RESUMO O objetivo foi demonstrar a transmissão iatrogênica de lentivírus de pequenos ruminantes (LVPR) de caprinos para ovinos e a transmissão horizontal entre ovinos. O estudo foi conduzido em propriedade com criação não consorciada de caprinos e ovinos, monitorada para ocorrência de lentiviroses, a partir de acompanhamento clínico e testes de immunoblotting (IB), imunodifusão em gel de agarose (IDGA) e reação em cadeia da polimerase do tipo nested (nPCR). Resultados positivos no rebanho ovino não haviam sido observados até então. Por outro lado, sabia-se que o rebanho caprino leiteiro era positivo. Por este motivo, a propriedade realizava programa de controle da artrite-encefalite caprina (CAE). O estudo foi delineado em um lote de ovinos que apresentou animais positivos para LVPR na nPCR. Verificou-se que três animais neonatos deste lote foram rejeitados por suas mães e por isso receberam leite do rebanho caprino. Estes três animais permaneceram com outros 20 ovinos de mesma faixa etária, totalizando 23 animais. Após um ano, durante a realização do monitoramento, dos 23 animais do lote, 11 apresentaram resultados positivos na nPCR e três demonstraram soroconversão por IB. Dos animais que haviam recebido leite do rebanho caprino, dois tiveram resultados positivos na nPCR e no IB. Os 11 animais positivos na nPCR foram acompanhados, verificando-se que cinco animais não apresentaram mais resultados positivos na nPCR, nem soroconverteram; dois continuaram apresentando resultados positivos na nPCR, mas negativos no IB e IDGA e quatro apresentaram-se positivos na nPCR, no IB e no IDGA. Dessa forma, foi possível demonstrar a infecção interespecífica de forma iatrogênica e a ocorrência de transmissão horizontal do lentivírus caprino entre ovinos.

SUMMARY The objective of this study was to demonstrate iatrogenic transmission of small ruminant lentivirus (SRLV) from goats to sheep and horizontal transmission between sheep. The study was conducted on a farm with separate goat and sheep rearing, and animals were monitored for lentivirus occurrence by clinical examination and testing by immunoblotting (IB), agar gel immunodiffusion (AGID), and nested polymerase chain reaction (nPCR). Positive results had not been observed in the sheep flock until this study. Conversely, virus positive dairy goats were known. For this reason, the farm performed the caprine arthritis-encephalitis (CAE) control program. The study was designed with a sheep group that presented positive animals for SRLV by nPCR. It was verified that three newborn animals in this group were rejected by their mothers and consequently received milk from the goat herd. These three animals remained with another 20 sheep of the same age, totaling 23 animals. After one year, during monitoring, 11 of the 23 animals in the group presented positive results in the nPCR and three demonstrated seroconversion by IB. Of the animals that had received goat milk, two had positive results in the nPCR and IB. The 11 animals positive in the nPCR were followed and it was verified that five animals did not present further positive results in the nPCR, nor seroconversion; two continued presenting positive results in the nPCR but were negative in the IB and AGID and four were positive in the nPCR, IB, and AGID. Thus, it was possible to demonstrate iatrogenic interspecific infection and the occurrence of horizontal caprine lentivirus transmission among sheep.

RESUMO: 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.

ABSTRACT: 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.

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.