Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii that affects reproductive performance in small ruminants. Although the T. gondii life cycle is well understood since 1960s, several aspects related to its infection remain unclear. In the present study we hypothesized that sheep inseminated with T. gondii-contaminated semen would develop toxoplasmosis. In order to test that hypothesis, 41 sheep were experimentally infected with semen spiked with the organism. Females were divided in three groups (G1-G3): (a) females in G1 group were inseminated with semen containing 6.5 x 10(4) tachyzoites; (b) females in G2 group with semen containing 4 x 10(7) tachyzoites; and (c) females in G3 group with tachyzoite-free semen (control group). To confirm T. gondii infection via semen, serological tests were performed using indirect immunofluorescence reaction and the detection of parasite DNA in the blood stream using the nested PCR test. While in G1 group only 5/15 (33.3%) of the females presented seroconversion, all sheep in G2 15/15 (100%) seroconverted. The nested PCR test showed that 14/15 (93.3%) of the females in the G1 and 14/15 (93.3%) in the G2 group were positive for T. gondii while in the G3 group all samples were negative. In addition, ultra-sound test evidenced that in sheep presented embryonic reabsorption in animals from the infected groups. In conclusion, insemination using fresh semen experimentally contaminated with different infectant doses of T. gondii tachyzoites was able to infect sheep, leading to the possibility of toxoplasmosis transmission via semen.

Yeasts are considered a useful system for the development of vaccines for human and veterinary health. Species such as Saccharomyces cerevisiae and Pichia pastoris have been used successfully as host organisms for the production of subunit vaccine antigens. In the last two decades, these organisms have been also explored as vaccine vehicles enabling the delivery of antigens such as proteins and nucleic acids. The employed species of yeasts possess a GRAS status (Generally Recognized as Safe) for the production of therapeutic proteins, besides promoting immunostimulation due to the properties of their wall cell composition. This strategy allows the administration of nucleic acids orally and a specific delivery to professional antigen-presenting cells (APCs). In this review, we seek to outline the development of whole yeast vaccines (WYV) strategies as carriers of nucleic acids in different approaches in the medical field, as well as the immunological aspects of this vaccine strategy. The data presented here reveal the application of this platform in promoting effective immune responses in the context of prophylactic and therapeutic approaches against infectious diseases, in addition to the possible use in immunotherapies for different types of cancer.

The classical swine fever (CSF) is a highly contagious viral disease of pigs and wild boar. The CSF causes great economic losses for pork production and the occurrence of the disease is notifiable to the OIE. The objective of this work was to identify and characterize CSF virus isolates from Brazil. Seven viral isolates were obtained and the full-length E2 sequences were analyzed. Phylogenetic analysis revealed a different segregation pattern between Brazilian isolates and members of subgenotype 1.1, forming a separate group within genotype 1. Genetic distance analysis suggested the existence of two new subgenotypes, designated subgenotypes 1.5 and 1.6.

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