Trigger for KD May Be Wind-Borne

Jane Burns

La Jolla, November 10, 2011 - In an issue of Scientific Reports published on November 10, 2011, Dr. Jane C. Burns, MD, professor and chief, Division of Allergy, Immunology, and Rheumatology at the University of California, San Diego School of Medicine’s Department of Pediatrics and Rady Children’s Hospital-San Diego, suggests large-scale wind currents from Asia to Japan and across the North Pacific may be linked to Kawasaki Disease (KD).

“Our findings suggest an environmental trigger for Kawasaki disease that could be wind-borne,” Burns said. 

Kawasaki Disease (KD) is a severe childhood disease that many parents, even some doctors, mistake for an inconsequential viral infection.  In fact, if not diagnosed or treated in time, it can lead to irreversible heart damage. After 50 years of research, including genetic studies, scientists have been unable to pinpoint the cause of the disease.

Signs of KD include prolonged fever associated with rash, red eyes, mouth, lips and tongue, and swollen hands and feet with peeling skin. The disease causes damage to the coronary arteries in a quarter of untreated children and may lead to serious heart problems in early adulthood. There is no diagnostic test for Kawasaki disease, and current treatment fails to prevent coronary artery damage in at least one in 10 to 20 children and death in one in 1,000 children.   

While seasonality of the disease has been noted in many regions – particularly in Japan, the country of highest incidence for KD – the search for factors that might contribute to epidemics and fluctuations in KD occurrence has been elusive.  A study of KD cases in Japan since 1970 showed three dramatic nationwide epidemics, each lasting several months and peaking in April 1979 (6,700 cases), May 1982 (16,100 cases) and March 1986 (14,700 cases). These three peaks represent the largest KD epidemic events ever recorded in the world.

To investigate a possible influence from large-scale environmental factors, Burns collaborated with Dr. Daniel R. Cayan, Climate Atmospheric Science and Physical Oceanography (CASPO) at Scripps Institution of Oceanography in La Jolla, and Xavier Rodó and Joan Ballester, of the Institut Català de Ciències del Clima and the Institució Catalana de Recerca (IC3) in Barcelona, Spain.

“The linkage to the wind currents, which can cross the Pacific in less than one week, may explain why KD case numbers recorded in Japan, San Diego and Hawaii show a nearly synchronized seasonal peak in disease activity from November through March,” Rodo said. 

Burns reports that the findings could be significant in efforts to isolate the cause of this devastating childhood disease. “It could be that an infectious agent is transported across the ocean by strong air currents developing in the upper troposphere,” she said, adding that while this would seem the most plausible explanation for the findings, the role of pollutants or other inert particles must be considered.

While links between human respiratory disease and large-scale dust transport are well-documented, to date there has been no evidence of long-range wind transport of an infectious agent causing human disease.

Additional contributors to the study include Marian E. Melish, John A. Burns School of Medicine, Kapiolani Medical Center, Honolulu, Hawaii; Yoshikazu Nakamura and Ritei Uehara, Jichi Medical School, Japan.

Funding for the study was provided in part by a grant from the National Heart, Lung and Blood Institute, part of the National Institutes of Health, by the NOAA Regional Integrated Sciences and Assessments program, and by a grant to Rodo from La Marató de TV3 Foundation.

Adapted by Shivani Singh, Sr. Writer, Pediatrics, UC San Diego School of Medicine, Rady Children’s Hospital, San Diego

Original Article by Debra Kain, UC San Diego Media Contact, 619-543-6163 ddkain@ucsd.edu