Comparison of indirect ELISA based on recombinant protein NcSRS2 and IFAT for detection of Neospora caninum antibodies in sheep (original) (raw)
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Microorganisms, 2021
Neospora caninum is an intracellular protozoan parasite responsible for numerous abortion outbreaks and neonatal abnormalities in cattle. Rapid and accurate diagnosis is critical for N. caninum control owing to the lack of vaccine or drug-based control strategies. Herein, we evaluated the performance of four frequently used antigens in the diagnosis of N. caninum infection using immunochromatographic tests (ICTs) as a rapid, affordable, and field applicable tool. These antigens included recombinant proteins of N. caninum surface antigen 1 (NcSAG1), dense granule proteins 7 (NcGRA7) and 6 (NcGRA6), in addition to native Neospora lysate antigen (NLA). Our study revealed the utility of all antigen-based ICTs for detection of specific antibodies to N. caninum. However, the NcSAG1-based ICT was the best for detection of all control N. caninum-infected mouse or cattle sera, while NcGRA7 and NcGRA6-based ICTs exhibited specific ability to detect samples from acute and sub-acute infection i...
Development of an indirect ELISA-NcSRS2 for detection of Neospora caninum antibodies in cattle
Veterinary parasitology, 2011
Neosporosis is of alarming economic concern in the cattle industry. The effectiveness of diagnostic tests for detecting specific antibodies against Neospora caninum is hampered by potential cross-reaction with other coccidia. Use of a single specific antigen might improve test specificity. An indirect enzyme-linked immunosorbent assay (ELISA) was developed using the truncated protein NcSRS2 expressed in Escherichia coli. The ELISA results were compared with those of the indirect fluorescence antibody test (IFAT). Receiver Operating Characteristic (ROC) and Tests in the Absence of a Gold Standard (TAGS) analysis revealed an assay having 96% specificity and 95% sensitivity when applied to 145 positive and 352 negative sera from two distinct cattle populations. Using OD ≤ 0.095 as the cut-off point, the assay's negative and positive predictive values ranged from 98.8% to 50.8% and from 58.8% to 99.1%, respectively, depending on neosporosis prevalence in a given area. The novel ELIS...
Iranian journal of parasitology, 2013
Neospora caninum is a protozoan parasite from phylum apicomplexa and an important agent causing abortion in cattle which produce notable economic loss all around the world. Dot-Elisa was set up performing checker board procedure and then 178 sera of cattle examined with commercial indirect ELISA and direct agglutination test (DAT) were also evaluated by dot-ELISA afterwards. Kappa statistical analysis revealed that Dot-ELISA has good agreements with ELISA as well as the DAT and also, Mc Nemar's analyzing showed that this procedure has acceptable ability to discriminate positive results. Relative sensitivity and specificity of Dot-ELISA were respectively 92.63% and 89.16% and 93.4% and 90.8% in comparison with ELISA and DAT. Since the dot-ELISA is easy, inexpensive and not needed high experience to interpret the results, it is superior to ELISA and DAT when we aim to screen the cattle on the farm and slaughterhouses or when the laboratory equipment is not available.
Clinical and Vaccine Immunology, 2005
An immunochromatographic test (ICT) with recombinant surface antigen 1 of Neospora caninum (NcSAG1) was developed for the rapid detection of antibodies to N. caninum in cattle. The ICT was used to clearly discriminate between immunofluorescent-antibody test (IFAT)-positive bovine sera and IFAT-negative bovine sera. Serum samples collected from cattle in Yanbian, China, were examined by the ICT. Of the 96 serum samples, 23 (24.0%) were positive by the ICT, and 19 (19.8%) samples were positive by a previously developed enzyme-linked immunosorbent assay (ELISA). Eighteen of 19 ELISA-positive samples were positive according to the ICT. A good agreement was found between the results of the ICT and the ELISA. The results presented here suggest that the ICT with recombinant truncated NcSAG1 fused to glutathione S-transferase is a useful and reliable method for the detection of antibodies to N. caninum in cattle.
Journal of Veterinary Medical Science, 2013
Bovine abortion caused by the Apicomplexan parasite Neospora caninum is a major economic problem in the livestock industry worldwide. Our study measured the prevalence and temporal changes in levels of antibodies specific for two N. caninum derived antigens, NcSAG1 and NcGRA7, to determine an appropriate strategy for serodiagnosis. Using an enzyme-linked immunosorbent assay (ELISA), blood samples showed that 71 cows out of 129 were positive for anti-NcSAG1 antibodies and that only nine cows were positive for anti-NcGRA7 antibodies. By longitudinal sampling, it was revealed that positive and negative antibody conversion occurred frequently for anti-NcGRA7, but that anti-NcSAG1 antibodies persisted for a long-term. These results indicate the usefulness of measuring anti-NcSAG1 antibody levels for the detection of chronically infected cows. Twelve cows showed positive seroconversion during pregnancy, nine of which showed seropositivity for anti-NcGRA7 antibody at the sixth and/or seventh month of pregnancy; serum samples were not obtained from the remaining three cows during this period. Therefore, the optimal time for detection of anti-NcGRA7 antibodies appears to be between the fifth and eighth month of pregnancy.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 2009
Neospora caninum is a parasite responsible for abortion in cows and neuromuscular disease in dogs. Serology is the most widely used technique to evaluate the prevalence of N. caninum in different host populations. A sandwich enzyme-linked immunosorbent assay (ELISA) based on the use of an anti-SRS2 monoclonal antibody was evaluated against the indirect fluorescent antibody test for 100 canine sera and against a well-characterized ELISA for 102 bovine sera. In cattle sera, the relative sensitivity and relative specificity were 100%. In dog sera, the relative specificity and relative sensitivity were 94% and 86%, respectively. The kappa value was 1 for bovine sera and 0.77 for canine sera. The seroprevalence was 3.9% in bovine sera and 21-23% in canine sera. The SRS2 sandwich ELISA was considered a valuable tool in both species.
Journal of Veterinary Diagnostic Investigation, 2011
Neospora caninum is a protozoan parasite that causes an important reproductive disease in cattle. Neospora caninum surface antigen 1 (Nc-SAG1) is an immunodominant candidate for the development of a diagnostic reagent for neosporosis. The current study describes the development and evaluation of an antigen print immunoassay (APIA) with recombinant Nc-SAG1 for the detection of specific antibodies to N. caninum in cattle. The concordance between APIA and a commercial enzyme-linked immunosorbent assay (ELISA) was evaluated with 232 serum samples from experimentally and naturally infected cattle. Sixty-one (26.7%) samples were positive for antibodies to N. caninum by ELISA and 58 (25.4%) by APIA. The new assay had a sensitivity of 85% and a specificity of 96%. These results, along with the potential of APIA to evolve into a multiple antigen detection format, suggest that this method would be a reliable diagnostic test for detection of antibodies to N. caninum in cattle.
Journal of Veterinary Diagnostic Investigation, 2014
Brief Research Reports Neospora caninum, the causative agent of neosporosis, is an apicomplexan intracellular parasite causing paresis in dogs and abortion in cattle. 2,3 Studies of the domestic life cycle of the parasite have shown that dogs are both intermediate and definitive hosts, whereas cattle are natural intermediate hosts. 2 Diagnosis of neosporosis can be achieved using histology, immunohistochemical staining, polymerase chain reaction, and serology. 4 Serological tests have the advantage that they can be applied antemortem, but suffer from not being able to discriminate between latent and acute infections. 4 Serological techniques for the specific detection of bovine and canine antibodies to N. caninum include the indirect fluorescent antibody test (IFAT), 2 immunoblotting (IB), 1 the direct agglutination test (DAT), 17 and a variety of enzymelinked immunosorbent assays (ELISAs). 5 The accepted reference method for serological diagnosis is IFAT, 6 with IFAT having been used in many species and generally considered the "gold standard" when evaluating new methods. 2-4 However, use of whole tachyzoite antigen in any serological assay may result in high background absorbance values and cross-reactivity with antibodies against related parasites such as Toxoplasma gondii. 5 Compared with the native antigens, recombinant antigens are easily produced in large quantities and can be readily standardized for diagnostic assays. In addition, their use may minimize the risk of crossreactivity with other parasite species. 15 The molecular search for diagnostic antigens for N. caninum infection has focused on the identifying immunodominant antigens that are recognized by sera from infected animals. In this sense, the dense granule proteins, NcGRA7 and NcGRA6, of N. caninum were shown to be effective candidates to diagnose N. caninum infection in cattle when used in ELISA. 9-11 In contrast to the other serological techniques (e.g., ELISA, IFAT, IB), which are laborious and time-consuming and require specialized expertise and equipment, the latex agglutination test (LAT) is a technique that is very simple to carry out, making it suitable for clinical or field applications. 18 In the present study, the performance of a LAT using recombinant NcGRA6 was evaluated for the serological detection of specific antibodies to N. caninum and compared 5480V DIXXX10.1177/1040638713515480Neospora caninum serological methodsGhalmi et al.
A study of Neospora caninum antibody seroprevalence ın dairy cows in Turkey
Journal of the Hellenic Veterinary Medical Society, 2020
Neospora caninum is a intracellular protozoan parasite and is one of the major causes of repeated abortions, foetal malformations, pre-term deliveries, stillbirth and possible loss of milk yield in livestock. The presence of specific antibodies against N. caninum in the blood serum of dairy cows is investigated in the present study. A total of 184 blood serum samples of dairy cows were examined in Bursa province in the Marmara Region. N. caninum antibodies were measured using an indirect enzyme-linked immunosorbent assay (ELISA) (The Svanovir Neospora-Ab ELISA). From the total sample, antibodies to N. caninum were detected in 62 of the 184 examined cows (33.3%) and neurological findings were seen in a calf.