Pathogenicity and cross-protection of pigeon paramyxovirus-1 and Newcastle disease virus in young chickens

Avian paramyxovirus-1 (PMV-1) isolates from Delaware racing pigeons were compared with Newcastle disease virus (NDV) in pathogenicity and cross-protection studies in young chickens. The pathogenicity of pigeon PMV-1 isolates was more closely related to mesogenic (Roakin) NDV than to lentogenic (La Sota) or velogenic (Texas GB) NDV strains. Pigeon PMV-1 produced 100% mortality in 1-day-old NDV-susceptible chickens following intratracheal and intracerebral inoculation. Laboratory tests often used in conjunction with chicken pathogenicity procedures for patho-typing NDV gave conflicting results. Pigeon PMV-1 isolates produced large clear plaques (up to 3.5 mm) in chicken-embryo-fibroblast cultures. Chicken embryo mean death times were considerably greater for pigeon PMV-1 (88 and 109 hr) than for Roakin (66 hr) and Texas GB (48 hr). B1 strain NDV and pigeon PMV-1 produced complete cross-protection in challenge studies in chickens. Extensive cross-reaction between pigeon PMV-1 and NDV occurred in hemagglutination-inhibition tests using polyclonal antisera. However, pigeon PMV-1 and NDV were readily distinguishable using a NDV monoclonal antibody, 2F12.     

Efficacy of viable and inactivated Newcastle disease virus vaccines in turkeys

Market turkeys spray-vaccinated at 20 days of age with viable Newcastle disease virus (NDV) vaccine and challenged 7 weeks postvaccination failed to yield NDV by tracheal swabbing 4 days postchallenge but demonstrated serologic evidence of infection. Birds vaccinated subcutaneously with inactivated oil-emulsion (OE) NDV vaccine had virologic and serologic evidence of infection. Breeder hens vaccinated by spray with commercial La Sota vaccine at 19 weeks of age and revaccinated subcutaneously with OE vaccine at 32 weeks of age had an adequate level of resistance against a drop in egg production but demonstrated serologic evidence of infection when challenged with velogenic NDV at 38 weeks of age.     

Characterization of Newcastle disease virus (avian paramyxovirus-1) isolated from pigeons

Newcastle disease virus (avian paramyxovirus-1) was isolated from pigeons in 12 states between May 1984 and December 1985. One of the isolates was from a feral pigeon; the remainder were from privately owned pigeon lofts. Use of monoclonal antibodies showed seven of the eight isolates tested to be indistinguishable from the 1982 and 1983 Great Britain and European isolates. Clinical signs were paralysis, torticollis, tremors, incoordination, and death. Pigeons inoculated with the paramyxovirus-1 isolates intravenously or intramuscularly developed clinical disease identical to that described for natural infection; however, only one pigeon inoculated intranasally developed clinical signs. The mean death time for inoculated pigeons was 9.5 days, with a range of 4 to 25. Virus was shed for up to 20 days. Primary lesions observed on necropsy were gastroenterocolitis and pancreatic necrosis. Chickens experimentally infected by the cloacal, intranasal, or caudal thoracic air-sac route remained healthy. However, the intracerebral pathogenicity index (ICPI) in day-old chickens was similar to that observed with velogenic Newcastle disease virus isolates. Four of six isolates inoculated intravenously into 6-week-old chickens induced neurotropic disease.     

Isolation of a paramyxovirus-3 from turkeys with respiratory tract disease in Germany]

In fattening turkeys 2.5 weeks of age a respiratory disease associated with coughing, nasal discharge and swelling of the infraorbital sinus was seen. Pathological findings in diseased turkeys were sinusitis, tracheitis, pneumonia and aerosacculitis. Virological investigations of trachea, kidney and intestine in SPF-chicken embryos resulted in the isolation of a virus, that could be identified as a paramyxovirus type 3 due to chemical-physical, biological, morphological and immunological properties. The pathogenicity of the isolate 324/86 to turkeys was shown in a test with three weeks old turkey poults. This is the first isolation and identification of a paramyxovirus-3 of turkeys in Germany.     

An evaluation of Newcastle disease virus spray vaccination programs of market turkeys

Commercial market turkeys that were spray-vaccinated at 2 to 3 weeks of age with viable Newcastle disease virus (NDV) vaccine usually did not develop high or persistent levels of serum antibody as detected by the hemagglutination-inhibition test. Vaccinated turkeys exhibited a satisfactory level of resistance to infection and clinical disease when challenged by the oculonasal or aerosol route at 2 weeks post-vaccination, and they resisted clinical disease when challenged at 6 weeks, but the level of protection diminished by 10 weeks post-vaccination. It is suggested that market turkeys produced in an NDV-enzootic area may require two or more NDV vaccinations by spray during their growing period in order to be adequately protected against natural NDV infection.     

Characterization of a battery of monoclonal antibodies for differentiation of Newcastle disease virus and pigeon paramyxovirus-1 strains

Twenty monoclonal antibodies (MCAs) prepared against the velogenic GB-Texas strain of Newcastle disease virus (NDV) and the type 1 pigeon paramyxovirus (PPMV-1) were characterized and examined as potential immunodiagnostic reagents. All MCAs generated were found to bind specifically, but with varying reactivity, to various NDV strains in direct binding assays. In addition, MCA 15C4 neutralized and inhibited hemagglutination (HA) of all lentogenic, mesogenic, and velogenic NDV strains tested but not the PPMV-1 strain. Antibody 10D11 also inhibited HA activity, but inhibition was more selective and limited to the mesogenic and domestic or indigenous velogenic strains of NDV. MCA 79 reacted in all serologic assays with an antigenic site common to all serotype 1 avian paramyxoviruses. Passive immunization studies involving three different neutralizing MCAs (35, 79, and 15C4) showed that enhanced, but not complete, protection against virulent NDV challenge was provided when the three MCAs were administered in combination.     

Genetic variation in resistance of turkeys to experimental infection with Newcastle disease virus.

Seven hundred eighty male and female turkeys representing four genetic lines were challenged in four experiments with the Texas GB strain of Newcastle disease virus (NDV). The lines of turkeys included two randombred control lines (RBC1 and RBC2), a subline (E) of RBC1 selected for increased egg production, and a subline (F) of RBC2 selected for increased 16-week body weight. Mortality in turkeys of subline F (32.5%) was significantly higher than that in turkeys of line RBC2 (15.8%), subline E (17.5%), and line RBC1 (18.4%). At the end of each experiment, surviving birds were tested for antibody to NDV using the enzyme-linked immunosorbent assay (ELISA) and hemagglutination-inhibition (HI) test. Turkeys of subline E and line RBC1 had significantly lower ELISA antibody titers than those of subline F and line RBC2. Subline F had the highest HI antibody titers, followed in decreasing order by lines RBC2 and RBC1 and subline E. No apparent correlation was found between antibody response and mortality after NDV challenge.     

蛋鸡新城疫病毒的分离与初步鉴定

采用鸡胚接种法从河北一些蛋鸡场分离到3株病毒,分别标号为WJ1、WJF2和WJF3.经血凝、血凝抑制试验及血清学中和试验鉴定3株分离毒株均为新城疫病毒;鸡胚半数致死量测定,WJ1株毒价为107.3ELD50/0.1 mL,WJ2株和WJ3株毒价分别为107.9ELD50/0.1 mL.动物回归试验鸡的临床表现与自然病例基本一致.再用分离毒攻ND Ⅳ系疫苗免疫鸡,显示ND Ⅳ系疫苗可以保护WJ1和WJ3分离毒株,而不能保护WJ2分离毒株.     

Pathology of the trachea in turkeys exposed by aerosol to lentogenic strains of Newcastle disease virus

Five groups of 4-week-old turkey poults were each infected by aerosol with a different lentogenic strain of Newcastle disease virus. Four days postinfection, sections of tracheas were collected for histopathologic characterization and virus titration. The most prominent lesions were fibrinopurulent exudate in tracheal lumens, hyperplasia of epithelial cells, and infiltration by lymphocytes. All strains multiplied to high titers and produced similar microscopic lesions, but the number of poults with severe microscopic lesions varied among groups.     

The comparative antigenic characterization of Newcastle disease virus strains isolated in Kenya and Kazakhstan

Twenty six Newcastle disease viruses--12 reference strains and 14 strains isolated in Kenya and Kazakhstan--were characterized by means of a large panel of 38 monoclonal antibodies (MAB) directed against all the three envelope proteins: matrix, hemagglutinin-neuraminidase and fusion. The essential distinctions were revealed between the viruses isolated in Kenya and Kazakhstan while the differences amongst the viruses belonging to the same local group were much smaller. The heterogeneity amongst the viruses isolated in Kenya was more expressed as compared to the Kazakhstanian strains.     

Pathology of velogenic Newcastle Disease virus infection in turkeys.

Twenty-four 4-week-old poults, free from Mycoplasma meleagridis and M. gallisepticum, were inoculated with a velogenic viscerotropic strain of Newcastle disease virus. Clinical signs (gasping, coughing, and dyspnea) developed 4-5 days postinoculation, continued until nervous derangement appeared, and then (usually 3 days after initial clinical signs appeared) declined in severity. Prominent nervous signs were paresis and paralysis of the extremities, with pronounced head-shaking. The most constant gross lesions detected involved the airsacs. The abdominal sacs of a few poults contained a large accumulation of yellowish, cheesy exudate and there was cloudiness of the thoracic airsacs of all inoculated poults. A few turkeys had tracheitis with some catarrhal exudates and casts in the lower part of the tracheal lumen. Congestion of lepto-meningeal vessels usually correlated with the severity of the nervous signs. The histologic lesions were characterized by both degenerative and proliferative changes with predominantly mononuclear cell and heterophil infiltrations throughout the body. The obvious lesion seen in the recovery stage of the disease was proliferation of lymphofollicular nodules in the parenchymatous organs.     

Experimental infection of turkeys with avian pneumovirus and either Newcastle disease virus or Escherichia coli

Avian pneumoviruses (APVs) are RNA viruses responsible for upper respiratory disease in poultry. Experimental infections are typically less severe than those observed in field cases. Previous studies with APV and Escherichia coli suggest this discrepancy is due to secondary agents. Field observations indicate APV infections are more severe with concurrent infection by Newcastle disease virus (NDV). In the current study, we examined the role of lentogenic NDV in the APV disease process. Two-week-old commercial turkey poults were infected with the Colorado strain of APV. Three days later, these poults received an additional inoculation of either NDV or E. coli. Dual infection of APV with either NDV or E. coli resulted in increased morbidity rates, with poults receiving APV/NDV having the highest morbidity rates and displaying lesions of swollen infraorbital sinuses. These lesions were not present in the single APV, NDV, or E coli groups. These results demonstrate that coinfection with APV and NDV can result in clinical signs and lesions similar to those in field outbreaks of APV.     

Efficacy of oil-emulsion vaccines prepared with pigeon paramyxovirus-1, Ulster, and La Sota Newcastle disease viruses

Three strains of avian paramyxovirus-1 virus (PMV-1) were used to prepare four experimental monovalent oil-emulsion vaccines. A pigeon PMV-1 isolate (PPMV-1) and the Newcastle disease virus strains La Sota and Ulster were used to prepare four pools of beta-propiolactone-inactivated allantoic fluid for the vaccines. Groups of susceptible white rock chickens and racing homing pigeons were vaccinated subcutaneously with one of the vaccines, and their serologic responses were determined using the hemagglutination-inhibition (HI) test at frequent intervals up to 9 weeks postvaccination. Pigeons were challenged after 10 weeks with a virulent PPMV-1 isolate given intravenously, observed for signs of disease for 5 weeks, and then tested for secondary serologic HI responses. The HI responses were measured using the three strains of virus as HI test antigens. The titers were generally greater when the hemagglutination antigen used in the test was homologous with the antigen used to prepare the vaccine. All vaccines protected pigeons against morbidity and death but not against infection with the challenge virus. The shedding of PPMV-1 challenge virus from PPMV-1 vaccinates was greatly reduced 6 days after challenge.