RESUMO
Fifteen isolations of infectious bronchitis (IB) virus were made from a total of 126 Brazilian poultry flocks of all ages that were examined. These flocks (14 chicken and 1 quail) were experiencing a variety of IB-like conditions including respiratory disease, digestive and kidney problems, and drops in egg production. One of the isolates was of the Massachusetts serotype. The remainder were examined by means of cross-neutralization tests in tracheal organ cultures and were shown to belong to at least four antigenic groups, all different from ones described previously in other countries. Some, but not all, of the flocks from which they were isolated had been vaccinated against IB with vaccines of the Massachusetts serotype. In vivo protection studies showed that the MA5 vaccine (of the Massachusetts serotype) protected well against challenge with four of these isolates, representing the different serotypes reported in this study.
Assuntos
Infecções por Coronavirus/veterinária , Surtos de Doenças/veterinária , Vírus da Bronquite Infecciosa/classificação , Doenças das Aves Domésticas/virologia , Animais , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Galinhas , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Reações Cruzadas , Feminino , Vírus da Bronquite Infecciosa/imunologia , Vírus da Bronquite Infecciosa/isolamento & purificação , Massachusetts , Testes de Neutralização , Oviposição , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/imunologia , Codorniz , Sorotipagem , Vacinas ViraisRESUMO
On the basis of virus isolation and the demonstration of specific neutralising antibody in sera, infectious bronchitis virus (IBV) 4/91 (commonly called 793B) has been shown to be present in broiler, breeder and layer flocks of chickens in many parts of western Europe and also in Thailand and Mexico. These flocks had all been vaccinated against infectious bronchitis and the need for improved methods to control this new virus, still prevalent at least four years after it was first isolated, is discussed.
Assuntos
Galinhas/virologia , Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/classificação , Vírus da Bronquite Infecciosa/isolamento & purificação , Doenças das Aves Domésticas/virologia , Animais , Anticorpos Antivirais/análise , Anticorpos Antivirais/imunologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Coleta de Dados , Surtos de Doenças/veterinária , Europa (Continente)/epidemiologia , Incidência , Vírus da Bronquite Infecciosa/imunologia , México/epidemiologia , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/epidemiologia , Tailândia/epidemiologia , Estados Unidos/epidemiologiaRESUMO
Chickens infected with infectious laryngotracheitis virus (ILTV) responded by producing virus-specific IgG in their sera, which increased steadily in concentration, but with slight fluctuations, until peak titres were reached 40 days post-inoculation (pi), immediately prior to the second challenge. Thereafter, following an initial lag, concentrations continued to increase for 21 days before falling slightly at the end of the experiment. In contrast, peak concentrations of ILTV-specific IgM were reached 6 days pi falling to their lowest levels by day 16, before increasing to a second peak and trough on days 26 and 32, respectively. This cyclical production of ILTV-specific IgM was confirmed in a second experiment. The pattern of production of ILTV-specific IgG, IgM and IgA, detected in tracheal washings, occurred in the same cyclical manner. IgM was produced first, peak concentrations being detected 5 days pi, whereas IgG and IgA did not peak until 10 days pi, with second peaks of each class being detected 25-30 days pi. The possibility that the cyclical antibody class response to ILTV infection is related to the previously reported intermittent pattern of re-excretion of the virus is discussed.
RESUMO
Intramuscular (i.m.) administration of infectious bronchitis virus (IBV) oil-emulsion vaccine (OEV) to IBV-primed or unprimed chickens resulted in the production of zero or minimal concentrations of IBV-specific IgM in the serum, as measured by enzyme-linked immunosorbent assay of gel chromatography fractions. Live-attenuated infectious bronchitis (IB) vaccine given i.m. or by eyedrop stimulated the production of IBV-specific IgM in similar amounts following inoculation by both routes. These levels were comparable to those found in earlier studies following intranasal inoculation with a virulent strain of IBV and confirm that the detection of IBV-specific IgM is a valuable aid to the diagnosis of recent infection. As expected, administration of live-attenuated IB vaccines i.m. or by eyedrop protected the respiratory tract against challenge with virulent virus 24 days later; however, OEV given i.m. did not.
Assuntos
Anticorpos Antivirais/biossíntese , Galinhas/imunologia , Imunoglobulina M/biossíntese , Vírus da Bronquite Infecciosa/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/sangue , Cromatografia em Gel , Cílios/fisiologia , Infecções por Coronaviridae/prevenção & controle , Infecções por Coronaviridae/veterinária , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Injeções Intramusculares/veterinária , Testes de Neutralização , Soluções Oftálmicas , Doenças das Aves Domésticas/prevenção & controle , Organismos Livres de Patógenos Específicos , Traqueia/fisiologia , Vacinação/veterinária , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Vacinas Virais/administração & dosagemRESUMO
Nine isolates of infectious bronchitis (IB)-like viruses were made from 23 flocks (broilers or layers) in Chile experiencing the types of disease problems commonly associated with IBV. Their identity as IB viruses was confirmed. The histological changes they caused in tracheal organ cultures (OC) are described. Serum neutralisation tests performed in embryonated eggs (alpha-method) suggested that four of the isolates were serologically related to the Massachusetts (Mass) serotype of IBV and one to Connecticut. The four other strains were examined further by a serum neutralisation test in OC (ss-method). One was found to be of the Mass serotype but the others were found to be unrelated antigenically to a wide range of IBV serotypes isolated in many countries over a number of years. One of these three strains and the Mass strain, when given intranasally to 8-day-old specified pathogen free chickens together with pathogenic serotypes of E.coli, caused some mortality and considerable morbidity. The H120 vaccine strain was found not to protect completely against challenge with these four strains 21 days later.
RESUMO
The rapid purification of chicken IgM from serum was achieved by affinity chromatography. IgM immunoadsorbent gels were prepared using monoclonal antibodies specific to chicken IgM. Five different eluting agents were compared for the dissociation of the adsorbed IgM; the most convenient for routine purposes was 2 M NaCl, Tris-HCl, EDTA (NTE), as this enabled direct assay of eluents by ELISA without requiring the intermediate step of dialysis, which the other eluting agents did. Eluents prepared from sera obtained from infectious bronchitis virus (IBV) and infectious laryngotracheitis (ILTV)-infected chickens, together with samples of the same serum fractionated by gel chromatography, were tested by ELISA for virus-specific antibodies and to confirm the identity of the antibody class. In the case of both IBV and ILTV, similar results were obtained using immunoaffinity and gel chromatography. IBV-specific IgM, as determined by both methods in the ELISA, reached its highest concentration at the 8th day after inoculation and was virtually absent by the 24th day, whilst the highest concentration of ILT-specific IgM was detected at 6 days and no or little IgM was present at 16 days after inoculation. Purification of serum IgM by affinity chromatography followed by ELISA was considered suitable for routine serological diagnosis of IB and ILT, since the time required to complete the assay (3 hours) was considerably less than that for gel chromatography and many samples could be assayed simultaneously.