چكيده لاتين :
Background: The pandemic and regional influenza outbreaks
resulting from antigenic variation of influenza viruses
have been the subject of numerous studies which are crucial
to the preparation of the vaccine. Frequent global winter outbreaks
of influenza viruses require a constant surveillance of
emerging influenza variants in order to develop efficient influenza
vaccine.
Methods: This study was conducted from December 2004 to
March 2005, during an outbreak of influenza in 300 children
of one to 15-year-old. MOCK cells grown in microwell
plates inoculated with pharyngeal swabs. Hemagglutination
(HA) of guinea pig erythrocytes by viral isolates was used for
initial screening of influenza viruses. The final viral identification
was performed by HA inhibition test using reference antisera
prepared against WHO reference antigens.
Results: Based on the results of HA tests with culture fluid of
MOCK inoculated with 300 pharyngeal swabs, 31 (10.3%) of
the specimens were suspected to contain influenza viruses of
which 10 proved to be either A/H1N1or A/H3N2 subtypes. by
reacting against aforementioned antisera in HA inhibition test.
H3N2 subtype prevailed until January 2005 and mostly
affected children of younger age, whereas viruses emerging
subsequently were only of H1N 1 subtype and predominantly
isolated from children of older age.
Conclusion: A/H3N2 isolate appears to be antigenically different
from corresponding reference antigen. This is evident by a
16-fold reduction in antibody titer by using reference antiserum
against A/H3N2 Isolate (I :8), as compared to that of reference
antigen antibody (I: 128).
