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1.
Diagnosis of Neospora caninum associated bovine abortion is often made by histological examination of fetal tissues, although this procedure is not very sensitive. One hundred and forty-four undiagnosed bovine abortion cases were evaluated for N. caninum associated bovine abortion using a revised diagnostic protocol. As a result, 12 (8.3%) of these previously undiagnosed bovine abortion cases were definitively diagnosed as N. caninum positive. The 12 new positive cases included 7 that had exhibited histological lesions, and 5 that had not exhibited histological lesions when examined prior to this study. None of the 12 cases had been immunohistochemically (IHC) stained prior to this study. Also, IHC staining implemented during this research revealed tachyzoites without associated histological lesions in at least 1 tissue from 69 (47.9%) of 144 aborted bovine fetuses, and positive IHC staining of cytoplasmic N. caninum antigen in macrophages in at least 1 tissue from 44 (30.6%) of 144 aborted bovine fetuses. These results demonstrate the necessity for more aggressive evaluation of bovine fetuses for neosporosis.  相似文献   

2.
The protozoa Neospora caninum is an important cause of bovine abortion world-wide. The objective of this survey was to determine the distribution pattern of infectious abortion in Southern Brazil with special reference to N. caninum infection. A total of 161 bovine aborted fetuses from 149 farms were analysed during a 1.5 year period. The cause of abortion was identified in 51.5% of cases. Overall, 23% (37/161) of the fetuses were considered to be infected with N. caninum. Bacterial infection accounted for 17.4% (28/161) of cases, fungal infection for 3.1% (5/161) of cases and viral aetiology for 1.8% (3/161). Six fetuses had concurrent infection with N. caninum and Leptospira spp. Data from 111 fetuses and the respective aborted cows were analysed to investigate the association between previous abortion and current N. caninum infection. The prevalence of N. caninum-infected fetuses from cows with and without a history of previous abortion was 44% (11/25) and 24.4% (21/86), respectively. Cows aborting a N. caninum-infected fetuses were 2.4 times more likely to have aborted previously than cows aborting for other reasons (95% CI of odds ratio=0.9-6.8, P=0.06).  相似文献   

3.
Forty-six aborted bovine fetuses submitted to the Faculty of Veterinary, Department of Clinical Pathology, Universidade Federal do Rio Grande do Sul, were examined histopathologically. Non-suppurative inflammation was observed mainly in the brain and heart of 22 fetuses. Brain lesions consisted primarily of mononuclear inflammatory cell infiltrates with occasional foci of necrosis. Protozoa that reacted with Neospora caninum antisera were seen in 18 of the 22 (81.8%) brain specimens from fetuses with encephalitis. Blood samples collected from 223 Holstein cows on five dairy herds were tested for N. caninum antibodies by an immunofluorescent antibody technique. These samples were obtained from aborting cattle and normally calving cattle (control group). Overall, 11.2% of cows sampled had N. caninum antibodies at a dilution of 1:200. Seroprevalence was higher (P = 0.0053) in aborting (23.3%) than in non-aborting cows (8.3%). Association between seropositivity to N. caninum and abortion was found, with seropositive cows being 3.3 times more likely to abort than seronegative cows (OR = 3.33; 95% CI: 1.38, 8.062). Additionally, N. caninum antibodies were detected in sera from seven cows that had aborted fetuses with lesions suggestive of protozoal infection. These results suggest that N. caninum is an important cause of abortion in dairy cattle in Rio Grande do Sul State, Brazil.  相似文献   

4.
Brain tissue from 12 aborted bovine fetuses submitted to the Wisconsin Veterinary Diagnostic Laboratory revealed histologic lesions that consisted of glial nodules and variable degrees of mononuclear inflammation, microhemorrhage, neuronal necrosis, and cerebral cortical cavitation. A diagnosis of Bovine herpesvirus 1 (BHV-1) abortion had been made in all of these cases through multiple testing modalities. Brain tissue from 8 of the 12 fetuses was immunohistochemically stained with a monoclonal antibody specific to BHV-1, and, in 5 fetuses, there was positive intralesional staining of neurons, glial cells, and endothelial cells. This preliminary data suggested that herpesviral infection of brain tissue led to the described neurologic lesions. BHV-1 was then amplified from brain tissue in all 12 of the fetuses and was confirmed by partial sequencing of the thymidine kinase and glycoprotein C genes. To the authors' knowledge, neurologic lesions have not previously been described in BHV-1-infected fetuses, nor has BHV-1 previously been identified in bovine fetal brain tissue. The neurologic histopathology attributed to BHV-1 infection in these cases overlaps with the neurologic lesions produced by Neospora caninum, a common etiologic agent of bovine abortion. Therefore, when bovine fetal neurologic lesions are found, both etiologies should be considered and then distinguished by using additional diagnostic tools.  相似文献   

5.
Neospora caninum is one of the most frequent infectious organisms causing abortion in cattle worldwide. The present case-control study was designed to assess the importance of bovine neosporosis for causing abortion in Swiss cattle and to identify selected risk factors. Infection was primarily diagnosed by a N. caninum-specific PCR and serology, complemented with histopathology and immunohistochemistry. A total of 113 case and 113 corresponding control-farms were studied for 1.5 year. During this time period, 242 abortions were reported and referred for bacteriological, virological, parasitological and pathohistological examinations. N. caninum was detected by PCR in the brains of 21% of all aborted fetuses. Microscopic lesions indicative for cerebral protozoa infection were detected in 84% of PCR-positive fetal brains. Bovine viral diarrhea virus (BVDV) was demonstrated in 7% of the cases, and bacterial infections were detected in 4% of the abortions. One or more N. caninum-abortions occurred in 20% of the herds (41 case-farms and 3 control-farms). Serological examination of aborting mother cows revealed a significantly higher percentage of N. caninum-seropositive animals (44%) in comparison to the prevalence in a randomly selected population (12%). However, in eight cases (4% of all investigated abortions) seronegative cows aborted N. caninum PCR-positive fetuses, and in 50 cases the fetus remained negative although the respective mother cow was N. caninum-seropositive. Repetitive serological investigations (at a 3-12 months interval) of 3551 cows from case- and control-farms showed a decrease of the overall N. caninum-seroprevalence from 17 to 12%. Ninety out of 3008 seronegative animals were converted to N. caninum-seropositivity. Conversely, 212 out of 543 initially seropositive animals became seronegative for their second serum sample. The obtained data underlined the importance of N. caninum as a causative agent for abortion in Swiss cattle. Furthermore, PCR was confirmed to be a valuable diagnostic tool for the primary diagnosis of N. caninum in aborted fetuses. On the other hand, the value of serology appears to be hampered by the temporal instability of N. caninum antibody concentrations in adult cattle, including especially seronegativity of some individual animals. Thus, seronegativity in a mother cow or heifer does not exclude N. caninum-associated abortions.  相似文献   

6.
The aim of this study was to determine by nested PCR probe the presence of Neospora caninum in fetal brain tissue from aborted dairy fetuses in Aguascalientes, a state in the central part of Mexico. Forty-four fetal brains from eight dairy farms were analyzed using single tube nested PCR probe with primers NF1, NS2, NR1 and SR1, with histopathology as the reference technique. From the 44 bovine fetuses studied, 35 (80%) were diagnosed as being infected by N. caninum using PCR probe and 20 (45%) were considered positive by histopathology, because they had lesions suggestive of bovine neosporosis. Fair agreement was observed (31%) between both probes. The age of aborting cows ranged from 1.6 to 2.9-year-old in 17 (49%) of the positive cases diagnosed by PCR. Gestational ages of aborted fetuses ranged from <3 to 9 months, with average of 5.6 months, and no statistical significant difference was observed when ages of infected and no infected fetuses were compared (P > 0.05). The frequency of N. caninum positive cases observed could be considered to be higher than other areas of Mexico and other countries.  相似文献   

7.
Abortion in dairy cattle causes considerable economic losses to the dairy industry. Aborted fetuses and samples from the corresponding aborting dams from 12 dairy herds in Beijing were tested for 9 abortifacient infectious pathogens by PCR between 2008 and 2010. From a total of 80 abortion cases collected during this period, infectious agents were detected in 45 (56.3%) cases, 22 (48.9%) of which represented co-infections with two or three infectious agents. The detected pathogens included infectious bovine rhinotracheitis virus (36.3%) and Neospora caninum (31.3%), followed by bovine viral diarrhoea virus (7.5%), Brucella abortus (6.3%), Tritrichomonas foetus (5%) and Toxoplasma gondii (1.3%). Campylobacter fetus, Coxiella burnetii and Chlamydophila psittaci were not detected in any abortion case. Findings from this study indicated that infectious bovine rhinotracheitis virus and Neospora caninum were the main potential causes of abortions in Beijing dairy herds, whereas the bacterial pathogens were not, in contrast to reports from other countries. This is the first study to test nine abortifacient infectious agents by PCR at the same time, and it is also the first time to report the involvement of a variety of infectious agents in bovine abortion cases in China.  相似文献   

8.
Neospora caninum is considered one of the major causes of abortion in cattle in most parts of the world. In this study, the role of N. caninum was investigated in groups of aborted cattle and dairy herds from the west of France. Good correlation was found between parasite DNA detection in fetuses and serologic statuses of dams. In groups with documented abortion status and no antibodies to other pathogens, 17-45% of aborted animals were seropositive for N. caninum, and significant relationship between prevalence of Neospora antibodies and frequency of abortions was found. Neospora-associated abortions were observed all the year round, with a peak in summer. Higher ratios of seropositive abortions were found before the 6th month of gestation. In 12 herds studied in the field, serologic prevalence ranged 6-47%. No difference in age was found between seropositive and seronegative cows. Results indicate that N. caninum is an important and stable cause of abortion in cattle in France.  相似文献   

9.
Abortion outbreaks caused by infection with Neospora caninum in beef cattle have not been well documented. Neospora caninum infection was confirmed in 4 fetuses that were aborted by cattle in a 350-head beef herd; an additional 58 cattle aborted during the next 2.5 months. Overall, 44.4% (157/354) of the cattle in the herd did not become pregnant or experienced fetal loss during this period. Initially, 81.3% (282/347) of the herd was seropositive for antibodies to N caninum, and seropositive cows were 6.2 times as likely to not be pregnant as were seronegative cows. Other potential causes of abortion were not identified in this herd. Following the outbreak, few cattle in the herd or in a second exposed herd seroconverted, but high antibody titers persisted in most seropositive cattle through the end of the calving season. Evidence of cow-to-fetus transmission of the organism was detected in > 82% of seropositive cows.  相似文献   

10.
Neospora caninum was detected by means of PCR in the brain of 4 out of 20 aborted fetuses in a flock of 117 sheep exhibiting a persistent abortion problem, and N. caninum tissue cysts were furthermore found in encephalitic lesions in one of the PCR-positive fetuses. Toxoplasma gondii was detected as aborting agent in another 3 out of 20 fetuses. Antibodies to N. caninum (by indirect fluorescence antibody test (IFAT)) were found in 10.3% of 117 ewes and antibodies for T. gondii were found in 97.4% of 117 ewes. Other organisms associated with abortion were Chlamydia psittaci in three fetuses and Pasteurella multocida in one fetus. This is the first report of N. caninum associated abortion in naturally infected sheep.  相似文献   

11.
Neospora caninum is a protozoan that causes abortion in cattle. The dog has recently been identified as a definitive host for N. caninum. To verify if bovine fetuses can infect dogs, nine 2-4-month-old dogs were fed bovine fetuses naturally infected by N. caninum. None of the dogs excreted oocysts, seroconverted, had clinical signs or lesions compatible with N. caninum infection. Additional studies will be necessary to determine the natural mode of infection of dogs by N. caninum.  相似文献   

12.
Ninety-five aborted bovine fetuses received from California dairies over a 4.5-year period had histologic lesions of focal encephalitis. Protozoa that reacted with Neospora caninum antiserum were detected in the brain of 88 of these fetuses and in the heart of 1 fetus. Sarcocystis spp schizonts were seen in the vascular endothelium of 1 fetus. It was concluded that a Neospora-like cyst-forming coccidian may be a major cause of abortion in California dairy cattle.  相似文献   

13.
The protozoan parasite Neospora caninum is one of the most important infectious abortion causes in cattle worldwide. In a Swiss case-control-study we investigated 113 abortion problem farms and 113 control farms. It was possible to detect N. caninum in 21% of 242 investigated aborted fetuses by PCR upon brain samples. Eighty-four % of mothers aborting N. caninum positive fetuses were serologically positive for this parasite. The seroprevalence for N. caninum of all aborting mothers was 44%. Within a period of 3 to 12 months 4,505 cattle from the participating farms were investigated serologically at two different time points. Strong fluctuations of the specific antibody concentration could be observed, resulting in a conversion to seronegativity in the second blood sample in 39% of formerly seropositive animals. Eighteen months after the end of the study, 42 case- and 42 controlfarms were questioned about their present abortion-status. Analysis of the questionnaire revealed that 80% of the former abortion problem farms observed an improvement of the situation. However, in 43% of those farms no preventive measures had been taken and no significant differences in hygiene, forage and animal turnover could be observed between case- and control-farms. Additionally, no significant differences were detected concerning risk factors such as the presence of farm dogs and the disposal procedure for placental and fetal material.  相似文献   

14.
The aim of the present work was to evaluate the role of Neospora caninum and Toxoplasma gondii infections in spontaneous bovine abortions in Argentina. Based on histopathological results, 70 presumptive cases of apicomplexan protozoal abortion from a total of 666 cases of spontaneous bovine abortion submitted to the National Institute of Agrarian Technology, Balcarce, from 1999 to 2007 were included in this study. N. caninum infection was diagnosed by an indirect fluorescent antibody test (IFAT), by immunohistochemistry (IHC) and by nested-PCR. T. gondii infection also was diagnosed by nested-PCR. DNA from fetuses was extracted primarily from CNS tissues. Heart, liver, muscle and/or placenta were processed when nervous tissue was not available. Sixty-six (9.9%) fetuses were positive by at least one technique (IFAT, IHC or nested-PCR) for N. caninum infection. Overall, there was poor agreement among results obtained by these diagnostic techniques. In contrast, no Toxoplasma-infection was detected in any aborted bovine fetus.  相似文献   

15.
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16.
In vitro isolation and characterization of bovine Neospora caninum in Korea   总被引：5，自引：0，他引：5  
The brains of nine aborted bovine fetuses and two newborn calves born from dams suspected to be infected with Neospora caninum were homogenized and inoculated into Vero cells. All fetuses and calves were from cows determined as seropositive to N. caninum by an IFA test. Sera and thoracic fluids of all fetuses and calves also revealed high antibody titer to N. caninum by IFAT ranging from 1:800 to 1:3200. N. caninum was isolated from the brains of one aborted fetus and one newborn calf when the brain homogenates were grown continuously in Vero cell culture. N. caninum tachyzoites, giemsa-positive, were first observed on Days 45 and 56 postinoculation in the newborn calf and the aborted fetus, respectively. The isolates (KBA-1 and KBA-2) were morphologically and ultrastructurally similar to previously published Neospora isolates. The isolated parasites were confirmed as N. caninum by means of the antigenic reactivities, immunostaining, PCR and southern blotting, and electron microscopy.  相似文献   

17.
An enzyme-linked immunosorbent assay (ELISA) was established to measure the avidity of bovine IgG directed against p38, a surface antigen (NCSRS2) of Neospora caninum tachyzoites. In the sera of dams intravenously infected with N. caninum NC-1, the p38-specific avidity increased from initially below 40% up to avidity indices between 50 and 80% after days 23 and 91 p.i. The p38-avidity-ELISA was used to examine various herds that had experienced endemic and epidemic N. caninum-associated bovine abortions. In herds with endemic abortion, generally high avidity indices of N. caninum-specific IgG were detected. This finding and the observation of an association between the seropositivity of dams and that of their offspring suggested a predominantly vertical transmission of the parasite among the animals of these herds, thus indicating chronic infection of these cattle. In contrast, for herds experiencing epidemic abortion: (i) an association regarding seropositivity of dams and their daughters could not be shown and (ii) a generally low avidity of p38-specific IgG in the sera from aborting dams was determined. This indicates recent postnatal transmission of N. caninum in these herds. A linear regression model explaining the avidity of p38-specific IgG was significantly influenced by the time span between sampling and the occurrence of the first abortion of the epidemic in herds with an N. caninum-associated abortion storm. Another factor significantly contributing to the model was the proportion of dams at risk that had aborted in the herds (i.e. the severity of the abortion epidemic). A possible explanation for this observation is that herds experiencing heavy abortion are sampled earlier after the onset of the epidemic than others that have a less severe abortion storm.  相似文献   

18.
During 2003-2005, 399 abortion samples (315 fetuses and 84 placentae) were collected from 107 ovine and caprine farms in northern Sardinia. Tissues from aborted fetuses and placentae were examined by PCR assay to detect DNA from Coxiella burnetii, Chlamydophila abortus, Salmonella enterica Serovar abortusovis, Toxoplasma gondii, and Neospora caninum. The DNA from at least 1 of these 5 infectious agents was amplified in 41% of ovine fetuses, while only 17% of the caprine fetuses yielded a positive amplification result for at least 1 of the 5 agents. Out of a total of 366 ovine aborted samples, T. gondii DNA was detected most frequently (18.1% of fetuses and 13.1% of placentae), followed by S. abortusovis (13% of fetuses and 14.4% of placentae), C. burnetii (10.9% of fetuses, of 9.2% placentae), C. abortus (2.4% of fetuses, 6.5% of placentae), and N. caninum (2% of placentae). In 33 fetuses and 9 placentae, the simultaneous presence of pathogens with different associations was detected. Out of a total of 31 caprine aborted samples, T. gondii was detected most frequently (13% of fetuses and 25% of placentae), followed by C. abortus (12.5% of placentae), C. burnetii (12.5% of placentae), and N. caninum (8.6%).  相似文献   

19.
Neospora caninum, an apicomplexan protozoan parasite, is recognized as a major cause of abortion in cattle while limited information is presently available on association between equine Neospora infections and abortions. The aim of the present study was to document prevalence of antibodies against Neospora sp. in aborted mares as a clue to the role of N. caninum in mare reproductive failure in Normandy, France. Using an agglutination test, the number of animals with elevated (>80) anti-Neospora sp. antibody titer was higher in a group of 54 aborted mares than in randomly chosen groups of 45 mares and 76 horses sampled for equine arteritis virus and Fasciola hepatica antibodies, respectively (P<0.001). N. caninum DNA was found in 3/91 fetal brains, 2/77 fetal hearts, and 1/1 placenta, and present in both brains and hearts of two fetuses. In 13 cases for which both mare serum and fetus were available, no fetal N. caninum amplification product was present while a large variation of maternal antibody titers was found. Data prompt at additional surveys of association between equine reproductive failure and Neospora sp. infection.  相似文献   

20.
Diagnosis of the causes of bovine and ovine abortion is difficult and frustrating and requires a systematic and thorough approach. Laboratory assistance is required in all cases. Herd and individual histories occasionally help, as does knowledge of the gestational age and autolytic condition of the fetus when aborted. Tissues from mummified fetuses should be cultured and examined by fluorescent antibody techniques for viruses. The placental tissue from mummified fetuses should be examined for fungi and lesions. Lung, liver, kidney, spleen, abomasal content, body cavity fluid or serum, and fetal placenta from all but completely mummified fetuses should be submitted to a diagnostic laboratory.  相似文献   

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