Kawasaki shows a seasonal preference

It seems that far more cases of Kawasaki disease (KD) occur in the winter than at any other time during the year, new research finds.

In the first global study of the seasonality of KD, investigators from California, Spain, Japan, and Australia found that the number of cases of KD in the extra-tropical latitudes of the Northern Hemisphere was highest during the months of January through March.

In fact, the number was 40% higher than in the months with the lowest case numbers, which were August through October. The finding coincides with high and low intensities of tropospheric winds, which experts believe blow the agent causing KD-whatever it is-from the Asian mainland to Japan and across the Pacific to Hawaii and the US mainland.

Led by a scientist at the Kawasaki Disease Research Center at the University of California, San Diego, the global analysis entailed more than 4 decades of research gathered between 1970 and 2012.

Although data were much more sparse in the Southern Hemisphere, they suggested a similar situation, with the number of cases of KD about 30% higher during the months of May through June than during February, March, or October. However, seasonal data from neither the tropics nor the Southern Hemisphere extra-topics reached statistical significance.

The researchers say that their findings support earlier evidence that cases of KD are linked to the large-scale wind currents that travel from Asia to Japan and across the North Pacific.

According to the Centers for Disease Control and Prevention, KD occurs worldwide, but with the highest incidence in Japan. It most often affects boys and younger children. In the continental US, experts estimate an incidence ranging from 9 to 19 per 100,000 children aged younger than 5 years.

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