Acta Scientiae Veterinariae 影响因子-刊鹿论文编译

Detection of Neospora caninum and Toxoplasma gondii in semen of naturally infected rams

Abstract:

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\xa0 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.

Author Listing： Marília de Oliveira Koch;Rosangela Locatelli Dittrich;Romildo Romualdo Weiss;Tácia Gomes Bergstein-Galan;Daniel Moura Aguiar;Yara de Oliveira Brandão;Amilcar Arenal Cruz;Ana Paula Brenner Busch;Alda Lúcia Gomes Monteiro

Volume： 47

Pages： None

DOI： 10.22456/1679-9216.92090

Language： English

Journal： Acta Scientiae Veterinariae

Acta Scientiae Veterinariae

ACTA SCI VET

影响因子：0.2

是否综述期刊：否

是否OA：否

是否预警：不在预警名单内

发行时间：2002

ISSN：1678-0345

发刊频率：Tri-annual

收录数据库：SCIE/Scopus收录

出版国家/地区：BRAZIL

出版社：Universidade Federal do Rio Grande do Sul

期刊介绍

ASV is concerned with papers dealing with all aspects of disease prevention, clinical and internal medicine, pathology, surgery, epidemiology, immunology, diagnostic and therapeutic procedures, in addition to fundamental research in physiology, biochemistry, immunochemistry, genetics, cell and molecular biology applied to the veterinary field and as an interface with public health.The submission of a manuscript implies that the same work has not been published and is not under consideration for publication elsewhere. The manuscripts should be first submitted online to the Editor. There are no page charges, only a submission fee.

ASV 关注的论文涉及疾病预防、临床和内科、病理学、外科、流行病学、免疫学、诊断和治疗程序的各个方面，细胞和分子生物学应用于兽医领域并作为公共卫生的接口。提交手稿意味着同一作品尚未出版，也未考虑在其他地方出版。稿件应首先在线提交给编辑。没有页面费用，只有提交费。

年发文量	121
国人发稿量	1
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自引率	0.0%
平均录取率	容易
平均审稿周期	较慢,6-12周
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偏重研究方向	VETERINARY SCIENCES-
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