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1.
In a dairy herd experiencing an abortion outbreak, 49% of the 119 cows were positive for Neospora caninum antibodies and the remaining 51% were seronegative. Using immunohistochemical analysis of foetal brain tissue, Neospora cysts and bradyzoite clusters were identified in two of the 15 aborted foetuses submitted for testing. Other agents that commonly cause abortions were not found. These results, coupled with neurological clinical symptoms in new-born calves, implicated N. caninum as the major cause of abortions in this dairy herd. This is the first report that associates N. caninum infection with bovine abortions in Portugal.  相似文献   

2.
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   

3.
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   

4.
An outbreak of Neospora caninum-associated abortion occurred in a South Carolina dairy wherein greater than 10% of the herd aborted over a 4-month period. Of the total number of cows at mid-late gestation, nearly 40% (28/71) aborted while the remaining 60% (43/71) gave birth to normal calves. Immunohistochemical examination of brain tissue from a subset of aborted fetuses confirmed N. caninum as the causative agent of abortion in these animals. A variety of serological assays, including indirect fluorescence antibody test (IFAT), recombinant enzyme-linked immunosorbent assay (rELISA), ISCOM-ELISA, avidity ELISA, and Neospora agglutination test (NAT), were used to evaluate sera collected during the outbreak from 240 cows for antibodies to N. caninum. IFAT and ISCOM-ELISA testing showed that nearly 80% of the dairy cows had antibodies to N. caninum. NAT and rELISA had similar levels of seropositivity relative to IFAT and ISCOM-ELISA, but the percentage of positive sera was dependent on the cut-off value chosen. As indicated by kappa coefficient statistical analysis, ISCOM-ELISA and IFAT exhibited the highest level of agreement in identifying N. caninum-positive and -negative cows. A decrease in the percentage of seropositive cows as determined by ISCOM-ELISA and IFAT with increasing cow age was noted. However, no significant difference was observed between cow age and abortion status. In addition to these tests, an avidity ELISA was performed on all sera with high (> or =0.4) ISCOM-ELISA readings. Avidity index (AI) increased with time post-abortion suggesting that most abortions were due to recent N. caninum infection. Of the cows at risk for abortion, the mean serological AI of aborting cows was significantly lower (P<0.05) than mean serological AI of non-aborting cows.  相似文献   

5.
Toxoplasma gondii infection was diagnosed in a full term stillborn reindeer (Rangifer tarandus) fetus. The fetus had encephalitis and placentitis associated with T. gondii. Tissue cysts were identified histologically in sections of brain and tachyzoites were present in placenta and the myocardium. Protozoa in the brain, heart, and placenta stained positively with T. gondii antibodies, but not with Neospora caninum antibodies in an immunohistochemical test. The dam of the fetus had a 1:12,800 titer to T. gondii in the modified agglutination test employing whole tachyzoites and mercaptoethanol. This is the first confirmed report of T. gondii infection in reindeer.  相似文献   

6.
First Israeli Neospora caninum isolates were obtained from brain tissues of aborted fetuses (NcIs491 and NcIs580) from dairy farms endemic for neosporosis and maintaining cattle on zero grazing. Tissues from different parts of the fetus brains were used to infect Vero cells. Tachyzoites of N. caninum were first observed in cultures from days 30 and 32 after infection. To confirm the identity of the isolated parasites, DNA extracts from brains and cultures were tested by PCR with specific primers based on the Nc5 gene. Specific fragments were amplified by PCR from infected cultures of both fetuses on day 25. Susceptible seronegative gerbils (Meriones tristrami) were inoculated intraperitoneally with 10(3) to 10(5) tenfold dilutions of subculture tachyzoites. The inoculated gerbils developed specific antibodies to N. caninum, with end-point serum dilution of 1:4096 in the IFA assay, whereas no neurological signs or deaths were seen during 4 months of observation.  相似文献   

7.
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   

8.
Sera from 76 horses from Argentina were examined for antibodies to Sarcocystis neurona, Toxoplasma gondii and Neospora caninum. Antibodies to S. neurona were found in 27 (35.5%) of 76 horses using immunoblots with culture derived merozoites as antigen. Antibodies to T. gondii were found in 10 (13.1%) of 76 horses by using the modified agglutination test with formalin-fixed tachyzoites and mercaptoethanol; titers were 1:25 (two horses), 1:50 (six horses), 1:100 (two horses), and 1:200 (one horse). Antibodies to N. caninum were not found in any of the 76 horses by the use of N. caninum agglutination test. This is the first report of S. neurona infection in horses in Argentina.  相似文献   

9.
Neospora caninum was isolated from the brain of a 2-year-old dairy cow that had aborted confirmed N. caninum-infected fetuses on two occasions. The cow had an indirect fluorescent antibody titer of 1:1600 to N. caninum. The cow was killed 24 days after its second abortion and the brain was bioassayed for N. caninum in nude mice. Multifocal areas of perivascular cuffing and glial nodules were observed in the cerebrum and mesencephalon of the cow, but N. caninum was not identified in histological sections of the brain. All three nude mice inoculated with brain homogenate of the cow, developed emaciation and paralysis. Microscopical examination of the nude mice revealed systemic N. caninum infection with demonstrable tachyzoites in various organs. The parasites isolated from fresh mouse brain were transferred successfully into Vero cell cultures. PCR procedure on the purified tachyzoites obtained from the Vero cell cultures amplified the specific DNA sequence for N. caninum.  相似文献   

10.
Serology for Neospora caninum was undertaken using direct ELISAs on sera from 660 aborted sheep and 454 breeding sows, which had aborted or were considered infertile. All ovine sera were further tested by indirect fluorescent antibody test (IFAT) for N. caninum, and a latex agglutination test (LAT) for Toxoplasma gondii was performed on 423 of the samples, including all those positive by ELISA. ELISA-positive porcine sera were tested by IFAT and an inhibition ELISA for antibodies to N. caninum and by LAT for T. gondii. Only 3 (0.45%) of the ovine sera were seropositive for N. caninum by both ELISA and IFAT whereas although 40 porcine sera were seropositive by ELISA all were negative by IFAT. The results suggest that environmental exposure to N. caninum occurs rarely in sheep and pigs.  相似文献   

11.
Sera from 800 asymptomatic horses were examined for the presence of antibodies to Neospora caninum by immunofluorescence antibody test (IFAT). The presence of antibodies to N. caninum was also tested in sera from 52 mares that had aborted and 40 horses exhibiting neurological signs. A total of 95 (11.9%) of the 800 sera had antibodies for Neospora. Significantly higher seropositivity was obtained from horses that had neurological signs (21.2%) and from aborted mares (37.5%). There was significant linear-by-linear association between age and seropositivity. This is the first serologic survey for Neospora spp. antibodies performed on horses from the Middle East and the first to report significant difference in seropositivity between asymptomatic horses and horses exhibiting neurological signs.  相似文献   

12.
Three Jersey cows were inoculated SC and IM with 26 million Neospora caninum tachyzoites at 129 (cow 1), 126 (cow 2), and 81 (cow 3) days after mating. Cows remained clinically normal for at least 1 month after inoculation of N caninum. Cow 1 was euthanatized 32 days after inoculation because of gangrenous mastitis. Cow 1 had a live fetus with no gross lesions; however, microscopic lesions were seen in the fetus and consisted of severe nonsuppurative necrotizing encephalitis of the cerebral white matter. Neospora caninum was identified in lesions by staining with anti-N caninum serum in an immunohistochemical test, by bioassays in mice, and by inoculation of bovine monocyte cultures with fetal tissue homogenate. Neither N caninum nor lesions were associated with infection with the protozoon identified in tissues of cow 1. Cows 2 and 3 aborted small autolysed fetuses 101 and 74 days, respectively, after inoculation with N caninum; the fetuses and attached placenta were unsuitable for laboratory investigations. Cows 2 and 3 remained clinically normal 4 months after abortion. Results of this study indicated that N caninum can be transmitted transplacentally in cattle.  相似文献   

13.
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   

14.
Seroprevalence of Neospora caninum in dairy cattle in Bahia, Brazil.   总被引：2，自引：0，他引：2  
Sera collected from 447 dairy cattle on 14 dairy farms were tested for Neospora caninum antibodies by use of an immunofluorescent antibody technique. Positive reactions with titres > or =1:200 were found in 63 (14.09%) of animals. Neospora positive sera were also tested for Toxoplasma gondii antibodies by using a commercial latex agglutination test. Antibodies to T. gondii were detected in 3 (4.76%) of 63 N. caninum positive sera. These results indicate that N. caninum infection is widespread among dairy cattle in Bahia state.  相似文献   

15.
Domestic dog (Canis domesticus) and the coyote (Canis latrans) are the only known definitive hosts for the protozoan Neospora caninum that causes abortion in dairy cattle. In the present study, antibodies to N. caninum were sought in three species of wild canids, Cerdocyon thous, Lycalopex gymnocercus and Dusicyon vetulus from Brazil. Antibodies to N. caninum were assayed by the indirect fluorescent antibody test (IFAT) and the Neospora agglutination test (NAT). N. caninum antibodies were found in five of 12 L. gymnocercus with IFAT titers of 1:50 in three, 1:100 in one, and 1:1600 in one, and NAT titers of 1:40, 1:80, 1:160, 1:320, and 1:640 in five animals. Antibodies to N. caninum were found in four of 15 C. thous with IFAT titers of 1:50 in one, and 1:100 in three, and NAT titer of 1:40 in one animal. All 30 D. ventulus were seronegative by IFAT and NAT.  相似文献   

16.
Sera were collected from 490 dogs from north-west Italy. One hundred and eighty-eight dogs were urban, while 302 dogs were rural. Among the latter, 190 were shepherd dogs and 112 were cattle farm dogs. Sera were tested for the presence of antibodies against Neospora caninum using the Neospora agglutination test. Seroprevalence at 1/40, 1/80, 1/160 dilution titres was significantly higher in rural (36.4%, 19.5%, 9.9% respectively) than in urban dogs (20.2%, 10.6%, 4.8% respectively). Seroprevalence did not differ significantly in males and females. In shepherd dogs, prevalence increased according to dogs' age, thus suggesting a post-natal exposure by horizontal transmission. The observed higher seroprevalence in rural dogs suggests the importance of lifestyle and alimentary habits (i.e. aborted foetuses, placentas and small mammals) in the acquisition of N. caninum infection. Our results confirm that dogs are exposed to N. caninum and play an important role in the epidemiology of N. caninum.  相似文献   

17.
Antibodies to Neospora caninum were assayed in sera of 222 female water buffaloes from Ribeira Valley of S?o Paulo State, Brazil, using an indirect fluorescent antibody test (IFAT) and Neospora agglutination test (NAT). IFAT antibodies were found in 64% of buffaloes with titers of 1:25 (42 buffaloes), 1:50 (53 buffaloes), 1:100 (31 buffaloes), 1:200 (10 buffaloes), 1:400 (3 buffaloes), or > or =1:800 (3 buffaloes). NAT antibodies were found in 53% of buffaloes; in titers of 1:40 in 52 buffaloes, 1:80 in 27 buffaloes, 1:160 in 21 buffaloes, and > or =1:320 in 17 buffaloes. Results indicate a high prevalence of N. caninum exposure in water buffaloes in Brazil and warrant an investigation of the role of N. caninum as an abortifacient in water buffaloes.  相似文献   

18.
A serological survey for antibodies against Neospora caninum in cattle, goats and farm dogs in Taiwan was carried out. Sera of 613 cattle from 25 dairy farms, 24 goats from six goat farms and 13 dogs from six dairy cattle farms were tested for antibodies against N. caninum using indirect fluorescence antibody test (IFAT). The same sera were also tested for antibodies against Toxoplasma gondii using latex agglutination test. Of the 613 cattle sera, 44.9% (275/613) were found to have antibodies against N. caninum. Among these 275 positive cattle, 77 also possessed antibodies against T. gondii. Nevertheless, 92 cattle which were negative for N. caninum showed antibodies against T. gondii. Of the 24 goat sera tested, none was found to be positive for N. caninum but 50% (12/24) were positive for T. gondii. Of the 13 farm dogs tested, three were found to possess antibodies against N. caninum, two of which tested negative for T. gondii antibodies. Besides sera, antibodies to N. caninum in cattle could be observed in the milk, vaginal secretion and saliva. However, the order of higher frequency of antibodies detection is in sera, milk, vaginal secretion and saliva. This is the first demonstration of the presence of antibodies to N. caninum in vaginal secretion and saliva of cattle. A 50microm cyst was observed in the brain of one of the 13 prednisolone-treated SPF ICR mice which had been peritoneally inoculated 4 months earlier with the brain homogenate of a serologically N. caninum positive but T. gondii negative cattle. Thus, we have confirmed for the first time the presence of N. caninum in Taiwan and also observed that it is widespread among dairy cattle and farm dogs.  相似文献   

19.
Zhang W  Deng C  Liu Q  Liu J  Wang M  Tian KG  Yu XL  Hu DM 《Veterinary parasitology》2007,149(1-2):72-76
The first identification of Neospora caninum infection in the tissues of aborted bovine foetuses in China is reported. Aborted foetuses were collected from 16 dams, and 12 of the dams had high serum antibody titres to N. caninum determined using an ELISA test kit. The Nc-5 gene of N. caninum was amplified from DNA samples extracted from brains of four aborted foetuses using a Neospora-specific PCR assay, confirming N. caninum infection in the aborted foetuses. Histology and immunohistochemistry showed thick-walled (3 microm) tissue cyst in 25 microm diameter in the brain of one foetus. Non-suppurative encephalomyelitis, focal haemorrhage, hepatic lesions consisted of lymphocyte infiltration and haemorrhage were also found in the heart and lung of the foetus. Thus, we have confirmed for the first time the infection of N. caninum in aborted foetuses of cattle in the People's Republic of China.  相似文献   

20.
Neospora caninum was isolated from a naturally infected sheep from Brazil by bioassay in dogs. Approximately 70g of brain from each of two 4-month-old sheep with indirect fluorescent antibodies (>or=1:50) to N. caninum was offered to a different IFAT negative dog (Sheep n. 302, IFAT 1:400-Dog 1 and Sheep n. 342, IFAT 1:50-Dog 2). Parasite DNA was detected in both sheep brains using a PCR targeting the Nc-5 gene of N. caninum. Shedding of Neospora-like oocysts was noticed only in Dog 1, from 10 days post-inoculation (PI) to 25 days PI (a total of approximately 27,600 oocysts). Seventy days after infection, Dog 1 was euthanized and brain/cerebellum and medulla were collected and submitted to molecular methods, as were the oocysts, to confirm the identity of the isolate. Serum samples collected weekly from both dogs from the infection to the end of the experimental period had no antibodies anti-N. caninum by IFAT (<1:50). Oocysts, brain/cerebellum and medulla specimens of Dog 1 proved positive by a PCR assay targeting the Nc-5 gene of N. caninum. In addition, the oocysts have the DNA amplified by a PCR based on primers directed to the common toxoplasmatiid ITS1 sequence. The PCR products of ITS1 were sequenced, confirming again the isolate as N. caninum. Oocysts were also orally inoculated in two Swiss white mice two Mongolian gerbils (Meriones ungulatus) and two large vesper mice (Calomys callosus) (10(3)oocysts/animal). The rodents were sacrificed 2 months PI, and fresh preparations of brains showed Neospora thick-walled cysts in gerbil brains, but molecular detection using the Nc-5 PCR assay revealed DNA parasite in gerbil and also C. callosus brains. This is the first report of isolation and sequencing of N. caninum from a Brazilian sheep and the first report of molecular detection of N. caninum from C. callosus.  相似文献   

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