Herd-level prevalence and risk factors for bovine viral diarrhea virus infection in cattle in the State of Paraíba, Northeastern Brazil.

Serological surveys based on a planned sampling on bovine viral diarrhea virus (BVDV) infection in Brazilian cattle herds are scarce. A cross-sectional study was carried out to determine herd- and animal-level seroprevalences and to identify risk factors associated with herd-level seroprevalence for BVDV infection in the State of Paraíba, Northeastern Brazil, from September 2012 to January 2013. The state was divided into three sampling strata, and for each stratum, the prevalence of herds infected with BVDV and the prevalence of seropositive animals was estimated by a two-stage sampling survey. In total, 2443 animals were sampled from 478 herds. A virus-neutralization test was used for BVDV antibody detection. A herd was considered positive when at least one seropositive animal was detected. The herd- and animal-level prevalences in the State of Paraíba were 65.5% (95% confidence interval (CI) = 61.1-69.7%) and 39.1% (95% CI = 33.1-45.6%), respectively. The frequency of seropositive animals per herd ranged from 10 to 100% (median of 50%). The risk factors identified were as follows: more than six calves aged ≤12 months (odds ratio (OR) = 3.72; 95% CI = 2.08-6.66), animal purchasing (OR = 1.66; 95% CI = 1.08-2.55), pasture rental (OR = 2.15; 95% CI = 1.35-3.55), and presence of veterinary assistance (OR = 2.04; 95% CI = 1.10-3.79). Our findings suggest that the implementation of control and prevention measures among farmers, with the aim of preventing dissemination of the agent in the herds, is necessary. Special attention should be given to addressing the identified risk factors, such as sanitary control prior to animal purchasing and to discourage the pasture rental, as well as to encourage the vaccination in the herds.

Serological response of guinea pigs to oily and aqueous inactivated vaccines containing a Brazilian isolate of the Bovine Viral Diarrhea Virus (BVDV).

Bovine Viral Diarrhea Virus (BVDV) is widespread in cattle in Brazil and research shows its large antigenic variability. Available vaccines are produced with virus strains isolated in other countries and may not be effective. In this study, inactivated vaccines containing the Brazilian BVDV-Ib IBSP11 isolate were developed and tested on 6 groups of 10 guinea pigs (Cavia porcellus). Animals in groups A and C received an aqueous vaccine (aluminum hydroxide); B and D groups received an oily vaccine (Montanide ISA50); Group E positive-control animals were given an imported commercial vaccine with BVDV-Ia Singer; Group F animals were sham vaccinated (negative control). Groups A, B and E received two doses, and Groups C and D, three, every 21 days. Twelve blood samples were taken, at 21-day intervals over 231 days, and evaluated for antibody titer through virus-neutralization (VN), using a homologous strain (IBSP11), and a heterologous strain (BVDV-Ia NADL). Most animals, 42 days following the first dose, seroconverted to both strains and, after the second dose, there was a significant increase of titers in all groups. The oily formulation induced greater response after the third administration. This increase was not observed with the aqueous vaccines, regardless of the virus used in the VN. Antibody decline was more rapid in animals that received aqueous vaccines. The results showed the importance of studying the influence of endemic strains of commercial vaccines, to improve the efficacy of BVD vaccination. Use of the endemic strain in vaccine formulation presented promising results, as well as the use of guinea pigs as a laboratory model.

Epidemiological analysis of infection by the bovine viral diarrhea virus on family farms in Brazil / Análise epidemiológica da infecção pelo vírus da diarreia viral bovina em rebanhos da agricultura familiar, Brasil

The aim of the present study was to determine the seroprevalence of infection by the bovine viral diarrhea virus (BVDV) on family farms, as well as to study the risk factors associated with the infection. In total, 319 blood serum samples were collected from cattle, of reproductive age (>24 months) in 24 herds from 11 cities of the brejo microregion in Pernambuco. The samples were subjected to the seroneutralization test to detect anti-BVDV antibodies. In order to identify the risk factors associated with the BVDV, a questionnaire epidemiologic was applied and followed by statistical analysis of logistic regression, with the serological test considered as the dependent variable (reagent or non-reagent). A prevalence of 51.1% (163/319; C.I. 45.5% - 56.7%) was found in the present study. Of the 24 herds sampled, 100.0% contained at least one reagent animal. The prevalence in the counties ranged from 23.1% to 70.0%. The following risk factors were identified in the present study: not providing colostrum (OR 3.85; p=0.018); disease unknown (OR 2.54; p=0.001) and consortium breeding (OR 1.76; p=0.013). Based on these results, it was clear that BVDV infection is widespread in herds on family farms in the microregion studied herein. Health education policies must be implemented for producers and professionals who provide technical assistance. In addition, based on the risk factors identified in the present study, hygiene-sanitary measures should be implemented in order to reduce the prevalence of the BVDV.(AU)

Objetivou-se com este estudo determinar a soroprevalência e estudar os fatores de risco associados à infecção pelo vírus da diarreia viral bovina (BVDV) nas unidades produtivas de agricultura familiar. Foram coletadas 319 amostras de soro sanguíneo, de bovinos em idade reprodutiva (>24 meses), procedentes de 24 rebanhos bovinos em 11 municípios da microrregião brejo pernambucano. As amostras foram submetidas ao teste de soroneutralização para detecção de anticorpos anti-BVDV. Para a identificação dos fatores de risco associados ao BVDV, foi aplicado um questionário epidemiológico e foi realizada uma análise estatística de regressão logística, considerando como variável dependente o exame sorológico (reagente ou não reagente). Observou-se com este estudo uma prevalência de 51,1% (163/319; I.C. 45,5% - 56,7%). Dos 24 rebanhos amostrados, 100% apresentaram pelo menos um animal reagente. A prevalência nos municípios variou de 23,1% a 70,0%. Os fatores de risco identificados neste estudo foram: não fornecer colostro (OR 3,85; p=0,018); não conhecer a enfermidade (OR 2,54; p=0,001) e criação consorciada (OR 1,76; p=0,013). Diante dos resultados obtidos, constatou-se que a infecção pelo BVDV está disseminada nos rebanhos de agricultura familiar na microrregião estudada e que políticas de educação em saúde devem ser implementadas tanto para os produtores como para os profissionais que prestam assistência técnica. Além disso, medidas higiênico-sanitárias com base nos fatores de risco identificados neste estudo devem ser implementadas como forma de reduzir a prevalência do BVDV.(AU)

Epidemiological analysis of infection by the bovine viral diarrhea virus on family farms in Brazil / Análise epidemiológica da infecção pelo vírus da diarreia viral bovina em rebanhos da agricultura familiar, Brasil

The aim of the present study was to determine the seroprevalence of infection by the bovine viral diarrhea virus (BVDV) on family farms, as well as to study the risk factors associated with the infection. In total, 319 blood serum samples were collected from cattle, of reproductive age (>24 months) in 24 herds from 11 cities of the brejo microregion in Pernambuco. The samples were subjected to the seroneutralization test to detect anti-BVDV antibodies. In order to identify the risk factors associated with the BVDV, a questionnaire epidemiologic was applied and followed by statistical analysis of logistic regression, with the serological test considered as the dependent variable (reagent or non-reagent). A prevalence of 51.1% (163/319; C.I. 45.5% - 56.7%) was found in the present study. Of the 24 herds sampled, 100.0% contained at least one reagent animal. The prevalence in the counties ranged from 23.1% to 70.0%. The following risk factors were identified in the present study: not providing colostrum (OR 3.85; p=0.018); disease unknown (OR 2.54; p=0.001) and consortium breeding (OR 1.76; p=0.013). Based on these results, it was clear that BVDV infection is widespread in herds on family farms in the microregion studied herein. Health education policies must be implemented for producers and professionals who provide technical assistance. In addition, based on the risk factors identified in the present study, hygiene-sanitary measures should be implemented in order to reduce the prevalence of the BVDV.

Objetivou-se com este estudo determinar a soroprevalência e estudar os fatores de risco associados à infecção pelo vírus da diarreia viral bovina (BVDV) nas unidades produtivas de agricultura familiar. Foram coletadas 319 amostras de soro sanguíneo, de bovinos em idade reprodutiva (>24 meses), procedentes de 24 rebanhos bovinos em 11 municípios da microrregião brejo pernambucano. As amostras foram submetidas ao teste de soroneutralização para detecção de anticorpos anti-BVDV. Para a identificação dos fatores de risco associados ao BVDV, foi aplicado um questionário epidemiológico e foi realizada uma análise estatística de regressão logística, considerando como variável dependente o exame sorológico (reagente ou não reagente). Observou-se com este estudo uma prevalência de 51,1% (163/319; I.C. 45,5% - 56,7%). Dos 24 rebanhos amostrados, 100% apresentaram pelo menos um animal reagente. A prevalência nos municípios variou de 23,1% a 70,0%. Os fatores de risco identificados neste estudo foram: não fornecer colostro (OR 3,85; p=0,018); não conhecer a enfermidade (OR 2,54; p=0,001) e criação consorciada (OR 1,76; p=0,013). Diante dos resultados obtidos, constatou-se que a infecção pelo BVDV está disseminada nos rebanhos de agricultura familiar na microrregião estudada e que políticas de educação em saúde devem ser implementadas tanto para os produtores como para os profissionais que prestam assistência técnica. Além disso, medidas higiênico-sanitárias com base nos fatores de risco identificados neste estudo devem ser implementadas como forma de reduzir a prevalência do BVDV.

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)

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%.[...]

A experiência brasileira na erradicação da febre aftosa e o emprego do sistema I-ELISA 3ABC/EITB para certificação sanitária de bovinos e bubalinos

ABSTRACT: Vaccination against foot-and-mouth disease is an effective tool for eradication and prevention of this disease. However, the presence of non-capsidal proteins (NCP) in the vaccine, produced during viral replication, has been the main problem, since their presence hamper the vigilance as its relies on the detection of antibodies against NCP to differentiate vaccinated from infected animals. Therefore, the Brazilian Ministry of Agriculture, Livestock and Supply published the Normative Instruction 50 (IN 50) that included the detection of antibodies against the NCP to evaluate the removal of these proteins. Considering the vaccine interference, this paper aimed to evaluate the frequency of reagents to NCP, analyzed by I-ELISA 3ABC/EITB system in the Laboratory of Bovine Viruses (LVB), Biological Institute (IB), São Paulo, SP, Brazil, from 2002 to 2012. Of the 34,705 cattle examined, it was observed that the proportion of reagents to NCP increased with age, indicating increased frequency of reagents in animals that received more vaccines, showing interference of proteins in response to vaccination. When compared before and after the publication of IN 50, there was decreased reactivity, with reduction in 2010, of nearly half compared to 2007, and even higher when compared with 2002 to 2006. This shows the effectiveness of the purification of the vaccine in response to the implementation of IN 50, although it remains some seroreactivity in cattle with multiple vaccinations. The I-ELISA 3ABC/EITB system proved to be a great tool to prevent the movement of possible carriers of the virus derived from vaccinated herds, provided that all sanitary and epidemiological context are taken in consideration.

RESUMO: A vacinação contra febre aftosa é ferramenta eficaz para erradicação e prevenção da doença, contudo, a presença de proteínas não capsidais (PNC) na vacina, produzidas durante a multiplicação viral, tem sido o principal problema, visto que sua presença dificulta as ações de vigilância, cuja busca se baseia na detecção de anticorpos contra essas proteínas para diferenciar animal vacinado de infectado. Por esse motivo, o Ministério da Agricultura, Pecuária e Abastecimento publicou em 2008 a Instrução Normativa nº 50 (IN 50), que incluiu no controle da qualidade da vacina a pesquisa de anticorpos contra as PNC, para avaliar a retirada dessas proteínas. Considerando a interferência vacinal, objetivou-se avaliar a frequência de bovinos reagentes às PNC, analisada pelo sistema I-ELISA 3ABC/EITB, no Laboratório de Viroses de Bovídeos do Instituto Biológico de São Paulo, no período de 2002 a 2012. Dos 34.705 bovinos examinados, observou-se que a proporção de reagentes às PNC aumentou com a idade, evidenciando aumento da frequência de reagentes em animais que receberam maior número de vacinações, indicando interferência da vacinação na resposta às proteínas. Quando comparados antes e após a publicação da IN 50, observa-se diminuição da reatividade, com redução, em 2010, de quase a metade em relação a 2007, e ainda maior quando comparado com o período 2002 a 2006. Isso demonstra a efetividade da purificação da vacina em resposta ao cumprimento da IN 50, embora permaneça alguma sororreatividade em bovinos com múltiplas vacinações. O sistema I-ELISA 3ABC/EITB demonstrou ser uma ótima ferramenta para impedir a movimentação de possíveis portadores do vírus oriundos de rebanhos vacinados, desde que seja considerado todo o contexto sanitário e epidemiológico.

The Brazilian experience in the eradication of foot-and-mouth disease and the use of I-ELISA 3ABC/EITB system for sanitary certification of bovine and buffaloes / A experiência brasileira na erradicação da febre aftosa e o emprego do sistema I-ELISA 3ABC/EITB para certificação sanitária de bovinos e bubalinos

Vaccination against foot-and-mouth disease is an effective tool for eradication and prevention of this disease. However, the presence of non-capsidal proteins (NCP) in the vaccine, produced during viral replication, has been the main problem, since their presence hamper the vigilance as its relies on the detection of antibodies against NCP to differentiate vaccinated from infected animals. Therefore, the Brazilian Ministry of Agriculture, Livestock and Supply published the Normative Instruction 50 (IN 50) that included the detection of antibodies against the NCP to evaluate the removal of these proteins. Considering the vaccine interference, this paper aimed to evaluate the frequency of reagents to NCP, analyzed by I-ELISA 3ABC/EITB system in the Laboratory of Bovine Viruses (LVB), Biological Institute (IB), São Paulo, SP, Brazil, from 2002 to 2012. Of the 34,705 cattle examined, it was observed that the proportion of reagents to NCP increased with age, indicating increased frequency of reagents in animals that received more vaccines, showing interference of proteins in response to vaccination. When compared before and after the publication of IN 50, there was decreased reactivity, with reduction in 2010, of nearly half compared to 2007, and even higher when compared with 2002 to 2006. This shows the effectiveness of the purification of the vaccine in response to the implementation of IN 50, although it remains some seroreactivity in cattle with multiple vaccinations. The I-ELISA 3ABC/EITB system proved to be a great tool to prevent the movement of possible carriers of the virus derived from vaccinated herds, provided that all sanitary and epidemiological context are taken in consideration.(AU)

A vacinação contra febre aftosa é ferramenta eficaz para erradicação e prevenção da doença, contudo, a presença de proteínas não capsidais (PNC) na vacina, produzidas durante a multiplicação viral, tem sido o principal problema, visto que sua presença dificulta as ações de vigilância, cuja busca se baseia na detecção de anticorpos contra essas proteínas para diferenciar animal vacinado de infectado. Por esse motivo, o Ministério da Agricultura, Pecuária e Abastecimento publicou em 2008 a Instrução Normativa nº 50 (IN 50), que incluiu no controle da qualidade da vacina a pesquisa de anticorpos contra as PNC, para avaliar a retirada dessas proteínas. Considerando a interferência vacinal, objetivou-se avaliar a frequência de bovinos reagentes às PNC, analisada pelo sistema I-ELISA 3ABC/EITB, no Laboratório de Viroses de Bovídeos do Instituto Biológico de São Paulo, no período de 2002 a 2012. Dos 34.705 bovinos examinados, observou-se que a proporção de reagentes às PNC aumentou com a idade, evidenciando aumento da frequência de reagentes em animais que receberam maior número de vacinações, indicando interferência da vacinação na resposta às proteínas. Quando comparados antes e após a publicação da IN 50, observa-se diminuição da reatividade, com redução, em 2010, de quase a metade em relação a 2007, e ainda maior quando comparado com o período 2002 a 2006. Isso demonstra a efetividade da purificação da vacina em resposta ao cumprimento da IN 50, embora permaneça alguma sororreatividade em bovinos com múltiplas vacinações. O sistema I-ELISA 3ABC/EITB demonstrou ser uma ótima ferramenta para impedir a movimentação de possíveis portadores do vírus oriundos de rebanhos vacinados, desde que seja considerado todo o contexto sanitário e epidemiológico.(AU)

A experiência brasileira na erradicação da febre aftosa e o emprego do sistema I-ELISA 3ABC/EITB para certificação sanitária de bovinos e bubalinos / The Brazilian experience in the eradication of foot-and-mouth disease and the use of I-ELISA 3ABC/EITB system for sanitary certification of bovine and buffaloes

A vacinação contra febre aftosa é ferramenta eficaz para erradicação e prevenção da doença, contudo, a presença de proteínas não capsidais (PNC) na vacina, produzidas durante a multiplicação viral, tem sido o principal problema, visto que sua presença dificulta as ações de vigilância, cuja busca se baseia na detecção de anticorpos contra essas proteínas para diferenciar animal vacinado de infectado. Por esse motivo, o Ministério da Agricultura, Pecuária e Abastecimento publicou em 2008 a Instrução Normativa nº 50 (IN 50), que incluiu no controle da qualidade da vacina a pesquisa de anticorpos contra as PNC, para avaliar a retirada dessas proteínas. Considerando a interferência vacinal, objetivou-se avaliar a frequência de bovinos reagentes às PNC, analisada pelo sistema I-ELISA 3ABC/EITB, no Laboratório de Viroses de Bovídeos do Instituto Biológico de São Paulo, no período de 2002 a 2012. Dos 34.705 bovinos examinados, observou-se que a proporção de reagentes às PNC aumentou com a idade, evidenciando aumento da frequência de reagentes em animais que receberam maior número de vacinações, indicando interferência da vacinação na resposta às proteínas. Quando comparados antes e após a publicação da IN 50, observa-se diminuição da reatividade, com redução, em 2010, de quase a metade em relação a 2007, e ainda maior quando comparado com o período 2002 a 2006. Isso demonstra a efetividade da purificação da vacina em resposta ao cumprimento da IN 50, embora permaneça alguma sororreatividade em bovinos com múltiplas vacinações. O sistema I-ELISA 3ABC/EITB demonstrou ser uma ótima ferramenta para impedir a movimentação de possíveis portadores do vírus oriundos de rebanhos vacinados, desde que seja considerado todo o contexto sanitário e epidemiológico.(AU)

Vaccination against foot-and-mouth disease is an effective tool for eradication and prevention of this disease. However, the presence of non-capsidal proteins (NCP) in the vaccine, produced during viral replication, has been the main problem, since their presence hamper the vigilance as its relies on the detection of antibodies against NCP to differentiate vaccinated from infected animals. Therefore, the Brazilian Ministry of Agriculture, Livestock and Supply published the Normative Instruction 50 (IN 50) that included the detection of antibodies against the NCP to evaluate the removal of these proteins. Considering the vaccine interference, this paper aimed to evaluate the frequency of reagents to NCP, analyzed by I-ELISA 3ABC/EITB system in the Laboratory of Bovine Viruses (LVB), Biological Institute (IB), São Paulo, SP, Brazil, from 2002 to 2012. Of the 34,705 cattle examined, it was observed that the proportion of reagents to NCP increased with age, indicating increased frequency of reagents in animals that received more vaccines, showing interference of proteins in response to vaccination. When compared before and after the publication of IN 50, there was decreased reactivity, with reduction in 2010, of nearly half compared to 2007, and even higher when compared with 2002 to 2006. This shows the effectiveness of the purification of the vaccine in response to the implementation of IN 50, although it remains some seroreactivity in cattle with multiple vaccinations. The I-ELISA 3ABC/EITB system proved to be a great tool to prevent the movement of possible carriers of the virus derived from vaccinated herds, provided that all sanitary and epidemiological context are taken in consideration.(AU)

The Brazilian experience in the eradication of foot-and-mouth disease and the use of I-ELISA 3ABC/EITB system for sanitary certification of bovine and buffaloes / A experiência brasileira na erradicação da febre aftosa e o emprego do sistema I-ELISA 3ABC/EITB para certificação sanitária de bovinos e bubalinos

Vaccination against foot-and-mouth disease is an effective tool for eradication and prevention of this disease. However, the presence of non-capsidal proteins (NCP) in the vaccine, produced during viral replication, has been the main problem, since their presence hamper the vigilance as its relies on the detection of antibodies against NCP to differentiate vaccinated from infected animals. Therefore, the Brazilian Ministry of Agriculture, Livestock and Supply published the Normative Instruction 50 (IN 50) that included the detection of antibodies against the NCP to evaluate the removal of these proteins. Considering the vaccine interference, this paper aimed to evaluate the frequency of reagents to NCP, analyzed by I-ELISA 3ABC/EITB system in the Laboratory of Bovine Viruses (LVB), Biological Institute (IB), São Paulo, SP, Brazil, from 2002 to 2012. Of the 34,705 cattle examined, it was observed that the proportion of reagents to NCP increased with age, indicating increased frequency of reagents in animals that received more vaccines, showing interference of proteins in response to vaccination. When compared before and after the publication of IN 50, there was decreased reactivity, with reduction in 2010, of nearly half compared to 2007, and even higher when compared with 2002 to 2006. This shows the effectiveness of the purification of the vaccine in response to the implementation of IN 50, although it remains some seroreactivity in cattle with multiple vaccinations. The I-ELISA 3ABC/EITB system proved to be a great tool to prevent the movement of possible carriers of the virus derived from vaccinated herds, provided that all sanitary and epidemiological context are taken in consideration.

A vacinação contra febre aftosa é ferramenta eficaz para erradicação e prevenção da doença, contudo, a presença de proteínas não capsidais (PNC) na vacina, produzidas durante a multiplicação viral, tem sido o principal problema, visto que sua presença dificulta as ações de vigilância, cuja busca se baseia na detecção de anticorpos contra essas proteínas para diferenciar animal vacinado de infectado. Por esse motivo, o Ministério da Agricultura, Pecuária e Abastecimento publicou em 2008 a Instrução Normativa nº 50 (IN 50), que incluiu no controle da qualidade da vacina a pesquisa de anticorpos contra as PNC, para avaliar a retirada dessas proteínas. Considerando a interferência vacinal, objetivou-se avaliar a frequência de bovinos reagentes às PNC, analisada pelo sistema I-ELISA 3ABC/EITB, no Laboratório de Viroses de Bovídeos do Instituto Biológico de São Paulo, no período de 2002 a 2012. Dos 34.705 bovinos examinados, observou-se que a proporção de reagentes às PNC aumentou com a idade, evidenciando aumento da frequência de reagentes em animais que receberam maior número de vacinações, indicando interferência da vacinação na resposta às proteínas. Quando comparados antes e após a publicação da IN 50, observa-se diminuição da reatividade, com redução, em 2010, de quase a metade em relação a 2007, e ainda maior quando comparado com o período 2002 a 2006. Isso demonstra a efetividade da purificação da vacina em resposta ao cumprimento da IN 50, embora permaneça alguma sororreatividade em bovinos com múltiplas vacinações. O sistema I-ELISA 3ABC/EITB demonstrou ser uma ótima ferramenta para impedir a movimentação de possíveis portadores do vírus oriundos de rebanhos vacinados, desde que seja considerado todo o contexto sanitário e epidemiológico.

A experiência brasileira na erradicação da febre aftosa e o emprego do sistema I-ELISA 3ABC/EITB para certificação sanitária de bovinos e bubalinos

ABSTRACT: Vaccination against foot-and-mouth disease is an effective tool for eradication and prevention of this disease. However, the presence of non-capsidal proteins (NCP) in the vaccine, produced during viral replication, has been the main problem, since their presence hamper the vigilance as its relies on the detection of antibodies against NCP to differentiate vaccinated from infected animals. Therefore, the Brazilian Ministry of Agriculture, Livestock and Supply published the Normative Instruction 50 (IN 50) that included the detection of antibodies against the NCP to evaluate the removal of these proteins. Considering the vaccine interference, this paper aimed to evaluate the frequency of reagents to NCP, analyzed by I-ELISA 3ABC/EITB system in the Laboratory of Bovine Viruses (LVB), Biological Institute (IB), São Paulo, SP, Brazil, from 2002 to 2012. Of the 34,705 cattle examined, it was observed that the proportion of reagents to NCP increased with age, indicating increased frequency of reagents in animals that received more vaccines, showing interference of proteins in response to vaccination. When compared before and after the publication of IN 50, there was decreased reactivity, with reduction in 2010, of nearly half compared to 2007, and even higher when compared with 2002 to 2006. This shows the effectiveness of the purification of the vaccine in response to the implementation of IN 50, although it remains some seroreactivity in cattle with multiple vaccinations. The I-ELISA 3ABC/EITB system proved to be a great tool to prevent the movement of possible carriers of the virus derived from vaccinated herds, provided that all sanitary and epidemiological context are taken in consideration.

RESUMO: A vacinação contra febre aftosa é ferramenta eficaz para erradicação e prevenção da doença, contudo, a presença de proteínas não capsidais (PNC) na vacina, produzidas durante a multiplicação viral, tem sido o principal problema, visto que sua presença dificulta as ações de vigilância, cuja busca se baseia na detecção de anticorpos contra essas proteínas para diferenciar animal vacinado de infectado. Por esse motivo, o Ministério da Agricultura, Pecuária e Abastecimento publicou em 2008 a Instrução Normativa nº 50 (IN 50), que incluiu no controle da qualidade da vacina a pesquisa de anticorpos contra as PNC, para avaliar a retirada dessas proteínas. Considerando a interferência vacinal, objetivou-se avaliar a frequência de bovinos reagentes às PNC, analisada pelo sistema I-ELISA 3ABC/EITB, no Laboratório de Viroses de Bovídeos do Instituto Biológico de São Paulo, no período de 2002 a 2012. Dos 34.705 bovinos examinados, observou-se que a proporção de reagentes às PNC aumentou com a idade, evidenciando aumento da frequência de reagentes em animais que receberam maior número de vacinações, indicando interferência da vacinação na resposta às proteínas. Quando comparados antes e após a publicação da IN 50, observa-se diminuição da reatividade, com redução, em 2010, de quase a metade em relação a 2007, e ainda maior quando comparado com o período 2002 a 2006. Isso demonstra a efetividade da purificação da vacina em resposta ao cumprimento da IN 50, embora permaneça alguma sororreatividade em bovinos com múltiplas vacinações. O sistema I-ELISA 3ABC/EITB demonstrou ser uma ótima ferramenta para impedir a movimentação de possíveis portadores do vírus oriundos de rebanhos vacinados, desde que seja considerado todo o contexto sanitário e epidemiológico.

Humoral immunity assessment in calves born to cows immunized with inactivated vaccine for Bovine Herpesvirus 1 and Bovine Viral Diarrhea Virus

Background: Considering that calves are immunologically immature at birth, maternal vaccination at the precalving period has been used as an alternative approach to increase the antibody titers in the colostrum, providing better immunological assistance to neonates. This study aimed to evaluate the influence of maternal immunization with inactivated vaccine for Bovine Herpesvirus type I (BoHV-1) and Bovine Viral Diarrhea virus (BVDV) at the precalving period on the transfer of passive immunity to calves.Material, Methods & Results: Eleven pregnant cows were divided into non-vaccinated (C, control; n = 4) and vaccinated (VAC; n = 7) groups. The vaccinated cows were seronegative for BVDV, but two animals of the control group presented titers for BoHV-1 due to natural exposure. The immunization was performed at 60 and 30 days precalving by using a commercially available vaccine from Argentine that consisted of inactivated strains of BVDV-1, BVDV-2, and BoHV-1. Calves were fed 4 L of colostrum in the first 12 h after birth. Colostrum and blood samples were collected from calves before (T0) and after colostrum feeding up to 15th day (T1-T6). Specific antibodies (ABs) in the colostrum and serum were detected using serum neutralization (SN) test. At T0, AB titers for BVDV and BoHV-1 were not detected in the blood serum of calves. Only one cow from the VAC group had ABs for BVDV...

Humoral immunity assessment in calves born to cows immunized with inactivated vaccine for Bovine Herpesvirus 1 and Bovine Viral Diarrhea Virus

Background: Considering that calves are immunologically immature at birth, maternal vaccination at the precalving period has been used as an alternative approach to increase the antibody titers in the colostrum, providing better immunological assistance to neonates. This study aimed to evaluate the influence of maternal immunization with inactivated vaccine for Bovine Herpesvirus type I (BoHV-1) and Bovine Viral Diarrhea virus (BVDV) at the precalving period on the transfer of passive immunity to calves.Material, Methods & Results: Eleven pregnant cows were divided into non-vaccinated (C, control; n = 4) and vaccinated (VAC; n = 7) groups. The vaccinated cows were seronegative for BVDV, but two animals of the control group presented titers for BoHV-1 due to natural exposure. The immunization was performed at 60 and 30 days precalving by using a commercially available vaccine from Argentine that consisted of inactivated strains of BVDV-1, BVDV-2, and BoHV-1. Calves were fed 4 L of colostrum in the first 12 h after birth. Colostrum and blood samples were collected from calves before (T0) and after colostrum feeding up to 15th day (T1-T6). Specific antibodies (ABs) in the colostrum and serum were detected using serum neutralization (SN) test. At T0, AB titers for BVDV and BoHV-1 were not detected in the blood serum of calves. Only one cow from the VAC group had ABs for BVDV...(AU)

Systemic and local antibodies induced by an experimental inactivated vaccine against bovine herpesvirus type 1 / Anticorpos locais e sistêmicos induzidos por uma vacina experimental inativada contra o herpesvírus bovino tipo 1

An experimental inactivated vaccine against bovine herpesvirus-1 (BoHV-1) was produced aiming to evaluate the systemic and local antibody responses in 12 seronegative heifers, after vaccination and revaccination. Serum samples were submitted to virus neutralization assay and to ELISA test for detection of IgG1 and IgG2 isotypes. Nasal secretion samples were submitted to the same ELISA test for detection of IgG1 and IgG2 isotypes. The results showed that moderate to high neutralizing titres and IgG1 and IgG2 antibody responses were induced after the second vaccination in the serum and in nasal secretions up to 114 days post vaccination. IgG2 antibodies were the prevalent isotype for most of the post-vaccination period. The results indicate that BoHV-1 experimental inactivated vaccine elicited potentially protective IgG1 and IgG2 antibody levels, both in the systemic and mucosal compartments.

Uma vacina experimental inativada contra o herpesvírus bovino tipo 1 (BoHV-1) foi produzida com o objetivo de se avaliar a resposta imune humoral local e sistêmica contra o BoHV-1, em 12 novilhas soronegativas, após a vacinação e a revacinação. Os soros foram submetidos à prova de vírus-neutralização para quantificação do título de anticorpos neutralizantes e a um ELISA para detecção de IgG1 e IgG2. Os swabs nasais também foram submetidos ao ELISA para detecção de IgG1 e IgG2 na secreção nasal. Os resultados demonstraram que títulos de anticorpos neutralizantes foram induzidos após a revacinação, em níveis moderados a altos, permanecendo em níveis significativos no soro sanguíneo e na secreção nasal até o dia 114 pós-vacinação. O IgG2 foi o isótipo predominante na maior parte do período pós-vacinação, tanto na secreção nasal, como no compartimento sistêmico. A vacina experimental inativada contra o BoHV-1 estimulou níveis de anticorpos potencialmente protetores dos isótipos IgG1 e IgG2, tanto no compartimento sistêmico, como nas mucosas.

Occurrence of seropositive sheep (Ovis aries) to bovine leukemia virus in Brazil / Ocorrência de ovinos (Ovis aries) soropositivos ao vírus da leucemia bovina no Brasil

Occurrence of seropositive sheep (Ovis aries) to Bovine Leukemia Virus (BLV) by agar-gel immunodiffusion test (AGID) using the antigen gp51 was surveyed for the period 2005-2007. Samples were collected from sheep in the Brazilian states of Rio Grande do Sul, Paraná, São Paulo, Pernambuco, Maranhão, Pará, Bahia, Mato Grosso, Rondônia, and Acre. Two of 35 (5.7%) flocks were seropositive to BLV, and the rate of seropositive animals was 0.077% (two of 2,592). The two seropositive sheep were female, one 13-month old Santa Inês breed and other of unknown age and breed, both from the state of São Paulo. Distribution of BLV in the ovine population studied proved to be a rare event in Brazil.

A ocorrência de ovinos sororreagentes ao vírus da Leucemia Bovina (VLB) pelo teste de imunodifusão em gel de ágar (IDGA) utilizando o antígeno gp51 foi avaliada no período de 2005-2007, em diferentes regiões do Brasil. Amostras foram colhidas de ovinos dos Estados do Rio Grande do Sul, Paraná, São Paulo, Pernambuco, Maranhão, Pará, Bahia, Mato Grosso, Rondônia e Acre. Duas em 35 cabanhas (5,7%) e dois em 2592 ovinos (0,077%) foram soropositivos. Os únicos animais com anticorpos contra o VLB eram fêmeas, uma com 13 meses de idade e da raça Santa Inês e a outra não se conhecia a idade e raça, ambas provenientes do Estado de São Paulo. A distribuição da soropositividade na população estudada demonstrou ser rara a infecção pelo VLB em ovinos no Brasil.

Occurrence of seropositive sheep (Ovis aries) to Bovine Leukemia Virus in Brazil / Ocorrência de ovinos (Ovis aries) soropositivos ao vírus da Leucemia Bovina no Brasil

Occurrence of seropositive sheep (Ovis aries) to Bovine Leukemia Virus (BLV) by agar-gel immunodiffusion test (AGID) using the antigen gp51 was surveyed for the period 2005-2007. Samples were collected from sheep in the Brazilian states of Rio Grande do Sul, Paraná, São Paulo, Pernambuco, Maranhão, Pará, Bahia, Mato Grosso, Rondônia, and Acre. Two of 35 (5.7%) flocks were seropositive to BLV, and the rate of seropositive animals was 0.077% (two of 2,592). The two seropositive sheep were female, one 13-month old Santa Inês breed and other of unknown age and breed, both from the state of São Paulo. Distribution of BLV in the ovine population studied proved to be a rare event in Brazil. (AU)

A ocorrência de ovinos sororreagentes ao vírus da Leucemia Bovina (VLB) pelo teste de imunodifusão em gel de ágar (IDGA) utilizando o antígeno gp51 foi avaliada no período de 2005-2007, em diferentes regiões do Brasil. Amostras foram colhidas de ovinos dos Estados do Rio Grande do Sul, Paraná, São Paulo, Pernambuco, Maranhão, Pará, Bahia, Mato Grosso, Rondônia e Acre. Duas em 35 cabanhas (5,7%) e dois em 2592 ovinos (0,077%) foram soropositivos. Os únicos animais com anticorpos contra o VLB eram fêmeas, uma com 13 meses de idade e da raça Santa Inês e a outra não se conhecia a idade e raça, ambas provenientes do Estado de São Paulo. A distribuição da soropositividade na população estudada demonstrou ser rara a infecção pelo VLB em ovinos no Brasil. (AU)

Avaliação da virusneutralização cruzada frente BVDV - 1 e BVDV - 2 no diagnóstico da diarréia viral bovina em animais naturalmente infectados / Evaluation of the cross virus neutralization against BVDV-1 and BVDV-2 in the diagnosis of bovine viral diarrhea in naturally infected animals

A Diarréia Viral Bovina (BVD) provoca grandes perdas econômicas na pecuária mundial, é causada pelo vírus da diarréia viral bovina (BVDV), vírus que apresenta diversidade genética e antigênica entre as estirpes o que provavelmente influencia no diagnóstico. Com a proposta de verificar a presença de anticorpos, sua mensuração e neutralização cruzada frente quatro estirpes do vírus, amostras de 1500 bovinos não vacinados contra BVDV, sendo 519 de 15 rebanhos do Estado de Minas Gerais (MG), 499 de cinco rebanhos do Mato Grosso do Sul (MS) e 482 de cinco rebanhos de São Paulo (SP), foram testadas pela técnica de virusneutralização (VN) com as seguintes estirpes citopatogênicas: BVDV-1 (NADL estirpe americana e IBSP-11 isolado nacional) e BVDV-2 (VS-253 estirpe americana e IBSP-1020 isolado nacional). Dos 1500 animais, a variação da frequência de sororreagentes ao BVDV foi de 66,07% a 68,67%, ao analisar os diferentes grupos de animais, de acordo com o estado, a maior frequência de anticorpos foi obtida no MS, seguida por MG e SP, independente da estirpe utilizada na VN. O isolado nacional do genótipo 2, IBSP-1020 foi a estirpe que resultou em maior detecção de reagentes em MG e MS, enquanto que em SP foram as estirpes do genótipo 1. A avaliação dos resultados com as quatro estirpes revelou 73,27% (1099/1500) de animais reagentes a pelo menos um dos vírus, enquanto que, 57,60% (864/1500) foram reagentes aos quatro vírus, simultaneamente, ou seja, estes animais produziram anticorpos que reagiram com todas as estirpes em questão. Os títulos de anticorpos variaram de 10, valor mínimo de detecção da prova, a 5120, sendo que a maior parte dos animais apresentou títulos entre 40 e 160, os títulos observados nos animais de SP foram mais baixos com relação aos animais dos outros estados. A avaliação dos títulos de anticorpos de cada animal, comparando o resultado das estirpes duas a duas, revelou diferença na maioria das situações. Conclui-se que, houve alta frequência de ocorrência de bovinos reagentes ao BVDV, que variou de acordo com o sistema de criação e manejo dos rebanhos. Além disso, a utilização de mais de uma estirpe viral, independente do genótipo ou do local de origem do isolado, aumentou a sensibilidade de detecção de animais sororreagentes na VN. Foi evidenciada neutralização cruzada entre todas as estirpes estudadas. Os resultados reforçam a importância de selecionar estirpes representativas das regiões a serem estudadas para inclusão na VN, visando aumentar a sensibilidade do diagnóstico

The bovine viral diarrhea (BVD) causes great economic losses in livestock worldwide, is caused by bovine viral diarrhea virus (BVDV), which presents genetic and antigenic diversity among strains which probably influences the serological diagnosis. For the proposal to verify the presence and titers of antibodies and cross-neutralization against four strains of virus, samples from 1,500 bovines naturally infected with BVDV, from the States of Minas Gerais (MG), Mato Grosso do Sul (MS) and São Paulo (SP) were tested by the virus-neutralization test (VN), against four cytopathic strains: BVDV-1 (NADL - American strain and IBSP-11 Brazilian isolate) and BVDV-2 (VS-253 - American strain and IBSP-1020 - Brazilian isolate). Of the 1,500 animals, the range from 66.07% to 68.67%, were reactive to BVDV, and the increased frequency of antibodies was obtained in the state of MS, followed by MG and SP, independent of the BVDV strain used in the VN. The national isolate of the genotype 2, IBSP-1020 strain showed highest detection of reagents in MG and MS states, while in SP were the strains of genotype 1. The results with the four strains showed that 73.27% (1,099/1,500) of animals positive to at least one virus, whereas 57.60% (864/1,500) were simultaneously reactive to the four viruses, in other words that is, these animals produced antibodies that cross reacted against all strains in question. The titers of antibodies ranged from 10, the minimum value of detection of VN, to 5120, and that most animals were between 40 and 160 titers. In comparison of antibodies titers among states was observed that animals in SP presented lowest antibody titer that other states. The evaluation of titers of antibodies in each animal, comparing the results of two by two strains showed statistical difference in most situations. It is concluded that there was a high frequency of occurrence of bovine reagents to BVDV, which varied according to the system of rasing and management of herds. Moreover, the use of different viral strains, independently of genotype or place of origin of isolate, increased the sensitivity of detection of seropositive animals in the VN. Cross-neutralization was observed among all strains studied. To increase the sensitivity of diagnosis it is important to select for VN the strains representative of the regions to be studied