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Experimental infection with Neospora caninum in Texel ewes at different stages of gestation. Vet Parasitol Reg Stud Reports 2023; 37:100817. [PMID: 36623898 DOI: 10.1016/j.vprsr.2022.100817] [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: 03/02/2022] [Revised: 11/09/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022]
Abstract
In this study Texel sheep, at different stages of pregnancy, were experimentally infected with Neospora caninum. Eleven ewes, seronegative for N. caninum and Toxoplasma gondii, were inoculated 30 days before breeding (Group A), or at 65, 100, and 120 days of gestation (Groups B, C, and D). The group E (control) was inoculated with PBS. Blood samples were collected at -2, 2, 5, and 7 days post-infection (dpi), and weekly up to 42 dpi, for hematology, parasitemia (PCR), and serology (RIFI) assessments. Blood and tissue samples were collected from the lambs for molecular and histological analyses. All animals in Groups B, C, and D were seroconverted, whilst those in groups A and E remained seronegative. Parasitic DNA was detected in the blood of two ewes (groups B and D) and a lamb (group D), and in the brain of a lamb (group B). The parasitemia-positive ewe in group B delivered a weak and seropositive lamb, and had parasitic DNA in its placenta. These results confirm the vertical transmission of N. caninum in ewes inoculated at the beginning and end of pregnancy. The absence of abortions and other clinical signs suggest that Texel sheep may potentially have resistance to N. caninum.
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Khodadadi A, Malekifard F, Batavani RA. Investigation of Toxoplasma gondii and Neospora caninum as cause of ovine abortion in affected flocks of Urmia, northwest of Iran. BULGARIAN JOURNAL OF VETERINARY MEDICINE 2022. [DOI: 10.15547/bjvm.2020-0104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Toxoplasma gondii and Neospora caninum, two obligatory intracellular protozoan parasites, are important causes of neonatal mortality and abortion in farmed ruminants worldwide. Previously, protozoan abortions in small ruminants were attributed to T. gondii, but the role of N. caninum in these abortions was uncertain. The aim of this study was to investigate the role of T. gondii and N. caninum in ovine abortion in Urmia, northwest of Iran using a molecular method. Overall, 130 placenta and brain samples of aborted ovine foetuses were collected. Extracted DNA from placenta and CNS tissues of the aborted foetuses were analysed using PCR with primers specific for T. gondii and N. caninum. The association of the frequency of T. gondii and N. caninum infection of aborted foetuses with age and breed in flocks was also studied. The results showed that out of the 130 examined ovine foetuses, 5.3 and 2.3 % were PCR-positive for T. gondii and N. caninum DNA, respectively. In this study, no significant differences were recorded relating to Toxoplasma and Neospora infection in different age groups in flocks and among sheep breeds included in the present study (P>0.05). The results of this study proved the importance of T. gondii and N. caninum as reasons of abortion in the studied area.
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Affiliation(s)
- A. Khodadadi
- Department of Pathobiology Faculty of Veterinary Medicine, Urmia University, Urmia, West Azarbaijan, Iran
| | - F. Malekifard
- Department of Pathobiology Faculty of Veterinary Medicine, Urmia University, Urmia, West Azarbaijan, Iran
| | - R. A. Batavani
- Department of Theriogenology; Faculty of Veterinary Medicine, Urmia University, Urmia, West Azarbaijan, Iran
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Tuo W, Feng X, Cao L, Vinyard B, Dubey JP, Fetterer R, Jenkins M. Vaccination with Neospora caninum-cyclophilin and -profilin confers partial protection against experimental neosporosis-induced abortion in sheep. Vaccine 2021; 39:4534-4544. [PMID: 34176703 DOI: 10.1016/j.vaccine.2021.06.032] [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: 03/05/2021] [Revised: 06/02/2021] [Accepted: 06/12/2021] [Indexed: 11/16/2022]
Abstract
The purpose of this study was to evaluate the protective efficacy of a vaccine consisting of recombinant Neospora caninum-cyclophilin (NcCyP) and -profilin (NcPro) in sheep. At 42 d and 21 d prior to mating, adult Dorset ewes were immunized with the rNcCyP-rNcPro vaccine (Group 1) or co-purifying non-recombinant (NR) control vaccine (Group 2). At 90 days post-mating, all immunized ewes and were challenged by intravenous injection with 106Nesopora caninum Illinois tachyzoites (NcTZ). Significant protection (P < 0.05) was observed in Group 1 with 9 out of 13 ewes giving birth to live-born lambs (69.2%), whereas all Group 2 ewes aborted (6/6). Neospora caninum was detected by PCR in both fetal and placental tissues from all Group 2 aborting ewes and in the placental tissues of Group 1 aborting ewes. In contrast, tissues and placentas of Group 1 live-born lambs were Neospora DNA-negative. Immunoreactive Neospora antigens were demonstrated in placentas associated with abortions, but not in tissues of aborted fetuses or those of the live-born lambs and their associated placentas. Anti-NcCyP and anti-NcPro titers were high in sera from Group 1 ewes and were further boosted by challenge infection, resulting in long-lasting (≥14.5 mos.) elevated titers. Lambs born to Group 1 ewes also had high NcCyP and NcPro titers in pre-colostrum sera. Immunofluorescence staining (IFA) of NcTZ with Group 1 post-immunization sera revealed both surface and internal TZ staining, a pattern consistent with that observed with rabbit sera to rNcCyP or rNcPro. Infection of NR-vaccinated ewes produced high but transient anti-NcCyP and anti-NcPro Ab titers. The results indicate that the NcCyP-NcPro vaccine elicited strong anti-N. caninum responses and conferred significant protection against abortion and transplacental transmission of N. caninum TZ in sheep.
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Affiliation(s)
- Wenbin Tuo
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, MD 20705, United States
| | - Xiaosheng Feng
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Lili Cao
- Academy of Animal Sciences and Technology, Changchun, China
| | | | - J P Dubey
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, MD 20705, United States
| | - Raymond Fetterer
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, MD 20705, United States
| | - Mark Jenkins
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, MD 20705, United States.
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Meixner N, Sommer MF, Scuda N, Matiasek K, Müller M. Comparative aspects of laboratory testing for the detection of Toxoplasma gondii and its differentiation from Neospora caninum as the etiologic agent of ovine abortion. J Vet Diagn Invest 2020; 32:898-907. [PMID: 33025842 DOI: 10.1177/1040638720962110] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Histologic examination of aborted material is an essential component in the diagnosis of ovine toxoplasmosis. However, the detection of Toxoplasma gondii in histologic sections, and its differentiation from the closely related protozoan Neospora caninum, is challenging. We developed a chromogenic in situ hybridization (ISH) assay for the identification of T. gondii in paraffin-embedded tissue samples. We examined retrospectively the archived placental tissue of 200 sheep abortion submissions for the presence of T. gondii by immunohistochemistry (IHC), ISH, and real-time PCR (rtPCR). All placental samples that tested positive for T. gondii by rtPCR (9 of 200) were also positive by IHC, with inconclusive IHC staining in an additional 7 rtPCR-negative cases. Further testing for N. caninum of all 200 placentas by rtPCR revealed 7 Neospora-positive cases. T. gondii ISH was positive in 4 of 9 IHC-positive samples and 1 of the 7 N. caninum rtPCR-positive samples. Real-time PCR was used as the reference standard for specificity and sensitivity calculations regarding placenta samples. Specificity of ISH and IHC was 99% and 96-100%, respectively. The sensitivity of ISH (44%) was quite low compared to IHC (100%). The exclusive use of ISH for the detection of T. gondii, and thus for the diagnosis of ovine toxoplasmosis, was not acceptable. However, combined with rtPCR, both ISH and IHC can be useful detection methods to improve histologic evaluation by visualizing the parasite within tissue sections.
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Affiliation(s)
- Nicola Meixner
- Bavarian Health and Food Safety Authority, Erlangen, Germany
| | - Marie F Sommer
- Bavarian Health and Food Safety Authority, Erlangen, Germany
| | - Nelly Scuda
- Bavarian Health and Food Safety Authority, Erlangen, Germany
| | - Kaspar Matiasek
- Section of Clinical and Comparative Neuropathology, Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Matthias Müller
- Bavarian Health and Food Safety Authority, Erlangen, Germany
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Novoa MB, Aguirre NP, Ormaechea N, Palmero S, Rouzic L, Valentini BS, Sarli M, Orcellet VM, Marengo R, Vanzini VR, Primo ME. Validation and field evaluation of a competitive inhibition ELISA based on the recombinant protein tSAG1 to detect anti-Neospora caninum antibodies in sheep and goats. Vet Parasitol 2020; 284:109201. [PMID: 32801057 DOI: 10.1016/j.vetpar.2020.109201] [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: 06/09/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 10/23/2022]
Abstract
Neospora caninum is a protozoan parasite that causes abortion and reproductive failure in small ruminants. We validated and evaluated under field conditions a competitive inhibition ELISA based on the truncated SAG1 protein (tSAG1) from N. caninum for the detection of anti-N. caninum antibodies in sheep and goat flocks. The assay was validated using 80 positive and 142 negative serum samples from sheep and goats analyzed by IFAT and immunoblot (IB). ciELISAtSAG1 was then used to evaluate the prevalence of anti-N. caninum antibodies in 1449 goats from 143 flocks and 385 sheep from 40 flocks and compared to IFAT. The prevalence of anti-Toxoplasma gondii antibodies was evaluated by IFAT. The ciELISAtSAG1 cut-off was ≥ 36 percent inhibition, with a diagnostic sensitivity of 100.0 % (95 % CI = 95.4-100.0 %) and a diagnostic specificity of 98.6 % (95 % CI = 95.0-99.8 %) relative to the agreement between IFAT and IB. The field evaluation revealed a concordance between ciELISAtSAG1 and IFAT of 97.4 %, with an agreement (κ) of 0.90 for sheep sera, and a concordance of 96.5 % with κ = 0.85 for goat sera. The overall prevalence of anti-N. caninum antibodies in sheep was 14.3 % by IFAT and 15.8 % by ciELISAtSAG1. In goats, prevalence was 12.9 % by IFAT and 14.6 % by ciELISAtSAG1. The overall prevalence of anti-T. gondii antibodies was 28.8 % in goats and 43.8 % in sheep. The ciELISAtSAG1 could be useful for large-scale detection of anti-N. caninum antibodies in sheep and goats, and for seroepidemiological investigations due to its appropriate sensitivity and specificity, and the simplicity of production.
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Affiliation(s)
- María Belén Novoa
- Laboratory of Veterinary Immunology and Parasitology, National Institute of Agricultural Technology (INTA), Rafaela Agricultural Experimental Station, National Route 34, Km 227 (2300), Rafaela, Santa Fe, Argentina; National Scientific and Technical Research Council (CONICET), Santa Fe, Argentina.
| | - Nerina Patricia Aguirre
- Laboratory of Veterinary Immunology and Parasitology, National Institute of Agricultural Technology (INTA), Rafaela Agricultural Experimental Station, National Route 34, Km 227 (2300), Rafaela, Santa Fe, Argentina
| | - Nadia Ormaechea
- Faculty of Veterinary Science, National University of the Littoral (UNL), Kreder 2805 (S3080HOF), Esperanza, Santa Fe, Argentina
| | - Sebastián Palmero
- Faculty of Veterinary Science, National University of the Littoral (UNL), Kreder 2805 (S3080HOF), Esperanza, Santa Fe, Argentina
| | - Lisandro Rouzic
- Faculty of Veterinary Science, National University of the Littoral (UNL), Kreder 2805 (S3080HOF), Esperanza, Santa Fe, Argentina
| | - Beatriz Susana Valentini
- Laboratory of Veterinary Immunology and Parasitology, National Institute of Agricultural Technology (INTA), Rafaela Agricultural Experimental Station, National Route 34, Km 227 (2300), Rafaela, Santa Fe, Argentina
| | - Macarena Sarli
- Laboratory of Veterinary Immunology and Parasitology, National Institute of Agricultural Technology (INTA), Rafaela Agricultural Experimental Station, National Route 34, Km 227 (2300), Rafaela, Santa Fe, Argentina; National Scientific and Technical Research Council (CONICET), Santa Fe, Argentina
| | - Viviana Mercedes Orcellet
- Faculty of Veterinary Science, National University of the Littoral (UNL), Kreder 2805 (S3080HOF), Esperanza, Santa Fe, Argentina
| | - Rafael Marengo
- Faculty of Veterinary Science, National University of the Littoral (UNL), Kreder 2805 (S3080HOF), Esperanza, Santa Fe, Argentina
| | - Victor René Vanzini
- Laboratory of Veterinary Immunology and Parasitology, National Institute of Agricultural Technology (INTA), Rafaela Agricultural Experimental Station, National Route 34, Km 227 (2300), Rafaela, Santa Fe, Argentina
| | - María Evangelina Primo
- Laboratory of Veterinary Immunology and Parasitology, National Institute of Agricultural Technology (INTA), Rafaela Agricultural Experimental Station, National Route 34, Km 227 (2300), Rafaela, Santa Fe, Argentina; National Scientific and Technical Research Council (CONICET), Santa Fe, Argentina
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Diezma-Díaz C, Ferre I, Saldias B, Blanco-Murcia J, Ortega-Mora LM, Álvarez-García G. Added value of IgM detection and low avidity index as markers of acute bovine besnoitiosis. Vet Parasitol 2019; 277:109012. [PMID: 31884316 DOI: 10.1016/j.vetpar.2019.109012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 12/17/2022]
Abstract
Early in vivo diagnosis of bovine besnoitiosis is crucial for the success of control programmes. However, diagnosis in acutely infected animals is hindered by the low sensitivity of the available serological tools. In this study, a novel ELISA to detect specific anti-Besnoitia besnoiti IgM antibodies was developed. The usefulness of this tool together with an avidity ELISA were studied with a well-coded sera panel from experimentally and naturally infected cattle. First, the kinetics of specific IgM levels were determined in experimentally infected calves during the acute and chronic infection. Next, IgM levels were determined in naturally infected cattle with either acute or chronic infection. Finally, the IgG avidity index was monitored in both experimentally and naturally infected cattle. Specific IgM antibodies were detected prior to specific IgG antibodies (7-19 days vs. 17-26 days post-infection). A prompt IgM response was associated with the end of the febrile stage in experimentally infected calves. Naturally and experimentally infected animals with acute clinical signs tested IgM-positive but IgG-negative, followed by IgG seroconversion 2-3 weeks later. Chronically infected cattle developed both IgM and IgG specific antibodies. Moreover, a progressive increase in the avidity index (AI) was observed in all experimentally infected calves during the course of the experimental trials. However, a low AI coincided with visible tissue cysts. Low avidity values were also detected when naturally infected cattle with acute clinical signs seroconverted, in contrast to a high AI detected in chronically infected cattle. In summary, IgM and avidity ELISAs improved the early in vivo diagnosis of bovine besnoitiosis. IgM-positive but IgG-negative results were indicative of an acute infection, whereas IgG positive results accompanied by low avidity values confirmed a recent infection.
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Affiliation(s)
- Carlos Diezma-Díaz
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Ignacio Ferre
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Begonia Saldias
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Javier Blanco-Murcia
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain; Animal Medicine and Surgery Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Gema Álvarez-García
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
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Sánchez-Sánchez R, Ferre I, Re M, Regidor-Cerrillo J, Blanco-Murcia J, Ferrer LM, Navarro T, Pizarro Díaz M, González-Huecas M, Tabanera E, Benavides J, Ortega-Mora LM. Influence of dose and route of administration on the outcome of infection with the virulent Neospora caninum isolate Nc-Spain7 in pregnant sheep at mid-gestation. Vet Res 2018; 49:42. [PMID: 29739449 PMCID: PMC5941812 DOI: 10.1186/s13567-018-0539-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/06/2018] [Indexed: 11/01/2022] Open
Abstract
Experimental infections in pregnant sheep have been focused on studying the effect of the time of challenge on the outcome of N. caninum infection, whereas the impact of the dose and route of challenge has not been studied in depth. Therefore, clinical outcome, immune responses, parasite detection and burden, and lesion severity in placental tissues and foetal brains were investigated in 90-day-pregnant sheep inoculated intravenously with 105 (G1), 104 (G2), 103 (G3), or 102 (G4) tachyzoites or subcutaneously with 104 (G5) tachyzoites of the virulent Nc-Spain7 isolate and an uninfected group (G6). Comparing challenge doses, G1 was the only group that had 100% abortion. Likewise, IFNγ levels in G1 increased earlier than those in other intravenously infected groups, and IgG levels on day 21 post-infection (pi) were higher in G1 than those in other intravenously infected groups. Concerning vertical transmission, G1 shows a higher parasite burden in the foetal brain than did G2 and G3. Comparing routes of administration, no differences in foetal survival rate or parasite load in the foetal brain were found. Although G2 had higher IFNγ levels than G5 on day 10 pi, no differences were found in humoral immune responses. Because the outcome after intravenous infection with 105 tachyzoites was similar to that observed after intravenous infection with 106 tachyzoites used in a previous work (100% abortion and vertical transmission), we conclude that it may be reasonable to use 105 tachyzoites administered by the intravenous route in further experiments when assessing drugs or vaccine candidates.
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Affiliation(s)
- Roberto Sánchez-Sánchez
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Ignacio Ferre
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Michela Re
- Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Javier Regidor-Cerrillo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Javier Blanco-Murcia
- Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Luis Miguel Ferrer
- Departamento de Patología Animal, Facultad de Veterinaria, C/Miguel Servet 177, 50013, Zaragoza, Spain
| | - Teresa Navarro
- Departamento de Patología Animal, Facultad de Veterinaria, C/Miguel Servet 177, 50013, Zaragoza, Spain
| | - Manuel Pizarro Díaz
- Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Marta González-Huecas
- Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Enrique Tabanera
- Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Julio Benavides
- Livestock Health and Production Institute (ULE-CSIC), 24346, León, Spain
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
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Klauck V, Pazinato R, Radavelli WM, Custódio E, Bianchi AE, Camillo G, Cezar AS, Vogel FF, Tonin AA, Ferreira R, Stefani LM, Da Silva AS. Toxoplasma gondii infection in dairy ewes: Vertical transmission and influence on milk production and reproductive performance. Microb Pathog 2016; 99:101-105. [DOI: 10.1016/j.micpath.2016.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 08/08/2016] [Accepted: 08/10/2016] [Indexed: 11/27/2022]
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Nakagaki KY, Abreu CC, Costa RC, Orlando DR, Freire LR, Bruhn FR, Peconick AP, Wouters F, Wouters AT, Raymundo DL, Varaschin MS. Lesions and distribution of Neospora caninum in tissues of naturally infected female goats. Small Rumin Res 2016. [DOI: 10.1016/j.smallrumres.2016.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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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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11
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Approaches for the vaccination and treatment of Neospora caninum infections in mice and ruminant models. Parasitology 2015; 143:245-59. [PMID: 26626124 DOI: 10.1017/s0031182015001596] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Neospora caninum is a leading cause of abortion in cattle, and is thus an important veterinary health problem of high economic significance. Vaccination has been considered a viable strategy to prevent bovine neosporosis. Different approaches have been investigated, and to date the most promising results have been achieved with live-attenuated vaccines. Subunit vaccines have also been studied, and most of them represented components that are functionally involved in (i) the physical interaction between the parasite and its host cell during invasion or (ii) tachyzoite-to-bradyzoite stage conversion. Drugs have been considered as an option to limit the effects of vertical transmission of N. caninum. Promising results with a small panel of compounds in small laboratory animal models indicate the potential value of a chemotherapeutical approach for the prevention of neosporosis in ruminants. For both, vaccines and drugs, the key for success in preventing vertical transmission lies in the application of bioactive compounds that limit parasite proliferation and dissemination, without endangering the developing fetus not only during an exogenous acute infection but also during recrudescence of a chronic infection. In this review, the current status of vaccine and drug development is presented and novel strategies against neosporosis are discussed.
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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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Arranz-Solís D, Benavides J, Regidor-Cerrillo J, Fuertes M, Ferre I, Ferreras MDC, Collantes-Fernández E, Hemphill A, Pérez V, Ortega-Mora LM. Influence of the gestational stage on the clinical course, lesional development and parasite distribution in experimental ovine neosporosis. Vet Res 2015; 46:19. [PMID: 25884945 PMCID: PMC4346111 DOI: 10.1186/s13567-014-0139-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/15/2014] [Indexed: 11/10/2022] Open
Abstract
Neospora caninum is considered one of the main causes of abortion in cattle, yet recent studies have also emphasised its relevance as an abortifacient in small ruminants. In order to gain deeper insight into the pathogenesis of ovine neosporosis, pregnant ewes were intravenously inoculated with 106 tachyzoites of the Nc-Spain7 isolate at days 40, 90 or 120 of gestation. Infection during the first term resulted in the death of all foetuses between days 19 and 21 post-infection, showing mainly necrotic lesions in foetal liver and the highest parasite DNA detection and burden in both placenta and foetal viscera. After infection at day 90, foetal death was also detected in all ewes, although later (34–48 days post-infection). In this group, lesions were mainly inflammatory. Foetal livers showed the lowest frequency of lesions, as well as the lowest parasite detection and burden. All ewes infected at day 120 delivered viable lambs, although 3 out of 9 showed weakness and recumbency. Neospora DNA was detected in all lambs but one, and parasite burden was similar to that observed in day 90 group. Lesions in this group showed more conspicuous infiltration of inflammatory cells and higher frequency in foetal brain and muscle when compared to both previous groups. These results highlight the crucial role that the stage of gestation plays on the course of ovine neosporosis, similar to that reported in bovine neosporosis, and open the doors to consider sheep as a valid model for exogenous transplacental transmission for ruminant neosporosis.
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Affiliation(s)
- David Arranz-Solís
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Julio Benavides
- Livestock Health and Production Institute (ULE-CSIC), 24346, León, Spain.
| | - Javier Regidor-Cerrillo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Miguel Fuertes
- Livestock Health and Production Institute (ULE-CSIC), 24346, León, Spain.
| | - Ignacio Ferre
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | | | - Esther Collantes-Fernández
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
| | - Andrew Hemphill
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, CH-3012, Bern, Switzerland.
| | - Valentín Pérez
- Livestock Health and Production Institute (ULE-CSIC), 24346, León, Spain.
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
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Syed-Hussain SS, Howe L, Pomroy WE, West DM, Hardcastle M, Williamson NB. Vertical transmission in experimentally infected sheep despite previous inoculation with Neospora caninum NcNZ1 isolate. Vet Parasitol 2015; 208:150-8. [PMID: 25638717 DOI: 10.1016/j.vetpar.2014.12.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 11/22/2014] [Accepted: 12/31/2014] [Indexed: 11/26/2022]
Abstract
Recent reports indicate N. caninum has a possible role in causing abortions in sheep in New Zealand. Knowledge about the mode of transmission of neosporosis in sheep in New Zealand is limited. This study aimed to determine the rate of vertical transmission that would occur in lambs born from experimentally inoculated ewes and to determine if previous inoculation would protect the lambs from N. caninum infection. A group of 50 ewes was divided into 2 groups with one group being inoculated with 5×10(6) N. caninum tachyzoites prior to pregnancy in Year 1. In Year 2, each of these groups was subdivided into 2 groups with one from each original group being inoculated with 1×10(7) N. caninum tachyzoites on Day 120 of gestation. Inoculation of N. caninum tachyzoites into ewes prior to mating resulted in no congenital transmission in lambs born in Year 1 but without further inoculation, 7 out of 11 lambs in Year 2 were positive for N. caninum infection. Ewes that were inoculated in both years resulted in all 12 lambs born in Year 2 being positive for N. caninum infection. This indicates that previous inoculation in Year 1 did not result in any vertical transmission in that year but did not provide any protection against vertical transmission in Year 2. These results suggest that vertical transmission occurs readily once the ewe is infected.
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Affiliation(s)
- S S Syed-Hussain
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - L Howe
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - W E Pomroy
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand.
| | - D M West
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - M Hardcastle
- Gribbles Veterinary Pathology, PO Box 12049, Penrose, Auckland 1642, New Zealand
| | - N B Williamson
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
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15
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Costa RC, Orlando DR, Abreu CC, Nakagaki KYR, Mesquita LP, Nascimento LC, Silva AC, Maiorka PC, Peconick AP, Raymundo DL, Varaschin MS. Histological and immunohistochemical characterization of the inflammatory and glial cells in the central nervous system of goat fetuses and adult male goats naturally infected with Neospora caninum. BMC Vet Res 2014; 10:291. [PMID: 25495444 PMCID: PMC4270032 DOI: 10.1186/s12917-014-0291-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 11/25/2014] [Indexed: 12/03/2022] Open
Abstract
Background Neospora caninum is an apicomplexan protozoan that is considered one of the main agents responsible for abortion in ruminants. The lesions found in the central nervous system (CNS) of aborted fetuses show multifocal necrosis, gliosis, and perivascular cuffs of mononuclear cells, but the inflammatory and glial cells have not been immunophenotypically characterized. The lesions in the CNS of infected adult animals have rarely been described. Therefore, in this study, we characterized the lesions, the immunophenotypes of the inflammatory and glial cells and the expression of MHC-II and PCNA in the CNS of goats infected with N. caninum. The CNS of eight aborted fetuses and six adult male goats naturally infected with N. caninum were analyzed with lectin histochemistry (RCA1) and immunohistochemistry (with anti-CD3, −CD79α, −GFAP, −MHC-II, and -PCNA antibodies). All animals were the offspring of dams naturally infected with N. caninum. Results The microscopic lesions in the CNS of the aborted fetuses consisted of perivascular cuffs composed mainly of macrophages (RCA1+), rare T lymphocytes (CD3+), and rare B lymphocytes (CD79α+). Multifocal necrosis surrounded by astrocytes (GFAP+), gliosis composed predominantly of monocytic-lineage cells (macrophages and microglia, RCA1+), and the cysts of N. caninum, related (or not) to the lesions were present. Similar lesions were found in four of the six male goats, and multinucleate giant cells related to focal gliosis were also found in three adult goats. Anti-GFAP immunostaining showed astrocytes characterizing areas of glial scarring. Cysts of N. caninum were found in three adult male goats. The presence of N. caninum was evaluated with histopathology, immunohistochemistry, and PCR. Immunohistochemistry demonstrated anti-PCNA labeling of macrophages and microglia in the perivascular cuffs and the expression of MHC-II by microglia and endothelial cells in the CNS of the aborted fetuses and adult male goats. Conclusions Macrophages and microglia were the predominant inflammatory cells in the CNS of aborted fetuses and healthy adult male goats infected with N. caninum. Activated astrocytes were mainly associated with inflamed areas, suggesting that astrocytes were involved in the resolution of the lesions.
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Affiliation(s)
- Rafael Carneiro Costa
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | - Débora Ribeiro Orlando
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | - Camila Costa Abreu
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | | | - Leonardo Pereira Mesquita
- Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Av. Prof. Dr. Orlando Marques de Paiva, 87 - Cidade Universitária, São Paulo, SP, Brazil.
| | - Lismara Castro Nascimento
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | - Aline Costa Silva
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | - Paulo César Maiorka
- Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Av. Prof. Dr. Orlando Marques de Paiva, 87 - Cidade Universitária, São Paulo, SP, Brazil.
| | - Ana Paula Peconick
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | - Djeison Lutier Raymundo
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
| | - Mary Suzan Varaschin
- Universidade Federal de Lavras, Setor de Patologia Veterinária, Caixa postal 3037, Lavras, MG, Brazil.
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16
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Katzer F, Canton G, Burrells A, Palarea-Albaladejo J, Horton B, Bartley PM, Pang Y, Chianini F, Innes EA, Benavides J. Immunization of lambs with the S48 strain of Toxoplasma gondii reduces tissue cyst burden following oral challenge with a complete strain of the parasite. Vet Parasitol 2014; 205:46-56. [DOI: 10.1016/j.vetpar.2014.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/27/2014] [Accepted: 07/01/2014] [Indexed: 10/25/2022]
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17
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González-Warleta M, Castro-Hermida JA, Regidor-Cerrillo J, Benavides J, Álvarez-García G, Fuertes M, Ortega-Mora LM, Mezo M. Neospora caninum infection as a cause of reproductive failure in a sheep flock. Vet Res 2014; 45:88. [PMID: 25158756 PMCID: PMC4153895 DOI: 10.1186/s13567-014-0088-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/08/2014] [Indexed: 02/04/2023] Open
Abstract
Neospora caninum has been detected only sporadically in cases of ovine abortion, and it has therefore traditionally been considered as an unimportant parasite in small ruminants. This study was carried out with the aim of identifying the pathogen causing serious reproductive problems on a commercial sheep farm. Sera from all rams and ewes tested negative for antibodies against Border disease virus, Schmallenberg virus and Coxiella burnetii, and infections by these agents were therefore ruled out. Nevertheless, seropositivity to N. caninum and/or Toxoplasma gondii was detected, although the seroprevalence was higher in the case of N. caninum. The percentage of lambings and the number of lambs per dam were significantly lower in ewes that were seropositive to N. caninum while no effect on these parameters was detected in ewes that were seropositive to T. gondii. There was also no evidence of infection by T. gondii in the foetal/lamb tissues analyzed by PCR and/or immunohistopathological techniques. On the contrary, the DNA of N. caninum was detected in 13 out of 14 foetuses/lambs descendant from dams seropositive to this parasite. Characteristic lesions caused by N. caninum and/or its antigen were also detected. Genotyping of the N. caninum DNA revealed only two closely related microsatellite multilocus genotypes. The results clearly demonstrate that infection by N. caninum was the cause of the low reproductive performance of this sheep flock.
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18
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Experimental ruminant models for bovine neosporosis: what is known and what is needed. Parasitology 2014; 141:1471-88. [PMID: 24926962 DOI: 10.1017/s0031182014000638] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
At present, bovine neosporosis is an important worldwide concern because of its wide geographic distribution and economic impact. Abortion is the main clinical sign of bovine neosporosis in both dairy and beef cattle. Ruminant challenge models are critical to evaluate potential vaccine candidates to help tackle bovine neosporosis and to study pathogenesis and host responses to infection. Several research groups have developed ruminant models of Neospora caninum infection independently of others, resulting in a high degree of variability due to the use of different species of animals, breeds, strains/isolates of N. caninum, doses, routes and times of inoculation. Standardization is greatly needed to advance research in a more collaborative, timely and efficient manner. In the absence of widely accepted international guidelines, this manuscript serves to summarize and discuss the different models and parameters currently in use. Parameters essential for the development of non-pregnant and pregnant ruminant models are outlined and the main knowledge gaps are identified. This information could act as the basis to develop a consensus for international standard guidelines for ruminant models of neosporosis that would be helpful for researchers in this field worldwide.
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19
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Monney T, Hemphill A. Vaccines against neosporosis: what can we learn from the past studies? Exp Parasitol 2014; 140:52-70. [PMID: 24602874 DOI: 10.1016/j.exppara.2014.02.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 02/09/2014] [Accepted: 02/18/2014] [Indexed: 10/25/2022]
Abstract
Neospora caninum is an intracellular apicomplexan parasite, which is a leading cause of abortion in cattle; thus neosporosis represents an important veterinary health problem and is of high economic significance. The parasite can infect cattle via trans-placental transmission from an infected cow to its fetus (vertical transmission), or through the oral route via ingestion of food or water contaminated with oocysts that were previously shed with the feces of a canid definitive host (horizontal transmission). Although vaccination was considered a rational strategy to prevent bovine neosporosis, the only commercialized vaccine (Neoguard®) produced ambiguous results with relatively low efficacy, and was recently removed from the market. Therefore, there is a need to develop an efficient vaccine capable of preventing both, the horizontal transmission through infected food or water to a naïve animal as well as the vertical transmission from infected but clinically asymptomatic dams to the fetus. Different vaccine strategies have been investigated, including the use of live attenuated vaccines, killed parasite lysates, total antigens or antigen fractions from killed parasites, and subunit vaccines. The vast majority of experimental studies were performed in mice, and to a certain extent in gerbils, but there is also a large number of investigations that were conducted in cattle and sheep. However, it is difficult to directly compare these studies due to the high variability of the parameters employed. In this review, we will summarize the recent advances made in vaccine development against N. caninum in cattle and in mice and highlight the most important factors, which are likely to influence the degree of protection mediated by vaccination.
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Affiliation(s)
- Thierry Monney
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland
| | - Andrew Hemphill
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland.
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20
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Syed-Hussain SS, Howe L, Pomroy WE, West DM, Smith SL, Williamson NB. Adaptation of a commercial ELISA to determine the IgG avidity in sheep experimentally and naturally infected with Neospora caninum. Vet Parasitol 2014; 203:21-8. [PMID: 24582279 DOI: 10.1016/j.vetpar.2014.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 01/07/2014] [Accepted: 01/07/2014] [Indexed: 10/25/2022]
Abstract
Recent reports indicate Neospora caninum has a possible role in causing abortions in sheep in New Zealand. Knowledge about the epidemiology of neosporosis in sheep is limited. This study aimed to adapt and validate a commercially available ELISA assay as an IgG avidity assay to discriminate between acute (primary and re-inoculated) and chronic N. caninum infections in sheep. In addition, it was used to compare the antibody avidity values between lambs from ewes inoculated with N. caninum either during the pregnancy or in the previous year. The avidity assay was undertaken by using 6M urea for the first wash after incubation with the primary antibody in the commercial ELISA (Chekit* Neospora antibody test kit, IDEXX Laboratories, Australia). Sequential serum samples were obtained from naïve ewes (n=16) experimentally inoculated with live N. caninum tachyzoites. All ewes were seropositive by two weeks post-inoculation and remained seropositive for 20 weeks post-inoculation. There was a linear relationship between time after inoculation and avidity values (p<0.05) over the first 24 weeks. In Week 4, all animals had avidity values <35% and by Week 8, 8/16 animals had avidity values of >35%. These results suggest that an avidity value of <35% indicates a recent primary infection while a value of >35% is indicative of a chronic infection. The assay was then validated using samples from other groups of experimentally inoculated sheep as well as samples from naturally infected ewes. When comparing sample to positive ratio (S/P) and avidity values from lambs born from recently inoculated ewes with those from ewes inoculated the previous year and re-inoculated in the current year, it was possible to differentiate the lambs at 2 weeks of age. Lambs from recently inoculated ewes had low S/P and avidity values at 2 weeks of age which increased by 12 weeks of age. In comparison, lambs from re-inoculated ewes had high S/P and avidity values at 2 weeks of age, due to maternal antibody influence but values were similar to those from lambs that were born from recently inoculated ewes at 12 weeks of age. Avidity values for four naturally infected ewes were all >60% indicating chronic infection. These results suggest that the assay is able to discriminate between recent and chronic infection in sheep as well as able to differentiate lambs with maternal immunity compared to their own de novo immunity. As such it can be utilized to understand the kinetics of N. caninum infection in sheep.
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Affiliation(s)
- S S Syed-Hussain
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - L Howe
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - W E Pomroy
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand.
| | - D M West
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - S L Smith
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
| | - N B Williamson
- Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North 4412, New Zealand
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21
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Dong J, Otsuki T, Kato T, Kohsaka T, Ike K, Park EY. Development of two murine antibodies against Neospora caninum using phage display technology and application on the detection of N. caninum. PLoS One 2013; 8:e53264. [PMID: 23308179 PMCID: PMC3540087 DOI: 10.1371/journal.pone.0053264] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 11/27/2012] [Indexed: 12/03/2022] Open
Abstract
Neosporosis, caused by an intracellular parasite, Neospora caninum, is an infectious disease primarily of cattle and dogs. It occurs worldwide and causes huge damages to dairy farms. In this study, we immunized mice with recombinant surface-associated protein 1 of N. caninum (rNcSAG1) and developed two novel monoclonal antibodies, A10 and H3, against NcSAG1 using phage-display technology. Both clones bound to purified rNcSAG1 and the half maximal inhibitory concentrations of A10 and H3 are 50 and 72 nM of rNcSAG1, respectively. In immunofluorescence assays, both A10 and H3 Fabs bound to N. caninum parasites. Direct detection of N. caninum parasites was developed firstly using an enzyme-linked immunosorbent assay (ELISA) with A10 and H3. Binding of A10 and H3 antibodies to rNcSAG1 was also inhibited by some certain anti-N. caninum antibodies in the neosporosis-positive cattle sera, suggesting they might bind to the same epitopes of NcSAG1 with those anti-N. caninum antibodies of bovine. These antibodies were demonstrated to have a potential for monitoring the N. caninum parasites in a dairy farm, which may lead to protect livestock from parasite-infection.
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Affiliation(s)
- Jinhua Dong
- Laboratory of Biotechnology, Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Takahiro Otsuki
- Laboratory of Biotechnology, Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Tatsuya Kato
- Laboratory of Biotechnology, Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Tetsuya Kohsaka
- Laboratory of Animal Reproduction & Physiology, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Kazunori Ike
- Laboratory of Veterinary Parasitology, Nippon Veterinary and Life University, Musashino, Tokyo, Japan
| | - Enoch Y. Park
- Laboratory of Biotechnology, Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan
- Laboratory of Biotechnology, Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- * E-mail:
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Sasani F, Javanbakht J, Seifori P, Fathi S, Hassan MA. Neospora caninum as causative agent of ovine encephalitis in Iran. ACTA ACUST UNITED AC 2013. [DOI: 10.7243/2052-7896-1-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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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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Dong J, Otsuki T, Kato T, Park EY. Development of a diagnostic method for neosporosis in cattle using recombinant Neospora caninum proteins. BMC Biotechnol 2012; 12:19. [PMID: 22558916 PMCID: PMC3441611 DOI: 10.1186/1472-6750-12-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 03/29/2012] [Indexed: 05/05/2023] Open
Abstract
Background Neosporosis is an infectious disease primarily of cattle and dogs, caused by intracellular parasite, Neospora caninum. Neosporosis appears to be a major cause of abortion in dairy cattle worldwide and causes to huge economic loss to dairy industry. Results Recombinant surface associated antigen 1 (NcSAG1), NcSAG1 related sequence 2 (NcSRS2) and the dense granule antigen 2 (NcGRA2) of N. caninum were expressed either in silkworm or in Escherichia coli and purified. The purified recombinant proteins bound to the N. caninum-specific antibodies in serum samples from infected cattle as revealed by an enzyme-linked immunosorbent assay (ELISA). By co-immobilizing these recombinant proteins, a novel indirect ELISA was developed for detection of neosporosis. With the use of 32 serum samples, comprising 12 positive serum samples and 20 negative serum samples, the sensitivity and specificity of the assay were found to be 91.7 and 100%, respectively. Seventy-two serum samples from dairy farms were also tested and one was diagnosed with neosporasis with both this method and a commercial assay. Conclusions A diagnostic method employing recombinant proteins of N. caninum was developed. The method showed high sensitivity and specificity. Diagnostic test with field serum samples suggested its applicability to the practical diagnosis of neosporosis.
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Affiliation(s)
- Jinhua Dong
- Laboratory of Biotechnology, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
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25
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Bartley PM, Wright SE, Maley SW, Macaldowie CN, Nath M, Hamilton CM, Katzer F, Buxton D, Innes EA. Maternal and foetal immune responses of cattle following an experimental challenge with Neospora caninum at day 70 of gestation. Vet Res 2012; 43:38. [PMID: 22536795 PMCID: PMC3416710 DOI: 10.1186/1297-9716-43-38] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/26/2012] [Indexed: 02/06/2023] Open
Abstract
The immune responses of pregnant cattle and their foetuses were examined following inoculation on day 70 of gestation either intravenously (iv) (group 1) or subcutaneously (sc) (group 2) with live NC1 strain tachyzoites or with Vero cells (control) (group 3). Peripheral blood mononuclear cell (PBMC) responses to Neospora antigen and foetal viability were assessed throughout the experiment. Two animals from each group were sacrificed at 14, 28, 42 and 56 days post inoculation (pi). At post mortem, maternal lymph nodes, spleen and PBMC and when possible foetal spleen, thymus and PBMC samples were collected for analysis. Inoculation with NC1 (iv and sc) lead to foetal deaths in all group 1 dams (6/6) and in 3/6 group 2 dams from day 28pi; statistically significant (p ≤ 0.05) increases in cell-mediated immune (CMI) responses including antigen-specific cell proliferation and IFN-γ production as well as increased levels of IL-4, IL-10 and IL-12 were observed in challenged dams compared to the group 3 animals. Lymph node samples from the group 2 animals carrying live foetuses showed greater levels of cellular proliferation as well as significantly (p ≤ 0.05) higher levels of IFN-γ compared to the dams in group 2 carrying dead foetuses. Foetal spleen, thymus and PBMC samples demonstrated cellular proliferation as well as IFN-γ, IL-4, IL-10 and IL-12 production following mitogenic stimulation with Con A from day 14pi (day 84 gestation) onwards. This study shows that the generation of robust peripheral and local maternal CMI responses (lymphoproliferation, IFN-γ) may inhibit the vertical transmission of the parasite.
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Affiliation(s)
- Paul M Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, Scotland, United Kingdom.
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Potential involvement of Neospora caninum in naturally occurring ovine abortions in New Zealand. Vet Parasitol 2011; 185:64-71. [PMID: 22112976 DOI: 10.1016/j.vetpar.2011.10.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 10/17/2011] [Accepted: 10/24/2011] [Indexed: 11/21/2022]
Abstract
Neospora caninum is an obligate intracellular parasite and is recognised as the leading cause of bovine abortion worldwide. Natural infection with N. caninum has been described in sheep but it has generally not been regarded as a significant cause of abortion. Recently, there have been several New Zealand cases of foetal abortions where N. caninum was detected which strongly suggested the involvement of Neospora in these abortions. However, there is minimal information about the prevalence of N. caninum infection naturally occurring in New Zealand sheep flocks and particularly its impact on reproduction success. Thus, this present study provides preliminary data on the role that Neospora is playing in ovine reproductive failure by establishing the prevalence of N. caninum antibodies and DNA in ewe blood and foetal material present in 21 New Zealand sheep farms with ongoing unexplained abortion problems and 10 farms with consistently high fertility levels. The results of this study demonstrated an overall seroprevalence of 1.4% which varied between Aborting/non-pregnant (1.8%), age-matched pregnant controls (0.6%) and high fertility (2.1%) ewes. However, despite the variation observed, there was no statistical difference between the three groups. In addition, Neospora DNA was detected by PCR in 13% of submitted foetal brains and in ewe blood from aborting/non-pregnant (6.9%), age-matched pregnant controls (3.6%) and high fertility pregnant (2.1%) ewes. When the PCR results were considered with the IFAT and IDEXX ELISA results, there was no correlation between serology positive and PCR positive blood samples. Taken together, these results reveal that reliance on ELISA-based serology or PCR alone may underestimate the involvement of Neospora. Furthermore, determining the involvement of Neospora appears to require a multi-facetted approach where diagnostic methods and serological cut-off values may need to be adjusted as further information about the effect of natural infections with N. caninum in the ovine host is elucidated.
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Wilkowsky SE, Bareiro GG, Mon ML, Moore DP, Caspe G, Campero C, Fort M, Romano MI. An applied printing immunoassay with recombinant Nc-SAG1 for detection of antibodies to Neospora caninum in cattle. J Vet Diagn Invest 2011; 23:971-6. [DOI: 10.1177/1040638711416845] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Neospora caninum is a protozoan parasite that causes an important reproductive disease in cattle. Neospora caninum surface antigen 1 (Nc-SAG1) is an immunodominant candidate for the development of a diagnostic reagent for neosporosis. The current study describes the development and evaluation of an antigen print immunoassay (APIA) with recombinant Nc-SAG1 for the detection of specific antibodies to N. caninum in cattle. The concordance between APIA and a commercial enzyme-linked immunosorbent assay (ELISA) was evaluated with 232 serum samples from experimentally and naturally infected cattle. Sixty-one (26.7%) samples were positive for antibodies to N. caninum by ELISA and 58 (25.4%) by APIA. The new assay had a sensitivity of 85% and a specificity of 96%. These results, along with the potential of APIA to evolve into a multiple antigen detection format, suggest that this method would be a reliable diagnostic test for detection of antibodies to N. caninum in cattle.
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Affiliation(s)
- Silvina Elizabeth Wilkowsky
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - Guillermo Gimenez Bareiro
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - María Laura Mon
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - Dadin Prando Moore
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - Gastón Caspe
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - Carlos Campero
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - Marcelo Fort
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
| | - María Isabel Romano
- Biotechnology Institute, Veterinary and Agronomic Sciences Research Center (CICVyA)
- National Institute of Agricultural Technology (INTA)
- Castelar, Buenos Aires, Argentina (Wilkowsky, Mon, Romano)
- Faculty of Veterinary Science, Universidad Nacional de Asunción, Paraguay (Gimenez Bareiro)
- Agricultural Experimental Station (EEA)
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Machado GP, Kikuti M, Langoni H, Paes AC. Seroprevalence and risk factors associated with neosporosis in sheep and dogs from farms. Vet Parasitol 2011; 182:356-8. [PMID: 21676548 DOI: 10.1016/j.vetpar.2011.05.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 05/16/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
Abstract
This study aimed to establish the seroprevalence and risk factors associated with neosporosis in sheep and dogs from rural properties. 1497 blood samples were collected from sheep and 42 from dogs that cohabited with sheep from 16 farms located in the central region of São Paulo State, Brazil. For the detection of N. caninum antibodies it was performed the indirect fluorescent antibody test (IFAT ≥ 25). For the epidemiological study it was applied a questionnaire for the owners or responsible from the sheep and dogs regarding informations related to neosporosis. The seroprevalence obtained out of the 1497 sheep sera tested was 8.0% (CI95%=6.7-9.2%) and out of the 42 dogs 4.8% (CI95%=0-7.2%). Variables statistically related to seropositivity for N. caninum in sheep were: dams well as water supply (P=0.0004; OR=2.15), presence of other domestic canids (P=0.0013; OR=2.38) and presence of reproductive problems (P=0.0031; OR=1.75).
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Affiliation(s)
- Gustavo Puglia Machado
- Department of Veterinary Hygiene and Public Health, School of Veterinary Medicine and Animal Science, São Paulo State University, 18618-000 Botucatu, SP, Brazil.
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29
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Langoni H, Greca H, Guimarães FF, Ullmann LS, Gaio FC, Uehara RS, Rosa EP, Amorim RM, Da Silva RC. Serological profile of Toxoplasma gondii and Neospora caninum infection in commercial sheep from São Paulo State, Brazil. Vet Parasitol 2011; 177:50-4. [DOI: 10.1016/j.vetpar.2010.11.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 11/08/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022]
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30
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Development of lesions and tissue distribution of parasite in lambs orally infected with sporulated oocysts of Toxoplasma gondii. Vet Parasitol 2011; 179:209-15. [PMID: 21440372 DOI: 10.1016/j.vetpar.2011.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/22/2011] [Accepted: 03/02/2011] [Indexed: 01/12/2023]
Abstract
The host-pathogen interaction is as a key feature during the formation of tissue cysts of Toxoplasma gondii within intermediate hosts. In this study, we investigated whether oral infection of lambs with T. gondii oocysts may be used as an experimental model in sheep to study this interaction, with the main objective being to detect the presence and distribution of lesions and parasite within different organs at different time points after oral infection. Lambs were infected with 5 × 10(3) and 5 × 10(5) sporulated T. gondii oocysts and culled at 2, 3, 5 and 6 weeks post-infection (WPI). During the infection, rectal temperature of the animals and serological antibodies against T. gondii were monitored. The presence of inflammatory lesions and parasite were evaluated through histological and immunohistochemical methods at different organs (brain, liver, lung, heart and lymph nodes). The lambs showed no clinical signs other than fever, and lesions appeared mainly in the brain, characterized by glial foci and perivascular cuffs, and in the heart, denoted by foci of interstitial myositis. Tissue cysts and tachyzoite-like structures were observed at all time points studied in the brain, where together with the glial foci they appeared mainly in the cerebral cortex of the forebrain and in the midbrain, but also in the heart, lung and lymph nodes. This study shows that oral infection with sporulated oocysts in lambs may provide a model for investigating the host-parasite interaction in situ during the development of tissue cysts.
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Bishop S, King J, Windsor P, Reichel MP, Ellis J, Slapeta J. The first report of ovine cerebral neosporosis and evaluation of Neospora caninum prevalence in sheep in New South Wales. Vet Parasitol 2010; 170:137-42. [PMID: 20189309 DOI: 10.1016/j.vetpar.2010.01.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 01/15/2010] [Accepted: 01/20/2010] [Indexed: 11/27/2022]
Abstract
Presence of Neospora caninum DNA was detected in the brain and spinal cord of an adult Merino sheep suspected of dying with acute non-suppurative meningoencephalitis and mild to moderate non-suppurative myelitis. The most severe neurological lesions were found in the midbrain at the rostral coliculi with moderate to severe multifocal vasculitis and gliosis. As this was the first known occurrence of cerebral disease in sheep in Australia caused by N. caninum, we surveyed sera from five sheep properties in New South Wales (NSW) to obtain information on the likely prevalence of N. caninum infection in NSW sheep flocks. Serology using a commercial indirect enzyme-linked immunosorbent assay (ELISA) revealed no N. caninum antibody-positive sheep (n=184). However an observed prevalence for N. caninum antibodies using a commercially available competitive ELISA was 2.2% (5/232). We conclude that although the diagnosis of fatal ovine cerebral neosporosis is of importance to our surveillance program for transmissible spongiform encephalopathy (TSE) exclusion, sheep in NSW are not commonly infected with N. caninum and this species likely plays only a minor role in the life cycle of this parasite in Australia.
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Affiliation(s)
- Stephanie Bishop
- Faculty of Veterinary Science, University of Sydney, New South Wales 2006, Australia
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Weston J, Howe L, Collett M, Pattison R, Williamson N, West D, Pomroy W, Syed-Hussain S, Morris S, Kenyon P. Dose-titration challenge of young pregnant sheep with Neospora caninum tachyzoites. Vet Parasitol 2009; 164:183-91. [DOI: 10.1016/j.vetpar.2009.05.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 05/04/2009] [Accepted: 05/11/2009] [Indexed: 11/25/2022]
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34
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Soares HS, Ahid SM, Bezerra AC, Pena HF, Dias RA, Gennari SM. Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Mossoró, Rio Grande do Norte, Brazil. Vet Parasitol 2009; 160:211-4. [DOI: 10.1016/j.vetpar.2008.10.102] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 10/31/2008] [Accepted: 10/31/2008] [Indexed: 10/21/2022]
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35
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Modolo JR, Stachissini AV, Gennari SM, Dubey JP, Langoni H, Padovani CR, Barrozo LV, Leite BL. Freqüência de anticorpos anti-Neospora caninum em soros de caprinos do estado de São Paulo e sua relação com o manejo dos animais. PESQUISA VETERINARIA BRASILEIRA 2008. [DOI: 10.1590/s0100-736x2008001200006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Com o objetivo de se avaliar a freqüência de caprinos leiteiros soropositivos para Neospora caninum, no estado de São Paulo, e se verificarem possíveis associações com idade, sexo e problemas reprodutivos, nos capris, e, também, presença de cães, nas propriedades, foram obtidos soros de 923 caprinos de ambos os sexos e idade acima de 3 meses. Os animais eram provenientes de 17 propriedades de diferentes municípios. Para o diagnóstico, foi utilizado o teste de aglutinação para Neospora (NATe"25), e, em todos os capris, aplicou-se um inquérito a partir do qual se obtiveram informações epidemiológicas e de esfera reprodutiva. Todos os resultados estatísticos foram discutidos no nível de 5% de significância. Assim, chegou-se à conclusão de que a freqüência percentual de positividade para N. caninum foi de 19,77%, e, em apenas uma propriedade, não houve registro de animal soropositivo, o que revela difusão do agente, no Estado. Não foram verificadas diferenças significativas entre freqüências de positividade quanto ao sexo, idade ou problemas reprodutivos. Porém, ressalta-se que a presença de cães, nos capris, foi associada a uma maior freqüência de caprinos soropositivos a N. caninum. A representação geográfica da distribuição de caprinos soropositivos para o protozoário, em mapa coroplético em hachuras, pode implicar em um ganho considerável para estudos da epidemiologia geográfica, na elaboração de um planejamento de controle da enfermidade.
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36
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Ueno TEH, Gonçalves VSP, Heinemann MB, Dilli TLB, Akimoto BM, de Souza SLP, Gennari SM, Soares RM. Prevalence of Toxoplasma gondii and Neospora caninum infections in sheep from Federal District, central region of Brazil. Trop Anim Health Prod 2008; 41:547-52. [DOI: 10.1007/s11250-008-9220-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 08/07/2008] [Indexed: 11/29/2022]
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37
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Howe L, West D, Collett M, Tattersfield G, Pattison R, Pomroy W, Kenyon P, Morris S, Williamson N. The role of Neospora caninum in three cases of unexplained ewe abortions in the southern North Island of New Zealand. Small Rumin Res 2008. [DOI: 10.1016/j.smallrumres.2007.08.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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38
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Buxton D, Maley SW, Wright SE, Rodger S, Bartley P, Innes EA. Toxoplasma gondii and ovine toxoplasmosis: New aspects of an old story. Vet Parasitol 2007; 149:25-8. [PMID: 17686585 DOI: 10.1016/j.vetpar.2007.07.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ovine toxoplasmosis, caused by the intracellular protozoan parasite Toxoplasma gondii, was first described in 1954 and while the incidence of ovine infection is difficult to define, it has been reported that in the UK it is responsible for between 1 and 2% of neonatal losses per annum. Recent reports have suggested that sheep persistently infected with T. gondii may pass infection to the fetus in subsequent pregnancies more readily than previously thought. These data show a high proportion of both successful and failed pregnancies in sheep to be positive by PCR for T. gondii with a tendency for samples from certain genetic lines of Charollais sheep more likely to be positive than samples from other lines, suggesting that some sheep have a particular genetic susceptibility to T. gondii.
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Affiliation(s)
- David Buxton
- Moredun Research Institute, Edinburgh, Scotland, United Kingdom.
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39
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Bartley PM, Wright S, Chianini F, Buxton D, Innes EA. Inoculation of Balb/c mice with live attenuated tachyzoites protects against a lethal challenge of Neospora caninum. Parasitology 2007; 135:13-21. [PMID: 17767798 DOI: 10.1017/s0031182007003526] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neospora caninum tachyzoites attenuated through passage in tissue culture were tested for their ability to induce protective immunity against a lethal challenge dose of parasites. Balb/c mice were each inoculated with either 1x10(6) live virulent tachyzoites (Group 1) or 1x10(6) live attenuated tachyzoites (Group 2), while (Group 3) received a control inoculum. All mice were each challenged 28 days later with 5x10(6) virulent parasites. Histopathological lesions in the brains including necrosis and microgliosis were observed following post-mortem on day 28 post-challenge (p.c.) in 71% of Group 1 and 56% of Group 2. Immunohistochemistry (IHC) of these lesions showed tachyzoites and Neospora antigens to be associated with moderate brain lesions in 17% of Group 1, while in 11% of Group 2 N. caninum tissue cysts were detected, but these were not associated with lesions, Parasite DNA was detected by PCR in the brains of 86% of mice in Group 1 and 56% of mice in Group 2. Following challenge the mice in Group 3 showed high morbidity and 100% mortality within 17 days p.c. Positive IHC for N. caninum was seen in 88% of the Group 3 mice and parasite DNA was detected in all brain samples. This study shows that it is possible to protect against a lethal challenge of N. caninum through inoculation with attenuated or virulent tachyzoites. However, more severe pathology developed in mice initially inoculated with virulent parasites following a secondary challenge, compared to mice initially inoculated with attenuated parasites.
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Affiliation(s)
- P M Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, Scotland, UK.
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40
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Innes EA, Bartley PM, Maley SW, Wright SE, Buxton D. Comparative host–parasite relationships in ovine toxoplasmosis and bovine neosporosis and strategies for vaccination. Vaccine 2007; 25:5495-503. [PMID: 17367899 DOI: 10.1016/j.vaccine.2007.02.044] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 01/24/2007] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
Toxoplasma gondii and Neospora caninum are important causes of reproductive loss in ruminant species worldwide. Both parasites cause disease during pregnancy that may result in foetal death or birth of live congenitally infected offspring. T. gondii is also an important human pathogen with the main risk groups including pregnant women and immuno-compromised individuals, although clinical disease has also been observed in outbreaks among immuno-competent people. While the two parasites are closely related there are distinct differences between the two in their interactions with different host species and subsequent clinical outcome. This paper discusses the respective host-parasite relationships in ovine toxoplasmosis and bovine neosporosis and how the immune response may be host-protective, parasite-protective or contribute to disease pathogenesis, and how this knowledge may help in the development of more effective and targeted vaccination strategies.
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Affiliation(s)
- Elisabeth A Innes
- Moredun Research Institute, Pentlands Science Park, Edinburgh EH26 OPZ, United Kingdom.
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41
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Bartley PM, Wright S, Sales J, Chianini F, Buxton D, Innes EA. Long-term passage of tachyzoites in tissue culture can attenuate virulence of Neospora caninum in vivo. Parasitology 2006; 133:421-32. [PMID: 16762097 DOI: 10.1017/s0031182006000539] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Revised: 04/19/2006] [Accepted: 04/20/2006] [Indexed: 11/07/2022]
Abstract
To determine whether prolonged in vitro passage would result in attenuation of virulence in vivo, Neospora caninum tachyzoites were passaged for different lengths of time in vitro and compared for their ability to cause disease in mice. Groups of Balb/c mice were inoculated intraperitoneally with 5×106 or 1×107 of low-passage or high-passage N. caninum tachyzoites. The mice were monitored for changes in their demeanour and body weight, and were culled when severe clinical symptoms of murine neosporosis were observed. Mice inoculated with the high-passage parasites survived longer (P<0·05), and showed fewer clinical symptoms of murine neosporosis, compared to the mice receiving the low-passage parasites. The parasite was detected in the brains of inoculated mice using immunohistochemistry and ITS1 PCR. Tissue cysts containing parasites were seen in mice inoculated with both low-passage and high-passage parasites. When the in vitro growth rates of the parasites were compared, the high-passage parasites initially multiplied more rapidly (P<0·001) than the low-passage parasites, suggesting that the high-passage parasites had become more adapted to tissue culture. These results would suggest that it is possible to attenuate the virulence of N. caninum tachyzoites in mice through prolonged in vitro passage.
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Affiliation(s)
- P M Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, Scotland, UK.
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42
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West D, Pomroy W, Collett M, Hill F, Ridler A, Kenyon P, Morris S, Pattison R. A possible role for Neospora caninum in ovine abortion in New Zealand. Small Rumin Res 2006. [DOI: 10.1016/j.smallrumres.2005.07.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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43
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Macaldowie C, Maley SW, Wright S, Bartley P, Esteban-Redondo I, Buxton D, Innes EA. Placental pathology associated with fetal death in cattle inoculated with Neospora caninum by two different routes in early pregnancy. J Comp Pathol 2005; 131:142-56. [PMID: 15276854 DOI: 10.1016/j.jcpa.2004.02.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2003] [Accepted: 02/23/2004] [Indexed: 11/19/2022]
Abstract
Pregnant cattle were inoculated with N. caninum strain NC-1 tachyzoites intravenously (iv) (group 1, n = 8) or subcutaneously (sc) (group 2, n = 8) at 70 days' gestation. Control animals (group 3; n = 8) received uninfected Vero cells iv. Two animals from each group were killed at 14, 28, 42 and 56 days post-inoculation (dpi). Fetal mortality was 100% and 50%, respectively, in groups 1 and 2 from 28 dpi. In group 1 foci of degenerative fetal placental villi were observed at 14 dpi, with clusters of N. caninum tachyzoites in the affected mesenchyme. There was also inflammation of maternal septal tissues, with necrotic cell debris and serum exudate at the interstitium. At 28 dpi pregnancy had ended and the fetal cotyledons had become detached from the maternal caruncles. Immunohistochemically, particulate N. caninum antigen was detected in the cotyledons. At 42 and 56 dpi, fetal tissues had disappeared, the caruncles were greatly reduced in size, and the uterine epithelium had been largely restored. In group 2, lesions were either severe or absent ("all or nothing" response). In one animal carrying a dead fetus at 28 dpi, placentitis was much more severe than that seen in group 1 at 14 dpi. Lesions contained neutrophils, eosinophils and N. caninum antigen. In animals carrying dead fetuses at 42 and 56 dpi, fetal remains were found and the cotyledons contained N. caninum antigen. Antigen was also detected in fetal tissues. No significant pathological changes were detected in group 2 animals carrying live fetuses or any animal in group 3. Thus, N. caninum administered iv or sc in early pregnancy resulted in rapid fetal death, with parasite-associated lesions in the placenta and fetus. Of the two inoculation routes, the intravenous induced the more acute placental lesions and greater mortality.
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Affiliation(s)
- C Macaldowie
- Division of Virology, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 OPZ, UK
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van Maanen C, Wouda W, Schares G, von Blumröder D, Conraths FJ, Norton R, Williams DJL, Esteban-Redondo I, Innes EA, Mattsson JG, Björkman C, Fernández-García A, Ortega-Mora LM, Müller N, Sager H, Hemphill A. An interlaboratory comparison of immunohistochemistry and PCR methods for detection of Neospora caninum in bovine foetal tissues. Vet Parasitol 2004; 126:351-64. [PMID: 15567040 DOI: 10.1016/j.vetpar.2004.08.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 08/09/2004] [Accepted: 08/17/2004] [Indexed: 11/24/2022]
Abstract
Seven European laboratories contributed to a multi-centre evaluation of detection techniques for Neospora caninum in bovine foetuses. Six laboratories participated in immunohistochemistry (IHC) testing. All seven laboratories participated in PCR testing, but the results from one laboratory were not included in the analysis, because of contamination problems in the preparation of the samples. A coded panel of tissue sections from 36 infected and non-infected foetuses was used to evaluate the IHC detection of parasites. A coded panel consisting of 44 homogenized foetal brain samples from natural bovine abortion cases and 32 spiked samples were used to evaluate the PCR methods. Inclusion of a duplicate dilution series of spiked samples was used to evaluate detection limits and repeatability. IHC methods had a relatively low sensitivity, but a high specificity. There was considerable variation in IHC results between participating laboratories, which may be partly explained by examination practices that depended on the experience of the operator. In addition, the use of different antibody reagents, different antibody dilutions, and different enzymatic treatments of tissues may have contributed to the observed variation. PCR methods generally had a higher sensitivity than IHC methods and also a high specificity. The agreement between the majority scores of IHC and PCR methods was low. False positive PCR results indicated contamination problems in some instances. Agreement between the PCR results of the various laboratories was better, compared with the IHC results. There appeared to be no clear relationship between the PCR format (i.e. single or nested) and diagnostic sensitivity. Consequently, an improvement of diagnostic performance of PCR might possibly be achieved by optimizing DNA extraction methods.
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Affiliation(s)
- C van Maanen
- Animal Health Service, P.O. Box 9, NL-7400 AA Deventer, The Netherlands
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45
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Bartley PM, Kirvar E, Wright S, Swales C, Esteban-Redondo I, Buxton D, Maley SW, Schock A, Rae AG, Hamilton C, Innes EA. Maternal and fetal immune responses of cattle inoculated with Neospora caninum at mid-gestation. J Comp Pathol 2004; 130:81-91. [PMID: 15003463 DOI: 10.1016/j.jcpa.2003.08.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2003] [Accepted: 08/23/2003] [Indexed: 11/30/2022]
Abstract
The humoral and cell-mediated immune responses of pregnant cattle and their fetuses were examined at intervals after infection with Neospora caninum tachyzoites at mid-gestation (day 140). All cattle seroconverted and interferon gamma was detected in supernatants of peripheral blood mononuclear cells stimulated with specific antigen. At day 14 post-inoculation (pi), specific cell proliferation responses were detected in the lymph node draining the site of inoculation and in the uterine lymph node. The peak response was recorded in the majority of maternal lymph nodes by day 28 pi and cells from the maternal retropharyngeal lymph node, which in part drains the central nervous system, showed no specific activity to N. caninum until day 42 pi. This changing pattern of immune responsiveness may reflect parasite invasion and development within different host tissues. Fetal lymph node cells showed mitogen responsiveness from day 14 pi (day 154 of gestation) and also showed N. caninum-specific cell proliferation and interferon-gamma responses by day 28 pi (day 168 of gestation). At day 42 pi, specific cell-mediated immune responses were not apparent; however, N. caninum-specific fetal IgG and IgM antibodies were detected.
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Affiliation(s)
- P M Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Edinburgh, Scotland EH26 0PZ, UK
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46
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Jenkins MC, Tuo W, Dubey JP. Evaluation of vaccination with Neospora caninum protein for prevention of fetal loss associated with experimentally induced neosporosis in sheep. Am J Vet Res 2004; 65:1404-8. [PMID: 15524328 DOI: 10.2460/ajvr.2004.65.1404] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the immunologic response of a killed tachyzoite vaccine against Neospora caninum and its effectiveness in preventing fetal loss associated with experimentally induced neosporosis in sheep. ANIMALS 30 Dorset ewes. PROCEDURE Ewes were randomly allocated to receive vaccination on days 1 and 60 of the study with a killed N caninum tachyzoite preparation in a commercially available adjuvant or a saline-adjuvant mixture. A ram was placed on pasture with the ewes from days 15 to 60. Blood was collected from ewes before primary and booster vaccinations and prior to experimental challenge with N caninum tachyzoite performed on day 90; sera were assessed via Neospora agglutination (NA) and immunofluorescence antibody (IFA) assays. Blood was collected from lambs before they suckled, and sera were tested for antibodies against N caninum. RESULTS Of the 14 vaccinated ewes that became pregnant, 12 gave birth to live-born lambs; in contrast, 5 of 11 pregnant control ewes gave birth to live-born lambs. Whereas vaccination improved fetal survival in pregnant ewes challenged with N caninum tachyzoites, it did not appear to have any appreciable effect on transmission of N caninum to offspring, as indicated by results of NA and IFA assays. CONCLUSIONS AND CLINICAL RELEVANCE The N caninum tachyzoite vaccine used in this study appeared to provide protection against fetal loss associated with experimentally induced neosporosis in a high proportion of pregnant ewes.
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Affiliation(s)
- Mark C Jenkins
- Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA
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47
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Rettigner C, Lasri S, De Meerschman F, Focant C, Beckers JF, Losson B. Immune response and antigen recognition in non-pregnant ewes experimentally infected with Neospora caninum tachyzoites. Vet Parasitol 2004; 122:261-71. [PMID: 15262004 DOI: 10.1016/j.vetpar.2003.12.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2003] [Revised: 12/11/2003] [Accepted: 12/30/2003] [Indexed: 11/30/2022]
Abstract
The cellular and humoral responses as well as the antigen recognition during the acute stage of a Neospora caninum (NC) infection were investigated in non-pregnant ewes. The experimentally infected ewes developed specific lymphoproliferative and humoral responses within 2 weeks post-infection (PI). The magnitude of the cellular response showed large variations between animals. A significant decrease in the proliferative response to Con A mitogen and N. caninum, Toxoplasma gondii (TG) antigens was recorded on day 21 post-infection (PI). The humoral response and the pattern of antigen recognition were similar among infected ewes. Proteins of 44, 42, 40, 39 and 28 kDa were intensively recognized by the infected animals during the experiment. The 42 and 28 kDa antigens should be considered as useful for the diagnostic of N. caninum infection, as the intensity of recognition infection of the other antigens had decreased markedly 8 weeks post-infection. For some antigens a sequential recognition was recorded. The 59, 54 and 38-37 kDa proteins were frequently recognized by infected sera during the first weeks of the infection, but recognition of these antigens was absent or rare at the end of the experiment. These antigens could be related to the acute stage of the infection.
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Affiliation(s)
- Chantal Rettigner
- Department of Infectious and Parasitic Diseases, Laboratory of Parasitology and Pathology of Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Boulevard de Colonster B43a, 20, 4000 Liège, Belgium.
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48
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Abstract
In this fifth article of a series of papers listing first case reports of animal diseases published since 2000, the following five cases of sheep diseases are discussed: Ependymoma. Mastitis caused by Burkholderia cepacia infection. Meningoencephalitis associated with Globicatella sanguinis infection. Neospora caninum infection in an adult sheep and her twin fetuses. Plasma cell tumor. After a short introduction, the bibliographical data, the abstract of the author(s), and some additional information derived from the article are given. The article will be regularly updated adding overlooked as well as new first reports.
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49
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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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50
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O'Handley RM, Morgan SA, Parker C, Jenkins MC, Dubey JP. Vaccination of ewes for prevention of vertical transmission of Neospora caninum. Am J Vet Res 2003; 64:449-52. [PMID: 12693535 DOI: 10.2460/ajvr.2003.64.449] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the immunologic response of a killed tachyzoite vaccine against Neospora caninum and its effectiveness in preventing vertical transmission of N caninum in sheep. ANIMALS 40 Dorset ewes seronegative for N caninum. PROCEDURE Group-A ewes (n = 20) were vaccinated on days 1 and 126 with a killed N caninum tachyzoite preparation in a commercially available adjuvant. Group-B ewes (n = 20) were sham vaccinated. Blood samples were collected from ewes every 2 weeks and a recombinant ELISA (rELISA) was used to determine serum antibody titers against N caninum. During pregnancy, ewes were challenged with live N caninum tachyzoites. Precolostral serum was collected from lambs and tested for antibodies against N caninum by use of an indirect fluorescence antibody test and the rELISA. Tissue specimens from stillborn lambs or lambs that died within 2 weeks of birth were collected and examined for N caninum antigen and DNA by use of immunohistochemistry and polymerase chain reaction assay, respectively. RESULTS Serum antibody titers against N caninum were significantly higher in group-A ewes, compared with group B ewes, following vaccination. Serum antibodies against N caninum were detected in 100% (33/33) of group-B lambs and 75% (18/24) of group-A lambs. In tissue specimens, N caninum DNA was detected in 9 of 11 group-B lambs and 0 of 10 group-A lambs. Histologically, N caninum tachyzoites were observed in 4 group-A lambs and 3 group-B lambs. CONCLUSIONS AND CLINICAL RELEVANCE The killed tachyzoite vaccine against N caninum stimulated a humoral immune response in sheep and provided partial protection against vertical transmission.
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Affiliation(s)
- R M O'Handley
- Parasite Biology, Epidemiology and Systematics Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA
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