Presence of co-infection between bovine leukemia virus and bovine herpesvirus 1 in herds vaccinated against bovine respiratory complex.

The aim of this study was molecular identification of bovine leukemia virus and possible co-infection with bovine respiratory disease complex (BRDC) viral agents in Mexican dairy herds. We collected 533 blood samples from cattle vaccinated against the BRDC virus in 9 states across Mexico. Peripheral blood leukocytes were removed and genetic material was extracted to detect bovine leukemia virus (BLV), bovine herpesvirus 1 (BoHV-1), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus 3 (BPIV-3), and bovine respiratory syncytial virus (BRSV) infection using polymerase chain reaction. We identified high BLV infection rates in 270 cattle (50.65%). One hundred and thirty-three cows (24.95%) tested positive for BoHV-1, of which 65 samples were positive for both viruses (BoHV-1 and BLV) and 68 were only positive for BoHV-1. Only 4 samples tested positive for BPIV-3 and no sample was positive for BVDV or BRSV. Relative risk and odds ratio analyses did not identify that the presence of BLV infection favors BoHV-1 co-infection in vaccinated herds.

Le but de cette étude était l'identification moléculaire du virus de la leucémie bovine et une éventuelle co-infection par des agents viraux du complexe des maladies respiratoires bovines (BRDC) dans des troupeaux laitiers mexicains. Nous avons recueilli 533 échantillons de sang de bovins vaccinés contre le virus BRDC dans neuf états du Mexique. Les leucocytes du sang périphérique ont été prélevés et le matériel génétique a été extrait pour détecter le virus de la leucémie bovine (BLV), le virus de l'herpès bovin 1 (BoHV-1), le virus de la diarrhée virale bovine (BVDV), le virus parainfluenza bovin 3 (BPIV-3), et le virus respiratoire syncytial bovin (BRSV) par réaction d'amplification en chaîne par la polymérase. Nous avons identifié des taux élevés d'infection par le BLV chez 270 bovins (50,65 %). Cent trente-trois bovins (24,95 %) ont été testés positifs pour le BoHV-1, desquels 65 échantillons étaient positifs pour les deux virus (BoHV-1 et BLV) et 68 étaient uniquement positifs pour le BoHV-1. Seuls quatre échantillons ont été testés positifs pour le BPIV-3 et aucun échantillon n'a été positif pour le BVDV ou le BRSV. Les analyses du risque relatif et des rapports de cotes n'ont pas identifié que la présence d'une infection par le BLV favorise la co-infection par le BoHV-1 dans les troupeaux vaccinés.(Traduit par les auteurs).

Descriptive cross-sectional study on major bovine diseases and associated risk factors in north-eastern Ecuadorian Amazon / Estudo transversal descritivo sobre as principais doenças bovinas e fatores de risco associados no nordeste da Amazônia equatoriana

Cattle raising is a crucial element of production systems in the tropics and subtropics. However, in recent years, global public health security has been threatened by disease emergence. In Orellana Province, livestock is the most important activity to generate economic income. Nevertheless, there is no available data about Animal Health status. With this objective, a study was performed to describe the major Bovine diseases recorded between 2011 to 2019, and the main Risk factors associated. Data on main Bovine diseases were retrieved from the World Animal Health Information System database. Whereas Bovine population data used to calculate the prevalence rates and confidence intervals were obtained from Ecuador's Ministry of Agriculture. By contrast, the Risk factors identified with an epidemiological questionnaire were applied to 300 livestock farmers. As a result, from 2011 to 2019 in Orellana has been confirmed: 90 cases of Infectious Bovine Rhinotracheitis (31.58%), Bovine Rabies by hematophagous bats (Desmodus rotundus), 83 cases (29.12%), Bovine viral diarrhea with 43 cases (15.10%), Brucellosis by Brucella abortus 35 cases, which was (12.28%), and 34 cases related to Enzootic bovine leukosis (11.92%). Overall, the prevalence rates ranged from (0.24 to 15.37%). In addition, farm size, presence of forest, herd, and paddock sizes, cutting frequency of forages, and other animal species were involved as Risk factors (OR = 3.15 to 11.75; 95% CI, 0.01 to 0.69). In conclusion, there are animal diseases with reproductive and neurologic symptomology and high-Risk factors implicated in the transmission. Consequently, space-temporal and seroprevalence epidemiological studies should be performed in Orellana.

A criação de gado é um elemento crucial dos sistemas de produção nos trópicos e subtrópicos. No entanto, nos últimos anos, a segurança da saúde pública global tem sido ameaçada pelo surgimento de doenças. Na província de Orellana, a pecuária é a atividade mais importante para gerar renda econômica. Contudo, não há dados disponíveis sobre o estado de saúde animal. Com este objetivo, foi realizado um estudo para descrever as principais doenças dos bovinos registradas entre 2011 e 2019, além dos principais fatores de risco associados. Os dados sobre as principais doenças bovinas foram recuperados do banco de dados do World Animal Health Information System. Os dados da população bovina usados para calcular as taxas de prevalência e os intervalos de confiança foram obtidos do Ministério da Agricultura do Equador. Por outro lado, os fatores de risco identificados com um questionário epidemiológico foram aplicados a 300 criadores de gado. Como resultado, de 2011 a 2019 em Orellana foram confirmados: 90 casos (31,58%) de rinotraqueíte infecciosa bovina, 83 casos (29,12%) de raiva bovina por morcegos hematófagos (Desmodus rotundus), 43 casos (15,10%) de diarreia viral bovina, 35 casos (12,28%) de brucelose por Brucella abortus e 34 casos relacionados à leucose enzoótica bovina (11,92%). No geral, as taxas de prevalência variaram de 0,24 a 15,37%. Além disso, tamanho da fazenda, presença de floresta, tamanho do rebanho e dos piquetes, frequência de corte de forragens e outras espécies animais estiveram envolvidos como fatores de risco (OR = 3,15-11,75; IC 95% 0,01-0,69). Em conclusão, existem doenças animais com sintomatologia reprodutiva e neurológica e fatores de alto risco implicados na transmissão. Portanto, estudos epidemiológicos espaço-temporais e de soroprevalência devem ser realizados em Orellana.

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.

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.

Bayesian estimation of herd-level prevalence and risk factors associated with BoHV-1 infection in cattle herds in the State of Paraíba, Brazil.

A cross-sectional study was carried out to estimate the animal- and herd-level prevalence of bovine herpesvirus 1 (BoHV-1) infection in cattle in the State of Paraíba, and to identify risk factors associated with herd-level infection. The state was divided into three sampling strata, and for each stratum, the prevalence of herds infected with BoHV-1 was estimated through a two-stage sampling survey carried out from September 2012 to January 2013. In total, 2443 animals were sampled from 478 herds. A virus-neutralization test was used for BoHV-1 antibody detection. A Bayesian latent-class model was used to describe the data, taking into account imperfect diagnostic test characteristics and the non-independence of test results from animals within the same herd, and using a dynamic within-model risk factor selection method based on indicator variable selection. The adjusted herd-level prevalence was estimated to be 84% (95% CI: 80-88%) for the State of Paraíba, and the animal-level prevalence was estimated to be 73% (95% CI: 66-84%). Only five of the available risk factors were used by the model, with the three most influential being disposal of aborted foetuses (3.78, 95% CI: 1.11-13.85), sharing resources with other farms (3.0, 95% CI: 1.1-8,6), and a herd size of > 23 animals (2.5, 95% CI: 1.1-6.0). Our findings suggest that the animal- and herd-level seroprevalence of BoHV-1 infection in the State of Paraíba is high. While some risk factors such as herd size and sharing resources were identified as risk factors for BoHV-1 infection, these risk factors are initially likely to be of only minor relevance in a control programme due to the extremely high prevalence of infected farms. However, the results are relevant to the risk of reintroduction of disease on farms that have previously eradicated the disease.

Soroprevalência de herpesvírus bovino tipo 1 em fêmeas bovinas na microrregião do Vale do Rio dos Bois, Goiás, Brasil / Seroprevalence of bovine herpesvirus type 1 in bovine females in the microregion of the Vale do Rio dos Bois, Goias, Brazil

Livestock is one of the main activities of the gross domestic Product (GDP), exercising a fundamental role in the land use and occupation process in Brazil. Infectious diseases, bacterial, viral or parasitic origin, may affect the reproductive system of both males and females, causing a series of problems of infertility with different levels of occurrence. One of the most important diseases that affect the reproductive sphere of viral origin and that have already been identified in cattle in Brazil the infectious bovine rhinotracheitis (IBR). The aim of this work was to carry out an epidemiological study in the State of Goiás, specifically in the Vale do Rio dos Bois microregion (municipalities of Cezarina, Mairipotaba and Pontalina), detecting the presence of antibodies to the IBR, by vírusneutralização (VN). The properties studied were found a seroprevalence of 96.4% for neutralizing antibodies against IBR in bovine females over 24 months. The results found in this study showed that there is a high prevalence of infection for BoHV-1 at Vale do Rio dos Bois microregion. The data for these studies can serve as a base to plot strategies for the control of the disease, with the guidance of producers.

A pecuária constitui uma das principais atividades econômicas contribuintes para o Produto Interno Bruto (PIB) brasileiro, exercendo papel fundamental no processo de uso e ocupação de terras no Brasil. Doenças infecciosas de origem bacteriana, viral ou parasitária podem afetar o sistema reprodutivo, tanto dos machos como das fêmeas, causando uma série de problemas de infertilidade nos rebanhos, com diferentes níveis de gravidade. Dentre as doenças mais importantes de origem viral que afetam a natureza reprodutiva e que já foram identificadas em bovinos no Brasil, destaca-se a Rinotraqueíte Infecciosa Bovina (IBR). O objetivo deste trabalho foi realizar um estudo epidemiológico no estado de Goiás, especificamente na Microrregião do Vale do Rio dos Bois (municípios de Cezarina, Mairipotaba e Pontalina), detectando a presença de anticorpos contra a IBR pelo teste de vírus-neutralização (VN). Das propriedades estudadas, foi encontrada uma soroprevalência de 96,4% para anticorpos neutralizantes contra a IBR em fêmeas bovinas acima de 24 meses. Os resultados encontrados no presente estudo demonstraram que há uma elevada taxa de prevalência da infecção por BoHV-1 na Microrregião do Vale do Rio dos Bois. Os dados deste estudo poderão servir de base para se traçarem estratégias para o controle da doença, com orientação aos produtores.

Soroprevalência de herpesvírus bovino tipo 1 em fêmeas bovinas na microrregião do Vale do Rio dos Bois, Goiás, Brasil / Seroprevalence of bovine herpesvirus type 1 in bovine females in the microregion of the Vale do Rio dos Bois, Goias, Brazil

Livestock is one of the main activities of the gross domestic Product (GDP), exercising a fundamental role in the land use and occupation process in Brazil. Infectious diseases, bacterial, viral or parasitic origin, may affect the reproductive system of both males and females, causing a series of problems of infertility with different levels of occurrence. One of the most important diseases that affect the reproductive sphere of viral origin and that have already been identified in cattle in Brazil the infectious bovine rhinotracheitis (IBR). The aim of this work was to carry out an epidemiological study in the State of Goiás, specifically in the Vale do Rio dos Bois microregion (municipalities of Cezarina, Mairipotaba and Pontalina), detecting the presence of antibodies to the IBR, by vírusneutralização (VN). The properties studied were found a seroprevalence of 96.4% for neutralizing antibodies against IBR in bovine females over 24 months. The results found in this study showed that there is a high prevalence of infection for BoHV-1 at Vale do Rio dos Bois microregion. The data for these studies can serve as a base to plot strategies for the control of the disease, with the guidance of producers.(AU)

A pecuária constitui uma das principais atividades econômicas contribuintes para o Produto Interno Bruto (PIB) brasileiro, exercendo papel fundamental no processo de uso e ocupação de terras no Brasil. Doenças infecciosas de origem bacteriana, viral ou parasitária podem afetar o sistema reprodutivo, tanto dos machos como das fêmeas, causando uma série de problemas de infertilidade nos rebanhos, com diferentes níveis de gravidade. Dentre as doenças mais importantes de origem viral que afetam a natureza reprodutiva e que já foram identificadas em bovinos no Brasil, destaca-se a Rinotraqueíte Infecciosa Bovina (IBR). O objetivo deste trabalho foi realizar um estudo epidemiológico no estado de Goiás, especificamente na Microrregião do Vale do Rio dos Bois (municípios de Cezarina, Mairipotaba e Pontalina), detectando a presença de anticorpos contra a IBR pelo teste de vírus-neutralização (VN). Das propriedades estudadas, foi encontrada uma soroprevalência de 96,4% para anticorpos neutralizantes contra a IBR em fêmeas bovinas acima de 24 meses. Os resultados encontrados no presente estudo demonstraram que há uma elevada taxa de prevalência da infecção por BoHV-1 na Microrregião do Vale do Rio dos Bois. Os dados deste estudo poderão servir de base para se traçarem estratégias para o controle da doença, com orientação aos produtores.(AU)

Evidence of bovine viral diarrhea, but absence of infectious bovine rhinotracheitis and bovine brucellosis in the endangered huemul deer (Hippocamelus bisulcus) in Chilean Patagonia.

We screened 18 endangered Chilean huemul (Hippocamelus bisulcus) for antibodies to infectious agents. We detected no antibody to bovine herpesvirus-1 (BHV-1) or Brucella abortus (BA); two huemul had antibody to bovine viral diarrhea virus (BVDV). Cattle (n=35) had antibody to BVDV and BHV-1 but not BA.

Seroprevalence of infectious bovine rhinotracheitis and bovine viral diarrhea virus type 1 and type 2 in non-vaccinated cattle herds in the Pacific Region of Central Costa Rica.

The objectives of this cross-sectional study were to estimate the seroprevalence of infectious bovine rhinotracheitis (IBR, BHV-1) and bovine viral diarrhea virus (BVDV) in a population of non-vaccinated, double purpose, dairy and beef herds in the Pacific Region of Central Costa Rica. Blood samples were collected from a total of 496 animals from 35 herds. Sera were tested for antibodies against BHV-1(IBR) and BVDV types 1 and 2 using serum neutralization test. The average number of animals tested in each herd for each of the viruses was 14. Overall individual seroprevalence was 48%, 27%, and 19% for IBR, BVDV type 1, and BVDV type 2, respectively. Median within-herd seroprevalence for IBR, BVDV type 1 and type 2 were 43%, 27%, and 24%, respectively.

Intraherd correlation coefficients and design effects for bovine viral diarrhoea, infectious bovine rhinotracheitis, leptospirosis and neosporosis in cow-calf system herds in North-eastern Mexico.

Knowledge of the intraherd correlation coefficient (ICC) and design (D) effect for infectious diseases could be of interest in sample size calculation and to provide the correct standard errors of prevalence estimates in cluster or two-stage samplings surveys. Information on 813 animals from 48 non-vaccinated cow-calf herds from North-eastern Mexico was used. The ICC for the bovine viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR), leptospirosis and neosporosis diseases were calculated using a Bayesian approach adjusting for the sensitivity and specificity of the diagnostic tests. The ICC and D values for BVD, IBR, leptospirosis and neosporosis were 0.31 and 5.91, 0.18 and 3.88, 0.22 and 4.53, and 0.11 and 2.68, respectively. The ICC and D values were different from 0 and D greater than 1, therefore large sample sizes are required to obtain the same precision in prevalence estimates than for a random simple sampling design. The report of ICC and D values is of great help in planning and designing two-stage sampling studies.

Seroconversion to bovine viral diarrhoea virus and infectious bovine rhinotracheitis virus in dairy herds of Michoacan, Mexico.

Bovine viral diarrhoea virus (BVDV) and infectious bovine rhinotracheitis virus (IBRV) are important viral diseases around the world. The objective of this study was to estimate the incidence of seroconversion to BVDV and IBRV and to identify associated risk factors in dairy herds of Michoacan, Mexico. The longitudinal study included 62 herds and ran from December 2001 to November 2002. The total number of animals enrolled and completing the study were 392 and 342 animals for BVDV and 925 and 899 animals for IBRV. Animals were tested monthly for 12 months, for the presence of antibodies. Risk factors were: herd size (2-9, 10-25 and 26-55 animals), herd serostatus (seropositive or seronegative, only for IBRV), age group of the animal (6 to 12, 13 to 24, 25 to 48 and > 48 months) and animal origin (born in farm, purchased). The cumulative incidences for BVDV and IBRV were 16.4% and 3.4%, respectively; whereas, the incidence density rates for BVDV and IBRV were 15.9 and 2.9 per 1000 animal-months at risk, respectively. Seroconversion curves were statistically different for age group for BVDV and IBRV and for herd status for IBR. The relatively high incidence of seroconversion for BVDV suggests that a successful control programme should be oriented towards the identification and elimination of the PI animals and towards avoiding the introduction of PI cattle to the farm. The scenario of IBRV is favourable to implement a programme directed to reduce the number of new seropositive herds.

High prevalence of co-infections with bovine herpesvirus 1 and 5 found in cattle in southern Brazil.

Based on small scale studies or on little sensitive serological tests, bovines in the south of the state of Rio Grande do Sul, Brazil, are known to be infected with either bovine herpesvirus 1 (BoHV-1) or 5 (BoHV-5). However, whether the prevalence of each of these viruses is high or low is currently still unknown. In order to determine the extent of BoHV (-1 and/or -5) infections in bovines in this region of Brazil, 200 bovines were studied for the presence of BoHV DNA. To this end, first a quantitative PCR was developed that amplified BoHV-1 DNA as well as BoHV-5 DNA. Using this PCR the number of BoHV genomes normally present in latently infected ganglia of naturally infected bovines was estimated. The new PCR was sensitive enough to detect most BoHV DNA in infected ganglia. The results of this first PCR showed that at least 87% of the bovines in the south of Rio Grande do Sul were (latently) infected with either BoHV-1 or BoHV-5. To determine the prevalence of BoHV-1 and BoHV-5 separately, two type-specific PCRs - one for each virus - were developed that used the products of the first PCR as a template. The results of these type-specific PCRs showed that 82.8% of the BoHV positive population was (latently) infected with BoHV-1, 93.1% with BoHV-5 and 75.9% with both BoHV-1 and BoHV-5. This is the first time that such a high frequency of co-infection of BoHV-1 and BoHV-5 in bovines has been demonstrated.

Seroepidemiología de la rinotraqueitis infecciosa bovina en el municipio de Montería, Colombia / Seroepidemiology of the infectious bovine rhinotracheitis in the municipality of Montería, Colombia

Objetivo. Estudiar la sero prevalencia de IBR en ganado bovino con antecedentes de infertilidad. Materiales y métodos. Se recolectaron 150 muestras de sangre de hembras con antecedentes de infertilidad y sin historia de vacunación contra IBR, pertenecientes a 32 fincas distribuidas en el municipio de Montería. adicionalmente, se obtuvieron muestras al azar de 20 toros pertenecientes a las mismas fincas. Se analizaron anticuerpos contra IBR mediante la prueba de ELISA. Resultados. Los resultados mostraron una seroprevalencia de 74.7 por ciento para rinotraqueitis infecciosa bovina. Seencontraron diferencias significativas en cuanto a prevalencía para las variables sexo y edad de los animales (p<0.05). No hubo diferencias significativas en prevalencía para las variables raza, zona, tipo de explotación y alteraciones reproductivas (p>0.05). Conclusión. La alta prevalencia de la infección por IBR en vacas podrían correlacionarse con la infección en toros, lo cual tiene un significado relevante, ya que la infección es de transmisión venérea. Estos resultados deben alertar a las autoridades sanitarias para que implementen estrategias de prevención y control

Objective. To study the seroprevalence of IBR in livestock bovine with infertility antecedents. Materials and methods. Blood samples were collected from 150 animals with infertility antecedents and nonvaccinated history against IBR, belonging to 32 farms in Monteria municipality and samples at random of 20 bulls belonging to the same farms. Antibodies were analyzed against IBR by using ELISA test. Results. The results showed a seroprevalence of 74.7% for bovine rhinotracheitis infectious. They were significant differences with regard to prevalence for sex and age variables of animals (p<0.05). There were not significant differences in prevalence for the variable race, area, type of exploitation and reproductive alterations (p>0.05). Conclusion. The high prevalence of the infection for IBR in cows could be associated with the infection in bulls, which has an outstanding meaning, since the infection is of venereal transmission. These results should alert to sanitary authorities in order to implement prevention and control strategies.

Spatial hierarchical variances and age covariances for seroprevalence to Leptospira interrogans serovar hardjo, BoHV-1 and BVDV for cattle in the State of Paraíba, Brazil.

We estimated spatial hierarchal variances and age-group covariances for seroprevalence to Leptospira interrogans serovar hardjo (LeptoH), bovine viral-diarrhea virus (BVDV) and bovine herpesvirus type 1 (BoHV-1) among 2343 cattle from 72 properties sampled in the State of Paraíba, Brazil in 2000. From each property, eight animals in each of the four age categories were evaluated. The age categories studied were: pre-weaned (0-6 months), young (7-18 months), replacement (19-30 months) and mature (>30 months). Overall seroprevalence to LeptoH was 16.0% and showed clustering at all levels of the spatial hierarchy and had a high posterior probability of being negatively correlated between replacement and mature groups within herds. Seroprevalence to BoHV-1 was 46.6% and demonstrated very little clustering among levels of the spatial hierarchy and was positively correlated between young and replacement groups within herds. Seroprevalence to BVD was 22.2% and was strongly clustered within herds and was positively correlated between young and replacement age groups within herds.

Seroprevalence of and risk factors for infectious bovine rhinotracheitis in beef cattle herds of Yucatan, Mexico.

The main objective of this cross-sectional study was to estimate the seroprevalence of infectious bovine rhinotracheitis (IBR) in a population of non-vaccinated beef cattle in the livestock region of Yucatan, Mexico and to determine potential risk factors related to the seroprevalence. Also, we estimated the intraherd correlation (r(e)) and design effect (D) of IBR seropositivity. Cattle were selected by two-stage cluster sampling. Blood samples were collected from 564 animals from 35 herds. Sera were tested for antibodies against IBR using the serum-neutralisation test. Information regarding the herd and each animal sampled were recorded through a personal interview with the farmer or farm manager. The data were analysed using fixed-effects logistic multiple regression. Thirty-four of the 35 herds had at least one seropositive animal. The animal true seroprevalence was 54.4%. Animals in large herds or in production had higher odds of seropositivity than those in small herds or growing. The r(e) and D were 0.17 and 3.62, respectively.

Prevalência de anticorpos neutralizantes contra o herpesvírus bovino tipo 1, decorrente de infecçäo natural, em rebanhos com distúrbios reprodutivos / Prevalence of neutralizing antibodies against bovine herpesvirus type 1, due natural infection, in herds with reproductive problems

A detecçäo de anticorpos anti-Herpesvírus Bovino tipo 1 (BHV-1) foi realizada, através da técnica de soroneutralizaçäo, em 1235 amostras de soro de bovinos adultos, näo vacinados contra Rinotraqueíte Infecciosa Bovina. As amostras de soro analisadas foram colhidas em 81 rebanhos, com histórico de problemas reprodutivos, incluindo animais com aptidäo para carne e leite, provenientes de 30 municípios do Estado do Paraná. Na amostragem proveniente de rebanhos leiteiros, 41,9 por cento (409/977) das amostras de soro e 90,5 por cento (57/63) dos rebanhos foram considerados positivos. Em bovinos de corte, o índice de soropositividade foi de 50,8 por cento (131/258) e 100 por cento (18/18) para amostras de soro e rebanhos, respectivamente. As frequências de 43,7 por cento (540/1235) de animais e 92,6 por cento (75/81) de rebanhos soropositivos demonstram que as infecçöes por BHV-1 apresentam-se amplamente disseminadas nas regiöes estudadas.

Erradicação do herpesvírus bovino - 1 (BHV-1) de um rebanho bovino leiteiro em manejo semi-intensivo / Eradication of Herpesvirus Bovine-1 (BHV-1) from a dairy cattle herd with a semi-intensive management

Com o objetivo de erradicar o BHV-1 de um rebanho bovino leiteiro de alto valor genético sem a utilização de vacina, foi realizado um exame sorológico prévio em 154 animais, onde constatou-se 15,6% de reagentes ao BHV-1. A técnica utilizada foi a soroneutralização em microplacas. Dentre os animais soropositivos, as vacas vazias foram descartadas imediatamente e as prenhes isoladas e descartadas após o parto. Os bezerros apresentaram anticorpos colostrais até os seis meses de idade, motivo pelo qual não foram descartados; nos bezerros de 6 a 12 meses de idade e nas novilhas não foram diagnosticados animais soropositivos. Os animais foram examinados trimestralmente, por 21 meses, seguido de mais duas coletas semestrais. As vacas secas, prenhes e em lactação, soropositivas, revelaram ser a fonte de infecção do BHV-1. A manutenção de rebanho livre é possível, desde que sejam adotadas medidas como a utilização de sêmen livre de BHV-1, realização de quarentena no ingresso de animais e exames sorológicos anuais visando impedir a reintrodução do vírus. Com o conjunto destas medidas adotadas, a fazenda encontra-se há 18 meses livre do BHV-1