Abstract 4: Analysis of West Coast Atmospheric Circulation Patterns and Kawasaki Disease “Dry Spells”
Background: Tropospheric winds from northeastern China have been linked to fluctuations in Kawasaki disease (KD) cases in Japan. These winds may carry aerosols that trigger KD in genetically susceptible children. We investigated whether reduced numbers of KD cases were linked to large scale circulation patterns affecting the U.S. West Coast.
Methods: KD cases with either date of onset of fever or date of hospitalization (PHIS, Pediatric Health Information System) were obtained from 5 sites from Seattle to San Diego from 1995-2014. Six days were subtracted from date of hospitalization to approximate date of onset. For each site, periods from December-March were identified for which there were no KD cases for an interval of ≥10 days, called “KD dry spells”. Daily NCEP-NCAR atmospheric Reanalysis 700hPa height anomalies were used to represent the atmospheric circulation.
Results: From 27-48 dry spells were defined for each site. Composites of atmospheric circulation from Day -20 to Day +10 relative to first day of a dry spell were created for each study site. The atmospheric circulation preceding the KD dry spell featured a higher than normal pressure center (results in weakened onshore flow) either offshore over the North Pacific or directly over the site. The circulation anomalies were statistically significant, and unlikely to have occurred by chance. The dry spell pattern intensified and persisted over several days. The strongest anomalous atmospheric circulation (and associated blocked wind flow) occurred between Day -6 to -1 relative to the start of the dry spell. A similar pattern was shared by 4 of the 5 sites. One site featured strong high pressure anomalies > 6 days before the KD dry spells, but only a weak anomaly in the Day -6 to-1 interval preceding the dry spell.
Conclusion: This analysis reinforces results from previous studies of KD case fluctuations in Japan wherein anomalous KD activity was associated with particular wind flow patterns. The circulation patterns associated with the West Coast KD “dry spells” suggest that reduced wind flow from the North Pacific results in reduced KD occurrences. These results support the hypothesis that a KD agent is transported by winds, possibly from a shared source region with transport of the agent across the Pacific.
Author Disclosures: J.C. Burns: None. M. Tyree: None. E.K. Berry: None. X. Rodó: None. D.R. Cayan: None. S.S. Berger: None. M. Bruce: None. J. Daru: None. J.L. Everhart: None. M.J. Gilbert: None. J. Guzman-Cottrill: None. H. Hindo: None. J.S. Kosut: None. G.H. Kurio: None. N.C. Lee: None. C.Y. Mao: None. M.E. Melish: None. D.E. Michalik: None. S. Pathare: None. M. Portman: None. H. Schultz: None. M. Trost: None. S.A. Yee-Guardino: None.
- © 2015 by American Heart Association, Inc.