Virus isolations from pet birds submitted for importation into the United States.

From October 1973 to September 1981, 2,882,111 birds were offered for importation into the United States. All were quarantined for 30 days, and specimens were submitted to the laboratory for virus-isolation studies. Viruses were isolated from specimens from 26.3% (598/2,274) of the quarantined lots of birds. Viscerotropic velogenic Newcastle disease virus (VVNDV) was isolated from 141 lots. Nonviscerotropic velogenic Newcastle disease virus (VNDV) was isolated from six lots. All VVNDV- and VNDV-positive lots were refused entry. The percentage of lots refused entry declined from 31.6% in 1974 to 2.9% in 1981. Mesogenic Newcastle disease virus (NDV) was isolated from three lots, and lentogenic NDV was isolated from 23 lots. Lots positive for mesogenic and lentogenic NDV were allowed to enter the United States. Hemagglutinating (HA) viruses other than NDV were isolated from 24.5% (373/1,521) of the lots imported through privately owned quarantine facilities. Of the 8,563 HA viruses isolated, 1,558 were selected for identification. Forty-six percent were identified as paramyxovirus (PMV)-2, 34% were PMV-3, and 20% were influenza A viruses possessing the hemagglutinin subtypes H3, H4, H7, and H10 and the neuraminidase subtypes N1, N6, N7, and N8. The frequency of PMV-2 and PMV-3 isolations fluctuated from year to year, whereas the frequency of isolations of influenza A viruses decreased from 64% in 1974 to 0.2% in 1981. Viruses that did not agglutinate chicken red blood cells were isolated from 52 lots. Psittacine herpesvirus (Pacheco's disease) was isolated from 25 lots of psittacines. Viruses identified by electron microscopy as reoviruses were isolated from 24 lots.(ABSTRACT TRUNCATED AT 250 WORDS)