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1.
Babesia divergens was cultivated in sheep erythrocytes in RPMI 1640 supplemented with 10% Fetal Calf Serum (FCS) or sheep serum. In vitro cultures in sheep red blood cells were initiated with human erythrocytes infected in vitro with B. divergens Rouen 1987 or with gerbil blood infected with several isolates from bovine origin. After the first subcultures on sheep erythrocytes, a ten-fold multiplication of the parasites was obtained within 48 h. Erythrocytes from three splenectomized sheep were infected in vitro with B. divergens; when parasitaemia reached 10%, the animals were inoculated with homologous parasitized erythrocytes. All sheep expressed hyperthermia with a peak between the 6th and the 9th day post-infection (p-i) and a transitory parasitaemia 10 days p-i. In vitro primary cultures were performed on two of these sheep, demonstrating the parasite persistence at very low parasitaemia in the infected animals. Splenectomized sheep can be used as a new model for B. divergens chronic infection. 相似文献
2.
Previously unpublished data from 1958 to 1967 attest the occurrence of Babesia divergens in cattle in several endemic foci of Northeast Hungary. During that period the number of clinical cases showed fluctuation with intervals of 4-5 years and monophasic seasonality (peaking in June). In order to assess the current status of bovine babesiosis in that region, blood samples were collected from 654 cattle on 44 farms of 36 settlements in or near the endemic area during 2005, and serum levels of IgG antibodies to B. divergens were measured by indirect fluorescent antibody test (IFAT). Only 2 samples (0.3%) showed positivity. In one village clinical babesiosis was observed over the past few years. Animals brought into the endemic area during the spring developed haemoglobinuria in the summer of the same year, but those introduced during the summer or autumn showed clinical signs only after two years. Sampled animals born and raised locally had neither haemoglobinuria nor seroconversion. Reduction in the number of cases during the past decades may have been influenced by the availability of hosts (i.e. decrease of cattle breeding) and the activity of vectors associated with climate-related changes (e.g. increase of annual sunlight hours in the endemic area). This is the first report on the prevalence of antibodies to B. divergens in cattle in Hungary. 相似文献
3.
To assess the epidemiology of Babesia divergens in a veterinary practice based in the mid-east of France ("Monts du Lyonnais"), blood was collected from 254 cattle belonging to 24 herds. To assess the dynamics of the carrier state, six carriers were identified, treated with flumethrin and sampled once every 3 weeks during 6 months. Two different DNA extraction methods were compared. Each sample was tested for the presence of parasites using a PCR-RFLP test based on the 18S rRNA gene. The sensitivity of the test was equivalent to a parasitaemia as low as 10(-5)% (in "Filter Paper" samples) and 10(-6)% in 1 ml blood (extracted using "Matrix"). With the latter method, the rate of detection diminishes in the low parasitaemia range but could probably be improved. This test proved to be very useful in the detection of B. divergens carriers. Serology using IFAT showed 7% of the cattle seropositive, which is suggestive of a disease situation with a low clinical risk level. Analysis of the PCR results suggests a 20% prevalence rate of carriers in the cattle population. The use of the mean parasitaemia is proposed to serve as a babesiosis clinical risk indicator. This approach could also be used in other babesia infections provided the lowest detectable parasitaemia level (threshold level) could be resolved for each parasite species. 相似文献
4.
The effects of continuous oxytetracycline administration on the development of parasitaemia of Babesia divergens during both natural and artificial infections were studied. During natural exposure on grazing heavily infested with Ixodes ricinus, seven out of 42 cattle with no previous exposure to tick-borne diseases were injected every four days with a long acting preparation of oxytetracycline at a dose rate of 20 mg/kg. During the six week grazing period 21 untreated cattle developed a patent parasitaemia of B divergens and all became seropositive by the fluorescent antibody test. In contrast, no parasites were observed in treated cattle and antibody titres remained low. Artificial infections were studied with different dose levels of oxytetracycline and their effects on antibody stimulation noted. First, four groups of cows were infected with 10(8) erythrocytes infected with B divergens, three groups being injected every four days with the long acting oxytetracycline formulation at dose levels of 20, 10 and 5 mg/kg, respectively. The highest level completely inhibited parasite replication and antibody formation; the same was observed in one animal dosed at 10 mg/kg but the remainder, plus those treated at 5 mg/kg, developed both low parasitaemia and high antibody titres. The untreated cows developed severe babesiosis. A further untreated control group was added and three weeks after cessation of oxytetracycline treatment all were infected with 10(9) erythrocytes infected with a homologous isolate of B divergens. The controls, plus those in which the previous infection had been completely inhibited, developed severe clinical babesiosis but the remainder were refractory to parasite development. 相似文献
5.
A survey of Theileria parasites in cattle in eastern Turkey was carried out using specific polymerase chain reaction. A total of 252 blood samples were collected from clinically healthy cattle between June and July 2004. Of 252 blood samples examined, 41 (16%) were positive for piroplasms by microscopy, whereas 114 (45%) were positive for the presence of at least one species of Theileria by PCR. The percentages of positive animals for Theileria annulata and benign Theileria species (Theileria sergenti/buffeli/orientalis) were 39% (99/252) and 7% (18/252), respectively. By allele-specific PCR examination of 18 field isolates which were positive for benign Theileria parasites, 8 samples were only amplified by B-type specific primers and 10 samples were amplified by both of the B and C-type specific primers, indicating a mixed infection with B and C-type of the parasite. None of the field isolates was amplified by I-type specific primers. Three samples were co-infected with T. annulata and benign Theileria parasites. Two of them which were infected with B-type parasite were also infected with T. annulata, the other sample which was infected both of B and C-type parasites was also infected with T. annulata. A total of 724 ixodid ticks were collected from the cattle. Hyalomma anatolicum anatolicum was the dominant species with 32% (230/724) in the region. H. a. excavatum, Boophylus annulatus and Rhipicephalus bursa represented 25% (183/724), 19% (140/724) and 15% (112/724) of the total number of ticks, respectively. R. sanguineus was the minor species and represented 8% (59/724) of the tick population. 相似文献
6.
ABSTRACT: Babesia divergens is a tick-transmitted apicomplexan parasite for which asexual multiplication in its vertebrate hosts is restricted to erythrocytes. Current knowledge of invasion of these target cells is limited. An efficient in vitro invasion assay was set up to gain access to this information. Parasites prepared from infected RBC, lysed by electroporation, and mixed with bovine RBC in a selected synthetic medium (RPMI 1640 supplemented with calcium) were able to establish subsequent cultures with parasitemia ranging from 6 to 14%. Free parasites remaining in the invasion medium could be eliminated by Percoll gradient and culture could be pursued with the freshly invaded erythrocytes. In this way, the invasion time window could be shortened to obtain a synchronised start of the culture or to study the kinetics of invasion. With this assay we demonstrate that 1) erythrocyte invasion by B. divergens is a rapid process since 70% of the invasion-competent parasites invaded the RBC in less than 45 s; 2) all invasion-competent parasites achieved invasion within 10 min of contact; 3) one erythrocyte could be invaded concomitantly by two merozoites; 4) despite a synchronous start, the parasite population evolved heterogeneously resulting in a progressive loss of synchronisation. Western blot analysis of proteins collected from invasion medium were performed with sera from animals experimentally infected with B. divergens and highlighted several proteins. The dose-dependent, inhibitory effects of these sera on B. divergens invasion suggest that these proteins might be involved in the invasion process. Further investigations are required for their characterisation. 相似文献
7.
OBJECTIVE: To assess the effect of breed of cattle on the transmission rates of and innate resistance to Babesia bovis and B bigemina parasites transmitted by Boophilus microplus ticks. DESIGN: Groups of 56 purebred B indicus and 52 B indicus cross B taurus (50%, F1 generation) steers were placed in a paddock seeded with and also naturally infested with B microplus which were the progeny of females ticks fed on B taurus cattle specifically infected with a virulent isolate of B bovis. The cattle were placed in the infested paddock 50 days after seeding had started. PROCEDURE: Cattle were inspected from horseback daily for 50 days. Clinically ill cattle were brought to yards and assessed by monitoring fever, depression of packed-cell volume, parasitaemia and severity of clinical signs. Any animals that met preset criteria were treated for babesiosis. Blood samples were collected from all cattle on day 28, 35 and 42 after exposure and antibodies to Babesia spp and packed cell volume measured. RESULTS: All steers, except for one crossbred, seroconverted to B bovis and B bigemina by day 35 and 75% of the crossbred steers showed a maximum depression in packed cell volume of more than 15% due to infection with Babesia spp compared with only 36% of the B indicus group. Ten of the 52 crossbreds and 1 of the 56 B indicus steers showed severe clinical signs. Two of the crossbreds required treatment of which one died 2 weeks after initial treatment. CONCLUSIONS: Pure-bred B indicus cattle have a high degree of resistance to babesiosis, but crossbred cattle are sufficiently susceptible to warrant the use of preventive measures such as vaccination. Transmission rates of B bovis and B bigemina to B indicus and crossbred cattle previously unexposed to B microplus were the same. 相似文献
8.
Tick-borne diseases are of increasing concern in many countries, particularly as a consequence of changes in land use and climate. Ticks are vectors of numerous pathogens (viruses, bacteria, protozoa) that can be harmful to humans and animals. In the context of animal health, bovine babesiosis poses a recurrent threat to cattle herds. In this study, we use a modeling approach to investigate the spread of babesiosis and evaluate control measures. A previously developed tick population dynamics model (here, Ixodes ricinus) is coupled with a pathogen spread model (here, the protozoan Babesia divergens), which describes pathogen spread in a dairy herd through the following processes: transmission, acquisition, transovarial transmission, transstadial persistence, and clearance of the pathogen. An assessment of the simulated B. divergens prevalence levels in ticks and cattle in the context of existing knowledge and data suggested that the model provides a realistic representation of pathogen spread. The model was then used to evaluate the influence of host density and the effect of acaricides on B. divergens prevalence in cattle. Increasing deer density results in an increase in prevalence in cattle whereas increasing cattle stocking rate results in a slight decrease. A potential increase in deer density would thus have an amplification effect on disease spread due to the increase in the number of infected ticks. Regular use of acaricides produces a reduction in pathogen prevalence in cattle. This model could be adapted to other tick-borne diseases. 相似文献
9.
Góes TS Góes VS Ribeiro MF Gontijo CM 《Veterinary immunology and immunopathology》2007,116(3-4):215-218
Babesia bigemina and Babesia bovis are intra-erythrocytic protozoan parasites transmitted by ticks to cattle in which they induce babesiosis, a disease that resembles human malaria. Anemia, caused by the destruction of non-infected erythrocytes, is a critical feature of the disease. Anti-erythrocyte antibodies could be one of the explanations for such destruction. These antibodies are found in the sera of dogs and mice respectively infected with B. gibsoni and B. rodhaini. However, data concerning the presence of anti-erythrocyte antibodies in the sera of infected cattle are not conclusive. In the present study, we made an attempt to detect anti-erythrocyte antibodies from the sera of cattle naturally infected with B. bigemina. Erythrocytes from a non-infected calf were used in ELISA reaction for the detection of antibodies from samples. Results confirmed the presence of anti-erythrocytes antibodies in higher amounts in the serum of infected cattle. In order to correlate this increment with the parasite, anti-erythrocyte antibodies from the sera from infected calves were purified, coupled to a Sepharose-4B column and than used for anti-idiotypic antibodies purification. These antibodies were found to react with the parasites, suggesting a correlation between both anti-parasite and anti-erythrocyte antibodies. 相似文献
10.
OBJECTIVE: To demonstrate the value of PCR assays to determine the genotypes of Babesia bovis in cattle with clinical signs of babesiosis within 3 weeks after vaccination against tick fever. DESIGN: Samples from 5 cases of babesiosis in cattle soon after vaccination against tick fever were analysed in two PCR assays. PROCEDURE: Parasite DNA was purified from blood taken from cattle with signs of babesiosis within 3 weeks of vaccination against tick fever. DNA was also prepared from the tissues of animals that died of babesiosis. Two PCR assays that amplify repeat sequences of DNA within the B bovis genes, Bv80 and BvVA1, were used to differentiate the genotypes of field isolates and vaccine strains of B bovis. RESULTS: One of the five cases of babesiosis was found to be caused by a vaccine strain, but PCR analyses showed that the predominant isolate in the other four cases was not the vaccine strain. CONCLUSIONS: PCR assays on the DNA of B bovis obtained from the blood or tissues of cattle clinically affected with tick fever within 3 weeks after vaccination are useful to distinguish between vaccine strains and field isolates as the source of infection. 相似文献
11.
The ability of the Babesia equi repetitive probes, pSE2 and pSB20, to detect parasites in blood from experimentally infected, naturally infected and carrier animals was tested using a spot hybridization assay. The clinical course of the experimentally infected horses was monitored using microscopy, indirect fluorescent antibody tests, packed cell volume, temperature and the probe assay. The probes sensitively monitored the parasite level during the development of the disease and correlated well with the other parameters tested. The sensitivity of the probe assay was superior to that of light microscopy, and a parasitaemia equivalent to less than 0.0025% could be detected. Detection of B. equi DNA was possible in all natural cases tested and 20 of the 119 randomly selected horses were identified as carriers of B. equi parasites. Microscopy could identify parasites in only 8 of these carrier animals. These results show that the probes can detect B. equi parasites in carrier animals and that they are suitable for use in a laboratory-based assay for B. equi. 相似文献
12.
The study was carried out to detect Theileria annulata, the causative agent of theileriosis, and Babesia bovis, the causative agent for babesiosis, in Friesian cattle by PCR and conventional blood smear examination. One hundred blood samples obtained from diseased Friesian cattle kept on private livestock farms at Pattoki, District Kasur, Pakistan were collected in addition to 20 blood samples obtained from non-diseased animals. The disease manifestations observed clinically included high fever, swelling of sub mandibular and sub scapular lymph nodes, weakness, increased respiration and pulse, anorexia, loss of condition and rough hair coat. Neurologic sign of in coordination was also seen in weak animals. Signs of lacrimation, pale conjunctiva, diarrhoea, dyspnea and frothy nasal discharge were observed in only one animal. Clinically nine animals showed signs of haemoglobinuria. Diagnosis of bovine theileria and babesia species was based on finding many intraerythrocytic piroplasms of both blood protozoa with clinical signs associated with anaemia, lymph node hyperplasia and haemoglobinuria. One hundred samples of ticks were also collected for identification of vector. Results showed that the prevalence of Hyalomma tick was highest (15%) followed by Boophilus (12%), Haemaphysalis (5%) and Rhipicephalus (3%). The blood smear examination showed 21% (21/100) samples positive for blood parasites out of which 66.6% (14/ 21) samples were positive for theileriosis while 42.8% (9/21) were positive for babesiosis. It was also recorded that 66.66% (6/9) samples were positive for B.bigemina while 33.33% (3/9) were positive for B.bovis. The results showed that 60% (60/100) samples were positive for blood parasites by PCR test. Out of these 60% (36/60) were positive for T.annulata while 33.33% (20/60) were positive for babesia. The specificity and sensitivity of PCR test was higher than blood smear examination. The blood parameters in haemoparasites infection were also analyzed and the results showed significant decrease in total erythrocyte count and haemoglobin while MCV, MCH values increased and MCHC was slightly less than normal indicating macrocytic hypochromic anaemia. 相似文献
13.
Zweygarth E Lopez-Rebollar LM Meyer P 《The Onderstepoort journal of veterinary research》2002,69(3):197-200
Twenty blood samples of zebras (Equus zebra zebra) from the Karoo National Park and the Bontebok National Park in South Africa, all seropositive for Theileria equi, were subjected to in vitro culture to identify carrier animals and to isolate the parasites. Sixteen animals had a detectable parasitaemia in Giemsa-stained blood smears examined before culture initiation, the remaining four animals were identified as T. equi carriers by in vitro culture. Cultures were initiated either in an oxygen-reduced gas mixture or in a 5% CO2-in-air atmosphere. Out of the 20 blood samples, 12 cultures of T. equi and two cultures of T. equi mixed with Babesia caballi were established. None of the four animals seropositive for B. caballi could be identified as carrier animals, whereas two seronegative samples became culture-positive for B. caballi. 相似文献
14.
Live Babesia divergens derived from gerbils were used to vaccinate cattle that had previously been treated with imidocarb dipropionate. Drug doses ranged from 1 to 2 mg/kg and animals were infected subcutaneously three to seven days later. After a further 35 days, vaccinated and control animals were given a heavy heterologous intravenous challenge. This regimen was effective for both avirulent and virulent strains in 12- to 18-month-old cattle. However, at low drug doses some animals reacted to the virulent vaccine strain and at high doses animals infected with the avirulent strain failed to seroconvert although they were still resistant to challenge. The variable infectivity of vaccine strains was a minor problem which can be overcome by strain selection and optimisation of infectivity using gerbils as experimental animals. Gerbils would also be useful as a source of parasites for the further development of in vitro cultures which could ultimately produce the vaccine. 相似文献
15.
Microscopic examination of Giemsa-stained peripheral blood smears collected from three naturally infected dogs originating from Turkey revealed the presence of large (around 4.5-5.0 microm) intraerythrocytic Babesia parasites in all dogs. DNA was extracted from the three infected blood samples and an around 410 bp portion of the 18S rDNA gene of Babesia species was PCR amplified for subsequent molecular characterization. RFLP analysis of the PCR products suggested the presence of the species B. vogeli in all infected dogs and sequencing of the PCR products from two of the three samples revealed 100% identity among the two Turkish isolates. Comparisons with the equivalent 410 bp portions of the 18S rDNA gene of Babesia species confirmed the affiliation of these isolates to the B. vogeli species. This is the first report and molecular characterization of dog infection with a large Babesia species in Turkey. 相似文献
16.
Matsuu A Koshida Y Kawahara M Inoue K Ikadai H Hikasa Y Okano S Higuchi S 《Veterinary parasitology》2004,124(1-2):9-18
The therapeutic efficacy of atovaquone against Babesia gibsoni was examined in three dogs experimentally infected with B. gibsoni isolated from naturally infected dogs in Aomori Prefecture, Japan. Once parasitemia reached 10%, atovaquone was administered orally (30 mg/kg twice daily for 7 days). Within 2 days of atovaquone treatment, the parasite disappeared from blood smears without any clinical side effects. Anemia and thrombocytopenia were significantly improved in all the dogs. However, a polymerase chain reaction assay revealed that a B. gibsoni marker gene was intermittently present in peripheral blood after atovaquone therapy, indicating that the organism had not been eliminated, and parasites reappeared in blood smears 33 days after the last treatment. To investigate the change in sensitivity against atovaquone, an in vitro sensitivity test was performed using peripheral blood obtained from an untreated dog that was infected with the original parasite isolate, and from two of the experimentally infected and atovaquone-treated animals (blood was collected at the time of the post-treatment recurrence of the B. gibsoni infection). Atovaquone was added to the culture medium to final concentrations of 0.1, 1, 10, 100, and 1000 nM. For the untreated parasites, complete growth inhibition occurred at 1000 nM of atovaquone, whereas the recurrent parasites were inhibited by only 39.52 +/- 8.34% and 31.31 +/- 8.14% at this concentration after 48 h of incubation. Thus, the recurring parasites were less sensitive to atovaquone than the untreated originally isolated parasites. 相似文献
17.
Teneral tsetse flies infected with either Trypanosoma brucei or T. vivax were fed on healthy cattle. Blood samples collected daily from the cattle were examined by microscopy for the presence of trypanosomes, in thick smear, thin smear and in the buffy coat (BC). All the cattle fed upon by infected tsetse developed a fluctuating parasitaemia. DNA was extracted from the blood of these cattle and subjected to polymerase chain reaction (PCR) using oligonucleotide primers specific for T. brucei or T. vivax. The PCR products unique to either T. brucei or T. vivax were identified following amplification of DNA from the blood samples of infected cattle, whereas none was detectable in the DNA from the blood of the cattle exposed to non-infected teneral tsetse. In a concurrent set of experiments, one of the oligonucleotide primers in each pair was biotinylated for use in PCR-ELISA to examine all the blood samples with this assay. Both the PCR and the PCR-ELISA revealed trypanosome DNA in 85% of blood samples serially collected from the cattle experimentally infected with T. brucei. In contrast, the parasitological assays showed trypanosomes in only 21% of the samples. In the blood samples from cattle experimentally infected with T. vivax, PCR and PCR-ELISA revealed trypanosome DNA in 93 and 94%, respectively. Microscopy revealed parasites in only 63% of the BCs prepared from these cattle. Neither PCR nor PCR-ELISA detected any trypanosome DNA in blood samples collected from the animals in the trypanosome-free areas. However, both assays revealed the presence of trypanosome DNA in a number of blood samples from cattle in trypanosomosis-endemic areas. 相似文献
18.
D A Christensson 《Acta veterinaria Scandinavica》1989,30(4):453-464
Two groups of calves, 1.5-2 and 7-11 months old respectively, and dairy cows were inoculated i.v. with 3 x 10(7) erythrocytes infected with Babesia divergens. High parasitaemia, fever and other clinical signs of babesiosis occurred among adult animals. A very low parasitaemia and a slightly increased body temperature but no other symptoms occurred in calves. these findings substantiate the conclusion that there exists an inverse age resistance against Babesia divergens. The kinetics of B. divergens IgG antibody formation were similar in all age groups. Consequently this antibody response was not the factor determining the development of the primary parasitaemia and thus the inverse age resistance phenomenon. However, age is not necessarily the only factor involved in the clinical expression of babesiosis. The kinetics of antibody formation was not associated with the intensity of the parasitaemia. In fact only about half the animals had a demonstrable parasitaemia although the antibody responses were similar in all age groups. 相似文献
19.
Agoulon A Malandrin L Lepigeon F Vénisse M Bonnet S Becker CA Hoch T Bastian S Plantard O Beaudeau F 《Veterinary parasitology》2012,185(2-4):101-109
Babesia divergens, transmitted by the tick Ixodes ricinus, is the main agent of bovine piroplasmosis in France. This Apicomplexa often is present in asymptomatic carriers; however, clinical cases are rare. While numerous factors are known to influence tick density, no risk factor of contact with B. divergens has been identified for cattle. Our study aimed to explore whether a Vegetation Index could serve as an indirect indicator of within-herd B. divergens seroprevalence. In February 2007, blood samples were taken from all of the cows in 19 dairy cattle herds in Western France and IFAT serology was performed individually to measure B. divergens seroprevalence. The following spring, I. ricinus nymphs were collected by drag sampling along transects on the vegetation of each farm's pasture perimeters. Tick density was related significantly to a Vegetation Index (V.I., ranging from 1 to 5) that took into account the abundance of trees and bushes on the edge of pastures: most ticks (57%) were found in transects with the highest V.I. (covering 15% of the explored surface in the study area). At the farm level, the proportion of transects presenting I. ricinus nymphs was significantly related to B. divergens seroprevalence: the farms with more than 15% of transects with I. ricinus had a significantly higher risk of high seroprevalence. The proportion of pasture perimeters where the V.I.=5 also was significantly related to B. divergens seroprevalence: the farms where more than 20% of transects had a V.I.=5 had a significantly higher risk of high seroprevalence. Given that the Vegetation Index is a steady indicator of the potential I. ricinus density in the biotope, we recommend that the risk of high B. divergens seroprevalence in cows be evaluated using this tool rather than drag samplings. 相似文献
20.
Evaluation of an enzyme immunoassay for serodiagnosis of infections with Theileria parva and T annulata 总被引：1，自引：0，他引：1
An enzyme linked immunosorbent assay (ELISA) was used to determine antibody levels in cattle infected with Theileria parva and T annulata, using antigens prepared from the intra-erythrocytic piroplasm stage of the parasites. Antibody levels in calves infected with T parva increased from the 16th day after infection to reach peak values at days 28 to 35 and then declined rapidly, but in calves infected with T annulata antibody levels rose steadily up to day 40. Similar patterns of antibody production were shown by indirect fluorescent antibody tests. Sera from animals infected with T parva gave higher ELISA values with the antigen prepared from the homologous parasite species than with the antigen prepared from T annulata, but sera from cattle infected with T annulata gave similar high ELISA values with antigens prepared from both T parva and T annulata. Sera from animals infected with T mutans, T sergenti, T velifera, Babesia divergens, B major and B bovis gave only slight or no cross reactions with the piroplasm antigens, but serum from a calf infected with B bigemina cross reacted at a significant level with both piroplasm antigens. 相似文献