Toxoplasma gondii transmission by artificial insemination in sheep with experimentally contaminated frozen semen

Abstract

Toxoplasma gondii is a parasite considered one of the major causes of reproductive problems in sheep. Furthermore, the presence of the agent in ram semen urges the possibility of sexual transmission in this species. The aim of this study was to evaluate if ram's frozen semen spiked with T. gondii tachyzoites would be able to cause infection in sheep by laparoscopic artificial insemination (AI). Nine ewes tested seronegative to anti-T. gondii antibodies by the modified agglutination test (MAT) were superovulated and inseminated to collect embryos. Animals were divided into two groups: G1 (n = 5), ewes inseminated with semen containing 4 × 10 tachyzoites; and G2 (n = 4), ewes inseminated with tachyzoite-free semen (control group). To confirm infection, ewe's blood samples were collected on days -14, -7, 0, 7, 14, 21, 28, 35, 49 and 57 after AI for analysis by MAT and PCR. Tissue samples of these ewes were also collected for histopathology and immunohistochemistry (IHC). Seven days after AI, all ewes of group G1 had specific antibodies to T. gondii, while those of G2 were negative. Toxoplasma gondii DNA was detected in the blood of one ewe and parasites were observed in tissues of all five animals inseminated with contaminated semen, indicating that semen freezing protocol does not affect T. gondii transmission by artificial insemination in sheep.

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

“…Propriedades que adotam exclusivamente a monta natural com manejo reprodutivo apresentaram um risco de infecção a T. gondii que foi 2,8 vezes maior em comparação com aqueles que também empregam alguma biotecnologia; sendo isso reflexo de um controle sanitário mais rígido nessas propriedades que são mais tecnificadas. No entanto, deve-se ater a presença do parasita em amostras de sêmen (Moraes et al 2010) uma vez que se mantêm viável mesmo após o processo de envase e congelamento, servindo de via de infecção a fêmeas (Consalter et al 2017).…”

“…A soropositividade para essas enfermidades está relacionada com a contaminação ambiental (Frenkel et al 1975), principalmente em regiões úmidas devido a formação de um microambiente favorável à manutenção de oocistos viáveis no solo (Pita Gondim et al 1999, Silva et al 2003, havendo também correlação entre as fontes de água e a infecção oral (Romanelli et al 2007). Há ainda a possibilidade de transmissão congênita e via sêmen (Lopes et al 2013, Azevedo Filho et al 2017, Consalter et al 2017 causando transtornos reprodutivos nas fêmeas infectadas, como absorção fetal, morte embrionária e aborto (Syed-Hussain et al 2015).…”

Viability of Toxoplasma gondii in cattle semen cryopreserved with different concentrations of cryoprotectant

“…Using semen cryopreserved with a commercial formulation containing 3% glycerol and contaminated with 10 7 tachyzoites of T. gondii frozen in liquid nitrogen and thawed, Consalter et al (2017) found vigor and motility of 4% and 35%, respectively. To confirm viability, mice were inoculated with tachyzoites of T. gondii (1 x 10 6 ) + sperm (20 x 10 6 ) by the intraperitoneal route, all of which became ill and died within two weeks.…”

Pathogens in Processed Ram Semen and Approaches for Their Elimination

“…Importantly, it was shown, that intrauterine contamination with tachyzoites of Toxoplasma gondii during artificial insemination can establish toxoplasmosis in ewes and cause reproductive pathologies, associated to the occurrence of embryonic death and reabsorption, fetaldeath and mummification, abortion, stillborn, and neonatal mortality, as summarized by Moraes et al (2010). The process of sperm cryopreservation did not inhibit the infectious ability of tachyzoites of Toxoplasma gondii (Consalter et al, 2017).…”