Natural association between bovine leukemia virus and reproductive infectious diseases

Background: Enzootic bovine leukosis (EBL) is a widespread infectious disease caused by the bovine leukemia virus (BLV), which results in immune system dysfunction. The resulting immunosuppression may lead to an increased prevalence of other diseases. Dairy cows infected have altered immune function associated with decreased milk production and shortened lifespan and decreased immune response to immunization. BLV infection, however, is often asymptomatic, so any connection between subclinical infection and common reproductive diseases remains unknown. This study aimed to describe the relationship between naturally occurring subclinical BLV and infectious reproductive diseases seroconversion in the field. Materials, Methods & Results: The diseases investigated included Bovine viral diarrhoea (BVD), Bovine alfaherpesvirus 1 (BoHV-1), Bovine gammaherpesvirus 4 (BoHV-4), Chlamydiosis, Leptospirosis, Brucellosis and Neosporosis in dairy cattle. Six hundred fifty-five sera samples from the northern and south-central regions of Uruguay, from asymptomatic female Holstein and Holstein crosses without a history of vaccination against reproductive diseases were processed using reference diagnostic methods (Seronautalization, ELISA, MAT, Rose Bengal Plate test). The seroprevalence of BLV was 20.0%. Seroprevalence of reproductive diseases BVD, BoHV-1 and BoHV-4 were 99.3%, 41.2% and 27.3% of the populations, respectively, and the total seroprevalence of Leptospirosis, bovine Neospora caninum and Chlamydiosis were 19.8%, 29.8% and 33.0% respectively. The results revealed positive associations between naturally contracted BLV and the presence of antibodies against BoHV-1 (P = 0.002), as well as between naturally contracted BLV and presence of antibodies against Leptospira spp. (P = 0.028). Discussion: BLV infection can impact innate and adaptive immune system cells and alter the proper functioning of uninfected cells. BLV infection may also induce changes in the complex balance of cytokine expression, cell proliferation, and programmed cell death in T- and B-lymphocytes, which is critical for immune competence and effective response to infectious challenges. The progression of BLV infection has a substantial effect on host defense mechanisms. Indeed, lowmagnitude serologic responses to a commercial foot-and-mouth disease vaccine and a J5 Escherichia coli vaccine have been observed. These results are supported by recent trial studies showing a reduced immune response to vaccination against BoHV-1 and Leptospira spp. in asymptomatic animals infected with BLV. These are 2 of the most prevalent infectious reproductive diseases in cattle worldwide, and our results provide evidence that a link between BLV and susceptibility to these diseases may exist. Although there is evidence of the co-occurrence of these diseases, it remains unknown whether there is a direct or indirect effect of BLV on infertility, embryonic loss, or abortion. Another possibility is that natural infection with these reproductive pathogens (BoHV-1, Leptospira, or others) promotes BLV expression, negatively affecting the farms where these pathogens are endemic. Considering the high seroprevalence of BLV in dairy herds in North and South America where the infection is endemic, it was explored BLV's role as an immunosuppressant by quantifying its co-occurrence with diseases that affect reproductive performance in breeding herds. Future work should clarify the role of BLV and the co-occurring pathogens in causing infertility or abortions.

Seroprevalence and risk factors associated with bovine herpesvirus 1 in dairy herds of Colombia.

Background and Aim: Infectious bovine rhinotracheitis (IBR) is an infectious disease widely distributed globally and is considered the main cause of various reproductive and respiratory tract diseases in cattle and buffaloes. This study aimed to estimate seroprevalence and determine risk factors associated with the presentation of IBR in the municipality of Sotaquirá, Boyacá (Colombia). Materials and Methods: A descriptive cross-sectional study with simple random sampling was performed, and the sample size was 1,000 cattle. Blood samples were obtained by coccygeal venipuncture and processed through indirect enzyme-linked immunosorbent assay using the Synbiotics® kit (Zoetis, New Jersey, USA) with a sensitivity and specificity of 96% and 98%, respectively. Data were processed using the statistical program EpiInfo® (Centers for Disease Control and Prevention; Atlanta, Georgia). Results: A high seroprevalence of 57.5% was established. Seroprevalence was the highest in cattle >4 years of age (65.0% apparent seroprevalence [AS]; 67% true seroprevalence [TS]) and in the Holstein breed (65.5% AS; 67.8% TS). The breed and age of the animals were significantly associated with each other. The Holstein breed, age group >4 years, uncertified semen, and fetal death were established as risk factors for IBR. In comparison, the age groups of <1 and 1-2 years and the Normande breed were established as protective factors against the bovine herpesvirus-1 virus. Conclusion: Management factors, such as livestock from other owners and animal purchases, which affect disease presentation, are evident. The implementation and development of novel prevention and control measures for IBR at the national level are necessary.

Use of pooled serum samples to assess herd disease status using commercially available ELISAs.

Pooled samples are used in veterinary and human medicine as a cost-effective approach to monitor disease prevalence. Nonetheless, there is limited information on the effect of pooling on test performance, and research is required to determine the appropriate number of samples which can be pooled. Therefore, this study aimed to evaluate the use of pooled serum samples as a herd-level surveillance tool for infectious production-limiting diseases: bovine viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR), enzootic bovine leukosis (EBL) and Neospora caninum (NC), by investigating the maximum number of samples one can pool to identify one positive animal, using commercial antibody-detection ELISAs. Four positive field standards (PFS), one for each disease, were prepared by pooling highly positive herd-level samples diagnosed using commercially available ELISA tests. These PFS were used to simulate 18 pooled samples ranging from undiluted PFS to a dilution representing 1 positive in 1,000 animals using phosphate-buffered saline as diluent. A 1:10 dilution of the PFS resulted in positive results for IBR, BVD and EBL. Moreover, for IBR and BVD, results were still positive at 1:100 and 1:30 dilutions, respectively. However, for NC, a lower dilution (8:10) was required for a seropositive result. This study indicates that, at herd-level, the use of pooled serum is a useful strategy for monitoring infectious diseases (BVD, IBR and EBL) but not NC, using readily available diagnostic assays.

Infectious bovine abortions: observations from an organized dairy herd.

Abortions in dairy animals can be caused by several infectious agents. Identification of the actual causal agent(s) is important for formulating suitable control strategies. A 3-year (2016-2018) longitudinal study was conducted in a dairy farm following an abortion storm in the mid- to late gestations. The investigation focused on the seven major infectious abortifacient in cattle, viz. bovine alphaherpesvirus-1 (BoHV-1), bovine viral diarrhoea virus (BVDV), Neospora caninum, Brucella abortus, Coxiella burnetii, Leptospira Hardjo, and Listeria monocytogenes. High seroprevalence was observed for BVDV (79.4%), Leptospira (70.5%), BoHV-1 (53.5%), and Brucella (45.0%) at the beginning of the investigation (August 2016). The incidence proportion increased for BVDV, Leptospira, and Brucella in the following years of the investigation. A strong association of Brucella seropositivity with history of abortion (OR = 3.27) was recorded. Incidence of BoHV-1 reduced during the period of study coincident with systematic IBR inactivated marker vaccination of the herd. Sixty-four abortion cases were investigated for the identification of causative agent(s) by microbial culture, serological (ELISA), and molecular detection (PCR/ real-time PCR). Antibodies to BVDV, Brucella, BoHV-1, Leptospira, Neospora, and Coxiella were detected in 63, 61, 56, 35, 5, and 6 aborting cattle, respectively. Real-time PCR/PCR of clinical specimens detected DNA of Brucella, BoHV-1, Coxiella, Leptospira, and Listeria in 34, 13, 12, 9, and 4 abortion cases, respectively. BVDV and Neospora were not detected in any specimen samples. Brucella abortus isolated from the farm was determined as ST1 by multi-locus sequence typing (MLST). DNA of multiple agents were detected in 21 of the 64 cases (43.75%). Overall, the data suggests, Brucella was the major causative agent, although multiple causative agents circulated in the farm.

Seroprevalence and intercurrence of reproductive pathogens in cattle from family farms in North of Minas Gerais, Brazil / Soroprevalência e intercorrência de patógenos reprodutivos em bovinos da agricultura familiar no Norte de Minas Gerais, Brasil

The aims of the present study were: to estimate the seroprevalence of Bluetongue vírus (BTV), bovine alphaherpesvirus 1 (BoHV-1), bovine viral diarrhea virus (BVDV), Brucella abortus and Leptospira spp. in cattle from family farms in North of Minas Gerais; to determine the intercurrence and association among these pathogens; and to assess the possible associated factors to seropositive herds and animals. For this, 476 cows from 46 farms were sampled and evaluated serologically. The seroprevalence in herds and cattle was, respectively, for BTV 100% and 52.0%, for BoHV-1 95.7% and 48.6%, for BVDV 78.3% and 46.1%, for Leptospira spp. 76.1% and 29.1%, and for B. abortus was 0% in herd and cattle. More than 65% of the herds was simultaneously seropositive for BTV, BoHV-1, BVDV and Leptospira spp. Seropositivity for BoHV-1, Leptospira spp. serovar Autumnalis and serovar Hardjoprajitno were associated with abortion, whereas seropositivity for BVDV was associated with BoHV-1. Moreover, association among seropositivity for BVDV, BoHV-1 and Leptospira spp. was also observed. In conclusion, BTV, BoHV-1, BVDV and Leptospira spp. are highly seroprevalent and occurred simultaneously in cattle from family farms in Minas Gerais, indicating the need for the implementation of control measures to avoid economic losses related to these diseases.(AU)

Os objetivos do presente estudo foram: i) estimar a soroprevalência de Bluetongue virus (BTV), bovine alphaherpesvirus 1 (BoHV-1), bovine viral diarrhea virus (BVDV), Brucella abortus e Leptospira spp. em bovinos da agricultura familiar no Norte de Minas Gerais, Brasil; ii) determinar a intercorrência e associação entre esses patógenos; iii) e avaliar os possíveis fatores associados aos rebanhos e animais soropositivos. Para isso, 476 vacas de 46 fazendas foram amostradas e avaliadas sorologicamente. A soroprevalência de rebanhos e animais foi, respectivamente, para BTV de 100% e 52.0%, para BoHV-1 de 95.7% e 48.6%, para BVDV de 78.3% e 46.1%, para Leptospira spp. de 76.1% e 29.1% e para B. abortus de 0% para ambos rebanhos e bovinos. Mais de 65% dos rebanhos foram simultaneamente soropositivos para BTV, BoHV-1, BVDV e Leptospira spp. A soropositividade para BoHV-1, Leptospira spp. sorovar Autumnalis e sorovar Hardjoprajitno foram fatores associados com aborto, enquanto soropositividade para BVDV foi fator associado com BoHV-1. Além disso, associação entre a soropositividade para BVDV, BoHV-1 e Leptospira spp. foi observada. Em conclusão, BTV, BVDV, BoHV-1 e Leptospira spp. são altamente soroprevalentes e ocorrem simultaneamente em bovinos da agricultura familiar de Minas Gerais, indicando a necessidade da implementação de medidas de controle para evitar perdas econômicas relacionadas a essas doenças.(AU)

Seroprevalence and intercurrence of reproductive pathogens in cattle from family farms in North of Minas Gerais, Brazil / Soroprevalência e intercorrência de patógenos reprodutivos em bovinos da agricultura familiar no Norte de Minas Gerais, Brasil

The aims of the present study were: to estimate the seroprevalence of Bluetongue vírus (BTV), bovine alphaherpesvirus 1 (BoHV-1), bovine viral diarrhea virus (BVDV), Brucella abortus and Leptospira spp. in cattle from family farms in North of Minas Gerais; to determine the intercurrence and association among these pathogens; and to assess the possible associated factors to seropositive herds and animals. For this, 476 cows from 46 farms were sampled and evaluated serologically. The seroprevalence in herds and cattle was, respectively, for BTV 100% and 52.0%, for BoHV-1 95.7% and 48.6%, for BVDV 78.3% and 46.1%, for Leptospira spp. 76.1% and 29.1%, and for B. abortus was 0% in herd and cattle. More than 65% of the herds was simultaneously seropositive for BTV, BoHV-1, BVDV and Leptospira spp. Seropositivity for BoHV-1, Leptospira spp. serovar Autumnalis and serovar Hardjoprajitno were associated with abortion, whereas seropositivity for BVDV was associated with BoHV-1. Moreover, association among seropositivity for BVDV, BoHV-1 and Leptospira spp. was also observed. In conclusion, BTV, BoHV-1, BVDV and Leptospira spp. are highly seroprevalent and occurred simultaneously in cattle from family farms in Minas Gerais, indicating the need for the implementation of control measures to avoid economic losses related to these diseases.

Os objetivos do presente estudo foram: i) estimar a soroprevalência de Bluetongue virus (BTV), bovine alphaherpesvirus 1 (BoHV-1), bovine viral diarrhea virus (BVDV), Brucella abortus e Leptospira spp. em bovinos da agricultura familiar no Norte de Minas Gerais, Brasil; ii) determinar a intercorrência e associação entre esses patógenos; iii) e avaliar os possíveis fatores associados aos rebanhos e animais soropositivos. Para isso, 476 vacas de 46 fazendas foram amostradas e avaliadas sorologicamente. A soroprevalência de rebanhos e animais foi, respectivamente, para BTV de 100% e 52.0%, para BoHV-1 de 95.7% e 48.6%, para BVDV de 78.3% e 46.1%, para Leptospira spp. de 76.1% e 29.1% e para B. abortus de 0% para ambos rebanhos e bovinos. Mais de 65% dos rebanhos foram simultaneamente soropositivos para BTV, BoHV-1, BVDV e Leptospira spp. A soropositividade para BoHV-1, Leptospira spp. sorovar Autumnalis e sorovar Hardjoprajitno foram fatores associados com aborto, enquanto soropositividade para BVDV foi fator associado com BoHV-1. Além disso, associação entre a soropositividade para BVDV, BoHV-1 e Leptospira spp. foi observada. Em conclusão, BTV, BVDV, BoHV-1 e Leptospira spp. são altamente soroprevalentes e ocorrem simultaneamente em bovinos da agricultura familiar de Minas Gerais, indicando a necessidade da implementação de medidas de controle para evitar perdas econômicas relacionadas a essas doenças.

Serosurvey for Infectious Agents Associated with Subfertility and Abortion in Dairy Cattle in Trinidad and Tobago, West Indies.

Despite frequent reports of subfertility and abortion in dairy cattle in Trinidad and Tobago (T&T), little is known about the potential infectious and non-infectious causes. This study set out to investigate possible infectious causes of reproductive problems by measuring the seroprevalence of four of the most significant reproductive pathogens in dairy cattle worldwide: Brucella abortus (B. abortus); Neospora caninum (N. caninum), Bovine Viral Diarrhoea virus (BVDV), and Infectious Bovine Rhinotracheitis virus (IBRV). These four reproductive pathogens have been suspected to be present in dairy cattle in T&T for some time but, previously, studies have not been carried out to confirm their presence. Bulk milk samples were collected from 92 dairy farms across Trinidad, representing a total of 1177 dairy cattle. Four dairy farms were selected for individual milk sampling to assess in-farm seroprevalence levels. Milk samples were tested for antibodies to the four pathogens by commercial ELISA kits. The overall farm seroprevalence was 62% for N. caninium and 23% for IBRV, and no antibodies were detected in any of the bulk milk samples for B. abortus or BVDV. Mixed infections for IBRV and N. caninum were common. Seroprevalence levels were between 8% and 65% for N. caninum and between 3% and 53% IBRV on the four individual farms. These results reveal the presence of IBRV and N. caninum for the first time on the island of Trinidad and importantly reveal no evidence for the circulation of BVDV or B. abortus in dairy cattle in Trinidad.

Presence of IgG antibodies against reproductive infections in breeding bulls of Magdalena Medio, Colombia / Presencia de anticuerpos tipo IgG contra infecciones reproductivas en toros reproductores de la región del Magdalena Medio, Colombia / Presença de anticorpos IgG contra infecções reprodutivas de touros reprodutores do Magdalena Médio, Colômbia

Background: cattle farming is an important economic activity in several regions of Colombia. However, farmers are unaware of their cattle health status, and particularly of bacterial, parasitic, and viral diseases, which affect reproduction and profitability. Objective: to assess the presence of IgG antibodies against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), bovine leukosis, leptospirosis, brucellosis, and Neospora caninum in breeding bulls in the Magdalena Medio of Colombia, according to age, breed, and origin. Methods: a descriptive, cross-sectional study was conducted with 174 male breeding cattle from several subspecies. Animals were above 18 months of age and belonged to dual-purpose farms in the Magdalena Medio region. Presence of IgG anti-IBR, BVD, brucellosis, neosporosis, and leukosis antibodies were determined with an enzyme-linked immunosorbent assay (ELISA). A sample of 156 males was assessed for leptospirosis using a microscopic agglutination test (MAT) in a dark field. Results: IgG anti-IBR antibodies were found in 92.5% of the animals, anti-BVD in 62.6%, anti-Neospora caninum in 79.3%, anti-Brucella abortus in 4.02%, anti-Leptospira pomona in 8.33%, and anti-L. hardjo in 15.38%, with >1:100 titres. Besides, 64.94% prevalence was observed for bovine leukosis. Conclusions: a high prevalence of IgG anti-IBR, IgG anti-BVD, IgG anti- Neospora caninum, IgG anti-leukosis, and IgG anti-lepstospirosis antibodies were observed in Magdalena Medio bulls. With respect to B. abortus, confirmatory and competitive ELISA test should be performed and sanitary standards need to be established. Detection of IgG antibodies among bulls reveals poor sanitary conditions, absent of protective-vaccination antibodies and an urgent need for health control measurements.

Antecedentes: la ganadería bovina es una importante actividad económica desarrollada en varias regiones del país, sin embargo, los ganaderos desconocen el estado sanitario de los bovinos con respecto a enfermedades bacterianas, parasitarias y virales, lo que afecta la reproducción y la rentabilidad. Objetivo: evidenciar la presencia de anticuerpos tipo IgG anti-rinotraqueitis infecciosa bovina (IBR), diarrea viral bovina (BVD), leucosis bovina, leptospirosis, brucelosis y Neospora caninum en los toros reproductores del Magdalena Medio colombiano, en asociación con variables de edad, raza y procedencia. Métodos: se realizó un estudio descriptivo de corte transversal en un grupo poblacional de 174 machos reproductores bovinos de diferentes subespecies. Los animales eran mayores de 18 meses en fincas destinadas a ganadería doble propósito ubicadas en la región del Magdalena Medio. Mediante un ensayo de inmunoabsorción enzimática (ELISA) se determinó la presencia de anticuerpos tipo IgG anti-IBR, BVD, brucelosis, neosporosis y leucosis. Para el caso de la leptospirosis, a 156 de los machos se les realizó la prueba de microaglutinación en campo oscuro (MAT). Resultados: se hallaron anticuerpos tipo IgG anti-IBR en un 92,5%, anti-BVD en el 62,6%, anti-Neospora caninum 79,3%, anti-Brucella abortus 4,02%, anti-Leptospira pomona 8,33% y anti-L. hardjo 15,38%, con títulos >1:100. Además, para leucosis bovina se obtuvo una prevalencia del 64,94%. Conclusión: se observaron altos porcentajes de casos con presencia de anticuerpos IgG anti-IBR, BVD, N. caninum, leucosis y lepstospirosis en el ganado bovino del Magdalena Medio colombiano. Para B. abortus debe realizarse la prueba confirmativa ELISA competitiva y aplicar la norma sanitaria. La determinación de anticuerpos tipo IgG permitió conocer el delicado estado sanitario de los reproductores bovinos, teniendo en cuenta que no han recibido ningún esquema de vacunación y se hace necesario un adecuado control sanitario.

Antecedentes: a pecuária é uma atividade econômica importante em várias regiões do país, no entanto, os agricultores não têm conhecimento do estado de saúde do gado em relação adoenças bacterianas, parasitárias e virais. É por esta razão que as perdas econômicas aumentam e diminuem a qualidade de reprodução. Objetivo: demonstrar a presença de anticorpos IgG para rinotraqueíte-viral bovina (IBR), diarréia viral bovina (BVD), leucose bovina, leptospirose, brucelose e Neospora caninum. Nos machos reprodutores do Magdalena Medio tendo em conta as variáveis idade, raça e origens. Métodos: i foi realizada estudo descritivo transversal em duas populações de 174 machos reprodutores de diferentes subespécies de gado com mais de 18 meses de edad procedentes de fazendas utilizadas para a pecuária de duplo propósito, localizadas na região do Madalena Médio. Para detectar a presença de anticorpos IgG anti-IBR, BVD, brucelose, e enzoótica, neosporose foi determinada pela técnica de ensaio imunoenzimático (ELISA). Para o caso de leptospirose foi realizado teste de microaglutinação em campo escuro (MAT). Resultados: anticorpos IgG anti-IBR foram encontrados em 92,5%, anti-BVD num 62,6%, anti-Neospora caninum num 79,3%, anti-Brucella abortus 4,02%, anti-Leptospira pomona num 8,33% e anti-L. hardjo 15,38% com títulos > 1:100. Para leucose bovina, uma percentagem de 64,94%, foi obtido. Conclusão: foram observados altos percentagens de casos na presença de anticorpos IgG anti-IBR, BVD, N. caninum, lepstospirosis e leucose nos bovinos do Madalena Médio colombiano, o teste confirmatorio ELISA competitivo. Para a determinação de B. abortus deve ser realizado e dar cumplimento a normatividade sanitaria. A determinação de anticorpos IgG tem permitido conhecer o delicado estado sanitario dos reprodutores bovinos, considerando que eles não receberam qualquer vacinação é necessário um adequado controle de saúde.

Natural infection in ovarian structures by bovine herpesvirus 1: molecular and serological detection / Infecção natural em estruturas ovarianas pelo Herpesvírus bovino 1: detecção molecular e sorológica

In this study, the polymerase chain reaction (PCR) was used to evaluate the presence of viral DNA in ovarian tissue, in the cumulus-oocyte complex (COC), follicular liquid, and blood of animals naturally infected with bovine herpesvirus-1 (BoHV-1). The serum profile of the sampled animals was also evaluated. Samples of serum, blood, ovarian tissue, follicular liquid, and COC were collected from 147 slaughterhouse animals that were not vaccinated against BoHV-1. Contaminated or insufficient samples were disregarded. Serological tests allowed the identification of serum-positive animals with neutralizing antibodies against BoHV-1. Analysis of samples by PCR revealed the presence of viral DNA in 0.9% (1/115) of the COC samples, in 4.3% (5/117) of the ovarian tissue samples, and in 2.8% (3/108) of the blood samples. Viral DNA was not detected in any of the follicular liquid samples. In serological samples, a positivity of 83.6% (117/140) was observed for BoHV-1. All PCR-positive animals, regardless of the samples analyzed, showed positivity in the serum neutralization test for the detection of BoHV-1-specific antibodies. According to these results, a high prevalence of antibodies against BoHV-1 was detected in naturally infected animals from different herds, and the molecular tests revealed the presence of viral DNA in bovine ovarian tissue, providing evidence that this might be...(AU)

Neste trabalho foi avaliada a presença do DNA viral, por meio da Reação em Cadeia da Polimerase (PCR), no tecido ovariano, nos oócitos, líquido folicular e sangue de vacas naturalmente infectadas. Também foi avaliado o perfil sorológico dos animais amostrados. Foram coletadas amostras de soro, sangue, tecido ovariano, líquido folicular e complexo cumulus-oócitos de 147 animais abatidos em frigorífico não vacinados contra o herpesvirus bovino 1 (BoHV-1). Amostras tóxicas ou insuficientes foram descartadas. Os testes sorológicos foram realizados permitindo a identificação dos animais soropositivos para anticorpos neutralizantes contra o BoHV-1. Foram realizadas as PCRs onde foi observada a presença do DNA viral em 0,9% (1/115) dos oócitos, em 4,3% (5/117) do tecido ovariano e em 2,8% (3/108) do sangue. Em nenhuma das amostras de líquido folicular foi detectado o DNA viral. Nas amostras sorológicas observou-se 83,6% (117/140) de positividade para o BoHV-1. Dentre os animais positivos na PCR, independente das amostras, todos apresentavam positividade no teste de soroneutralização para detecção de anticorpos para BoHV-1. Conclui-se que em animais de diferentes rebanhos analisados foi detectada alta prevalência de anticorpos contra o BoHV-1 e que nos testes moleculares houve a presença do DNA viral em amostras de tecidos ovarianos de bovinos, evidenciando que estas estruturas poderia...(AU)

Análise soroepidemiológica da infecção pelo herpesvírus bovino tipo 1 (BoHV-1) em bovinos no Estado de Pernambuco / Seroepidemiological survey of infection bovine herpesvirus type 1 (BoHV-1) in cattle in the state of Pernambuco

Background: The infection of vírus the Infectious Bovine Rhinotracheitis (IBR) is responsible for variety of clinical signs in cattle, highlighting problems in the reproductive tract which causes damage to the cattle. The objective of this work was to determine the prevalence and risk factors associated with infection by bovine herpesvirus type 1 (BoHV-1) in cattle herds in the micro Garanhuns, State of Pernambuco, Brazil.Materials, Methods & Results: Samples of 373 cows of reproductive age were collected (over 24 months), with milk aptitude and seven bulls, totaling 380 samples from herds without history of BoHV-1 vaccination, from 20 properties distributed in the municipalities that make up the study area during the months of April and May 2013. For serological diagnosis of infection with BoHV-1, we used the virus neutralization test (VN). In each farm, an epidemiological questionnaire to analyze risk factors with objective questions about the characteristics of production and aspects of hygiene and sanitary and reproductive management was applied. The analyze the risk factors associated with BoHV-1, it was performed a univariate analysis of the variables of interest using the chi-square test of Pearson or Fisher exact test, when necessary. Then, a logistic regression analysis dependent variable considering how to BoHV-1 virus neutralization test result (no reagent or reagent) was performed. The independent or explanatory variables considered in the model were those that showed statistical significance < 0.20. The prevalence was 79.5% (302/380; CI: 75.1% - 83.4%) of the 20 sampled properties, all had at least one positive animal, with prevalence in herds ranging from 46.2% to 100.0%.[...](AU)

Natural infection in ovarian structures by bovine herpesvirus 1: molecular and serological detection / Infecção natural em estruturas ovarianas pelo Herpesvírus bovino 1: detecção molecular e sorológica

In this study, the polymerase chain reaction (PCR) was used to evaluate the presence of viral DNA in ovarian tissue, in the cumulus-oocyte complex (COC), follicular liquid, and blood of animals naturally infected with bovine herpesvirus-1 (BoHV-1). The serum profile of the sampled animals was also evaluated. Samples of serum, blood, ovarian tissue, follicular liquid, and COC were collected from 147 slaughterhouse animals that were not vaccinated against BoHV-1. Contaminated or insufficient samples were disregarded. Serological tests allowed the identification of serum-positive animals with neutralizing antibodies against BoHV-1. Analysis of samples by PCR revealed the presence of viral DNA in 0.9% (1/115) of the COC samples, in 4.3% (5/117) of the ovarian tissue samples, and in 2.8% (3/108) of the blood samples. Viral DNA was not detected in any of the follicular liquid samples. In serological samples, a positivity of 83.6% (117/140) was observed for BoHV-1. All PCR-positive animals, regardless of the samples analyzed, showed positivity in the serum neutralization test for the detection of BoHV-1-specific antibodies. According to these results, a high prevalence of antibodies against BoHV-1 was detected in naturally infected animals from different herds, and the molecular tests revealed the presence of viral DNA in bovine ovarian tissue, providing evidence that this might be...

Neste trabalho foi avaliada a presença do DNA viral, por meio da Reação em Cadeia da Polimerase (PCR), no tecido ovariano, nos oócitos, líquido folicular e sangue de vacas naturalmente infectadas. Também foi avaliado o perfil sorológico dos animais amostrados. Foram coletadas amostras de soro, sangue, tecido ovariano, líquido folicular e complexo cumulus-oócitos de 147 animais abatidos em frigorífico não vacinados contra o herpesvirus bovino 1 (BoHV-1). Amostras tóxicas ou insuficientes foram descartadas. Os testes sorológicos foram realizados permitindo a identificação dos animais soropositivos para anticorpos neutralizantes contra o BoHV-1. Foram realizadas as PCRs onde foi observada a presença do DNA viral em 0,9% (1/115) dos oócitos, em 4,3% (5/117) do tecido ovariano e em 2,8% (3/108) do sangue. Em nenhuma das amostras de líquido folicular foi detectado o DNA viral. Nas amostras sorológicas observou-se 83,6% (117/140) de positividade para o BoHV-1. Dentre os animais positivos na PCR, independente das amostras, todos apresentavam positividade no teste de soroneutralização para detecção de anticorpos para BoHV-1. Conclui-se que em animais de diferentes rebanhos analisados foi detectada alta prevalência de anticorpos contra o BoHV-1 e que nos testes moleculares houve a presença do DNA viral em amostras de tecidos ovarianos de bovinos, evidenciando que estas estruturas poderia...

Análise soroepidemiológica da infecção pelo herpesvírus bovino tipo 1 (BoHV-1) em bovinos no Estado de Pernambuco / Seroepidemiological survey of infection bovine herpesvirus type 1 (BoHV-1) in cattle in the state of Pernambuco

Background: The infection of vírus the Infectious Bovine Rhinotracheitis (IBR) is responsible for variety of clinical signs in cattle, highlighting problems in the reproductive tract which causes damage to the cattle. The objective of this work was to determine the prevalence and risk factors associated with infection by bovine herpesvirus type 1 (BoHV-1) in cattle herds in the micro Garanhuns, State of Pernambuco, Brazil.Materials, Methods & Results: Samples of 373 cows of reproductive age were collected (over 24 months), with milk aptitude and seven bulls, totaling 380 samples from herds without history of BoHV-1 vaccination, from 20 properties distributed in the municipalities that make up the study area during the months of April and May 2013. For serological diagnosis of infection with BoHV-1, we used the virus neutralization test (VN). In each farm, an epidemiological questionnaire to analyze risk factors with objective questions about the characteristics of production and aspects of hygiene and sanitary and reproductive management was applied. The analyze the risk factors associated with BoHV-1, it was performed a univariate analysis of the variables of interest using the chi-square test of Pearson or Fisher exact test, when necessary. Then, a logistic regression analysis dependent variable considering how to BoHV-1 virus neutralization test result (no reagent or reagent) was performed. The independent or explanatory variables considered in the model were those that showed statistical significance < 0.20. The prevalence was 79.5% (302/380; CI: 75.1% - 83.4%) of the 20 sampled properties, all had at least one positive animal, with prevalence in herds ranging from 46.2% to 100.0%.[...]

Surveillance of neutralizing antibodies against Bovine Herpesvirus 1 in cattle herds from different farming property systems / Distribuição de anticorpos neutralizantes contra o Herpesvirus bovino 1 em propriedades bovinas de diferentes sistemas de criação

The aim of this study was to investigate the presence of neutralizing antibodies against bovine herpesvirus 1 (BoHV-1) in 722 non-vaccinated animals from eight properties that use different farming systems (extensive, semi-confinement and confinement). Serum samples were subjected to neutralization tests in order to search for anti-BoHV-1 antibodies. Serological results were categorized as negative, low titer, intermediate titer or high titer. One property showed no positive samples; while other properties presented frequency of positive samples ranging from 17.95% to 86.96%. For animals raised under confinement, the number of positive samples and neutralizing antibody titers were lower compared to others, possibly due to good sanitary practices adopted by this type of system. Altogether, our results can contribute towards the understanding of the endemic infection in Brazil.

Este trabalho teve por objetivo avaliar a distribuição de anticorpos neutralizantes contra o herpesvirus bovino 1 (BoHV-1) em 722 animais não vacinados pertencentes a oito propriedades que utilizam diferentes sistemas de criação (extensivo, semi-confinamento e confinamento). As amostras sorológicas foram submetidas ao teste de soroneutralização para pesquisa de anticorpos anti-BoHV-1. Os resultados foram classificados em títulos negativo, baixo, médio e alto. Uma propriedade não apresentou amostras positivas, enquanto que nas demais propriedades a frequência de amostras positivas variou de 17,95% a 86,96%. Os animais do sistema de criação por confinamento apresentaram menor número de amostras positivas quando comparado aos animais do outros sistemas de criação, possivelmente devido às boas práticas sanitárias adotadas por esse sistema. Dessa forma, nossos resultados podem contribuir para o entendimento dessa infecção endêmica no Brasil.

Analysis of isotype-specific antibody responses to bovine herpesviruses 1.1 and 1.2a allows to estimate the stage of infection

Specific IgM, IgA, IgG1, IgG2, as well as neutralizing antibody responses were evaluated in sera of calves experimentally infected with two isolates of bovine herpesvirus type 1 (BoHV1) of distinct subtypes (subtype 1, BoHV1.1; subtype 2a, BoHV-1.2a). No significant differences were observed in the antibody responses induced by each BoHV-1 subtype. The antibody responses following primary acute infection were characterized by an increase in specific IgM and IgA levels between days 2 and 14 post inoculation (pi). IgG1 was detected from days 11 to 30 pi. IgG2 was detected on the sample taken on day 30 pi. Reactivation of infection following dexamethasone administration induced a significant rise in IgA levels, whereas IgG1 and IgG2 levels, which were at high levels from the beginning of the reactivation process, showed a slight alteration after corticosteroid treatment. These results suggest that it is possible to estimate the dynamics of BoHV-1 infections with basis on the analysis of class- and subclass-specific antibody responses. Such information may be particularly useful for the study of the kinetics of the infection in a herd and to aid in the adoption of appropriate control measures..

Analysis of isotype-specific antibody responses to bovine herpesviruses 1.1 and 1.2a allows to estimate the stage of infection.

Specific IgM, IgA, IgG1, IgG2, as well as neutralizing antibody responses were evaluated in sera of calves experimentally infected with two isolates of bovine herpesvirus type 1 (BoHV1) of distinct subtypes (subtype 1, BoHV1.1; subtype 2a, BoHV-1.2a). No significant differences were observed in the antibody responses induced by each BoHV-1 subtype. The antibody responses following primary acute infection were characterized by an increase in specific IgM and IgA levels between days 2 and 14 post inoculation (pi). IgG1 was detected from days 11 to 30 pi. IgG2 was detected on the sample taken on day 30 pi. Reactivation of infection following dexamethasone administration induced a significant rise in IgA levels, whereas IgG1 and IgG2 levels, which were at high levels from the beginning of the reactivation process, showed a slight alteration after corticosteroid treatment. These results suggest that it is possible to estimate the dynamics of BoHV-1 infections with basis on the analysis of class- and subclass-specific antibody responses. Such information may be particularly useful for the study of the kinetics of the infection in a herd and to aid in the adoption of appropriate control measures..

Infecções por herpesvírus bovino tipo 1 (BoHV-1) e suas implicações na reprodução bovina / Infections caused by bovine herpesvirus 1 (BoHV-1) and its implications in bovine reproduction

Esta revisão enfoca o estudo das infecções causadas por herpesvírus bovino 1 (BoHV-1) e suas implicações na reprodução de bovinos, visto que as perdas mais expressivas na produtividade estão relacionadas a repetições de estro, abortamentos e nascimento de bezerros fracos ou natimortos decorrentes da infecção.(AU)

This work revises the infections caused by bovine herpesvirus 1 (BoHV-1) and its implications on the reproduction of cattle, as its most expressive productive losses are related to the repeating breeding, abortions, and the birth of weak or stillbirth calves due to the infection.(AU)

Infecções por herpesvírus bovino tipo 1 (BoHV-1) e suas implicações na reprodução bovina / Infections caused by bovine herpesvirus 1 (BoHV-1) and its implications in bovine reproduction

Esta revisão enfoca o estudo das infecções causadas por herpesvírus bovino 1 (BoHV-1) e suas implicações na reprodução de bovinos, visto que as perdas mais expressivas na produtividade estão relacionadas a repetições de estro, abortamentos e nascimento de bezerros fracos ou natimortos decorrentes da infecção.

This work revises the infections caused by bovine herpesvirus 1 (BoHV-1) and its implications on the reproduction of cattle, as its most expressive productive losses are related to the repeating breeding, abortions, and the birth of weak or stillbirth calves due to the infection.

Aislamiento delvvirus herpes bovino tipo 1 en bovinos del departamento de córdoba - Colombia / Isoation of boviine herpes virus type 1 from cattle in cordoba - Colombia

Objetivo. Realizar el aislamiento del virus herpes bovino tipo 1 (BHV-1) en ganado bovino con antecedentes de infertilidad. Materiales y métodos. A partir de 85 animales, provenientes de diferentes áreas rurales del departamento de Córdoba, Colombia, sin antecedentes de vacunación y con titulos neutralizantes contra la enfermedad de la rinotraqueitis bovina infecciosa (IBR) por seroneutralización, se escogieron dos toros y una vaca para hacer aislamiento de HVB-1. Los animales fueron inmunosuprimidos con Dexametasona, y se obtuvieron muestras con hisopos nasales, oculares y de lavado prepucial en los toros y vaginales en la vaca respectivamente. Resultados. Se observó un efecto citopático a las 3 horas después de la inoculación de las células MDBK con el lavado genital de la vaca y a las 24 horas en los toros, con exposición del efecto en "racimo" a las 48 horas. El aislamiento en ambos tipos de muestras, sugiere que la reactivación viral fue seguida por una fase de viremia y excreción del virus en las secreciones naturales. Conclusiones. El aislamiento del virus HVB-1 en los reproductores aparentemente sanos pero con títulos a la prueba de seroneutralización, establece la presencia de latencia viral en éstos animales, importante factor epidemiológico en la difusión de la enfermedad a nivel de campo. Se deben iniciar los estudios necesarios para establecer el subtipo de virus actuante en el campo, para conocer sus características antigénicas y su correspondencia con las cepas vacunales.

Objective. Bovine herpes virus type 1 (BHV-1) was isolated from beef cattle with history of infertility. Materials and methods. We chose 85 unvaccinated animals, from different rural areas of Cordoba Department that had evidence of infectious bovine rhinotracheitis (IBR) by serum neutralization. Two bulls and one cow were chosen to attempt isolation of HVB-1. The three bovines were immunosupressed with glucocorticoids (dexamethasone) and samples of prepucial washing (males) vaginal washing (female), and nasal and ocular swaps were obtained. Results. Cytopathic effect was detected 3 hours post-inoculation in the MDBK cells inoculated with vaginal washing of the cow and 24 hours post-inoculation in the cells inoculated with washings from the bulls. A "racime effect" appeared after 48 hours. Successful isolation from both types of samples, suggests that viral reactivation was followed by viremia and shedding of virus in natural secretions and excretions. Conclusions. The isolation of BHV-1 from apparently normal reproductive animals confirms the presence of viral latency in these animals. Latency is an important epidemiological factor in the spread of the disease among farm animals. Studies should be initiated to identify the viral subtype circulating understand its antigenic characteristics and match the virus to a vaccine strain.

In vitro characterization of gE negative bovine herpesvirus types 1.1 (BHV-1.1) and 1.2a (BHV-1.2a)

This study aimed the in vitro growth characterization of a previously constructed Brazilian bovine herpesvirus 1.2a with a deletion in the glycoprotein E gene (BHV-1.2a gE-). The plaque sizes, penetration and growth kinetics of the Brazilian BHV-1.2a gE- were studied and compared with the parental virus, as well as with a BHV-1.1 gE- recombinant derived from an European BHV-1.1 strain. No statistical differences were observed between the gE- recombinants and the respective parental viruses penetration assays were performed. When single step growth curves were studied, no statistical differences were observed between gE- and parental viruses. However, it was observed that both gE- viruses were excreted from cells in significantly higher titres at 11 hours post infection in comparison with parental viruses. No statistical differences were observed when plaque sizes of parental viruses or gE- viruses we analyzed separately in each cell type. However, both gE- recombinants displayed a significantly reduced plaque areas on three different cell cultures, in comparison with parental viruses, indicating that the lack of gE had the same effect on both BHV-1 subtypes, manifested by a restricted cell-to-cell spread in infected cells.

O presente estudo teve como objetivo a caracterização das propriedades de crescimento in vitro de uma amostra brasileira de herpesvírus bovino tipo 1.2a que apresenta uma deleção no gene que codifica a glicoproteína E (BHV-1.2a gE-). Os tamanhos de placa, cinética de penetração e cinética de multiplicação do vírus BHV-1.2a gE- foram estudados e comparados com o vírus parental, bem como com um vírus BHV-1.1 gE- recombinante, o qual é derivado de uma amostra européia de BHV-1.1. Em termos de cinética de penetração, não foram observadas diferenças significativas quando comparados os vírus gE- com os parentais. A determinação da cinética de multiplicação não demonstrou diferenças significativas entre os quatro vírus estudados. Foi entretanto observado que 11 horas pós infecção os dois vírus gE- foram excretados das células em títulos significativamente maiores do que os vírus parentais. Não foram observadas diferenças significativas quando comparados os diâmetros de placas formadas pelos dois vírus parentais. Da mesma forma, os diâmetros de placas dos vírus gE- foram semelhantes nos três tipos celulares estudados. Entretanto, a comparação dos diâmetros de placas entre os vírus gE- e os parentais mostrou uma redução significativa das placas dos vírus gE- em todos os tipos celulares. Esta característica indica que a falta da gE teve o mesmo efeito em ambos os subtipos de BHV-1, representado por uma disseminação viral célula-célula reduzida.

Construction and characterization of a glycoprotein E deletion mutant of bovine herpesvirus type 1.2 strain isolated in Brazil

This paper describes the construction and characterization of a Brazilian strain of bovine herpesvirus type 1.2a (BoHV-1.2a) with a deletion of the glycoprotein E (gE) gene. The deletion was introduced by co-transfection of a deletion fragment containing the 5´and 3´gE flanking regions and genomic DNA of wild type BoHV-1 into bovine cells. Isolation of gE deletion mutant was performed by immunoperoxidase staining with an anti-gE monoclonal antibody. Viral clones were plaque purified and further examined by restriction endonuclesase digestion and Southern blot hybridization. This gE deletion mutant will be evaluated as a vaccinal virus, in order to determine its potential use for a differential vaccine.

Este artigo descreve a construção e caracterização de uma amostra de um herpesvírus bovino tipo 1.2a (BoHV-1.2a) que apresenta uma deleção na região genômica que codifica a glicoproteína E (gE). A deleção gênica foi induzida através da co-transfecção de um fragmento de deleção, contendo as regiões 5´e 3´flanqueadoras da gE, com o DNA viral intacto de uma amostra viral isolada de um animal que apresentava doença respiratória. O isolamento do vírus gE negativo (gE-) foi realizado com auxílio da técnica de imunoperoxidase em que foi utilizado como anticorpo primário um anticorpo monoclonal anti-gE. O vírus gE- foi purificado e o DNA isolado desta amostra foi examinado através das técnicas de análise por enzimas de restrição e "Southern blot". Esta amostra gE- será avaliada como candidata para compor uma vacina diferencial contra a rinotraqueíte infecciosa dos bovinos.