Viscerotropic velogenic Newcastle disease virus replication in feathers of infected chickens

Newcastle disease viruses (NDVs) cause systemic diseases in chickens with high mortality. However, little is known about persistence of NDVs in contaminated tissues from infected birds. In this study, we examined viral replication in the feather pulp of chickens inoculated with viscerotropic velogenic NDV (vvNDV) genotype VII. Reverse transcription real-time PCR and immunohistochemistry were used to investigate viral persistence in the samples. vvNDV was detected in the oropharynx and cloaca and viral antigens were detected in the feathers, suggesting that feathers act as sources of viral transmission.

Assessment of Newcastle and infectious bronchitis pathogens, and Salmonella spp. in wild birds captured near poultry facilities / Pesquisa de Salmonella spp., de doença de Newcastle e de bronquite infecciosa em aves silvestres capturadas próximo a instalações avícolas

Aves de vida livre podem ser carreadoras e disseminadoras de agentes patogênicos e representarem um risco para galinhas de produção. O objetivo deste trabalho foi verificar em aves de vida livre a presença de anticorpo contra: Salmonella Pullorum (SP), vírus da doença de Newcastle (VDN) e vírus da bronquite infecciosa (VBI), bem como a presença de Salmonella spp. De 48 aves de vida livre capturadas nas imediações de uma granja avícola, no norte do Estado de São Paulo, em 2005 e 2006, foram colhidos soros para realização de testes de soroaglutinação rápida em placa (SAR) para SP, inibição de hemaglutinação (HI) para o VDN e soroneutralização (SN) para VBI. Foram colhidos fragmentos de fígado, baço e ovários/testículos, todos cultivados juntos como um pool e conteúdo intestinal separado, para cultura de Salmonella spp. Todas as amostras foram negativas para a doença de Newcastle e bronquite infecciosa. Quanto à Salmonella Pullorum, pela técnica de SAR, a amostra de Theristicus caudatus foi positiva. No exame bacteriológico, foi isolado o agente em três aves: Theristicus caudatus (Salmonella Muenchen), Zenaida auriculata (Salmonella Enteritidis) e em Cariama cristata tanto Salmonella Muenchen como Salmonella Saintpaul.

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.

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.

ELISA indireto para detecção de IgG antivírus da doença de Newcastle em soro de codorna / Indirect ELISA for the detection of IgG specific to Newcastle disease virus in quail serum

An indirect ELISA for the detection of japanese quail IgG specific to Newcastle disease virus (NDV) was developed. The secondary anti-quail IgG was produced in Balb/c mice, by inoculating Freund's complete adjuvant emulsified japanese quail-IgG extract. The purification of IgG was achieved using the caprilic acid method. The ELISA was compared to the haemagglutination-inhibition (HI) test for antibodies to NDV. ELISA cut-off point was established through TG-ROC analysis. Total correlation was observed between the ELISA and the HI, being the ELISA efficient in the identification of positive and negative sera, with high sensitivity and specificity (100 percent). These results validate the use of the indirect ELISA as an alternative for the detection of NDV-specific IgG in japanese quail sera, with the advantage of high sensitivity and automation

Registration of spontaneous photon emission from virus-infected cell cultures: development of experimental system.

Detection of spontaneous photon emission from virus-infected cells was attempted using cell monolayer cultures prepared from the established cell lines differing by origin and sensitivity to viruses. The experimental system was elaborated permitting maintenance of the cell monolayer cultures grown upon quartz slides placed inside quartz cuvettes within the photomultiplier chamber during prolonged time periods (till 24-36 hr) covering the whole virus multiplication cycle. Rich nutritive medium was employed, providing undisturbed cell viability and virus-induced cytopathic effect (CPE) development during such prolonged experiment, each ingredient of the medium being checked as potential parasitic emitter or extinguisher of the cell-specific emission. As presupposed 'positive control', the in vivo cultivated chorio-allantoic membranes (CAM) of 10-days-old chick-embryonated eggs were used. The virus-infected CAMs showed specific peculiarities of the emission dynamics as compared to monotonous dynamics shown by non-infected CAMs. Similar dynamic regularities were observed in cell monolayer cultures containing much lesser (by order) number of cells per exposed sample. Using the elaborated system, some specific changes in the virus-infected cells were found, being correlated with two stages of virus replication cycle: the initial stage, synchronous penetration of the pre-adsorbed virus inside the cell, and a later stage, characterized by intensive CPE manifestations.

Effects of ultraviolet radiation on structural components of enveloped RNA viruses

The interaction of ultraviolet radiation and virus particles of Western Equine Encephalomyelitis Virus (WEE) and Newcastle Disease Virus (NDV) which have respectively RNA of positive (RNA+) and negative (RNA-) polarity as genomes, was studied using purified particles. The purified virus preparations were irradiated at a range from 1,000 to 6,000 joules per m2 with posterior analysis of their propagation in primary cell cultures of chicken embryos. It could be observed that a radiation dose of to 4,500 joules per m2 could induce 10(9) TCID50 per ml as minimal loss of titer for WEE virus and NDV. The hemagglutination assay was used as a toll to evaluate the alterations caused by UV radiation on the molecular arrangement of virus proteins. Alterations of the virus hemagglutinating activity were only observe when radiation levels higher than 6,000 joules per m2 were used. The results from hemolysis assays showed the importance of the loss of the envelope integrity and the damages to nucleoprotein structures during the inactivation process, when we used radiation doses higher than 6,000 joules per m2. This model of study can increase our comprehension of the radiation effects on the cell physiology and biological components of the cell membranes.

Prevalência do vírus da doença de Newcastle em uma comunidade de aves ornamentais / Prevalence of the Newcastle disease virus in an ornamental bird flock

O estudo de vigilância virológica de uma comunidade de pássaros num período de três anos, resultou no isolamento de 21 amostras de vírus da doença de Newcastle (NDV), entre 360 materiais fecais examinados. Estes isolamentos ocorreram de maio a setembro e de novembro a janeiro, com mais alta percentagem nos primeiros dois anos de investigaçäo (1981/82 e 1982/83). Os pássaros aparentemente saudáveis tiveram suas fezes coletadas e a presença viral foi investigada pela inoculaçäo em ovos embrionados. Os vírus isolados foram identificados pro inibiçäo de hemaglutinaçäo (HI)

Newcastle disease virus: some biological characteristics of twelve samples isolated in Brazil

Foram estudadas algumas propriedades biológicas de 12 amostras de virus de Doença de Newcastle (VDN), isolados no Brasil. De acordo com o indice de patogenicidade intracerebral(IPIC), três amostras foram consideradas Lentogênicas, três mesogênicas e 6 velogênicas. As amostras foram diferenciadas entre si pela comparaçäo da termoestabilidade, tempo de de eluiçäo e a habilidade de aglutinar hemácias de cavalo. Dentre as amostras Lentogênicas dois dos isolados se assemelharam a amostra vacinal LaSota e um a amostra B1. Nenhum dos isolados se assemelhou a amostra 2C Ulster. O isolado ,esogênico obtido de perus pode ser diferenciado dos dois outros isolados mesogênicos obtidos de galinha. As amostras velogênicas foram divididas em 4 grupos: eluiçäo rápida - termoesteabilidade - HA (+) para hemácias de cavalo (uma amostra); eluiçäo rápidatermoestabilidade - HA (-) para hemácias de cavalo (trê s amostras); eluiçäo rápida - termosensibilidade - HA (-) para hemácias de cavalo (uma amostra); eluiçäo lenta - termosensibilidade - HA (-) para hemácias de cavalo ( uma amostra)