Transferência de imunidade passiva (TIP) e dinâmica de anticorpos específicos em bezerros naturalmente expostos para as viroses respiratórias / Passive immune transfer (PIT) and dynamics of specific antibodies in calves naturally exposed to the respiratory viruses

Esta pesquisa avaliou a TIP e a dinâmica de anticorpos (ACs) específicos em bezerros naturalmente expostos aos agentes causadores da doença respiratória bovina (DRB). Foram selecionados 19 bezerros Holandeses alimentados com colostro proveniente de doadoras vacinadas para DRB. Amostras de soro foram obtidas antes e após a ingestão do colostro (48h) para a soroneutralização (SN). Os valores médios (log2) detectados após colostragem foram de 11,5±1,6 (BVDV), 8,8±1,3 (BoHV-1), 5,5±1,6 (BRSV) e 8,4±1,5 (BPIV-3). Cinco bezerros foram criados do nascimento aos 240 dias de vida, observando-se decréscimo nos títulos de ACs para BVDV, BoHV-1 e BPIV-3 ao longo do tempo (P≤0,001). As taxas de infecções detectadas entre o D14 e o D240 foram de 40% (2/5), 20% (1/5), 80% (4/5), e 60% (3/5), respectivamente, para BVDV, BoHV-1, BRSV e BPIV-3. A maioria dos bezerros manifestou broncopneumonia após as infecções virais. Os bezerros apresentaram ACs para todas as viroses às 48 horas de vida, porém os títulos adquiridos para o BRSV foram baixos. A susceptibilidade para as infecções variou de acordo com os níveis e a duração dos títulos de ACs maternos.(AU)

This research evaluated the PIT and the dynamics of specific antibody (Ab) for calves naturally exposed to the viral agents involved in Bovine Respiratory Disease (BRD). Nineteen Holstein calves fed colostrum from vaccinated donors for DRB. Serum samples were obtained before and after colostrum intake (48h) for serum neutralization (SN). Mean values (log2) detected after colostrum feeding were 11.5±1.6 (BVDV), 8.8 ±1.3 (BoHV-1) 5.5±1.6 (BRSV) and 8.4±1.5 (BPIV-3). Five calves were raised from birth to 240 days of life and presented a decrease in Ab titers for BVDV, BoHV-1 and BPIV-3 over time (P≤ 0.001). Infection rates from D14 to D240 were of 40% (2/5), 20% (1/5), 80% (4/5) and 60% (3/5), respectively for BVDV, BoHV-1, BRSV and BPIV-3. Most of the calves presented bronchopneumonia after seroconversion to the virus. Calves presented Ab for all viruses at 48 hours of life, however BRSV Ab titer were low. Levels and persistence of maternal antibody titers determined the susceptibility to viral infections.(AU)

Influência da vacinação materna na transferência de imunidade passiva contra as viroses respiratórias dos bovinos / Influence of maternal vaccination for the passive immune transfer against bovine respiratory viruses

O objetivo deste estudo longitudinal foi avaliar a influência da vacinação materna na transferência de anticorpos (ACs) contra as viroses respiratórias em bezerros. Para tanto, vacas e bezerros foram distribuídos em dois grupos conforme a realização (VAC, n=6) ou não (NVAC, n=4) da vacinação no pré-parto. Amostras sanguíneas foram obtidas após a parição (D0); em seguida, apenas os bezerros foram acompanhados até D180. ACs séricos foram determinados pela vírus-neutralização (VN) contra BVDV, BoHV-1, BRSV e BPI3-V. Vacas VAC apresentaram diferenças para ACs contra BoHV-1 (P=0,01) em D0. As frequências (%) de bezerros soropositivos para BoHV-1 foram maiores em VAC do D2 ao D120; para BRSV em D4, D8, D10 e D150 (P≤0,08); medianas de ACs contra BoHV-1 em VAC do D2 ao D120 (P=0,08). A vacinação das vacas no pré-parto foi fundamental para a transferência e a duração de ACs contra BoHV-1 e BRSV, porém o protocolo adotado não foi eficiente para o aumento de ACs para BVDV e BPI3-V. A eficácia parcial da vacinação materna não inviabiliza a sua recomendação devido à importância do Herpesvírus e do BRSV na DRB, porém estratégias para a melhoria nas respostas imunes contra as demais viroses devem ser estabelecidas.(AU)

The aim of this longitudinal research was to evaluate the influence of maternal vaccination for the passive immune transfer of antibodies (Abs) against respiratory viruses in calves. Therefore, cows and calves sourced from two groups according to having received (VAC, n=6) or not (NVAC, n=4) of vaccination at pre-partum period. Blood samples of cows and calves harvested after parturition (D0), and then only calves followed until the age of 180 days. Abs performed by virus neutralization (VN) against BVDV, BoHV-1, BRSV and BPI3-V. VAC cows presented differences for Abs against BoHV-1 (P=0.01) in D0. Frequencies (%) of seropositive VAC calves for BoHV-1 were higher in D2 to D120; to BRSV D4, D8, D10 and D150 (P≤0.08); higher medians of Abs against BoHV-1 in VAC at D2 up to D120 (P=0.08). Partial efficacy of vaccination of cows does not impair its recommendation due to the importance of Herpesvirus and BRSV in BRD, but strategies for improvement in immune responses against other viruses should be established.(AU)

Associação da ocorrência do ectima contagioso (ORF vírus) em ovinos com os cuidadores desses animais / Occurrence of the Association contagious ecthyma (ORF virus) in sheep with these animals' caregivers

A enfermidade ectima contagioso está difundida em todo o estado de São Paulo. Foram amostrados 42 (8,64%) cuidadores de animais e 444 (91,36%) ovinos (n=486). A prevalência de reagentes para vírus-neutralização foi de 67% (IC95%=62-71%) nos ovinos, e em seus cuidadores de 76% (IC95%=63-89%), sendo P=0,22, ou seja, não houve diferença estatística significativa entre as espécies. A distribuição dos títulos teve diferença estatística significativa entre as espécies, com P=0,0048. As variações de titulação foram de 0,6 a 2,1 tanto nos ovinos quanto nos seus cuidadores. Dentre os 42 cuidadores de ovinos participantes do estudo, 32 apresentaram títulos de anticorpos expressos por log10 acima de 0,6.(AU)

These diseases are all widespread in the State of São Paulo. 42 (8.64%) animal caregivers and 444 (91.36%) sheep (n=486) were sampled. The reagents Prevalence paragraph virus neutralization was 67% (95% CI = 62-71%) in sheep and 76% (95% CI = 63-89%) for caregivers, with P=0.22 not being a statistically significant difference between the species. One of the distribution titles had significant difference between statistics as species with P=0.0048. The titration variations were 0.6 to 2.1, both in sheep and their caregivers. Among the 42 sheep caregivers participating in the study, 32 had antibody securities denominated in log10 above 0.6.(AU)

Delayed Schwann cell and oligodendrocyte remyelination after ethidium bromide injection in the brainstem of Wistar rats submitted to streptozotocin diabetogenic treatment

Schwann cell disturbance followed by segmental demyelination in the peripheral nervous system occurs in diabetic patients. Since Schwann cell and oligodendrocyte remyelination in the central nervous system is a well-known event in the ethidium bromide (EB) demyelinating model, the aim of this investigation was to determine the behavior of both cell types after local EB injection into the brainstem of streptozotocin diabetic rats. Adult male Wistar rats received a single intravenous injection of streptozotocin (50 mg/kg) and were submitted 10 days later to a single injection of 10 æL 0.1 percent (w/v) EB or 0.9 percent saline solution into the cisterna pontis. Ten microliters of 0.1 percent EB was also injected into non-diabetic rats. The animals were anesthetized and perfused through the heart 7 to 31 days after EB or saline injection and brainstem sections were collected and processed for light and transmission electron microscopy. The final balance of myelin repair in diabetic and non-diabetic rats at 31 days was compared using a semi-quantitative method. Diabetic rats presented delayed macrophage activity and lesser remyelination compared to non-diabetic rats. Although oligodendrocytes were the major remyelinating cells in the brainstem, Schwann cells invaded EB-induced lesions, first appearing at 11 days in non-diabetic rats and by 15 days in diabetic rats. Results indicate that short-term streptozotocin-induced diabetes hindered both oligodendrocyte and Schwann cell remyelination (mean remyelination scores of 2.57 ± 0.77 for oligodendrocytes and 0.67 ± 0.5 for Schwann cells) compared to non-diabetic rats (3.27 ± 0.85 and 1.38 ± 0.81, respectively).