[show abstract][hide abstract] ABSTRACT: H4N8 subtype avian influenza viruses were isolated from shorebirds in eastern Hokkaido. All the isolates shared >99.7% nucleotide homology, and all the viral genes except for PB1 were highly related to those of A/red-necked stint/Australia/1/04. Thus, the isolates were regarded as PB1 reassortants. The most similar PB1 gene was identified in A/mallard/New Zealand/1615-17/04 (H4N6) with nucleotide homology of 90.9%. BALB/c mice intranasally inoculated with the H4N8 isolates developed severe respiratory disease, which eventually led to death in some mice. The virus was isolated from the lungs, and viral antigen was detected in the lungs with pneumonia. Other H4 subtype viruses tested did not cause any symptoms in mice, although these viruses were also isolated from the lungs. The PB2 gene of the H4N8 isolates contains K482R, but not the E627K or D701N substitutions. The PB1-F2 gene of the isolates consists of a 101-amino acid unique sequence, but lacks the N66S mutation.
[show abstract][hide abstract] ABSTRACT: The epidemiological information has obtained on avian influenza virus (AIV) in eastern Hokkaido, Japan, where AIV surveillance has not been performed. Cloacal or fecal samples obtained from migratory water birds were screened for AIV both by real-time reverse transcriptase polymerase chain reaction to detect the influenza A virus matrix (M) gene and by egg inoculation. Between 2007 and 2009, a total of 2,488 samples were collected from various avian species in Abashiri, Kushiro, Nemuro and Tokachi districts of eastern Hokkaido. AIVs were isolated from 18 of those samples (0.7%). No AIV was isolated from the 1,449 samples collected in Abashiri, Kushiro and Nemuro districts, although 6 were positive for the M gene by RRT-PCR. In contrast, 52 (5.0%) of the 1,039 samples collected from ducks in Tokachi district were M gene positive; AIVs were isolated from 18 of those samples (1.7%). The isolates included H3N5 (1 isolate), H3N6 (1), H3N8 (9), H4N2 (1), H4N6 (2), H6N5 (1), H6N8 (1), and H11N3 (2) subtypes. H3N5 and H11N3 subtypes have not been frequently isolated, and our study is the first to report H3N5 and the second to report H11N3 in Japan. Phylogenetic analysis revealed that the M genes of all isolates belonged to the Eurasian lineage.
Journal of Veterinary Medical Science 02/2011; 73(2):209-15. · 0.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: A latex agglutination test (LAT) was developed for detecting antibodies against avian influenza virus. The recombinant avian influenza virus nucleoprotein expressed in Escherichia coli was purified, coupled with latex beads, and used as an antigen for the LAT. The LAT was capable of detecting anti-avian influenza virus antibodies irrespective of the avian-influenza subtype, and in most cases, the results correlated with the results of an agar gel precipitation test (AGPT). However, in comparison with the AGPT, the LAT could detect the anti-avian influenza virus antibodies for a longer period of time after the infection. The nonspecific agglutination observed in uninfected chicken sera was resolved by pretreating the sera with dried chicken-liver powder for 1 h. The LAT is easy to perform, and even after considering the time required for pretreatment of the serum, the total time required for obtaining the results is reduced in comparison to the time required in the case of the AGPT. This easy and rapid LAT is considered to be useful for monitoring avian influenza virus infection in the field.
Journal of virological methods 08/2009; 161(2):259-64. · 2.13 Impact Factor