Bovine hemoplasmas are bacteria found on the erythrocyte surface or free in the plasma of cattle. The aim of the present study was to evaluate the occurrence of 'Candidatus Mycoplasma haemobos' ('C. M. haemobos') in Holstein and Jersey cattle raised in Londrina and surroundings, northern region of the State of Parana, Southern Brazil. PCR testing directed to 16S rRNA gene fragment was performed to investigate the occurrence and characterize the molecular identity of 'C. M. haemobos'. A total of 264/433 (60.97%) blood samples were positive by PCR. Further alignment of 500-bp amplicons to available sequences at the GenBank database showed high identity (100%) to 'C. M. haemobos'. To the author's knowledge, this is the first molecular confirmation of the hemoplasma 'C. M. haemobos' in cattle from Brazil. Moreover, 'C. M. haemobos' was observed in high occurrence in dairy cattle, and may have significant impact in livestock production.

During this study, cats were immunized by the intranasal and rectal routes with crude rhoptry proteins of Toxoplasma gondii admixed with Quil-A. Twenty-five domestic short hair cats divided into five groups (n=5) were used during this evaluation: G1 and G3 cats received 200 μg of the rhoptry proteins with Quil-A (20 μg) by the intranasal and rectal routes, respectively; G2 and G4 cats received bovine serum albumin (BSA, 200 μg/dose) with Quil-A (20 μg); and G5 animals served as unvaccinated controls. All treatments were performed at days 0, 21, 42, and 63. The challenge was done with 800 cysts of the ME49 of T. gondii strain at day 70 (challenge day). The serum IgG, IgM, IgA, and fecal IgA antibody levels were evaluated by using the indirect enzyme-linked immunosorbent assay (ELISA). Some animals produced antibody levels beyond cut-off; however, two animals from G1 (OD(mean)=0.308, OD(cut-off)=0.200) and three from G3 (OD(mean)=0.254) demonstrated IgG levels on being challenged, with similar results occurring in two cats from G1 to IgM (OD(mean)=0.279, OD(cut-off)=0.200). Fecal IgA levels were detected in all G1 cats (OD(mean)=0.330, OD(cut-off)=0.065), and in one cat from G3 (OD(mean)=0.167). The serum and fecal humoral immune responses did not correlate with oocyst shedding. Oocyst shedding varied from 98.4% (G1), 87.5% (G2), 53.0% (G3), to 58% (G4), and was lower than that of G5 cats. The prepatent period of cats vaccinated intranasally (G1) was reduced from 6-9.6 to 2.8 days, suggesting protection of environmental contamination, considering cats as the primary source of contamination. The intranasally and rectally administered rhoptry vaccines were able to partially protect cats against T. gondii cysts on being challenged; however, the intranasal method of vaccination yielded better results relative to the rectal route.

We evaluated the humoral and cellular immune responses in pigs immunized intranasally with crude rhoptry proteins of Toxoplasma gondii plus Quil-A. The experiment used 13 mixed-breed pigs divided into the following three groups: G1 (vaccinated-challenged, n=6), which received the rhoptry vaccine (200(g/dose); G2 (adjuvant-challenged, n=4), which received PBS plus Quil-A; and G3 (unvaccinated-challenged, n=3), which was the control group. The treatments were performed intranasally at days 0, 21, and 42. Three pigs from G1 produced IgG and IgM antibody levels above the cut-off in the ELISA on the challenge day. Partial protection was observed in G1 at the chronic phase of infection when compared with G3. The preventable fractions were 41.6% and 6.5%, in G1 and G2, respectively. The results of this study suggest that rhoptry proteins plus Quil-A stimulated humoral, local, and systemic immune responses, which were able to partially protect the brain from cyst formation.

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The aim of the present study was to evaluate the seroprevalence of antibodies against Neospora caninum, obtained two years apart, among dairy cattle in a rural settlement in southern Brazil. Blood samples from 734 dairy cattle on 41 farms were collected at two different times: in 2012, 406 animals on 30 farms were used; and in 2014, 329 animals on 31 farms. Serum samples were obtained and were used to detect antibodies against N. caninum, by means of the indirect fluorescence assay (IFA). Animals with titers ≥ 100 were considered positive. The total serum prevalence of anti-N. caninum antibodies was 19.7% (145/736) among all the dairy cattle, comprising 23.1% (94/406) in 2012 and 15.5% (51/329) in 2014.Serum from 91 animals was tested in both trials: 11(12.1%) showed positivity in 2012 and 10 (11%) in 2014. The variables of age, sex and breed did not show any associations with seropositivity. Thus, we showed that the cattle in this settlement presented high levels of antibodies against N. caninum, and that IFA showed good efficacy for epidemiological studies. Key words: Neosporosis. Reproductive problems. Seropositive. ResumoO objetivo deste estudo foi avaliar a soroprevalência de anticorpos contra Neospora caninum em bovinos de leite de um assentamento rural, região sul do Brasil. Participaram do estudo um total de 734 bovinos de leite, 406 animais de 30 propriedades coletados em 2012, e 329 animais de 31 propriedades em 2014. Amostras de soro foram analisadas por meio da Reação de Imunofluorescência Indireta (RIFI), animais com títulos ≥100 foram considerados positivos. A soroprevalência total para anticorpos contra N. caninum foi 19,7% (145/736), 23,1 % (94/406) e 15,5% (51/329) em 2012 e 2014, respectivamente. Noventa e um animais tiveram amostras analisadas em ambos estudos, 11(12,1%) evidenciaram positividade em 2012 e 10 (11%) em 2014. Não houveram associações entre as variáveis estudadas (idade, sexo e raças) com a soropositividade para neosporose. Evidenciou-se com o presente estudo um alto nível de anticorpos contra N. caninum nos bovinos desse assentamento rural, bem como, a RIFI utilizada mostrou boa eficácia para estudos epidemiológicos. Palavras-chave: Neosporose. Problemas reprodutivos. Soropositivo.