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Topic:Theileria equi
Theileria equi is a protozoan parasite that infects horses, causing a disease known as equine piroplasmosis. This parasite is transmitted primarily through tick bites, with species such as Rhipicephalus and Dermacentor acting as vectors. The infection can lead to a range of clinical signs in horses, including fever, anemia, jaundice, and lethargy. Infected horses may also exhibit decreased performance and, in severe cases, death. Diagnosis of Theileria equi involves blood tests, including polymerase chain reaction (PCR) assays and serological methods, to detect the presence of the parasite or antibodies. This page compiles peer-reviewed research studies and scholarly articles that explore the transmission, pathogenesis, diagnosis, and management of Theileria equi in equine populations.
Persistently infected horses are reservoirs for intrastadial tick-borne transmission of the apicomplexan parasite Babesia equi. Tick-borne pathogens may be transmitted intrastadially and transstadially within a single vector generation as well as vertically between generations. Understanding the mode and relative efficiency of this transmission is required for infection control. In this study, we established that adult male Rhipicephalus microplus ticks efficiently acquire the protozoal pathogen Babesia equi during acute and persistent infections and transmit it intrastadially to naïve horses. Although the level of parasitemia during acquisition feeding affected the efficiency of the initial tick infection, infected t...
Investigation of seroprevalence of Theileria equi and Babesia caballi in horses in Nigde province, Turkey. The prevalence of equine piroplasmosis caused by Theileria equi and Babesia caballi in Nigde, in central Anatolia, Turkey has remained unknown. Serum samples were obtained from a total of 125 horses and were tested for antibodies to T. equi and B. caballi using the Indirect Fluorescence Antibody Test (IFAT). Twenty-three (18.4%) horses were seropositive for equine piroplasmosis. Anti-T. equi was observed in 16 horses (12.8%) while anti-B. caballi was detected in 12 horses (9.6%). In addition, 5 serum samples were positive for both parasites. The prevalence rates of antibodies to T. equi and B....
Estimation of the transmission dynamics of Theileria equi and Babesia caballi in horses. For the evaluation of the epidemiology of Theileria equi and Babesia caballi in a herd of 510 horses in SW Mongolia, several mathematical models of the transmission dynamics were constructed. Because the field data contain information on the presence of the parasite (determined by PCR) and the presence of antibodies (determined by IFAT), the models cater for maternal protection with antibodies, susceptible animals, infected animals and animals which have eliminated the parasite and also allow for age-dependent infection in susceptible animals. Maximum likelihood estimation procedures were used...
Serological evidence for Babesia canis infection of horses and an endemic focus of B. caballi in Hungary. In order to evaluate the seroconversion of horses to Babesia caballi and B. canis in Hungary, blood samples were collected from 371 animals on 23 different locations of the country. The presence of antibodies to B. caballi was screened with a competitive ELISA. All 29 positive samples came from one region (the Hortobágy). The prevalence of infection did not show correlation with sexes, and reached 100% in the age group of 2-5 years. Babesia canis-specific antibodies were demonstrated by IFAT in 6.74% of animals kept in 7 regions. The titres were low or medium level (1:40 to 1:160), indicating...
Seroprevalence of equine babesiosis in the Black Sea region of Turkey. The prevalence of Theileria equi and Babesia caballi was determined in equid blood samples in five provinces of the Black Sea region of Turkey by using the indirect fluorescent antibody test (IFAT). Of 153 samples, 53 (34.6%) and 33 (21.5%) were seropositive to B. caballi and T. equi, respectively. In addition, 8 (5.2%) of samples were seropositive to both T. equi and B. caballi. Anti T. equi and B. caballi antibodies were detected in all five regions. The prevalence of B. caballi was higher than T. equi in all counties. Antibodies to T. equi and B. caballi were detected in horses of all ages,...
Repeated high dose imidocarb dipropionate treatment did not eliminate Babesia caballi from naturally infected horses as determined by PCR-reverse line blot hybridization. Imidocarb treatment of horses infected with Babesia caballi is supposed to eliminate the infection, but data on the efficacy of this treatment is scarce. The study presented here concerns four Paso Fino horses, which were imported into the island of Curacao on the basis of a piroplasmosis negative complement fixation test (CFT). Upon re-testing with an indirect fluorescent antibody test immediately after arrival in Curacao, two horses appeared to have antibodies to B. caballi and all horses had antibodies to Theileria equi. Subsequent testing with polymerase chain reaction combined with a reve...
Diagnostic real-time PCR assay for the quantitative detection of Theileria equi from equine blood samples. We developed a TaqMan real-time polymerase chain reaction (PCR) assay for the quantitative detection of Theileria equi from the in vitro-cultured parasite and field blood samples collected from horses living in Ghana and Brazil. The detection limit for the assay was determined to be 1.5 parasites/microl per sample, and the quantitative capacity was demonstrated using the in vitro-cultured parasite. For field applications, the real-time PCR assay was compared to a previously established nested PCR assay used as the gold standard for the real-time PCR assay. Of 65 field blood samples, 46 samples...
Comparison of polymerase chain reaction methods for the detection of Theileria equi infection using whole blood compared with pre-extracted DNA samples as PCR templates. Rapid, efficient, and reproducible procedures for isolating DNA before PCR gene amplification are essential for the diagnosis of piroplasms. In this study, we evaluated the ease and reliability of detecting Theileria equi by PCR using pre-extracted DNA samples (by QIAamp DNA Mini Kit and phenol-chloroform methods) compared with blood spotted on FTA cards as PCR templates. Although minimal variations in limit of detection were observed among the methods compared, overall, the use of pre-extracted DNA samples and blood spotted on FTA cards had comparable detection limits. These results indicate ...
Passive transfer of Theileria equi antibodies to neonate foals of immune tolerant mares. Equine babesiosis, a tick transmitted haemoprotozoan disease caused by Theileria equi is globally distributed and responsible for heavy economic losses to the equine husbandry. Equids reared in endemic areas usually pick up infection at an early age and become immune tolerant throughout their life span. We studied the level of passively transferred antibodies in neonate foals born from pre-immuned mares. Latently T. equi infected pre-immuned pony and donkey mares (three each) were selected and T. equi antibody titres in neonates was monitored till 90 days post foaling (DPF) by applying Dot-ELI...
Detection of Babesia (Theileria) equi (Laveran, 1901) in horses in the Kars province of Turkey. This study was carried out in order to detect antibodies to Babesia (Theileria) equi in the local breed of horses in the province of Kars, Turkey. A total of 108 serum samples from apparently healthy horses in eight villages were examined for B. equi antibodies by an indirect immunofluorescent antibody test (IFAT). Of the 108 samples tested, 27 (25%) were found to be seropositive. The horses sampled in Aydinalan village had the highest prevalence (50.0%) of Babesia equi infection while the lowest prevalence was found among horses from Bayraktar village (12.5%). Statistically significant differ...
Validation of the indirect fluorescent antibody and the complement fixation tests for the diagnosis of Theileria equi. The indirect fluorescent antibody (IFA) test for Theileria equi was evaluated to assess test's suitability for the serological diagnosis of equine piroplasmosis, to provide performance parameters for the purpose of test validation, and to compare it with the complement fixation (CF) test. Using a protocol that included Evan's blue, the specificity of the IFA test was estimated at 99.0% for T. equi by the classical method of analysis, and 96.6% by the Bayesian method. The use of Evan's blue in the test protocol increased test specificity and contributed to an excellent test agreement between tw...
Molecular evidence for transplacental transmission of Theileria equi from carrier mares to their apparently healthy foals. The intra-erythrocytic parasite Theileria equi is one of two tick-transmitted causative agents of equine piroplasmosis. Piroplasms of T. equi can be transmitted across the equine placenta and once a horse is infected, it appears to remain a lifelong carrier, since anti-theilerial drugs suppress but do not eliminate the parasite. Carrier mares may transmit the organism to their offspring and this may result in abortion or neonatal piroplasmosis, but observations by some researchers suggest that foals may be born as carriers yet remain apparently healthy. Using a T. equi-specific oligonucleotide...
[Detection of Babesia caballi (Nuttall, 1910) and Theileria equi (Syn. Babesia equi , Laveran, 1901) by the polymerase chain reaction (PCR) in show and sport horses in the region of Ankara]. The aim of this study was to compare the diagnosis of Babesia caballi and Theileria equi by the polymerase chain reaction (PCR) and microscopic examination of blood specimens collected from show and sport horses in the region of Ankara in 2004. The blood specimens were collected from randomly selected 200 show and sport horses in the region of Ankara during the tick season as well as before and after the tick season for PCR testing. At the same time, Giemsa stained peripheral blood smears were examined for the presence of Babesia spp. and also the horses were examined for the presence of ticks...
Pathologic findings in reintroduced Przewalski’s horses (Equus caballus przewalskii) in southwestern Mongolia. The Przewalski's horse (Equus caballus przewalskii) was extinct in the wild by the mid 1960s. The species has survived because of captive breeding only. The Takhin Tal reintroduction project is run by the International Takhi Group; it is one of two projects reintroducing horses to the wild in Mongolia. In 1997 the first harem group was released. The first foals were successfully raised in the wild in 1999. Currently, 63 Przewalski's horses live in Takhin Tal. Little information exists on causes of mortality before the implementation of a disease-monitoring program in 1998. Since 1999, all dead...
Age-dependent dynamics of Theileria equi and Babesia caballi infections in southwest Mongolia based on IFAT and/or PCR prevalence data from domestic horses and ticks. Epidemiological factors of tick-borne equine piroplasmoses, caused by Theileria equi and Babesia caballi, were investigated using logistic regression (GLM) and general additive models (GAM) based on the prevalences determined in 510 domestic horses and in ticks in S.W. Mongolia by indirect immunofluorescence antibody test (IFAT) and/or multiplex PCR. Prevalences of T. equi and B. caballi in horses were 66.5% (95% CI: 62.1-70.7) and 19.1% (15.6-22.9), respectively by PCR and 78.8% (74.9-82.3) and 65.7% (61.3-69.9) by IFAT. Of 166 ticks analysed from PCR- and IFAT-negative horses 1 was PCR posit...
Comparative evaluation of the sensitivity of LAMP, PCR and in vitro culture methods for the diagnosis of equine piroplasmosis. The sensitivity of LAMP, PCR and in vitro culture methods for the detection of Theileria equi and Babesia caballi was evaluated using tenfold serially diluted culture parasites. On day 1 post-culture, both T. equi and B. caballi parasites could only be observed at 1% parasite dilution from the in vitro culture method, whereas LAMP could detect up to 1 x 10(-3)% of both T. equi and B. caballi parasite dilutions, whilst PCR could detect 1 x 10(-3)% T. equi and 1 x 10(-1)% B. caballi parasite dilutions. On day 7 post-culture, the detection limit for T. equi and B. caballi in the in vitro culture ...
A serological study of Babesia caballi and Theileria equi in Thoroughbreds in Trinidad. Ninety-three (93) horses were investigated for serum antibodies to Theileria equi (T. equi) and Babesia caballi (B. caballi) using the immunofluorescent antibody test (IFAT). Seventy-seven (82.8%) horses were seropositive; 31 (33.3%) were positive to T. equi compared to 64 (68.8%) to B. caballi while 18 (19.4%) horses were seropositive to both parasites. No significant differences in antibody frequencies among females and males for either T. equi or B. caballi were noted. Differences in seropositivity to B. caballi among age groups were not significant. Antibodies to T. equi were more frequent...
Equine piroplasmoses at the reintroduction site of the Przewalski’s horse (Equus ferus przewalskii) in Mongolia. Piroplasmosis has been identified as a possible cause of mortality in reintroduced Przewalski's horses (Equus ferus przewalskii) in the Dsungarian Gobi (Mongolia). A cross-sectional and a longitudinal study were conducted in a representative sample (n = 141) of the resident domestic horse population and in 23 Przewalski's horses to assess the prevalence of Theileria equi and Babesia caballi. Piroplasms were detected in blood by light microscopy in 6.7% (95% confidence interval [CI]: 3.6-12.2%) of the domestic horse samples. Antibody prevalence was 88.6% (95% CI: 82.4-92.9%) for T. equi and 75....
Development of loop-mediated isothermal amplification (LAMP) method for diagnosis of equine piroplasmosis. Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid method whereby DNA is amplified with high specificity, efficiency, and rapidity under isothermal conditions using a set of four specifically designed primers and a DNA polymerase with strand displacement activity. In this study, we used LAMP primer sets designed from EMA-1 and Bc 48 genes for detection of Theileria equi and Babesia caballi infections, respectively. These primer sets specifically amplified DNA of the respective parasites. Both primer sets amplified T. equi and B. caballi up to 10(-6) dilution of 10-fold seria...
Seroepidemiological evidence for the possible presence of Babesia (Theileria) equi and Babesia caballi infections in donkeys in western Xinjiang, China. The prevalence of Babesia (Theileria) equi and B. caballi infections in donkeys in western Xinjiang China was investigated. In total, 93 serum samples were randomly taken from donkeys in the Kashi and Ili areas, and examined for B. equi and B. caballi infections by enzyme-linked immunosorbent assays using recombinant antigens. Of the 93 samples, 9 (9.6%) and 36 (38.7%) samples were positive for B. equi infection and B. caballi infection, respectively. In addition, 2 (2.2%) samples were positive for both B. equi and B. caballi infections. These results indicate that equine babesiosis might be e...
Use of an in vitro culture system to detect Theileria equi strains from infected equids and/or reservoirs. A horse erythrocyte culture technique, partly modifying that originally developed by Holman, was used to detect the presence of Theileria equi strains in 12 horse and 2 mule blood samples. The animals were placed into four groups on the basis of their case history and laboratory test results: the mules and two horses were considered as infected and included in the 'recent infection' group, four horses with a history of past infection were included in the 'past infection' group and four animals subjected to anti-theileria treatment formed the 'treated animals' group. The final group consisted o...
Immunochromatographic test for simultaneous serodiagnosis of Babesia caballi and B. equi infections in horses. An immunochromatographic test for the simultaneous detection of Babesia caballi- and B. equi-specific antibodies (BceICT) was developed using a recombinant B. caballi 48-kDa rhoptry protein (rBc48) and a recombinant truncated B. equi merozoite antigen 2 (rEMA-2t). An evaluation of the ability of the BceICT to detect antibodies in sera from uninfected horses and experimentally infected horses showed high sensitivities and specificities of 83.3% (10/12 sera) and 92.9% (52/56 sera), respectively, for the anti-B. caballi antibody and 94.1% (16/17 sera) and 88.2% (45/51 sera), respectively, for the...
[An epidemiological survey of equine anaplasmosis (Anaplasma phagocytophilum) in southern France]. Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum and transmitted by Ixodes spp. ticks. According to some reports the disease can be introduced into disease-free zones by migrating birds. The purpose of this study was to evaluate the seroprevalence of A. phagocytophilum in horses in the Camargue. Data concerning 424 horses were gathered and the sera were tested for A. phagocytophilum and for piroplasmoses using an enzyme-linked immunosorbent assay and a complement fixation test, respectively. The seroprevalence rates were 11.3 % for A. phagocytophilum, 64.4 % for Theileria equi...
Evaluation of enzyme-linked immunosorbent assays with recombinant antigens for the serodiagnosis of equine Babesia infections. Two enzyme-linked immunosorbent assays (ELISA) with recombinant protein as antigens were evaluated by comparison with the indirect fluorescent antibody tests (IFAT) for the detection of specific antibodies to Babesia caballi and Babesia equi, respectively in 380 sera from experimentally infected, uninfected, and field horses. The high concordances of 92.4% (351/380) and 98.2% (373/380) between ELISA and IFAT for B. caballi and B. equi, respectively suggest that ELISA, especially for B. equi infection, could be alternative to the corresponding IFAT for serodiagnoses of equine piroplasmosis, alt...
Babesia–a historical overview. The history of the genus Babesia is briefly outlined. The classical differences with the main other genus of non-pigment-forming hemoparasites, Theileria, are the absence of extra-erythrocytic multiplication (schizogony) in Babesia and the cycle in the vector tick, which includes transovarial transmission in Babesia but only transstadial transmission in Theileria. Also, the multiplication in the red cell of Babesia, by budding, most often results in two daughter cells (merozoites), while that of Theileria gives four merozoites, often as a Maltese cross. In particular this means that what is st...
Development of specific immunoglobulin Ga (IgGa) and IgGb antibodies correlates with control of parasitemia in Babesia equi Infection. In this study, the kinetics of specific immunoglobulin G (IgG) isotypes were characterized in Babesia equi (Theileria equi)-infected horses. IgGa and IgGb developed during acute infection, whereas IgG(T) was detected only after resolution of acute parasitemia. The same IgG isotype profile induced during acute infection was obtained by equi merozoite antigen 1/saponin immunization.
[A literature review of equine piroplasmosis after an episode of acute babesiosis in a Dutch Standardbred foal after a stay in Normandy]. Piroplasmosis, a disease endemic to most tropical and subtropical areas, appears to be spreading to more temperate zones. This article gives a review of equine piroplasmosis and describes an acute case of infection with Babesia caballi in a Dutch Standard bred foal after a short stay at a stud in Normandy (France). A 3-month-old stallion foal was presented with lethargy, fever of 41 degrees C, and pale mucosal membranes. Haematology revealed a low packed cell volume (14 l/l) leucytosis (25 G/l) and a high blood urea nitrogen concentration (20.1mmol/l). Infection with B. caballi was diagnosed o...
Ability of the vector tick Boophilus microplus to acquire and transmit Babesia equi following feeding on chronically infected horses with low-level parasitemia. The protozoan parasite Babesia equi replicates within erythrocytes. During the acute phase of infection, B. equi can reach high levels of parasitemia, resulting in a hemolytic crisis. Horses that recover from the acute phase of the disease remain chronically infected. Subsequent transmission is dependent upon the ability of vector ticks to acquire B. equi and, following development and replication, establishment of B. equi in the salivary glands. Although restriction of the movement of chronically infected horses with B. equi is based on the presumption that ticks can acquire and transmit the ...
Theileria (Babesia) equi and Babesia caballi infections in horses in Galicia, Spain. The control of equine piroplasmosis is becoming increasingly important to maintain the international market open to the horse industry. The purpose of this study was to demonstrate the occurrence of equine piroplasmosis (Theileria equi and Babesia caballi) in Galicia, north-west Spain, and to compare haematological and serum biochemistry parameters between non-parasitaemic horses and horses parasitaemic with T. equi and B. caballi. Sixty serum samples (control group) were taken from healthy horses pastured on two farms, and examined for evidence of equine T. equi and B. caballi infection by in...
Development of a single-round and multiplex PCR method for the simultaneous detection of Babesia caballi and Babesia equi in horse blood. With the aim of developing more simple diagnostic alternatives, a differential single-round and multiplex polymerase chain reaction (PCR) method was designed for the simultaneous detection of Babesia caballi and Babesia equi, by targeting 18S ribosomal RNA genes. The multiplex PCR amplified DNA fragments of 540 and 392 bp from B. caballi and B. equi, respectively, in one reaction. The PCR method evaluated on 39 blood samples collected from domestic horses in Mongolia yielded similar results to those obtained from confirmative PCR methods that had been established earlier. Thus, the single-roun...
