Artificial insemination of gilts with bovine viral diarrhea virus-contaminated semen

Bovine viral diarrhea virus (BVDV) is a pestivirus that infects swine and other species and has genetic and antigenic similarity to classical swine fever virus. The objective of this study was to mimic the infection of swine by contaminated semen and evaluate the effects on their reproductive tracts and litters. Six gilts were artificially inseminated with semen containing BVDV-2 ncp (LVB 16557/15) and 2 were inseminated with BVDV-free semen. Blood samples from all gilts were collected for polymerase chain reaction and virus neutralization tests. No viremia or neutralizing antibodies were detected, and all the litters were born healthy.

The history of foot-and-mouth disease virus serotype C: the first known extinct serotype?

Foot-and-mouth disease (FMD) is a highly contagious animal disease caused by an RNA virus subdivided into seven serotypes that are unevenly distributed in Asia, Africa, and South America. Despite the challenges of controlling FMD, since 1996 there have been only two outbreaks attributed to serotype C, in Brazil and in Kenya, in 2004. This article describes the historical distribution and origins of serotype C and its disappearance. The serotype was first described in Europe in the 1920s, where it mainly affected pigs and cattle but as a less common cause of outbreaks than serotypes O and A. No serotype C outbreaks have been reported in Europe since vaccination stopped in 1990. FMD virus is presumed to have been introduced into South America from Europe in the nineteenth century, although whether serotype C evolved there or in Europe is not known. As in Europe, this serotype was less widely distributed and caused fewer outbreaks than serotypes O and A. Since 1994, serotype C had not been reported from South America until four small outbreaks were detected in the Amazon region in 2004. Elsewhere, serotype C was introduced to Asia, in the 1950s to the 1970s, persisting and evolving for several decades in the Indian subcontinent and for eighteen years in the Philippines. Serotype C virus also circulated in East Africa between 1957 and 2004. Many serotype C viruses from European and Kenyan outbreaks were closely related to vaccine strains, including the most recently recovered Kenyan isolate from 2004. International surveillance has not confirmed any serotype C cases, worldwide, for over 15 years, despite more than 2,000 clinical submissions per year to reference laboratories. Serology provides limited evidence for absence of this serotype, as unequivocal interpretation is hampered by incomplete intra-serotype specificity of immunoassays and the continued use of this serotype in vaccines. It is recommended to continue strengthening surveillance in regions of FMD endemicity, to stop vaccination against serotype C and to reduce working with the virus in laboratories, since inadvertent escape of virus during such activities is now the biggest risk for its reappearance in the field.

Prevalence and risk factors for bluetongue in the State of São Paulo, Brazil

Bluetongue (BT), caused by Bluetongue virus (BTV), is a disease that affects ruminants such as cattle, sheep, goats and deer. BTV is transmitted by female midges of the genus Culicoides. In Brazil, information on the prevalence of BTV in cattle is limited, so the objective of this work was to identify BTV serotypes in cattle. The State of São Paulo was divided into seven cattle‐producing regions, and in each of them, 300 cattle farms were randomly selected. One animal from each farm (out of a total of 1,598 farms) was selected and its sera tested by virus neutralization technique against BTV serotypes (1–24 and 26) for determining antibody titre. Moreover, for each sampled farm, an epidemiological questionnaire was submitted to verify the type of cattle production and the zootechnical and sanitary practices carried out, which could be associated with a higher risk of BTV infection. In this study, antibodies (percentage, [95% confidence interval]) were identified against 11 serotypes: BTV‐1 (22.15%, [15.72–27.92]), BTV‐2 (31.03%, [26.65–37.98]), BTV‐3 (18.96%, [12.42–24.90]), BTV‐4 (24.90% [19.41–29.12]), BTV‐9 (6.82%, [1.45–11.72]), BTV‐12 (7.50%, [2.82–12.51]), BTV‐17 (23.90%, [17.35–29.35]), BTV‐19 (10.20%, [4.62–5.56]), BTV‐21 (30.66%, [25.00–36.00]), BTV‐22 (12.14%, [5.91–18.55]), BTV‐26 (57.00%, [51.41–63.59]). In this study, for the first time in Brazil serological evidence of the presence of serotypes BTV‐2, BTV‐9, BTV‐21 and BTV‐26 is reported. The variable ‘new cattle entering herd’ was considered a risk factor for the occurrence of infection (OR = 2.183, 95% CI = 1.6–2.9).

Genetic diversity of BCoV in Brazilian cattle herds

Bovine coronavirus (BCoV) is one of the main aetiological agents of gastroenteritis in calves, causing significant economic damage to livestock. This study aims to characterise BCoV genetically on the basis of the N gene. A total of 114 faecal samples from beef and dairy calves with or without clinical symptoms of diarrhoea from five Brazilian states (São Paulo, Minas Gerais, Santa Catarina, Mato Grosso and Bahia) were evaluated between 2008 and 2015 by technique of Semi-nested RT-PCR for gene N and genealogical analysis. Of the 114 samples analysed, 14.91% (17/114) were positive. BCoV was detected in 22.72% (10/44) of the animals with diarrhoea and in 10% (7/70) of asymptomatic animals. BCoV was identified in calves from rural properties located in all of the regions sampled. Genealogical analysis showed that the Brazilian sequences of BCoV for the gene which codes for the N protein can be broken down into two distinct clusters, and the samples from this study were closely linked to Asian strains. These results contribute to the molecular characterization of BCoV in Brazil and are the first report of the circulation of BCoV in the states of Santa Catarina and Bahia.

Serological investigation of antibodies against respiratory viruses in calves from Brazilian family farming and their relation to clinical signs of bovine respiratory disease

ABSTRACT: Bovine respiratory disease (BRD) is responsible for economic losses in cattle production. Viruses are categorized as primary etiological agents. The aims of this study were to evaluate the presence of antibodies against bovine viral diarrhea virus (BVDV), bovine herpes virus type 1 (BoHV-1), and bovine respiratory syncytial virus (BRSV) in healthy and BRD calves from family farming in relation to clinical signs of BRD. Hundred and forty-five calves were randomly selected and physical examination was performed. Only 123 animals were classified as healthy and BRD calves. Antibodies were evaluated by virus neutralization test. Person’s Chi-square test and Fisher’s exact test were performed as univariate analysis. Binary Logistic Regression was applied as multivariate analysis. Variables with P<0.10 were considered statistically significant. Variables with 0.15<P<0.10 were considered as statistical tendencies. Antibodies against BoHV-1, BVDV, and BRSV were detected in 32%, 23% and 37% animals. Antibodies against both three viruses were detected in 26.8% of calves. The presence of antibodies against BRSV were associated to normal heart rates (P=0.018) and unilateral airflow (P=0.035). Tendency was observed to unilateral airflow (P=0.06) Statistical tendencies were observed to Ab-BoHV-1 and body temperature (P=0.119) and breathing pattern (P=0.123). The profile of antibodies against respiratory viruses in calves from Brazilian family farming was firstly described. The results confirmed the importance of some clinical signs to viral infection.

Detection and genetic identification of pestiviruses in Brazilian lots of fetal bovine serum collected from 2006 to 2014

ABSTRACT: The present study performed a genetic identification of pestiviruses contaminating batches of fetal bovine serum (FBS) produced in Brazil from 2006 to 2014. Seventy-three FBS lots were screened by a RT-PCR targeting the 5’untranslated region (UTR) of the pestivirus genome. Thirty-nine lots (53.4%) were positive for pestivirus RNA and one contained infectious virus. Nucleotide sequencing and phylogenetic analysis of the 5’UTR revealed 34 lots (46.6%) containing RNA of bovine viral diarrhea virus type 1 (BVDV-1), being 23 BVDV-1a (5’ UTR identity 90.8-98.7%), eight BVDV-1b (93.9-96.7%) and three BVDV-1d (96.2- 97.6%). Six lots (8.2%) contained BVDV-2 (90.3-100% UTR identity) being two BVDV-2a; three BVDV-2b and one undetermined. Four FBS batches (5.5%) were found contaminated with HoBi-like virus (98.3 to 100%). Five batches (6.8%) contained more than one pestivirus. The high frequency of contamination of FBS with pestivirus RNA reinforce the need for systematic and updated guidelines for monitoring this product to reduce the risk of contamination of biologicals and introduction of contaminating agents into free areas.

Effects of oocytes exposure to bovine diarrhea viruses BVDV-1, BVDV-2 and Hobi-like virus on in vitro-produced bovine embryo development and viral infection

As production of in vitro (IVP) bovine embryos steadily increases, the sanitary risk associated with IVP embryos remains a concern. One of the greatest concerns is how BVDV may be transmitted through IVP embryos. The objective of this study was to evaluate the effects caused by BVDV-1, BVDV-2 and Hobi-like virus exposure during in vitro maturation on embryo development and viral infection. Abittior-derived oocytes were randomly assigned for in vitro maturation with serial concentrations of BVDV-1 (3.12 × 10² - 2.50 × 10³ TCID₅₀/100 μL), BVDV-2 (6.25 × 10¹ - 5.20 × 10² TCID₅₀/100 μL) or Hobi-like virus (1.90 × 10² - 1.58 × 10³ TCID₅₀/100 μL) for 22-24 h. After maturation, oocytes were fertilized and embryo cultured following standard in vitro procedures. Embryo development was evaluated and percentage of respective, positive BVDV degenerated and viable embryos were evaluated by RT-qPCR. No concentration of BVDV-1 altered embryo development as measured by cleavage and blastocyst rates, compared to negative control group. However 100% of degenerated embryos and 50-100% of viable embryos tested positive for BVDV-1, depending on the viral concentration. BVDV-2 exposed oocytes had higher cleavage rates than the negative control group (60.2-64.1% vs 49.8%; P = 0.003-0.032). However, no difference was detected for blastocyst rates. In aadition, 100% of degenerated embryos and 20-50% of viable embryos tested positive for BVDV-2. Hobi-like virus treated oocytes had reduced cleavage rates for the three highest viral concentrations (33.3-38.0% vs 49.8% for negative controls; P ≤ 0.001-0.014). Blastocyst rates were only reduced in the 7.9 × 10² Hobi-like virus concentration (6.9 ± 0.9% vs 15.1 ± 1.6%; P = 0.009), when calculated by oocyte number. 50-80% of degenerated embryos tested positive for Hobi-like virus. No viable embryos from the Hobi-like virus treated oocytes tested positive. These results suggest that IVP embryos from BVDV-1 and -2 infected oocytes develop normally, but carry the virus. However, Hobi-like virus infected oocytes had reduced cleavage and cause pre-implantation embryo loss, but viable embryos did not carry the virus.

Malignant Catarrhal Fever in Brazilian cattle presenting with neurological syndrome

Malignant Catarrhal Fever (MCF) was investigated in the central nervous system of cattle with neurological syndrome. Two-hundred-ninety samples were analyzed by histology, and molecular methods to detect ovine herpesvirus type 2 (OvHV-2) were optimized and validated. The qualitative polymerase chain reaction (qualitative PCR) analytical sensitivity was 10¹ DNA copies/μL and found 4.8% (14/290) positive for OvHV-2. The quantitative polymerase chain reaction (qPCR) analytical sensitivity was 10⁰ DNA copy/μL and 5.9% (17/290) positivity, with 47.1% (8/17) of the positive samples presenting histological evidence of non-purulent meningo-encephalitis. The qualitative PCR products (422 bp of the ORF75 region) were sequenced and submitted to phylogenetic analysis. Identity matrices showed 100% similarity in OvHV-2 samples obtained in this study and those recovered from GenBank, corroborating other studies.

Serological evidence and risk factors associated with Caprine herpesvirus 1 in dairy goat flocks in a semiarid region of northeastern Brazil

A cross-sectional study was carried out to determine the flock-level seroprevalence of Caprine herpesvirus 1 (CpHV-1) and Bovine herpesvirus 1 (BoHV-1) and 2 (BoHV-2) and risk factors associated with CpHV-1 in dairy goat flocks from a semiarid region of northeastern Brazil. A total of 1,034 serum samples from 110 flocks were collected from March 2009 through March 2010. A structured questionnaire focusing on variables related to risk factors for CpHV-1 infection was given to each farmer at the time of blood collection. Antibodies against CpHV-1, BoHV-1, and BoHV-2 were detected by neutralization tests. The flock-level prevalences of CpHV-1, BoHV-1, and BoHV-2 were 89.1% (98/110; 95% confidence interval [CI]: 81.7-94.2), 80% (88/110; 95% CI: 71.3-87), and 4.5% (5/110; 95% CI: 1.5-10.3), respectively. Frequencies of seropositive animals were 36.6% (379/1,034), 25.8% (267/1,034), and 0.6% (6/1,034) for CpHV-1, BoHV-1, and BoHV-2, respectively. The use of natural mating was identified as a risk factor associated with CpHV-1 flock-level prevalence (P = 0.001). It is suggested that adoption of veterinary services and active surveillance of the at-risk flocks in the study region should be initiated to reduce the prevalence of herpesvirus infections.

Simultaneous presence of bovine papillomavirus and bovine leukemia virus in different bovine tissues: in situ hybridization and cytogenetic analysis

Bovine papillomavirus (BPV) DNA sequences were detected in different tissues, in addition to epithelium. Cytogenetic abnormalities were observed in blood lymphocytes. The presence of more than one virus in a single tissue is a difficult aspect to evaluate, especially when the DNA sequences are detected in tissues that are not specifically targeted by the virus. BPV and bovine leukemia virus (BLV) are clastogenic, causing chromosome aberrations in peripheral blood lymphocytes. In the present study, we investigated the simultaneous presence of DNA sequences of both viruses and the possibility of vertical transmission and compared the types of chromosome aberrations related to viral action. BPV 1, 2, and 4 DNA sequences were found in three females of the herd and in their offspring. BLV DNA sequences were not detected in their progeny. A newborn calf that was negative for BLV infection showed specific chromosome rearrangements possibly related to the effect of infection with BPV.

Ocorrência de anticorpos anti-Neospora caninum em cães da microrregião da Serra de Botucatu, Estado de São Paulo, Brasil

Neosporose é uma enfermidade parasitária causada pelo protozoário Neospora caninum reconhecido como importante causa de abortamento bovino e neuropatia canina. Considerando o isolamento de N. caninum e a sorologia freqüente em bovinos em nossa região, os objetivos do presente trabalho foram avaliar a ocorrência de anticorpos anti-N. caninum em cães da Microrregião da Serra de Botucatu, Estado de SãoPaulo, e sua associação ao sexo, idade e procedência quanto à zona urbana (exclusivamente cidade), rural (somente chácaras e sítios) e peri-urbana (acesso à zona urbana e rural) dos cães estudados. Foram analisados 963 cães, com ou sem raça definida, de ambos os sexos e diferentes idades, sem apresentação de qualquer sintomatologia clínica. Os animais foram selecionados aleatoriamente durante a campanha de vacinação anti-rábica da microrregião da Serra de Botucatu, no período de maio a setembro de 1998. O soro obtido dos animais foi avaliado por meio da Reação de Imunofluorescência Indireta (RIFI) utilizando como antígeno a cepa padrão NC-1 deN. caninum. Observaram-se 245 animais reagentes (25,4% de positividade), sendo 161 (27,5%) machos e, 84 (22,3%) fêmeas. Dos animais de zona urbana, rural e mista 223 (25,8%),11(16,9%) e 11(33,3%), respectivamente, foram reagentes à prova de RIFI. Todos os 11 municípios apresentaram cães soropositivos com valores de ocorrência que variaram de 8,9% a 53,5%. Observou-se percentual de positividade menor em cães até um ano (16,2%) quando comparados àqueles entre 1 a 4 anos e superior a 4 anos (28,4 % e 28,0%, respectivamente) que não apresentaram diferença entre si. Os resultados obtidos caracterizaram soropositividade para N. caninum em cães pertencentes a todos os municípios da Microrregião da Serra de Botucatu evidenciando a ampla distribuição do agente na região.

A infecção pelo vírus da diarréia viral bovina (BVDV) no Brasil: histórico, situação atual e perspectivas

O vírus da Diarréia Viral Bovina (BVDV) possui distribuição mundial e é considerado um dos principais patógenos de bovinos. A infecção e as enfermidades associadas ao BVDV têm sido descritas no Brasil desde os anos 60. Diversos relatos sorológicos, clínico-patológicos e de isolamento do agente demonstram a ampla disseminação da infecção no rebanho bovino brasileiro. Além de sorologia positiva em níveis variáveis em bovinos de corte e leite, anticorpos contra o BVDV têm sido ocasionalmente detectados em suínos, javalis, caprinos, cervos e bubalinos. O BVDV tem sido freqüentemente detectado em fetos abortados, na capa flogística de animais persistentemente infectados (PI) oriundos de rebanhos com problemas reprodutivos, em amostras clínicas e/ou material de necropsia de animais com as mais diversas manifestações clínicas, em sêmen de touros de centrais de inseminação artificial, em fetos saudáveis coletados em matadouros e em soro bovino comercial e/ou cultivos celulares. Aproximadamente 50 isolados do vírus já foram caracterizados genética e/ou antigenicamente, enquanto um número semelhante de amostras aguarda caracterização. A maioria dos isolados caracterizados pertence ao genótipo BVDV-1, biotipo não-citopático (NCP), embora vários isolados de BVDV-2 (e alguns BVDV citopáticos CP) já tenham sido identificados. Os isolados brasileiros apresentam grande variabilidade antigênica, além de diferenças antigênicas marcantes quando comparados a cepas vacinais norte-americanas. Algumas vacinas polivalentes (BHV-1, PI-3, BRSV), contendo o BVDV inativado, têm sido utilizadas no rebanho brasileiro. No entanto, o uso de vacinação ainda é incipiente na maioria das regiões; apenas 2,5 milhões de doses foram comercializadas em 2003. A baixa reatividade sorológica cruzada entre os isolados brasileiros e as cepas vacinais tem estimulado laboratórios nacionais a desenvolver vacinas com isolados autóctones de BVDV-1 e 2. O conhecimento sobre a infecção pelo BVDV no Brasil tem aumentado consideravelmente nos últimos anos, à medida em que cresce o número de laboratórios envolvidos em diagnóstico e pesquisa sobre esse vírus. Diagnóstico sorológico, virológico ou molecular; estudos sobre epidemiologia sorológica e molecular, patogenia e produção de reagentes para diagnósitco têm contribuído para o aumento no conhecimento sobre a infecção pelo BVDV no país.

Proteção fetal frente a desafio com o vírus da Diarréia Viral Bovina (BVDV) em ovelhas imunizadas com duas amostras de vírus modificadas experimentalmente

Duas amostras do vírus da Diarréia Viral Bovina (BVDV) submetidas a múltiplas passagens em cultivo celular e exposição à radiação ultravioleta (UV) a cada passagem foram avaliadas como candidatos a vírus vacinais. As amostras foram testadas quanto à sua atenuação para bezerros e fetos ovinos, reatividade antigênica contra isolados de campo, e capacidade de induzir proteção fetal em ovelhas prenhes. Inoculação intramuscular (IM) dos vírus modificados em quatro bezerros produziu apenas uma elevação discreta e passageira da temperatura corporal, seguida de produção de altos títulos de anticorpos neutralizantes. O vírus não foi detectado em secreções nasais ou sangue nos dias seguintes à inoculação. Porém, a inoculação IM desses vírus em quatro ovelhas prenhes foi seguida de transmissão transplacentária e infecção em todos os fetos. Para os testes de proteção fetal, ovelhas prenhes previamente imunizadas com duas doses vacinais, foram inoculadas por via intranasal com amostras de BVDV-1 (SV-126.8, n=6) ou BVDV-2 (SV-260, n=5). No dia do desafio (134 dias após a segunda dose), todos os animais apresentavam altos títulos de anticorpos neutralizantes (256 a >4096) contra os vírus vacinais; além de títulos variados (8 a >4096) contra várias isolados brasileiros de BVDV-1 e BVDV-2. Quinze dias após o desafio, as ovelhas foram sacrificadas e os tecidos fetais foram examinados para a presença de vírus. Todos os fetos das ovelhas controle não-vacinadas apresentaram-se (n=4) positivos para os vírus utilizados no desafio. Em contraste, nenhum feto das ovelhas imunizadas (n=11) foi positivo para vírus, indicando que a resposta imunológica induzida pela vacinação com os vírus modificados foi capaz de prevenir a infecção fetal. Estes resultados indicam que é possível obter-se forte resposta imunológica e proteção fetal contra o BVDV com o uso de vacinas vivas modificadas.