| dc.description.abstract | Ducks are the natural reservoir of influenza A virus and the central host for highly pathogenic
avian influenza (H5N1), while domestic ducks rearing in semi-scavenging system could serve as
re-assortment vessels for re-emerging new subtypes of influenza viruses. The present active
surveillance study hereby reports the molecular detection of different subtypes of avian influenza
viruses (AIVs) in semi-scavenging ducks. A total of 700 cloacal swabs were collected from semiscavenging
ducks
from
six
selected
haor
basin
areas
of
Sylhet
division
of
Bangladesh
during
the
period
from
January
2015
to
December
2015.
AIVs
were
identified
from
collected
swab
samples
by
detecting M gene using real-time RT-PCR (RT-qPCR). Sub-typing of AIV positive samples
were performed using RT-qPCR specific for H5, H7 and H9 genes. Out of 700 samples 12
(1.71%) were found positive for AIVs. Sub-typing of AIV positive samples (n=12) revealed that
7 (58.33%) samples were positive for H9 sub-type and 5 samples were negative for the selected
genes (H5, H7, H9). Our results were validated by detecting the same genes after propagation of
virus in embryonating chicken eggs from positive samples. Based on our findings, we conclude
that semi-scavenging ducks reared in hoar areas acts as a carrier of low pathogenic AIVs.
Although H9 subtype of AIV is low pathogenic and has lower risk for human, it is alarming that
this virus may change its pathogenicity in ducks by re-assortment and may become highly
pathogenic. Our large data set from six migratory bird sanctuaries might provide a strong
background for furthermore studies of AIV prevalence, evolution and ecology. | en_US |
