Two Imported Chikungunya Cases, Taiwan

4. Ong CS, Eisler DL, Alikhani A, Fung VW, Tomblin J, Bowie WR, et al. Novel Cryptosporidium genotypes in sporadic cryptosporidiosis cases: fi rst report of human infections with a cervine genotype. Emerg Infect Dis. 2002;8:263–8. 5. Ong CSL, Isaac-Renton JL. Molecular epidemiological investigations of waterborne cryptosporidiosis outbreaks in Canada. In: Latham SM, Smith HV, Wastling JM, editors. Workshop on the Application of Genetic Fingerprinting for the Monitoring of Cryptosporidium in Humans, Animals and the Environment; Boulder, Colorado, 2003 Aug 3–5. Marlow, Buckinghamshire (UK): Foundation for Water Research; 2004. p. 121–34. 6. Sulaiman IM, Lal AA, Xiao L. A population genetic study of the Cryptosporidium parvum human genotype parasites. J Eukaryot Microbiol. 2001;Suppl:24S– 7S. DOI: 10.1111/j.1550-7408.2001. tb00441.x 7. Trotz-Williams LA, Martin DS, Gatei W, Cama V, Peregrine AS, Martin SW, et al. Genotype and subtype analyses of Cryptosporidium isolates from dairy calves and humans in Ontario. Parasitol Res. 2006;99:346–52. DOI: 10.1007/s00436006-0157-4 8. Ong CSL, Chow S, So PPL, Chen R, Xiao L, Sulaiman I, et al. Identifi cation of two different Cryptosporidium hominis subtypes from cases in the 2001 waterborne cryptosporidiosis outbreak in North Battleford, Saskatchewan. In: Robertson W, Brooks T, editors. Proceedings of the 11th Canadian National Conference and 2nd Policy Forum on Drinking Water; Calgary, Alberta; Apr 2004. Ottawa (Canada): Canadian Water and Wastewater Assoc., Health Canada & Alberta Environment; 2004. p. 628–39. 9. Glaberman S, Moore JE, Lowery CJ, Chalmers RM, Sulaiman I, Elwin K, et al. Three drinking-water–associated cryptosporidiosis outbreaks, Northern Ireland. Emerg Infect Dis. 2002;8:631–3. 10. Zhou L, Singh A, Jiang J, Xiao L. Molecular surveillance of Cryptosporidium spp. in raw wastewater in Milwaukee: implications for understanding outbreak occurrence and transmission dynamics. J Clin Microbiol. 2003;41:5254–7. DOI: 10.1128/JCM.41.11.5254-5257.2003


Two Imported Chikungunya Cases, Taiwan
To the Editor: Chikungunya is a reemerging infectious disease, endemic to Africa and Southeast Asia, caused by a mosquito-borne alphavirus in the family Togaviridae. Numerous chikungunya outbreaks have been reported in Africa and Southeast Asia since chikungunya virus (CHIKV) was fi rst isolated in Tanzania in 1953 (1). Since 2005, several Indian Ocean islands and India have experienced massive CHIKV outbreaks caused by the East/Central/South African genotype (2,3), whereas all earlier isolates from India during 1963-1973 were of the Asian genotype (4). Other chikungunya outbreaks caused by the Asian genotype were frequently reported during 1960-2003 in many Southeast Asian countries, including India, Malaysia, Indonesia, Cambodia, Vietnam, Myanmar, Pakistan, the Philippines, and Thailand. Epidemics caused by reemerging CHIKV were reported in Indonesia and Malaysia during 2005-2007 (1,5).
We have previously reported on fever screening at airports in Taiwan as part of active surveillance for a panel of notifi able infectious diseases such as dengue, gastroenteritis caused by enteric bacteria, malaria, and yellow fever (6). The activity is carried out by using infrared thermal scanners to measure the body temperature of arriving passengers. Diagnostic testing algorithms for patients being screened for fever were based on evaluation by airport clinicians. The rationale behind this process is to minimize local outbreaks by reducing the number of imported cases. We report 2 imported chikungunya casepatients identifi ed in Taiwan by fever screening at airports; 1 had returned from Singapore in 2006, infected with CHIKV East/Central/South African genotype, and the other had returned from Indonesia in 2007, infected with the Asian genotype.
The initial imported chikungunya case was detected at Taiwan Taoyuan International Airport on November, 20, 2006, in a 13-year-old Taiwanese boy who was returning from studying at an international educational training center in Singapore. The second imported case was also detected at Taiwan Taoyuan International Airport on June, 20, 2007, in a 5-year-old boy on his return from visiting relatives in East Kalimantan Province, Indonesia, with his mother. Both case-patients had fever, fatigue, generalized arthralgia, and rash. Real-time RT-PCR screening showed a high level of alphavirus, but not fl avivirus, viremia on day 2 (Singapore imported case) and day 3 (Indonesia imported case) acute-phase samples. Serodiagnosis with immunofl uorescent antibody assay (immunoglobulin M + G + A titers >640), and ELISA showed positive seroconversions for both patients.
Analysis showed that these 2 imported cases were introduced from Singapore and Indonesia and that the patients were infected with CHIKV of East/Central/South African genotype and Asian genotype, respectively. Unlike dengue, chikungunya is not endemic to Singapore. However, a small chikungunya outbreak caused by an Indian strain of East/Central/South African genotype transmitted by Aedes aegypti was reported in January 2008; this occurrence suggests that imported CHIKV may not be detected because of limited transmission and because the signs and symptoms may be mistaken for those of dengue (9). In con-trast, chikungunya has been endemic to Indonesia since 1973. Indonesia had epidemic outbreaks in 1980, 1983-1984, and yearly outbreaks after 1998. In following the ongoing chikungunya epidemic, we have identifi ed 4 additional imported chikungunya cases from Indonesia since July 2007.
A recent chikungunya outbreak in Italy demonstrated that Aedes albopictus is a competent vector that can initiate local transmission of imported CHIKV (10). In Taiwan, Ae. albopictus is distributed throughout the island, and Ae. aegypti is distributed only in southern Taiwan. With increasing numbers of imported CHIKV infections, the risk for local transmission is similar to that of dengue, especially in southern Taiwan. Our results show that CHIKVs of both genotypes are spreading in Southeast Asia. The cocirculation of dengue and chikungunya would likely be increased in many Southeast Asian and African countries because of the rise in international travel and the wide distribution of the competent vectors, Ae. albopictus and Ae. aegypti.