Molecular prevalence and phylogenetic analysis of Theileria annulata and Trypanosoma evansi in cattle in Northern Tunisia

Molecular epidemiology of bovine theileriosis and genetic diversity of Theileria annulata in three governorates of Egypt

Bovine theileriosis is a protozoan disease caused by the intracellular parasite (Theileria spp.) transmitted by ticks and it is considered one of the most significant parasitic diseases, potentially endangering Egyptian cattle herd industry. The present study was conducted for a molecular survey of bovine theileriosis and its associated risk factors (season variations, geographical locations, breeds, age, sex, tick infestation, and acaricide applications) in three Egyptian governorates, Beni-Suef, Al-Faiyum, and Al-Minya for a year extended from December 2021 to November 2022, in addition, genetic diversity of Theileria isolates. A total of 961 cattle were examined for Theileria infection clinically, microscopically, and by Polymerase Chain Reaction (PCR) using 18S rRNA gene for piroplasms DNA detection, Theileria genus-specific primers of the small subunit of rRNA gene, and Theileria annulata specific primers of the Tams-1 gene. The prevalence rate of bovine theileriosis was 9.26%, and 11.86% using Giemsa-stained blood smear and PCR, respectively. All positive samples screened by Theileria genus-specific primers were positive for T. annulata when screened by the specific primers. Based on molecular screening, season, cattle breeds and acaricide applications were considered risk factors for T. annulata infection, while locality, age, sex and tick infestation had insignificant effects with the occurrence of the disease. A potential novel T. annulata haplotype based on the Tam-1 gene was identified with accession numbers OR364144 and OR915851. Therefore, T. annulata was the only Theileria species found and played a significant problem in the cattle population. This study could be the basis for future studies on unexplored regions and different animal species for well-structured prevention and control measures.

Molecular detection and characterization of Theileria annulata, Babesia bovis, and Babesia bigemina infecting cattle and buffalo in southern Egypt

Tick-borne diseases have a major adverse effect on livestock worldwide, causing enormous economic losses in meat and milk production as well threatening animal and public health. In this study, we aimed to detect and characterize piroplasms isolated from cattle and buffalo in southern Egypt, using molecular techniques. Three hundred blood samples were collected from cattle and buffalo in two governorates in southern Egypt. All 300 samples (100%) were confirmed to contain DNA, as they exhibited bands of bovine β-actin gene at the expected 227 bp for cattle and buffalo. The samples were analyzed by PCR for the presence of piroplasms, specifically Babesia bovis, Babesia bigemina, and Theileria annulata. Samples positive for the piroplasma 18S ribosomal RNA gene were further examined for two additional genes, spherical body protein 4 gene, to provide an enhanced degree of specificity for the identification of B. bovis and B. bigemina, and the major merozoite surface antigen gene for T. annulata. The infection rate for piroplasma spp. was 60/300 (20%). The positivity rates were 10.7% (32/300) for T. annulata, 5.3% (16/300) for B. bovis, and 4% (12/300) for B. bigemina. By host species, 42/150 (28%) cattle and 18/150 (12%) buffalo were positive for piroplasms. None of the isolates sequenced for the B. bovis isolates from buffalo in this study showed 100% identity with any sequence deposited in GenBank for the small subunit ribosomal RNA gene (maximum identity value = 99.74%). Similarly, no T. annulata small subunit ribosomal RNA gene sequence identified in this study exhibited 100% identity with any sequence deposited in GenBank (maximum identity value = 99.89%). The current study provides a partial sequence of the T. annulata merozoite-piroplasm surface antigen gene, as well as the B. bovis and B. bigemina spherical body protein 4 genes, in cattle and buffalo in southern Egypt, and is the first report on these piroplasma genes in cattle and buffalo in southern Egypt.

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

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

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

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

Epidemiological situation of bovine tropical theileriosis in an arid region in central Tunisia with a phylogenetic analysis of Theileria annulata

BACKGROUND

Tropical theileriosis, Theileria annulata infection, is the most prevalent summer disease in Tunisia. It is transmitted by Hyalomma scupense, a two-host tick known to be endophilic.

OBJECTIVES

The present study aimed to estimate the infection prevalence of cattle by T. annulata in two districts from central Tunisia.

METHODS

Blood samples collected from 270 Holstein cattle from the Sidi Bouzid (140 samples) and Kasserine districts (130 samples) were analysed by Giemsa staining and T. annulata-specific PCR.

RESULTS

In both regions, PCR revealed a prevalence of 32.6%. This was significantly higher than the 6.3% prevalence obtained by Giemsa staining blood smears (p < 0.001). Giemsa staining also revealed a low parasitaemia of 0.05%. The PCR-based prevalence was not statistically different between the two districts (31.4 ± 0.04 and 33.8 ± 0.04% in Sidi Bouzid and Kasserine districts, respectively, p = 0.6). On the contrary, the results of blood smear examination (2.85 and 10% in Sidi Bouzid and Kasserine, respectively) differed significantly between the two sampling sites (p = 0.01). There was no evidence of a statistically significant difference between the overall molecular infection prevalence when the samples were segregated based on animals' age or gender (p = 0.1 and 0.2, respectively) and a similar trend was observed for Giemsa staining. Ten PCR amplicons of the Tams1 gene (721 bp) were subsequently sequenced from the two regions. The phylogenetic analyses showed 100% similarity between all sequences. The unique conserved Tams1 sequence was deposited in GenBank under the accession number OP428816 and used to infer its phylogenetic relationships with those available in the GenBank repository.

CONCLUSIONS

This is the first report of the presence of T. annulata in this region of central Tunisia which has no history of tropical theileriosis. Priority areas for future studies include understanding the origin of these T. annulata-positive animals in a region where the presence of a known natural vector tick, H. scupense, has not been reported. Given that the disease severely constrains cattle productivity, it would also be worthwhile to investigate if other potential vectors for T. annulata, such as Hyalomma dromedarii, are present in the arid regions.

Cattle co-infection patterns by hemopathogens and their phylogenetic analysis during the tick season in Constantine and Mila, Northeast Algeria

Tropical theileriosis, babesiosis, and anaplasmosis are the most dominant tick-borne infections in North Africa where they cause significant economic losses in ruminants' industry. The aim of the present work was to study infections and co-infection patterns in 66 cattle with clinical signs of piroplasmosis and/or anaplasmosis in two localities, Beni Hamidene and Grarem Gouga, districts of Constantine and Mila (Northeast of Algeria), respectively. This study was conducted between early May and late September during four years 2017, 2018, 2020, and 2021. PCR showed that the most frequent pathogen in cattle with clinical signs of piroplasmosis and/or anaplasmosis was Theileria annulata (66/66; 100%) followed by Babesia bovis (21/66; 31.8%), Anaplasma marginale (15/66; 22.7%), and Babesia bigemina (3/66; 4.5%) (p < 0.001). Giemsa-stained blood smears examinations revealed that 66.7% (44/66); 10.6% (7/66); and 9.1% (6/66) of cattle were infected by T. annulata, Babesia spp., and A. marginale, respectively (p < 0.001). PCR revealed seven co-infection patterns: T. annulata/A. marginale (15/66; 22.7%), T. annulata/B. bovis (21/66; 31.8%), T. annulata/B. bigemina (3/66; 4.5%), T. annulata/A. marginale/B. bovis (7/66; 10.6%), T. annulata/B. bovis/B. bigemina (2/66; 3%), T. annulata/A. marginale/B. bigemina (1/66; 1.5%), and T. annulata/A. marginale/B. bigemina/B. bovis (1/66; 1.5%). Phylogenetic analyses showed that T. annulata Tams1 and B. bigemina gp45 sequences were identical to isolates from Mauritania and South Africa, respectively. The three A. marginale amplicons obtained herein had 99.63 to 99.88% similarity between them. This study provides data that can be used to improve control programs targeting these cattle hemopathogens.

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.

Molecular epidemiology, associated risk factors, and phylogeny of Theileria annulata infecting buffaloes and cattle from different agro-climatic regions of Punjab, Pakistan

Background

Tropical theileriosis is the most prevalent hemoprotozoan disease in Pakistan.

Aims

The study aimed to investigate the epidemiology and evolutionary relationship of Theileria annulata in bovines in diverse agro-climatic regions of Punjab, Pakistan.

Methods

800 blood specimens were collected from asymptomatic cattle (n=480) and buffaloes (n=320) using a multistage sampling method from Sargodha (n=400) and Multan (n=400) districts. The samples were assessed for blood smear microscopy and cytochrome b gene based PCR. Twenty samples were collected from each union council of each district.

Results

The overall prevalence of T. annulata infection in bovines was 9% and 17.13% as determined by blood smear analysis and PCR, respectively. The disease positivity in cattle and buffaloes was respectively 10.21% and 20.42% by blood smear screening and 7.19%, 12.19% by PCR. The overall PCR based prevalence in the Sargodha and Multan districts was 19% and 15.25%, respectively. Absence of rural poultry, tick infestation, and a history of tick-borne diseases had significant effect in cattle. Tick infestation and age were the main statistically significant disease determinants in buffaloes. The evolutionary analysis of the cytochrome b gene showed that the Pakistani isolate infecting buffalo was related to those from Iran, India, Egypt, and Sudan. The isolate from cattle was genetically close to those from Pakistan, India, Iran, Iraq, and Turkey.

Conclusion

It can be concluded that biotic and abiotic factors contribute to disease occurrence. The current study will help to devise control strategies to prevent substantial economic losses.

Distribution of Tick-Borne Pathogens in Domestic Animals and Their Ticks in the Countries of the Mediterranean Basin between 2000 and 2021: A Systematic Review

Tick-borne pathogens (TBPs) include a wide range of bacteria, parasites and viruses that cause a large spectrum of animal, human and zoonotic tick-borne diseases (TBDs). The object of this review was to establish an inventory and an analysis of TBPs found in domestic animals in the countries of the Mediterranean Basin. This geographic area occupies a central position between several continents and is an area of movement for animals, humans and pathogens of interest and their vectors, which is important in terms of animal and human health. In this systematic review, we included a total of 271 publications produced between 2000–2021 concerning TBPs in domestic animals. Among this literature, we found a total of 90 pathogen species (known as TBPs) reported in the 20 countries of the area; these were detected in tick species from domestic animals and were also directly detected in domestic animals. In all, 31 tick species were recorded and 12 domestic animal species, the latter comprising nine livestock and three pet species. More than 50% of the publications were from Western Europe. Island data were extracted and assessed, as islands of the Mediterranean Basin were represented in 16% of the publications and 77.8% of the TBPs reported. Our results show the importance of islands in the monitoring of TBPs, despite the low percentage of publications.

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.

Genetic diversity in the Tams1 gene of Theileria annulata (Duschunkowsky and Luhs, 1904) infecting cattle

The present study describes the genetic diversity in the Tams1 gene (733 bp) of Theileria annulata along with the sequence, phylogenetic and haplotype analyses of the Indian isolates. The phylogenetic analyses displayed distinct clustering of the Indian isolates into three groups suggesting the presence of three genotypes, hitherto designated as T. annulata genotypes 1-3 (G1-G3). Genotype 3 seems to be novel containing only two newly generated sequences. Indian isolates displayed 88.4-100% and 82.2-100% similarity with each other at nucleotide (nt) and amino acid (aa) levels, respectively. However, the newly generated sequences (n = 36) showed 90.5-100% and 84.3-100% identity between them at nt and aa levels, respectively. The most diverse and heterogeneous genotype, G1, exhibited the highest number of polymorphic sites (S = 148), haplotypes (h = 16) and nucleotide differences (k = 43.23) besides haplotype (Hd = 0.903 ± 0.031) and nucleotide (π = 0.059 ± 0.005) diversities. Neutrality indices suggested a respective decrease and increase in population sizes of G1 and G2 genotypes in India. The nucleotide sequence analyses indicated the presence of extensive sequence variations between nucleotide positions 1-124, 194-257 and 396-494. The N-terminus of Tams1 protein displayed a considerable sequence variability with extensive variations in two regions, between amino acid positions 1-39 and 127-172, as compared to the conserved carboxyl terminus.

First survey of ticks, tick-borne pathogens (Theileria, Babesia, Anaplasma and Ehrlichia) and Trypanosoma evansi in protected areas for threatened wild ruminants in Tunisia

The aim of the study was to identify ticks present in the environment and wild Tunisian ruminants and to detect tick-borne pathogens and Trypanosoma evansi DNA in these specimens. Sampling was done throughout each season from the environment in three protected areas around Tunisia: El Feidja, Haddaj and Oued Dekouk. Ticks were collected also, from one fawn of Barbary red deer and eight naturally deceased wild ruminants (one Barbary red deer, five Scimitar-horned oryx, one Addax antelope and one Dorcas gazelle), all of which lived in various protected areas. PCR and nested PCRs were performed to detect the presence of Theileria spp., Babesia spp., Trypanosoma evansi, Ehrlichia spp., Anaplasma spp., Anaplasma bovis and Anaplasma phagocytophilum DNA in these tick specimens. A total of 352 ticks were collected, belonging to six different species: Hyalomma excavatum (80.6%), Hyalomma dromedarii (10.2%), Hyalomma marginatum (0.5%), Rhipicephalus bursa (0.5%), Rhipicephalus sanguineus sensu lato (5.1%) and Ixodes ricinus (2.8%). Pathogens have been detected in 25% of H. dromedarii, 9.1% of H. excavatum and 5% of R. sanguineus sensu lato. The percentage of detection of T. evansi was 0.2%. Ehrlichia spp.-Anaplasma spp. were detected in 10.1% of ticks. Anaplasma spp. and A. bovis were detected in 7.6%, and 0.8% of examined ticks, respectively. None of the Theileria spp., Babesia spp., or A. phagocytophilum DNA was detected in the tested ticks. To our knowledge, the present study represents the first identification of these six tick species and the first detection of rickettsial pathogens and T. evansi in North African wild ruminants' species. These results extend the knowledge about the diversity of ticks and tick-borne pathogens in wildlife and justify further investigations of the possible role of R. sanguineus sensu lato in the transmission of T. evansi.

Canine vector-borne protozoa: Molecular and serological investigation for Leishmania spp., Trypanosoma spp., Babesia spp., and Hepatozoon spp. in dogs from Northern Algeria

Dogs are competent reservoirs/hosts of several protozoan pathogens transmitted by blood-feeding arthropods. Throughout their long history of domestication, they have served as a link for the exchange of parasites among livestock, wildlife, and humans and therefore remain an important source of emerging and re-emerging diseases. In Algeria, while canine leishmaniosis (CanL) is well known to be endemic, no data are available on other vector-borne protozoans. Here, we investigate the occurrence and diversity of trypanosomes, piroplasms and Hepatozoon spp. and update the epidemiological status of CanL in dogs from Kabylia, northern Algeria. A total of 227 dogs from three regions of Kabylia were enrolled, including 77 dogs with clinical signs. Dogs were clinically examined and were tested for L. infantum antibodies using a Rapid Immuno-Migration (RIM™) and a quantitative indirect Immunofluorescence Antibody Test (IFAT). PCR screening and sequencing were performed for vector-borne protozoa. Sixty two percent (141/227) of dogs presented at least one infection, whereas 26% (59/227) were co-infected. L. infantum antibodies were detected in 35.7% (81/227) of dogs including 88.7% (68/77) of sick dogs. Molecular investigation revealed prevalence of: 6.6% (15/227), 13.2% (30/227), 41% (93/227) for Trypanosoma spp., B. vogeli and H. canis, respectively. T. evansi (3.1%) and potential new subspecies of T. congolense had been identified. Dog''s clinical status correlates positively with L. infantum antibody titers and the presence of co-infections. Susceptibility to CanL varied according to the dog's aptitude and guard dogs were more infected (51%) (P-value = .001). B. vogeli infection was more frequent in juveniles than adults (32% vs 9%, P-value < .001) and in females than males (21% vs 10%, P-value = .02). To the authors' knowledge, this is the first report on vector-borne protozoa infected dogs in Algeria. Current results are important not only for animal health, but also to avoid serious public health and livestock problems.