Seroprevalence of antibody to NcSAG1 antigen of Neospora caninum in cattle from Western Java,Indonesia

Neospora caninum can cause fetal abortion and neonatal mortality in cattle, and is a cause of economic concern worldwide. This study aimed to determine the prevalence of Neospora caninum-specific antibodies in cattle from Western Java, Indonesia. Serum samples from 991 cattle from 21 locations were tested for antibodies to N. caninum by using an enzyme-linked immunosorbent assay (ELISA) on the basis of recombinant NcSAG1. The overall seroprevalence was 16.6%, ranging from 0 to 87.5% in the sampled locations. The results of this study indicate latent infection rates of sampled animals were different in each location. Further studies are necessary to elucidate the relationship between N. caninum infection and abortion in cattle, and to identify risk factors for infection in high-prevalence environments.     

Presence of Neospora caninum specific antibodies in three dairy farms in Georgia and two in Texas

Neospora caninum is known to cause abortion in cattle. This study demonstrated the presence of specific IgG to Neospora in milk and serum samples obtained from three dairy farms in Georgia and two in Texas. Samples from four hundred fourteen dairy cows were examined using a western blot assay of which 362 were milk and 87 were serum. Samples with antibodies to Neospora were identified in 32.1% (105/327) of the examined animals in Georgia, whereas in Texas it was identified in 10.3% (9/87). Positive Georgia samples were found in 24.4% from farm A (28/115), 21.6% from farm B (30/139), and 64.4% from farm C (47/73). In Texas, 13.5% (7/52) of animals in farm D and 5.71% (2/35) from farm E also had specific antibodies to Neospora. The number of animals from Georgia dairy farms with antibodies to Neospora was significantly higher than the Texas dairy farms. This may be related to the age of the animals examined in this study (more than 2 years old). Antibodies present in sera had excellent agreement with the antibodies present in milk. Collection of milk samples for serological testing is easier and less invasive than obtaining bovine sera, therefore offering an alternative for animal testing.     

新疆伊犁部分地区奶牛新孢子虫病血清学调查

用新孢子虫地方虫株SRS2重组抗原作为ELISA诊断抗原,对新疆伊犁部分地区奶牛新孢子虫病进行了血清学调查。结果表明,从101份奶牛血清样品中检出牛新孢子虫抗体阳性血清12份,阳性率为11.9%,各种年龄段的奶牛均可感染,经统计学分析,差异不显著(P0.05)。本次血清学调查为新疆伊犁地区有效地控制该病的发生和蔓延提供了重要的理论依据。     

Evidence of mixed infection of peste des petits ruminants virus and bluetongue virus in a flock of goats as confirmed by detection of antigen, antibody and nucleic acid of both the viruses

A mixed infection with peste des petits ruminants virus (PPRV) and bluetongue virus (BTV) occurred in goats which exhibited symptoms characteristic of PPR. A number of samples were collected from ailing or dead goats for labrotory diagnosis. Antibody to BTV and PPRV was detected in sera samples by competitive ELISA. No PPRV antigen was detected in tissue samples like lung and spleen, however, presence of PPRV antigen in some sera samples was confirmed by sandwich ELISA. All the blood samples collected from the ailing animals were found positive for BTV antigen by a sandwich ELISA. BTV- and PPRV nucleic acids were amplified from the pooled blood and tissue samples respectively by RT-PCR assays. The identity of the amplicons was confirmed by cloning and sequencing. All these tests confirm that the goats were infected with PPRV and BTV simultaneously. Isolation of viruses from the clinical samples is underway.     

Prevalence and mortality rate of peste des petitis ruminant (ppr): possible association with abortion in goat

Present study was designed to investigate the prevalence and mortality (%) caused by Peste des Petitis Ruminant (PPR) and its possible association with abortion in goat flocks at different areas of Pakistan. A total of 140 animals were samples in the population of 650 which was having 185 deaths (Mortality rate = 28 %) from three different regions of the country. There were 58 abortions in the 140 pregnant goats of above said population One hundred & ten (110) serum samples from diseased, recovered and apparently healthy animals were tested for the presence of PPR antibodies by competitive ELISA (c ELISA). Eighty-four (84) animals were positive for PPR antibodies whereas in apparently healthy adult goats in the same flock, no PPR antibodies were detected. Twenty-four (24) tissue samples collected from the dead animals and six samples from aborted fetus were tested for the presence of PPR antigen by Immuno-capture ELISA (Ic ELISA). Nineteen (19) out of thirty (30) organ samples mainly from lung, spleen, lymph node were found positive for PPR antigen but negative from lungs of aborted fetus. There was a high rate of abortions (28–45 %) in each of the outbreak and it was highest in the outbreak of Golra Sharif, Islamabad (No. = 21 in total population of 100). As the serum samples from the aborted dams were found positive for PPR antibodies so the study provides the possible association of mortality and prevalence of PPR disease with high rate of abortions in goat.     

Serological analysis of calves experimentally infected with Neospora caninum: a 1-year study

A serological study was conducted with calves experimentally infected with the protozoan parasite Neospora caninum. The animals were inoculated with either a low or high dose of N. caninum tachyzoites and temperature responses monitored daily for the first 2 weeks after inoculation. Blood samples were collected before inoculation, and at regular intervals thereafter for 1 year. Serological analysis was achieved using an indirect fluorescent antibody test (IFAT), an enzyme-linked immunosorbent assay (ELISA) and an IgG avidity ELISA.Injection of Neospora produced a significant rise in rectal temperature in the high dose group. In addition, the lymph node draining the site of inoculation increased in size following injection in all animals, in both infected groups, before returning to normal by day 14 after injection. Both groups given N. caninum produced specific antibody that was detected by the IFAT and the ELISA, which remained elevated for the 12-month duration of the experiment. The specific Neospora antibodies produced did not cross-react in an IFAT for the detection of antibodies to Toxoplasma gondii. IgG avidity increased 2 weeks after inoculation, in both infected groups, until week 12 when infection was well established. There was a little difference between the two infected dose groups. This study demonstrates that the two different doses of N. caninum produced a similar antibody response, and that the higher dose also induced a febrile reaction. The IgG avidity ELISA was successful at distinguishing between recent and long-standing infection in this study. However, in both groups, there was fluctuation in the levels of specific antibody throughout the yearlong study, which accords with similar experiments in pregnant cattle, where it has been suggested that fluctuation may indicate periodic recrudescence of infection and a re-stimulation of antibody production by antigen.     

青海省乌兰县牧羊犬犬新孢子虫病的血清学调查

用犬新孢子虫的重组蛋白GST-NcSAG1t作为ELISA诊断抗原,对青海省乌兰县的部分牧羊犬进行了犬新孢子虫病的血清学调查。经过对所收集的80份牧羊犬血清的检测,共检出犬新孢子虫病阳性血清25份,阳性率为31.25%。结果表明青海省乌兰地区的牧羊犬中存在犬新孢子虫感染。     

青海省海西地区山羊和绵羊犬新孢子虫病的血清学调查

用犬新孢子虫的重组蛋白GST-NcSAG1t作为ELISA诊断抗原,进行了青海省海西地区山羊和绵羊群中犬新孢子虫病的血清学调查。经过对所收集的120份绵羊血清和531份山羊血清抗体的检测,共检出绵羊阳性血清10份,山羊阳性血清36份,其阳性率分别为8.33%和6.78%。说明青海省海西地区的绵羊和山羊群中存在犬新孢子虫的感染。     

Use of an enzyme-linked immunosorbent assay in bulk milk to estimate the prevalence of Neospora caninum on dairy farms in Prince Edward Island, Canada

This study evaluated the use of bulk milk as a diagnostic tool for estimation of herd-level Neospora caninum exposure in Atlantic Canada; it was used to estimate the prevalence of dairy farms with a within-herd N. caninum-seroprevalence > or = 15% in Prince Edward Island (PEI). The variation over time of N. caninum antibodies in bulk milk is also reported. Skimmed bulk milk and individual serum samples were analyzed for N. caninum antibodies by using an enzyme-linked immunosorbent assay (ELISA). Bulk milk samples were collected in May 2004 (n = 235), May 2005 (n = 189), and June 2005 (n = 235). The prevalence of dairy farms with a within-herd seroprevalence > or = 15% on PEI was 6.4% in May 2004. In May and June 2005, respectively, 10.1% and 10.2% of farms had a > or = 15% within-herd seroprevalence. In 11 farms that were considered positive based on bulk milk samples, blood samples were collected from all adult cows in September 2005, in conjunction with a 4th bulk milk sample on the same day. The correlation coefficient between serology and bulk milk ELISA was 0.87. The results of this study demonstrate that the prevalence of N. caninum in dairy farms can be estimated by using a bulk milk ELISA.     

Prevalence of Neospora hughesi and Sarcocystis neurona antibodies in horses from various geographical locations

Parasite-specific antibody responses to Neospora antigens were detected using the immunofluorescent antibody test (IFAT) and immunoblot analysis in select equine populations. For comparison, a naturally infected Neospora hughesi horse and an experimentally inoculated Neospora caninum horse were used. In addition, all samples were tested for antibodies to Sarcocystis neurona by immunoblot analysis. A total of 208 samples was evaluated. The equine populations were derived from five distinct geographic regions. Locations were selected based on distribution of Didelphis virginiana, the native North American opossum which serves as the definitive host for S. neurona. Only 11% of the samples that had positive titers of 1:100 using the IFAT were also positive for antibodies by immunoblot analysis in this study. Overall, there was a 2% seroprevalence for Neospora antibodies in all horses tested based on immunoblot analysis described. The seroprevalence for S. neurona antibodies varied from 0% (New Zealand and Montana) to 54% (Missouri). We concluded that, in testing for antibodies against Neospora antigens using either IFAT or immunoblot analysis, as described, positive results should not be attributed to the presence of antibodies to S. neurona.     

Neospora caninum antibodies detected in Midwestern white-tailed deer (Odocoileus virginianus) by Western blot and ELISA

White-tailed deer (Odocoileus virginianus) serve to maintain the Neospora caninum life cycle in the wild. Sera from white-tailed deer from south central Wisconsin and southeastern Missouri, USA were tested for antibodies to N. caninum by Western blot analyses and two indirect ELISAs. Seroreactivity against N. caninum surface antigens was observed in 30 of 147 (20%) of WI deer and 11 of 23 (48%) of MO deer using Western blot analysis. Compared to Western blot, the two indirect ELISAs were found to be uninformative due to degradation of the field-collected samples. The results indicate the existence of N. caninum antibodies in MO and WI deer, and that Western blot is superior to ELISA for serologic testing when using degraded blood samples collected from deer carcasses.     

A long-term study of Neospora caninum infection in a Swedish dairy herd

A longitudinal study was performed in a Swedish dairy herd where Neospora caninum had been isolated from a stillborn calf. Starting in autumn 1994, blood samples from all female animals in the herd were collected once yearly until 1999. The sera were analysed for presence of IgG1 antibodies to N. caninum by the iscom ELISA, and by an avidity ELISA to establish the timing of infection. In addition, data on reproductive performance were compiled. During the study the percentage of seropositive female animals increased from 63% to 87%. In 1994 a large number of young animals tested seropositive although their dams were seronegative, indicating that a transmission of the parasite other than the vertical had recently occurred. Low avidity values supported this assumption. The annual abortion rate increased from a mean of 2% before the initiation of the study to 9% in 1994-1998. During the same time, as judged by the avidity data, a large proportion of the animals shifted from being recently to being chronically infected. The source of the external infection in the herd could not be identified.     

用重组蛋白 NcSAG1t作为ELISA诊断抗原进行改良绒山羊Neospora caninum的血清学诊断

N caninum；NcSAG1t；ELISA；改良绒山羊；抗体     

Adaptation of a commercial ELISA for the detection of antibodies against Neospora caninum in bovine milk

The aim of the present study was to determine whether a commercially available ELISA could be used to examine bovine milk for antibodies against Neospora caninum. In an initial titration experiment, a milk dilution of 1:2 was found optimal to obtain milk results that were linearly correlated to those obtained with corresponding sera. This dilution was then used to examine 791 milk samples from N. caninum infected herds in the commercial ELISA. Milk results of individual animals were compared with those obtained by the same ELISA for the corresponding serum samples. The linear correlation between milk and serum antibody results of individual animals was characterized by R2 = 0.702. Multiple linear regression indicated that the later the stage of lactation at which an animal was sampled, the higher the milk ELISA result was as compared to the serum ELISA result. The examination of the two-graph receiver operating characteristics revealed an optimal cut-off of 0.261 to obtain similar results in the examination of milk and serum. With this cut-off, the test had a sensitivity and specificity relative to the serum results of 90%. The milk-based commercial ELISA classified more aborting dams as positive than the serum-based ELISA with this cut-off. The milk ELISA may be a valuable tool to assess the herd status with regard to abortion caused by N. caninum.     

Diagnostic performance of PCR and ELISA on blood and milk samples and serological survey for small ruminant lentiviruses in central Spain

The diagnostic performance of an ELISA for the detection of antibodies to the small ruminant lentiviruses (SRLVs) maedi-visna virus and caprine arthritis-encephalitis virus in milk and corresponding blood samples was evaluated in 50 sheep. The agreement between ELISA results in blood and milk was 90 per cent, and the κ value was 0.79. In addition, a serological survey in the central zone of Spain was performed using milk samples from 413 animals (250 sheep and 163 goats) from 12 flocks/herds. All flocks/herds had some animals that were positive for SRLV. Among the animals, 60.0 per cent of the sheep and 8.0 per cent of the goats tested were seropositive. Each sample was also tested using a PCR technique, which increased the percentage of positive animals detected. Using a combination of ELISA and PCR gave a total of 72.2 per cent of sheep and 28.8 per cent of goats positive for SRLV.     

Seroprevalence of Toxoplasma gondii and Neospora caninum in dairy goats from Romania

Little information is available about the seroprevalence of Toxoplasma gondii and Neospora caninum infections in goats in Romania and even in Europe. During 2007-2010, 735 serum samples were collected from dairy goats located in 4 historical regions (Cri?ana, Maramure?, Transylvania and Muntenia) of Romania. Sera were analyzed for T. gondii and N. caninum antibodies (IgG type) by enzyme-linked immunosorbent assay (ELISA) using two commercial kits (Chekit Toxotest Antibody ELISA and Chekit Neospora caninum Antibody ELISA; Idexx-Bommeli, Switzerland). Three hundred and eighty-eight out of 735 (52.8%) goats presented T. gondii antibodies and 12 out of 512 (2.3%) goats had N. caninum antibodies. The high seroprevalence of T. gondii suggests that infection with this parasite is common in dairy goats in Romania, and less common the infection with N. caninum. This is the first time that infection with N. caninum in goats has been reported in Romania and the first extended study on seroepidemiology of T. gondii.     

Dynamics of anti-Neospora caninum antibodies during gestation in chronically infected dairy cows

The dynamics of antibody production against Neospora caninum during the gestation period was examined in chronically infected dairy cows. Data were obtained from 86 pregnant parous dairy cows, 21 of which had suffered abortion. The cows belonged to two herds in which a diagnosis of N. caninum infection had been previously confirmed in aborted foetuses. Pregnancy diagnosis and blood collection were performed on post-insemination Days 40, 90, 120, 150, 180, 210, and at parturition or until the time of abortion detection. Blood plasma was tested for antibodies against N. caninum using ELISA. The non-aborting cows were divided into two groups according to whether their antibody values in the second half of gestation had increased or not, while aborting cows were classified as those showing an antibody peak before abortion or those not showing a pre-abortion peak. Differences in antibody values throughout pregnancy in each group of non-aborting and aborting cows were analysed by GLM repeated measures of analysis of variance. While 32 non-aborting cows (49%) showed a significant and consistent increase in anti-Neospora antibody values during the second half of gestation, antibody values in the remaining 33 non-aborting cows were practically constant throughout gestation. An antibody peak around abortion was observed in 11 aborting cows (52%), while antibody values in the remaining 10 aborting cows were similar before and at abortion. Seroprevalence fluctuations, defined as seronegative blood samples at some point during the gestation period, were, furthermore, observed in 2 aborting and 11 non-aborting cows. Our results indicate two clearly distinguishable types of humoral immune dynamics throughout gestation: an increased or flat production of antibodies during the second half of gestation in non-aborting animals and before abortion in aborting cows. The observation that some Neospora-infected dams can exhibit negative antibody values at any time during gestation, particularly at parturition or abortion, prompts future studies designed to explore the use of new ELISA strategies at the farm level.     

Anti-Neospora caninum antibodies in milk in relation to production losses in dairy cattle

A comprehensive field study was carried out with the following objectives: (a) to assess the usefulness of individual and bulk tank milk analysis for determining Neospora caninum serostatus in individual cows and herds, and (b) to study the associations between N. caninum infection status (based on milk testing), and several productive and reproductive parameters in the animals. Antibodies were detected with a commercially available ELISA test (Bio K 192/5). Analysis of paired serum and milk samples from 1134 lactating cows on 38 farms revealed that 97.6% of the ELISA results were coincident, irrespective of whether serum or milk samples were used. Moreover, multiple linear regression analysis revealed that 86.0% of the variations in ELISA values in milk were due to variations in the serum. The measurement of antibodies in bulk tank milk was a good estimator of the herd level status of N. caninum infection, and enabled detection of infection in 94.7% herds with ≥10.0% seropositive cows and/or in all herds with >4% highly seropositive cows. The odds ratio for abortion in seropositive animals was 9.1 times higher than in seronegative animals. The infection serostatus was also a significant risk factor, as the odds ratio for abortion was even higher (12.0 times) in cows categorized as highly seropositive. ELISA values for the bulk milk from 387 randomly selected herds were negatively associated with average milk production. Moreover, milk production losses mainly occurred on farms categorized as highly positive (i.e. herds with ≥20.0% seropositive cows).     

Seroprevalence of antibodies to <Emphasis Type="Italic">Neospora caninum</Emphasis> in <Emphasis Type="Italic">Bos javanicus</Emphasis> (‘Bali cattle’) from Indonesia

A cross-sectional survey was performed to obtain first information on the presence of Neospora caninum infection in Bos javanicus (‘Bali cattle’), the predominant beef cattle in the Eastern Islands of Indonesia. Serum samples were collected from 438 Bali cattle of two age classes (<2 years, >2 years) and both genders at three slaughterhouses in the Bali island, and examined for N. caninum-specific antibodies using native NcSRS2 (p38 antigen) as an ELISA antigen. The estimated overall seroprevalence of antibodies was 5.5% (95% CI: 3.5–8.0%). The seroprevalence was not significantly associated with age class or gender of the animals. The results give first serological evidence for the presence of natural N. caninum infection in Bos javanicus and indicate its occurrence in Indonesia.