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García-Díez J, Saraiva S, Moura D, Grispoldi L, Cenci-Goga BT, Saraiva C. The Importance of the Slaughterhouse in Surveilling Animal and Public Health: A Systematic Review. Vet Sci 2023; 10:167. [PMID: 36851472 PMCID: PMC9959654 DOI: 10.3390/vetsci10020167] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/14/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
From the point of public health, the objective of the slaughterhouse is to guarantee the safety of meat in which meat inspection represent an essential tool to control animal diseases and guarantee the public health. The slaughterhouse can be used as surveillance center for livestock diseases. However, other aspects related with animal and human health, such as epidemiology and disease control in primary production, control of animal welfare on the farm, surveillance of zoonotic agents responsible for food poisoning, as well as surveillance and control of antimicrobial resistance, can be monitored. These controls should not be seen as a last defensive barrier but rather as a complement to the controls carried out on the farm. Regarding the control of diseases in livestock, scientific research is scarce and outdated, not taking advantage of the potential for disease control. Animal welfare in primary production and during transport can be monitored throughout ante-mortem and post-mortem inspection at the slaughterhouse, providing valuable individual data on animal welfare. Surveillance and research regarding antimicrobial resistance (AMR) at slaughterhouses is scarce, mainly in cattle, sheep, and goats. However, most of the zoonotic pathogens are sensitive to the antibiotics studied. Moreover, the prevalence at the slaughterhouse of zoonotic and foodborne agents seems to be low, but a lack of harmonization in terms of control and communication may lead to underestimate its real prevalence.
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Affiliation(s)
- Juan García-Díez
- Veterinary and Animal Research Centre (CECAV), University of Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Portugal
| | - Sónia Saraiva
- Veterinary and Animal Research Centre (CECAV), University of Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Portugal
| | - Dina Moura
- Divisão de Intervenção de Alimentação e Veterinária de Vila Real e Douro Sul, Direção de Serviços de Alimentação e Veterinária da Região Norte, Direção Geral de Alimentação e Veterinária, Lugar de Codessais, 5000-567 Vila Real, Portugal
| | - Luca Grispoldi
- Dipartimento di Medicina Veterinaria, Università degli Studi di Perugia, 06126 Perugia, Italy
| | - Beniamino Terzo Cenci-Goga
- Dipartimento di Medicina Veterinaria, Università degli Studi di Perugia, 06126 Perugia, Italy
- Faculty of Veterinary Science, Department of Paraclinical Sciences, University of Pretoria, Onderstepoort 0110, South Africa
| | - Cristina Saraiva
- Veterinary and Animal Research Centre (CECAV), University of Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Portugal
- Faculty of Veterinary Science, Department of Paraclinical Sciences, University of Pretoria, Onderstepoort 0110, South Africa
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English ED, Adomako-Ankomah Y, Boyle JP. Secreted effectors in Toxoplasma gondii and related species: determinants of host range and pathogenesis? Parasite Immunol 2015; 37:127-40. [PMID: 25655311 PMCID: PMC4359005 DOI: 10.1111/pim.12166] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 11/26/2014] [Indexed: 12/20/2022]
Abstract
Recent years have witnessed the discovery of a number of secreted proteins in Toxoplasma gondii that play important roles in host-pathogen interactions and parasite virulence, particularly in the mouse model. However, the role that these proteins play in driving the unique features of T. gondii compared to some of its nearest apicomplexan relatives (Hammondia hammondi and Neospora caninum) is unknown. These unique features include distinct dissemination characteristics in vivo and a vast host range. In this review we comprehensively survey what is known about disease outcome, the host response and host range for T. gondii, H. hammondi, and N. caninum. We then review what is presently known about recently identified secreted virulence effectors in these three genetically related, but phenotypically distinct, species. Finally we exploit the existence of genome sequences for these three organisms and discuss what is known about the presence, and functionality, of key T. gondii effectors in these three species.
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Affiliation(s)
- E D English
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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3
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Bartley PM, Wright SE, Zimmer IA, Roy S, Kitchener AC, Meredith A, Innes EA, Katzer F. Detection of Neospora caninum in wild carnivorans in Great Britain. Vet Parasitol 2012; 192:279-83. [PMID: 23102760 DOI: 10.1016/j.vetpar.2012.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/27/2012] [Accepted: 10/03/2012] [Indexed: 11/29/2022]
Abstract
Samples of brain and other tissues were collected from 99 ferrets (Mustela furo), 83 red foxes (Vulpes vulpes), 70 European polecats (Mustela putorius), 65 American mink (Neovison vison), 64 Eurasian badgers (Meles meles) and 9 stoats (Mustela erminea), from around Great Britain. DNA was extracted from approximately 1g of tissue and tested by specific nested ITS1 PCR for Neospora caninum. The results from the PCR demonstrated that Neospora specific DNA was detected in all species of wild carnivorans with the exception of the stoats (0/9). Neospora DNA positive samples were detected in: polecats 18.6% (13/70), badgers 10.9% (7/64), ferrets 10.1% (10/99), foxes 4.8% (4/83) and mink 4.6% (3/65). In the badgers N. caninum DNA positive samples were found in brain (n=2), liver (n=2) and neck muscle (n=3). Selected positive ITS1 DNA sequences were submitted to Genbank. Sequence UKwildlife1 (accession number JX857862) was found in two badgers, whilst UKwildlife2 and UKwildlife3 (accession numbers JX857863 and JX857864 respectively) were found in ferrets, all three sequences demonstrated point mutations at a single base, while sequence UKwildlife4 (accession number JX857865) was found in all the species that tested positive and showed complete identity when compared against published reference sequences for: N. caninum (Nc Liverpool isolate, EU564166). Our data shows that almost all the wild carnivoran mammal species tested are intermediate hosts for N. caninum and are therefore capable of acting as reservoirs of infection for other species. These species could also act as useful sentinel species, demonstrating the presence of the parasite in particular geographical and environmental locations.
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Affiliation(s)
- P M Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian EH26 0PZ, Scotland, UK.
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Pinto AP, Bacha FB, Santos BS, Driemeier D, Antoniassi NA, Ribas NLDS, Lemos RA. Sheep abortion associated with Neospora caninum in Mato Grosso do Sul, Brazil. PESQUISA VETERINARIA BRASILEIRA 2012. [DOI: 10.1590/s0100-736x2012000800010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Canids are the main hosts of Neospora caninum, but cattle, (sheep, goats and horses may serve as intermediary hosts. N. caninum infection of pregnant intermediary hosts may provoke abortion and neonatal infections. This study is the first to report lamb abortion associated with N. caninum in Mato Grosso do Sul. Epidemiological data were obtained from interviews with sheep producers. For microscopic examination, fragments of different organs removed from 4 sheep fetuses, aborted and necropsied, were fixed in 10% formaldehyde, embedded in paraffin and subjected to the hematoxylin-eosin staining protocol and immunohistochemistry (IHC) to test for N. caninum and Toxoplasma gondii. The abortion outbreak studied was reported from a herd of 268 Santa Inês sheep (including 186 pregnant ewes), with 10 abortion cases in the last third of gestation. Four fetuses were examined, 3 from a same ewe. At necropsy, one fetus exhibited crackling in the lung and all its organs were reddish. Histological findings detected mononuclear cell infiltrates among myocardium fibers and around blood vessels, in addition to circular structures with basophilic points resembling protozoans. IHC tests revealed strongly positive staining for N. caninum and weakly positive for T. gondii, characterizing N. caninum infection.
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5
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Heart disease in cattle: Diagnosis, therapeutic approaches and prognosis. Vet J 2010; 184:258-63. [DOI: 10.1016/j.tvjl.2009.05.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 03/05/2009] [Accepted: 05/03/2009] [Indexed: 11/23/2022]
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Almería S, López-Gatius F, García-Ispierto I, Nogareda C, Bech-Sàbat G, Serrano B, Santolaria P, Yániz J. Effects of crossbreed pregnancies on the abortion risk of Neospora caninum-infected dairy cows. Vet Parasitol 2009; 163:323-9. [DOI: 10.1016/j.vetpar.2009.04.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 04/14/2009] [Accepted: 04/20/2009] [Indexed: 11/29/2022]
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Gibney EH, Kipar A, Rosbottom A, Guy CS, Smith RF, Hetzel U, Trees AJ, Williams DJL. The extent of parasite-associated necrosis in the placenta and foetal tissues of cattle following Neospora caninum infection in early and late gestation correlates with foetal death. Int J Parasitol 2007; 38:579-88. [PMID: 18021783 DOI: 10.1016/j.ijpara.2007.09.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 08/31/2007] [Accepted: 09/04/2007] [Indexed: 11/19/2022]
Abstract
The protozoan parasite Neospora caninum is the most frequently diagnosed abortifacient in the UK and a leading cause of abortion worldwide but the mechanisms leading to abortion are not fully understood. The distribution of parasites and the histopathological changes in the placenta and foetus were compared in 12 cows following experimental infection of cattle with N. caninum in early (n=6) and late (n=6) gestation, by PCR, immunohistology, light microscopy and transmission electron microscopy. Twelve uninfected pregnant cattle were used as controls. Infection in early gestation led to foetal death. In the placentae of cattle immediately following foetal death, N. caninum DNA was detected and there was evidence of widespread parasite dissemination. This was associated with extensive focal epithelial necrosis, serum leakage and moderate maternal interstitial mononuclear cell infiltration. In the foetuses, parasites were evident in all tissues examined and were associated with necrosis. In the placenta of cattle infected in late gestation, N. caninum DNA was detected sporadically but parasites were not evident immunohistologically. Small foci of necrosis were seen associated with mild interstitial mononuclear cell infiltration. Detection of N. caninum DNA in the foetuses was sporadic and parasites were demonstrated immunohistologically in brain and spinal cord only, with an associated mononuclear cell infiltration. This data is consistent with uncontrolled parasite spread in an immunologically immature foetus and could, via multiparenchymal necrosis of foetal tissues or the widespread necrosis and inflammation observed in the placenta, be the cause of Neospora-associated abortions.
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Affiliation(s)
- E Helen Gibney
- Veterinary Parasitology, Liverpool School of Tropical Medicine/Faculty of Veterinary Science, Pembroke Place, Liverpool L3 5QA, UK
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8
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Sadrebazzaz A, Habibi G, Haddadzadeh H, Ashrafi J. Evaluation of bovine abortion associated with Neospora caninum by different diagnostic techniques in Mashhad, Iran. Parasitol Res 2007; 100:1257-60. [PMID: 17206503 DOI: 10.1007/s00436-006-0417-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
Abstract
Twelve aborted foetuses (gestational ranged from 4-9 months) and dams from dairies cattle farms in (Mashhad) Iran were analysed to investigate the participation of Neospora caninum in abortion. Diagnosis of the infection was determined by histopathology, serology (indirect fluorescent antibody test [IFAT]) and semi-nested polymerase chain reaction (PCR). A total 33% of bovine foetuses were considered to be infected by PCR technique. Microscopic lesions consistent with N. caninum infection in foetal brains were observed in 25% of the samples, whereas 33% were positive using IFAT (with a cut-off titre of 1:20). This study confirms the importance of N. caninum as an important cause of abortion in Iran.
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Affiliation(s)
- A Sadrebazzaz
- Razi Serum and Vaccine Research Institute, P.O. Box 91735-174, Mashhad, Iran.
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9
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Dubey JP, Schares G. Diagnosis of bovine neosporosis. Vet Parasitol 2006; 140:1-34. [PMID: 16730126 DOI: 10.1016/j.vetpar.2006.03.035] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Revised: 03/17/2006] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
The protozoan parasite Neospora caninum is a major cause of abortion in cattle. The diagnosis of neosporosis-associated mortality and abortion in cattle is difficult. In the present paper we review histologic, serologic, immunohistochemical, and molecular methods for dignosis of bovine neosporosis. Although not a routine method of diagnosis, methods to isolate viable N. caninum from bovine tissues are also reviewed.
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Affiliation(s)
- J P Dubey
- Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agricultural, Beltsville, MD 20705, USA.
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10
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Dubey JP, Buxton D, Wouda W. Pathogenesis of bovine neosporosis. J Comp Pathol 2006; 134:267-89. [PMID: 16712863 DOI: 10.1016/j.jcpa.2005.11.004] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Accepted: 11/28/2005] [Indexed: 11/29/2022]
Abstract
The protozoan parasite Neospora caninum is a major pathogen of cattle and dogs, being a significant cause of abortion in cattle in many countries. It is one of the most efficiently transmitted parasites, with up to 90% of cattle infected in some herds. The pathogenesis of abortion due to Neospora is complex and only partially understood. Losses occur after a primary infection during pregnancy but more commonly as the result of recrudescence of a persistent infection during pregnancy. Parasitaemia is followed by invasion of the placenta and fetus. It is suggested that abortion occurs when primary parasite-induced placental damage jeopardises fetal survival directly or causes release of maternal prostaglandins that in turn cause luteolysis and abortion. Fetal damage may also occur due to primary tissue damage caused by the multiplication of N. caninum in the fetus or due to insufficient oxygen/nutrition, secondary to placental damage. In addition, maternal immune expulsion of the fetus may occur associated with maternal placental inflammation and the release of maternal pro-inflammatory cytokines in the placenta. Thus N. caninum is a primary pathogen capable of causing abortion either through maternal placental inflammation, maternal and fetal placental necrosis, fetal damage, or a combination of all three. The question of how N. caninum kills the fetus exposes the complex and finely balanced biological processes that have evolved to permit bovine and other mammalian pregnancies to occur. Defining these immunological mechanisms will shed light on potential methods of control of bovine neosporosis and enrich our understanding of the continuity of mammalian and protozoal survival.
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Affiliation(s)
- J P Dubey
- Animal Parasitic Diseases Laboratory, United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, BARC-East, Building 1001, 10300 Baltimore Avenue, Beltsville, MD 20705-2350, USA
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11
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McInnes LM, Irwin P, Palmer DG, Ryan UM. In vitro isolation and characterisation of the first canine Neospora caninum isolate in Australia. Vet Parasitol 2006; 137:355-63. [PMID: 16487658 DOI: 10.1016/j.vetpar.2006.01.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 01/13/2006] [Accepted: 01/15/2006] [Indexed: 11/30/2022]
Abstract
Neospora caninum was isolated and established in vitro from the skin lesion of a naturally infected dog. The identity of the parasite was evaluated by immunofluorescent antibody test (IFAT), microscopy, Western blotting and polymerase chain reaction (PCR). N. caninum DNA was detected in the whole blood, serum, skin lesion, rectal scrapings and faeces of the infected dog utilising a nested PCR targeting the Nc-5 gene of N. caninum. Antigenic and genetic characterisation of the isolate, designated WA-K9, at a number of loci including the Nc-5 gene, heat shock protein 70 (HSP-70) gene, alpha-tubulin and beta-tubulin genes revealed no variation between this isolate and two N. caninum isolates from different geographic areas. Clinical aspects of this case, which included cutaneous and neurological disease, are also discussed.
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Affiliation(s)
- L M McInnes
- Division of Health Sciences, School of Veterinary and Biomedical Science, Murdoch University, WA 6150, Australia.
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12
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Collantes-Fernández E, Rodríguez-Bertos A, Arnáiz-Seco I, Moreno B, Aduriz G, Ortega-Mora LM. Influence of the stage of pregnancy on Neospora caninum distribution, parasite loads and lesions in aborted bovine foetuses. Theriogenology 2005; 65:629-41. [PMID: 16023188 DOI: 10.1016/j.theriogenology.2005.06.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/02/2005] [Accepted: 06/06/2005] [Indexed: 10/25/2022]
Abstract
In the present work we have studied in Neospra caninum aborted bovine foetuses the influence of foetal age (first, second and third gestational periods) on parasite distribution by nested PCR, parasite loads by real-time PCR and N. caninum associated lesions. For this purpose, a total of 220 aborted foetuses were analysed and detection of N. caninum infection was accomplished by nested-PCR in brain, heart and liver, detecting the presence of the parasite in 72 (32.7%) bovine foetuses. When the different age classes were compared, parasite DNA-detectability in heart and liver was reduced over time of gestation (P < 0.05, Fisher F-test). N. caninum distribution, parasite loads and lesions were studied on 34 out of 72 N. caninum-infected foetuses selected according to the stage of pregnancy and organs recovered. A higher number of positive-PCR tissue samples were observed in the foetuses corresponding to the first and second pregnancy periods. In the last trimester, the parasite could only be detected in the brain and, sporadically, in the diaphragm, heart and lymph nodes. The parasite loads decreased during pregnancy and the foetuses from the first period had higher parasite burdens in brain, heart, kidney and lung (P < 0.05, Kruskal-Wallis H-test) than in those corresponding to the other two trimesters of pregnancy. In addition, the observed lesions were more severe in foetuses from the first and second pregnancy periods than those from the third period (P > 0.05, Kruskal-Wallis H-test). Our results confirm the influence of N. caninum foetal age on pathogenesis in natural N. caninum infections.
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Affiliation(s)
- Esther Collantes-Fernández
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
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López-Gatius F, Santolaria P, Yániz JL, Garbayo JM, Almería S. The use of beef bull semen reduced the risk of abortion in Neospora-seropositive dairy cows. ACTA ACUST UNITED AC 2005; 52:88-92. [PMID: 15752268 DOI: 10.1111/j.1439-0450.2004.00818.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is an evidence that the epidemiology of neosporosis differs in dairy and beef cattle, such that beef cattle carry a lower risk of abortion. The aim of the present study was to establish whether artificial insemination using semen from beef bulls could reduce the risk of abortion in dairy cows seropositive for the Neospora caninum parasite. Our study was based on yearly serological screening for neosporosis and on the confirmation of Neospora infection in aborted fetuses in two high-producing dairy herds with a mean 28% seroprevalence of N. caninum antibodies. The study population comprised of 273 pregnancies in seropositive animals: 156 pregnancies monitored after insemination using Holstein-Friesian semen and 117 after insemination using beef bull semen. Abortion rates for these animals were 28.2% (77 of 273), 34.6% (54 of 156) and 19.7% (23 of 117). Logistic regression analysis indicated no significant effects of lactation number and previous abortion on the abortion rate. Based on the odds ratio, a 1-unit increase in the Neospora antibody titre yielded a 1.01-fold increase in the abortion rate. The likelihood of abortion was two times higher for cows in one of the two herds and 2.8 times lower (one of 0.36) for pregnant cows inseminated with beef bull semen rather than Holstein-Friesian semen. Our results indicate that the use of beef bull semen can reduce the risk of abortion in dairy cows, and suggest that annual screening for neosporosis, specifically the antibody titre to the protozoan, could be an useful predictor of abortion risk in reproductive health programmes.
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Affiliation(s)
- F López-Gatius
- Department of Animal Production, University of Lleida, Escuela Técnica Superior de Ingeniería Agraria, Avda, Rovira Roure 177, 25198 Lleida, Spain.
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López-Gatius F, Pabón M, Almería S. Neospora caninum infection does not affect early pregnancy in dairy cattle. Theriogenology 2004; 62:606-13. [PMID: 15226015 DOI: 10.1016/j.theriogenology.2003.11.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2003] [Revised: 11/08/2003] [Accepted: 11/09/2003] [Indexed: 10/26/2022]
Abstract
This study was designed to evaluate the relationship between Neospora caninum infection prior to pregnancy, as determined through maternal serology, and the subsequent occurrence of abortion in dairy cattle. Special emphasis was placed on pregnancy losses in the first trimester of pregnancy. Neospora caninum antibodies were analyzed by commercial ELISA in 2773 pregnant animals (2022 parous cows and 751 heifers) from six herds. The mean seroprevalence of antibodies to N. caninum in the herds was 15.1% (n = 419). From gestation Day 34 to the 90th day of pregnancy, there were 183 abortions (6.6% of all pregnancies) (23 in Neospora positive animals). After 90 days of pregnancy, the number of abortions was 146 (5.3%); 126 occurring during the second and 20 during the third trimester of pregnancy (105 in Neospora positive animals). Multiple logistic regression analyses were performed on data from each animal using abortion before or after 90 days of pregnancy as the dependent variable, and Neospora positivity, herd, pregnancy season, and parity (parous or nonparous) as independent factors. No significant effects of Neospora positivity and herd were found on the abortion rate before 90 days of pregnancy. Based on the odds ratio, the abortion rate was 4 times higher (P < 0.0001) in animals that became pregnant in the warm than in the cool period, and 3.7 times higher (P < 0.0001) in parous than in nonparous animals. Neospora positivity was the only variable included in the logistic regression model for abortions occurring after 90 days of pregnancy. Seropositivity in an animal increased the probability of abortion by an odds ratio of 18.9 (P < 0.0001; 95% confidence interval 12.9-27.8). Season, parity, and herd showed no effect. The results of the present study suggest that chronic N. caninum infection prior to pregnancy appears not to affect the early fetal period, but does have a significant abortive effect after 90 days of gestation.
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Affiliation(s)
- F López-Gatius
- Department of Animal Production, University of Lleida, Lleida, Spain.
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15
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Locatelli-Dittrich R, Richartz RRTB, Joineau MEG, Pinckney RD, de Sousa RS, Leite LC, Thomaz-Soccol V. Isolation of Neospora caninum from a blind calf in Paraná, southern Brazil. Vet Rec 2003; 153:366-7. [PMID: 14533770 DOI: 10.1136/vr.153.12.366] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- R Locatelli-Dittrich
- Departamento de Medicina Veterinária, Universidade Federal do Parana, Rua dos Funcionários, 1540, CEP 80035 - 050, Curitiba, Paraná, Brazil
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Maley SW, Buxton D, Rae AG, Wright SE, Schock A, Bartley PM, Esteban-Redondo I, Swales C, Hamilton CM, Sales J, Innes EA. The pathogenesis of neosporosis in pregnant cattle: inoculation at mid-gestation. J Comp Pathol 2003; 129:186-95. [PMID: 12921725 DOI: 10.1016/s0021-9975(03)00032-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To investigate the pathogenesis of bovine neosporosis, 14 pregnant cattle were each inoculated subcutaneously with either 10(7) or 5 x 10(8) Neospora caninum (strain NC1) tachyzoites at 140 days' gestation. Serial necropsies were then carried out over an 8-week period. In the placenta, Neospora DNA and histopathological changes were observed in samples taken 14 days post-inoculation (dpi), with focal necrosis of maternal caruncular septa and fetal placental villi, serum leakage, and a maternal and fetal inflammatory response. At subsequent samplings, pathological changes in the placenta showed signs of resolution. No parasitaemia was detected in the dams in the two weeks following inoculation. In the fetus, Neospora DNA was detected at 14 dpi, and histopathological changes in the fetal central nervous system at 28 and 42 dpi consisted of small foci of necrosis and inflammation. Resolution of placental lesions during the experiment indicated that the disease was being controlled, and fetal infection, although established, did not appear to be progressing to a fatal outcome. The two doses of tachyzoites produced similar results, but the higher dose elicited earlier and more extensive lesions in the placenta and fetus. Control animals remained negative for all parameters recorded. It is concluded that in bovine neosporosis the placenta plays a central role in the pathogenesis and epidemiology of the infection, and that while primary tissue destruction by the parasite may endanger the fetus, the maternal and fetal inflammatory responses may also be damaging.
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Affiliation(s)
- S W Maley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, EH26 0PZ, UK
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Romero JJ, Frankena K. The effect of the dam-calf relationship on serostatus to Neospora caninum on 20 Costa Rican dairy farms. Vet Parasitol 2003; 114:159-71. [PMID: 12788252 DOI: 10.1016/s0304-4017(03)00135-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An epidemiological study was conducted on 20 dairy herds previously diagnosed as seropositive for Neospora caninum. The number of females per farm varies from 41 to 296. All females present on the farms were bled once in the period of July and August 2000. A total of 3002 females were bled. An indirect ELISA was used to determine the serostatus of the animals. The analysis of the data was performed in four steps: (1) descriptive statistics about the serological status and general characteristics of the cattle; (2) calculation of vertical and horizontal transmission; (3) an univariate analysis and, (4) a multivariate logistic regression analysis with herd as random effect. The within-herd seroprevalence varied between 25.0% (34/136) and 70.5% (203/288). Seven hundred and forty-seven dam-daughter pairs were available, involving daughters of any age. Daughters in the specific age-class of 2- and 3-years old had a higher seroprevalence (P<0.01) compared with younger and older age-classes. The risk of being seropositive when being born to a mother that tested seropositive (prevalence ratio (PR)) was 2.8-fold increased which coincides with a 5.3-fold increased odds. The probability of horizontal infection amounts to 0.22. The probability of a seropositive offspring due to vertical transmission was 0.64 (attributable fraction among exposed (AFexp)). The multivariate logistic regression showed a significant 6.0-fold increased odds for being seropositive when born from a seropositive mother. Also the within-herd seroprevalence level was significantly associated with the serostatus of the daughters. In the specific conditions of the dairy herds involved in this study, the serostatus of the cows should be not used as a predictor of the serostatus of daughters due to the increased probability of horizontal transmission.
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Affiliation(s)
- J J Romero
- Programa de Investigación en Medicina Poblacional, Escuela de Medicina Veterinaria, Universidad Nacional, P.O. Box 304-3000, Heredia, Costa Rica.
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18
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Pereira-Bueno J, Quintanilla-Gozalo A, Pérez-Pérez V, Espi-Felgueroso A, Alvarez-García G, Collantes-Fernández E, Ortega-Mora LM. Evaluation by different diagnostic techniques of bovine abortion associated with Neospora caninum in Spain. Vet Parasitol 2003; 111:143-52. [PMID: 12531290 DOI: 10.1016/s0304-4017(02)00361-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eighty foetuses from some of the main cattle-producing regions in Spain were analysed to investigate the participation of Neospora caninum in cases of bovine abortion. Diagnosis of the infection was determined by histopathological analysis complemented with immunohistochemistry, serology (IFAT and ELISA) and PCR tests. A total of 38.8% of the bovine foetuses analysed were considered to be infected by at least one of the diagnostic techniques used. Microscopic lesions consistent with Neospora infection in brain were identified in 31.3% of the samples, whereas only 10.7 and 15.3% were positive using serological and PCR analysis, respectively. Perfect agreement was shown between IFAT and ELISA, although there was little agreement among results of the other diagnostic techniques. Gestational age of aborted foetuses checked ranged from <3 to 9 months, with a mean of 5.9 months, and no difference in age was found between infected and non-infected foetuses (P>0.05). This study confirms the importance of N. caninum as a cause of abortion in Spain and underlines the need to use different diagnostic techniques to increase the chance to detect the infection in aborted foetuses.
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Affiliation(s)
- J Pereira-Bueno
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, 24007 León, Spain
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19
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Abstract
Since its first description in dogs in 1984, the protozoan parasite Neospora caninum has been found to infect a wide range of animals, worldwide. In cattle, N. caninum has particular significance as a cause of abortion in which persistence of infection in the mother, recrudescence of the parasite during pregnancy, and the vulnerability of the placenta and foetus to invasion are important features. This article discusses how Neospora invades cells, how it infects and causes disease in several animal species, and particularly how it has evolved a special niche in cattle and dogs that ensures its survival.
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Affiliation(s)
- David Buxton
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, UK.
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20
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De Meerschman F, Speybroeck N, Berkvens D, Rettignera C, Focant C, Leclipteux T, Cassart D, Losson B. Fetal infection with Neospora caninum in dairy and beef cattle in Belgium. Theriogenology 2002; 58:933-45. [PMID: 12212893 DOI: 10.1016/s0093-691x(02)00934-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neospora caninum is a protozoan parasite, which causes fetal and neonatal mortality in livestock and companion animals. In 224 abortions in Belgian cattle, different diagnostic methods were used to demonstrate infection, and the presence of N. caninum. An indirect fluorescent antibody test (IFAT) was used to analyze fetal and maternal sera and immunohistochemistry (IHC) was performed when lesions consistent with neosporosis were observed in the brain, heart or liver. Twenty dairy cattle sera out of 70 (29%) and 13 beef cattle sera out of 93 (14%) were positive by IFAT. A positive titer to N. caninum was found in seven and three fetuses born to beef and dairy cows, respectively. Lesions consistent with N. caninum infection were observed in 17 fetuses. Of nine positive beef fetuses, five were confirmed by IHC while, all but one dairy fetus were confirmed using the same technique. Age had no influence on the serological status of the mother (P = 0.486) whereas husbandry system had a borderline influence (P = 0.082). However, a strong association (P = 0.004) between the level of antibodies in the dam and the occurrence of lesions in the fetus was observed and lesions were more prominent in dairy than in beef fetuses. Additionally, the distribution of intra-cerebral lesions was more extensive in dairy than in beef fetuses (P < 0.0001). Age and serological status of the fetus were found to influence the occurrence of lesions in beef fetuses (both P < 0.001) but no such significant relationships could be demonstrated in dairy fetuses. The study indicated that N. caninum must be considered as an important cause of bovine abortion in Belgium.
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Affiliation(s)
- F De Meerschman
- Laboratory of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, Liège, Belgium.
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21
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Moore DP, Campero CM, Odeón AC, Posso MA, Cano D, Leunda MR, Basso W, Venturini MC, Späth E. Seroepidemiology of beef and dairy herds and fetal study of Neospora caninum in Argentina. Vet Parasitol 2002; 107:303-16. [PMID: 12163242 DOI: 10.1016/s0304-4017(02)00129-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of the present work was to study the epidemiology of Neospora caninum in beef and dairy herds in the Humid Pampas of Argentina. The seroprevalence of N. caninum was evaluated in 2414 serum samples of cows from beef and dairy farms. An indirect fluorescent antibody test (IFAT) was used to determine specific antibodies. The sera was screened at a dilution >or=1:200 and >or=1:600 in cows with reproductive disease antecedents and without them, respectively. Cows without history of reproductive diseases from nine beef and fifteen dairy farms were grouped according to the percentage (> or <or= to 50%) of seropositive dogs. Additionally, the seroprevalence in beef and dairy cattle cohabiting in the same farm with these dogs was compared. Microscopic studies were performed in 188 aborted fetuses and/or their placentas. Formalin-fixed fetal tissues with microscopic lesions compatible with N. caninum were processed by immunohistochemistry (IHC). The seroprevalence in cows without reproductive diseases was 4.7% (19/400) for beef cattle and 16.6% (174/1048) for dairy cattle. The seroprevalence of N. caninum in dairy cattle was higher (P<0.05) in farms grouped according to the percentage (> or <or= to 50%) of seropositive dogs. The analysis of 966 serum samples from aborted cows, demonstrated positive 18.9% (41/216) and 43.1% (323/750) from beef and dairy herds, respectively. Microscopic lesions compatible with N. caninum were observed in 43 of 188 (22.8%) fetuses and/or placentas evaluated. The protozoan was identified in 29 of 43 (67.4%) aborted specimens, being the largest number of positive results in dairy fetuses. The results obtained demonstrate a high association between neosporosis and dairy herds, however, our data also reveals that N. caninum is an important risk factor for reproductive losses in the extensively farmed beef cattle in the Humid Pampas of Argentina.
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Affiliation(s)
- Dadín Prando Moore
- Consejo Nacional de Investigaciones Cienti;ficas y Técnicas (CONICET), Buenos Aires, Argentina
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22
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Guy CS, Kelly DF, McGarry JW, Guy F, Björkman C, Smith RF, Trees AJ. Neospora caninum in persistently infected, pregnant cows: spontaneous transplacental infection is associated with an acute increase in maternal antibody. Vet Rec 2001; 149:443-9. [PMID: 11688746 DOI: 10.1136/vr.149.15.443] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Nine cows which were naturally and persistently infected with Neospora caninum were housed and observed intensively throughout pregnancy. No recrudescence of a latent infection was detected by PCR tests on maternal blood but fetal infection, implying a recrudescence of maternal parasitosis, was associated with a marked increase in maternal antibody. The increase occurred in the second half of pregnancy in five cows which infected their calves, and before mid-pregnancy in one cow which aborted. There was no change in the avidity of the antibody, which remained high and characteristic of long-term infection. In three infected cows that gave birth to uninfected calves there was no marked increase in maternal antibody. Antigen-specific interferon gamma responses of peripheral blood mononuclear cells were observed in all the infected cattle but they did not vary significantly either during pregnancy, or whether the cows did or did not infect their calves, although the responses were consistently higher in the latter. There was no change in the plasma concentrations of cortisol or acute phase proteins associated with the recrudescence of the parasite. Three uninfected cows housed with the infected cows remained uninfected throughout the experiment. No immunosuppressive event was detected which might have provoked parasite recrudescence but the acute antibody rise associated with transplacental infection provides a valuable, non-invasive marker for further studies to investigate the cause and consequences of parasite recrudescence in N caninum infection in cattle.
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Affiliation(s)
- C S Guy
- Veterinary Parasitology, Liverpool School of Tropical Medicine
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23
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Davison HC, Guy CS, McGarry JW, Guy F, Williams DJ, Kelly DF, Trees AJ. Experimental studies on the transmission of Neospora caninum between cattle. Res Vet Sci 2001; 70:163-8. [PMID: 11356096 DOI: 10.1053/rvsc.2001.0457] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Three studies were conducted to investigate the transmission of Neospora caninum between cattle by the oral route. In the first study, six calves were dosed with 10(7)N caninum tachyzoites (NC LivB1) in colostrum and/or milk replacer on four occasions. In the second study, two calves and two cows were fed placental tissues from N caninum -infected cows, and, in the third study, seven uninfected calves were fostered onto N caninum -infected dams. In the first study, all six calves developed antibody responses and five calves developed antigen-specific lymphoproliferation responses, including two calves initially challenged at 1 week of age. No evidence of N caninum infection was found in the brain or heart of these calves by histology or polymerase chain reaction (PCR). In the second and third studies, there was no evidence of N caninum infection in any of the calves and cows. The results confirm that calves up to 1 week of age can be experimentally infected via the oral route, but suggest that this is not an important natural route of transmission for N caninum between cattle.
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Affiliation(s)
- H C Davison
- Veterinary Parasitology, Liverpool School of Tropical Medicine/Faculty of Veterinary Science, University of Liverpool, UK
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24
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Abstract
Since the identification of Neospora caninum in 1984 as a parasite separate from Toxoplasma gondii by Bjerkas et al., and its subsequent characterization and classification in 1988 by Dubey and co-workers, this parasite has attracted increasing attention, primarily as an important causative agent of abortion in cattle and neuromuscular disease in dogs, but also as a complementary model system to T. gondii for investigating the basic biology of intracellular parasitism. During November 11-14, 1999, the COST 820 Annual meeting (Vaccines against coccidioses) took place in Interlaken, Switzerland. Almost half of the papers presented at that meeting were on N. caninum and neosporosis, reflecting the increasing awareness of the importance of this parasite on part of the scientific community in Europe. On the occasion of the meeting, participants in this COST Action involved in Neospora research in Europe were asked to participate in this invited review in order to document the growing interest in N. caninum and the disease it causes. Thus, this paper is a unique collection of contributions provided by several European experts in the field. It is comprised of 10 reviews or original papers on different aspects of Neospora research including epidemiology, immunology, application and development of serological tools, and molecular characterisation of the parasite currently carried out throughout Europe. In addition, two distinguished invited speakers from overseas (Milton McAllister and John Ellis) provided valuable contributions. This invited review demonstrates that the COST 820 Action has brought together scientists from all over Europe and other parts of the world, and has laid the basis for many fruitful collaborations. The studies described here will contribute in assessing the relevance of neosporosis as a potential risk factor not only for animals, but also for human health.
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Affiliation(s)
- A Hemphill
- Institute of Parasitology, University of Berne, Länggass-Strasse 122, CH-3012, Bern, Switzerland.
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25
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Baszler TV, Gay LJ, Long MT, Mathison BA. Detection by PCR of
Neospora caninum
in Fetal Tissues from Spontaneous Bovine Abortions. J Clin Microbiol 1999; 37:4059-64. [PMID: 10565932 PMCID: PMC85881 DOI: 10.1128/jcm.37.12.4059-4064.1999] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
The routine diagnosis of
Neospora caninum
abortion is based upon histopathologic changes in fetal tissues and identification of tissue parasites by immunohistochemistry. Confirmation of
N. caninum
infection by immunohistochemistry has low sensitivity. In the present study, we examined the utility of PCR in detecting
N. caninum
infection in fetal tissues from spontaneous bovine abortion. DNA was obtained from fresh and formalin-fixed tissues from 61 bovine fetuses submitted for abortion diagnosis. Histopathology and immunohistochemistry determined the true status of
N. caninum
infection in each fetus. In formalin-fixed paraffin-embedded tissues, PCR detected
N. caninum
DNA in 13 of 13 true-positive fetuses (100%) and in 1 of 16 true-negative fetuses (6%). In fresh or frozen tissues, PCR detected
N. caninum
DNA in 10 of 13 true-positive fetuses (77%) and 0 of 11 true-negative fetuses (0%). PCR also detected
N. caninum
DNA in 6 of 8 fetuses that had typical lesions of
N. caninum
but were immunohistochemistry negative, indicating a higher sensitivity of PCR in comparison to that of immunohistochemistry.
N. caninum
DNA was amplified most consistently from brain tissue. PCR detection of
N. caninum
DNA in formalin-fixed, paraffin-embedded tissues was superior to that in fresh tissues, presumably because of the increased accuracy of sample selection inherent in histologic specimens.
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Affiliation(s)
- T V Baszler
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040, USA.
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26
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Williams DJ, Davison HC, Helmick B, McGarry J, Guy F, Otter A, Trees AJ. Evaluation of a commercial ELISA for detecting serum antibody to Neospora caninum in cattle. Vet Rec 1999; 145:571-5. [PMID: 10606017 DOI: 10.1136/vr.145.20.571] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A commercially available serum antibody detection enzyme-linked immunosorbent assay for Neospora caninum in cattle was evaluated against an immunofluorescent antibody test (IFAT) by applying it to 397 sera from normal adult cattle, 352 sera from cattle which had recently aborted, and 422 sera from two herds which had a history of N caninum-associated abortions. It was evaluated in two laboratories and showed high reproducibility, repeatability and almost perfect or substantial agreement with the IFAT.
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Affiliation(s)
- D J Williams
- Veterinary Parasitology, Liverpool School of Tropical Medicine/Faculty of Veterinary Science, University of Liverpool
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27
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Davison HC, Otter A, Trees AJ. Estimation of vertical and horizontal transmission parameters of Neospora caninum infections in dairy cattle. Int J Parasitol 1999; 29:1683-9. [PMID: 10608455 DOI: 10.1016/s0020-7519(99)00129-0] [Citation(s) in RCA: 191] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Transmission parameters of Neospora caninum infections in dairy cattle were determined in six herds with a history of Neospora-associated abortions, using an antibody-detection ELISA to detect evidence of infection. A total of 124 seropositive dams and their calves were tested at calving to estimate vertical transmission, and 154 seronegative heifers were monitored prospectively from birth for evidence of post-natal infection. The probability of vertical transmission was very high; 95.2% (95% confidence interval: 89.8%, 98.2%) of the seropositive dams produced calves that were seropositive prior to consumption of colostrum. In the prospective study, three heifers seroconverted, by 1, 8 and 16 months of age, and the overall incidence rate of seroconversion was 1.9 per 100 heifer-years at risk, ranging from 0 to 4.1 per 100 heifer-years at risk within herds. If heifers with inconclusive ELISA results were included in the analysis, the incidence rate of seroconversion was 3.8 per 100 heifer-years at risk, ranging from 0 to 8.3 per 100 heifer-years at risk within herds. This study showed that vertical transmission was the major route involved in the spread of N. caninum in these herds, and that there was only a low detectable level of horizontal transmission. However, further studies are needed to provide parasitological evidence of infection in those heifers that seroconverted.
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Affiliation(s)
- H C Davison
- Veterinary Parasitology, Liverpool School of Tropical Medicine/Faculty of Veterinary Science, University of Liverpool, UK
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28
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French NP, Clancy D, Davison HC, Trees AJ. Mathematical models of Neospora caninum infection in dairy cattle: transmission and options for control. Int J Parasitol 1999; 29:1691-704. [PMID: 10608456 DOI: 10.1016/s0020-7519(99)00131-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The transmission and control of Neospora caninum infection in dairy cattle was examined using deterministic and stochastic models. Parameter estimates were derived from recent studies conducted in the UK and from the published literature. Three routes of transmission were considered: maternal vertical transmission with a high probability (0.95), horizontal transmission from infected cattle within the herd, and horizontal transmission from an independent external source. Putative infection via pooled colostrum was used as an example of within-herd horizontal transmission, and the recent finding that the dog is a definitive host of N. caninum supported the inclusion of an external independent source of infection. The predicted amount of horizontal transmission required to maintain infection at levels commonly observed in field studies in the UK and elsewhere, was consistent with that observed in studies of post-natal seroconversion (0.85-9.0 per 100 cow-years). A stochastic version of the model was used to simulate the spread of infection in herds of 100 cattle, with a mean infection prevalence similar to that observed in UK studies (around 20%). The distributions of infected and uninfected cattle corresponded closely to Normal distributions, with S.D.s of 6.3 and 7.0, respectively. Control measures were considered by altering birth, death and horizontal transmission parameters. A policy of annual culling of infected cattle very rapidly reduced the prevalence of infection, and was shown to be the most effective method of control in the short term. Not breeding replacements from infected cattle was also effective in the short term, particularly in herds with a higher turnover of cattle. However, the long-term effectiveness of these measures depended on the amount and source of horizontal infection. If the level of within-herd transmission was above a critical threshold, then a combination of reducing within-herd, and blocking external sources of transmission was required to permanently eliminate infection.
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Affiliation(s)
- N P French
- Department of Clinical Veterinary Science, University of Liverpool, Neston, South Wirral, UK.
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29
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Jensen AM, Björkman C, Kjeldsen AM, Wedderkopp A, Willadsen C, Uggla A, Lind P. Associations of Neospora caninum seropositivity with gestation number and pregnancy outcome in Danish dairy herds. Prev Vet Med 1999; 40:151-63. [PMID: 10423771 DOI: 10.1016/s0167-5877(99)00048-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The prevalence and distribution of seropositivity towards the protozoan parasite Neospora caninum were studied in single blood samples from 1561 cows from 31 Danish dairy herds. Blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test. Seroprevalence in 15 herds with previous abortions assigned to neosporosis ranged from 1% to 58%, with a mean frequency of 22%. In eight out of 16 herds without a history of N.caninum related abortions, no seroreactors were found. In the remaining eight herds, the seroprevalence ranged from 6% to 59%. The prevalence and distribution of seropositivity, gestation number prior to sampling, and breed were related to abortions and perinatal deaths using a random-effects logistic-regression model. Abortion risk was significantly increased in seropositive animals (OR = 3) and in > or = 2nd-gestation cows (OR = 3). Perinatal death was significantly influenced by gestation number and breed, but not by serostatus. Reproductive performance and culling risk of cows were not affected by serostatus. Seropositivity increased with "age" (i.e. gestation number) (P = 0.02). In open cows, seropositivity tended to decrease with distance from calving (P = 0.05). The proportion of seropositive pregnant cows increased with trimester (P = 0.02).
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Affiliation(s)
- A M Jensen
- Danish Agricultural Advisory Centre, Aarhus, Denmark.
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30
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Davison HC, French NP, Trees AJ. Herd-specific and age-specific seroprevalence of Neospora caninum in 14 British dairy herds. Vet Rec 1999; 144:547-50. [PMID: 10371011 DOI: 10.1136/vr.144.20.547] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
All the cattle in 14 dairy herds in England were tested for Neospora caninum-specific antibodies with a commercial ELISA. Three of the herds had had sporadic abortions, eight had had endemic abortions and three had had epidemic abortions associated with N caninum before the study. Of 4295 cattle tested, 17.1 per cent were seropositive and the herd-specific prevalence ranged from 7.3 per cent to 44.8 per cent. No significant effect of either herd size (P = 0.988), endemic (P = 0.869) or epidemic (P = 0.138) patterns of abortion on herd-specific prevalence was found by using logistic regression analysis. There was no evidence in any herd of a significant increase in prevalence with age; the prevalence in seven-to 12-month-old cattle was not significantly different (P > 0.400) from the prevalence in older cattle, except that there was a significantly lower prevalence (P = 0.017) in 13-to 24-month-old cattle. The results of this study are consistent with vertical transmission being the major route of N caninum transmission in these herds.
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Affiliation(s)
- H C Davison
- Department of Veterinary Clinical Science and Animal Husbandry, Faculty of Veterinary Science, University of Liverpool Veterinary Teaching Hospital, Leahurst, Neston, South Wirral
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31
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González L, Buxton D, Atxaerandio R, Aduriz G, Maley S, Marco JC, Cuervo LA. Bovine abortion associated with Neospora caninum in northern Spain. Vet Rec 1999; 144:145-50. [PMID: 10074662 DOI: 10.1136/vr.144.6.145] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
During 1996, aborted bovine fetuses from dairy herds in norther Spain were examined by histopathological, immunohistochemical and serological methods for evidence of infection by Neospora caninum. Microscopical brain changes consistent with those of neosporosis were detected in 36 of 81 fetuses and specific antibodies (IFAT titres > or = 1/16) in 32 of 63. Eight fetuses with neurological lesions were seronegative, and eight without lesions were seropositive. In 25 of 34 fetal brains with lesions consistent with published descriptions of neosporosis, immunohistochemical analysis revealed the presence of N caninum antigen. Depending on the diagnostic criteria, the prevalence of neosporosis related to bovine abortion was between 32 and 57 per cent of the fetuses submitted and between 33 and 58 per cent of the herds involved. Data on the geographical, seasonal and fetal age distribution of the infection are given for the fetuses examined and the value of the different diagnostic methods is discussed.
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Affiliation(s)
- L González
- Departamento de Patología Animal, SIMA-CIMA, Gobierno Vasco, Derio, Spain
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32
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Taylor MA, Webster KA. Recent advances in the diagnosis in livestock of Cryptosporidium, Toxoplasma, Giardia and other protozoa of veterinary importance. Res Vet Sci 1998; 65:183-93. [PMID: 9915141 PMCID: PMC7131700 DOI: 10.1016/s0034-5288(98)90141-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/1998] [Indexed: 01/23/2023]
Affiliation(s)
- M A Taylor
- Parasitology Discipline, Central Veterinary Laboratory, (Veterinary Laboratories Agency), New Haw, Addlestone, Surrey
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33
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Campero CM, Anderson ML, Conosciuto G, Odriozola H, Bretschneider G, Poso MA. Neospora caninum-associated abortion in a dairy herd in Argentina. Vet Rec 1998; 143:228-9. [PMID: 9770768 DOI: 10.1136/vr.143.8.228] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- C M Campero
- Patología Veterinaria, INTA, Balcarce, Argentina
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34
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Moen AR, Wouda W, Mul MF, Graat EA, van Werven T. Increased risk of abortion following Neospora caninum abortion outbreaks: a retrospective and prospective cohort study in four dairy herds. Theriogenology 1998; 49:1301-9. [PMID: 10732067 DOI: 10.1016/s0093-691x(98)00077-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Explosive abortion outbreaks in 4 Dutch dairy herds during 1992 to 1994 are reported. In 50 of 51 fetuses submitted during the first 3 wk of the outbreaks characteristic histological lesions compatible for infection with Neospora caninum were seen. Diagnosis of infection was confirmed by immunohistochemistry in 40 fetuses (78%). No evidence for other abortifacients was found. The abortion risk of the herds was investigated in a prospective and retrospective cohort study. The prospective study showed that cows aborting during the outbreaks and N. caninum seropositive nonaborting cows had a two- to three-fold increased risk of abortion compared with N. caninum seronegative cows. Retrospective examination showed that seropositive nonaborting cows had an increased risk of abortion before the outbreaks, which may indicate that these animals were infected with N. caninum prior to the outbreaks. It is concluded that serostatus can be used for selective culling of cows to decrease future risk of abortion in dairy herds.
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Affiliation(s)
- A R Moen
- Institute of Animal Science, Wageningen Agricultural University, The Netherlands
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35
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Buxton D, Maley SW, Wright S, Thomson KM, Rae AG, Innes EA. The pathogenesis of experimental neosporosis in pregnant sheep. J Comp Pathol 1998; 118:267-79. [PMID: 9651804 DOI: 10.1016/s0021-9975(07)80003-x] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Three groups of eight pregnant sheep were inoculated with tachyzoites of the NCl isolate of Neospora caninum at 45 (group 1), 65 (group 2) or 90 (group 3) days' gestation. A further six animals (group 4) served as controls. Fourteen of the infected ewes developed a fever, which in two cases was biphasic. In six ewes in group 1, the fetuses died and were resorbed, and in the other two the fetuses were aborted. In group 2, one ewe resorbed her fetus, six aborted dead fetuses and one produced a live lamb. In group 3, six ewes aborted and two produced one live and one stillborn lamb each. Thus, the stage of gestation influenced the outcome of infection. All but one of the ewes "seroconverted", as shown by enzyme-linked immunosorbent assay, and 10 of 13 fetal sera examined by an indirect immunofluorescent antibody test were positive. The polymerase chain reaction was also used to detect DNA of N. caninum in aborted tissues. Immunohistochemical examination showed that the parasite had invaded the placentas of all cases examined, displaying an apparent predilection for fetal chorionic epithelium and fetal placental blood vessels, as well as inducing thrombosis in some maternal caruncular blood vessels. Organisms were associated with fetal vasculitis, focal degeneration and inflammation of the chorioallantois, and widespread, severe focal necrosis in the placentome. Characteristic lesions were seen in the fetal brains, in addition to focal leucomalacia, thought to be due to anoxia resulting from the placental damage. The six control sheep in group 4 remained clinically healthy and produced normal uninfected lambs.
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Affiliation(s)
- D Buxton
- Moredun Research Institute, International Research Centre, Penicuik, Midlothian
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36
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Otter A, Jeffrey M, Scholes SF, Helmick B, Wilesmith JW, Trees AJ. Comparison of histology with maternal and fetal serology for the diagnosis of abortion due to bovine neosporosis. Vet Rec 1997; 141:487-9. [PMID: 9402719 DOI: 10.1136/vr.141.19.487] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An indirect fluorescent antibody test was applied to sera from normally calving and aborting cows and to samples of pleural fluid from their aborted calves, and the antibody titres were compared with histology and immunocytochemistry for the diagnosis of Neospora-associated abortion. Two groups of aborting cows and a third group of cows which had calved normally were used; group A consisted of 36 cows which aborted calves showing characteristic non-suppurative inflammatory lesions in which Neospora was demonstrated by immunocytochemistry, group B consisted of 100 cows which aborted calves without histological evidence of neosporosis, and group C consisted of 128 normally calved cows which were sampled within one month of calving. Serology on the maternal sera and fetal fluids was highly specific and sensitive for Neospora infection although 5 per cent of the cows which aborted Neospora-negative calves and 4.7 per cent of the normally calved cows were also seropositive. Anti-Neospora antibodies were also detected in 7 per cent of the samples of fetal fluid from Neospora-negative abortions.
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Affiliation(s)
- A Otter
- Veterinary Investigation Centre, Johnstown, Carmarthen
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37
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Jenkins MC, Wouda W, Dubey JP. Serological response over time to recombinant Neospora caninum antigens in cattle after a neosporosis-induced abortion. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1997; 4:270-4. [PMID: 9144362 PMCID: PMC170517 DOI: 10.1128/cdli.4.3.270-274.1997] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recombinant Neospora caninum tachyzoite antigens were evaluated in an enzyme-linked immunosorbent assay (ELISA) for recognition by serum antibodies (Ab) from Neospora-infected cattle. Serum samples were obtained every 2 to 3 weeks for 8 to 15 months from 10 cows with histories of Neospora-associated abortion. Serum samples were also obtained from offspring of these animals and from a large number of cows that had aborted a fetus, due to infection by Neospora or other organisms, at various times during gestation. All 10 cows had positive ELISA Ab titers to both recombinant N. caninum tachyzoite antigens after abortion, during subsequent gestation, and after parturition. In three cows, there was a noticeable peak in Ab titers early in gestation. Calves born to Neospora-infected cows also had positive titers of Ab to the recombinant tachyzoite antigens, and these titers remained elevated for at least 4 months after birth. A portion of the serum immunoglobulin in calves may have been derived from colostrum of infected cows. A calf born from a seronegative mother had a positive ELISA titer only after being fed colostrum from a seropositive cow. However, precolostral titers in calves born from Neospora-infected cows were high at birth, suggesting that the parasite was transmitted to the fetus via the placenta and induced a humoral immune response therein. The recombinant tachyzoite antigens were also useful for corroborating clinical diagnoses of Neospora-induced abortion. A significant difference (P < 0.05) between anti-recombinant antigen Ab titers in cows that aborted due to Neospora and those in cows that aborted from other causes was found.
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Affiliation(s)
- M C Jenkins
- Parasite Biology and Epidemiology Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA
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38
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Wouda W, Moen AR, Visser IJ, van Knapen F. Bovine fetal neosporosis: a comparison of epizootic and sporadic abortion cases and different age classes with regard to lesion severity and immunohistochemical identification of organisms in brain, heart, and liver. J Vet Diagn Invest 1997; 9:180-5. [PMID: 9211238 DOI: 10.1177/104063879700900212] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Eighty bovine fetuses with confirmed neosporosis were used to score lesion severity and presence of parasites in brain, heart, and liver. A comparison was made between epizootic and sporadic abortion cases. The possible influence of fetal age was also investigated. Histologic lesions of multifocal encephalitis, myocarditis, and periportal hepatitis with or without focal hepatocellular necrosis were almost always observed. Neospora caninum tachyzoites were identified immunohistochemically in 85% of the brains, 14% of the hearts, and 26% of the livers. Tissue cysts were observed in 21% of the brains. Significant differences between epizootic and sporadic abortion cases were found only in the liver. Hepatic lesions were more prominent and N. caninum tachyzoites were observed more frequently and in higher numbers in epizootic cases. Examination by immunohistochemistry of the liver in addition to the brain can be highly contributive diagnostically, particularly in epizootic cases. There were no significant age-related differences except for a higher presence of tachyzoites in the hearts of younger fetuses (3-4 months gestational age).
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Affiliation(s)
- W Wouda
- Animal Health Service, Drachten, The Netherlands
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39
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Williams DJ, McGarry J, Guy F, Barber J, Trees AJ. Novel ELISA for detection of Neospora-specific antibodies in cattle. Vet Rec 1997; 140:328-31. [PMID: 9106971 DOI: 10.1136/vr.140.13.328] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An enzyme-linked immunosorbent assay (ELISA) to detect antibodies to Neospora species in cattle was developed. Whole formalin-fixed Neospora caninum (NC-Liverpool) tachyzoites were used as antigen and a monoclonal antibody to bovine immunoglobulin light chain and an anti-mouse horseradish peroxidase conjugate were used to reveal bound antibody. A panel of 46 sera, negative by the immunofluorescent antibody test (IFAT), were used in the ELISA at a serum dilution of 1:500 to calculate the negative cut-off value of OD405 = 0.77. There was a 95 per cent agreement between the results of the ELISA and the IFAT with 104 serum samples. The specificity and sensitivity of the ELISA were 96 per cent and 95 per cent, respectively, when compared with the IFAT. No significant cross-reaction was observed with the sera from cattle infected experimentally with Toxoplasma gondii, Cryptosporidium parvum, Babesia divergens, Sarcocystis cruzi, Eimeria alabamensis or E bovis. A significantly modified version of the test is now commercially available.
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Affiliation(s)
- D J Williams
- Division of Parasite and Vector Biology, Liverpool School of Tropical Medicine/Faculty of Veterinary Science, University of Liverpool
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40
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Otter A, Wilson BW, Scholes SFE, Jeffrey M, Helmick B, Trees AJ. Results of a survey to determine whether Neospora
is a significant cause of ovine abortion in England and Wales. Vet Rec 1997. [DOI: 10.1136/vr.140.7.175] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- A. Otter
- Veterinary Investigation Centre; Job's Well Road, Johnstown Carmarthen SA31 3EZ
| | - B. W. Wilson
- Veterinary Investigation Centre; Barton Hall, Barton Preston Lancashire PR3 5HE
| | - S. F. E. Scholes
- Lasswade Veterinary Laboratory; Bush Estate Penicuik Midlothian EH26 OSA
| | - M. Jeffrey
- Lasswade Veterinary Laboratory; Bush Estate Penicuik Midlothian EH26 OSA
| | - B. Helmick
- Veterinary Investigation Centre; Job's Well Road, Johnstown Carmarthen SA31 3EZ
| | - A. J. Trees
- Veterinary Parasitology; School of Tropical Medicine and Faculty of Veterinary Science; University of Liverpool; Pembroke Place Liverpool L3 5QA
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Abstract
Neospora caninum is a recently recognized protozoan parasite of animals, which until 1988 was misidentified as Toxoplasma gondii. Its life cycle is unknown. Transplacental transmission is the only recognized mode of transmission. It has a wide host range, but its zoonotic potential is unknown. Neosporosis is a major cause of abortion in cattle in many countries. It is also an important cause of neuromuscular paralysis in dogs. This paper reviews information on parasite structure, life cycle, biology, clinical signs, diagnosis, treatment and control.
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Affiliation(s)
- J P Dubey
- Parasite Biology and Epidemiology Laboratory, US Department of Agriculture, BARC-East, Beltsville, MD 20705-2350, USA.
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42
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Graham DA, Smyth JA, McLaren IE, Ellis WA. Stillbirth/perinatal weak calf syndrome: serological examination for evidence of Neospora caninum infection. Vet Rec 1996; 139:523-4. [PMID: 8953695 DOI: 10.1136/vr.139.21.523] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- D A Graham
- Veterinary Sciences Division, Department of Agriculture for Northern Ireland, Stormont, Belfast
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43
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Abstract
An indirect immunofluorescent antibody test (IFAT) and an enzyme-linked immunosorbent assay (ELISA) for specific anti-Neospora antibodies in bovine sera and foetal fluids were compared with histological examination results on aborted foetal material. The agreement between serological and histological examination results was poor, while the two serological tests showed a high degree of agreement. Serological testing of diagnostic serum samples and foetal fluids suggests that the prevalence of anti-Neospora antibodies in cattle which recently aborted is around 40%, in line with previous estimates of the number of abortions in dairy cattle caused by Neospora sp. A sero-epidemiological approach to the diagnosis of Neospora abortions in cattle may be suggested from these data.
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Affiliation(s)
- M P Reichel
- Central Animal Health Laboratory, Wallaceville, PO Box 40063, Upper Hutt, New Zealand.
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44
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Baszler TV, Knowles DP, Dubey JP, Gay JM, Mathison BA, McElwain TF. Serological diagnosis of bovine neosporosis by Neospora caninum monoclonal antibody-based competitive inhibition enzyme-linked immunosorbent assay. J Clin Microbiol 1996; 34:1423-8. [PMID: 8735092 PMCID: PMC229036 DOI: 10.1128/jcm.34.6.1423-1428.1996] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Neospora caninum, a protozoan parasite closely related to Toxoplasma gondii, causes abortion and congenital infection in cattle. To investigate specific methods of antemortem diagnosis, the antibody responses of infected cows were evaluated by immunoblot assay and competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA) by using a monoclonal antibody (MAb), MAb 4A4-2, against N. caninum tachyzoites. MAb 4A4-2 bound diffusely to the exterior surface of N. caninum tachyzoites and recognized a single 65-kDa band in immunoblots. MAb 4A4-2 was unreactive to antigens of two closely related apicomplexan protozoa, Toxoplasma gondii and Sarcocystis cruzi. Binding of MAb 4A4-2 was inhibited by mild periodate treatment of N. caninum antigen, demonstrating the carbohydrate nature of the epitope. Immunoblot analysis of N. caninum tachyzoite antigens with sera from cows with confirmed Neospora-induced abortion revealed at minimum 14 major antigens ranging from 11 to 175 kDa. Although the recognized antigens varied from cow to cow, antigens of 116, 65, and 25 kDa were detected in all cows with abortion confirmed to be caused by N. caninum. The binding of MAb 4A4-2 to N. caninum tachyzoite antigen was consistently inhibited by sera from Neospora-infected cows in a CI-ELISA format and was not inhibited by sera from Neospora antibody-negative cows. Furthermore, sera from cattle experimentally infected with T. gondii, S. cruzi, Sarcocystis hominis, or Sarcocystis hirsuta, which had cross-reactive antibodies recognizing multiple N. caninum antigens by immunoblot assay, did not inhibit binding of MAb 4A4-2 in the CI-ELISA. Thus, MAb 4A4-2 binds a carbohydrate epitope on a single N. caninum tachyzoite surface antigen that is recognized consistently and specifically by Neospora-infected cattle.
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Affiliation(s)
- T V Baszler
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040, USA.
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45
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Lally NC, Jenkins MC, Dubey JP. Evaluation of two Neospora caninum recombinant antigens for use in an enzyme-linked immunosorbent assay for the diagnosis of bovine neosporosis. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1996; 3:275-9. [PMID: 8705668 PMCID: PMC170329 DOI: 10.1128/cdli.3.3.275-279.1996] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Neospora caninum is a recently described apicomplexan parasite which causes paralysis and death in dogs. Neospora parasites also cause abortion and neonatal morbidity in cattle, sheep, goats, and horses, and neosporosis is emerging as an important cause of bovine abortion worldwide. The purpose of this study was to identify N. caninum cDNA clones encoding antigens that would be useful for the immunodiagnosis of bovine neosporosis. Two N. caninum tachyzoite cDNA clones expressing antigens that were recognized by serum from naturally and experimentally infected cattle were identified. The DNA sequences of these clones were determined, and the inserts were subcloned into the plasmid expression vector pTrcHisB. Both recombinant antigens, expressed as fusion proteins with a His6 tag, were purified on a nickel-chelating affinity column and evaluated in separate enzyme-linked immunosorbent assays (ELISAs). Both recombinant antigen ELISAs were capable of distinguishing between sera from Neospora-infected cows and sera from uninfected control cows. Furthermore, both assays were able to detect an antibody response in animals that were experimentally inoculated with N. caninum. Neither antigen showed evidence of cross-reactivity with serum from animals inoculated with the closely related parasites Toxoplasma gondii, Sarcocystis cruzi, Sarcocystis hominis, and Sarcocystis hirsuta.
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Affiliation(s)
- N C Lally
- Parasite Immunobiology Laboratory, USDA Agricultural Research Service, Beltsville, Maryland 20705, USA
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46
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McNamee PT, Trees AJ, Guy F, Moffett D, Kilpatrick D. Diagnosis and prevalence of neosporosis in cattle in Northern Ireland. Vet Rec 1996; 138:419-20. [PMID: 8733183 DOI: 10.1136/vr.138.17.419] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- P T McNamee
- Veterinary Sciences Division, Department of Agriculture for Northern Ireland, Omagh, County Tyrone
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