MOLECULAR EPIDEMIOLOGY OF INFLUENZA A/H3N2 VIRUS IN A TROPICAL COUNTRY, SINGAPORE

Abstract

INFLUENZA A/H3N2 GENOME SEQUENCING WAS PERFORMED FOR 241 CLINICAL SPECIMENS COLLECTED FROM LOCAL HOSPITALS AND PRIMARY CARE CLINICS BETWEEN 2009 AND 2013, TO ALLOW MOLECULAR CHARACTERIZATION OF THE H3N2 VIRUSES FROM A TROPICAL COUNTRY, SINGAPORE. NOTABLY, WE FOUND UP TO 42% OF THE H3N2 VIRUSES EXPERIENCED AT LEAST ONE MUTATION IN ANY SEGMENT AFTER A SINGLE PASSAGING OF THE CORRESPONDING PRIMARY CLINICAL SAMPLES IN MDCK CELLS. MORE INTERESTINGLY, A DRUG RESISTANT-RELATED MUTATION, D151G/N WAS FOUND IN 23% OF THE SINGLE-PASSAGED VIRUSES. BESIDES, THE GENOME SEQUENCES OBTAINED IN THIS STUDY SERVED AS A PRIME DATABASE PLATFORM FOR OTHER STUDY PURPOSES, INCLUDING MOLECULAR SURVEILLANCE TO MONITOR FOR DRUG RESISTANCE MUTATIONS, SEVERE DISEASE MARKERS/STRAINS, AND POSSIBLE INCREASED CLINICAL SEVERITY DUE TO LOWER VACCINE MATCHING IN THE POPULATION WITHIN THE STUDY PERIOD. OF NOTE, ALL THE SAMPLES INCLUDED IN THESE ANALYSES WERE SEQUENCED DIRECTLY FROM THE CLINICAL SAMPLES WITHOUT CULTURING TO