Molecular evidence of a new Babesia sp. in goats

Role of Rhipicephalus bursa larvae in transstadial transmission and endemicity of Babesia ovis in chronically infected sheep

Babesia ovis, transmitted by Rhipicephalus bursa ticks, is the causative agent of ovine babesiosis, a disease characterized by fever, anemia, hemoglobinuria, and high mortality in sheep. This study investigates whether sheep that survived babesiosis without treatment can serve as a source of infection for B. ovis-free host-seeking R. bursa larvae in a later season. Three donor sheep were experimentally infected with B. ovis, and after six months, persistence of B. ovis was assessed through blood and tick transmission experiments. Blood from donor sheep was intravenously injected into three recipient sheep, while donor sheep were also infested with B. ovis-free R. bursa larvae. Engorged nymphs molted to adults, and new recipient sheep were infested with these ticks. All recipient sheep were monitored for B. ovis for 100 days using microscopic, serological, and molecular approaches. The presence of B. ovis was confirmed in the recipient sheep that received blood, leading to clinical infection in two. However, no B. ovis was detected in recipient sheep infested with ticks. These results suggest that sheep recovering from B. ovis infection do not serve as a source of infection for R. bursa larvae in subsequent seasons.

Incompetence of Vector Capacity of Rhipicephalus bursa to Transmit Babesia aktasi following Feeding on Clinically Infected Goat with High Level of Parasitemia

A recent molecular survey revealed a high prevalence of Babesia aktasi in indigenous goats from the Mediterranean region of Türkiye, coinciding with heavy Rhipicephalus bursa infestations. This geographical overlap has raised the possibility that R. bursa may serve as a vector for the parasite. To evaluate the potential of R. bursa to serve as a vector for the parasite, an experimental study was conducted in indigenous goats. An immune-suppressed donor goat was intravenously injected with 15 mL of the cryopreserved B. aktasi stabilate, resulting in severe clinical babesiosis and parasitemia. Subsequently, R. bursa larvae and adults derived from Babesia-free laboratory colonies were allowed to feed on the infected donor goat. After oviposition, engorged female carcasses, representative engorged nymphs, unfed larvae, and adult pools were used for DNA extraction and PCR analysis. No PCR positivity was detected in any of the DNA samples, except for those with engorged female carcasses and nymphs. Three immune-suppressed recipient goats were infested with the unfed immature and mature ticks consuming the blood of a donor infected with B. aktasi. No clinical or parasitological findings were encountered in the recipient for 40 days post-infestation. These findings indicated that R. bursa was not a competent vector for B. aktasi.

Experimental infection of non-immunosuppressed and immunosuppressed goats reveals differential pathogenesis of Babesia aktasi n. sp

Babesiosis is an acute and persistent tick-borne disease caused by protozoan parasites of the genus Babesia. These hemoparasites affect vertebrates globally, resulting in symptoms such as high fever, anemia, jaundice, and even death. Advancements in molecular parasitology revealed new Babesia species/genotypes affecting sheep and goats, including Babesia aktasi n. sp., which is highly prevalent in goats from Turkiye's Mediterranean region. The objective of this study was to investigate the pathogenesis of B. aktasi infection in immunosuppressed (n=7) and non-immunosuppressed (n=6) goats. These animals were experimentally infected with fresh B. aktasi infected blood, and their clinical signs, hematological and serum biochemical parameters were monitored throughout the infection. The presence of parasites in the blood of immunosuppressed goats was detected by microscopic examination between 4 and 6 days after infection, accompanied by fever and increasing parasitemia. Goats that succumbed acute disease exhibited severe clinical signs, such as anemia, hemoglobinuria, and loss of appetite. However, the goats that survived showed milder clinical signs. In the non-immunosuppressed group, piroplasm forms of B. aktasi were observed in the blood within 2-5 days after inoculation, but with low (0.01-0.2%) parasitemia. Although these goats showed loss of appetite, typical signs of babesiosis were absent except for increased body temperature. Hematological analysis revealed significant decreases in the levels of red blood cells, leukocytes and platelet values post-infection in immunosuppressed goats, while no significant hematological changes were observed in non-immunosuppressed goats. In addition, serum biochemical analysis showed elevated transaminase liver enzymes levels, decreased glucose, and lower total protein values in the immunosuppressed group post-infection. Babesia aktasi, caused mild disease with minor clinical symptoms in non-immunosuppressed goats. However, in immunosuppressed goats, it exhibited remarkable pathogenicity, leading to severe clinical infections and death. In conclusion, this study provides valuable insights into the pathogenicity of the parasite and will serve as a foundation for future research aimed at developing effective prevention and control strategies against babesiosis in small ruminants. Further research is required to investigate the pathogenicity of B. aktasi in various goat breeds, other potential hosts, the vector ticks involved, and its presence in natural reservoirs.

First Molecular Evidence of Babesia vogeli, Babesia vulpes, and Theileria ovis in Dogs from Kyrgyzstan

Tick-borne parasitic diseases cause mild to severe infections among vertebrate hosts, including dogs. Species in the genus Babesia are important tick-borne pathogens and have worldwide distributions. Although there are data on the prevalence and distribution of Babesia species among dogs around the world, there is no information available in Kyrgyzstan, according to a literature review. In this study, 337 dogs were screened by nested PCR for the presence of the 18S small subunit ribosomal RNA (18S SSU rRNA) gene of piroplasm species. Overall prevalence was 6.23% (21/337) for Babesia/Theileria spp. DNA sequencing of positively tested samples revealed that eighteen samples were infected with Babesia vogeli (B. vogeli) (5.34%), two samples with B. vulpes (0.59%), and one sample with Theileria ovis (T. ovis) (0.29%). The phylogenetic analyses and nucleotide sequences in contrast with those present in GenBank revealed that two nucleotide substitutions (594th and 627th) were found between B. vogeli isolates, including ours, indicating that the mutation is relatively rare. The sequences of other pathogens obtained in this study confirmed 100% nucleotide identity with B. vulpes and T. ovis sequences in GenBank. To the best of our knowledge, B. vogeli, B. vulpes, and T. ovis were detected for the first time in dogs from Kyrgyzstan, and it is thought that results will contribute to the understanding of the epidemiology of canine tick-borne pathogens in the country.

Global haplotype distribution of Babesia ovis inferred by 18S rRNA sequences; a phylogeographical systematic review

The genetic variability of apicomplexan parasite Babesia species is a principal strategy used by piroplasma to evade their hosts' immune responses. The purpose of this review was to evaluate our current knowledge on global haplotype distribution and phylogeography of Babesia ovis derived from sheep, goat, horse and ixodid (hard) ticks. Bibliographic English databases were searched from 2017 to 2023, identifying a total of 11 publications. The 18S ribosomal RNA (18S rRNA) sequences of B. ovis from Asia, Europe, and Africa were retrieved and subjected to estimate the genetic diversity and phylogenetic assessment. A haplotype network indicated a total of 29 haplotypes being classified into two distinct geographical haplogroups I and II including Nigeria and Uganda-derived B. ovis isolates. A moderately high level of genetic diversity was characterized in sheep/tick-derived B. ovis isolates originating from Iraq (Haplotype diversity: 0.781) and Turkey (Hd: 0.841). Based on the cladistic phylogenetic tree, two geographically different lineages of A and B were genetically differentiated except for Turkish isolates, indicating haplotype migration occurred between various geographical clades. In addition, the topology of UPGMA tree indicated that B. ovis population has a distinct clade compared to the rest clades of ovine babesiosis (B. crassa and B. motasi). The present results strengthen our knowledge to evaluate the evolutionary paradigms and transmission dynamics of B. ovis in different regions of the world; also it will provide groundwork for public health policy to control ovine babesiosis.

Molecular detection of Babesia and Theileria species/genotypes in sheep and ixodid ticks in Erzurum, Northeastern Turkey: First report of Babesia canis in sheep

Piroplasmosis is a tick-borne protozoan disease caused by Babesia and Theileria species in ruminants. This study sought to determine the presence and prevalence of the agents causing piroplasmosis among sheep in Erzurum province, Turkey. It also sought to identify the tick species infesting the sheep and investigate the possible role of the ticks in the transmission of piroplasmosis. A total of 1621 blood samples and 1696 ixodid ticks from infested sheep were collected. Each blood sample and 115 tick pools were subjected to PCR assay. A total of 307 blood samples were found to be positive for Babesia spp. and Theileria spp. according to molecular analysis. The sequence analysis was revealed the presence of B. ovis (0.4%), B. crassa (0.4%), B. canis (0.4%), T. ovis (69.3%), Theileria sp. (26.6%), and Theileria sp. OT3 (2.9%) in 244 samples. The collected ticks were identified as D. marginatus (62.5%), Hae. parva (36.2%), Hae. punctata (1.1%), Rh. turanicus (0.1%), and H. marginatum (0.1%). The molecular analysis of the adult tick samples revealed T. ovis and T. annulata positivity in the D. marginatus pools, B. crassa and T. ovis positivity in the Hae. parva pools, and T. ovis positivity in the Hae. punctata pools. These results provide up-to-date data concerning tick-borne protozoan diseases of sheep and tick species infesting sheep in the region. The sheep breeding industry is an important livelihood for the region so it is essential to perform repeated studies on these pathogens in order to prevent disruptions to animal husbandry.

Small Ruminant Piroplasmosis: High Prevalence of Babesia aktasi n. sp. in Goats in Türkiye

Small ruminant piroplasmosis is the hemoparasitic infection of sheep and goats caused by Babesia and Theileria species responsible for clinical infections with high mortality outcomes. The disease is transmitted by ixodid ticks and prevalent in the tropical and subtropical regions of the world, including Türkiye. A prevalence survey, using molecular methods, is conducted in this study to determine the frequency of newly defined Babesia aktasi n. sp. and other tick-borne piroplasm species in small ruminants in Turkiye. A total of 640 blood samples from sheep (n = 137) and goats (n = 503) were analyzed by nested PCR-based reverse line blot (RLB) hybridization. The results show that 32.3% (207/640) of apparently healthy, small ruminants are infected with three Theileria and two Babesia species. Babesia aktasi n. sp. was the most prevalent species in goats, with 22.5% of samples being positive, followed by B. ovis (4%), T. ovis (2.8%), T. annulata (2.6%), and Theileria sp. (0.6%). None of the sheep samples were positive for Babesia aktasi n. sp.; however, 51.8% were infected with T. ovis. In conclusion, the findings reveal that B. aktasi n. sp. is highly prevalent in goats, but absent in sheep. In future studies, experimental infections will determine whether B. aktasi n. sp. is infectious to sheep, as well as its pathogenicity in small ruminants.

Discovery of a Novel Species Infecting Goats: Morphological and Molecular Characterization of Babesia aktasi n. sp

A novel Babesia sp. infecting goats was discovered based on the molecular findings obtained in the current study, which was conducted in the Mediterranean region of Türkiye. The goal of this study was to isolate this species of Babesia (Babesia sp.) infecting goats in vivo and to assess the genetic and morphological characterization of the parasite. To identify the animal naturally infected with Babesia sp. and isolate the parasite from this animal, field studies were conducted first, and genomic DNA were extracted from blood samples taken from goats (n = 50). The Theileria, Babesia, and Anaplasma species were identified using a nested PCR-based reverse line blotting (RLB) method. The study included one goat that was determined to be infected with Babesia sp. (single infection) in RLB for in vivo isolation. A blood smear was prepared to examine the parasite's morphology, but it was found to be negative microscopically. Following that, a splenectomy operation (to suppress the immune system) was performed to make the parasites visible microscopically in this animal. Parasitemia began after splenectomy, and the maximum parasitemia was determined to be 1.9%. The goat displayed no significant symptoms other than fever, loss of appetite, and depression. During a period when parasitemia was high, blood from this goat was inoculated into another splenectomized goat (Theileria-Babesia-Anaplasma-Mycoplasma spp. free). On the third day of inoculation, 10% parasitemia with high fever was detected in the goat, and on the fourth day, the goat was humanely euthanized due to severe acute babesiosis symptoms. Except for mild subcutaneous jaundice, no lesions were discovered during the necropsy. According to the microscopic measurement results, ring, double pyriform, spectacle-frame-like, and line forms were observed, and it was observed to be between 1.0-2.5 µm (1.38 ± 0.17 to 0.7 ± 0.21-all forms). A phylogenetic analysis and sequence comparison using the 18S rRNA and cox1 genes revealed that this species is distinct from the small ruminant Babesia species (18S rRNA 92-94%, cox1 79-80%) and has the highest similarity to Babesia sp. deer, which has been reported in deer. Furthermore, it was determined to resemble B. venatorum, B. divergens, Babesia sp. FR1 and Babesia sp. MO1 species, all of which are zoonotic. Additional research is needed to clarify the clinical status of this parasite in goats and other hosts (mountain goat, sheep, calf).

First Molecular Identification of Babesia, Theileria, and Anaplasma in Goats from the Philippines

Goats are key livestock animals and goat raising is an income-generating venture for smallholder farmers, supporting agricultural development in many parts of the world. However, goat production is often limited by various factors, such as tick-borne diseases. Goat piroplasmosis is a disease caused by apicomplexan parasites Babesia spp. and Theileria spp., while anaplasmosis is caused by bacterial Anaplasma spp. In the Philippines, the presence of Babesia, Theileria, and Anaplasma has not been reported in goats. In this study, DNA obtained from goats were molecularly screened for Babesia/Theileria and Anaplasma. Of 396, 77.02% (305/396) and 38.64% (153/396) were positive for piroplasma and Anaplasma using PCR assays targeting the 18S rRNA and 16S rRNA genes, respectively. Similarly, Babesia ovis was detected in six samples (1.52%). Representative Babesia/Theileria sequences shared 89.97–97.74% identity with each other and were most closely related to T. orientalis, T. annulata, and Theileria spp. Meanwhile, Anaplasma 16SrRNA sequences were related to A. odocoilei, A. platys, and A. phagocytophilum. This is the first molecular identification of B. ovis, Theileria spp., and Anaplasma spp. in goats from the Philippines.

A descriptive study of parasites detected in ticks of domestic animals in Lesotho

Ticks are medically important and significant vectors of diseases affecting livestock, humans, and companion animals than any other arthropod vectors. In the absence of information on the relationship of tick species and piroplasms parasites in Lesotho, the current study was aimed at detecting piroplasms parasites of economic importance from ticks of domestic animals. A total of 322 pooled tick DNA samples were subjected to PCR screening for the presence of piroplasms. The overall infection rate of piroplasms was 7% with Babesia bigemina at 3.4% (11/322), B. bovis 0.3% (1/322), B. ovis 2.8% (9/322) and 0.6% (2/322) for B. motasi. DNA extracted from the Lesotho Rhipicephalus decoloratus and R. evertsi evertsi tested positive for the presence of B. bigemina with a 15% and 3% infection rate, respectively. Otobius megnini tested positive for only B. bovis at a 12.5% infection rate. Rhipicephalus e. evertsi was the only tick species PCR positive for ovine babesiosis with 3.2% for B. ovis and 0.7% for B. motasi. Equine piroplasm (Theileria equi and B. caballi) and Theileria (T. parva and T. ovis) parasites were not detected in the current study. The PCR-positive samples were confirmed by direct sequencing of the product. This study is the first to report on a relationship of Babesia parasites with tick species in Lesotho and it is evident that vector-borne diseases are present in ticks of domestic animals in this country. Research findings in this study require a joint effort from both veterinary and medical sectors to unite and conduct more epidemiological studies of tick-borne diseases in both animals and humans and to also determine the role played by tick species in the transmission of the detected parasites in domestic animals of Lesotho. This information provides a baseline knowledge of important piroplasms parasites and raising awareness of their prevalence in Lesotho.

Development of a novel multiplex PCR assay for the detection and differentiation of Plasmodium caprae from Theileria luwenshuni and Babesia spp. in goats

Intraerythrocytic parasites are traditionally identified by the microscopic examination of Giemsa-stained blood smears. However, this method does not always allow for the identification of individual species in goat's RBCs. Moreover, its unreliability in detecting low levels of parasitemia makes it unsuitable for epidemiological investigations and leaves goat farms vulnerable to potential outbreaks. In the present study, a novel multiplex PCR (mPCR) targeting the cytochrome c oxidase subunit I (COI) gene was developed to detect and subsequently differentiate Plasmodium caprae, Theileria luwenshuni, and Babesia spp. The specificity of each primer set was assessed both in silico and with a panel of DNA samples from the hosts themselves and other goat hemoparasites. Amplicons generated from each pair of primers were 664, 555, and 320-bp for P. caprae, Babesia spp., and T. luwenshuni, respectively. These products were further confirmed by sequencing. Our novel mPCR reactions successfully demonstrated the accurate and simultaneous amplification of the three parasites' DNA samples. The current mPCR method showed no cross-amplification with unintended targets. The detection limit of the mPCR in this study was 10⁸ parasites' DNA copies per reaction. The current mPCR was able to detect the minimum parasitemia of approximately 0.001%, 0.000005%, 0.00001% for P. caprae, Babesia spp. and T. luwenshuni, respectively. The diagnostic specificity in the detection of P. caprae and T. luwenshuni ranged from 94.9 to 100 %. The mPCR was further applied to a collection of field blood samples from five provinces in Thailand to validate its reliability and applicability. The results demonstrated the successful detection of P. caprae, Babesia spp. and T. luwenshuni in goat samples with the same sensitivity levels as conventional PCR methods. This study also confirmed the presence of T. luwenshuni and Babesia spp. in Thai goats. The current mPCR method offers an alternative for the diagnosis of P. caprae, T. luwenshuni, and Babesia spp., either single or under co-infection conditions, and for large-scale surveillance.

Case of Babesia crassa-Like Infection, Slovenia, 2014

We report a case of Babesia crassa–like infection in an asplenic patient in Slovenia in 2014. We diagnosed the infection using microscopy, 18S rRNA sequencing, and serology and monitored parasitemia using digital PCR. With its increasing occurrence, babesiosis should be included in differential diagnoses for immunocompromised patients displaying fever.

Primary Tick-Borne Protozoan and Rickettsial Infections of Animals in Turkey

Parasitic diseases caused by ticks constitute a barrier on global animal production, mainly in tropical and subtropical regions. As a country with a temperate and subtropical climate, Turkey has topography, climate, and pasture resources, and these resources are suitable for animal breeding and parasite–host–vector relationships throughout the country. This geography restricts the regulations on animal movements in the southeastern and eastern Anatolia because of the close contact with the neighboring states. The livestock resources in Turkey are regulated by strong foundations. Almost 30% of the agriculture-based gross domestic product is provided by the livestock industry. Parasitic diseases arising from ticks are endemic in Turkey, and they have a significant impact on the economy and animal health, particularly for ruminants. The main and economically-important tick-borne diseases (TBDs) suffered by animals include theileriosis, babesiosis, hepatozoonosis, and cytauxzoonosis caused by protozoa, and anaplasmosis and ehrlichiosis caused by rickettsiae. The most common hemoprotozoan and rickettsial agents are Anaplasma marginale, Anaplasma ovis, Anaplasma phagocytophilum, Anaplasma platys, Babesia bigemina, Babesia caballi, Babesia ovis, Cytauxzoon felis, Ehrlichia canis, Hepatozoon canis, Theileria annulata and Theileria equi. These diseases are basically controlled through treatment and measures for tick control. Vaccination can be performed for only tropical theileriosis caused in Turkey. We reviewed the studies published in domestic and international journals to gather epidemiological data regarding the major TBDs suffered by animals in Turkey.

Challenges in Tick-Borne Pathogen Detection: The Case for Babesia spp. Identification in the Tick Vector

The causative agents of Babesiosis are intraerythrocytic protozoa of the genus Babesia. Babesia parasites are present around the world, affecting several mammals including humans, pets and livestock, hence its medical and veterinary relevance. Babesia spp. detection in its invertebrate host is a main point in understanding the biology of the parasite to acquire more knowledge on the host–Babesia–vector interactions, as increasing knowledge of the Babesia lifecycle and babesiosis epidemiology can help prevent babesiosis outbreaks in susceptible mammals. The aim of the present review is to highlight the newest findings in this field, based on a bibliographic compilation of research studies recently carried out for the detection of the main Babesia species found in tick vectors affecting mammalian hosts, including the different tick stages such as adult ticks, larvae, nymphs and eggs, as well as the detection method implemented: microscopic tools for parasite identification and molecular tools for parasite DNA detection by conventional PCR, nested-PCR, PCR-RFLP, PCR-RLB hybridization, real time-PCR, LAMP and RAP assays. Although molecular identification of Babesia parasites has been achieved in several tick species and tissue samples, it is still necessary to carry out transmission experiments through biological models to confirm the vectorial capacity of various tick species.

Bovine Babesiosis in Turkey: Impact, Current Gaps, and Opportunities for Intervention

Bovine babesiosis is a global tick-borne disease that causes important cattle losses and has potential zoonotic implications. The impact of bovine babesiosis in Turkey remains poorly characterized, but several Babesia spp., including B. bovis, B. bigemina, and B. divergens, among others and competent tick vectors, except Rhipicephalus microplus, have been recently identified in the country. Bovine babesiosis has been reported in all provinces but is more prevalent in central and highly humid areas in low and medium altitude regions of the country housing approximately 70% of the cattle population. Current control measures include acaricides and babesicidal drugs, but not live vaccines. Despite the perceived relevant impact of bovine babesiosis in Turkey, basic research programs focused on developing in vitro cultures of parasites, point-of-care diagnostic methods, vaccine development, “omics” analysis, and gene manipulation techniques of local Babesia strains are scarce. Additionally, no effective and coordinated control efforts managed by a central animal health authority have been established to date. Development of state-of-the-art research programs in bovine babesiosis to address current gaps in knowledge and implementation of long-term plans to control the disease will surely result in important economic, nutritional, and public health benefits for the country and the region.

Molecular detection and phylogeny of Anaplasma spp. in cattle reveals the presence of novel strains closely related to A. phagocytophilum in Turkey

Anaplasma species are obligate intracellular rickettsial pathogens that affect the health of humans and animals. In this study, we investigated the presence and frequency of Anaplasma species by 16S rRNA PCR-RLB, RFLP, and DNA sequencing in 200 apparently healthy cattle. Anaplasma spp. overall infection rate was 38.5 % (77/200) by RLB. The frequency of single and mixed infections was 31.5 % (63/200) and 7% (14/200), respectively. The most common species was A. marginale (32.5 %), followed by A. centrale (5.5 %), Anaplasma/Ehrlichia catc-all (5.5 %) and Anaplasma sp. Omatjenne (2.5 %). No A. phagocytophilum and A. bovis were detected in the tested animals. Eleven of 77 PCR-positive amplicons gave positive reactions to the catch-all probes but did not show any signals to the species-specific probes, but PCR-RFLP results showed that these amplicons were A. phagocytophilum-like 1 and A. phagocytophilum-like 2 strains. Sequencing and phylogenetic analyses based on 16S rRNA gene validated RFLP findings and provided evidence for the circulation of A. phagocytophilum-like-1 and 2 strains in Turkish cattle. This is the first report of the presence of A. phagocytophilum-like strains in the country. These findings indicate that A. phagocytophilum-like 1 and 2 strains should be taken into account in the differential diagnosis with bovine anaplasmosis.

Insights into the phylogenetic relationships and drug targets of Babesia isolates infective to small ruminants from the mitochondrial genomes

Background

Babesiosis, a tick-borne disease caused by protozoans of the genus Babesia, is widespread in subtropical and tropical countries. Mitochondria are essential organelles that are responsible for energy transduction and metabolism, calcium homeostasis and cell signaling. Mitochondrial genomes could provide new insights to help elucidate and investigate the biological features, genetic evolution and classification of the protozoans. Nevertheless, there are limited data on the mitochondrial genomes of ovine Babesia spp. in China.

Methods

Herein, we sequenced, assembled and annotated the mitochondrial genomes of six ovine Babesia isolates; analyzed the genome size, gene content, genome structure and cytochrome b (cytb) amino acid sequences and performed comparative mitochondrial genomics and phylogenomic analyses among apicomplexan parasites.

Results

The mitochondrial genomes range from 5767 to 5946 bp in length with a linear form and contain three protein-encoding genes, cytochrome c oxidase subunit 1 (cox1), cytochrome c oxidase subunit 3 (cox3) and cytb, six large subunit rRNA genes (LSU) and two terminal inverted repeats (TIR) on both ends. The cytb gene sequence analysis indicated the binding site of anti-Babesia drugs that targeted the cytochrome bc1 complex. Babesia microti and Babesia rodhaini have a dual flip-flop inversion of 184–1082 bp, whereas other Babesia spp. and Theileria spp. have one pair of TIRs, 25–1563 bp. Phylogenetic analysis indicated that the six ovine Babesia isolates were divided into two clades, Babesia sp. and Babesia motasi. Babesia motasi isolates were further separated into two small clades (B. motasi Hebei/Ningxian and B. motasi Tianzhu/Lintan).

Conclusions

The data provided new insights into the taxonomic relationships and drug targets of apicomplexan parasites.

Molecular detection and genetic characteristics of Babesia gibsoni in dogs in Shaanxi Province, China

Background

Several members of genus Babesia are important pathogens causing babesiosis in dogs. In China, at least five Babesia species have been described in dogs or ticks. This study sought to determine the prevalence and molecular characteristics of various Babesia spp. in dogs in cities in Shaanxi Province in China, including Xi’an and Hanzhong.

Methods

A total of 371 blood samples were collected from pet dogs presenting to veterinary clinics in the cities of Xi’an and Hanzhong in Shaanxi, China. Babesia spp. DNA was detected via amplification of partial 18S rRNA genes by semi-nested PCR. Almost full-length 18S rRNA, ITS, partial TRAP and complete cytb genes were recovered for analysis of the genetic characteristics and relationships with known isolates.

Results

A single species, Babesia gibsoni, was identified in dogs in Xi’an and Hanzhong. Consistently, B. gibsoni was also detected in 14 ticks collected from positive dogs. Sequence similarities and phylogenetic analysis suggested that the isolates identified herein showed a closer genetic relationship with isolates from East Asian countries rather than India, Bangladesh, or the USA. Sequence analysis based on tandem repeat analysis of the TRAP gene further revealed that specific haplotypes were circulating in both Xi’an and Hanzhong, with no specific regionality. In addition, 10.9% of all isolates with atovaquone (ATV)-resistance were identified because of M121I mutation in the deduced cytb protein.

Conclusions

This study revealed a high prevalence rate of Babesia infection. Babesia gibsoni was the only Babesia species identified in cases of canine babesiosis in the cities of Xi’an and Hanzhong cities in Shaanxi, China. In addition, the TRAP gene presented high genetic diversity across isolates. Such information is useful for elucidating the epidemiological characteristics of canine babesiosis, as well as the overall genetic diversity of Babesia spp. circulating in dog populations in Shaanxi Province.

Molecular detection of small ruminant piroplasmosis and first report of Theileria luwenshuni (Apicomplexa: Theileridae) in small ruminants of Pakistan

Theileriosis is a widespread and economically important disease of small ruminants in Pakistan. Ruminants are the intermediate hosts in the lifecycle of Theileria spp., with ticks of the family Ixodidae being the definitive hosts. To better understand the distribution and prevalence of theileriosis in Pakistan, a molecular survey was performed in small ruminants from the Lower Dir district of the Khyber Pakhtunkhwa province. A total of 200 healthy sheep and goats were screened from Maidan, Samar Bagh and Munda districts of district Dir Lower, Pakistan during December (2017) to April (2018). DNA samples were screened through nested PCR using universal primers. The amplified 492-498 bp amplicon was subjected to RLB analysis which was based on the hypervariable of the 18S rRNA gene to test for the presence of genotypes of Theileria in blood samples. A phylogeny was constructed to determine the species of Theileria genotypes. Nested PCR results indicated 53.5% prevalence of one or more Theileria genotypes in the blood of the host animal. From RLB assay, 27 animals (13.5%) showed infection with only a single species of Theileria while 80 animals (40%) showed coinfection by multiple Theileria spp. Based on the 18S rRNA phylogeny, the unknown genotype is of the species Theileria luwenshuni and is closely related to Chinese isolates. The present finding is the first report on molecular diagnosis of Theileria luwenshuni in small ruminants in Pakistan.

Comparative analysis of apicoplast genomes of Babesia infective to small ruminants in China

Background

Babesiosis is an economically important disease caused by tick-borne apicomplexan protists of the genus Babesia. Most apicomplexan parasites, including Babesia, have a plastid-derived organelle termed an apicoplast, which is involved in critical metabolic pathways such as fatty acid, iron-sulphur, haem and isoprenoid biosynthesis. Apicoplast genomic data can provide significant information for understanding and exploring the biological features, taxonomic and evolutionary relationships of apicomplexan parasites, and identify targets for anti-parasitic drugs. However, there are limited data on the apicoplast genomes of Babesia species infective to small ruminants.

Methods

PCR primers were designed based on the previously reported apicoplast genome sequences of Babesia motasi Lintan and Babesia sp. Xinjiang using Illumina technology. The overlapped apicoplast genomic fragments of six ovine Babesia isolates were amplified and sequenced using the Sanger dideoxy chain-termination method. The full-length sequences of the apicoplast genomes were assembled and annotated using bioinformatics software. The gene contents and order of apicoplast genomes obtained in this study were defined and compared with those of other apicomplexan parasites. Phylogenetic trees were constructed on the concatenated amino acid sequences of 13 gene products using MEGA v.6.06.

Results

The results showed that the six ovine Babesia apicoplast genomes consisted of circular DNA. The genome sizes were 29,916–30,846 bp with 78.7–81.0% A + T content, 29–31 open reading frames (ORF) and 23–24 transport RNAs. The ORFs encoded four DNA-directed RNA polymerase subunits (rpoB, rpoCl, rpoC2a and rpoC2b), 13 ribosomal proteins, one elongation factor TU (tufA), two ATP-dependent Clp proteases (ClpC) and 7–11 hypothetical proteins. Babesia sp. has three more genes than Babesia motasi (rpl5, rps8 and rpoB). Phylogenetic analysis showed that Babesia sp. is located in a separate clade. Babesia motasi Lintan/Tianzhu and B. motasi Ningxian/Hebei were divided into two subclades.

Conclusions

To our knowledge, this study is the first to elucidate the whole apicoplast genomic structural features of six Babesia isolates infective to small ruminants in China using Sanger sequencing. The data provide useful information confirming the taxonomic relationships of these parasites and identifying targets for anti-apicomplexan parasite drugs.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3581-x) contains supplementary material, which is available to authorized users.

A cross-sectional screening by next-generation sequencing reveals Rickettsia, Coxiella, Francisella, Borrelia, Babesia, Theileria and Hemolivia species in ticks from Anatolia

Background

Ticks participate as arthropod vectors in the transmission of pathogenic microorganisms to humans. Several tick-borne infections have reemerged, along with newly described agents of unexplored pathogenicity. In an attempt to expand current information on tick-associated bacteria and protozoans, we performed a cross-sectional screening of ticks, using next-generation sequencing. Ticks seeking hosts and infesting domestic animals were collected in four provinces across the Aegean, Mediterranean and Central Anatolia regions of Turkey and analyzed by commonly used procedures and platforms.

Results

Two hundred and eighty ticks comprising 10 species were evaluated in 40 pools. Contigs from tick-associated microorganisms were detected in 22 (55%) questing and 4 feeding (10%) tick pools, with multiple microorganisms identified in 12 pools. Rickettsia 16S ribosomal RNA gene, gltA, sca1 and ompA sequences were present in 7 pools (17.5%), comprising feeding Haemaphysalis parva and questing/hunting Rhipicephalus bursa, Rhipicephalus sanguineus (sensu lato) and Hyalomma marginatum specimens. A near-complete genome and conjugative plasmid of a Rickettsia hoogstraalii strain could be characterized in questing Ha. parva. Coxiella-like endosymbionts were identified in pools of questing (12/40) as well as feeding (4/40) ticks of the genera Rhipicephalus, Haemaphysalis and Hyalomma. Francisella-like endosymbionts were also detected in 22.5% (9/40) of the pools that comprise hunting Hyalomma ticks in 8 pools. Coxiella-like and Francisella-like endosymbionts formed phylogenetically distinct clusters associated with their tick hosts. Borrelia turcica was characterized in 5% (2/40) of the pools, comprising hunting Hyalomma aegyptium ticks. Co-infection of Coxiella-like endosymbiont and Babesia was noted in a questing R. sanguineus (s.l.) specimen. Furthermore, protozoan 18S rRNA gene sequences were detected in 4 pools of questing/hunting ticks (10%) and identified as Babesia ovis, Hemolivia mauritanica, Babesia and Theileria spp.

Conclusions

Our metagenomic approach enabled identification of diverse pathogenic and non-pathogenic microorganisms in questing and feeding ticks in Anatolia.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3277-7) contains supplementary material, which is available to authorized users.

Molecular Evidence for a Novel Species of Babesia in Unfed Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

This study reports a novel species of Babesia in unfed Rhipicephalus sanguineus sensu lato and its phylogenetic relationship to other species. One-hundred and forty DNA samples extracted from tick pools comprising 5,403 unfed R. sanguineus s.l. ticks were screened for Babesia. Overall Babesia infection was detected in female, male, and nymph pools with an infection rate maximum likelihood estimate (MLE) of 1.98 (CI 0.65-4.74), 0.50 (CI 0.03-2.40), and 0.07 (CI 0.01-0.21), respectively. Three adult female tick pools (MLE 1.44, CI 0.38-3.88) and one adult male pool (MLE 0.50, CI 0.03-2.40) hybridized to the catchall and Babesia genus probes but did not hybridize to any species-specific probe tested, suggesting the presence of an unidentified Babesia species. Phylogenetic analysis and sequencing revealed the newly detected Babesia isolate to form a clade distinct from fully identified canine, bovine, equine, and ovine Babesia species, with a range of 88.6-92.9% nucleotide identity.

Molecular characterization of Babesia species in wild animals and their ticks in Turkey

To date, no study has investigated Babesia ecology in wild boars, hares or foxes in Turkey. This study aimed to determine and characterize Babesia spp. in wild animals and their ticks. We identified a novel Babesia genotype and four known Babesia species in wild animals and their ticks. We detected Babesia spp. molecularly in hares for the first time. In addition, we identified B. vulpes in foxes for the first time in Turkey. The presence of B. rossi, B. crassa and B. occultans was also revealed in ticks collected from wild boars and hares. This is only the second report of B. rossi in ticks outside of Africa and suggests that B. rossi is circulating in ticks in Turkey. Therefore B. rossi poses a significant threat to domestic dogs. Here we demonstrate the role of wild animals in the life cycle of Babesia species in Turkey and contribute to Babesia ecological and taxonomic information.

A survey of canine haemoprotozoan parasites from Turkey, including molecular evidence of an unnamed Babesia

Canine tick-borne apicomplexan parasites have emerged in recent years, showing a wider geographic distribution and increased global prevalence. A reverse line blot assay was performed on 219 blood samples collected from domestic dogs for simultaneous detection of all named canine piroplasm species as well as Hepatozoon canis. Ten samples hybridized to the Theileria/Babesia and Babesia catch all probes but did not hybridize to any species-specific probe tested, suggesting the presence of an unrecognized Babesia species or genotype. Sequencing results showed 91.5%, 91.9%, 92.4%, 92.4%, and 89.2% similarity to B. canis, B. vogeli, B. rossi, B. gibsoni, and B. conradae, respectively. The highest homology (98.1-98.5%) observed was with unnamed Babesia sp. isolates (Ludhiana and Malbazar) described in dogs, Babesia sp. of buffalo origin, Babesia sp. Kashi 2, and Babesia orientalis, along with Babesia occultans of cattle origin. The partial cox1 sequence indicated that this isolate was most similar to Babesia sp. 1 HG-2012, with an identity of 86.5%. The survey revealed high prevalence of haemoprotozoans in domestic dogs (57.5%, CI 50.7-64.2), with Hepatozoon canis the most prevalent (54.3%, CI 47.5-61.117%), followed by Babesia sp. (4.6%, CI 2.2-8.2), B. vogeli (1.4%; CI 0.3-3.9), and B. canis (0.4%, CI 0-2.5). Combined infection of Hepatozoon canis and Babesia sp. was detected in five (2.3%, CI 0.7-5.2) samples and of H. canis and B. vogeli in two (0.9%, CI 0.1-3.2) dogs. The study contributes insight into the distribution and phylogenetic diversity of canine piroplasms in Turkey.