Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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

Koch, Marilia de OliveiraDittrich, Rosangela LocatelliWeiss, Romildo RomualdoBergstein-Galan, Tácia GomesAguiar, Daniel MouraBrandão, Yara de OliveiraCruz, Amilcar ArenalBusch, Ana Paula BrennerMonteiro, Alda Lúcia Gomes

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. gondiiinfection have been occasionally reported in sheep. Due to the relatively scarce information on the molecular detection ofN. caninum in the semen of naturally infected rams, this study aimed to detect parasitic DNA in fresh semen samples andin 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 ramswere 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 tothe close similarity with N. caninum. The indirect fluorescent antibody test was used to detect IgG antibodies in the 11 serumsamples from rams. Fresh semen samples were collected from 11 rams on days 1, 50, 55, and 58 using an artificial vaginaand ewe in estrus. Other 27 rams had their frozen extended semen straws analyzed. A total of 20 fresh semen samples and27 frozen extended semen straws samples were used to detect the presence of N. caninum and T. gondii DNA by polymerasechain 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)...(AU)

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