The Pathogenesis of Neosporosis in Pregnant Cattle: Inoculation at Mid-gestation

Maley, S.W.; Buxton, D.; Rae, A.G.; Wright, Steve; Schock, A.; Bartley, Paul M.; Esteban-Redondo, I.; Swales, C; Hamilton, C. M.; Sales, Jill; Innes, Elisabeth A.

doi:10.1016/s0021-9975(03)00032-x

Cited by 81 publications

(90 citation statements)

References 33 publications

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“…The fixed tissues were then processed by standard procedures to paraffin-wax blocks, after which slides were produced for hematoxylin and eosin staining (MALEY et al, 2003). The immunohistochemistry technique was done as previously described (MALEY et al, 2003).…”

Section: Immunohistochemistrymentioning

confidence: 99%

Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

Macedo

Miura

et al. 2017

Rev. Bras. Parasitol. Vet.

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The aim of the present study was to investigate the occurrence of N. caninum associated with abortions of dairy cattle from Santa Catarina state, southern Brazil by using enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and polymerase chain reaction (PCR). Blood from dairy cows that aborted along with intrathoracic fluid and tissue samples (brain, heart, liver, and lung) from their fetuses were collected and used for serology; PCR, histopathological, and immunohistochemistry (IHC) evaluations were also conducted. Twenty-one cows (51.2%) out of 41, and eight fetuses (26.7%) out of 30 were ELISA (HerdCheck, IDEXX) positive for N. caninum. Dams > 36 months of age had a higher risk of being serum positive than younger animals. PCR and IHC revealed that 38.8% (14/36) and 25.0% (9/36) of the fetuses were positive for N. caninum, respectively for each of the tests. Seropositive cows had a higher frequency of fetuses that were also positive by either intrathoracic fluid, PCR, or IHC. In summary, the present study observed a high frequency of N. caninum in abortions from dairy cows from southern Brazil, with a higher N. caninum prevalence found in cows that were older than 36 months. In addition, serology, PCR, and IHC should be used all together for better diagnosis of neosporosis in cattle.Keywords: Neosporosis, fetuses, lesion, serology, cattle. ResumoO objetivo deste estudo foi avaliar a ocorrência de N. caninum associado a abortamentos em vacas de leite do estado de Santa Catarina, sul do Brasil pelo uso das técnicas de ELISA (HerdCheck, IDEXX), reação em cadeia pela polimerase (PCR) e imunohistoquímica (IHC). O sangue das vacas leiteiras que abortaram, bem como, o líquido intratorácico e amostras de tecidos (cérebro, coração, fígado e pulmão) de seus fetos foram coletados e usados para sorologia, PCR (Np21+ e Np6+), e IHC. Vinte e uma vacas (51,2%) de um total de 41, bem como, oito fetos (26,7%) de um total de 30 foram positivos no ELISA (IDEXX) para N. caninum. As vacas > 36 meses de idade tiveram um maior risco de serem soropositivas do que os animais mais jovens. PCR e IHC revelaram que 38,8% e 25,0% dos fetos foram positivos para N. caninum, respectivamente para cada um dos testes. As vacas soropositivas tiveram uma maior frequência de fetos que também foram positivos no fluído intratorácico, na PCR ou na IHC. Em resumo, o presente estudo observou uma alta frequência de N. caninum em abortos de vacas leiteiras na região estudada, com maior prevalência de N. caninum em vacas com mais de 36 meses de idade. Além disso, sorologia, PCR e IHC deveriam ser utilizadas conjuntamente para melhor diagnóstico de neosporose em bovinos.

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Section: Immunohistochemistrymentioning

confidence: 99%

Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

Macedo

Miura

et al. 2017

Rev. Bras. Parasitol. Vet.

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“…Infection spreads (as tachyzoites) to other tissues in the cow, for example, neural cells, macrophages, fibroblasts, vascular endothelial cells, hepatocytes, and, if pregnant, to the placenta, where damage to the placenta or transmission vertically through the placenta to the foetus can occur. Abortion may be a result of both the primary damage and the immune-mediated inflammatory response of the cow [20]. As a result of the immune response generated, the tachyzoites can transform into bradyzoites (a slowly dividing "dormant" stage or tissue cyst).…”

Section: Transmission and Pathogenesismentioning

confidence: 99%

A Review of Some Protozoan Parasites Causing Infertility in Farm Animals

Kaltungo

Musa

2013

ISRN Tropical Medicine

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The paper reviews some protozoan parasites responsible for infertility in livestock with specific emphasis on neosporosis, sarcocystosis, toxoplasmosis, and trichomoniasis. It highlights the transmission, pathogenesis, clinical signs, diagnosis, prevention, control, and treatment of the individual parasite. It is concluded that these parasites are often overlooked during investigation into causes of abortion in livestock, and they may, however, be responsible for some infertilities in this group of animals which may result in severe economic losses.

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“…The immunologic balance that favors fetal survival also may facilitate N. caninum replication and dissemination. A type 2 cytokine bias has been associated with successful implantation and pregnancy maintenance in mammals (22), and downregulation of proinflammatory cytokines, such as IFN-␥, IL-2, and tumor necrosis factor alpha, is thought to limit potentially damaging effects of inflammation on the placenta and fetus (35). Manipulation of the immune response with subunit immunogens designed for specific gestational times (pregnant or nonpregnant), maternal 51 Cr release cytotoxicity assays.…”

Section: Mapping Ncsrs2 T-lymphocyte Epitopes By Ifn-␥ Elisa Multiplmentioning

confidence: 99%

Identification of Vaccine Candidate Peptides in the NcSRS2 Surface Protein ofNeospora caninumby Using CD4⁺Cytotoxic T Lymphocytes and Gamma Interferon-Secreting T Lymphocytes of Infected Holstein Cattle

et al. 2005

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Previously, our laboratory showed that Holstein cattle experimentally infected with Neospora caninum develop parasite-specific CD4 ؉ cytotoxic T lymphocytes (CTL) that lyse infected, autologous target cells through a perforin-granzyme pathway. To identify specific parasite antigens inducing bovine CTL and helper T-lymphocyte responses for vaccine development against bovine neosporosis, the tachyzoite major surface proteins NcSAG1 and NcSRS2 were targeted. In whole tachyzoite antigen-expanded bovine T-lymphocyte lines, recombinant NcSRS2 induced potent memory CD4؉ -and CD8 ؉ -T-lymphocyte activation, as indicated by proliferation and gamma interferon (IFN-␥) secretion, while recombinant NcSAG1 induced a minimal memory response. Subsequently, T-lymphocyte epitope-bearing peptides of NcSRS2 were mapped by using overlapping peptides covering the entire NcSRS2 sequence. Neospora caninum is an intracellular apicomplexan protozoan parasite that causes abortion and congenital infection in cattle (21). Transplacental parasite transmission is the major mode of infection (18, 45) which persists in the herd over successive generations, causing significant economic losses due to abortion, culling, and decreased milk production (13,20,25,52,53). Recrudescence of chronic, congenitally acquired infection due to downregulation of Th1 immune responses during pregnancy may be largely responsible for transplacental N. caninum transmission (10,22,27,42). A vaccine that could control tachyzoite parasitemia and decrease congenital infection or abortion rates is needed.Studies of Toxoplasma gondii, a protozoan parasite closely related to N. caninum in biology, phylogeny, and immunogenicity, unequivocally show the importance of T lymphocytes in resistance to infection by adoptive transfer, gene knockout, and depletion studies with mouse models (19). The presence of parasite-specific CD4 ϩ and CD8 ϩ cytotoxic T lymphocytes (CTL) is also associated with immunity to natural T. gondii infection in humans (14,41). In murine models of neosporosis, a T-lymphocyte-mediated immune response, characterized by increased levels of gamma interferon (IFN-␥) and interleukin 12 (IL-12), correlates with disease resistance (5,30,33), and IFN-␥ alone inhibits tachyzoite growth and cellular invasion (24,38,51,55). In pregnant mice, protection against vertical transmission correlates with induction of parasite-specific Tlymphocyte-mediated immunity (39). Cattle infected with N. caninum produce parasite-specific, major histocompatibility complex (MHC)-restricted, CD4 ϩ CTL (50) that could reduce N. caninum infection indirectly by IFN-␥ activation of mononuclear phagocytes and directly by killing N. caninum-infected cells.To identify vaccine candidate parasite antigens for induction of CTL and IFN-␥ secretion in cattle against neosporosis abortion, this study focused on major tachyzoite glycosylphosphatidylinositol-anchored surface proteins, N. caninum surface antigen 1 (NcSAG1) and N. caninum SAG1-related sequence 2 (NcSRS2) (26, 28). The T. gondii surface pr...

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The Pathogenesis of Neosporosis in Pregnant Cattle: Inoculation at Mid-gestation

Cited by 81 publications

References 33 publications

Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

A Review of Some Protozoan Parasites Causing Infertility in Farm Animals

Identification of Vaccine Candidate Peptides in the NcSRS2 Surface Protein ofNeospora caninumby Using CD4⁺Cytotoxic T Lymphocytes and Gamma Interferon-Secreting T Lymphocytes of Infected Holstein Cattle

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The Pathogenesis of Neosporosis in Pregnant Cattle: Inoculation at Mid-gestation

Cited by 81 publications

References 33 publications

Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

A Review of Some Protozoan Parasites Causing Infertility in Farm Animals

Identification of Vaccine Candidate Peptides in the NcSRS2 Surface Protein ofNeospora caninumby Using CD4+Cytotoxic T Lymphocytes and Gamma Interferon-Secreting T Lymphocytes of Infected Holstein Cattle

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Identification of Vaccine Candidate Peptides in the NcSRS2 Surface Protein ofNeospora caninumby Using CD4⁺Cytotoxic T Lymphocytes and Gamma Interferon-Secreting T Lymphocytes of Infected Holstein Cattle