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Seroprevalence of Neospora caninum Infection in Dog Population Worldwide: A Systematic Review and Meta-analysis. Acta Parasitol 2020; 65:273-290. [PMID: 31919799 DOI: 10.2478/s11686-019-00163-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 12/18/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE Neospora caninum is an obligate intracellular apicomplexan protozoan that causes neurological disorders in dogs. This systematic review and meta-analysis targeted at evaluating the worldwide seroprevalence rate of N. caninum in dogs. METHODS Five electronic databases, including PubMed, Scopus, Web of Science, Science Direct, and Google Scholar, until December 2018 were thoroughly searched for relevant English language articles. Papers were selected based on inclusion criteria. Data were analyzed in StatsDirect statistical software (version 2.7.9). RESULTS The searching process yielded a total number of 156 papers. The total prevalence (95% confidence intervals) of N. caninum infection in dog population worldwide was measured as 17.14% in data analyses (15.25-19.10). In addition, a significant association was also detected between neosporosis infection in dogs and continent, country, year, WHO regions, sample size and diagnostic method (P < 0.001). CONCLUSION Dogs are a matter of concern to public health officials as a source of N. caninum infection. Therefore, it is of paramount importance to provide comprehensive data and systematically analyze the prevalence of N. caninum infection in dogs. Accordingly, it is recommended that researchers carry out further studies to prevent and control neosporosis among dog population worldwide.
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[A comparative study of commercial ELISAs for antibody detection in the diagnostic investigation of Neospora caninum-associated abortion in dairy cattle herds in Uruguay]. Rev Argent Microbiol 2019; 52:107-114. [PMID: 31787448 DOI: 10.1016/j.ram.2019.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/30/2019] [Accepted: 06/24/2019] [Indexed: 11/23/2022] Open
Abstract
Bovine abortion causes considerable economic losses to the livestock industry worldwide and is of concern for public health and food safety, given that many abortigenic infectious agents of cattle are zoonotic. Despite its importance, the etiological diagnosis of abortion in cattle is challenging both for veterinary practitioners and laboratory technicians, partly due to the difficulty in recovering aborted fetuses under extensive field conditions for pathological and microbiological diagnostic investigation, and in the early identification of aborted dams. Neospora caninum is a cosmopolitan protozoon identified as one of the main abortigenic agents in cattle worldwide. In this study we propose a comparative seroepidemiological approach for the diagnosis of abortion by N. caninum in dairy cattle. Samples from 12 to 93 cows/heifers with and without recent history of abortion (cases and controls) in four commercial dairy farms were tested. The ratio of controls to cases tested varied from 1:1 to 4.6:1. All samples (n=230) were analyzed by three commercial ELISA kits for the detection of anti-N. caninum antibodies. In all four dairy farms, the proportion of seropositive cows and/or heifers per kit was significantly higher in the cases than in the controls (Odds Ratios=5.13 to 36, p=0.0002 to 0.0485). The agreement among the three kits varied from weak to strong (Coheńs kappa coefficients=0.58 to 0.83). We conclude that, despite the imperfect agreement between these kits, all of them allowed to arrive at similar conclusions regarding the statistical association between N. caninum seropositivity and abortion, thus representing a useful tool for the diagnostic approach at the population level under field conditions.
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Derdour SY, Hafsi F, Azzag N, Tennah S, Laamari A, China B, Ghalmi F. Prevalence of The Main Infectious Causes of Abortion in Dairy Cattle in Algeria. J Vet Res 2017; 61:337-343. [PMID: 29978092 PMCID: PMC5894425 DOI: 10.1515/jvetres-2017-0044] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/11/2017] [Indexed: 02/04/2023] Open
Abstract
Introduction Abortion in cattle is a major source of economic losses for the agriculture sector. It can be due to infectious or non-infectious factors. Among infectious factors, parasites, bacteria, viruses, and fungi can be involved. The present work investigated the prevalence of the main infectious agents of abortion in Algerian cattle. Material and Methods Altogether 278 non-aborting and 82 aborting cows were analysed. Results The prevalence ranged from 0% for Tritrichomonas foetus to 15% for Neospora caninum. Additionally, a case-control study was performed to find the association between the presence of the pathogens and the occurrence of abortion in cows. The odds ratios were significant for Neospora caninum, bovine herpes virus 4, BVD virus, Brucella abortus, Salmonella Dublin, Leptospira interrogans serovar Hardjo, and Coxiella burnetii. Conclusions The pathogens enumerated here could be major causes of abortion among Algerian cattle.
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Affiliation(s)
- Salima-Yamina Derdour
- Research Laboratory Management of Local Animal Resources, Higher National Veterinary School, El Alia, Oued Smar, 1615 Algiers, Algeria
| | - Fella Hafsi
- Research Laboratory Management of Local Animal Resources, Higher National Veterinary School, El Alia, Oued Smar, 1615 Algiers, Algeria
| | - Naouelle Azzag
- Research Laboratory Management of Local Animal Resources, Higher National Veterinary School, El Alia, Oued Smar, 1615 Algiers, Algeria
| | - Safia Tennah
- Research Laboratory Management of Local Animal Resources, Higher National Veterinary School, El Alia, Oued Smar, 1615 Algiers, Algeria
| | - Abdelouahab Laamari
- Research Laboratory Management of Local Animal Resources, Higher National Veterinary School, El Alia, Oued Smar, 1615 Algiers, Algeria
| | - Bernard China
- Scientific Institute for Public Health, 1050, Brussels, Belgium
| | - Farida Ghalmi
- Research Laboratory Management of Local Animal Resources, Higher National Veterinary School, El Alia, Oued Smar, 1615 Algiers, Algeria
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Guido S, Katzer F, Nanjiani I, Milne E, Innes EA. Serology-Based Diagnostics for the Control of Bovine Neosporosis. Trends Parasitol 2015; 32:131-143. [PMID: 26711188 DOI: 10.1016/j.pt.2015.11.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 11/30/2022]
Abstract
The protozoan Neospora caninum is a primary infectious cause of abortion in cattle that causes significant economic losses worldwide. Because effective vaccines and licensed pharmacological treatments are currently unavailable, control measures rely on biosecurity and management practice. Serological diagnosis plays a crucial role in the identification of infected animals and several tests have been developed. However, owing to the particular dynamics of the host-parasite interaction and to the characteristics of the currently used diagnostic tools, a proportion of infected cattle may not be reliably identified, and can potentially undermine efforts towards the control of bovine neosporosis. Current diagnostic methods for N. caninum infection in cattle and the advances necessary to support effective control strategies are discussed.
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Affiliation(s)
- Stefano Guido
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK; The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK.
| | - Frank Katzer
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK
| | - Ian Nanjiani
- Westpoint Veterinary Group, Dawes Farm, Bognor Road, Warnham, West Sussex, RH12 3SH, UK
| | - Elspeth Milne
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
| | - Elisabeth A Innes
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK
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Pinheiro AF, Borsuk S, Berne MEA, Pinto LDS, Andreotti R, Roos T, Roloff BC, Leite FPL. Use of ELISA based on NcSRS2 of Neospora caninumexpressed in Pichia pastoris for diagnosing neosporosis in sheep and dogs. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA 2015; 24:148-54. [DOI: 10.1590/s1984-29612015015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/11/2015] [Indexed: 11/21/2022]
Abstract
Neosporosis is a disease caused by the protozoon Neospora caninum that leads to significant economic losses in many countries. In the present study, we report on use of the recombinant protein NcSRS2 of N. caninum expressed in Pichia pastoris in an indirect immunoenzymatic assay (ELISA) for diagnosing neosporosis infection in sheep and dogs. We observed that the ELISA test yielded specificity of 94.5% and sensitivity of 100% for sheep and specificity of 93.3% and sensitivity of 100% for dogs. We observed that the sensitivity was higher than shown by the indirect fluorescent antibody test, and this was confirmed by means of Western blot. The results from this study suggest that the recombinant protein expressed in P. pastoris is a suitable antigen for use in immunodiagnosis to detect N. caninum in two important species exposed to this parasitosis.
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Roelandt S, Van der Stede Y, Czaplicki G, Van Loo H, Van Driessche E, Dewulf J, Hooyberghs J, Faes C. Serological diagnosis of bovine neosporosis: a Bayesian evaluation of two antibody ELISA tests for in vivo diagnosis in purchased and abortion cattle. Vet Rec 2015; 176:598. [DOI: 10.1136/vr.102872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2015] [Indexed: 11/04/2022]
Affiliation(s)
- S. Roelandt
- Unit Coordination of Veterinary Diagnosis & Epidemiology and Risk analysis (CDD-ERA); Operational Directorate of Surveillance and Interactions, Veterinary and Agrochemical Research Centre (CODA-CERVA); Groeselenberg, 99 Brussels B-1180 Belgium
| | - Y. Van der Stede
- Unit Coordination of Veterinary Diagnosis & Epidemiology and Risk analysis (CDD-ERA); Operational Directorate of Surveillance and Interactions, Veterinary and Agrochemical Research Centre (CODA-CERVA); Groeselenberg, 99 Brussels B-1180 Belgium
- Laboratory of Veterinary Immunology; Faculty of Veterinary Medicine; Ghent University; Merelbeke Belgium
| | - G. Czaplicki
- Unit of Porcine Production; Association Régionale de Santé & d’ Identification Animales (ARSIA); Loncin Belgium
| | - H. Van Loo
- Unit Health Care (Bovine); Dierengezondheidszorg Vlaanderen (DGZ); Torhout Belgium
| | - E. Van Driessche
- Unit Health Care (Bovine); Dierengezondheidszorg Vlaanderen (DGZ); Torhout Belgium
| | - J. Dewulf
- Veterinary Epidemiology Unit, Department of Reproduction, Obstetrics and Herd Health; Faculty of Veterinary Medicine; Ghent University; Merelbeke Belgium
| | - J. Hooyberghs
- Directorate Control and Policy, Federal Agency for Safety of the Food Chain; Brussels Belgium
| | - C. Faes
- Interuniversity Institute for Biostatistics and statistical Bioinformatics (I-BioStat), Hasselt University; Diepenbeek Belgium
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Ghalmi F, China B, Jenkins M, Azzag N, Losson B. Comparison of different serological methods to detect antibodies specific to Neospora caninum in bovine and canine sera. J Vet Diagn Invest 2014; 26:136-40. [DOI: 10.1177/1040638713515480] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Neospora caninum is an apicomplexan parasite responsible for paresis in dogs and abortion in cattle worldwide. Dogs serve as a definitive host, while cattle serve as intermediate host. Many different methods have been developed to detect specific antibodies present in cattle and dog serum. In the present study, the dense granule protein NcGRA6 was incorporated in a latex beads agglutination test (LAT), and compared to other serological methods, including enzyme-linked immunosorbent assay, the direct agglutination test, the immunoblot, and the indirect fluorescent antibody test (IFAT). Using the IFAT as the reference method, 100 sera isolated from Algerian cattle and 100 sera isolated from Algerian dogs, both possibly infected with N. caninum, were used to evaluate the LAT. The sensitivity, specificity, and kappa index were calculated for each host species and assay. For dog sera, the sensitivity and the specificity of the LAT was 76% and 100%, respectively. The McNemar test showed that the LAT was not significantly different from IFAT ( P > 0.05). For cattle sera, the sensitivity and the specificity of the LAT were 60% and 100%, respectively. The McNemar test indicated that the LAT was significantly different from IFAT ( P < 0.01) and that the LAT was only positive for cattle sera with titers of 1:800 or greater, indicating that LAT can be used for cattle in a clinical context. As well, the LAT has the advantage of being easy and rapid to perform compared to the other assays.
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Affiliation(s)
- Farida Ghalmi
- High National Veterinary School of Algiers, Algiers, Algeria (Ghalmi, Azzag)
- Scientific Institute of Public Health, Brussels, Belgium (China)
- Faculty of Veterinary Medicine, University of Liege, Liege, Belgium (Ghalmi, Losson)
- Beltsville Agricultural Research Center, U.S. Department of Agriculture, Beltsville, MD (Jenkins)
| | - Bernard China
- High National Veterinary School of Algiers, Algiers, Algeria (Ghalmi, Azzag)
- Scientific Institute of Public Health, Brussels, Belgium (China)
- Faculty of Veterinary Medicine, University of Liege, Liege, Belgium (Ghalmi, Losson)
- Beltsville Agricultural Research Center, U.S. Department of Agriculture, Beltsville, MD (Jenkins)
| | - Mark Jenkins
- High National Veterinary School of Algiers, Algiers, Algeria (Ghalmi, Azzag)
- Scientific Institute of Public Health, Brussels, Belgium (China)
- Faculty of Veterinary Medicine, University of Liege, Liege, Belgium (Ghalmi, Losson)
- Beltsville Agricultural Research Center, U.S. Department of Agriculture, Beltsville, MD (Jenkins)
| | - Naouelle Azzag
- High National Veterinary School of Algiers, Algiers, Algeria (Ghalmi, Azzag)
- Scientific Institute of Public Health, Brussels, Belgium (China)
- Faculty of Veterinary Medicine, University of Liege, Liege, Belgium (Ghalmi, Losson)
- Beltsville Agricultural Research Center, U.S. Department of Agriculture, Beltsville, MD (Jenkins)
| | - Bertand Losson
- High National Veterinary School of Algiers, Algiers, Algeria (Ghalmi, Azzag)
- Scientific Institute of Public Health, Brussels, Belgium (China)
- Faculty of Veterinary Medicine, University of Liege, Liege, Belgium (Ghalmi, Losson)
- Beltsville Agricultural Research Center, U.S. Department of Agriculture, Beltsville, MD (Jenkins)
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Pinheiro AF, Borsuk S, Berne MEA, Pinto LDS, Andreotti R, Roos T, Rollof BC, Leite FPL. Expression of Neospora caninum NcSRS2 surface protein in Pichia pastoris and its application for serodiagnosis of Neospora infection. Pathog Glob Health 2013; 107:116-21. [PMID: 23683365 DOI: 10.1179/2047773213y.0000000082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Neospora caninum is considerd a major cause of abortion in cattle worldwide. The antigenic domain of NcSRS2 in N. caninum is an important surface antigen present in the membrane of this parasite. In the present study, the Pichia pastoris expression system proved to be a useful tool for the production of recombinant protein. The truncated NcSRS2 gene (by removal of the N-terminal hydrophobic sequence), was cloned in the vector pPICZalphaB, and integrated on the genome of the methylotrophic yeast P. pastoris. Subsequently, the NcSRS2 protein was expressed, purified, and characterized using naturally infected cattle sera and Mab 6xhistag. The recombinant protein NcSRS2 was present in the supernatant of the culture, where later it was concentrated and purified using ammonium sulfate (∼100 mg/ml). An indirect immunoenzymatic assay (ELISA) was performed using cattle sera from endemic N. caninum area.
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Alvarez-García G, García-Culebras A, Gutiérrez-Expósito D, Navarro-Lozano V, Pastor-Fernández I, Ortega-Mora LM. Serological diagnosis of bovine neosporosis: A comparative study of commercially available ELISA tests. Vet Parasitol 2013; 198:85-95. [DOI: 10.1016/j.vetpar.2013.07.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 07/17/2013] [Accepted: 07/22/2013] [Indexed: 10/26/2022]
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He P, Li J, Gong P, Liu C, Zhang G, Yang J, Tuo W, Yang B, Zhang X. Neospora caninum surface antigen (p40) is a potential diagnostic marker for cattle neosporosis. Parasitol Res 2013; 112:2117-20. [PMID: 23435920 DOI: 10.1007/s00436-013-3309-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/18/2013] [Indexed: 10/27/2022]
Abstract
Neospora caninum is an intracellular protozoan that infects domestic and wild canids as well as many warm-blooded animals as shown by the isolation of viable parasites. The effectiveness of diagnostic tests for detecting specific antibodies against N. caninum is hampered by potential cross-reaction with other Coccidia. So, there is currently an urgent need for a sensitive and specific diagnostic assay for detecting N. caninum in animals. The N. caninum 40-kD surface antigen (p40), similar to NcSAG1 and NcSRS2, was shown to belong to surface antigen super family and thus represents an excellent marker for the diagnosis of neosporosis. In order to test the hypothesis, recombinant Ncp40 (rNcp40) was expressed in Escherichia coli, and an indirect ELISA test was developed using recombinant NCp40 antigen for N. caninum serodiagnosis. The antigen used in this study did not have cross-reactivity with anti-Toxoplasma gondii serum. Anti-p40 antibodies were detected by ELISA in the sera of Yellow cattle and were compared with (IFAT). Optimal sensitivity and specificity (98.2 and 98.6 %) were identified by IFAT. Additionally, 37 positive sera of T. gondii were detected and there was no significant difference with the negative serum of N. caninum. The rNcp40 ELISA developed here provides a specific and sensitive assay for detecting neosporosis in cattle.
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Affiliation(s)
- Pengfei He
- College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xian Road, Changchun, 130062, People's Republic of China
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Vangeel I, Méroc E, Roelandt S, Welby S, Riocreux F, Stede YVD, Driessche EV, Schoubroeck LV, Czaplicki G, Quinet C, Hooyberghs J, Houdart P, Stede YVD. Seroprevalence of Neospora caninum, paratuberculosis and Q fever in cattle in Belgium in 2009-2010. Vet Rec 2012; 171:477. [PMID: 22952130 DOI: 10.1136/vr.101016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- I Vangeel
- Veterinary and Agrochemical Research Centre, Coordination of Veterinary Diagnostics, Epidemiology and Risk Assessment (CVD-ERA), Groeselenberg 99, Brussels, Belgium.
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Ghalmi F, China B, Ghalmi A, Hammitouche D, Losson B. Study of the risk factors associated with Neospora caninum seroprevalence in Algerian cattle populations. Res Vet Sci 2012; 93:655-61. [PMID: 22244708 DOI: 10.1016/j.rvsc.2011.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 11/19/2011] [Accepted: 12/12/2011] [Indexed: 11/26/2022]
Abstract
Bovine abortions due to Neospora caninum infection were reported worldwide. The situation in Algeria was unknown. For the evaluation of the prevalence of N. caninum and its associated risk factors, 799 cattle belonging to 87 farms of the north and northeast of Algeria were analyzed. The cattle were divided into imported cattle, local cattle and improved cattle corresponding to breeding between imported and local cattle. Sera were examined for the presence of N. caninum antibodies by indirect fluorescence antibody test. The overall seroprevalence for the 87 farms was 52.87% (41.28-62.71%). The overall animal seroprevalence was 19.64% (16.82-22.45%). The seroprevalence of N. caninum in local cattle (34.28%) was significantly higher (p<0.05) than in modern (16.04%) and improved (18.64%) cattle. The risk factors analysis indicated that cattle population, geographical location, dog presence, season, global farm hygiene or the presence of abortion were significantly associated with seroprevalence.
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Affiliation(s)
- Farida Ghalmi
- Ecole Nationale Supérieure Vétérinaire d'Alger, Algiers, Algeria.
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Ghalmi F, China B, Kaidi R, Losson B. Neospora caninum Is Associated With Abortion In Algerian Cattle. J Parasitol 2011; 97:1121-4. [DOI: 10.1645/ge-2861.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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González-Warleta M, Castro-Hermida JA, Carro-Corral C, Mezo M. Anti-Neospora caninum antibodies in milk in relation to production losses in dairy cattle. Prev Vet Med 2011; 101:58-64. [DOI: 10.1016/j.prevetmed.2011.04.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 04/27/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
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Borsuk S, Andreotti R, Leite FPL, da Silva Pinto L, Simionatto S, Hartleben CP, Goetze M, Oshiro LM, Matos MDFC, Berne MEA. Development of an indirect ELISA-NcSRS2 for detection of Neospora caninum antibodies in cattle. Vet Parasitol 2011; 177:33-8. [DOI: 10.1016/j.vetpar.2010.11.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 11/11/2010] [Accepted: 11/15/2010] [Indexed: 11/24/2022]
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Characterisation of NcGRA7 and NcSAG4 proteins: Immunolocalisation and their role in the host cell invasion by Neospora caninum tachyzoites. Acta Parasitol 2010. [DOI: 10.2478/s11686-010-0056-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AbstractNeospora caninum negatively impacts bovine reproductive performance around the world. Addressing this problem requires a greater understanding of the parasite’s molecular biology. In this study, monoclonal antibodies against recombinant proteins were successfully developed and employed to characterise two different proteins of N. caninum: the acute phase-associated NcGRA7 and the chronic phase-associated NcSAG4. Immunofluorescence with the anti-rNcGRA7 monoclonal antibody suggested that NcGRA7 trafficks from tachyzoite dense granules to the matrix of the parasitophorous vacuole and parasite’s surroundings. Furthermore, NcGRA7 is also expressed in the bradyzoite stage and localised on the matrix of bradyzoite-positive vacuoles. NcGRA7 appears to be partially involved in the tachyzoite-invasion mechanisms, as an anti-rNcGRA7 monoclonal antibody partially inhibited in vitro tachyzoite-invasion. A monoclonal antibody specific for NcSAG4 confirmed this protein’s bradyzoitespecific expression both by western blot and immunofluorescence. However, some bradyzoite-positive vacuoles only weakly expressed NcSAG4, if it was expressed at all. The specificity of the anti-rNcSAG4 monoclonal antibody was confirmed by the recognition of the NcSAG4 in the membrane surface of Nc-1SAG4c transgenic tachyzoites, which constitutively expresses NcSAG4. Blocking NcSAG4 of Nc-1SAG4c tachyzoites with the monoclonal antibody did not affect host cell invasion. However, its implication on the host cell adhesion or host immune evasion should not be discarded.
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Ghalmi F, China B, Kaidi R, Losson B. First epidemiological study on exposure to Neospora caninum in different canine populations in the Algiers District (Algeria). Parasitol Int 2009; 58:444-50. [PMID: 19723590 DOI: 10.1016/j.parint.2009.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/21/2009] [Accepted: 08/24/2009] [Indexed: 11/15/2022]
Abstract
Neospora caninum is an important cause of abortion in cattle worldwide. Dogs act as final hosts shedding oocysts in the environment. They can also harbour the extraintestinal stage of the parasite and this may be associated with a fairly rare neuromuscular condition. The sera of 781 dogs from the Algiers District were screened by IFAT for the presence of anti-N. caninum antibodies. These dogs were distributed into four populations: local stray dogs, police dogs, dogs from breeding kennels and farm dogs. The overall seroprevalence was 21.90%. Significant differences were observed between the different populations, the highest prevalence being observed in farm (44.44%) and stray dogs (22.55%). Additionally, the highest titres were observed in farm dogs. Among studied epidemiological parameters, breed, dog origin, season and vaccination status were significantly associated with IFAT results. Additionally, a recently described real time PCR was used on the blood of 100 pound dogs and the results were compared with the serological data. A higher proportion of dogs was found to be positive by PCR when compared to the IFAT results. There was only a fairly low agreement between PCR and IFAT results which suggests that these techniques measured different aspects of the host-parasite relationship. This study indicates that the level of exposure of the canine population of Algiers area to N. caninum is very high. This would indicate a potentially high risk for N. caninum induced abortion in cattle in this region and in Algeria.
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Affiliation(s)
- F Ghalmi
- University of Liege, Faculty of Veterinary Medicine, Department of Infectious Diseases, Liège, Belgium
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