ABSTRACT
Purpose: Influenza virus is a major cause of human respiratory infections and responsible for pandemics and regional outbreaks around the world. This investigation aims to determine the prevalent influenza genotypes during 2005-2007 outbreaks in Shiraz, the capital city of Fars province, southern Iran and compare the results obtained with those of previous study. Materials and Method: Of the 300 pharyngeal swabs collected from influenza patients, 26 were found to be positive by culture and hemagglutination (HA) assays. Typing and subtyping of the isolates carried out by using multiplex RT-PCR and phylogenetic analysis performed on isolated HA genes using neighbour-joining method. Result: Out of 26 positive isolates 12 and 14 were H1N1 and H3N2 respectively. The phylogenetic and amino acid sequence analyses of our H1N1 isolates showed 99-100% genetic resemblance to A/NewCaledonia/20/99 (H1N1) vaccine strain. Most of the Iranian H3N2 isolates varied form A/California/7/2004 vaccine strain in 20 amino acids of which positions 189,226 and 227 were located in antigenic sites of HA1 molecule. These substitutions were not observed in any of the H3N2 subtypes from the same region reported previously. Conclusion: The H3N2 subtype strains prevalent during the 2005/7 influenza outbreak in southern Iran demonstrated a drastic antigenic variation and differed from A/California/7/2004 vaccine strain. The H1N1 subtypes showed a notable resemblance to A/NewCaledonia/20/99 vaccine strain and therefore were predicted to be capable of conferring sufficient immunity against H1N1 subtypes.
ABSTRACT
PURPOSE: The newly described human metapneumovirus (hMPV) has been recently discovered as an etiological agent of acute respiratory infections (ARTI) in infants and children. The aim of this study was to determine the prevalence of hMPV and its potential role as causative agent of ARTI in Ahwaz children. METHODS: In the present study, we examined 124 nasal swabs from infants affected by ARTI for the presence of hMPV by RT-PCR technique. RESULTS: Sixty-eight out of 124 (54.4%) cases were positive for hMPV which is the highest incidence of hMPV ever reported in the world, 94.1% of positive cases belonged to genotype A; whereas no B genotype was detected. Our positive hMPV children were affected by upper (URTI) as well as lower respiratory tract infection (LRTI); however, LARTIs had higher prevalence. CONCLUSIONS: We suggest a probable role of F protein alteration as the causative agent for the highest prevalence of hMPV infection among Ahvaz children.