A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge

The authors previously reported the construction of a glycoprotein E-deleted (gE-) mutant of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE-, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE-. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas non-vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE- could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE- was shown to be suitable for use as a BHV-1 differential vaccine viru

Vírus respiratório sincicial bovino: detecção por imunoistoquímica em tecidos de camundongos e bovinos usando AcM contra o vírus respiratório sincicial humano

An immunoistochemical (IHC) test was developed to detect bovine respiratory syncytial virus (BRSV) in cell cultures and tissues of experimentally infected mice and calves, using a commercial monoclonal antibody (Mab) against human respiratory syncytial virus (HRSV), as a less expensive alternative, instead of producing specific monoclonal antibodies to BRSV. Clinical samples from calves suffering respiratory disease were also submitted to this test. IHC detected BRSV antigens in mouse tracheas (3, 5 and 7 days post-infection) and lungs (5 and 7 days post-infection), and in one of three lungs from experimentally infected calves. Lungs samples from two naturally infected calves were tested and resulted positive for BRSV by the IHC test. These results suggest that this test may be used in the future for diagnosis as well as a useful tool to assess the distribution of BRSV infections in Brazilian herds.Desenvolveu-se um teste de imunohistoquímica (IHQ) para detecção do vírus respiratório sincicial bovino (BRSV) multiplicado em cultivo celular e em tecidos de camundongos e bezerros infectados experimentalmente, utilizando um anticorpo monoclonal comercial contra o vírus respiratório sincicial humano (HRSV), como uma alternativa para eliminar os custos de produção de anticorpos monoclonais específicos para o BRSV. Amostras clínicas de bezerros com sintomatologia respiratória foram analisadas. A técnica mostrou-se eficiente na detecção de antígenos do BRSV em traquéias (3, 5 e 7 dias pós-infecção) e pulmões (5 e 7 dias pós-infecção) dos camundongos infectados e em uma das três amostras de pulmões dos bezerros infectados experimentalmente. Amostras de pulmões de dois animais com infecção natural foram positivas para BRSV. Conclui-se que o teste de IHQ pode ser usado no diagnóstico das infecções por BRSV e na avaliação da distribuição dessas infecções nos rebanhos bovinos brasileiros.97398

Detection Of An Untyped Strain Of Bovine Respiratory Syncytial Virus In A Dairy Herd

Bovine respiratory syncytial virus (BRSV) causes important lower respiratory tract illness in calves. According to F and G proteins genetic sequences, three BRSV subgroups have been reported and characterized in several countries, showing differences in its distribution. In Brazil, the virus is widely disseminated throughout the herds and the few characterized isolates revealed the solely occurrence of the subgroup B. This study describes the detection and characterization of an untyped BRSV strain from a twenty-days-old calf from a herd without clinical respiratory disease. Nasal swabs were analyzed by RT-nested PCR for the F and G proteins genes. One sample has amplified the F protein gene. Sequencing and subsequent phylogenetic reconstruction were accomplished, revealing that the strain could not be grouped with any other BRSV subgroups reported. This result may suggest that the BRSV is in constantly evolution, even in Brazil, where the vaccination is not a common practice. More detailed studies about BRSV characterization are necessary to know the virus subgroups distribution among the Brazilian herds to recommend appropriated immunoprophylaxis.35525392550Affonso, I.B., Gatti, S.P., Alexandrino, B., Oliveira, M.C., Medeiros, A.S.R., Buzinaro, M.G., Samara, S.I., Detection of antibodies against bovine respiratory syncytial virus (BRSV) in dairy cattle with different prevalences of bovine herpesvirus type 1 (BHV-1) in São Paulo State, Brazil (2011) Semina: Ciências Agrárias, 32 (1), pp. 295-300. , LondrinaAlmeida, R.S., Domingues, H.G., Spilki, F.R., Larsen, L.E., Hagglund, S., Belák, S., Arns, C.W., Circulation of bovine respiratory syncytial virus in Brazil (2006) Veterinary Record, 158 (18), pp. 632-634. , LondonAlmeida, R.S., Spilki, F.R., Roehe, P.M., Arns, C.W., Detection of Brazilian bovine respiratory syncytial virus strain by a reverse transcriptase-nestedpolymerase chain reaction in experimentally infected calves (2005) Veterinary Microbiology, 105 (2), pp. 131-135. , AmsterdamArns, C.W., Campalans, J., Costa, S.C.B., Domingues, H.G., D'Arce, R.C.F., Almeida, R.S., Characterization of bovine respiratory syncytial virus isolated in Brazil (2003) Brazilian Journal of Medical and Biological Research, 36 (2), pp. 213-218. , Ribeirão PretoBaker, J.C., Frey, M., Bovine respiratory syncytial virus (1985) Veterinary Clinics of North America: Food Animal Practice, 1 (2), pp. 259-272. , PhiladelphiaBidokhti, M.R.M., Travén, M., Ohlson, A., Zarnegar, B., Baule, C., Belák, S., Alenius, S., Liu, L., Phylogenetic analysis of bovine respiratory syncytial viruses from recent outbreaks in feedlot and dairy cattle herds (2012) Archives of Virology, 157 (4), pp. 601-607. , New YorkBunt, A.A., Milne, R.G., Sayaya, T., Verbeek, M., Vetten, H.J., Walsh, J.A., Paramyxoviridae (2005) Virus Taxonomy, Eigth Report of the International Committee on Taxonomy of Viruses, pp. 655-671. , In: FAUQUET, C. M.MAYO, M. A.MANILOFF, J.DESSELBERGER, U.BALL, L. A. (Ed.). London: Elsevier: Academic PressCampalans, J., Arns, C.W., Serological evidence of bovine respiratory syncytial virus in Brazil (1997) Virus Reviews and Research, 2 (1-2), pp. 50-56. , Belo HorizonteDomingues, H.G., Spilki, F.R., Arns, C.W., Detecção molecular e análise filogenética de vírus respiratório sincicial bovino (BRSV) em swabs e tecido pulmonar de bovinos adultos (2011) Pesquisa Veterinária Brasileira, 31 (11), pp. 961-966. , Rio de JaneiroFurze, J.M., Roberts, S.R., Wertz, G.W., Taylor, G., Antigenically distinct G glycoproteins of BRSV strains share a high degree of genetic homogeneity (1997) Virology, 231 (1), pp. 48-58. , New YorkFurze, J., Wertz, G., Lerch, R., Taylor, G., Antigenic heterogeneity of the attachment protein of bovine respiratory syncytial virus (1994) Journal of General Virology, 75 (2), pp. 363-370. , LondonGonçalves, I.P.D., Simanke, A.T., Jost, H.C., Hötzel, I., Dal Soglio, A., Moojen, V., Detection of bovine respiratory syncytial virus in calves of Rio Grande do Sul, Brazil (1993) Ciência Rural, 23 (3), pp. 389-390. , Santa MariaHall, T.A., BioEdit: A user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT (1999) Nucleic Acids Symposium Series, 41, pp. 95-98. , OxfordLarsen, L.E., Bovine respiratory syncytial virus (BRSV): A review (2000) Acta Veterinaria Scandinavica, 41 (1), pp. 1-24. , CopenhagenLarsen, L.E., Tjornehoj, K., Viuff, B., Extensive sequence divergence among bovine respiratory syncytial viruses isolated during recurrent outbreaks in closed herds (2000) Journal of Clinical Microbiology, 38 (11), pp. 4222-4227. , WashingtonNettleton, P.F., Gilray, J.A., Caldow, G., Gidlow, J.R., Durkovic, B., Vilcek, S., Recent isolates of Bovine respiratory syncytial virus from Britain are more closely related to isolates from USA than to earlier British and current mainland European isolates (2003) Journal of Veterinary Medicine Series B-Infectious Diseases and Veterinary Public Health, 50 (4), pp. 196-199. , BerlinProzzi, D., Walravens, K., Langedijk, J.P., Daus, F., Kramps, J.A., Letesson, J.J., Antigenic and molecular analyses of the variability of bovine respiratory syncytial virus G glycoprotein (1997) Journal of General Virology, 78 (2), pp. 359-366. , LondonSchrijver, R.S., Daus, F., Kramps, J.A., Langedijk, J.P.M., Buijs, R., Middel, W.G.J., Taylor, G., Van Oirschot, J.T., Subgrouping of bovine respiratory syncytial virus strains detected in lung tissue (1996) Veterinary Microbiology, 53 (3-4), pp. 253-260. , AmsterdamSchrijver, R.S., Langedijk, J.P.M., Poel, V.D.M.W.H., Middel, W.G.J., Kramps, J.A., Van Oirschot, J.T., Antibody responses against the G and F proteins of bovine respiratory syncytial virus after experimental and natural infections (1996) Clinical and Diagnostic Laboratory Immunology, 3 (5), pp. 500-506. , WashingtonSchrijver, R.S., Langedijk, J.P.M., Middel, W.G.J., Kramps, J.A., Rijsewijk, F.A.M., Van Oirschot, J.T., A bovine respiratory syncytial virus strain with mutations in subgroup-specific antigenic domains of the G protein induces partial heterologous protection in cattle (1998) Veterinary Microbiology, 63 (2-4), pp. 159-175. , AmsterdamSpilki, F.R., Almeida, R.S., Domingues, H.G., D'Arce, R.C.F., Ferreira, H.L., Campalans, J., Costa, S.C.B., Arns, C.W., Phylogenetic relationships of Brazilian bovine respiratory syncyctial virus isolates and molecular homology modeling of attachment glycoprotein (2006) Virus Research, 116 (1-2), pp. 161-168. , AmsterdamSpilki, F.R., Arns, C.W., Vírus respiratório sincicial bovino (2008) Acta Scientiae Veterinariae, 36 (3), pp. 197-214. , Porto AlegreStine, L.C., Hoppe, D.K., Clayton, L.K., Sequence conservation in attachment glycoproteins and antigenic diversity among bovine respiratory syncytial virus isolates (1997) Veterinary Microbiology, 54 (3-4), pp. 201-221. , AmsterdamTamura, K., Dudley, J., Nei, M., Kumar, S., MEGA 4: Molecular evolutionary genetics analysis (MEGA) software version 4.0 (2007) Molecular Biology and Evolution, 24 (8), pp. 1596-1599. , ChicagoTaylor, G., Stott, E.J., Furze, J., Ford, J., Sopp, P., Protective epitopes on the fusion protein of respiratory syncytial virus recognized by murine and bovine monoclonal antibodies (1992) Journal of General Virology, 73 (9), pp. 2217-2223. , LondonTaylor, G., Thomas, L.H., Furze, J.M., Cook, R.S., Wyld, S.G., Lerch, R., Hardy, R., Wertz, G.W., Recombinant vaccinia viruses expressing the F, G or N, but not the M2, protein of bovine respiratory syncytial virus (BRSV) induce resistance to BRSV challenge in the calf and protect against the development of pneumonic lesions (1997) Journal of General Virology, 78 (12), pp. 3195-3206. , LondonThomas, L.H., Cook, R.S., Wyld, S.G., Furze, J.M., Taylor, G., Passive protection of gnotobiotic calves using monoclonal antibodies directed at different epitopes on the fusion protein of bovine respiratory syncytial virus (1998) Journal of Infectious Diseases, 177 (4), pp. 874-880. , ChicagoThompson, J.D., Higgins, D.G., Gibson, T.J., Clustal W: Improving the sensitivity of progressive multiple sequence alignment through sequence weighting, positions-specific gag penalties and weight matrix choice (1994) Nucleic Acids Research, 22 (22), pp. 4673-4680. , OxfordValarcher, J.F., Schelcher, F., Bourhy, H., Evolution of bovine respiratory syncytial virus (2000) Journal of Virology, 74 (22), pp. 10714-10728. , WashingtonValarcher, J.F., Taylor, G., Bovine respiratory syncytial virus infection (2007) Veterinary Research, 38 (2), pp. 153-180. , Les UlisPoel, V.D.W., Brand, A., Kramps, J.A., Van Oirschot, J.T., Respiratory syncytial virus infections in human beings and in cattle (1994) Journal of Infectious Diseases, 29 (2), pp. 215-228. , ChicagoVilcek, S., Elvander, M., Ballagi-Pordány, A., Belák, S., Development of nested PCR assays for detection of bovine respiratory syncytial virus in clinical samples (1994) Journal of Clinical Microbiology, 32 (9), pp. 2225-2231. , WashingtonWoelk, C.H., Holmes, E.C., Variable immune-driven natural selection in the attachment (G) glycoprotein of respiratory syncytial virus (RSV) (2001) Journal of Molecular Evolution, 52 (2), pp. 182-192. , ChicagoYaegashi, G., Seimiya, Y.M., Seki, Y., Tsunemitsu, H., Genetic and antigenic analyses of bovine respiratory syncytial virus detected in Japan (2005) Journal of Veterinary Medical Science, 67 (2), pp. 145-150. , Toky

Field Evaluation Of Safety During Gestation And Horizontal Spread Of A Recombinant Differential Bovine Herpesvirus 1 (bohv-1) Vaccine

Bovine herpesvirus type 1 (BoHV-1) is recognized as a major cause of respiratory, reproductive disease and abortion in cattle. Vaccination is widely applied to minimize losses induced by BoHV-1 infections; however, vaccination of dams during pregnancy with modified live virus (MLV) vaccines has been occasionally associated to abortions. We have previously reported the development of a BoHV-1 recombinant virus, constructed with basis on a Brazilian BoHV-1 (Franco et al. 2002a) from which the gene coding for glycoprotein E (gE) was deleted (gE-) by genetic manipulation. Such recombinant has been previously evaluated in its potential as a differential vaccine (gE-vaccine) that allows differentiation between vaccinated and infected animals. Here, in the first part of the present study, the safety of the gE-vaccine during pregnancy was evaluated by the intramuscular inoculation of 107.4 tissue culture 50% infective doses (TCID50) of the virus into 22 pregnant dams (14 BoHV-1 seronegative; 8 seropositive), at different stages of gestation. Other 15 pregnant dams were kept as non-vaccinated controls. No abortions, stillbirths or fetal abnormalities were seen after vaccination. Seroconversion was observed in both groups of previously seronegative vaccinated animals. In the second part of the study, the potential of the gE-vaccine virus to spread among beef cattle under field conditions was examined. Four heifers were inoculated intranasally with a larger amount (107.6TCID50) of the gE-vaccine (to increase chances of transmission) and mixed with other sixteen animals at the same age and body condition, in the same grazing area, at a population density equal to the average cattle farming density within the region (one cattle head per 10,000 m2), for 180 days. All animals were monitored daily for clinical signs. Serum samples were collected on days 0, 30, 60 and 180 post-vaccination. Seroconversion was observed only in vaccinated heifers. These results indicate that, under the conditions of the present study, the gE-vaccine virus did not cause any noticeable harmful effect on pregnant dams and on its offspring and did not spread horizontally among cattle.2515458Belknap, E.B., Walters, L.M., Kelling, C., Ayers, V.K., Norris, J., McMillend, J., Hayhowe, C., Collins, J.K., Immunogenicity and protective efficacy of a gE, gG and US2 gene-deleted bovine herpesvirus-1 (BHV-1) vaccine (1999) Vaccine, 17, pp. 2297-2305Bouma, A., De Jong, M.C.M., Kimman, T.G., Transmission of pseudorabies virus within pig populations is independent of the size of the population (1995) Prev. Vet. Med., 23, pp. 163-172Casal, J., Planasdemunt, L., Varo, J.A., Martín, M., The use of different vaccination schedules for sows to protect piglets against Aujeszky's disease (2004) Vet. Med. B, 51, pp. 8-11D'Arce, R.C.F., Almeida, R.S., Silva, T.C., Franco, A.C., Spilki, F., Roehe, P.M., Arns, C.W., Restriction endonuclease and monoclonal antibody characterization of Brazilian isolates of bovine herpesviruses types 1 and 5 (2002) Vet. Microbiol., 88, pp. 315-324Ellis, J.A., Hassard, L.E., Cortese, V.S., Morley, P.S., Effects of perinatal vaccination on humoral and cellular immune responses in dams and young calves (1996) J. Am. Vet. Med. Assoc., 208, pp. 393-400Flores, E.F., Donis, R.O., Isolation of a mutant MDBK cell line resistant to bovine viral diarrhea virus infection due to a block in viral entry (1995) Virology, 208, pp. 565-575Flores, E.F., Osorio, F.A., Zanella, E.L., Kit, S., Kit, M., Efficacy of a deletion mutant bovine herpesvirus-1 (BHV-1) vaccine that allows serologic differentiation of vaccinated from naturally infected animals (1993) J. Vet. Diagn. Invest., 5, pp. 534-540Franco, A.C., Rijsewijk, F.A.M., Flores, E.F., Weiblen, R., Roehe, P.M., Construction and characterization of a glycoprotein E deletion of bovine herpesvirus type 1.2 strain isolated in Brazil (2002) Braz. J. Microbiol., 33, pp. 274-278Franco, A.C., Spilki, F.R., Esteves, P.A., Lima, M., Weiblen, R., Flores, E.F., Rijsewijk, F.A.M., Roehe, P.M., A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge (2002) Pesq. Vet. Bras., 22, pp. 135-140Hage, J.J., Schukken, Y.H., Barkema, H.W., Benedictus, G., Rijsewijk, F.A.M., Wentink, G.H., Population dynamics of bovine herpesvirus infection a dairy herd (1996) Vet. Microbiol., 53, pp. 169-180Guy, J.S., Potgieter, L.N., Bovine herpesvirus-1 infection of cattle: Kinetics of antibody formation after intranasal exposure and abortion induced by the virus (1985) Am. J. Vet. Res., 46, pp. 893-898Kaashoek, M., (1995) Marker Vaccines Against Bovine Herpesvirus 1 Infections, 155p. , Ph.D. Thesis, Utrecht University, NetherlandsKleiboeker, S.B., Lee, S.M., Jones, C.A., Estes, D.M., Evaluation of shedding of bovine herpesvirus 1, bovine viral diarrhea virus 1, and bovine viral diarrhea virus 2 after vaccination of calves with a multivalent modified-live virus vaccine (2003) J. Am. Vet. Med Assoc., 222, pp. 1399-1403Lomba, F., Vascoboinic, E., Zygraich, N., Immunization of pregnant dams with a temperature-sensitive mutant of the IBR Virus (1976) 6th Int. Congr. Diseases of Cattle, pp. 395-399. , ParisMars, M.H., De Jong, M.C.M., Van Oirschot, J.T., A gE-negative BHV-1 vaccine virus strain cannot perpetuate in cattle populations (2000) Vaccine, 18, pp. 2120-2124McFelly, R.A., Merrit, A.M., Stearly, E.L., Abortion in a dairy herd vaccinated for infectious bovine rhinotracheitis (1964) Vet. Path., 1, pp. 7-17Miller, J.M., Whetstone, C.A., Van Der Maaten, M.J., Abortfacient property of bovine herpesvirus type 1 isolates that represent three subtypes determined by restriction endonuclease analysis of viral DNA (1991) Am. J. Vet. Res., 52, pp. 458-461Miller, J.M., Whetstone, C.A., Bello, L.J., Lawrence, W.C., Whitbeck, J.C., Abortions in heifers inoculated with a thymidine kinase-negative recombinant of bovine herpesvirus 1 (1995) Am. J. Vet. Res., 56, pp. 870-874Mitchell, D., An outbreak of abortion in a dairy herd following inoculation with an intramuscular infectious bovine rhinotracheitis virus (1964) Can. Vet. J., 26, pp. 8-14Odde, K.G., Survival of the neonatal calf. Factors influencing colostral and calf serum immunoglobulin levels (1988) Vet. Clin. North Am. Food Anim. Pract., 4, pp. 501-508Pastoret, P.P., Babiuk, L.A., Misra, V., Griebel, P., Reactivation of temperature sensitive and non-temperature-sensitive infectious bovine rhinotracheitis vaccine virus with dexamethasone (1980) Infect. Immun., 29, pp. 483-488Roehe, P.M., (1991) Studies on the Comparative Virology of Pestiviruses, 361p. , Ph.D. thesis. University of Surrey, Guildford, UKSiebert, S., Auer, S., Heinem, E., Kretzdom, D., Strube, W., Marker vaccines - Opportunities for IBR control. Part I: BHV-1 infections - The problem (1995) Tierärztl. Umschau, 50, pp. 530-533Siebert, S., Auer, S., Heinem, E., Kretzdom, D., Strube, W., Marker vaccines - Opportunities for IBR control. Part II: Safety and efficacy of the gE-deleted Bayovac IBR marker vaccines (1995) Tierärztl. Umschau, 50, pp. 582-584Strube, W., Abar, B., Bergle, R.D., Safety aspects in the development of an infectious bovine rhinotracheitis marker vaccine. Non-target effects of live vaccines (1995) Dev. Biol. Stand., 84, pp. 75-81Turin, L., Russo, S., Poli, G., BHV-1: New molecular approaches to control a common and widespread infection (1999) Mol. Med., 5, pp. 261-284Van Drunen Littel-van Den Hurk, S., Parker, M.D., Massie, B., Van Den Hurk, J.V., Harland, R., Babiuk, L.A., Zamb, T.J., Protection of cattle from BHV-1 infection by immunization with recombinant glycoprotein gIV (1993) Vaccine, 11, pp. 25-35Van Engelenburg, F.A.C., Kaashoek, M.J., Van Oirschot, J.T., Rijsewijk, F.A.M., A glycoprotein E deletion mutant of bovine herpesvirus 1 infects the same limited number of tissues in calves as wild-type virus, but for a shorter period (1995) J. Gen. Virol., 76, pp. 2387-2392Wentink, G.H., Van Oirschot, J.T., Verhoeff, J., Risk of infection with bovine herpes virus 1 (BHV-1): A review (1993) Vet. Quarterly, 15, pp. 30-33Whetstone, C.A., Wheeler, J.G., Reed, D.E., Investigation of possible vaccine-induced epizootics of infectious bovine rhinotracheitis, using restriction endonuclease analysis of viral DNA (1986) Am. J. Vet. Res., 47, pp. 1789-1795Zuckermann, F.A., Husmann, R.J., Schwartz, R., Brandt, J., Mateu De Antonio, E., Martin, S., Interleukin-12 enhances the virus-specific interferon gamma response of pigs to an inactivated pseudorabies virus vaccine (1998) Vet. Immunol. Immunopath., 63, pp. 57-6

Comparative Evaluation Of Conventional Rt-pcr And Real-time Rt-pcr (rrt-pcr) For Detection Of Avian Metapneumovirus Subtype A [comparação Entre As Técnicas De Rt-pcr Convencional E Rt-pcr Em Tempo Real Para A Detecção Do Metapneumovírus Aviários Subtipo A]

Avian metapneumovirus (AMPV) belongs to Metapneumovirus genus of Paramyxoviridae family. Virus isolation, serology, and detection of genomic RNA are used as diagnostic methods for AMPV. The aim of the present study was to compare the detection of six subgroup A AMPV isolates (AMPV/A) viral RNA by using different conventional and real time RT-PCR methods. Two new RT-PCR tests and two real time RT-PCR tests, both detecting fusion (F) gene and nucleocapsid (N) gene were compared with an established test for the attachment (G) gene. All the RT-PCR tested assays were able to detect the AMPV/A. The lower detection limits were observed using the N-, F- based RRT-PCR and F-based conventional RT-PCR (10 0.3 to 10 1 TCID 50 mL -1). The present study suggests that the conventional F-based RT-PCR presented similar detection limit when compared to N- and F-based RRT-PCR and they can be successfully used for AMPV/A detection.39514451451Arns, C.W., Hafez, M.H., (1992) Swollen Head Syndrome in Poultry Flocks in Brazil, pp. 81-84. , In: WESTERN POULTRY DISEASE CONFERENCE, 41., 1992, Sacramento, USA. Proceedings... 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Prevalence of newcastle disease virus in broiler chickens (Gallus gallus) in Brazil

This study was carried out during 2002/2003, aiming to determine the prevalence of virulent Newcastle disease virus strains (NDV) in Brazilian commercial poultry farms. Clinical samples were obtained from the Southeastern, Southern and Central-Western regions, which comprise the main area of the Brazilian poultry production. Serum samples and tracheal and cloacal swabs of 23,745 broiler chickens from 1,583 flocks, including both vaccinated chickens and those with no vaccination information, were tested for NDV using a diagnostic ELISA kit. The seropositivity was 39.1%, and the isolation percentage by flock varied from 1.0 to 7.6%, and by region from 6.5 to 58.4%. Higher isolation rates (74.3-83.3%) were obtained after three passages in embryonated chicken eggs. All isolates preliminarily identified as NDV were characterized as nonpathogenic strains, as their Intracerebral Pathogenicity Index (ICPI) was below 0.7. Based on results of this study, Brazil can claim a virulent NDV-free status for commercial flocks.349357Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

A survey for maintenance of virulent newcastle disease virus-free area in poultry production in Brazil

In 2003, Brazil was recognized as a pathogenic Newcastle Disease Virus (NDV) strain-free country for commercial poultry. This research was conducted in Brazil between December 2003 and March 2005 to verify the maintenance of this virulent NDV-free status. Serum samples from 5,455 flocks for commercial poultry farms were collected, comprising 81,825 broiler chickens. The farms were located in nine states of the country, grouped in three geographic regions. Serological evidence of NDV infection was detected in 28.8% of the surveyed farms. However, all fifteen viruses isolated and identified as Newcastle Disease Virus (NDV) were characterized as nonpathogenic strains, based on the Intracerebral Pathogenicity Index. These results showed that Brazil preserves the virulent NDV-free status for commercial flocks.368375Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Antigenic and molecular characterization of eight samples of Aujeszky's disease virus isolated in the state of Rio Grande do Sul, Brazil, in 2003

Pseudorabies or Aujeszky's disease (AD), caused by pseudorabies virus (PRV) is a major concern in swine production. In the state of Rio Grande do Sul, Brazil, AD was only detected in 1954, in cattle. In 2003 two outbreaks of encephalitis occurred on the northern region of the state, close to the border with the state of Santa Catarina. Pseudorabies virus (PRV) was isolated from distinct farms within the region and subjected to antigenic and genomic analyses. These isolates were compared with prototype strains NIA-3 and NP. Antigenic characterization with a panel of monoclonal antibodies (Mabs) directed to viral glycoproteins (gB, gC, gD and gE-,) was performed by an imunoperoxidase monolayer assay (IPMA) on infected cell monolayers. Genomic characterization was carried out by restriction enzyme analysis (REA) of the whole DNA viral genome with Bam HI. The antigenic profile of the eight isolates from Rio Grande do Sul as well as strains NIA-3 and NP were similar. REA analysis revealed that all isolates from Rio Grande do Sul displayed a genomic type II arrangement, a genotype often found in other outbreaks of AD previously reported in other Brazilian states. The results obtained suggest that the eight isolates examined here were similar