Sequence heterogeneity in the 18S rRNA gene within Theileria equi and Babesia caballi from horses in South Africa (original) (raw)
Related papers
Sequence heterogeneity in the 18S rRNA gene in Theileria equi from horses presented in Switzerland
Veterinary Parasitology, 2016
A reverse line blot (RLB) hybridization assay was adapted and applied for equine blood samples collected at the animal hospital of the University of Zurich to determine the presence of piroplasms in horses in Switzerland. A total of 100 equine blood samples were included in the study. The V4 hypervariable region of the 18S rRNA gene was amplified by polymerase chain reaction and analyzed using the RLB assay. Samples from seven horses hybridized to a Theileria/Babesia genus-specific and a Theileria genusspecific probe. Of these, two hybridized also to the Theileria equi-specific probe. The other five positive samples did not hybridize to any of the species-specific probes, suggesting the presence of unrecognized Theileria variants or genotypes. The 18S rRNA gene of the latter five samples were sequenced and found to be closely related to T. equi isolated from horses in Spain (AY534822) and China (KF559357) (≥98.4% identity). Four of the seven horses that tested positive had a documented travel history (France, Italy, and Spain) or lived abroad (Hungary). The present study adds new insight into the presence and sequence heterogeneity of T. equi in Switzerland. The results prompt that species-specific probes must be designed in regions of the gene unique to T. equi. Of note, none of the seven positive horses were suspected of having Theileria infection at the time of presentation to the clinic. Clinicians should be aware of the possibility of equine piroplasma infections outside of endemic areas and in horses without signs of piroplasmosis.
2020
The aim of this study was to investigate equine piroplasms of wild horses (Equus ferus caballus) in Konya province of Turkey in November-December 2017. For this aim, blood samples were collected from 36 wild horses and examined for equine piroplasms by microscopy and multiplex PCR. Some of the PCR products from positive samples were also sequenced. Five (13.89%) out of the 36 horses were infected with either Theileria equi, Babesia caballi or both in the microscopical examination. Single infections with T. equi and B. caballi were detected in three (8.33%) and one horses (2.78%), respectively. Prevalence of T. equi, B. caballi and mix infections was determined as 50%, 38.8% and 38.8% by multiplex PCR, respectively. Multiplex PCR was found more sensitive than microscopical examination to detect the piroplasms of horses. The results of sequence analysis showed 99.25-100% and 98.23-99.59% nucleotide sequence identity to the previously reported T. equi and B. caballi 18S rRNA gene sequences, respectively. Consequently, the existence of equine piroplasmosis in wild horses was reported for the first time in Turkey, and high molecular prevalences of T. equi and B. caballi were reported with this study.
Molecular detection of Theileria species and Babesia caballi from horses in Nigeria
Parasitology Research
Equine piroplasmosis (EP) is an infectious, tick-borne disease caused by the hemoprotozoan parasites, Theileria equi, Babesia caballi, and a recently reported new species, T. haneyi. Infections by these apicomplexan parasites limit performance and cause economic losses for the horse industry. Equine piroplasmosis is widespread in the northern regions of Nigeria, where an increasing portion of the animal population is composed of horses. This disease has remained epidemiologically challenging, especially as the movement of horses increases across Nigeria. In this study, blood samples from 300 horses were collected in three states of northwestern Nigeria. The presence of piroplasms was screened by nested PCR targeting 18S rDNA and positive samples were analyzed using species-specific-nested PCR-targeting genes including ema1 (T. equi), rap1 (B. caballi), and a gene coding a protein of unknown function (T. haneyi). Species-specific-nPCR results demonstrated that the prevalence of T. equi was 13.0% (39/300), B. caballi was 3.3% (10/300) and T. haneyi was 2.7% (8/300). Mixed infections with T. equi and B. caballi was 2.7% (8/300) while T. equi, B. caballi, and T. haneyi multiple infection prevalence was 0.6% (2/300). We used 18S rDNA sequences to determine close relationships between T. equi by phylogenetic analysis and demonstrated that among 57 sequences of Theileria parasites, 28 samples belonged to clade A (49%), 13 samples were found to be clade C (22%), and 16 were clade D (28%). These results demonstrate the genetic diversity of T. equi circulating in horses from Nigeria.
Epidemiology and genetic diversity of Theileria equi and Babesia caballi in Mongolian horses
Infection, genetics and evolution, 2024
Equine piroplasmosis is a tick-borne disease caused by Theileria equi and Babesia caballi in horses. Because of its impact on horse industry, control of this disease is crucial for endemic countries. The control of equine piroplasmosis may be influenced by the genotypic diversity of T. equi and B. caballi. Mongolia, a country with a thriving livestock industry, is endemic for T. equi and B. caballi. However, nationwide epidemiological surveys have not been conducted to determine the current status of infections and genetic diversity of these two parasite species. Therefore, the objective of this research was to investigate the infection rates and genotypes of T. equi and B. caballi in horses across Mongolia. Blood samples were collected from 1353 horses in 15 of Mongolia's 21 provinces, and their DNAs were analyzed with T. equi- and B. caballi-specific PCR assays. Additionally, blood smears were prepared from 251 horses, stained with Giemsa, and examined under a light microscope to identify T. equi and B. caballi. The microscopy revealed that 30 (11.9%) and 4 (1.6%) of the 251 horses were positive for T. equi and B. caballi, respectively. By contrast, PCR assays detected the T. equi and B. caballi in 1058 (78.2%) and 62 (4.6%) horses, respectively. Phylogenetic analysis of 18S rRNA sequences from 42 randomly selected T. equi-positive DNA samples detected the genotypes A and E. On the other hand, the rap-1 sequences from 19 randomly selected B. caballi-positive DNA samples occurred in clades representing the genotypes A and B1, as well as in a distinct clade closely related to the genotype A. Our findings confirm the widespread occurrence of T. equi and B. caballi infections in Mongolian horses, highlighting the need for a comprehensive control approach.
equence heterogeneity in the 18 S rRNA gene in Theileria equi from orses presented in Switzerland
2016
A reverse line blot (RLB) hybridization assay was adapted and applied for equine blood samples collected at the animal hospital of the University of Zurich to determine the presence of piroplasms in horses in Switzerland. A total of 100 equine blood samples were included in the study. The V4 hypervariable region of the 18S rRNA gene was amplified by polymerase chain reaction and analyzed using the RLB assay. Samples from seven horses hybridized to a Theileria/Babesia genus-specific and a Theileria genusspecific probe. Of these, two hybridized also to the Theileria equi-specific probe. The other five positive samples did not hybridize to any of the species-specific probes, suggesting the presence of unrecognized Theileria variants or genotypes. The 18S rRNA gene of the latter five samples were sequenced and found to be closely related to T. equi isolated from horses in Spain (AY534822) and China (KF559357) (≥98.4% identity). Four of the seven horses that tested positive had a documen...
Journal of the Hellenic Veterinary Medical Society, 2021
Equine Piroplasmosis (EP) is a tick-borne disease caused by Theileria equi and Babesia caballi of the phylum Apicomplexa. In this study, 102 blood samples were randomly collected from the horses in Mus province of Turkey. PCR analysis, gene sequences, and phylogenetic analyses were carried out for detecting the presence and genotypic characteristics of species that cause piroplasmosis. Four (3.9%) of the 102 horses that were examined were found to be positive for T. equi, while B. caballi was not detected. Theileria equi isolates that were detected in the sequence analyses were found to be 100% identical to the isolates that were isolated from the horses in Turkey, the United States, and South Africa as well. In the phylogenetic analysis, all of the isolates were found to cluster with T. equi sequences in the genotype A. This study, in which we revealed intraspecies sequence heterogeneity of the parasite using the 18S rRNA gene region, provides important epidemiological data for equine piroplasmosis. However, we think that determining the characterization of genotypes that are common in different parts of our country is extremely important in terms of developing new diagnostic tools and vaccines.
Veterinary Parasitology, 2014
Equine piroplasmosis is the most important tick-borne disease of horses. Regulations on movement of horses into disease-free countries are in place to preserve international trade. Introduction of infectious disease, such as equine piroplasmosis, into non-endemic countries remains a substantial risk owing to the wide-spread distribution of vectors. Identification and restriction of movement of Theileria equi persistently infected horses is an integral part of control strategies, because persistently infected horses with low parasitaemia are an important reservoir. We used real-time PCR for diagnosis of T. equi DNA in clinically healthy horses in an equine piroplasmosis endemic area. The sensitivity was assessed using a synthetic plasmid DNA and a laboratory workflow was developed to maximise detection of persistently infected horses. The detection limit was 10 rDNA copies of the plasmid DNA. Assuming that each red blood cell contains a single T. equi genome the detection limit corresponded to 2.5 T. equi/l of total blood and parasitaemia as low as 2-3.8 × 10 −5 %. A laboratory workflow was developed and assessed on samples from Saudi Arabia. The laboratory workflow focused on samples returning no or single positive result in duplicate PCR. In total, we obtained 42% (59/141; 95% confidence interval: 33.85-50.15) T. equi positive samples, 26% (37/141) negative for T. equi samples. The remaining 45 samples were judged as suspect with no definitive diagnosis made. The Saudi Arabia's T. equi small subunit ribosomal DNA (SSU rDNA) sequencing (n = 16) demonstrated A clade (n = 15) as the dominant T. equi clade. Clade B was sequenced in a single case. We present an approach for diagnostic workflow to detect T. equi in clinically healthy but persistently infected horses. Results from Saudi Arabia confirm that T. equi is widespread in the Middle East region. High proportion of horses with low parasitaemia calls for caution with results based on a single blood sample. Understating of the fluctuation of the parasitaema in persistently infected horses in endemic areas is needed to establish the required sample numbers for reliable detection of T. equi.
Folia Veterinaria, 2020
Equine theileriosis, an apicomplexan debilitating tick-borne parasitic disease of horses has caused considerable havoc to equine production all over the world. There is a dearth of information on the molecular characteristic of the parasites, Theileria equi Laveran, 1901, in Nigeria. Thus, in this study microscopy techniques and PCR were used to detect the T. equi of horses in Ogun, Oyo and Lagos States of Nigeria. We also characterized the partial region of 18S ribosomal RNA gene by sequencing and sequences analysis. One hundred and two horses consisting of Argentine 34 (33.3 %), Sudanese 21 (20.6 %) and local breeds 47 (46.1 %) including 2 females and 100 males were randomly sampled from the Polo Clubs in Ibadan, Lagos and from privately owned horse stables in Abeokuta. Blood samples were collected from the jugular vein, thin smears were prepared and stained with a field stain. The DNA was extracted from the blood and a partial region of the 18S ribosomal RNA gene was amplified. T...
Ticks and Tick-borne Diseases, 2016
Babesia caballi and Theileria equi are tick-borne pathogens, etiological agents of equine piroplasmosis that affect different species of Equidae causing relevantly important direct and indirect losses. A field study was conducted to evaluate the distribution of the equine piroplasms in an area of Central-Southern Italy and to identify correlated risk factors. Serum samples of 673 asymptomatic horses were collected during spring-summer of 2013 to estimate the seroprevalence of the parasites within the study area using T. equi and B. caballi Antibody test kit (VMRD ® , Inc, Pullman, WA, USA). The 273 seropositive samples were subsequently tested by real time PCR to verify the presence of the genome of the piroplasms, indicative of the carrier status of the subjects. The variables chosen to identify which were the risk factors associated with the serological and PCR-positivity for each of the equine piroplasms were the following: gender, age, breed, access to pasture, altitude, land cover, climatic zone, soil type and province location (coastal/inland). The resulting overall seroprevalence for T. equi was 39.8% (268/673) and for B. caballi was 8.9% (60/673) while 70.3% of the PCR tested samples (185/263) were positive for T. equi and 10.3% (27/263) for B. caballi. The univariate and multiple logistic regression models were used to assess the association of the risk factors with the different outcomes. The risk factors found to be associated with T. equi seropositivity were gender, age, breed, access to pasture, land cover, soil type and province location, while those associated with PCR-positivity were age, soil type and province location. As the number of B. caballi seropositive subjects was limited, the multiple logistic regression model was performed only for the PCR-positive status, identifying climatic zone and soil type as the sole risk factors. In the study area, a major diffusion of T. equi, in terms of seroprevalence and PCR-positivity was present when compared to that of B. caballi, probably related to the cumulative effect of the lifelong infection of the former protozoan. The identification of risk factors relative to each piroplasm infection, specific to a study area, is important in the development and improvement of tailored control and prevention programmes aimed at containing health and economic consequences.