Lack of antigenic relationships between avian pneumovirus and four avian paramyxoviruses.

Avian paramyxoviruses (PMVs) and avian pneumovirus (APV) belong to the family Paramyxoviridae. Antigenic relationships between PMVs were shown previously, hence, this study was designed to investigate possible antigenic relationships between APV and four avian PMVs (PMV-1, PMV-2, PMV-3, and PMV-7). Enzyme-linked immunosorbent assay (ELISA), hemagglutination inhibition (HI) test, and virus neutralization (VN) test in chicken embryos and in Vero cells were used. The HI test was performed with the PMVs as antigens against the APV and PMVs antisera. The ELISA and VN test in chicken embryos were performed with PMVs and APV antigens and antisera. The VN test in vero cells was performed with the APV as an antigen against the PMV antisera. All the viruses were isolated in the United States or Canada. No antigenic relationships between APV and the PMVs were detected by the described tests.

Pathogenicity, transmissibility, and tissue distribution of avian pneumovirus in turkey poults.

The pathogenicity, transmissibility, tissue distribution, and persistence of avian pneumovirus (APV) in turkey poults were investigated in three experiments. In the first experiment, we inoculated 2-wk-old commercial turkey poults oculonasally with APV alone or in combination with Bordetella avium. In the dually infected group, clinical signs were more severe, the virus persisted longer, the bacteria invaded more respiratory tissues, and the birds had higher antibody titer than the group exposed to APV or B. avium alone. In the second experiment, we studied the distribution of APV in different tissues in experimentally inoculated 2-wk-old commercial turkey poults. Only samples from sinuses, tracheas, and lungs were positive for APV by both reverse transcriptase-polymerase chain reaction and virus isolation. In the third experiment, we studied the ability of APV to spread among birds in 1-wk-old commercial turkey poults inoculated oculonasally. The virus was isolated and the viral RNA was detected in the inoculated and direct contact birds. The virus was not isolated, viral RNA was not detected, and no antibodies were detected in the indirect contact birds. These birds were placed in different cages in the same room where the airflow was directed from the infected toward the uninfected indirect contact group.