Avaliação da transmissão pela lâmina d’água do vírus da diarreia viral bovina em leitões desmamados experimentalmente infectados
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Data
2017-02-09
Autores
Nascimento, Karla Alvarenga [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os pestivírus possuem importância significativa na suinocultura, sendo que os suínos podem ser infectados pelo Vírus da Diarreia Viral Bovina (BVDV) em condições naturais. O presente estudo teve como objetivo induzir a infecção experimental do BVDV-1 em leitões desmamados e avaliar a excreção e possível transmissão do vírus pelas vias lâmina d’água e naso-nasal. Foram conduzidos dois experimentos e uma repetição para cada via de transmissão avaliada. No total foram selecionados 24 leitões, sendo utilizados seis por experimento, divididos em grupos controle (n=2), sentinela (n=2) e infectado (n=2), utilizando isoladores, projetados para estabelecer o contato entre os animais apenas pela via de transmissão em estudo. O grupo infectado recebeu um inóculo contendo BVDV-1, estirpe Singer, enquanto que os grupos controle e sentinela foram inoculados com meio E-MEM. Os animais permaneceram nos isoladores por 25 dias, período em que foram coletadas amostras de suabe nasal diariamente e sangue a cada sete dias. Ao final, os animais foram eutanasiados e necropsiados, sendo realizada coleta de fragmentos de órgãos para histopatologia, imunohistoquímica e RT-PCR. Quando avaliada a via de transmissão lâmina d’água, apenas um animal infectado apresentou excreção de material genômico a partir do 6o dia pós-infecção (dpi), e um animal sentinela apresentou excreção no 20o dpi. Nestes animais, a soroconversão ocorreu no 25o dia apresentando título de anticorpos igual a 20. Um animal infectado não apresentou soroconversão durante o período amostrado, porém houve excreção a partir do 5o dpi. Na repetição do experimento, apenas um animal infectado soroconverteu ao 25o dia, com título de anticorpos de 20, cuja excreção do material genômico foi detectada ao 21o dpi. Nos animais sentinelas, apenas um apresentou excreção no 13o dpi. Em relação ao experimento naso-nasal, os animais infectados apresentaram excreção de material genético a partir do 17o dpi, porém a soroconversão não foi observada em todos os animais. Na repetição do experimento naso-nasal a soroconversão foi detectada em apenas um dos leitões infectados no último dia de experimento, com título de anticorpos de 20. A excreção do material genômico ocorreu nos dois animais infectados, sendo que um animal apresentou excreção a partir do dia 10 e o outro a partir do 18o dpi. Em relação à macroscopia e microscopia, os animais de todos os experimentos não apresentaram lesões significativas. O presente estudo demonstra que os suínos são susceptíveis ao BVDV, possibilitando a excreção e servir como fonte de infecção. Evidenciou-se que a lâmina d’agua pode veicular o BVDV de um suíno infectado para outro, ressaltando a importância e o risco de transmissão. A possibilidade de transmissão do BVDV pela via naso-nasal em leitões não foi provada dentro do período avaliado.
Pestiviruses have significant importance in swine breeding, and pigs can be infected by Bovine Viral Diarrhea Virus (BVDV) under natural conditions. The present study aimed to induce the experimental infection of BVDV-1 in weaned piglets and to evaluate the excretion and possible transmission of the virus through the water and naso-nasal routes. Two experiments and one replicate were conducted for each evaluated route of transmission. In total, 24 piglets were selected, and six were used per experiment, divided into control (n = 2), sentinel (n = 2) and infected (n = 2) groups using isolators, designed to establish contact between animals only by Route of study. The infected group received an inoculum containing BVDV-1, Singer strain, while the control and sentinel groups were inoculated with E-MEM medium. The animals remained in the isolators for 25 days, during which samples of nasal swab and blood were collected every seven days. At the end, the animals were euthanized and necropsied, and organ fragments were collected for histopathology, immunohistochemistry and RT-PCR. When the water-borne transmission pathway was evaluated, only one infected animal showed excretion of genomic material from day 6 post-infection (dpi), and one sentinel animal showed excretion at the 20th dpi. In these animals, seroconversion occurred on day 25 with an antibody titer equal to 20. An infected animal did not present seroconversion during the sampled period, but there was excretion from the 5th dpi. In the repeat of the experiment, only one infected animal was seroconverted at day 25, with antibody titer of 20, whose excretion of the genomic material was detected at 21o dpi. In sentinel animals, only one had excretion at the 13th dpi. In relation to the naso-nasal experiment, the infected animals presented excretion of genetic material from the 17th dpi, but seroconversion was not observed in all the animals. In the repetition of the nasonasal experiment, seroconversion was detected in only one of the infected piglets on the last day of the experiment, with an antibody titre of 20. Excretion of the genomic material occurred in the two infected animals, and one animal had excretion from the Day 10 and the other from the 18th dpi. Regarding macroscopy and microscopy, the animals of all experiments did not present significant lesions. The present study demonstrates that pigs are susceptible to BVDV, allowing excretion and serve as a source of infection. It has been shown that the water table can transport BVDV from one infected pig to another, emphasizing the importance and risk of transmission. The possibility of BVDV transmission by the nasal nasal route in piglets has not been proven within the evaluated period.
Pestiviruses have significant importance in swine breeding, and pigs can be infected by Bovine Viral Diarrhea Virus (BVDV) under natural conditions. The present study aimed to induce the experimental infection of BVDV-1 in weaned piglets and to evaluate the excretion and possible transmission of the virus through the water and naso-nasal routes. Two experiments and one replicate were conducted for each evaluated route of transmission. In total, 24 piglets were selected, and six were used per experiment, divided into control (n = 2), sentinel (n = 2) and infected (n = 2) groups using isolators, designed to establish contact between animals only by Route of study. The infected group received an inoculum containing BVDV-1, Singer strain, while the control and sentinel groups were inoculated with E-MEM medium. The animals remained in the isolators for 25 days, during which samples of nasal swab and blood were collected every seven days. At the end, the animals were euthanized and necropsied, and organ fragments were collected for histopathology, immunohistochemistry and RT-PCR. When the water-borne transmission pathway was evaluated, only one infected animal showed excretion of genomic material from day 6 post-infection (dpi), and one sentinel animal showed excretion at the 20th dpi. In these animals, seroconversion occurred on day 25 with an antibody titer equal to 20. An infected animal did not present seroconversion during the sampled period, but there was excretion from the 5th dpi. In the repeat of the experiment, only one infected animal was seroconverted at day 25, with antibody titer of 20, whose excretion of the genomic material was detected at 21o dpi. In sentinel animals, only one had excretion at the 13th dpi. In relation to the naso-nasal experiment, the infected animals presented excretion of genetic material from the 17th dpi, but seroconversion was not observed in all the animals. In the repetition of the nasonasal experiment, seroconversion was detected in only one of the infected piglets on the last day of the experiment, with an antibody titre of 20. Excretion of the genomic material occurred in the two infected animals, and one animal had excretion from the Day 10 and the other from the 18th dpi. Regarding macroscopy and microscopy, the animals of all experiments did not present significant lesions. The present study demonstrates that pigs are susceptible to BVDV, allowing excretion and serve as a source of infection. It has been shown that the water table can transport BVDV from one infected pig to another, emphasizing the importance and risk of transmission. The possibility of BVDV transmission by the nasal nasal route in piglets has not been proven within the evaluated period.
Descrição
Palavras-chave
BVDV, Isoladores, RT-PCR, Via de transmissão, Virusneutralização