An increase in cases if so-called slapped cheek disease since January suggests it is entering a new cycle of infection this year, experts at the National Institute of Infectious Diseases warned Friday.
The disease, officially named erythema infectiosum but also known as fifth disease and "ringo byou" (apple disease), is infectious — especially among children — and usually breaks out every four to six years, peaking in summer. It also poses a hazard to pregnant women.
A tally of about 3,000 designated pediatrics departments found there were 1,596 patients logged in the week ended Feb. 20, bringing the cumulative total since January to 6,413 — the highest since 2007.