Occurrences of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from four districts of Tocantins state, Brazilian Legal Amazon Region

Guimarães, Andresa; Raimundo, Juliana Macedo; Moraes, Larissa M.B.; Silva, Aline T.; Santos, Huarrisson Azevedo; Pires, Marcos S.; Machado, Rosângela Zacarias; Baldani, Cristiane Divan

doi:10.1590/s0100-736x2015000200002

Cited by 15 publications

(5 citation statements)

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“…A frequência de ovinos soropositivos a T. gondii não foi influenciado pelo sexo, como relatado por outros autores (Ogawa et al 2003, Souza Neto et al 2009, Lopes et al 2010, Guimarães et al 2015, enquanto para a neosporose, ovelhas apresentaram 9,13 vezes mais chances de estarem infectadas que carneiros, achado esse que não foi relatado em outros estudos (Figliuolo et al 2004, Romanelli et al 2007, Ueno et al 2009. As ovelhas, em geral, são mais expostas as pastagens que podem estar contaminadas com oocistos, enquanto reprodutores, características dos machos do estudo, eram criados em baias individuais ou com baixa lotação, semelhante ao sistema intensivo de criação.…”

Section: Discussionunclassified

Ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em ovinos com distúrbios reprodutivos e fatores de risco

et al. 2018

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RESUMO: Objetivou-se avaliar a ocorrência, sinais clínicos e fatores de risco associados a soropositividade para Toxoplasma gondii e Neospora caninum em ovinos. Foram utilizados 294 animais com histórico de distúrbios reprodutivos de 28 fazendas do estado de São Paulo, Brasil, diagnosticados através da imunofluorescência indireta (1:64 e 1:50). A ocorrência de T. gondii foi de 29,9% (88/294) e de N. caninum 18% (53/294), sendo 3,7% (11/294) dos ovinos soropositivos para ambos. Observou-se com maiores chances à infecção pelo T. gondii: ovinos mestiços (p=0,04), Santa Inês (p=0,006), fornecimento de pastagem (p<0,001) ou associada a concentrado (p<0,001), uso exclusivamente de monta natural (p=0,002, OR=2,28 e IC95%=1,37-3,79) e a presença de aves nas propriedades (p=0,001). Na infecção por N. caninum essa chance aumentou em: fêmeas (p=0,031), propriedades sem aprisco (p<0,001) e sistema de criação semi-intensivo (p<0,001). Em relação ao histórico de problemas reprodutivos, ovelhas infectadas pelo N. caninum e T. gondii apresentaram redução da chance de apresentarem abortamento (p=0,044) e repetição de estro (p=0,025) respectivamente. O T. gondii esteve mais presente sorologicamente que o N. caninum em ovinos com histórico de distúrbios reprodutivos e apesar de suas semelhanças, diferiram epidemiologicamente em aspectos relacionados as características da criação como raça, sexo, sistema de criação, tipo de alimentação e manejo reprodutivo.

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Section: Discussionunclassified

Ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em ovinos com distúrbios reprodutivos e fatores de risco

et al. 2018

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“…However, numerous studies based on occurrence of antibodies against N. caninum have demonstrated that this parasite is present in sheep herds in all regions of Brazil, with prevalences ranging from 11.1% to 78% (Rossi et al, 2011;Correia et al, 2015;Guimarães et al, 2015;Oshiro et al, 2015;Consalter et al, 2020). In Brazil, Azevedo et al (2017) affirmed that researches regarding evaluation vertical transmission of N. caninum in naturally infected sheep in herds are still scarce in Brazil and worldwide.…”

Section: Introductionmentioning

confidence: 99%

Vertical transmission and kinetic of antibodies anti-Neospora caninum in naturally infected lambs in the semiarid region of Brazil

Feitosa

Costa

Bezerra

et al. 2021

Rev. Bras. Parasitol. Vet.

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Aimed with this study to evaluate vertical transmission of Neospora caninum in naturally infected sheep and to monitor the kinetics of antibodies against this protozoon in their lambs. Therefore, 48 pregnant ewes, from five herds, were divided into two groups: G1 - positive for anti-N. caninum antibodies, with 19 animals; and G2 - seronegative, with 29 animals. Blood samples were taken from the ewes and their lambs, immediately after birth, before ingesting colostrum, and 2, 7, 14, 21, 28, 35, 42, 49 and 56 days after birth. Analysis on serum antibodies was performed using the indirect immunofluorescent antibody test. Among the 19 seropositive mothers, six (31.6%) gave birth to lambs seropositive before ingesting colostrum and it was found that these lambs remained positive until the end of the study (56 days). Only one of the lambs, from a ewe that presented an antibody titer of 200, seroconverted after ingestion of colostrum. All the lambs that had been born from negative mothers remained negative throughout the experimental period. It was concluded that transplacental transmission was an important form of diffusion of N. caninum in the herds studied and that seropositive lambs maintained circulating antibodies during the period analyzed.

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“…Slides were prepared containing tachyzoites of N. caninum (NC-1 strain) and T. gondii (RH strain), obtained through cell culturing as described by Locatelli-Dittrich et al [26]. Serum samples with titers 1:25 for N. caninum and 1:40 for T. gondii were considered positive as described by Guimarães et al [22]. Sera were analyzed until reaching the final titer.…”

Section: Indirect Fluorescent Antibody Test (Ifat)mentioning

confidence: 99%

Detection of Neospora caninum and Toxoplasma gondii in Semen of Naturally Infected Rams

Koch

Dittrich

Weiss

et al. 2019

Acta Scientiae. Vet.

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Background: Neospora caninum and Toxoplasma gondii are closely related cyst-forming apicomplexan parasites identified as important causes of reproductive failure in cattle. Moreover, abortion cases attributed to N. caninum and T. gondii infection have been occasionally reported in sheep. Due to the relatively scarce information on the molecular detection of N. caninum in the semen of naturally infected rams, this study aimed to detect parasitic DNA in fresh semen samples and in frozen extended semen straws from male sheep from artificial inseminations centers in Southern Brazil.Materials, Methods & Results: Semen samples of 38 rams from artificial insemination centers were evaluated. Eleven rams were naturally infected (seropositive for anti-N. caninum and/or anti-T. gondii IgG) and were selected for fresh semen collection. We tested all the samples for the closely related protozoan T. gondii to detect a possible cross-reaction and co-infection, due to the close similarity with N. caninum. The indirect fluorescent antibody test was used to detect IgG antibodies in the 11 serum samples from rams. Fresh semen samples were collected from 11 rams on days 1, 50, 55, and 58 using an artificial vagina and ewe in estrus. Other 27 rams had their frozen extended semen straws analyzed. A total of 20 fresh semen samples and 27 frozen extended semen straws samples were used to detect the presence of N. caninum and T. gondii DNA by polymerase chain reaction (PCR). Nc-5 and B1 genes were used as target regions to detect N. caninum and T. gondii DNA, respectively. The presence of N. caninum DNA was confirmed in the third collection of a fresh semen sample of one seropositive ram. T. gondii DNA was detected in a fresh semen sample of one seropositive ram. The DNA sequences of 186 bp from N. caninum (GenBank accession: MH806393) and 492 bp from T. gondii (GenBank accession: MH793503) were obtained by sequencing, and analysis revealed 99% and 100% identity, respectively, compared with other sequences deposited at GenBank. N. caninum and T. gondii DNAs were not detected in any of the 27 frozen extended semen straws used for artificial insemination.Discussion: This study demonstrated the presence of N. caninum and T. gondii DNA in fresh semen samples of naturally infected rams. The non-detection of N. caninum and T. gondii DNA in frozen semen samples of rams could be due to the dilution that was used to prepare the semen straws (GGL diluent and 5% glycerol), since fresh semen samples were not diluted prior to the test. Moreover, in our study, the volume of frozen semen samples (0.25 mL) used for PCR was lower than the volume of sediment obtained from fresh semen (0.5 mL), and the fresh semen centrifugation to obtain the sediment may have grouped the tachyzoites, increasing the sensitivity of the technique employed. No high IgG serological titers were detected in the rams at the time they were eliminating the parasite through fresh semen. The final titer of anti-N. caninum and anti-T. gondii IgGs in serum was 1:100, suggesting chronic infection. It is suggested that a new parasite elimination pathway is occurring among rams used for reproduction, due to the presence of N. caninum and T. gondii DNA in fresh semen samples from seropositive animals. Although the detection of genomic DNA of N. caninum and T. gondii in semen does not necessarily imply the presence of infectious stages of the parasites and does not determine their viability, these results demonstrate the need for further studies. Our study also indicates the need to reinforce preventive measures for sheep in artificial insemination centers until the risks are evaluated, by performing serological examinations with anti-N. caninum and anti-T. gondii antibodies, for instance, to select the rams that will be used for breeding.

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Occurrences of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from four districts of Tocantins state, Brazilian Legal Amazon Region

Cited by 15 publications

References 37 publications

Ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em ovinos com distúrbios reprodutivos e fatores de risco

Ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em ovinos com distúrbios reprodutivos e fatores de risco

Vertical transmission and kinetic of antibodies anti-Neospora caninum in naturally infected lambs in the semiarid region of Brazil

Detection of Neospora caninum and Toxoplasma gondii in Semen of Naturally Infected Rams

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