Article in Japanese

Delayed onset of exanthem subitum and a decrease in its morbidity in infants in Japan: Epidemiological changes from 1992 to 2011

Sadayoshi TORIGOE¹⁾, Masahiro WATANABE²⁾, Masao YAMADA³⁾

Epidemiological changes in exanthem subitum (ES) were examined during the 20-year period from 1992 to 2011 in Japan. The onset age, prevalence of infection, and antibodies against human herpesvirus 6 (HHV-6) and -7 (HHV-7) were examined. The mean ages of onset were elevated from 9.3± 4.2 months in 1992-1996 to 13.0± 6.1 months in 2002-2006, and then to 14.6± 7.6 months in 2007-2011; both elevations were statistically significant compared to the prior period (p=0.0001 and 0.03). A decrease in ES morbidity was also suggested. HHV-6 and HHV-7 antibodies were analyzed over two of the periods. The HHV-6 antibody-positive rates in individuals 6 to 11 months of age were 53% in 1992-1996 and 21% in 2007-2011. This decrease was significant (p< 0.05). The delay of HHV-6 infection to children was thought to be the cause of the shift to an older age of onset of ES.

---

1) Aquair Medical Station
2) Suzuka Kodomo Clinic
3) Department of Virology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences

Key words
Received	September 26, 2012
Accepted	December 11, 2012

25 (1)：3─8,2013