Excreção e transmissão do vírus da diarréia viral bovina por bezerros persistentemente infectados

Arenhart, Sandra; Bauermann, Fernando V.; Oliveira, Stephan Alberto Machado de; Weiblen, Rudi; Flores, Eduardo Furtado

doi:10.1590/s0100-736x2009000900010

Cited by 11 publications

(7 citation statements)

References 19 publications

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“…While the abortion and the death of two newborns cannot be unequivocally ascribed to HoBi-like virus infection, these events are consistent with clinical presentations classically observed with other pestiviruses (1). Although multiple positive tests over time were not possible, the presence of virus in multiple tissues and fluids of these three animals is consistent with persistent infection (1,9,10,23). The four remaining calves were confirmed to be persistently infected with HoBi-like viruses based on multiple detections over a period of several weeks.…”

Section: Discussionsupporting

confidence: 82%

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Generation of Calves Persistently Infected with HoBi-Like Pestivirus and Comparison of Methods for Detection of These Persistent Infections

et al. 2014

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The identification and elimination of persistently infected (PI) cattle are the most effective measures for controlling bovine pestiviruses, including bovine viral diarrhea virus (BVDV) and the emerging HoBi-like viruses. Here, colostrum-deprived calves persistently infected with HoBi-like pestivirus (HoBi-like PI calves) were generated and sampled (serum, buffy coat, and ear notches) on the day of birth (DOB) and weekly for 5 consecutive weeks. The samples were subjected to diagnostic tests for BVDV-two reverse transcriptase PCR (RT-PCR) assays, two commercial real-time RT quantitative PCR (RT-qPCR), two antigen capture enzyme-linked immunosorbent assays (ACE), and immunohistochemistry (IHC)-and to HoBi-like virus-specific RT-PCR and RT-qPCR assays. The rate of false negatives varied among the calves. The HoBi-like virus-specific RT-PCR detected HoBi-like virus in 83%, 75%, and 87% of the serum, buffy coat, and ear notch samples, respectively, while the HoBi-like RT-qPCR detected the virus in 83%, 96%, and 62%, respectively. In comparison, the BVDV RT-PCR test had a higher rate of false negatives in all tissue types, especially for the ear notch samples (missing detection in at least 68% of the samples). The commercial BVDV RT-qPCRs and IHC detected 100% of the ear notch samples as positive. While ACE based on the BVDV glycoprotein E rns detected infection in at least 87% of ear notches, no infections were detected using NS3-based ACE. The BVDV RT-qPCR, ACE, and IHC yielded higher levels of detection than the HoBi-like virus-specific assays, although the lack of differentiation between BVDV and HoBi-like viruses would make these tests of limited use for the control and/or surveillance of persistent HoBi-like virus infection. An improvement in HoBi-like virus tests is required before a reliable HoBi-like PI surveillance program can be designed.

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Section: Discussionsupporting

confidence: 82%

“…While some BVDV PI calves have congenital malformations, others are clinically normal (1,9). These animals shed the virus to the environment continuously over their lifetimes (1,10) and thus play a major role in introducing and maintaining viral circulation in cattle herds (11).…”

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confidence: 99%

Generation of Calves Persistently Infected with HoBi-Like Pestivirus and Comparison of Methods for Detection of These Persistent Infections

et al. 2014

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“…Periodic VN testing, as expected for passively acquired antibodies, resulted in gradual reduction of antibody titers and at day 210 none of the calves had detectable levels (<2) of VN antibodies (Table 1). Monitoring the infectivity in the sera of these calves up to day 150 revealed persistent viremia in variable levels (Arenhart et al 2009). …”

Section: Resultsmentioning

confidence: 97%

Evidence of mixed persistent infections in calves born to cows challenged with a pool of bovine viral diarrhea virus isolates

et al. 2010

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RESUMO.-[Evidências de infecção persistente mista em bezerros nascidos de vacas inoculadas com um pool de isolados do vírus da diarréia viral bovina.]Vacas prenhes infectadas com isolados não-citopáticos (NCP) do vírus da diarréia viral bovina (BVDV) entre os dias 40 e 120 de gestação frequentemente produzem bezerros imunotolerantes, persistentemente infectados (PI). Este artigo relata a caracterização de bezerros PI produzidos experimentalmente, pela inoculação de vacas prenhes com um pool de isolados brasileiros de BVDV-1 (n=2) e BVDV-2 (n=2) entre os dias 60 e 90 de gestação. Dois bezerros nasceram positivos para vírus, negativos para anticorpos, mas morreram aos dias 7 e 15 pós-nascimento, respectivamente. Pregnant cows infected with noncytopathic (NCP) isolates of bovine viral diarrhea virus (BVDV) between days 40 and 120 days of gestation frequently deliver immunotolerant, persistently infected (PI) calves. We herein report the characterization of PI calves produced experimentally through inoculation of pregnant cows with a pool of Brazilian BVDV-1 (n=2) and BVDV-2 isolates (n=2) between days 60 and 90 of gestation. Two calves were born virus positive, lacked BVDV antibodies, but died 7 and 15 days after birth, respectively. Six other calves were born healthy, seronegative to BVDV, harbored and shed virus in secretions for up to 210 days. Analysis of the antigenic profile of viruses infecting these calves at birth and 30 days later with a panel of monoclonal antibodies indicated two patterns of infection. Whereas three calves apparently harbored only one isolate (either a BVDV-1 or BVDV-2), co-infection by two antigenically distinct challenge viruses was demonstrated in three PI calves. Moreover, testing the viruses obtained from the blood of PI calves by an RT-PCR able to differentiate between BVDV-1 and BVDV-2 confirmed the presence/persistence of two co-infecting viruses of different genotypes (BVDV-1 and BVDV-2) in these animals. These findings indicate that persistent infection of fetuses/calves -a well characterized consequence of fetal infection by BVDV -may be established concomitantly by more than one isolate, upon experimental inoculation. In this sense, mixed persistent infections with antigenically distinct isolates may help in understanding the immunological and molecular basis of BVDV immunotolerance and persistence. ou BVDV-2), enquanto outros três bezerros apresentavam co-infecção com mais de um vírus. Além disso, testandose o sangue dos animais PI com um PCR capaz de diferenciar entre BVDV-1 e BVDV-2 observou-se a presença concomitante de vírus dos dois genótipos (BVDV-1 e BVDV-2) nestes três animais. Esses resultados indicam que infecção persistente -uma consequência bem conhecida da infecção fetal pelo BVDV -pode ser estabelecida concomitantemente por mais de um vírus, após infecção experimental. Nesse sentido, infecções persistentes mistas com isolados antigenicamente distintos podem ser úteis para o estudo das bases imunológicas e moleculares da imunotolerância e infecção persistente p...

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“…No presente trabalho, a alta porcentagem de bovinos soropositivos em rebanho não vacinado confirma a sua exposição ao BVDV, principalmente quando há presença de animal PI e sua identificação é tardia, o que favorece a disseminação do vírus, uma vez que há tempo da maioria dos animais entrarem em contato com o animal suspeito (Arenhart et al 2009). Esse percentual, de acordo com Houe & Meyling (1991), pode atingir até 87% dos bovinos expostos quando há um animal PI no rebanho.…”

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Detecção do virus ‘HoBi’-like (BVDV-3) em bovino no semiárido do Estado da Paraíba

et al. 2016

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RESUMO.-Objetivou-se descrever os aspectos clínicos e anatomopatológicos, e a identificação viral de um caso de infecção pelo vírus 'Hobi'-like (BVDV-3) em bovino do semiárido paraibano, Nordeste do Brasil. Um bovino, fêmea, três meses de idade, foi levado ao Hospital Veterinário da UFCG apresentando salivação, dificuldade de apreensão do teto, falta de apetite, fezes escuras e em pouca quantidade. Diante da piora do quadro clínico optou-se por sua eutaná-sia in extremis, seguida da realização da necropsia e coleta de material para histopatologia. Histologicamente, nas mucosas do trato digestivo, havia edema, degeneração balonosa, necrose e infiltrado inflamatório, que foi observado na face dorsal da língua e no seu epitélio mais profundo. The aim of this study was to describe the clinical and anatomopathological aspects, and the viral identification of a case of 'Hobi'-like (BVDV-3) vírus infection in cattle from the semiarid of Paraiba State, Northeastern Brazil. A female bovine, three months old, was sent to the UFCG's Veterinary Hospital presenting salivation, difficulty of ceiling seizure, lack of appetite, dark feces and in small amounts. Due to worsening of symptoms it was decided to in extremis euthanasia, followed by the necropsy and collection of material for histopathology. Histologically, in the mucous membranes of the digestive tract there were edema, ballooning degeneration, necrosis and inflammatory infiltrate, which was observed on the dorsal surface of the tongue and in its deepest epithelium. The immunohistochemical of skin biopsies of the extremity of the ear (ear notches) showed positive antigenic marking and by RT-PCR it was possible to detect viral RNA of BVDV in the serum, whose cytopathic effect in epithelial cells of bovine kidney lineage "Madin Darby bovine kidney" (MDBK)was not observed. The sequencing of the 5'NCR gene showed that the virus isolated was more related to 'Hobi'-like (BVDV-3). After confirming the diagnosis serum samples were collected from 23 animals for serology by indirect ELISA, and a seropositivity of 69.6% (16/23) was found. The identification of this new case of 'Hobi'-like infection in Paraiba reaffirms the need for regular BVDV monitoring in the region to early detection of infection in the herds and adoption of effective preventive and control measures.INDEX TERMS: Cattle, BVDV-3, pestivirus, viral identification.

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Excreção e transmissão do vírus da diarréia viral bovina por bezerros persistentemente infectados

Cited by 11 publications

References 19 publications

Generation of Calves Persistently Infected with HoBi-Like Pestivirus and Comparison of Methods for Detection of These Persistent Infections

Generation of Calves Persistently Infected with HoBi-Like Pestivirus and Comparison of Methods for Detection of These Persistent Infections

Evidence of mixed persistent infections in calves born to cows challenged with a pool of bovine viral diarrhea virus isolates

Detecção do virus ‘HoBi’-like (BVDV-3) em bovino no semiárido do Estado da Paraíba

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