontrolled proliferation of Theileria-infected leukocytes. We show that the invasive potential of Theileria-transformed leukocytes involves TGF-b signalling. Attenuated live vaccine lines express reduced TGF-b2 and their invasiveness can be rescued with exogenous TGF-b. Importantly, infected macrophages from disease susceptible Holstein-Friesian (HF) cows express more TGF-b2 and traverse Matrigel with great efficiency compared to those from disease-resistant Sahiwal cattle. Thus, TGF-b2 levels correlate with disease susceptibility. Using fluorescence and time-lapse video microscopy we show that Theileria-infected, disease-susceptible HF macrophages exhibit increased actin dynamics in their lamellipodia and podosomal adhesion structures and develop more membrane blebs. TGF-b2-associated invasiveness in HF macrophages has a transcription-independent element that relies on cytoskeleton remodelling via activation of Rho kinase (ROCK). We propose that a TGF-b autocrine loop confers an amoeboid-like motility on Theileria-infected leukocytes, which combines with MMP-dependent motility to drive invasiveness and virulence.

Theileria annulata causes tropical theileriosis that is endemic in cattle in North Africa, the Middle East, India and China. T. parva causes East Coast fever that is prevalent in East and Southern Africa. In endemic countries indigenous cattle are more resistant to pathology, but produce little meat and milk and attempts to improve output by importing European and American breeds have failed due to a high susceptibility to these diseases that are often rapidly fatal. We examined T. annulata-transformed macrophages isolated from disease resistant Sahiwal compared to disease-susceptible Holstein-Friesian (HF) cattle, for their capacity to traverse synthetic extra-cellular matrix in vitro. The invasive capacity of all transformed macrophages was TGF-b dependent, but those of disease-susceptible HF animals invaded better i.e. they were more aggressive. The greater invasive capacity of HF transformed macrophages matched their increased production of TGF-b2, since levels of TGF-b1, and all three TGF-b receptors, were the same as in transformed macrophages isolated from disease-resistant Sahiwal animals. TGF-b2 production therefore likely renders Theileria-transformed leukocytes more pathogenic and consistently, in a live attenuated line used to vaccinate against tropical theileriosis transcripts of TGF-b2 and those of a significant number of TGF-target genes drop and consequently, TGF-b-mediated invasiveness decreases.

The protozoan parasite Theileria annulata alters the differentiation state of the infected macrophage and suppresses musculoaponeurotic fibrosarcoma oncogene (MAF) transcription factors

The tick-borne protozoan parasite Theileria annulata causes a debilitating disease of cattle called Tropical Theileriosis. The parasite predominantly invades bovine macrophages (m phi) and induces host cell transformation by a mechanism that has not been fully elucidated. Infection is associated with loss of characteristic m phi functions and phenotypic markers, indicative of host cell de-differentiation. We have investigated the effect of T. annulata infection on the expression of the m phi differentiation marker c-maf. The up-regulation of c-maf mRNA levels observed during bovine monocyte differentiation to m phi was suppressed by T. annulata infection. Furthermore, mRNA levels for c-maf and the closely related transcription factor mafB were significantly lower in established T. annulata-infected cell-lines than in bovine monocyte-derived m phi. Treatment of T. annulata-infected cells with the theileriacidal drug buparvaquone induced up-regulation of c-maf and mafB, which correlated with altered expression of down-stream target genes, e.g. up-regulation of integrin B7 and down-regulation of IL12A. Furthermore, T. annulata infection is associated with the suppression of the transcription factors, Pu.1 and RUNX1, and colony stimulating factor 1 receptor (CSF1R) which are also involved in the regulation of monocyte/m phi differentiation. We believe these results provide the first direct evidence that T. annulata modulates the host m phi differentiation state, which may diminish the defence capabilities of the infected cell and/or promote cell proliferation. Musculoaponeurotic fibrosarcoma oncogene (MAF) transcription factors play an important role in cell proliferation, differentiation and survival; therefore, regulation of these genes may be a major mechanism employed by T. annulata to survive within the infected m phi.

Study on acute phase proteins (haptoglobin, serum amyloid A, fibrinogen, and ceruloplasmin) changes and their diagnostic values in bovine tropical theileriosis

This study was conducted to assess the pattern of changes and the relative value of acute phase proteins (haptoglobin (Hp), serum amyloid A (SAA), ceruloplasmin and fibrinogen) in bovine tropical theileriosis. The diseased group comprised 50 dairy Holstein cattle, 2-3 years old, naturally infected with Theileria annulata. Infected animals were divided into four subgroups with different parasitemia rates (<1%, 1-3%, 3-5%, >5%). As a control group, 20 uninfected cattle were also sampled. Blood samples were collected and all measurements were done using validated methods. There were significant differences in red blood cells (RBCs), packed cell volume (PCV), hemoglobin (Hb) and concentrations of Hp, SAA, ceruloplasmin and fibrinogen between healthy cattle and those infected with T. annulata with different parasitemia rates (P < 0.05). As the parasitemia rate increased in infected cattle, a significant decrease was observed in RBCs, PCV, and Hb. In contrast, with increase in the parasitemia rate, a significant increase in the mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), Hp, SAA, ceruloplasmin, and fibrinogen was evident. The optimal cut-off point was set by the receiver operating characteristics (ROC) method to >5.68 microg/ml for SAA, >0.16 g/l for Hp, >0.064 g/l for ceruloplasmin and >4.00 g/l for fibrinogen with corresponding 84% sensitivity and 100% specificity for SAA, 76% sensitivity and 100% specificity for Hp, 84% sensitivity and 80% specificity for ceruloplasmin and 40% sensitivity and 100% specificity for fibrinogen. SAA had the highest sensitivity and specificity and was diagnosed to be a suitable indicator of APPs changes in bovine theileriosis.

Transcriptional response of Mexican axolotls to Ambystoma tigrinum virus (ATV) infection

Background

Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).

Result

At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity.

Conclusion

Although A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridovirus in adult Xenopus. We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoviruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.

Review: Innate immunity to tropical theileriosis

The intracellular protozoan parasite Theileria annulata causes a severe, and often fatal, disease of pure and cross-bred cattle in tropical and subtropical countries. The present review refers to the importance of innate immunity as far as it is known to date in this infectious disease. Specifically, macrophages and the mediators produced by these cells are outlined. In addition, the latest findings concerning cattle breed differences in susceptibility to T. annulata infection in relation to macrophage activation are discussed.