key: cord-1052358-xgczt523
authors: Miyamoto, Hideki; Sahara, Keiji; Sugieda, Masaaki
title: Seroepidemiological analysis of influenza pandemics in Shizuoka Prefecture and all Japan
date: 2004-06-30
journal: Int Congr Ser
DOI: 10.1016/j.ics.2004.02.081
sha: b908ffdea7eb1db1a93dd25bab05a72ab9234335
doc_id: 1052358
cord_uid: xgczt523

(1) Seroepidemiological analysis of influenza pandemics (1986–2003) in Shizuoka Prefecture and all Japan revealed differences in geographical, annual, seasonal, and age distributions. (2) For 17 years, the pandemics generally began at the 50th week every year showing over 1.0 patient/clinic, reached the peak at 5th week the following year, and ended over 10–15th week. Two big A/H3N2 pandemics were seen in 1989/1990 and 1997/1998 seasons, claiming over 1 million patients in Japan. (3) As herald strains, A/H3N2 strains (A/Sydney-like) were found in October 1999, and B strains (B/Victoria- and B/Yamagata-like) were detected in July and November 1998 and, in August and December 2000 in Shizuoka. B/Shizuoka/1/98 strain was registered internationally as a vaccine-recommended strain. (4) A/H3N2 and B viruses were detected in 55–78% of flu patients (almost under 10 years) with encephalopathy in 1999/2000 and 78–91% in 2000/2001 by MDCK and reverse transcription polymerase chain reaction (RT-PCR) methods. (5) High hemagglutination inhibition (HI) titers over 40 in 250 persons were shown against A/Sydney/5/97 (H3N2), A/Yokohama/8/98 (H3N2), A/Panama/2007/99 (H3N2) and A/Moscow/10/99 (H1N1) strains, while low titers showed against A/Beijing/262/95 (H1N1) and A/New Caledonia/20/99 (H1N1), and B/Beijing/243/97, B/Shangdong/7/97 and B/Yamanashi/106/98 strains in 1998–2000. (6) In anti-HA titers against A/H3N2, A/H1N1 and B subtypes, clear generation gaps were observed between children (0–19 years), adults (20–59 years) and old men (over 60 years). (7) The pandemics are dependent on host immunity (acquired and vaccinated) and climatic conditions (low temperature, low humidity and limited rainfall), considering highly pathogenic avian influenza (HPAI) viruses (A/H5N1, A/H7N7) like severe acute respiratory syndrome (SARS) corona virus in 2002–2003.

Statistical and epidemiological analyses in weekly data of active dynamic surveillance of influenza and influenza-like illness (ILI) were carried out in Shizuoka Prefecture and all Japan for the last 17 years (1986 -2003) .

Furthermore, virological, serological and genetic analyses were done with regard to (1) pathogen's information -mainly the viral subtypes (vaccine, herald and pandemic/ endemic strains) and (2) patient's information-mainly percentage (%) of hemagglutination inhibition (HI) antibody titers of Shizuoka Prefectural people in order to serve the prediction of usual and new (avian) types of influenza pandemics -interpandemics in the near future in all Japan.

(1) The weekly data were utilized from national and prefectural, active dynamic surveillance of influenza and ILI in 1986-2003, reported due to the new raw of infectious disease control reestablished in 1999 and 2003. (2) Several kinds of test samples from gurgled waters, pharyngeal wipes, sera and liquor derived from babies, young and school children, adults and old men in clinical institutions in Shuizuoka Prefecture were stocked at 4 jC. 

(A) From statistical and epidemiological analyses in weekly data of active dynamic surveillance of ILI in Shizuoka Prefecture and all Japan for the last 17 years (1986 -2003), differences were found in geographical (prefectural), annual and seasonal (winter and others) and age (generation) distributions [1 -3] . During the past 17 years, with the exception of a few seasons, the influenza pandemics usually started at about week 50 every year, showing the incidences over 1.0 patient per clinical institution, reached the peak at about week 5 of the next year, and ended over 10-15th week in Shizuoka Prefecture as well as all Japan [1] [2] [3] . Two biggest pandemics due to A/H3N2 subtype were seen in the 1989/1990 and 1997/1998 seasons, showing over 1 million (10Â10 5 ) patients with ILI in all Japan. Three bigger pandemics of A/H3N2 subtype were also seen in the 1992/1993, 1994/ 1995 and 1998/1999 seasons, showing over 8Â10 5 patients [1 -3] .

(B) The following results [1] [2] [3] were clarified from viral and serological analyses of influenza pandemics in Japan:

(1) By viral and genetic analyses of pandemic subtypes of influenza in Shizuoka Prefecture and all Japan in three recent years (1998 -2000) , A/H3N2 and B subtype strains were isolated as one peak with shoulder in 1998/1999 season, however A/H1N1 and A/H3N2 subtype strains were isolated at the same time as a single peak, namely without viral interference, in 1999/2000 season [1 -3] . 

(1) The early detection of herald strains like B/Shizuoka/1/98 strain in interpandemic periods every year is very important for vaccine-candidated strains and those productive supply in the following seasons [1] [2] [3] .

(2) Low anti-HA antibody (HI) titers under 10 in massive prevention suggest that the next pandemics due to new avian subtypes, e.g., H5N1 in Hong Kong, H7N7 in the Netherlands and other highly pathogenic avian influenza (HPAI) also could be predicted for a world-scale outbreak in the near future among unvaccinated population [1] [2] [3] . 

Sero-epidemilogical analysis of influenza pandemics in Shizuoka Prefecture and all Japan

Study on the analysis of active dynamic surveillance of influenza and the pandemic prediction

Analysis of active dynamic surveillance of influenza and the pandemic prediction

Abbreviations: ILI, influenza-like illness; HPAI, highly pathogenic avian influenza; RT-PCR, reverse transcription polymerase chain reaction; HI, hemagglutination inhibition; SARS, severe acute respiratory syndrome; CoV, coronavirus; NIID, National Institute of Infectious Disease (JAPAN); CDC, Center for Disease Control and Prevention (USA); WHO, World Health Organization.