Congenital persistent infection with bovine viral diarrhea virus not observed in piglets.

This study was designed to determine whether congenital persistent infection occurs in piglets from gilts experimentally inoculated with bovine viral diarrhea virus type 2 (BVDV-2). Six pregnant gilts were divided into 2 groups, infected (n = 4), and control (n = 2). The gilts were inoculated at 45 days gestation. Piglets were assessed for 35 days following birth with nasal swab and blood sample collections every 72 hours. Reverse transcriptase-polymerase chain reaction (RT-PCR) tests were performed for direct diagnosis of virus in blood and nasal swabs, and virus neutralization was used for antibody detection. Transplacental transmission of BVDV-2 did not occur. Piglets were born free of the virus and did not shed BVDV during the experimental period.

Infection congénitale persistante par le virus de la diarrhée virale bovine non observée chez les porcelets. Cette étude a évalué l'occurrence d'infection congénitale persistante chez des porcelets nés de cochettes inoculées expérimentalement avec le virus BVDV-2. Six cochettes gestantes ont été divisées en deux groupes, infectées (n = 4) et témoins (n = 2). L'inoculation a eu lieu à 45 jours de gestation. Les porcelets ont été évalués pendant 35 jours par prélèvement d'écouvillons nasaux et d'échantillons de sang toutes les 72 heures. Des tests d'amplification en chaîne par la polymérase avec la transcriptase réverse (RT-PCR) ont été effectués pour le diagnostic direct dans le sang et les écouvillons, et la neutralisation virale pour l'évaluation sérologique. La transmission transplacentaire de BVDV-2 n'a pas été mise en évidence car les porcelets sont nés sans virus et n'ont pas éliminé le BVDV au cours de la période expérimentale.(Traduit par les auteurs).

Phagolysosomal activity of macrophages in Nile tilapia (Oreochromis niloticus) infected in vitro by Aeromonas hydrophila: Infection and immunotherapy.

The biochemical mechanisms involved in phagocytosis and the intracellular survival of Aeromonas hydrophila (Ah) in host macrophages (MΦs) are complex processes that affect infection success or failure. Thus, in the present study, we described the in vitro infection of Nile tilapia MΦs by a homologous bacterium and tested the effects of anti-A. hydrophila immunoglobulin Y (IgY) on the phagolysosomal activity and intracellular survival of the pathogen. The anti-Ah IgY modulated lysosomal acid phosphatase (LAP) activity as well as the production of reactive oxygen intermediates (ROIs) and nitric oxide (NO), thereby potentiating phagocytosis and the elimination of Ah. Thus, we assume that the specific IgY had a beneficial effect on infection control and postulated the use of the Nile tilapia MΦs as an important in vitro experimental model for the functional and therapeutic study of Ah infection.

Validation of IgY for the diagnosis of Streptococcus agalactiae-caused endocarditis and bacterial meningitis in Nile tilapia (Oreochromis niloticus).

Streptococcus agalactiae (Sta), which belongs to Lancefield group B, causes sepsis, endocarditis and bacterial meningitis in human neonates and Nile tilapia. Because the pathophysiology of Sta infection is partially similar in both species, the identification of biomarkers for the diagnosis and study of this disease is of importance for human and animal health. Therefore, in the present study, we produced an immunoglobulin Y (IgY) by immunizing laying hens with Sta proteins and evaluated its ability to detect Sta in paraffinized tilapia brain and cardiac tissue by direct immunofluorescence (IMF) and indirect immunohistochemistry (IHC). The IgY produced was effective in the diagnosis of Sta infection in Nile tilapia, justifying the use of this species as a biomodel for the study of this disease.

Escolaridade e volume de produção têm associação com a percepção de risco de produtores de leite no uso de produtos veterinários / Schooling and volume of production have association with the risk perception of milk producers in the use of veterinary products

O presente estudo teve por objetivo avaliar a correspondência entre fatores socioeconômicos de 171 produtores de leite (escolaridade, volume de produção diária e tempo na atividade) de 96 municípios do Estado de São Paulo, e a percepção de risco no uso de produtos veterinários, por meio de entrevista individual e da análise de correspondência múltipla. Produtores com grau de escolaridade fundamental tendem a ordenhar animais tratados com carrapaticidas, não descartar o leite de vacas em tratamento para mastite, não receber bonificação por qualidade e não usar EPIs. Já produtores com grau de instrução superior tendem a declarar que descartam o leite de vacas em tratamento para a mastite, a receber bonificação por qualidade, a participar de treinamento e a usar EPIs. Produtores com menos de 50 litros de leite diários tendem a declarar que não observam o período de carência dos produtos veterinários e são os que mais responderam incorretamente o período de carência de dois produtos empregados na propriedade, vermifugam animais em lactação e não recebem bonificação por qualidade. Produtores com mais de 500 litros de leite diários tendem a declarar que observam o período de carência dos produtos veterinários, tendem a responder corretamente o período de carência de dois produtos, a receber bonificação por qualidade, a participar de treinamento e a usar EPIs. Foi possível evidenciar que dentro das variáveis selecionadas há categorias ou grupos de produtores de leite para os quais o perigo sanitário é mais visível e outros para os quais o perigo é menos visível. Nesse contexto, é necessário e urgente a execução de programas sanitários contemporâneos nas unidades rurais de produção de leite, a atualização dos serviços de assistência técnica e extensão rural (pública e privada), com enfoque distinto e complementar ao atual e o desenvolvimento de ações efetivas de educação sanitária.

The present study aimed to evaluate the correspondence between socioeconomic factors of 171 milk producers (schooling, daily production volume and time in activity), of 96 counties in the state of São Paulo, and the risk perception in the use of veterinary products through individual interview and multiple correspondence analysis. Producers with low schooling tend to milk animals treated with acaricides, not to discard the milk of cows treated for mastitis, to receive no bonus for the quality of milk and not to use personal protective equipment (PPE). In contrast, producers with higher education tend to declare that they discard milk from cows treated for mastitis, to receive bonus for milk quality, to participate in training and use PPE. Producers with less than 50 liters of milk per day tend to declare that they do not observe the lack period of veterinary products, and when mentioned the lack period of two products more incorrectly answered, use vermifuge in lactating animals and do not receive bonus for milk quality. Producers with more than 500 liters of milk per day tend to declare they observe the lack period of veterinary products, to answer correctly the lack period of two products, to receive bonus for quality, to participate in training and to use PPE. It was possible to evidence that within the selected variables there are categories or groups of milk producers for whom the sanitary hazard is more visible and others for whom the hazard is less visible. In this context, it is necessary and urgent the execution of contemporary sanitary programs in rural units of milk production, the update of services of technical assistance and rural extension (public and private), with different approach and complementary to the currentand the development of effective sanitary education actions.

Estratégia para erradicação de focos da Doença de Aujeszky em suínos no Estado de São Paulo / Strategy for eradication of outbreaks of Aujeszky's Disease in pigs in the São Paulo state

Este trabalho teve como objetivo a avaliação de duas estratégias para erradicação de focos da doença de Aujeszky (DA) em suínos criados comercialmente no estado de São Paulo. Foram identificados dois focos da enfermidade, no município de Cerqueira César, um apresentando somente animais sororreagentes (Foco 1) e outro, casos clínicos da doença (Foco 2). Foram avaliadas duas estratégias de erradicação, uma por eliminação dos sororreagentes e outra por despovoamento gradual, com acompanhamento durante 12 meses. A erradicação por eliminação dos sororreagentes foi aplicada no Foco 1 e compreendeu na identificação por exame sorológico, isolamento e abate dos positivos; vacinação dos negativos e reposição no plantel com animais provenientes de propriedade livre. No início dos trabalhos, 68% do plantel era positivo e ao final 51%. No Foco 2 utilizou-se o despovoamento gradual, onde todos os animais foram enviados ao abate sanitário, realizado vazio sanitário nas instalações, seguido pelo repovoamento com animais livres. Esta última estratégia, nas condições desse trabalho, mostrou-se a mais eficaz, pois erradicou a DA.

This study aimed to evaluate strategies for eradication of Aujeszky Disease (AD) virus infection after outbreaks in swine production systems in Sao Paulo state. Two outbreaks were identified in Cerqueira César county. The first outbreak coursed with seropositive pigs (outbreak 1), and the other with pigs presenting clinical signs (outbreak 2). In order to eradicate the infection, two sanitary strategies were tested: (1) eradication of animals with positive serology and (2) by gradual depopulation, with a follow up of 12 months. The serology eradication was used in outbreak 1, and included the identification, isolation and slaughter of positive animals; followed by vaccination of negative animals and replacement with pigs from farms free of the disease. At the beginning, 68% of pigs were positive, and at the end it declined to 51%. In outbreak 2, gradual depopulation was used, and all animals were sent to sanitary slaughter, until facilities were completely empty. Afterwards, animals free of the disease were used for repopulation. It was seen that the last strategy was more effective because eradicated the infection.

Ocorrência de animais persistentemente infectados pelo vírus da diarréia viral bovina em rebanhos bovinos nos Estados de Minas Gerais e São Paulo / Occurrence of persistently infected animals with bovine viral diarrhoea virus in cattle herds from the States of Minas Gerais and São Paulo, Brazil

A pesquisa de animais persistentemente infectados (PI) pelo vírus da diarréia viral bovina (BVDV) foi realizada em 26 rebanhos bovinos, não vacinados contra o BVDV, localizados nos Estados de Minas Gerais e São Paulo, Brasil. Utilizando uma estratégia de amostragem, de cada rebanho foram obtidas cinco amostras de sangue de bezerros, entre 6 e 12 meses de idade, e os soros sanguíneos foram submetidos ao teste de virusneutralização (VN) para o BVDV-1 e o BVDV-2. Os rebanhos que apresentaram pelo menos três das cinco amostras reagentes a um dos genótipos do BVDV, e com títulos de anticorpos superiores a 128, foram selecionados para a pesquisa de animais PI. Em três rebanhos que apresentaram tal condição, foram colhidas amostras pareadas de sangue de todos os bovinos do rebanho, com intervalo de 30 dias entre as colheitas, e o soro sanguíneo foi submetido ao teste de VN para o BVDV-1 e o BVDV-2. Nas amostras não reagentes a pelo menos um dos genótipos do BVDV e naquelas provenientes de bovinos com menos de seis meses de idade, realizou-se a pesquisa do BVDV pela reação em cadeia da polimerase precedida pela transcrição reversa (RT-PCR). Dos rebanhos analisados, foram detectados dois animais PI a partir de amostras obtidas nas colheitas pareadas provenientes de um rebanho localizado no Estado de Minas Gerais.

The research on persistently infected (PI) animals with bovine viral diarrhoea virus (BVDV) was conducted in 26 cattle herds, which were not BVDV vaccinated, located in the states of Minas Gerais and São Paulo, Brazil. Using a sampling strategy, five samples of blood were collected from 6 to 12-month-old calves of each herd, and the blood sera were tested by virusneutralization test (VN) to BVDV-1 and BVDV-2. The herds that had at least three out of five samples reacting to one of the genotypes of BVDV and antibody titers greater than 128 were selected to PI animals research. In three of the herds that matched the before-mentioned criteria, paired blood samples were collected from all its individuals considering a collection interval of 30 days. The blood sera of these samples were VN tested against BVDV-1 and BVDV-2. In samples not reacting to at least one of the BVDV genotypes and also in those collected from calves of less than six months of age, virus research was undertaken by reverse transcription polymerase chain reaction (RT-PCR). From the examined herds, two PI animals were detected in paired samples obtained from a herd located in the state of Minas Gerais.

Geographical distribution of vampire bat-related cattle rabies in Brazil.

Seventy-seven rabies virus (RV) isolates originating from Brazilian cattle were genetically characterized. Partial nucleoprotein gene sequences of these isolates were phylogenetically and geographically analyzed. Cattle isolates, which clustered with the vampire bat-related RV group, were further subdivided into nine genetic subgroups. These subgroups were distributed widely in lowland regions, with some subgroups separated from each other by mountain ranges. In addition, separation of the groups in mountainous regions was correlated with altitude. These results indicate that cattle rabies is derived from several regionally-defined variants, which suggests that its geographical distribution is related to that of the vampire bat population.

Molecular epidemiological analysis of bat rabies viruses in Brazil.

A molecular epidemiological analysis was performed in 19 rabies viruses (RVs) isolated from haematophagous, frugivorous and insectivorous bats, in Sao Paulo, Brazil. The authors carried out RT-PCR for amplification of the RV nucleoprotein (N) gene, and determined 1,335 nucleotide sequences of N gene by direct sequencing method. Phylogenetic analysis, which was based on the N gene of Brazilian RV isolates identified presently and previously, revealed that RVs isolated from bats were genetically divided into four lineages had a tendency to depend on the host bat species. The first lineage consisted mainly of haematophagous bat (Desmodus rotundus) isolates, including frugivorous bat (Artibeus spp.) isolates. Other three lineages consisted of insectivorous bat isolates; mainly Eptesicus spp., Molossus spp. and Nyctinomops spp. isolates, respectively. These results indicate a possibility of that there are bat species-specific RV variants in Brazil.

Genetic characterization of rabies viruses isolated from frugivorous bat (Artibeus spp.) in Brazil.

In Latin America, rabies cases related to frugivorous bats have been reported since 1930's. Recently, two viruses isolated from Artibeus lituratus were proved to be vampire bat variants by monoclonal antibodies panels [2], but their genetic information is not well known. In this report, four rabies viruses were isolated from frugivorous bats (Artibeus spp.) in Brazil and their nucleoprotein gene sequences were determined. These isolates were found to be genotype 1 of lyssavirus and showed the maximum nucleotide sequence homology of 97.6-99.4% with vampire bat-related viruses in Brazil [6]. These results indicate that the Brazilian frugivorous bat rabies viruses in this study are closely related to vampire bat-related viruses that play a main role in rabies virus transmission to livestock in Brazil.

Genetic and phylogenetic analysis of glycoprotein of rabies virus isolated from several species in Brazil.

Genetic and phylogenetic analyses of the region containing the glycoprotein (G) gene, which is related to pathogenicity and antigenicity, and the G-L intergenic region were carried out in 14 Brazilian rabies virus isolates. The isolates were classified as dog-related rabies virus (DRRV) or vampire bat-related rabies virus (VRRV), by nucleoprotein (N) analysis. The nucleotide and amino acid (AA) homologies of the area containing the G protein gene and G-L intergenic region were generally lower than those of the ectodomain. In both regions, nucleotide and deduced AA homologies were lower among VRRVs than among DRRVs. There were AA differences between DRRV and VRRV at 3 antigenic sites and epitopes (IIa, WB+ and III), suggesting that DRRV and VRRV can be distinguished by differences of antigenicity. In a comparison of phylogenetic trees between the ectodomain and the area containing the G protein gene and G-L intergenic region, the branching patterns of the chiropteran and carnivoran rabies virus groups differed, whereas there were clear similarities in patterns within the DRRV and VRRV groups. Additionally, the VRRV isolates were more closely related to chiropteran strains isolated from Latin America than to Brazilian DRRV. These results indicate that Brazilian rabies virus isolates can be classified as DRRV or VRRV by analysis of the G gene and the G-L intergenic region, as well as by N gene analysis.