Tracheal post-vaccinal reaction to different strains of Newcastle disease vírus / Reação traqueal pós-vacinal à diferentes cepas do vírus da doença de Newcastle

The aim of the present study was to evaluate the post-vaccinal reaction to two lentogenic vaccine strains of Newcatle disease virus (NDV) and a recombinant turkey herpesvirus (rHVT) vaccine expressing the fusion glycoprotein of NDV in broiler chickens through histomorphometric and histopathologic analyses of the trachea. The experiment involved 245 chicks housed in randomized blocks with three different enclosures under controlled conditions of temperature, light and ventilation. Each enclosure represented a vaccine strain and was divided into groups according to the administration route. Each block also had its own control group composed of unvaccinated birds. The vaccine strains PHY.LMV.42 (PL42) and La Sota (LS) were selected according to the Intracerebral Pathogenicity Index (ICPI) and the rHVT-NDV Serotype 3 strain (ST3) was selected for representing non-NDV infection. At two, four, seven, 14 and 21 days post vaccination, fragments from the middle third of the trachea were collected and submitted to routine histological processing. For the histomorphometric analysis, the slides were photographed, and the thickness of the tracheal mucosa was measured. Statistical analysis involved two-way ANOVA and Tukey's post-hoc test with a 5% significance level. For the histopathological evaluation, lesions were described as to the degree of intensity and distribution. At four and 14 days post vaccination with the LS strain administered by the ocular route, the means of thickening of the tracheal mucosa (20.85±7.31µm and 26.97±5.50µm, respectively) were significantly higher (p<0.05) than for all other strains, which was related to the severe histopathological lesions found in this group, characterized by hyperemia, hyperplasia of the mucous glands, moderate deciliation and multifocal lymphohistiocytic inflammatory infiltrate. At 21 days, broiler chickens vaccinated with the ST3 strain showed more discrete lesions and less thickening of the tracheal mucosa (23.23±7.62µm; p<0.05) in comparison with other studied strains. The lesions found in this group were only hemorrhage, deciliation and mild focal lymphocytic inflammatory infiltrate. The results of the histomorphometry and histopathology of the trachea indicated that vaccination with rHVT-NDV Serotype 3 strain induced lower degree post-vaccine tracheal lesions compared to other vaccine strains analyzed in this study.

Objetivou-se avaliar a reação pós-vacinal de duas estirpes lentogênicas do vírus da doença de Newcastle (VDN) e uma vacina recombinante de herpesvirus de perus (rHVT) que expressa a glicoproteína de fusão de VDN em frangos de corte por meio da histomorfometria e histopatologia da traqueia. Foram utilizados 245 pintos alojados em blocos ao acaso, sendo três galpões distintos em condições controladas de temperatura, luz e ventilação. Cada galpão representou uma cepa vacinal, onde foram divididos por grupos de acordo com a via de administração. Todos os blocos possuíam um grupo controle composto por aves não vacinadas. As cepas vacinais PHY.LMV.42 (PL42) e La Sota (LS) utilizadas foram selecionadas de acordo com o Índice de Patogenicidade Intracerebral (IPIC) e a cepa Sorotipo 3 (ST3), da vacina rHVT-VDN foi selecionada por não representar infecção do VDN. Aos dois, quarto, sete, 14 e 21 dias pós-vacinação, fragmentos do terço médio da traqueia foram coletados e posteriormente processados conforme rotina histológica. Para análise histomorfométrica da mucosa traqueal, as lâminas foram fotografadas e realizadas as mensurações da espessura da mucosa traqueal sendo aplicado teste de análise de variância a dois critérios (ANOVA) e utilizando o post-hoc de Tukey com nível de significância de 5%. Para a avaliação histopatológica foram observadas a presença de lesões microscópicas e estas foram descritas quanto ao grau de intensidade e distribuição. Aos quatro e quatorze dias pós-vacinação com a cepa LS administrada por via ocular, as médias do espessamento da mucosa traqueal (20,85±7,31µm e 26,97±5,50µm, respectivamente) foram significativamente maiores (p<0,05) quando comparada a todas as demais cepas utilizadas, isto se deve às severas lesões histopatológicas encontrados neste grupo, caracterizadas por hiperemia, hiperplasia das glândulas mucosas, deciliação moderada e infiltrado inflamatório linfohistiocitário multifocal moderado. Já aos 21 dias as aves vacinadas com a cepa ST3 apresentaram lesões mais discretas e menor espessamento da mucosa da traqueia (23,23±7,62µm; p<0,05) em comparação às demais cepas estudadas. As lesões encontradas neste grupo foram apenas hemorragia, deciliação e infiltrado inflamatório linfocitário focal discreto. Os resultados da histomorfometria e da histopatologia da traqueia indicou que a vacinação com a rHVT-NDV, cepa Sorotipo 3 induziu menor grau de lesões pós-vacinais na traqueia comparada a outras cepas vacinais analisadas nesse estudo.

Comparative evaluation of the protective efficacy of different vaccination programs against a virulent field strain of the Newcastle disease virus in broilers

Despite the intensive vaccination programs used for controlling Newcastle disease (ND) in the Iranian poultry industry, outbreaks of ND have been reported in poultry farms. This study was conducted to evaluate the effectiveness of vaccines for the protection against ND infection and virus-shedding period of velogenic Newcastle disease virus (vNDV) field strain after different immunization schemes. Eight groups of commercial broiler chickens were used. Six groups were vaccinated with different vaccination programs using commercial live and inactivated ND vaccines. All groups, except for group 8, were challenged with a virulent field isolate (104EID50/bird) at 28 days of age. Clinical signs, mortality rate and gross lesions were investigated. Antibody titers were assayed by hemagglutination inhibition test and fecal virus shedding was determined for 14 days post challenge (dpc) with 3-day intervals by the RT-PCR method. All unvaccinated-challenged control birds died. Vaccination with these ND vaccines protected chickens from clinical disease. The mortality rate in the vaccinated groups was significantly lower than in the positive control group. However, vaccinated chickens shed the challenge virus in fecal samples. Although the different vaccination regimens displayed close degrees of protection against the disease, the best protection was observed in broilers primed with the live B1 vaccine via eye drop simultaneously with inactivated vaccine at 8 days of age and boosted with B1 or LaSota via drinking water on day 18. In conclusion, the currently used vaccines with different vaccination schemes can protect chickens against the disease in areas where ND is endemic, while the spread of the field virus to other flocks cannot be prevented.

Comparative evaluation of the protective efficacy of different vaccination programs against a virulent field strain of the Newcastle disease virus in broilers

Despite the intensive vaccination programs used for controlling Newcastle disease (ND) in the Iranian poultry industry, outbreaks of ND have been reported in poultry farms. This study was conducted to evaluate the effectiveness of vaccines for the protection against ND infection and virus-shedding period of velogenic Newcastle disease virus (vNDV) field strain after different immunization schemes. Eight groups of commercial broiler chickens were used. Six groups were vaccinated with different vaccination programs using commercial live and inactivated ND vaccines. All groups, except for group 8, were challenged with a virulent field isolate (104EID50/bird) at 28 days of age. Clinical signs, mortality rate and gross lesions were investigated. Antibody titers were assayed by hemagglutination inhibition test and fecal virus shedding was determined for 14 days post challenge (dpc) with 3-day intervals by the RT-PCR method. All unvaccinated-challenged control birds died. Vaccination with these ND vaccines protected chickens from clinical disease. The mortality rate in the vaccinated groups was significantly lower than in the positive control group. However, vaccinated chickens shed the challenge virus in fecal samples. Although the different vaccination regimens displayed close degrees of protection against the disease, the best protection was observed in broilers primed with the live B1 vaccine via eye drop simultaneously with inactivated vaccine at 8 days of age and boosted with B1 or LaSota via drinking water on day 18. In conclusion, the currently used vaccines with different vaccination schemes can protect chickens against the disease in areas where ND is endemic, while the spread of the field virus to other flocks cannot be prevented.(AU)

Vigilância epidemiológica dos vírus da influenza aviária, da doença de Newcastle e da laringotraqueíte infecciosa das galinhas em propriedades avícolas

A sanidade avícola é necessária para garantir a posição de destaque mundial da avicultura brasileira. O objetivo deste trabalho foi realizar a vigilância epidemiológica do vírus da IA (VIA) e do vírus da DNC (VDNC) em 2017 e 2018, além de avaliar a circulação de estirpes do vírus de laringotraqueíte infecciosa das galinhas (VLTI) nas granjas de postura comercial em duas regiões quarentemadas (Bastos e Guatapará) entre 2010 e 2018. Diferentes programas vacinais contra a LTI foram implementados na região, com a substituição de vacinas vivas atenuadas por recombinantes em 2012 (Bastos) e 2013 (Guatapará). Para a vigilância de VIA e VDNC foram coletados pools de suabes (traqueais e cloacais, n=220) de aves de subsistências localizadas no entorno de propriedades avícolas de reprodutoras. Essas amostras foram testadas pela reação de transcrição reversa-PCR em tempo real (RRT-PCR). O estudo longitudinal de VLTI coletou amostras de pools de suabes orofaríngeos de aves localizadas em Bastos (n=364) e Guatapará (n=214) para a detecção de VLTI por PCR. O sequenciamento de DNA dos genes ICP4, TK e genomas completos das amostras positivas foram realizados usando sequenciamento Sanger e sequenciamento de última geração (NGS). As bibliotecas de DNA foram preparadas com o kit Nextera DNA Flex Library Prep e sequenciadas com o sequenciador MiSeq. Análise filogenética e as identidades genéticas foram inferidas com as sequências obtidas. Nosso estudo não detectou VIA e do VDNC em nenhuma das amostras no período avaliado. O VLTI foi detectado em 11,85% e 12,6% das amostras testadas de Bastos em 2013 e 2018. A região de Guatapará apresentou a maior taxa de detecção (60,5%) em 2010. A taxa de detecção de amostras testadas da região de Guatapará variou de 12,2% e 21,7% após 2013. Análise filogenética do gene ICP4 agrupou as sequências das amostras de Bastos com vacinas de CEO e outras sequências de Bastos detectadas em anos anteriores, com 99% da identidade genética entre estas sequências. As análises filogenéticas dos genes ICP4, TK e do genoma completo agruparam as amostras de Guatapará separadamente das amostras vacinais. A sequência completa do genoma de uma amostra obtida de aves sintomáticas sem vacinação na região de Guatapará em 2010 (IB8098) teve 152.985 nucleotídeos, com 4755 leituras e 98,2% de cobertura. A análise filogenética agrupou a amostra IB8098 com outras estirpes virulentas, como da Rússia (MF405079). As identidades genéticas apresentaram 99,9%, quando comparadas à estirpe russa e 99,6% em relação às vacinais (CEO e TCO). Nosso estudo mostrou o VLTI ainda está presente nas regiões de Bastos e Guatapará, apesar das medidas de controle e vacinação vigentes. Os programas de vacinação nas regiões quarentenadas diminuíram a circulação do vírus com um leve aumento da detecção do VLTI com a utilização apenas das vacinas recombinantes. Esse é o primeiro relato da obtenção do genoma completo de VLTI no Brasil e sua caracterização genômica desde o início da circulação do vírus na região há pelo menos dez anos. O monitoramento contínuo da área é essencial para auxiliar as ações da defesa agropecuária, avaliar as medidas de vacinação implementadas contribuindo para a melhoria da sanidade avícola.

Poultry health is important to ensure the world's leading position in Brazilian poultry production. The present study performed the epidemiological surveillance of avian influenza virus (AIV) and Newcastle disease virus (NDV) in 2017 and 2018; the circulation of virulent avian infection laryngotracheitis virus (ILTV) strains was also evaluated in commercial layer farms from two quarantined regions (Bastos and Guatapara) between 2010 and 2018. Different vaccine programs against ILT were established in the area, and a replacement of live vaccines by recombinant vaccines was done in 2012 (Bastos) and 2013 (Guatapara). For the AIV and NDV surveillance, swab pool samples (trachea and cloacal, n=220) were collected from backyard birds located closed to breeder farms. Real-time reverse-transcription polymerase chain reaction (RRT-PCR) tested these samples. The longitudinal study collected oropharyngeal swab pool samples from commercial layer chickens located in Bastos (n=364) and Guatapara (n=214) for virus ILTV detection by PCR. DNA sequencing from the ICP4, TK genes and complete genomes was performed in positive samples using Sanger sequencing and next-generation sequencing (NGS). DNA libraries were prepared with the Nextera DNA Flex Library Prep kit, sequenced with the MiSeq sequencer for NGS. Phylogenetic analysis and genetic identities were inferred using the obtained sequences. AIV and NDV were not detected in any sample during the study. ILTV was detected in 11.85% and 12.6% of tested samples from Bastos in 2013 and 2018. Guatapara region had the highest detection rate (60.5%) in 2010. The detection rate from tested samples of the Guatapara region ranged from 12.2% and 21.7% after 2013. Phylogenetic analysis based on ICP4 gene grouped sequences from Bastos samples with CEO vaccines and other sequences detected previously in Bastos, with 99% of nucleotide identity among them. Phylogenetic analysis based on ICP4, TK, and complete genomes grouped sequences from Guatapara separately from vaccine strains. The complete genome sequence of a sample (IB8098), collected from layer chickens displaying clinical signs without vaccination in the Guatapara region in 2010, had 152,985 nucleotides, with 4,755 reads and 98,2% coverage. The phylogenetic analysis grouped the IB8098 sample with other virulent ILTV strains, such as from Russia (MF405079). Nucleotide identities were 99.9% compared to the Russian, and 99.6% to vaccine strains (CEO and TCO). Our study showed the ILTV is still present in the Bastos and Guatapara regions, despite the control and vaccination measures. The vaccination programs in the quarantine regions decreased the virus circulation, slightly increasing when only recombinant vaccines were applied. That is the first report of complete genome ILTV sequences in Brazil and its genomic characterization, after its circulation in the region for at least ten years. Continuous monitoring in poultry flocks is essential to help the poultry health measures, evaluate the vaccination programs placed in the area contributing to the Brazilian poultry health plans improvement.

Assessment of the pathogenicity of cell-culture-adapted Newcastle disease virus strain Komarov

Newcastle disease vaccines hitherto in vogue are produced from embryonated chicken eggs. Egg-adapted mesogenic vaccines possess several drawbacks such as paralysis and mortality in 2-week-old chicks and reduced egg production in the egg-laying flock. Owing to these possible drawbacks, we attempted to reduce the vaccine virulence for safe vaccination by adapting the virus in a chicken embryo fibroblast cell culture (CEFCC) system. Eighteen passages were carried out by CEFCC, and the pathogenicity was assessed on the basis of the mean death time, intracerebral pathogenicity index, and intravenous pathogenicity index, at equal passage intervals. Although the reduction in virulence demonstrated with increasing passage levels in CEFCC was encouraging, 20% of the 2-week-old birds showed paralytic symptoms with the virus vaccine from the 18th(final) passage. Thus, a tissue-culture-adapted vaccine would demand a few more passages by CEFCC in order to achieve a complete reduction in virulence for use as a safe and effective vaccine, especially among younger chicks. Moreover, it can be safely administered even to unprimed 8-week-old birds.(AU)

Newcastle disease virus vaccine strains: immunogenicity is not influenced by ICPI

Intracerebral pathogenicity index (ICPI) and mean death time (MDT) were determined using commercial live vaccines against Newcastle disease available in Brazil. The ICPI profiles obtained for B1 vaccine strains were nonvirulent and varied from 0 to 0.19, and their MDT was 104-116 hours. The LaSota strains had an ICPI varying between 0.02 and 0.37 and MDT from 92 to 116 hours. ICPI and MDT for the Clone 30 were 0.11 and 104 hours, respectively. For Ulster vaccines, ICPI and MDT were 0 and >150 hours; for VG-GA was 0.03 and 140 hours; and for C2, 0.04 and >144 hours. Eye drop vaccination and IM challenge, at the 1st week and the 4th week, respectively, resulted in highest protection for B1 (95-100%) and LaSota (90-100%) strains. The variability in vaccine ICPI did not interfere with immune response and all vaccines provided similar protection. All vaccines were considered non virulent and were classified as lentogenic according to the immunobiological product standards.

Newcastle disease virus vaccine strains: immunogenicity is not influenced by ICPI

Intracerebral pathogenicity index (ICPI) and mean death time (MDT) were determined using commercial live vaccines against Newcastle disease available in Brazil. The ICPI profiles obtained for B1 vaccine strains were nonvirulent and varied from 0 to 0.19, and their MDT was 104-116 hours. The LaSota strains had an ICPI varying between 0.02 and 0.37 and MDT from 92 to 116 hours. ICPI and MDT for the Clone 30 were 0.11 and 104 hours, respectively. For Ulster vaccines, ICPI and MDT were 0 and >150 hours; for VG-GA was 0.03 and 140 hours; and for C2, 0.04 and >144 hours. Eye drop vaccination and IM challenge, at the 1st week and the 4th week, respectively, resulted in highest protection for B1 (95-100%) and LaSota (90-100%) strains. The variability in vaccine ICPI did not interfere with immune response and all vaccines provided similar protection. All vaccines were considered non virulent and were classified as lentogenic according to the immunobiological product standards.

Avaliação de diferentes vias vacinais para vacinação contra o vírus da doença de Newcastle em aves de fundo de quintal / Assessment of different vaccination approaches against Newcastle disease virus in domestic backyard poultry

Foram avaliadas três vias de aplicação vacinal contra o vírus da doença de Newcastle em aves de criatório de fundo de quintal (AFQ) jovens e adultas. Um total de 135 AFQ foram distribuídas em tratamentos distintos de acordo com a via vacinal: via ocular (VO), água de bebida (VAB) e alimentar (VA). Cada tratamento foi representado por 40 aves (20 jovens e 20 adultas) e utilizou-se um grupo-controle de 15 aves não vacinadas. O programa de vacinação estabelecido constou de uma primovacinação e dois reforços vacinais, utilizando-se a cepa La Sota. Para aves jovens, os títulos obtidos pelas VO e VAB não diferiram aos 15, 45 e 140 dias, mas houve diferenças nos títulos das aves vacinadas pela VA. Nas aves adultas, a vacinação pela VO apresentou resultados mais elevados que as vacinações pelas VAB e VA na primeira resposta, aos 15 dias. Aos 45 dias, os títulos obtidos pela VAB foram mais baixos que os obtidos pela VO, e, aos 140 dias, não houve diferença entre as três vias avaliadas. Concluiu-se que as vacinações pelas VO e VAB constituem alternativas eficazes para vacinação de AFQ jovens e adultas.(AU)

Three ways of vaccination against Newcastle Disease Virus (NDV) were evaluated in young and adults domestic backyard poultry (DBP). A total of 135 DBP was submitted to three different administration routes of ND vaccine: eye-drop, drinking water, and feed. Each treatment consisted of 40 birds (20 young and 20 adult) and a control group of 15 unvaccinated birds. The treatment consisted of a first vaccination and two boosters, using La Sota strain. For young birds, the eye-drop and drinking water vaccinations presented no differences at 15, 45, and 140 days, differing from the titers obtained by birds treated by feed vaccination method. In the adult birds, the eye-drop administration presented higher titers than by drinking water and feed approaches in the first response to the vaccination at 15 days. At 45 days, the results obtained by the drinking water had lower titers than those from the eye-drop. The three vaccination methods presented no difference at 140 days. In conclusion, the vaccination by eye-drop and drinking water methods constituted an efficient alternative of vaccination for adult and young DBP against Newcastle virus.(AU)

Estudo de parâmetros clínicos e imunitários da vacinação contra a doença de Newcastle e sua importância epidemiológica em Agapornis (Agapornis roseicollis)

As avaliações dos parâmetros clínicos, imunitários e epidemiológicos da vacinação contra a doença de Newcastle (DN) em agapornis (Agapornis roseicollis) foram investigadas em dois experimentos. Amostras vacinais Ulster 2C, B1 e LaSota do vírus da doença de Newcastle (VDN) foram utilizadas para imunização das aves. No experimento 1, utilizaram-se 48 agapornis, distribuídos em quatro tratamentos de 12 animais cada, num total de três repetições, submetidos a diferentes esquemas imunoprofiláticos. A resposta imune foi avaliada pelo teste de HI. Não foram observados sinais clínicos de reação pós-vacinal em qualquer grupo experimental. Os resultados dos títulos de anticorpos (HI) mostraram que a estirpe vacinal LaSota conferiu maior grau de imunidade aos agapornis, quando comparada às estirpes Ulster 2C e B1. Estas aves foram posteriormente desafiadas frente a uma estirpe patogênica do VDN (EID50=108,15/0,1mL), aos 12 meses de idade. Em todos os grupos, procedeu-se a pesquisa do RNA viral a partir de suabes cloacais, através da técnica de RT-PCR. Os agapornis de todos os grupos não demonstraram qualquer sinal clínico sugestivo da DN, mostrando-se refratários à doença clínica frente a este vírus. Entretanto, ficou caracterizado o estado de portador de VDN nesta espécie decorridos até 21 dias da infecção experimental com este patógeno. No experimento 2, foram utilizadas aves SPF (?Specific-Pathogen-Free?) conviventes com agapornis inoculados com uma estirpe patogênica do VDN. Observou-se a transmissão do VDN dos agapornis para as aves SPF conviventes decorridos até 21 da infecção experimental com este patógeno, o que realça a importância do agapornis como fonte potencial de infecção do VDN para aves domésticas

The evaluations of clinical, immunological and epidemiological parameters of vaccination against Newcastle disease (ND) in lovebirds (Agapornis roseicollis) were investigated in 2 experiments. Ulster 2C, B1 and LaSota vaccines strains of the Newcastle disease virus (NDV) were used to immunization of birds. In experiment 1, 48 lovebirds were distributed into 4 different treatments, with 12 birds in each, with a total of 3 repetitions, submitted to different vaccination programs. The immunological responses were measured by HI test. Lovebirds from all groups did not show any clinical signs of post vaccinal reaction. The antibody titers (HI) results showed that the immune vaccine programs adopted were different in stimulating protective levels of humoral immune response. These birds were also challenge with a pathogenic NDV strain (EID50=108.15/0.1mL) at 12 months of age. After the challenge in all groups, cloacal swabs were collected for RT-PCT to find the pathogenic viruses. Lovebirds from all groups did not demonstrate clinical signs of ND, being refractory to the clinical disease with the NDV. However, a NDV carrier state was demonstrated in this specie until 21 days after experimental infection. In experiment 2, SPF chicks were housed with lovebirds previously inoculated with a pathogenic NDV strain. The pathogenic virus (NDV) was transmitted from lovebirds to SPF chicks until 21 days after challenge, showing the importance of the lovebirds as source of dissemination of NDV to domestic birds

Interference of infectious bursal disease virus on antibody production against Newcastle disease and infectious bronchitis virus

This work has the objective of verifying the interference of infectious bursal disease virus in the antibody production against Newcastle disease virus and infectious bronchitis virus. The experiment was carried out with 640 day-old-chicks from a 42 weeks old hen flock. The birds were separated into eight experimental groups (n=80/group) and were submitted to different combinations of vaccinations, with live vaccines, to Newcastle disease, avian infectious bronchitis, and infectious bursal disease with diverse combinations of days of vaccination. We verified that the utilization of polyvalent vaccinal programs have a different efficacy comparing to monovalent vaccinations when Newcastle disease, infectious bronchitis, and infectious bursal disease vaccinations are applied. This way, the use of vaccinations to infectious bursal disease in polyvalent vaccinal programs is desirable due to improvement of NDV response with the presence of IBV by the probable reduction of interference of IBV under NDV.

Interference of infectious bursal disease virus on antibody production against Newcastle disease and infectious bronchitis virus

This work has the objective of verifying the interference of infectious bursal disease virus in the antibody production against Newcastle disease virus and infectious bronchitis virus. The experiment was carried out with 640 day-old-chicks from a 42 weeks old hen flock. The birds were separated into eight experimental groups (n=80/group) and were submitted to different combinations of vaccinations, with live vaccines, to Newcastle disease, avian infectious bronchitis, and infectious bursal disease with diverse combinations of days of vaccination. We verified that the utilization of polyvalent vaccinal programs have a different efficacy comparing to monovalent vaccinations when Newcastle disease, infectious bronchitis, and infectious bursal disease vaccinations are applied. This way, the use of vaccinations to infectious bursal disease in polyvalent vaccinal programs is desirable due to improvement of NDV response with the presence of IBV by the probable reduction of interference of IBV under NDV.

Effect of associated vaccines on the interference between Newcastle disease virus and infectious bronchitis virus in broilers

The phenomenon of viral interference between live vaccines against Newcastle Disease and infectious bronchitis has been reported since the 50's and many researchers have reported its prejudicial effects on avian immunization. Therefore, this study evaluated the effect of associated vaccines on the interference between Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) in broilers. There were 400 broiler chicks divided into five groups. The groups were submitted to mono or polyvalent vaccinations against IBV and NDV, except for the non-vaccinated control group (CG). Sera were collected at 35 and 45 days of age and submitted to serologic tests to assess antibody levels. It was observed the occurrence of interference in the immune response against NDV by the use of associated vaccines to NDV and IBV; however, the group that was immunized with commercial combined vaccines (IBV+NDV) presented antibody titers to NDV similar to the group that was given only vaccine against NDV. We concluded based on these preliminary studies that the interference of IBV on the immune response against NDV depends also whether the association between the two vaccines is done just before vaccination or in the manufacturing laboratory.

Effect of associated vaccines on the interference between Newcastle disease virus and infectious bronchitis virus in broilers

The phenomenon of viral interference between live vaccines against Newcastle Disease and infectious bronchitis has been reported since the 50's and many researchers have reported its prejudicial effects on avian immunization. Therefore, this study evaluated the effect of associated vaccines on the interference between Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) in broilers. There were 400 broiler chicks divided into five groups. The groups were submitted to mono or polyvalent vaccinations against IBV and NDV, except for the non-vaccinated control group (CG). Sera were collected at 35 and 45 days of age and submitted to serologic tests to assess antibody levels. It was observed the occurrence of interference in the immune response against NDV by the use of associated vaccines to NDV and IBV; however, the group that was immunized with commercial combined vaccines (IBV+NDV) presented antibody titers to NDV similar to the group that was given only vaccine against NDV. We concluded based on these preliminary studies that the interference of IBV on the immune response against NDV depends also whether the association between the two vaccines is done just before vaccination or in the manufacturing laboratory.

Estudo de parâmetros clínicos e imunitários da vacinação contra a doença de Newcastle e sua importância epidemiológica em periquitosaustralianos (Melopsittacus undulatus)

Foram avaliados parâmetros clínicos, imunitários e epidemiológicos da vacinação contra a Doença de Newcastle em periquitos-australianos (Melopsittacus undulatus) através de dois experimentos. Foram utilizadas amostras vacinais Ulster 2C, B1 e La Sota do VDN. No experimento 1, foram utilizados 72 periquitos australianos com cinco meses de idade, distribuídos em 4 tratamentos de 18 animais cada, num total de três repetições, submetidos a diferentes esquemas imunoprofiláticos. A resposta imune foi avaliada pelo teste de HI, com posterior desafio frente a estirpe patogênica do VDN, aos 11 meses de vida das aves. Em todos os grupos, coletou-se suabes cloacais para pesquisa de RNA viral através da reação de cadeia de polimerase pós Transcrição Reversa (RT-PCR). Independente do grupo experimental, sinais clínicos da reação vacinal não foram observados. Os resultados dos títulos de anticorpos (HI) mostraram que os programas imunoprofiláticos ensaiados foram igualmente eficientes no estímulo da resposta imune humoral. Os periquitos-australianos desafiados mostraram-se refratários à enfermidade clínica com o VDN. Entretanto, ficou caracterizado o estado de portador de VDN nesta espécie decorridos até 19 dias da infecção experimental com este patógeno. No experimento 2, foram utilizadas aves SPF conviventes com periquitos-australianos inoculados com uma estirpe patogênica do VDN. Observou-se a transmissão de vírus patogênico (VDN) dos periquitos-australianos para as aves SPF conviventes decorridos até 19 dias da infecção experimental com este patógeno, o que vem realçar a importância do periquito-australiano como fonte potencial de infecção de VDN para aves domésticas

The clinical, epidemiological, immunological and parameters of vaccination against Newcastle disease in budgerigars (Melopsittacus undulatus) were investigated using 2 experiments. Ulster 2C, B1 and LaSota vaccines strains of the Newcastle disease virus (NDV) were used. In experiment 1, 72 budgerigars were used, and divided into 4 different groups with 18 birds per group. They were submitted to different vaccination programs. The immunological responses in these birds were measured by HI test. These birds were also challenged with a pathogenic VDN strain at 11 months of age. In all the groups, cloacal swabs were collected for RT-PCR. Independent of the group, clinical signs of reaction to the vaccine were not observed. The antibody titers (HI) results showed that the immune vaccine programs adopted were equally efficient in stimulating protective levels of humoral immune responses. Challenged budgerigars were refractory to the NDV clinical disease. However, a NDV carrier state was shown in this species until 19 days after experimental infection. In experiment 2, SPF chickens were housed with budgerigars which were previously inoculated with a pathogenic NDV strain. Therefore, the pathogenic virus (NDV) was transmitted from the budgerigars to SPF birds up to 19 days after challenge, showing the importance of the budgerigars as source of dissemination of NDV to domestic birds

Estudo de parâmetros clínicos, imunitários e do proteinograma sérico da vacinação contra a doença de Newcastle em gansos-da-China (Anser cygnoides) : pesquisa do estado portador do vírus e sua importância epidemiológica

Parâmetros clínicos, imunitários, proteinograma sérico e epidemiológicos da vacinação em gansos-da-China foram avaliados por três experimentos. Amostras vacinais Ulster 2C, B1 e La Sota do VDN foram utilizadas. A importância epidemiológica e pesquisa do estado de portador do VDN também foram avaliadas. No experimento 1, foram utilizados 120 gansos-da-China de um dia a 60 dias de idade, distribuídos em 4 tratamentos com 30 animais, submetidos a diferentes esquemas imunoprofiláticos. Os resultados dos títulos de anticorpos (HI) mostraram que os programas imunoprofiláticos ensaiados foram igualmente eficientes no estímulo da resposta imune humoral. Após o desafio frente a uma estirpe patogênica do VDN, aos 60 dias de vida das aves, em todos os grupos, realizou-se a extração de RNA viral através da reação de cadeia de polimerase pós Transcrição Reversa (RT-PCR). No experimento 2, foram utilizadas aves SPF conviventes com gansos-da-China inoculados com uma estirpe patogênica do VDN, decorridos seis, 10 e 20 dias da infecção experimental, após a infecção com o VDN, nas duas espécies, empregou-se a técnica do RT-PCR. Observou-se a transmissão de vírus patogênico (VDN) dos gansos-da- China para as aves SPF conviventes decorridos até 14 dias da infecção experimental com este patógeno, o que vem realçar a importância do ganso-da-China como fonte potencial de infecção de VDN para aves domésticas No experimento 3, foram determinadas as concentrações séricas das proteínas totais, albumina e globulinas das aves vacinadas e não vacinadas contra a doença de Newcastle. Notou-se que aos 42 dias de idade, de forma geral, os gansos vacinados com as estirpes Ulster 2C, B1 e Lasota apresentaram diferença de forma significativa em relação ao grupo controle para as concentrações séricas de albumina, especialmente o grupo vacinado com a estirpe LaSota

The clinical, epidemiological, immunological parameters and the serum proteinogram of vaccination in Chinese geese were investigated using 3 experiments. Ulster 2C, B1 and LaSota vaccines strains of the NDV were used. In experiment 1, 120 one-day-old Chinese geese were used, and divided into 4 different groups with 30 birds per group. They were submitted to different vaccination programs. The immunological responses in these birds were measured by HI test. These birds were also challenged with a pathogenic VDN strain at 60 days of age. After challenge, in all the groups, tracheal and cloacal swabs were collected for RT-PCR. Independent of the group, clinical signs of reaction to the vaccine were not observed. The antibody titers (HI) results showed that the immune vaccine programs adopted were equally efficient in stimulating protective levels of humoral immune responses. Challenged Chinese geese were refractory to the NDV clinical disease. However, a NDV carrier state was shown in this species until 20 days after experimental infection. The vaccinated groups of Chinese geese did not present any genetic material of virus in the RT-PCR. Therefore, these results show the relevance of vaccination in suppressing a NDV carrier state in the Chinese geese. In experiment 2, SPF chickens housed with Chinese geese which were previously inoculated with a pathogenic NDV strain, developed severe and characteristic NDV lesions and died, after five and 14 days. In experiment 3, the serum proteinogram showed significantly differences for albumin concentrations between the vaccinated and the control group at 42 days of age, especially the birds vaccinated with LaSota strain

Estudo comparativo da virulência de amostras de vacina do vírus da doença de Newcastle em galinhas SPF por meio da análise morfométrica da espessura traqueal

Virulence of three vaccinal lentogenic strains (La Sota, Ulster and VG-GA) of the Newcastle disease virus (NDV) was determined by morphometric analysis of tracheal thickness, in 45-day-old SPF chickens (n=12), free from NDV antibodies. Tracheal thickness was evaluated 1, 2, 3, 4, 6, and 8 days after intratracheal vaccination. La Sota strain induced higher tracheal swelling than the others, during most of the time of the experiment. Maximum swelling of tracheal mucosa occurred at the thirdday after vaccination. At that time, La Sota and Ulster had the same virulence, and both caused higher swelling of tracheal mucosa than VG-GA strain.

A virulência das amostras de vacinas lentogênicas La Sota, Ulster e VG-GA do vírus da doença de Newcastle (VDN) foi determinada por análise morfométrica da espessura da traquéia de galinhas (n=12) de 45 dias de idade, livres de anticorpos anti-VDN, vacinadas por via intra-traqueal. As traquéias foram avaliadas 1, 2, 3, 4, 6 e 8 dias pós-vacinação. A amostra La Sota induziu maior espessamento da traquéia no decorrer de todo período experimental. Ao terceiro dia pós-vacinação, período em que as traquéias se apresentaram mais espessas, as amostras La Sota e Ulster não diferiram em sua virulência, sendo ambas mais virulentas do que a amostra VG-GA, induzindo maior espessamento de traquéia e causando lesões histológicas mais severas.

Estudo dos estados imune e de portador em marrecos de pequim (Anas platyrhynchos) frente ao vírus da doença de Newcastle

Parâmetros imunológicos, clínicos, epidemiológicos e patológicos da vacinação em marrecos de Pequim foram avaliados por 3 experimentos. Para tanto, foram utilizadas amostras vacinais Ulster 2C, B1 e LaSota do vírus da doença de Newcastle (VDN). No experimento 1, foram utilizados 120 marrecos de Pequim de 1 dia de idade, distribuídos em 4 tratamentos de 30 animais cada, submetidos a diferentes programas imunoprofiláticos. A resposta imune foi avaliada pelo teste de HI, com posterior desafio frente a estirpe patogênica do VDN, aos 60 dias de vida das aves. Após o desafio, em todos os grupos, procedeu-se o reisolamento de vírus patogênico em embriões SPF. Independente do grupo experimental, sinais clínicos da reação vacinal não foram observados. Os resultados dos títulos de anticorpos (HI) mostraram que os programas imunoprofiláticos ensaiados foram igualmente eficientes no estímulo da resposta imune humoral. Os marrecos de Pequim desafiados mostraram-se refratários à enfermidade clínica com o VDN. Entretanto, ficou caracterizado o estado de portador de VDN nesta espécie decorridos até 30 dias da infecção experimental com este patógeno. Nos grupos vacinados, o reisolamento de vírus patogênico foi nulo, evidenciando -se assim a importância da imunoprofilaxia na supressão do estado de portador de VDN dos marrecos de Pequim. No experimento 2, aves SPF foram colocadas em contato íntimo com marrecos de Pequim inoculados com uma estirpe patogênica do VDN, decorridos cinco e 14 dias

The clinical, epidemiological, immunological and pathological parameters of vaccination in white Pekin ducks were investigated using 3 experiments. Ulster 2C, B1 and LaSota vaccines strains of the Newcastle disease virus (NDV) were used. In experiment 1, 120 one-day-old white Pekin ducks were used, and divided into 4 different groups with 30 birds per group. They were submitted to different vaccination programs. The immunological responses in these birds were measured by HI test. These birds were also challenged with a pathogenic VDN strain at 60 days of age. After challenge, in all the groups, tracheal and cloacal swabs were collected for re-isolation of the virus in SPF embrionated eggs. Independent of the group, clinical signs of reaction to the vaccine were not observed. The antibody titers (HI) results showed that the immune vaccine programs adopted were equally efficient in stimulating protective levels of humoral immune responses. Challenged white Pekin ducks were refractory to the NDV clinical disease. However, a NDV carrier state was shown in this species until 30 days after experimental infection. The vaccinated groups of white Pekin ducks did not present any virus in the re-isolation of the pathogenic virus. Therefore, these results show the relevance of vaccination in suppressing a NDV carrier state in the white Pekin ducks. In experiment 2, SPF chickens housed with white Pekin ducks which were previously inoculated with a pathogenic NDV strain, developed severe and characteristic NDV lesions and died, after five and 14 days