Molecular detection of Theileria species, Anaplasma species, Candidatus Mycoplasma haemobos, Trypanosoma evansi and first evidence of Theileria sinensis-associated bovine anaemia in crossbred Kedah-Kelantan x Brahman cattle

Genetic diversity and phylogeography of the global Theileria orientalis isolates inferred from MPSP gene sequences

BACKGROUND/OBJECTIVE

Theileria orientalis is a non-transforming Theileria species infecting cattle and water buffaloes. Several outbreaks of oriental theileriosis accompanied by considerable economic loss were documented in Asia, Australia, and New Zealand. The major piroplasm surface protein (MPSP) gene has frequently been used to molecularly characterize T. orientalis isolates worldwide. Various MPSP genotypes were detected with significant virulence variations. The present study provides the first in silico analysis for all globally published T. orientalis MPSP isolates to evaluate their phylogeny, diversity, and population structure.

METHODS

All studies that tested T. orientalis isolates using PCR-MPSP protocols were systematically collected from various databases. Theileria orientalis MPSP-sequenced isolates on the GenBank were collected and the sequences were tested for their phylogenetic relatedness, genetic diversity, recombination, natural selection, and population structure using various software.

RESULTS

The collected T. orientalis-MPSP isolates (n = 795) were clustered into 12 genotypes, including types 1 (Chitose), 2 (Ikeda), 3 (Buffeli), 4, 5, 7, 8, and N1-N5. The previously identified type 6 belonged to a separate species (Theileria sinensis). The previously identified type 9 was transferred to type 4. Two unidentified isolates from water buffaloes in India were clustered into a new suggested genotype "type N5". Of the 12 genotypes, Ikeda (type 2) is the most virulent in cattle. However, a few clinical cases have also been linked to types 1 (Chitose) and 7. In water buffaloes, T. orientalis outbreaks have been linked to genotypes N2 and N5. Geographic mapping of various genotypes revealed the dispersal of types 1 and 3 worldwide. Overall, the 795 isolates comprised 532 haplotypes and displayed very high nucleotide (π = 0.14) and haplotype (Hd = 0.995) diversities. As a result, a very low sequence conservation value (C = 0.207) was determined. The twelve genotypes displayed comparable haplotype diversities accompanied by statistically significant negative Tajima's D and Fu's Fs values suggesting population expansion. A high value for the minimum number of recombination events (Rm = 65) was estimated for the 795 isolates, and this value varied from 0 to 23 at the genotype level. Most types also displayed significant positive selection (dn/ds ratio > 1). This suggests that both recombination and positive selection occur in T. orientalis MPSP gene, which could explain the very high genetic diversity among various T. orientalis types. Different patterns were detected for the gene flow among T. orientalis populations from various hosts and geographies; however, there is evidence for the genetic relatedness between populations from neighbouring countries.

CONCLUSION

The high genetic polymorphism and different associated pathogenicity in T. orientalis-MPSP genotypes highlight the need for further investigations employing whole genome sequencing technology to provide accurate comparative gene-level analyses and help further understand their pathogenicity.

Detection of Theileria in cattle ticks (Rhipicephalus microplus) (Canestrini, 1888) in upper-northeastern Thailand

Theileria parasites were investigated from cattle ticks (Rhipicephalus microplus (Canestrini, 1888)) collected in 12 provinces in upper-northeastern Thailand based on the sequences of 18S rRNA and MPSP gene. Polymerase chain reactions (PCRs) and sequencing specific regions for the 18S rRNA gene revealed two species of Theileria pathogens; T. orientalis (n = 42) and T. sinensis (n = 31) with 94.50-100 % identity. In the provinces of upper-northeastern Thailand, the nucleotide diversity of Theileria's 18S rRNA for T. sinensis and T. orientalis were 0 % and 1.3 %. respectively. The MPSP gene was used to categorize the T. orientalis genotypes. The sequences were compared with those available in the public database (GenBank) for species identification. Phylogenetic trees of Theileria were constructed from the MPSP gene sequences of our amplicons and those available in GenBank using maximum-likelihood and neighbor-joining analyses. The results revealed three identified genotypes: type 3, 5, and 7. Although the main carriers of T. orientalis are ticks in the genus Haemaphysalis, T. orientalis was the most frequently found in R. microplus in upper-northeastern Thailand. Theileria was frequent in Nong Khai, Mukdahan, and Loei, three Thai provinces that bordered the Lao PDR close to the Mekong River. Epidemiological surveys and control strategies in this region should be considered.

Molecular detection of Anaplasma, Babesia, Theileria, and Trypanosoma infection in cattle and buffaloes in India

Tick-borne pathogens pose a significant global threat, causing substantial economic losses to the dairy industry. In India, tropical theileriosis, anaplasmosis, babesiosis, and trypanosomiasis are major hemo-parasitic diseases affecting bovines. A cross-sectional study was conducted to determine the prevalence of hemo-parasites in different farms in India. PCR assays were employed to detect carrier status, using gene targets msp1b, tams1, rap-1, ama1, and ITS1 for A. marginale, T. annulata, B. bovis, B. bigemina, and Trypanosoma species, respectively. Out of the 578 apparently healthy animals screened, 30.45% (95% CI: 26.84-34.32%) were infected with at least one hemo-parasite. Cattle showed an overall positivity of 32.87%, while buffaloes had a prevalence of 15.19%, which was statistically significant (p < 0.001). Interestingly, prevalence was higher in indigenous cattle (47.81%) compared to cross-breeds (25.53%) and exotics (14.62%), with a statistically significant difference (p < 0.001). The prevalence of hemo-parasites varied widely among the farms, ranging from 5.77 to 100%. A. marginale was the most prevalent parasite (23.70% of animals), followed by T. annulata (13.67%), Babesia species (1.90%), and Trypanosoma species (1.56%). Enzootic instability was observed in six of the eight farms, indicating a potential for future outbreaks. Co-infection was detected in 60 out of 176 animals positive for hemo-parasites, with 59 animals co-infected with A. marginale and T. annulata, and only one cross-breed cattle infected with both Anaplasma marginale and Babesia bigemina. The findings highlight the prevalence of hemo-parasites in farms, underscoring the need for whole-herd screening, treatment of infected animals, and improvement in farm management practices to prevent production losses caused by these pathogens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-024-01673-3.

Genetic Characterization of the RAP-1A and SBP-4 Genes of Babesia Species Infecting Cattle from Selangor, Malaysia, and Ribah, Nigeria

Bovine babesiosis has substantial economic implications in the cattle industry, emphasizing the need for a thorough understanding of the genetic diversity of the causative apicomplexan pathogen. Although babesiosis has been extensively studied globally, the genetic diversity of Babesia species in Malaysian and Nigerian cattle remains unreported. This study aims to bridge this gap by detecting and characterizing Babesia species in selected cattle herds. Our investigation explores the genetic diversity of Babesia species in cattle from Selangor, Malaysia, and Ribah, Nigeria. Blood samples revealed a 32.9% infection rate via PCR analysis. Further genetic analysis detected variations in Malaysian Babesia bigemina isolates but genetic similarity among Nigerian isolates. Conversely, all Babesia bovis isolates displayed genetic homogeneity. In summary, this research identifies genetic diversity in Babesia species affecting Malaysian and Nigerian cattle, highlighting regional disparities.

Preliminary study on prevalence of hemoprotozoan parasites harbored by Stomoxys (Diptera: Muscidae) and tabanid flies (Diptera: Tabanidae) in horse farms in Nakhon Si Thammarat province, Southern Thailand

Background and Aim

Stomoxys and tabanid flies are of medical and veterinary importance because they play crucial roles in disease transmission as mechanical vectors of various hemopathogens. However, its role as a hemoprotozoan parasite vector in horse farms has not been studied. Therefore, we investigated the occurrence of hemoprotozoan parasites belonging to the genera Babesia, Theileria, and Trypanosoma in Stomoxys and tabanid flies using conventional polymerase chain reaction (PCR) and DNA sequencing.

Materials and Methods

All samples (Stomoxys and tabanid flies) were collected using an Nzi trap for three consecutive days each month from November 2022 to March 2023. The flies were morphologically identified to the species level and separated according to sex. Individual (for tabanid flies) or pooled samples (consisting of three specimens of Stomoxys flies of the same species and sex collected from the same site) were used for DNA extraction. Conventional PCR was used to screen for hemoprotozoan parasite DNA, followed by Sanger sequencing to identify the species.

Results

In total, 189 biting flies were collected, including four species of Stomoxys (Stomoxys bengalensis, Stomoxys calcitrans, Stomoxys indicus, and Stomoxys sitiens) and five species of tabanids (Atylotus cryptotaxis, Chrysops dispar, Tabanus megalops, Tabanus mesogaeus, and Tabanus rubidus). Stomoxys calcitrans was the most prevalent species, accounting for 58.7% (n = 111) of the collected flies. Ten (12.4%) of the 81 samples (individuals and pools) analyzed by PCR were positive for the 18S rRNA gene of the Theileria/Babesia species. Trypanosoma DNA was not detected in any sample. After performing Basic Local Alignment Search Tool searches and a phylogenetic analysis, only six samples (7.4%), including S. calcitrans (n = 2), S. sitiens (n = 2), T. megalops (n = 1), and A. cryptotaxis (n = 1), were found to be infected with Theileria sinensis. Furthermore, apicomplexan parasites, namely, Mattesia spp. and Colpodella spp., were found on S. indicus, the fungus Meira spp. was found on S. calcitrans, and the pathogenic green alga Helicosporidium spp. was found on A. cryptotaxis.

Conclusion

This study is the first to report a variety of Stomoxys and tabanid flies collected from horse farms in Thailand, which were found to be infected with Theileria and Colpodella species that affect mammals, suggesting that Stomoxys and tabanid flies can be used to confirm the presence of hemoprotozoan parasites in the study area. Understanding the presence of hemoprotozoa in flies could help design vector control programs and manage various diseases in the study area.