Chikungunya in Singapore: Imported Cases Among Travelers Visiting Friends and Relatives: Table 1

Chikungunya infections were detected in Singapore among returning travelers who had visited friends and relatives (VFR) in India and Malaysia. These sporadic imported cases occurred over a year before the 2008 chikungunya outbreaks in Singapore, demonstrating the potential for introducing this emerging viral infection into new areas via VFR travel. Chikungunya infection is an acute viral infection that reemerged in Asia, with ongoing outbreaks in India,1 Indonesia, and Malaysia2 since 2006. Returning travelers with chikungunya infection have been reported in North America3 and Europe, as well as in Hong Kong and Taiwan. However, imported cases of chikungunya infection among travelers visiting friends and relatives (VFR) have not been as extensively documented to date. We report three cases of imported chikungunya in Singapore among VFR travelers and briefly summarize five other cases (Table 1), all of whom presented within a 4‐month period (October 2006–February 2007) and were investigated for evidence of acute or recent chikungunya infection. Cases were considered as proven if confirmed by real‐time reverse transcription‐polymerase chain reaction (RT‐PCR) on serum samples, and probable if serology was positive. These sporadic imported cases occurred a year before the first outbreak of localized transmission, which occurred in Singapore in January 2008.4 Although they did not directly cause the 2008 outbreak in Singapore, these cases represent one potential mean through which chikungunya infection was introduced into Singapore with implications for disease surveillance and outbreak prevention strategies.