Biomedical subjects

J E Pearson

Publications and source records attributed to J E Pearson.

115 records · Page 7Linked to original sources

PubMedDate not supplied

Isolation of avian influenza virus (subtype H5N2) from chicken eggs during a natural outbreak.

Avian influenza virus (A/Chicken/Pennsylvania/83; H5N2) was recovered from the yolk, albumen, and shell surface of eggs obtained from naturally infected chicken flocks in Pennsylvania and Virginia. These findings represent the first reported isolation of avian influenza virus from the internal contents of eggs from naturally infected flocks. The need for adequate safeguards to prevent spread of the virus during commercial movement of table and hatching eggs, cracked and "checked" eggs, and egg flats and other materials is emphasized.

Animals↗

PubMedDate not supplied

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)

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PubMedDate not supplied

Eastern equine encephalomyelitis outbreak in coturnix quail.

Eastern equine encephalomyelitis (EEE) was the cause of heavy mortality in coturnix quail (Coturnix coturnix) reared commercially in South Carolina. The birds showed depression, tremor, and partial paralysis that advanced into complete paralysis, torticollis, and death within a few hours. The only consistent lesion on necropsy was a catarrhal enteritis in the duodenal area. The disease spread rapidly to all pens throughout the two houses on the farm in all birds over 2 weeks old, and mortality ranged from 40 to 90% in the various pens within the house. Total mortality exceeded 90,000 birds. Age groups on the farm ranged from 1 day to 8 weeks, at which time the birds went for slaughter. It appears that the initial infection was spread by cannibalism. EEE was diagnosed by isolating the virus in fertile eggs and suckling mice, with subsequent identification by complement-fixation. This is the first documented case of EEE in coturnix quail.

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PubMedDate not supplied

Presence of avian influenza virus (AIV) subtypes H5N2 and H7N1 in emus (Dromaius novaehollandiae) and rheas (Rhea americana): virus isolation and serologic findings.

Avian influenza virus (AIV) subtypes H5N2 and H7N1 were isolated from emus (Dromaius novaehollandiae) and rheas (Rhea americana) in Texas and North Carolina. All the rheas and emus had a history of respiratory disease except one emu, which was clinically normal. The isolates were not pathogenic for chickens and turkeys under the conditions of the experiment. Humoral antibodies to all known hemagglutinin (H) subtypes except H10, H13, and H14 and to all nine neuraminidase (N) subtypes were found in emus and rheas in 11 states. Therefore, emus and rheas are susceptible to infection with several AIV subtypes.

Animals↗

PubMedDate not supplied

Occurrence of velogenic viscerotropic Newcastle disease in pet and exotic birds in 1991.

In 1991, velogenic viscerotropic Newcastle disease (VVND) was diagnosed in domestic psittacine birds in six states: Illinois, Indiana, Michigan, Texas, California, and Nevada. In the first four states, the disease assumed outbreak proportions. The affected psittacine birds--yellow-headed Amazon parrots (Amazona ochrocephala oratrix), yellow-naped Amazon parrots (Amazona ochrocephala auropalliata), cockatiels (Nymphicus hollandicus), and conures (unknown species)--exhibited respiratory and/or central nervous system signs. The velogenic viscerotropic Newcastle disease virus (VVNDV) was isolated from cloacal and tracheal swabs and various tissues, such as the lung, trachea, distal intestine, and spleen. The origin of the birds could not be established. The disease in the six states was promptly controlled, with no evidence that domestic poultry had been exposed. Also, VVNDV was isolated from quarantined birds intended for importation into the United States. Included were 53 moustached parakeets (Psittacula alexandri fasciata), a mynah (Gracula religiosa), a drongo (Dicrurus sp.), and three partridges (family Phasianidae). Groups of birds that yielded VVNDV were denied entry into the United States. Birds that are illegally imported and therefore not tested for the presence of foreign animal pathogens are a potential source of VVNDV and a threat to domestic poultry and caged birds.

Animals↗

PubMedDate not supplied

Survey of the hemagglutinin (HA) cleavage site sequence of H5 and H7 avian influenza viruses: amino acid sequence at the HA cleavage site as a marker of pathogenicity potential.

The deduced amino acid sequence at the hemagglutinin (HA) cleavage site of 76 avian influenza (AI) viruses, subtypes H5 and H7, was determined by reverse transcription-polymerase chain reaction and cycle sequencing techniques to assess pathogenicity. Eighteen of the 76 viruses were isolated in 1993 and 1994 from various sources in the United States. In addition, 34 H5 (4 highly pathogenic [HP] and 30 non-highly pathogenic [non-HP]) and 24 H7 (3 HP and 21 non-HP) repository viruses, isolated between 1927 and 1992, were sequenced and the sequences compared to those in recent isolates. All repository HP H5 and H7 viruses studied had multiple basic amino acids adjacent to the HA cleavage site and most had basic amino acids in excess of the proposed minimum motif B-X-B-R (B = basic amino acids arginine or lysine, X = nonbasic amino acid, R = arginine) that has been associated with high pathogenicity. Of the non-HP viruses studied, 35 of 38 for H5 and 30 of 31 for H7 conformed to the motif B-X-X-R and B-X-R, respectively. Two non-HP H5 viruses had the motif X-X-X-R at the cleavage site and a third had the motif B-X-X-K (K = basic amino acid lysine). One non-HP H7 (A/Pekin robin/CA/30412-5/94) had four basic amino acids (K-R-R-R) adjacent to the cleavage site. Although the Pekin robin isolate did not produce disease in chickens under the conditions of the study it did have the amino acid sequence compatible with that in HP AI viruses and, therefore, is considered potentially HP. This is the first account of an H7 virus that is non-HP in chickens but meets the molecular criterion to be classified as HP.

Amino Acid Sequence↗

PubMedDate not supplied

Susceptibility of pigeons to avian influenza.

Susceptibility to infection with avian influenza virus (AIV) was studied in pigeons inoculated via oculonasal (Experiment 1) or intravenous (Experiment 2) route. Chickens were included as susceptible hosts in both experiments. Two subtypes each of the highly pathogenic AIV (HPAIV; HP CK/PA H5N2 and HP CK/Australia H7N7) and non-pathogenic AIV (NPAIV; NP CK/PA H5N2 and NP emu/TX H7N1) at a dose of 10(5) embryo infective dose per bird were used as inoculum. The pigeons inoculated with HP CK/PA H5N2 or HP CK/Australia H7N7 remained apparently healthy throughout the 21-day observation period, did not shed viruses on 3, 7, 14, and 21 days postinoculation (DPI), and had no demonstrable levels of antibodies on 21 DPI. On the other hand, 9 of 12 chickens inoculated with the HPAIV died of highly pathogenic avian influenza; the viruses were recovered from their respiratory and intestinal tissues, and the surviving chickens had antibodies to AIV. Regarding responses of pigeons to inoculation with NP CK/PA H5N2 or NP emu/TX H7N1, the pigeons remained clinically healthy throughout the 21-day observation period and did not have detectable levels of antibodies on 21 DPI; only one pigeon yielded the NP emu/TX H7N1 on 3 DPI. The virus was isolated from a tracheal swab and was believed to be the residual inoculum virus. Based on the responses of pigeons to NPAIV and HPAIV, it was concluded that the pigeons were resistant or minimally susceptible to infection with HPAIV or NPAIV.

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