首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Equine piroplasmosis due to Theileria equi and Babesia caballi is endemic in Trinidad. A case of equine piroplasmosis due to T. equi was diagnosed in a thoroughbred foal at 10h post-partum. A high parasitaemia (63%) of piroplasms was observed in a Wright-Giemsa(?) stained thin blood smear from the foal. In addition, the 18S rRNA gene for Babesia/Theileria was amplified from DNA extracted from the blood of the foal and the mare. Amplified products were subjected to a reverse line blot hybridization assay (RLB), which confirmed the presence of T. equi DNA in the foal. The mare was negative by RLB but was positive for T. equi using a nested PCR and sequence analysis. In areas where equine piroplasmosis is endemic, severe jaundice in a post-partum foal may be easily misdiagnosed as neonatal isoerythrolysis. Foals with post-partum jaundice should be screened for equine piroplasmosis, which may be confirmed using molecular methods if available.  相似文献   

2.
Specific oligonucleotide probes were designed to develop a new and highly sensitive reverse line blot assay to detect and identify simultaneously different Theileria and Babesia species in horses. The amplified hypervariable V4 region of the 18S rRNA gene was hybridised against different generic and species-specific probes. The survey was conducted over 243 samples of equine blood divided into three different groups: group 1, 24 horses presented as possible clinical piroplasmosis; group 2, 181 clinically healthy free-ranging horses exposed to ticks; group 3, 38 riding horses with unrelated pathologies and low or no contact with ticks. The study demonstrated a high piroplasm prevalence in the first two groups of animals. Two Theileria genotypes sharing 96.8% similarity between their 18S rRNA gene sequences and two Babesia genotypes sharing 97.4% similarity, were identified. The biologic meaning of such genotypes is discussed in terms of their phylogenetic relationships and potential pathogenicity.  相似文献   

3.
Corridor disease, caused by the tick-borne protozoan parasite Theileria parva, is a controlled disease in South Africa. The Cape buffalo is the reservoir host and uninfected buffalo have become sought-after by the game industry in South Africa, particularly for introduction into Corridor disease-free areas. A real-time polymerase chain reaction (PCR) test for detection of T. parva DNA in buffalo and cattle was developed to improve the sensitivity and specificity of the official diagnostic test package in South Africa. Oligonucleotide primers and hybridization probes were designed based on the 18S ribosomal RNA (rRNA) gene. Amplification of control DNA using Theileria genus-specific primers resulted in detection of T. taurotragi and T. annulata, in addition to T. parva. A T. parva-specific forward primer was designed which eliminated amplification of all other Theileria species, except for Theileria sp. (buffalo); however only the T. parva product was detected by the T. parva-specific hybridization probe set. The real-time PCR assay requires less time to perform, is more sensitive than the other molecular assays previously used in T. parva diagnostics and can reliably detect the parasite in carrier animals with a piroplasm parasitaemia as low as 8.79 x 10(-4)%.  相似文献   

4.
Canine infection by vector-borne hemoparasites is frequent in tropical and sub-tropical areas where exposure to hematophageous ectoparasites is intensive. A reverse line blot (RLB) assay was designed to improve the simultaneous detection of all named canine piroplasm species combined with other vector-borne pathogens of dogs including Ehrlichia canis, Hepatozoon canis and Leishmania infantum common in the Mediterranean basin. Blood samples of 110 dogs from Spain (n = 21), Portugal (n = 14) and Israel (n = 75) were analyzed. The study evaluated 2 groups of dogs, 49 dogs with piroplasm infection detected by blood smear microscopy from Portugal, Spain and Israel, and 61 dogs surveyed from rural areas in Israel, for which infection status with vector-borne pathogens was unknown. Among the dogs previously diagnosed with piroplasmosis, infection with Babesia canis, Babesia vogeli, Babesia gibsoni and Theileria annae was detected in the Iberian dogs while only B. vogeli was found in Israeli dogs. These differences are attributed to the absence of tick vectors for some piroplasm species such as Dermacentor reticulatus in Israel. Eleven (79%) of the Babesia-positive dogs from Portugal were co-infected with other pathogens including L. infantum, H. canis and E. canis. Eight of 61 (13%) rural Israeli dogs were co-infected with two or more pathogens including B. vogeli, L. infantum, E. canis, and H. canis. Triple infections were demonstrated in 2 dogs. The RLB detection limit for Babesia was 50-fold lower than that of PCR. This study presents a RLB to simultaneously detect and separate the major vector-borne dog pathogens in southern Europe and the Middle East.  相似文献   

5.
During 1996 a small, ring-shaped, piroplasm was observed in blood smears from 157 dogs in north-west Spain. None of them had previously been in areas endemic for Babesia gibsoni, which was until recently the only small piroplasm known to parasitise dogs. Haematological and serum biochemistry analyses showed that almost all the dogs had an intense regenerative haemolytic anaemia and that in some cases there was evidence of renal failure. A molecular study was made of a sample of the parasite obtained in June 2000. The phylogenetic analysis showed an identity of 100 per cent with the new piroplasm, provisionally denominated as Theileria annae, and 99 per cent with Babesia microti and B. microti-Japan. The results confirm the previous observation of a new form of piroplasm (Theileria annae) which causes disease in dogs in Europe and suggest that it is endemic among the canine population in north-west Spain.  相似文献   

6.
Equine piroplasmosis caused by Babesia caballi and Theileria equi is widespread in Asia. The presence of these haemozoans in Mongolia was previously confirmed in domestic as well as in reintroduced Przewalski horses in which they cause significant pathology. The data on occurrence of piroplasms from Bactrian camels in Asia is lacking. A total of 192 horses, 70 Bactrian camels, and additional 16 shepherd dogs from the Hentiy province were included in our study. No clinical signs typical for piroplasmid infection were observed during the field survey. Microscopic examination revealed the presence of T. equi in blood smears from 67% of examined horses, with camels and dogs being negative. A two step PCR approach was used to detect piroplasms in peripheral blood. In the first "catch all" PCR reaction, amplification of the 496 bp-long fragment of the SSU rRNA gene enabled the detection of Babesia and Theileria spp. Second round multiplex PCR reaction used for species discrimination allowed the amplification of T. equi- and B. caballi-specific 340 bp and 650 bp-long regions of the SSU rRNA, respectively. This assay detected T. equi in 92.7% of horses, while the infections with B. caballi and dual infections were rare. In both PCR setups, camels and dogs were negative indicating that in the studied region, these hosts do not share piroplasms with horses.  相似文献   

7.
Seven healthy sheep and 10 sheep diagnosed with piroplasmosis based on clinical signs were tested for the presence of babesiae and theileriae. Using the molecular techniques, two species of theileriae were detected and characterized. Theileria ovis was present mostly in healthy sheep and in Rhipicephalus ticks collected from infected sheep. Theileria sp. OT3 parasite was detected mostly in ill animals which represent additional evidence to the possible pathogenic nature of Theileria sp. OT3. The presence of babesiae in sheep or in ticks was not determined. The results of this study showed that ovine piroplasmosis due to Theileria is present in Southern Croatia. It was concluded that clinical diagnosis of ovine piroplasmosis should be confirmed by molecular analysis in order to identify the species of piroplasm, to select the appropriate treatment and to exclude the threat for public health.  相似文献   

8.
A TaqMan-based real-time PCR assay was developed for the diagnosis of Anaplasma marginale infection of cattle. The established assay was proven to be highly specific, since no cross-reactions were observed with other Anaplasma species of ruminants, including the closely related Anaplasma centrale, or other haemoparasites of ruminants (Anaplasma bovis, Anaplasma ovis, Anaplasma phagocytophilum, Babesia bovis, Babesia bigemina, Theileria annulata and Theileria buffeli). The detection limit was equal to that of nested (n)PCR (10(1) copies of standard DNA and 3 x 10(1) infected erythrocytes ml(-1) of blood). The assay was also reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. Fifty-four blood samples of ruminants (cattle, n = 51; sheep, n = 2; goats, n = 1), that had been tested previously by reverse line blot (RLB) hybridisation, were subjected to an nPCR assay and the newly established real-time PCR assay. By using real-time PCR, A. marginale DNA was detected in 39/51 bovine samples, with DNA titres ranging from 3.60 x 10(3) to 5.70 x 10(8) copies ml(-1) of blood, whereas sheep and goat samples tested negative. The concordance with nPCR was 100%, whereas a unique sample that had tested negative by RLB gave positive results by nPCR and real-time PCR. The established assay could overcome the limitations of existing diagnostic methods, allowing for simultaneous detection and quantification of the A. marginale DNA in bovine blood, that is essential to support the clinical diagnosis, to assess the carrier status of the animals and to evaluate the efficacy of vaccines and antirickettsial drugs.  相似文献   

9.
Detection and identification of Theileria and Babesia species in 920 apparently healthy small ruminants in eastern Turkey, as well as parasite genetic diversity, was investigated using a specifically designed reverse line blot (RLB) assay. The hypervariable V4 region of the 18S ribosomal RNA (rRNA) gene was amplified and hybridized to a membrane onto which catchall and species-specific oligonucleotide probes were covalently linked. Three Theileria and one Babesia genotype were identified. Comparison of the Theileria genotypes revealed 93.6-96.2% similarity among their 18S rRNA genes. Two Theileria shared 100% and 99.7% similarity with the previously described sequences of T. ovis and Theileria sp. OT3, respectively. A third Theileria genotype was found to be clearly different from previously described Theileria species. The genotype was provisionally designated as Theileria sp. MK. The Babesia genotype shared 100% similarity with Babesia ovis. The survey indicated a high prevalence of piroplasm infections in small ruminants (38.36%). Theileria spp. prevalence was 36.08%. Prevalence of B. ovis was 5.43%. The most abundant Theileria species identified was T. ovis (34.56%) followed by Theileia sp. MK (1.30%) and Theileria sp. OT3 (0.43%).  相似文献   

10.
Babesia canis has generally been considered the only large Babesia to infect dogs. Here we describe the molecular characterization of a large Babesia species that was detected in the blood and bone marrow of a dog with clinical and hematological abnormalities consistent with babesiosis. Analysis of the 18S rRNA genes revealed a unique sequence that shared 93.9% sequence identity with B. bigemina and 93.5% sequence identity with B. caballi, compared to 91.2-91.6% identity with B. canis canis, B. c. vogeli, and B. c. rossi. Cross-reactive antibodies against B. canis, B. gibsoni (Asian genotype), or B. gibsoni (California genotype) antigens were not detected in acute or convalescent serum samples. The dog was treated with imidocarb diproprionate, which resulted in the resolution of clinical signs, and subsequently Babesia DNA was not detectable by PCR in post-treatment samples. The organism described in this report represents a genetically unique large Babesia sp. and is the eighth genetically distinct piroplasm capable of infecting the domestic dog.  相似文献   

11.
Intraerythrocytic protozoan species of the genera Theileria and Babesia are known to infect both wild and domestic animals, and both are transmitted by hard-ticks of the family Ixodidae. The prevalences of hemoprotozoa and ectoparasites in 15 free-living Mazama gouazoubira, two captive M. gouazoubira and four captive Blastocerus dichotomus from the State of Minas Gerais, Brazil, have been determined through the examination of blood smears and the use of nested polymerase chain reaction (nPCR). The cervid population was inspected for the presence of ticks and any specimens encountered were identified alive under the stereomicroscope. Blood samples were collected from all 21 animals, following which blood smears were prepared, subjected to quick Romanowsky staining and examined under the optical microscope. DNA was extracted with the aid of commercial kits from cervid blood samples and from tick salivary glands. The nPCR assay comprised two amplification reactions: the first was conducted using primers specific for a 1700 bp segment of the 18S rRNA gene of Babesia and Theileria species, whilst the second employed primers designed to amplify a common 420 bp Babesia 18S rRNA fragment identified by aligning sequences from Babesia spp. available at GenBank. The ticks Amblyomma cajennense, Rhipicephalus microplus and Dermacentor nitens were identified in various of the cervids examined. Of the animals investigated, 71.4% (15/21) were infected with hemoprotozoa, including Theileria cervi (47.6%), Theileria sp. (14.3%), Babesia bovis (4.8%) and Babesia bigemina (4.8%). However, only one of the infected wild cervids exhibited accentuated anaemia (PCV=17%). This is first report concerning the occurrence of Theileria spp. in Brazilian cervids.  相似文献   

12.
DNA of two species of piroplasmids was detected in dromedaries during a survey of blood protozoans in Jordan between 2007 and 2009. Ten clinically healthy camels (10%) originating from three Jordanian districts were found, using a PCR assay, to harbor Theileria or Babesia species in their blood and no mix infection was determined. Analysis of the partial 18S rRNA gene sequences of these parasites allowed their unambiguous identification as equine piroplasmids Babesia caballi (n=6) and Theileria equi (n=4). In case of latter species, a novel genotype was found in horses. This first molecular-based species determination of piroplasmids from camels further contributes to the growing evidence of low host specificity of piroplasmids.  相似文献   

13.
Small piroplasms as a cause of canine babesiosis in southern California were first documented in 1990. Initially these piroplasms were considered to be Babesia gibsoni, the only small Babesia parasite known to infect dogs at that time. In the following decade, the use of molecular analysis made it clear that small canine Babesia in fact are comprised of at least three distinct species, and the isolates from dogs in southern California were not B. gibsoni. Molecular, antigenic, and morphological characteristics of the southern California species of canine piroplasm supported naming it as a distinct species, Babesia conradae. The renaming of this species prompted this literature review of small canine piroplasms in California in order to clarify clinical, diagnostic, epidemiological, and molecular characteristics of B. conradae in comparison to other small canine piroplasms. Clinical symptoms of B. conradae are similar to those of B. gibsoni; however, B. conradae infections may be more pathogenic, resulting in higher parasitaemia and more pronounced anaemia when compared with B. gibsoni-infected dogs. The immunofluorescent antibody test is the most commonly used test to diagnose B. conradae. It is important to specify which small Babesia species to test for since there is little serological cross reactivity between the small canine Babesia antigens or cross-detection in the newer molecular tests. Molecular characterization of B. conradae, based principally on the 18S small subunit rRNA gene, and recently the second internal transcribed spacer region, demonstrate that B. conradae is most closely related to piroplasms recovered from humans and animals in the western United States.  相似文献   

14.
为了鉴定从汉中市牛体表采集到的蜱种类及其携带病原梨形虫(Piroplasma)的种类,在形态学初步观察的基础上,用PCR技术基于线粒体16SrDNA对蜱种类进行了分子鉴定,并基于梨形虫18S rRNA基因分别检测蜱体内携带巴贝斯虫属(Babesia)、泰勒虫属(Theileria)等病原情况.结果显示,所采集到的67只...  相似文献   

15.
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 still commonly called Babesia microti is not a Babesia and that it would be just as logical to speak of human theileriosis as of babesiosis. The small piroplasm of horses, long known as Babesia equi, is already commonly designated as Theileria equi. However, on molecular grounds, it may be necessary to create a new genus for these parasites. The Babesia species of domestic animals are briefly discussed and presented in a table.  相似文献   

16.
Babesiosis and Theileriosis are tick-borne diseases widespread in tropical and sub-tropical regions with high economic impact worldwide. In Portugal there are at least 4 tick vectors known to be competent for the transmission of Babesia and Theileria sp. identified: Rhipicephalus bursa, Rhipicephalus (Boophilus) annulatus, Ixodes ricinus and Haemaphysalis punctata. All these potential Babesia and Theileria tick vectors are widely distributed in Portugal, although they are predominant in the Southern region. In this study, 1104 cattle blood samples were randomly collected from Central and Southern regions of Portugal and analyzed by PCR-reverse line blotting (RLB) for the detection of Babesia and Theileria sp. Testing indicated that 74.7% of the bovines tested were positive for either Babesia and/or Theileria sp. In addition, five different apicomplexan species, namely, Theileria buffeli, Theileria annulata, Babesia divergens, Babesia bovis, and Babesia bigemina were detected by RLB among the bovines tested. T. buffeli was the most frequently found species, being present in 69.9% of the positive samples either as single infections (52.4%), or as mixed infections (17.5%). The Babesia specie most frequently found was B. divergens, detected in 4.2% of the infected bovines. Overall, infected bovines were found in all regions tested; however the highest number of infected bovines was observed in évora district (96.2%) and in cattle from Limousin breeds (81.7%). The results indicate widespread Babesia and Theileria infections in Portuguese bovines, suggesting the need for improved control of ticks and tick-borne diseases.  相似文献   

17.
Equine piroplasmosis (EP) has not been considered indigenous in The Netherlands. However, following the detection of an apparently indigenous subclinical Babesia caballi infection in a horse on Schouwen-Duiveland (an island in the Zeeland Province), a survey was undertaken between May and September 2010 to assess the prevalence of the causative agents of EP in the South-West of The Netherlands. Blood samples from 300 randomly selected horses were tested for specific antibodies against Theileria equi and B. caballi using an indirect fluorescence antibody test (IFAT), and for parasite DNA using a specific polymerase chain reaction combined with reverse line blotting (PCR-RLB). Twelve of the horses (4%) were seropositive for EP. Of these, nine (75%) were positive (titre?1:160) for B. caballi alone and three (25%) were also positive for T. equi. PCR-RLB detected T. equi DNA in five horses (1.6%), two of which were seronegative. Four (1.3%) of the positive horses (three positive for T. equi and one for both B. caballi and T. equi) were considered truly indigenous. During the study, two indigenous ponies from a farm situated outside the sampling area were diagnosed with acute clinical piroplasmosis characterized by severe anaemia and pyrexia. Blood smears showed T. equi - like inclusions in red blood cells, and T. equi infection was confirmed in both ponies by PCR-RLB. The initial subclinical B. caballi infection, the survey results and the two acute clinical EP cases confirmed the autochthonous transmission of B. caballi and T. equi infections in The Netherlands.  相似文献   

18.
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 serially diluted samples. Furthermore, DNA extracted from blood collected from a horse experimentally infected with T. equi was amplified by a T. equi LAMP primer set from days 2 to 35 post-infection, demonstrating the high sensitivity of these primers. Of 55 samples collected from China, 81.8% and 56.3% were positively detected by LAMP for T. equi and B. caballi infections, respectively. In contrast, 91.8% and 45.9% of the 37 samples collected from South Africa were LAMP positive for T. equi and B. caballi, respectively. These results suggest that LAMP could be a potential diagnostic tool for epidemiological studies of equine piroplasmosis.  相似文献   

19.
New insights into the epidemiology of bovine piroplasmoses in Italy   总被引:1,自引:0,他引:1  
Few studies have been published on bovine piroplasmoses in Italy, and therefore a clear picture of the epidemiology of these infections is difficult to obtain. Vertebrate and invertebrate hosts in Central and Northern Regions of Italy were investigated in 2005 and 2006, when microscopy, molecular tools and serological tests were applied to 468 blood samples drawn from cattle in order to evaluate the presence of these protozoa and identify possible risk factors. Ticks were also collected, identified and analyzed by molecular techniques.Microscopy identified 6.5% of the animals as positive, whereas PCR detected piroplasm DNA in 21.6%. BLAST analysis showed 67 amplicons (17.0%) referable to the Theileria sergenti/buffeli/orientalis group, 17 (4.3%) to Theileria annae, and 1 to Babesia divergens. Serology evidenced a prevalence of 45.4% for Babesia bovis, 17.4% for Babesia bigemina, and 34.9% for B. divergens. The 127 collected ticks were identified as belonging to 5 species, mostly represented by Rhipicephalus bursa, Hyalomma marginatum and Ixodes ricinus. Molecular analyses evidenced the presence of B. bovis and B. bigemina, in 3 and 5 ticks, respectively.Our findings suggest that different species of piroplasms are circulating in bovine populations in Central and Northern Italy, and provide new insights into the complex epidemiology of bovine piroplasmoses in Italy.  相似文献   

20.
Buparvaquone, a naphthoquinone with known efficacy against Theileria parva parva in cattle, was tested for activity against Theileria cervi piroplasms in both an in vitro culture system and in vivo in experimentally infected white-tailed deer. The in vitro data showed a significant decrease in the incorporation of 3H-hypoxanthine by infected red blood cells treated with buparvaquone when compared to that seen with imidocarb and chloroquine treatment. In both intact and splenectomized deer treated with buparvaquone (2.5 mg kg-1) a gradual decrease in piroplasm parasitaemia was observed following treatment. However, in the splenectomized deer, parasitaemia levels returned to near pretreatment values after approximately 2 weeks.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号