Pandemic (H1N1) 2009
According to the National Epidemiological Surveillance for Infectious Diseases
in Japan, the numbers of reported cases of the Influenza like Illness (ILI)
have been increasing in the 38th epidemiologic week (September 14-20, 2009)
(Figure 1). The number of cases reported per sentinel* in Japan was 4.95,
which has increased compared to previous week (3.21 per sentinel). Based
on this number, newly diagnosed ILI patients during this week are estimated
to be approximately 270,000 (95% Confidence Interval 230,000-300,000) nationwide.
According to the School absenteeism surveillance report from Ministry
of Health Labor and Welfare (MoH), in week 37, 166 schools throughout the
nation have been suspended their all classes due to the influenza A (H1N1)
2009 epidemic in school. In addition, one grade was suspended in 500 schools
and 2,840 schools have suspended a individual class with multiple infected
According to Infectious Agents Surveillance Report, most of the influenza cases detected/isolated during the week 19 through 39 were pandemic influenza A(H1N1) virus.
* The number of sentinel clinics
and hospitals is decided depending on the relative population of the
jurisdiction of each public health center and on consideration enabling statistical
estimation of the incidents in the whole area of the prefecture. The influenza
sentinel medical institutions consist of approximately 3,000 pediatric
hospitals/clinics and 1,800 internist hospitals/clinics around the country.
Copyright ©2004 Infectious Disease Surveillance Center All Rights Reserved.