PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

ABSTRACT.- Costa E.A., Bastianetto E., Vasconcelos A.C., Bomfim M.R.Q., Fonseca F.G., Gomes A.D., Leite R.C. & Resende M. 2009. An outbreak of malignant catarrhal fever in Murrah buffaloes in Minas Gerais, Brazil. Pesquisa Veterinária Brasileira 29(5):395-400. Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, MG 31270-901, Brazil. E-mail: lvc@icb.ufmg.br An outbreak of Malignant Catarrhal Fever (MCF) resulted in death of five female buffaloes and one domestic cow from the same farm. Four buffaloes died 10-15 days after the appearance of clinical signs, while the fifth was euthanized in extremis, after similar clinical signs. Histopathological lesions included multifocal histiolymphocytic epicarditis, myocarditis and lymphocytic interstitial pneumonia, which are commonly seen in cases of MCF in buffaloes. Furthermore, lymphocytic vasculitis centered in the adventitia, with occasional fibrinoid necrosis in the muscular layer, was found in the kidneys, liver, spleen, lymph nodes and brain. Nucleotide sequencing of DNA fragments from the central nervous system amplified by PCR revealed 98% similarity with known OHV-2 sequences from Genbank. Additionally, PCR analysis also revealed the presence of OHV-2 DNA in the peripheral mononuclear blood cells of two clinically healthy buffaloes. The diagnosis of MCF was based on epidemiological, clinical, gross and histopathological findings and on the results of a semi-nested PCR followed by nucleotide sequencing.

• Diseases of buffaloes doenças de búfalos gammaherpesviruses gammaherpesvirus malignant catarrhal fever

Abstract in Portuguese:

ABSTRACT.- Costa E.A., Bastianetto E., Vasconcelos A.C., Bomfim M.R.Q., Fonseca F.G., Gomes A.D., Leite R.C. & Resende M. 2009. An outbreak of malignant catarrhal fever in Murrah buffaloes in Minas Gerais, Brazil. Pesquisa Veterinária Brasileira 29(5):395-400. Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, MG 31270-901, Brazil. E-mail: lvc@icb.ufmg.br An outbreak of Malignant Catarrhal Fever (MCF) resulted in death of five female buffaloes and one domestic cow from the same farm. Four buffaloes died 10-15 days after the appearance of clinical signs, while the fifth was euthanized in extremis, after similar clinical signs. Histopathological lesions included multifocal histiolymphocytic epicarditis, myocarditis and lymphocytic interstitial pneumonia, which are commonly seen in cases of MCF in buffaloes. Furthermore, lymphocytic vasculitis centered in the adventitia, with occasional fibrinoid necrosis in the muscular layer, was found in the kidneys, liver, spleen, lymph nodes and brain. Nucleotide sequencing of DNA fragments from the central nervous system amplified by PCR revealed 98% similarity with known OHV-2 sequences from Genbank. Additionally, PCR analysis also revealed the presence of OHV-2 DNA in the peripheral mononuclear blood cells of two clinically healthy buffaloes. The diagnosis of MCF was based on epidemiological, clinical, gross and histopathological findings and on the results of a semi-nested PCR followed by nucleotide sequencing.

Abstract in English:

Abstract.- Oliveira E.C., Pescador C.A., Sonne L., Pavarini S.P., Santos A.S., Corbellini L.G. & Driemeier D. 2009. [Immunohistochemical analysis of dogs infected naturally by canine parvovirus.] Análise imuno-histoquímica de cães naturalmente infectados pelo parvovírus canino. Pesquisa Veterinária Brasileira 29(2):131-136. Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br Ninety-six dogs with gross lesions suggestive of canine parvovirus infection were selected and necropsied in the Faculty of Veterinary Medicine, Universidade Federal do Rio Grande do Sul, between March 2005 and November 2006. The main gross lesions were enlargement of the Peyer’s patches in the small intestine and hyperemia in the intestinal mucosa and serosa. Microscopically, the small intestine showed necrotizing enteritis in 77% (74/96) of the dogs examined. However, in 17.7% of the histological evaluation in the small intestine were damaged due to autolytic changes making it difficult to obtain an appropriate interpretation. The immunohistochemistry test was performed in tissues of small intestine, mesenteric lymph nodes, thymus, spleen, tonsils, tongue, and bone marrow in all the 96 selected cases. Parvovirus antigen was detected in 91.6% (88/96) of the dogs necropsied. The best result of the IHC test was seen in samples of small intestine which was positive in 77% (74/96) of the cases. The statistical analysis (Fisher test) showed a weak association between intestinal autolysis and positive result of the IHC test. The chance of the autolysed intestine showing a positive result in the immunohistochemistry test was 0.33 less (OR=0.33, 95% CI:0.10-1.17) when compared with small intestine not autolysed.

• Canine parvovirus dogs immunohistochemistry small intestine lymphoid tissue

Abstract in Portuguese:

Abstract.- Oliveira E.C., Pescador C.A., Sonne L., Pavarini S.P., Santos A.S., Corbellini L.G. & Driemeier D. 2009. [Immunohistochemical analysis of dogs infected naturally by canine parvovirus.] Análise imuno-histoquímica de cães naturalmente infectados pelo parvovírus canino. Pesquisa Veterinária Brasileira 29(2):131-136. Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br Ninety-six dogs with gross lesions suggestive of canine parvovirus infection were selected and necropsied in the Faculty of Veterinary Medicine, Universidade Federal do Rio Grande do Sul, between March 2005 and November 2006. The main gross lesions were enlargement of the Peyer’s patches in the small intestine and hyperemia in the intestinal mucosa and serosa. Microscopically, the small intestine showed necrotizing enteritis in 77% (74/96) of the dogs examined. However, in 17.7% of the histological evaluation in the small intestine were damaged due to autolytic changes making it difficult to obtain an appropriate interpretation. The immunohistochemistry test was performed in tissues of small intestine, mesenteric lymph nodes, thymus, spleen, tonsils, tongue, and bone marrow in all the 96 selected cases. Parvovirus antigen was detected in 91.6% (88/96) of the dogs necropsied. The best result of the IHC test was seen in samples of small intestine which was positive in 77% (74/96) of the cases. The statistical analysis (Fisher test) showed a weak association between intestinal autolysis and positive result of the IHC test. The chance of the autolysed intestine showing a positive result in the immunohistochemistry test was 0.33 less (OR=0.33, 95% CI:0.10-1.17) when compared with small intestine not autolysed.

Abstract in English:

Abstract.- Sonne L., Oliveira E.C., Pescador C.A., Santos A.S., Pavarini S. P., Carissimi A.S. & Driemeier D. 2009. [Pathologic and immunohistochemistry findings in dogs naturally infected by canine distemper virus.] Achados patológicos e imuno-histoquímicos em cães infectados naturalmente pelo vírus da cinomose canina. Pesquisa Veterinária Brasileira 29(2):143-149. Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br Canine distemper is a viral disease that affects mainly respiratory, gastrointestinal and nervous system. The present study analyzes pathologic and immunohistochemical findings in 54 dogs with canine distemper of a total of 760 canine necropsies performed from July 2006 to October 2007. The gross lesions were characterized by mucopurulent oculonasal discharge, hyperkeratosis of footpads, red and not collapsed lungs, thymic atrophy, watery intestinal content, hyperemia and enlarged Peyer’s patches. The histological findings were characterized by interstitial pneumonia, lymphoid depletion, white matter demyelization, perivascular cuffs and intracytoplasmatic and intranuclear inclusion bodies located in epithelial cells of gastric mucosa, urinary bladder, bronchial, renal pelvis, footpads, eyelid, skin of the ear, tonsil, central nervous system and mononuclear cells in lymph nodes, spleen, and tonsils. Viral antigen was detected by an immunohistochemical procedure using a mouse monoclonal anti-canine distemper antibody. The footpads were the more constantly (67.4% of the cases) immunolabeled tissue, followed by stomach with 62.7%. Immunohistochemistry was demonstrated to be a useful tool for the study of viral antigen distribution in distemper affected dogs as well as it indicated which is the best tissue to be examined in order to confirm a suspected case of canine.

• Canine diseases distemper immunohistochemistry

Abstract in Portuguese:

Abstract.- Sonne L., Oliveira E.C., Pescador C.A., Santos A.S., Pavarini S. P., Carissimi A.S. & Driemeier D. 2009. [Pathologic and immunohistochemistry findings in dogs naturally infected by canine distemper virus.] Achados patológicos e imuno-histoquímicos em cães infectados naturalmente pelo vírus da cinomose canina. Pesquisa Veterinária Brasileira 29(2):143-149. Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br Canine distemper is a viral disease that affects mainly respiratory, gastrointestinal and nervous system. The present study analyzes pathologic and immunohistochemical findings in 54 dogs with canine distemper of a total of 760 canine necropsies performed from July 2006 to October 2007. The gross lesions were characterized by mucopurulent oculonasal discharge, hyperkeratosis of footpads, red and not collapsed lungs, thymic atrophy, watery intestinal content, hyperemia and enlarged Peyer’s patches. The histological findings were characterized by interstitial pneumonia, lymphoid depletion, white matter demyelization, perivascular cuffs and intracytoplasmatic and intranuclear inclusion bodies located in epithelial cells of gastric mucosa, urinary bladder, bronchial, renal pelvis, footpads, eyelid, skin of the ear, tonsil, central nervous system and mononuclear cells in lymph nodes, spleen, and tonsils. Viral antigen was detected by an immunohistochemical procedure using a mouse monoclonal anti-canine distemper antibody. The footpads were the more constantly (67.4% of the cases) immunolabeled tissue, followed by stomach with 62.7%. Immunohistochemistry was demonstrated to be a useful tool for the study of viral antigen distribution in distemper affected dogs as well as it indicated which is the best tissue to be examined in order to confirm a suspected case of canine.

Abstract in English:

ABSTRACT.- Flores E.F., Weiblen R, Vogel F.S.F., Dezengrini R., Almeida S.R., Spilki F.R. & Roehe P.M. 2009. [Experimental neuropathogenesis of bovine herpesvirus 5 infection in rabbits.] Neuropatogênese experimental da infecção pelo herpesvírus bovino tipo 5 em coelhos. Pesquisa Veterinária Brasileira 29(1):1-16. Departamento de Medicina Veterinária Preventiva. Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS. Brazil. E-mail: eduardofurtadoflores@gmail.com Several aspects of the biology of bovine herpesvirus 5 (BoHV-5) have been studied in rabbits, which develop acute infection and neurological disease upon experimental inoculation. The acute infection is followed by the establishment of latent infection, which can be naturally or artificially reactivated. The first experiments in rabbits established a protocol for virus inoculation and monitoring the infection, and characterized the main virological, clinical and pathological aspects of the acute infection. The pathogenesis of acute infection, from the initial viral replication at site of inoculation, pathways and kinetics of viral transport to the brain, distribution and virus replication in the central nervous system (CNS), cellular and tissue tropism, clinical signs and CNS pathology have been extensively studied using this animal model. Subsequently, several biological and molecular aspects of latent BoHV-5 infection have also been elucidated upon inoculation of rabbits. Rabbits have also been used to investigate the phenotype (neuroinvasiveness, neurogrowth) of field isolates and recombinant vaccine candidates, protection by passive immunity, vaccine protection, the efficacy of anti-viral drugs and support therapies for neurological disease. This animal model was also used to investigate the origin and distribution of electric impulses involved in seizures - a hallmark of BoHV-5 induced neurological infection - and also to test the efficacy of anti-convulsivants. In spite of the possible differences between rabbits and cattle - the natural host of the virus - the observations taken from this experimental model have greatly contributed to the knowledge of the biology of BoHV-5 infection. The present article presents a review of the main published and unpublished results and observations by our group, comprising more than a decade of studies on the pathogenesis of BoHV-5 infection in the rabbit model.

• Bovine herpesvirus 5 BoHV-5 rabbits experimental model

Abstract in Portuguese:

ABSTRACT.- Flores E.F., Weiblen R, Vogel F.S.F., Dezengrini R., Almeida S.R., Spilki F.R. & Roehe P.M. 2009. [Experimental neuropathogenesis of bovine herpesvirus 5 infection in rabbits.] Neuropatogênese experimental da infecção pelo herpesvírus bovino tipo 5 em coelhos. Pesquisa Veterinária Brasileira 29(1):1-16. Departamento de Medicina Veterinária Preventiva. Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS. Brazil. E-mail: eduardofurtadoflores@gmail.com Several aspects of the biology of bovine herpesvirus 5 (BoHV-5) have been studied in rabbits, which develop acute infection and neurological disease upon experimental inoculation. The acute infection is followed by the establishment of latent infection, which can be naturally or artificially reactivated. The first experiments in rabbits established a protocol for virus inoculation and monitoring the infection, and characterized the main virological, clinical and pathological aspects of the acute infection. The pathogenesis of acute infection, from the initial viral replication at site of inoculation, pathways and kinetics of viral transport to the brain, distribution and virus replication in the central nervous system (CNS), cellular and tissue tropism, clinical signs and CNS pathology have been extensively studied using this animal model. Subsequently, several biological and molecular aspects of latent BoHV-5 infection have also been elucidated upon inoculation of rabbits. Rabbits have also been used to investigate the phenotype (neuroinvasiveness, neurogrowth) of field isolates and recombinant vaccine candidates, protection by passive immunity, vaccine protection, the efficacy of anti-viral drugs and support therapies for neurological disease. This animal model was also used to investigate the origin and distribution of electric impulses involved in seizures - a hallmark of BoHV-5 induced neurological infection - and also to test the efficacy of anti-convulsivants. In spite of the possible differences between rabbits and cattle - the natural host of the virus - the observations taken from this experimental model have greatly contributed to the knowledge of the biology of BoHV-5 infection. The present article presents a review of the main published and unpublished results and observations by our group, comprising more than a decade of studies on the pathogenesis of BoHV-5 infection in the rabbit model.

Abstract in English:

ABSTRACT.- Claus M.P., Lunardi M., Alfieri A.F., Sartori D., Fungaro M.H.P & Alfieri A.A. 2009. Identification of the recently described new type of bovine papillomavirus (BPV-8) in a Brazilian beef cattle herd. Pesquisa Veterinária Brasileira 29(1):25-28. Laboratório de Virologia Animal, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Agrárias, Universidade Estadual de Londrina, Cx. Postal 6001, Campus Universitário, Londrina, PR 86051-990, Brazil. E-mail: alfieri@uel.br Bovine papillomavirus type 8 (BPV-8) was first detected and described in teat warts as well as in healthy teat skin from cattle raised in Japan. The entire viral genome was sequenced in 2007. Additionally, a variant of BPV-8, BPV-8-EB, was also identified from papillomatous lesions of a European bison in Slovakia. In Brazil, despite the relatively common occurrence of BPV infections, the identification and determination of viral types present in cattle is still sporadic. The aim of this study is to report the occurrence of the recently described BPV-8 in Brazil. The virus was identified in a skin warts obtained from a beef cattle herd located in Parana state, southern Brazil. The papilloma had a macular, non-verrucous gross aspect and was located on the dorsal thorax of a cow. Polymerase chain reaction (PCR) was performed using generic primers for partial amplification of L1 gene. The obtained amplicon (480bp) was cloned and two selected clones were sequenced. The nucleotide sequence was compared to existing papillomaviral genomic sequences, identifying the virus as BPV type 8. This study represents the first report of BPV-8 occurrence in Brazil, what suggests its presence among Brazilian cattle.

• Bovine bovine papillomavirus type 8 BPV-8 cutaneous papillomatosis molecular analysis

Abstract in Portuguese:

ABSTRACT.- Claus M.P., Lunardi M., Alfieri A.F., Sartori D., Fungaro M.H.P & Alfieri A.A. 2009. Identification of the recently described new type of bovine papillomavirus (BPV-8) in a Brazilian beef cattle herd. Pesquisa Veterinária Brasileira 29(1):25-28. Laboratório de Virologia Animal, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Agrárias, Universidade Estadual de Londrina, Cx. Postal 6001, Campus Universitário, Londrina, PR 86051-990, Brazil. E-mail: alfieri@uel.br Bovine papillomavirus type 8 (BPV-8) was first detected and described in teat warts as well as in healthy teat skin from cattle raised in Japan. The entire viral genome was sequenced in 2007. Additionally, a variant of BPV-8, BPV-8-EB, was also identified from papillomatous lesions of a European bison in Slovakia. In Brazil, despite the relatively common occurrence of BPV infections, the identification and determination of viral types present in cattle is still sporadic. The aim of this study is to report the occurrence of the recently described BPV-8 in Brazil. The virus was identified in a skin warts obtained from a beef cattle herd located in Parana state, southern Brazil. The papilloma had a macular, non-verrucous gross aspect and was located on the dorsal thorax of a cow. Polymerase chain reaction (PCR) was performed using generic primers for partial amplification of L1 gene. The obtained amplicon (480bp) was cloned and two selected clones were sequenced. The nucleotide sequence was compared to existing papillomaviral genomic sequences, identifying the virus as BPV type 8. This study represents the first report of BPV-8 occurrence in Brazil, what suggests its presence among Brazilian cattle.

Abstract in English:

ABSTRACT.- Ståhl K., Benito A., Felmer R., Zuñiga J., Reinhardt G., Rivera H., Baule C. & Moreno-López J. 2009. Genetic diversity of bovine viral diarrhoea virus (BVDV) from Peru and Chile. Pesquisa Veterinária Brasileira 29(1):41-44. Joint Virology Research and Development Division, National Veterinary Institute and Swedish University of Agricultural Sciences Uppsala, Sweden. E-mail: Karl.Stahl@bvf.slu.se Twenty-five BVDV strains, detected in serum from persistently infected cattle from Peru (n=15) and Chile (n=10) were genetically characterized. The phylogenetic analysis based on the 5’ UTR showed that all 25 strains belonged to genotype 1. Twenty-three of the strains could further be subdivided into subtype 1b, and two out of ten Chilean strains into subtype 1a. In conclusion, in total 23 out of 25 strains analyzed were of genotype 1, subtype 1b. This is the predominant BVDV subtype in many countries all over the world, including USA. The close homology with previously described strains reflects the influence of livestock trade on the diversity of BVDV circulating within and between countries and continents. Peru and Chile have imported large numbers of cattle from USA and Europe, mostly with insufficient or lacking health documentation.

• Bovine viral diarrhoea virus BVDV diversity pestivirus phylogenetic analysis

Abstract in Portuguese:

ABSTRACT.- Ståhl K., Benito A., Felmer R., Zuñiga J., Reinhardt G., Rivera H., Baule C. & Moreno-López J. 2009. Genetic diversity of bovine viral diarrhoea virus (BVDV) from Peru and Chile. Pesquisa Veterinária Brasileira 29(1):41-44. Joint Virology Research and Development Division, National Veterinary Institute and Swedish University of Agricultural Sciences Uppsala, Sweden. E-mail: Karl.Stahl@bvf.slu.se Twenty-five BVDV strains, detected in serum from persistently infected cattle from Peru (n=15) and Chile (n=10) were genetically characterized. The phylogenetic analysis based on the 5’ UTR showed that all 25 strains belonged to genotype 1. Twenty-three of the strains could further be subdivided into subtype 1b, and two out of ten Chilean strains into subtype 1a. In conclusion, in total 23 out of 25 strains analyzed were of genotype 1, subtype 1b. This is the predominant BVDV subtype in many countries all over the world, including USA. The close homology with previously described strains reflects the influence of livestock trade on the diversity of BVDV circulating within and between countries and continents. Peru and Chile have imported large numbers of cattle from USA and Europe, mostly with insufficient or lacking health documentation.

Abstract in English:

ABSTRACT.- Silva Júnior A., Castro L.A., Chiarelli Neto O., Silva F.M.F., Vidigal P.M.P., Moraes M.P. & Almeida M.R. 2009. Development and evaluation of a recombinant DNA vaccine candidate expressing porcine circovirus 2 structural protein. Pesquisa Veterinária Brasileira 29(1):76-82. Laboratório de Infectologia Molecular Animal, Instituto de Biotecnologia Aplicada à Agropecuária, Universidade Federal de Viçosa, Av. PH Rolfs s/n, Campus Universitário, Viçosa, MG 36570-000, Brazil. E-mail: marcia@ufv.br Porcine circovirus 2 (PCV2) is generally associated with the porcine circovirosis syndrome, which is considered an important disease of swine and has potentially serious economic impact on the swine industry worldwide. This article describes the construction of a recombinant plasmid expressing the PCV2 structural protein and the evaluation of cellular and humoral immune responses produced by this recombinant vaccine in BALB/c mice. The vaccine candidate was obtained and analyzed in vivo, in an effort to determine the ability to induce a specific immune response in mice. DNA was extracted from a Brazilian PCV2 isolate and the gene coding for Cap protein was amplified by PCR and inserted into an expression plasmid. Groups of BALB/c mice were inoculated intra-muscularly and intradermally in a 15-day interval, with 100 µg and 50 µg of the vaccine construct, respectively. Another group was inoculated intramuscularly with 100 µg of empty plasmid, corresponding to the control group. Seroconversion and cellular response in BALB/c mice were compared and used for vaccine evaluation. Seroconversion was analyzed by ELISA. After a series of 3 immunizations the spleen cells of the immunized animals were used to perform lymphocyte proliferation assays. Seroconversion to PCV2 was detected by ELISA in the animals inoculated with the vaccine construct when compared with control groups. Lymphocyte proliferation assays showed a stronger cell proliferation in the inoculated animals compared with the control group. Thus, the vaccine candidate construct demonstrated to be able to induce both humoral and cellular responses in inoculated mice.

• PCV2 DNA vaccine porcine circovirosis

Abstract in Portuguese:

ABSTRACT.- Silva Júnior A., Castro L.A., Chiarelli Neto O., Silva F.M.F., Vidigal P.M.P., Moraes M.P. & Almeida M.R. 2009. Development and evaluation of a recombinant DNA vaccine candidate expressing porcine circovirus 2 structural protein. Pesquisa Veterinária Brasileira 29(1):76-82. Laboratório de Infectologia Molecular Animal, Instituto de Biotecnologia Aplicada à Agropecuária, Universidade Federal de Viçosa, Av. PH Rolfs s/n, Campus Universitário, Viçosa, MG 36570-000, Brazil. E-mail: marcia@ufv.br Porcine circovirus 2 (PCV2) is generally associated with the porcine circovirosis syndrome, which is considered an important disease of swine and has potentially serious economic impact on the swine industry worldwide. This article describes the construction of a recombinant plasmid expressing the PCV2 structural protein and the evaluation of cellular and humoral immune responses produced by this recombinant vaccine in BALB/c mice. The vaccine candidate was obtained and analyzed in vivo, in an effort to determine the ability to induce a specific immune response in mice. DNA was extracted from a Brazilian PCV2 isolate and the gene coding for Cap protein was amplified by PCR and inserted into an expression plasmid. Groups of BALB/c mice were inoculated intra-muscularly and intradermally in a 15-day interval, with 100 µg and 50 µg of the vaccine construct, respectively. Another group was inoculated intramuscularly with 100 µg of empty plasmid, corresponding to the control group. Seroconversion and cellular response in BALB/c mice were compared and used for vaccine evaluation. Seroconversion was analyzed by ELISA. After a series of 3 immunizations the spleen cells of the immunized animals were used to perform lymphocyte proliferation assays. Seroconversion to PCV2 was detected by ELISA in the animals inoculated with the vaccine construct when compared with control groups. Lymphocyte proliferation assays showed a stronger cell proliferation in the inoculated animals compared with the control group. Thus, the vaccine candidate construct demonstrated to be able to induce both humoral and cellular responses in inoculated mice.

Abstract in English:

ABSTRACT.- Diéguez F.J., Yus E., Sanjuán M.L., Vilar M.J. & Arnaiz I. 2008. Monitoring bovine viral diarrhea virus (BVDV) infection status in dairy herds. Pesquisa Veterinária Brasileira 28(12):588-592. Unidad de Epidemiología y Sanidad Animal, Instituto de Investigación y Análisis Alimentarios, Facultad de Veterinaria s/n, Lugo 27002, Spain. E-mail: franciscojavier.dieguez@usc.es This study was designed to assess the relationship between antibodies against bovine viral diarrhea virus (BVDV) determined in the bulk tank milk (BTM) and the within-herd seroprevalence. We also assessed the efficiency of measuring antibody levels in BTM samples to monitor BVDV infection status in a herd. In the 81 farms included in the study, BTM samples were obtained and blood samples withdrawn from all cattle older than one year. The infection status was then determined in serum and milk using a commercial blocking ELISA based on the detection of anti-p80 antibodies. Apart from these baseline serum and milk samples, another BTM sample was collected from each herd 9 months later, and a third BTM sample obtained 9 months after this. In these second and third milk samples, anti-BVDV antibodies were determined using the same ELISA kit. Statistical tests revealed good agreement between herd seroprevalences (% seropositive animals in the herd) and the antibody levels detected in the BTM samples. During the 18 months of follow-up, the farms with persistently infected cattle at the study outset (14.8% of the herds) showed a significant decrease in BTM antibody titers after virus clearance. Conversely, a significant increase in BTM antibody levels was observed in the herds infected with BVDV during the follow-up period. Our findings indicate that monitoring antibody levels in the BTM is a useful method of identifying changes in the BVDV infection status of a herd.

• Bovine viral diarrhea vírus BVDV antibodies diagnostic milk

Abstract in Portuguese:

ABSTRACT.- Diéguez F.J., Yus E., Sanjuán M.L., Vilar M.J. & Arnaiz I. 2008. Monitoring bovine viral diarrhea virus (BVDV) infection status in dairy herds. Pesquisa Veterinária Brasileira 28(12):588-592. Unidad de Epidemiología y Sanidad Animal, Instituto de Investigación y Análisis Alimentarios, Facultad de Veterinaria s/n, Lugo 27002, Spain. E-mail: franciscojavier.dieguez@usc.es This study was designed to assess the relationship between antibodies against bovine viral diarrhea virus (BVDV) determined in the bulk tank milk (BTM) and the within-herd seroprevalence. We also assessed the efficiency of measuring antibody levels in BTM samples to monitor BVDV infection status in a herd. In the 81 farms included in the study, BTM samples were obtained and blood samples withdrawn from all cattle older than one year. The infection status was then determined in serum and milk using a commercial blocking ELISA based on the detection of anti-p80 antibodies. Apart from these baseline serum and milk samples, another BTM sample was collected from each herd 9 months later, and a third BTM sample obtained 9 months after this. In these second and third milk samples, anti-BVDV antibodies were determined using the same ELISA kit. Statistical tests revealed good agreement between herd seroprevalences (% seropositive animals in the herd) and the antibody levels detected in the BTM samples. During the 18 months of follow-up, the farms with persistently infected cattle at the study outset (14.8% of the herds) showed a significant decrease in BTM antibody titers after virus clearance. Conversely, a significant increase in BTM antibody levels was observed in the herds infected with BVDV during the follow-up period. Our findings indicate that monitoring antibody levels in the BTM is a useful method of identifying changes in the BVDV infection status of a herd.

Abstract in English:

Abstract.- Pavarini S.P., Bezerra Junior P.S., Santos A.S., Pescador C.A. & Driemeier D. 2008. [Clinic pathological features during a winter dysentery outbreak in cattle in Rio Grande do Sul.] Achados clínico patológicos durante um surto de disenteria de inverno em bovinos no Rio Grande do Sul. Pesquisa Veterinária Brasileira 28(12):611- 616. Departamento de Patologia Clínica Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br The report describes a winter dysentery outbreak that affected 10 dairy cows from a ranch located in the county of Viamão, Rio Grande do Sul. The most significant clinical sign was profuse and watery diarrhea, which ranged from a greenish to a brownish coloration and from occasional blood streaks with mucus to a bloody diarrhea. Most cases persisted for 5 days and also included depression, drastic decrease in milk production and in food consumption. Only one of the affected animals died. The necropsy revealed pale mucosa and sanguineous content with high quantity of blood clots, particularly within the spiral colon, and petechiae on the colonic mucosa. Histopathological lesions were predominant in the spiral colon, and consisted of a high number of dilated crypts without epithelium or with the replacement of a pavement epithelium with occasional immature cuboidal cells, which sometimes showed enlarged nucleus and proeminent nucleolus. Some crypts were filled with epithelial desquamation and polymorphnuclear cells. Bovine coronavirus (8F2) monoclonal antibody was used for immunohistochemistry on sections of the spiral colon that showed positive reactions in the cytoplasm of the infected crypt epithelium, sloughed necrotic cells, and within macrophages in the lamina propria of both.

• Winter dysentery diarrhea spiral colon bovine coronavirus

Abstract in Portuguese:

Abstract.- Pavarini S.P., Bezerra Junior P.S., Santos A.S., Pescador C.A. & Driemeier D. 2008. [Clinic pathological features during a winter dysentery outbreak in cattle in Rio Grande do Sul.] Achados clínico patológicos durante um surto de disenteria de inverno em bovinos no Rio Grande do Sul. Pesquisa Veterinária Brasileira 28(12):611- 616. Departamento de Patologia Clínica Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br The report describes a winter dysentery outbreak that affected 10 dairy cows from a ranch located in the county of Viamão, Rio Grande do Sul. The most significant clinical sign was profuse and watery diarrhea, which ranged from a greenish to a brownish coloration and from occasional blood streaks with mucus to a bloody diarrhea. Most cases persisted for 5 days and also included depression, drastic decrease in milk production and in food consumption. Only one of the affected animals died. The necropsy revealed pale mucosa and sanguineous content with high quantity of blood clots, particularly within the spiral colon, and petechiae on the colonic mucosa. Histopathological lesions were predominant in the spiral colon, and consisted of a high number of dilated crypts without epithelium or with the replacement of a pavement epithelium with occasional immature cuboidal cells, which sometimes showed enlarged nucleus and proeminent nucleolus. Some crypts were filled with epithelial desquamation and polymorphnuclear cells. Bovine coronavirus (8F2) monoclonal antibody was used for immunohistochemistry on sections of the spiral colon that showed positive reactions in the cytoplasm of the infected crypt epithelium, sloughed necrotic cells, and within macrophages in the lamina propria of both.

Abstract in English:

ABSTRACT.- Arenhart S., Silva L.F., Henzel A., Ferreira R., Weiblen R. & Flores E.F. 2008. [Fetal protection against bovine viral diarrhea virus (BVDV) in pregnant cows previously immunized with an experimental attenuated vaccine.] Proteção fetal contra o vírus da diarréia viral bovina (BVDV) em vacas prenhes previamente imunizadas com uma vacina experimental atenuada. Pesquisa Veterinária Brasileira 28(10):461-470. Departamento de Medicina Veterinária, Centro de Ciências Rurais, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil. E-mail: flores@ccr.ufsm.br This paper reports the antibody response and fetal protection in pregnant cows conferred by an experimental vaccine containing two attenuated strains of bovine viral diarrhea virus (BVDV-1 and BVDV-2). Cows (n=19) were vaccinated twice, with a 34-days-interval, with the experimental vaccine and together with non-vaccinated controls (n=18), were mated and challenged between days 60 and 90 of gestation by intranasal inoculation of four heterologous BVDV-1 and BVDV-2 isolates. The antibody response was evaluated by serum-neutralization tests performed at different intervals after vaccination (days 34, 78 and 138 post-vaccination [pv]). Fetal protection was monitored by ultrassonographic and clinical examination of the dams and fetuses during the rest of gestation; and through virological and serological examination of pre-colostral blood obtained from aborted and/or recently born fetuses/calves. At the day of challenge (day 138 pv), all vaccinated cows had neutralizing antibodies in high titers against BVDV-1 (1,280- ³10,240), and with one exception (titer 20), presented moderate to high titers to BVDV-2 (80-1,280). At the end of the monitoring, only three out of 18 control cows (16.6%) delivered healthy, virus-free calves. Fifteen non-vaccinated cows (83.3%) presented signs of fetal infection and/or had reproductive losses. Seven of these cows (38.8%) delivered virus-positive calves; five were healthy and survived (27.7%); two were premature or weak and lasted three and 15 days, respectively. The other eight cows (44.4%) aborted between day 30 post-challenge and the parturition; or delivered premature or stillbirth calves. In contrast, 17 out of 19 (89.4%) vaccinated cows delivery virus-free, healthy calves. One vaccinated cow aborted around day 130 post-challenge, yet this fetus could not be examined for the presence of virus. Another cow delivered a virus-positive calf (5.2%). In summary, the experimental vaccine induced adequate antibody titers in most animals and the immunological response induced by vaccination was able to prevent fetal infection and reproductive losses upon challenge with a pool of heterologous BVDV isolates. Hence, this experimental vaccine may be an attractive alternative for the prevention of reproductive losses associated with BVDV infection.

• Bovine viral diarrhea virus BVDV experimental vaccine fetal protection

Abstract in Portuguese:

ABSTRACT.- Arenhart S., Silva L.F., Henzel A., Ferreira R., Weiblen R. & Flores E.F. 2008. [Fetal protection against bovine viral diarrhea virus (BVDV) in pregnant cows previously immunized with an experimental attenuated vaccine.] Proteção fetal contra o vírus da diarréia viral bovina (BVDV) em vacas prenhes previamente imunizadas com uma vacina experimental atenuada. Pesquisa Veterinária Brasileira 28(10):461-470. Departamento de Medicina Veterinária, Centro de Ciências Rurais, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil. E-mail: flores@ccr.ufsm.br This paper reports the antibody response and fetal protection in pregnant cows conferred by an experimental vaccine containing two attenuated strains of bovine viral diarrhea virus (BVDV-1 and BVDV-2). Cows (n=19) were vaccinated twice, with a 34-days-interval, with the experimental vaccine and together with non-vaccinated controls (n=18), were mated and challenged between days 60 and 90 of gestation by intranasal inoculation of four heterologous BVDV-1 and BVDV-2 isolates. The antibody response was evaluated by serum-neutralization tests performed at different intervals after vaccination (days 34, 78 and 138 post-vaccination [pv]). Fetal protection was monitored by ultrassonographic and clinical examination of the dams and fetuses during the rest of gestation; and through virological and serological examination of pre-colostral blood obtained from aborted and/or recently born fetuses/calves. At the day of challenge (day 138 pv), all vaccinated cows had neutralizing antibodies in high titers against BVDV-1 (1,280- ³10,240), and with one exception (titer 20), presented moderate to high titers to BVDV-2 (80-1,280). At the end of the monitoring, only three out of 18 control cows (16.6%) delivered healthy, virus-free calves. Fifteen non-vaccinated cows (83.3%) presented signs of fetal infection and/or had reproductive losses. Seven of these cows (38.8%) delivered virus-positive calves; five were healthy and survived (27.7%); two were premature or weak and lasted three and 15 days, respectively. The other eight cows (44.4%) aborted between day 30 post-challenge and the parturition; or delivered premature or stillbirth calves. In contrast, 17 out of 19 (89.4%) vaccinated cows delivery virus-free, healthy calves. One vaccinated cow aborted around day 130 post-challenge, yet this fetus could not be examined for the presence of virus. Another cow delivered a virus-positive calf (5.2%). In summary, the experimental vaccine induced adequate antibody titers in most animals and the immunological response induced by vaccination was able to prevent fetal infection and reproductive losses upon challenge with a pool of heterologous BVDV isolates. Hence, this experimental vaccine may be an attractive alternative for the prevention of reproductive losses associated with BVDV infection.