Resposta humoral de bovinos vacinados contra as toxinas botulínicas tipos c e dem diferentes faixas etárias / Humoral response of vaccinated cattle against toxins of Clostridium botulinum types c and d at different ages

Foi verificada pelo teste de ELISA indireto a resposta humoral contra os toxoides botulínicos C e D em bovinos de diferentes idades. O estudo envolveu 90 animais, que foram divididos em três grupos (n = 30), de acordo com a sua faixa etária; inferior a 2 anos de idade (G1), entre 2 e 5 anos (G2) e superior a 5 anos (G3). Os grupos experimentais foram vacinados com duas doses de vacina antibotulínica bivalente (C e D) comercial, nos dias 0 e 42 após a primo-vacinação (booster). Na avaliação, quando realizada 30 dias após o booster, os animais do G3 apresentaram maior produção de anticorpos (p < 0,05) em relação aos demais grupos. Entre o G1 e G2 não houve diferença significativa na resposta humoral contra a toxina C, no entanto, contra a toxina D, os animais do G1 apresentaram maior produção de anticorpos. Todos os grupos produziram uma resposta significativa de anticorpos contra as toxinas botulínicas após a 2ª dose da vacina bivalente comercial, principalmente contra o tipo D.

Humoral response of vaccinated cattle against toxins of clostridium botulinum types C and D at different ages. Cattle humoral response against type C and D botulinum toxoids (indirect ELISA) was verified in animals of different ages. The animals (n = 90) were divided in three groups (n = 30): group one (G1): less than two years old; group two (G2): from 2 to 5 years old; group three (G3): more than 5 years old. The groups were vaccinated with two doses [0 and 42 days after primary vaccination (booster)] of bivalent (C and D) antibotulinum vaccine. Group three had higher antibody production (p ≤ 0.05) compared to the other groups, 30 days after the booster. There was no difference (G1 and G2; p ≥ 0.05) in the humoral response against C toxin, however, against D toxin, group one had higher antibody production. It was possible to conclude that after two doses of the commercial bivalent vaccine all groups produced a significant antibody response against botulinum toxins, especially against D type.

Neonatal immune response of Brazilian beef cattle to vaccination with clostridium botulinum toxoids types C and D by indirect ELISA

Types C and D strains of Clostridium botulinum are commonly related to avian and mammalian botulism. Although there are numerous vaccine recommendations, little research has been conducted to indicate the real effectiveness of vaccine timing or the ideal immunization protocol for young beef calves. Four commercially available vaccines, two bivalent (Clostridium botulinum types C and D; vaccines 1 and 2) and two polyvalent (all Clostridium spp. including Clostridium botulinum types C and D; vaccines 3 and 4), that are currently used in Brazilian herds, were tested in order to verify the maternal immune response. One hundred cows, divided into four vaccinated groups and one unvaccinated group, were given a two-dose subcutaneous immunization, at day zero, followed by a second dose given at 42 days post-vaccination, which corresponded to 40 days before birth. Serum samples (n = 75) were collected only from healthy neonatal calves at 0, 7, 45 and 90 days post-calving (DPC) and subjected to indirect ELISA using the purified C and D holotoxins as capture antigens. The serological profile showed that all vaccines were able to induce a satisfactory neonatal immune response to both holotoxins at 7 DPC. However, at 45 and 90 DPC, a significant reduction (p < 0.05) was observed in the antibody level against C and D holotoxins in all tested vaccines. Neonatal immunization in calves is compromised by significant levels of maternal antibodies so that the necessity of planning a calf vaccination program involves assessment of disease risks at the production site. Finally, our findings represent the first demonstration of maternal immunity transferred to neonatal beef calves, including immunity levels after vaccination against Clostridium botulinum toxoids C and D.

Soroprevalência de Maedi-Visna em ovinos na região de Araçatuba, SP / Occurrence of Maedi-visna in sheep from Araçatuba region - SP - Brazil

The seroprevalence of Maedi-Visna in sheep from Araçatuba region - SP, was determined and correlated to age, gender, breed, or sheep production systems. Blood samples were collected from 444 sheep, aging from two to 12 year-old. Both sexes and different breeds were sampled in 20 farms of this region. Physical examination was performed in all animals. Agar gel immunodiffusion test kit was used to diagnose in serum samples. Twelve animals, from five different farms, were AGID positive, yielding a seroprevalence of 2.7%, with no correlation among breed, gender, or sheep production systems and the detection of the disease. No animal considered positive for Maedi-Visna showed clinical signs compatible with Maedi-Visna.

A Bayesian approach to estimate the accuracy of "in-house" ELISA assay to measure rabies antibodies from compulsory vaccinated dogs and cattle

Rabies is a vaccine-preventable disease that causes acute encephalitis in mammals, and it is still a significant public health problem in numerous countries. lnfected dogs represent the main vectors involved in human rabies. Additionally, cattle rearing close to geographic areas where vampire bats are found presents an important connection with rural epidemiology. We applied two "in-house" enzyme-linked immunosorbent assay (ELISA) methodologies, considered alternatives to measure antibodies from vaccinated dogs and cattle, without employing the gold standard approach. The ELISA assays were performed on individual serum samples taken from domestic adult dogs and cows compulsory vaccinated against rabies (147 urban dogs and 64 cows; n equal 211). The sandwich and liquid-phase competitive ELISA (scELlSA and ipcELlSA). considered "in-house" assays. were performed according to previous works. The only statistical methodology that allows this study is the Bayesian approach, developed to replace the conventional Hui-Walter paradigm. For conditional independent Bayesian model (one population, two tests and no gold standard) the prior information for sensitivity and specificity of each test, mode, prevalence and transformed (alpha, beta) were submitted to Bayesian inference. The "in-house" IpcELISA revealed 16 - out of 261 serum samples - negative results, whereas in scELISA all results were positive. The Bayesian approach showed that prior information was specified for all parameters; posterior medians were SescELISA 89%, SpscELISA 88%, SPipcELISA 95% SeipcELISA 98%, and prevalence (pi) of 99%, without the use of gold standard analysis to measure specific anti-rabies antibodies