Molecular, serological and parasitological survey of Theileria annulata in North Kordofan State, Sudan

Systematic Review and Meta-Analysis on Piroplasma spp. Infection and Co-infection with Anaplasma marginale in Domestic Ruminants from Algeria

BACKGROUND

Piroplasmosis and anaplasmosis stand out as the primary diseases affecting livestock during periods of tick activity. These vector-borne diseases continue to emerge worldwide, exerting a detrimental impact on both animal health and national economies. The purpose of this study is to assess the prevalence of Piroplasma spp. and its co-occurrence with Anaplasma marginale in domestic ruminants in Algeria.

METHODS

Three databases were systematically reviewed to identify eligible studies for the final meta-analysis, following the PRISMA statement. The 'meta' package in the R software was employed for the meta-analysis with the random effects model chosen for data pooling.

RESULTS

The meta-analysis encompasses 14 research papers spanning a 19-year period (2004-2023). Theileria spp. was identified in all studies, covering 1675 cattle, 190 sheep, and 128 goats, yielding an overall Theileria infection rate of 45% (95% CI 26-65%). Specifically, cattle had a 59% infection rate, while sheep and goats had rates of 18% and 20%, respectively. Babesia spp. was found in nine studies, involving 1183 cattle and 190 sheep, resulting in an overall Babesia infection rate of 7% (95% CI 4-15%), with cattle and sheep having rates of 10% and 3%, respectively. Notably, eight Piroplasma species T. annulata, T. orientalis, T. buffeli, T. equi, Theileria sp., B. bovis, B. bigemina, and B. occultans were detected in cattle, with T. annulata being the most prevalent at 54%. Regional disparities and host factors also impacted infection rates, with higher rates in Northeastern Algeria and among suspected disease cattle. Additionally, gender, age, and breed influenced cattle susceptibility to Theileria infection. Furthermore, six distinct co-infections between Piroplasma spp. and A. marginale were observed, with T. annulata/A. marginale identified in six studies, demonstrating an 8.3% co-infection rate.

CONCLUSION

This analysis offers crucial insights into the current status of Piroplasmosis and its co-infection with A. marginale in Algerian domestic ruminants, providing valuable data for surveillance and prevention strategies.

Bovine Tropical Theileriosis: An Update

Tick-borne diseases (TBDs) cause major economic losses and affect many domestic animals, mainly cattle and sheep, in tropical and subtropical regions. Tropical theileriosis is a TBD caused by a protozoon called Theileria annulata transmitted by several tick species of the genus Hyalomma. Clinical manifestations of theileriosis are expressed mainly as anorexia, febrile generalized lymphadenitis and anemia followed by lethargy, lacrimation, nasal discharge and exopthalmia. Anemia is a feature point in tropical bovine theileriosis and severity was positively related to parasitaemia rates. Fatality due to infection is greatly dependent on the overproduction of cytokines, such as TNF-α produced by the schizont-infected monocytes/macrophages and uninfected macrophages. Buparvaquone gave 86.66% clinical efficacy against Theileria annulata, but 97.1% and 95.2% efficacy against Theileria parva. In Theileriosis, hemolysis occurs due to isoantibody to RBC. To prevent this isoantibody lysis, immunosuppressive dose of steroid such as Dexamethasone@2.2 mg/kg.b.wt could be used.

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.

Theileria annulata SVSP455 interacts with host HSP60

Background

Theileria annulata, a transforming parasite, invades bovine B cells, dendritic cells and macrophages, promoting the uncontrolled proliferation of these cells. This protozoan evolved intricate strategies to subvert host cell signaling pathways related to antiapoptotic signaling to enable survival and proliferation within the host cells. However, the molecular mechanisms of the cell transformation induced by T. annulata remain largely unclear. Although some studies have predicted that the subtelomere-encoded variable secreted protein (SVSP) family plays roles in host-parasite interactions, the evidence for this is limited.

Methods

In the present study, the SVSP455 (TA05545) gene, a member of the SVSP gene family, was used as the target molecule. The expression pattern of SVSP455 in different life-cycle stages of T. annulata infection was explored using a quantitative real-time PCR assay, and the subcellular distribution of SVSP455 was observed using confocal microscopy. The host cell proteins interacting with SVSP455 were screened using the Y2H system, and their interactions were verified in vivo and in vitro using both bimolecular fluorescence complementation and confocal microscopy, and co-immunoprecipitation assays. The role played by SVSP455 in cell transformation was further explored by using overexpression, RNA interference and drug treatment experiments.

Results

The highest level of the SVSP455 transcript was detected in the schizont stage of T. annulata, and the protein was located both on the surface of schizonts and in the host cell cytoplasm. In addition, the interaction between SVSP455 and heat shock protein 60 was shown in vitro, and their link may regulate host cell apoptosis in T. annulata-infected cells.

Conclusion

Our findings are the first to reveal that T. annulata-secreted SVSP455 molecule directly interacts with both exogenous and endogenous bovine HSP60 protein, and that the interaction of SVSP455-HSP60 may manipulate the host cell apoptosis signaling pathway. These results provide insights into cancer-like phenotypes underlying Theilera transformation and therapeutics for protection against other pathogens.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05427-z.

Dried Blood Spots technology for veterinary applications and biological investigations: technical aspects, retrospective analysis, ongoing status and future perspectives

Dried Blood Spots (DBS) technology has become a valuable tool in medical studies, however, in veterinary and biological research DBS technology applications are still limited. Up-to-date no review has comprehensively integrated all the evidence existing across the fields, technologies and animal species. In this paper we summarize the current applications of DBS technology in the mentioned areas, and provide a scope of different types of dried sample carriers (cellulose and non-cellulose), sampling devices, applicable methods for analyte extraction and detection. Mammals, birds, insects and other species are represented as the study objects. Besides the blood, the review considers a variety of specimens, such as milk, saliva, tissue samples and others. The main applications of dried samples highlighted in the review include epidemiological surveys and monitoring for infections agents or specific antibodies for disease/vaccination control in households and wildlife. Besides the genetic investigations, the paper describes detection of environmental contaminants, pregnancy diagnosis and many other useful applications of animal dried samples. The paper also analyses dried sample stability and storage conditions for antibodies, viruses and other substances. Finally, recent developments and future research for DBS technology in veterinary medicine and biological sciences are discussed.

Prevalence and risk factors associated with tropical theileriosis in Egyptian dairy cattle

Background and Aim:

Theileria annulata is the most prevalent piroplasm infecting cattle across Egypt. Theileriosis is transmitted by ixodid ticks of the genus Hyalomma. This study aimed to estimate the prevalence of theileriosis in cattle and their associated risk factors for infection.

Materials and Methods:

A total of 570 blood samples were collected from cattle from five governorates (administrative districts) in Egypt and examined using a polymerase chain reaction assay to estimate the prevalence of tropical theileriosis and assess the associated risk factors

Results:

The overall prevalence rate was 16.49%, with the Alexandria district having the highest prevalence. The results revealed that the risk of theileriosis was elevated in older cattle (odds ratio [OR]=8.9, 95% confidence interval [CI]: 3.6-21.9), especially in summers (OR=3.07, 95% CI: 1.4-6.3). Cattle heavily infested with ticks were at particular risk (OR=3.05, 95% CI: 2.1-4.5), as were those to which acaricide had not been applied (OR=13.7, 95% CI: 5.6-33.6).

Conclusion:

Understanding the risk factors associated with T. annulata infection and regular infection monitoring could reduce infection rates and economic losses and is essential for the implementation of efficient control programs.

Population Genetic Analysis and Sub-Structuring of Theileria annulata in Sudan

Theileria annulata, which causes tropical theileriosis, is a major impediment to improving cattle production in Sudan. Tropical theileriosis disease is prevalent in the north and central regions of Sudan. Outbreaks of the disease have been observed outside the known endemic areas, in east and west regions of the country, due to changes in tick vector distribution and animal movement. A live schizont attenuated vaccination based on tissue culture technology has been developed to control the disease. The parasite in the field as well as the vaccine strain need to be genotyped before the vaccinations are practiced, in order to be able to monitor any breakthrough or breakdown, if any, after the deployment of the vaccine in the field. Nine microsatellite markers were used to genotype 246 field samples positive for T. annulata DNA and the vaccine strain. North and central populations have a higher multiplicity of infection than east and west populations. The examination of principal components showed two sub-structures with a mix of all four populations in both clusters and the vaccine strain used being aligned with left-lower cluster. Only the north population was in linkage equilibrium, while the other populations were in linkage disequilibrium, and linkage equilibrium was found when all samples were regarded as single population. The genetic identity of the vaccine and field samples was 0.62 with the north population and 0.39 with west population. Overall, genetic investigations of four T. annulata populations in Sudan revealed substantial intermixing, with only two groups exhibiting regional origin independence. In the four geographically distant regions analyzed, there was a high level of genetic variation within each population. The findings show that the live schizont attenuated vaccine, Atbara strain may be acceptable for use in all Sudanese regions where tropical theileriosis occurs.

Theileria annulata Subtelomere-Encoded Variable Secreted Protein-TA05575 Binds to Bovine RBMX2

Tropical theileriosis is the disease caused by tick-transmitted apicomplexan parasite Theileria annulata, which has ability to transform bovine leukocytes, including B cells, macrophage cells, and dendritic cells. The T. annulata transformed cells are characterized as uncontrolled proliferation and shared some cancer-like phenotypes. The mechanism of the transformation by T. annulata is still not understood well. In previous reports, the subtelomere-encoded variable secreted proteins (SVSP) of T. parva were considered to contribute to phenotypic changes of the host cell, but the role of SVSP of T. annulata in host-pathogen relationship remains unknown. In the present study, a member of SVSP family, TA05575 of T. annulata was selected as the target molecule to analyze its expression profiles in different life cycle stages of T. annulata by qPCR and investigate its subcellular distribution of different passages of T. annulata transformed cells using confocal experiments. From the results, the transcription level of TA05575 at schizont stage was significantly higher than the other two life stages of T. annulata, and the protein of TA05575 was mainly distributed in nucleus of T. annulata infected cells. In addition, the potential proteins of host cells interacting with TA05575 were screened by Yeast-two hybrid system. The results of Co-IP experiment confirmed that TA05575 interacted with RBMX2-like protein that participated in transcription regulation of cells. In addition, a novel BiFC assay and flow cytometry were carried out, and the results further revealed that TA05575-RBMX2-like pair was directly interacted in cell context. Moreover, this interacting pair was found to distribute in intracellular compartments of HEK293T cells by using confocal microscopy. The results of the present study suggest that TA05575 may contribute for cells transformation due its distribution. According to the function of RBMX2, the interaction of TA05575 and RMMX2-like will provide a new information to further understand the mechanisms of cells transformation by T. annulata.

Serological Survey and Molecular Characterization of Theileria annulata in Sicilian Cattle

Tropical theileriosis is a tick-borne disease caused by hemoprotozoan parasites with considerable veterinary and economic impact worldwide. Ticks transmitting the disease belong to the Haemaphysalis, Rhipicephalus, and Hyalomma genera. The Hyalomma genus is very common in Sicily (Italy) and represents the main Theileria annulata vector in the island. Data concerning the molecular epidemiology of this pathogen are missing in the region. In 2018-2019, blood and serum samples were collected from 480 cows in seven Sicilian farms from four different provinces. Seroprevalence in the farms ranged from 22% to 71%. Three farms were selected for molecular analysis consisting of real-time PCR targeting the almost complete 18S ribosomal RNA (rRNA). Four amplicons per farm were sequenced and phylogenetic analyses were carried out. The four sequences were identical within each farm and showed 92-99% identity with the other farms and with sequences from Genbank. According to the phylogenetic analysis, these three sequences and an additional one from a laboratory-cultured Theileria annulata strain obtained in 1999 belonged to a single T. annulata clade with good bootstrap support with other sequences from Italy, India, and Iran, indicating limited geographical and temporal genetic variability of the parasite. This study represents the first phylogenetic analysis of T. annulata in Sicily, which will be useful to improve the strategies for theileriosis control and prevention.

Tick Fauna and Associated Rickettsia, Theileria, and Babesia spp. in Domestic Animals in Sudan (North Kordofan and Kassala States)

Ticks and tick-borne diseases (TBDs) have a major economic impact on animal production worldwide. In the present study, 2410 ticks were collected from January to August 2017 from livestock and other domestic animals in North Kordofan and Kassala, Sudan, for species identification and investigation of Rickettsia spp. and piroplasms, either individually or as pools containing up to 10 ticks by molecular methods. In total, 13 tick species were identified by morphology and 16S rDNA sequencing. The most frequent tick species were Hyalomma impeltatum (24.90%), Rhipicephalus evertsi evertsi (18.84%), Amblyomma lepidum (16.06%), and Rhipicephalus camicasi (12.49%). A pan-Rickettsia real-time PCR revealed an overall minimum infection rate (MIR) with Rickettsia spp. of 5.64% (136 positive tick pools/2410 total ticks). Rickettsia africae and Rickettsia aeschlimannii were the most frequently identified species by sequencing. Furthermore, the following highly pathogenic livestock parasites were detected: Theileria annulata, Theileria lestoquardi, Theileria equi, and Babesia caballi. The present study documented Rhipicephalus afranicus as well as Rickettsia conorii israelensis, Rickettsia massiliae, and Babesia pecorum for the first time in Sudan. These findings are significant for the animal production sector as well as in terms of One Health, as the detected Rickettsia spp. can cause serious illness in humans.

Clinical Pathology, Immunopathology and Advanced Vaccine Technology in Bovine Theileriosis: A Review

Theileriosis is a blood piroplasmic disease that adversely affects the livestock industry, especially in tropical and sub-tropical countries. It is caused by haemoprotozoan of the Theileria genus, transmitted by hard ticks and which possesses a complex life cycle. The clinical course of the disease ranges from benign to lethal, but subclinical infections can occur depending on the infecting Theileria species. The main clinical and clinicopathological manifestations of acute disease include fever, lymphadenopathy, anorexia and severe loss of condition, conjunctivitis, and pale mucous membranes that are associated with Theileria-induced immune-mediated haemolytic anaemia and/or non-regenerative anaemia. Additionally, jaundice, increases in hepatic enzymes, and variable leukocyte count changes are seen. Theileria annulata and Theileria parva induce an incomplete transformation of lymphoid and myeloid cell lineages, and these cells possess certain phenotypes of cancer cells. Pathogenic genotypes of Theileria orientalis have been recently associated with severe production losses in Southeast Asia and some parts of Europe. The infection and treatment method (ITM) is currently used in the control and prevention of T. parva infection, and recombinant vaccines are still under evaluation. The use of gene gun immunization against T. parva infection has been recently evaluated. This review, therefore, provides an overview of the clinicopathological and immunopathological profiles of Theileria-infected cattle and focus on DNA vaccines consisting of plasmid DNA with genes of interest, molecular adjuvants, and chitosan as the most promising next-generation vaccine against bovine theileriosis.