Chikungunya fever in the United States: a fifteen year review of cases.
BACKGROUND
Chikungunya virus (CHIKV) represents a threat to the United States, because humans amplify CHIKV and vectors that transmit CHIKV are present.


METHODS
We described the epidemiology of laboratory-confirmed chikungunya fever (CHIK) cases in the United States in 1995-2009 and compared states with CHIKV vectors with states with returning viremic CHIK cases. For 2006-2009, we evaluated reporting of CHIK cases to ArboNET, the arboviral surveillance system.


RESULTS
In 1995-2009, 109 CHIK cases were identified in the United States; all adult travelers. Sixty-two subjects (57%) had recently visited India, and 13 (12%) had CHIKV viremia. Of the 26 jurisdictions with CHIK cases, 22 (85%) reported the presence of CHIKV vectors. Twelve viremic travelers returned to 6 states with CHIKV vectors. Of the 106 cases identified in 2006-2009, only 27 (25%) were reported to ArboNET, with a median of 122 days (range, 44-273 days) between illness onset and reporting.


CONCLUSIONS
No locally acquired CHIK cases were identified. However, several viremic travelers returned to states with CHIKV vectors and presented a risk for local transmission. Incomplete and delayed reporting made ArboNET less useful. To minimize the risk of CHIKV spread in the United States, healthcare providers and public health officials should be educated about recognition, diagnosis, and reporting of CHIK cases.
Arboviral Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
Katherine B
KB
Gibney
Marc
M
Fischer
Harry E
HE
Prince
Laura D
LD
Kramer
Kirsten
K
St George
Olga L
OL
Kosoy
Janeen J
JJ
Laven
J Erin
JE
Staples
D000328:Adult; D000368:Aged; D018354:Alphavirus Infections / Q000453:epidemiology; D065632:Chikungunya Fever; D002646:Chikungunya virus / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D014195:Travel; D014481:United States / Q000453:epidemiology