Etiology Study of Kawasaki Disease--A Prospective Household and Case Control Study

Patient Selection and Family Surveillance: At National Taiwan University Hospital in Taiwan, we will study patients who fulfill the criteria of Kawasaki disease or atypical Kawasaki disease and their household family members from 2004 to Dec 2005. Institutional Review Board approval will be obtained for this study and informed consents will be obtained from all subjects or their parents. If patients at the emergent service, outpatient clinic or inpatient ward had clinical syndromes suggestive of EV71 infection, they and their household family members were asked to participate in the study. Throat and rectal swabs for virus isolation, and the first blood sample. Clinical manifestations, courses and outcomes were recorded. If at any point the patients suspected of infection displayed clinical symptoms, the other family members in the same household were asked to undergo screening by virus isolation of throat swabs, and received the first blood sample. Questionnaire-based interviews were used to collect information including demographic data, the number of bedrooms in the household, contact time, pattern and presence of current/recent signs and symptoms (cough, rhinorrhea, sore throat, rash, fever, abdominal pain and diarrhea) and preceding contact history with extra-household people who had clinical illness. Follow-up telephone interviews repeated questions about signs and symptoms at 2, 4 and 8-week intervals. If any household family member reported experiencing signs or symptoms suggestive of Kawasaki disease during the follow-up period, the household member will receive further clinical assessment and repeated laboratory investigation for Kawasaki disease. A second blood sample was obtained from the KD cases and all their household family members 4 weeks after the first blood sample was obtained. Control case selection: An age- and sex-matched control will be randomly selected. The control will be the admitted patients in the same ward who have other diagnoses (such as pneumonia, UTI, tonsillitis). They will also receive the screen for virus and bacterial workup as the household members do.

Definitions of Kawasaki disease and atypical Kawasaki disease:

1. Criteria for Kawasaki disease:

• equal to or over five of the following: fever for more than 5 days, non-purulent conjunctivitis, skin rash, palm/sole induration and erythema followed by desquamation, neck lymphadenopathy, strawberry tongue or lip fissure/bleeding

2. Atypical Kawasaki disease; less than five of the above but with coronary artery aneurysm.

Laboratory Methods