Evaluation of caprine arthritis-encephalitis virus transmission in newborn goat kids / Estudo da transmissão do vírus da artrite-encefalite caprina em cabritos neonatos

Caprine arthritis encephalitis causes considerable losses in goat production. The main form of the caprine arthritis encephalitis virus transmission is through the ingestion of colostrum or milk from infected females. However, some transmissions cannot be explained in this manner. Therefore, this study aimed to evaluate transplacental transmission of caprine arthritis encephalitis virus. Blood samples were collected from 283 newborn kids of Anglo-Nubian and Saanen breeds born from seropositive and seronegative goats. Samples were collected immediately after birth and analyzed with agarose gel immunodiffusion and western blot. All samples were negative in the agarose gel immunodiffusion. However, the western blot test demonstrated that four kids were born positive for caprine arthritis encephalitis virus. This result indicates that although in a low frequency (1.4%), there is a possibility of transplacental transmission of small ruminant lentivirus.(AU)

A artrite encefalite caprina causa perdas consideráveis para a produção caprina. A principal forma de transmissão do vírus da artrite encefalite caprina é a ingestão de colostro ou leite de fêmeas infectadas. No entanto, algumas transmissões não podem ser explicadas por esta via. Dessa forma, este estudo teve como objetivo avaliar a transmissão do vírus da artrite encefalite caprina por via transplacentária (vertical). Foram realizadas coletas de sangue em 283 crias recém-nascidas das raças Anglo-Nubiana e Saanen, provenientes de progenitores soropositivos e soronegativos. As amostras foram coletadas logo após o nascimento e analisadas pelas técnicas de imunodifusão em gel de agarose e western blot. No teste de imunodifusão em gel de agarose, nenhum cabrito foi detectado reagente. Porém, no teste de western blot, quatro cabritos nasceram soropositivos. Esse resultado indica que, apesar de baixa frequência (1,4%), existe a possibilidade de transmissão via transplacentária do lentivírus de pequenos ruminantes.(AU)

Medium-term cryopreservation of rabies virus samples

Introduction The cryopreservation of rabies virus has been described in detail in the literature. To date, little information is available on the use of cryoprotective agents for cold preservation of this virus, and the available data focus only on short-term virus preservation. In this study, we investigated the medium-term cryopreservation of samples of rabies virus using different cryopreservation protocols. Methods The cryopreservation protocols for the rabies virus samples were performed at -20°C and were divided according to the variables of time and cryoprotectant type used. The laboratory tests (intracerebral inoculation of mice, viral titration and direct immunofluorescence) were performed at regular intervals (360 and 720 days) to assess the viability of the viral samples according to the different preservation techniques used. Results After 1 year of cryopreservation, the fluorescence intensity of intracellular corpuscles of the rabies virus and the median survival time of the mice differed between the positive controls and the treatments with the cryoprotectants. After 2 years, most of the samples subjected to the cryopreservation protocols (including the controls) did not produce fluorescence. However, the virus samples exposed to the cryoprotectant sucrose (68% solution) responded positively in the direct immunofluorescence assay and in the intracerebral inoculation of the mice. Conclusions Medium-term cryopreservation of the rabies virus inactivates the viral sample. However, the cryoprotectant agent sucrose (68%) produces a preservative effect in cryopreserved rabies virus samples. .