1 www.eurosurveillance.org Rapid communications Chikungunya fever in two German tourists returning from the Maldives, September, 2009 M Pfefer (pfefer@vetmed.uni-leipzig.de) 1 , I Hanus 2 , T Löscher 2 , T Homeier 1 , G Dobler 3 1. Institute of Animal Hygiene and Veterinary Public Health, Veterinary Faculty, University of Leipzig, Germany 2. Department of Infectious Diseases and Tropical Medicine, University of Munich, Munich, Germany 3. Bundeswehr Institute of Microbiology, Munich, Germany Citation style for this article: Citation style for this article: Pfefer M, Hanus I, Löscher T, Homeier T, Dobler G. Chikungunya fever in two German tourists returning from the Maldives, September, 2009. Euro Surveill. 2010;15(13):pii=19531. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19531 This article has been published on 1 April 2010 This report describes the first isolation and molecu- lar characterisation of a chikungunya virus from two German tourists who became ill after a visit to the Maldives in September 2009. The virus con- tained the E1 A226V mutation, shown to be respon- sible for an adaptation to the Asian tiger mosquito Aedes albopictus. The E1 coding sequence was identi- cal to chikungunya virus isolates from Sri Lanka and showed three nt-mismatches to the only available E1 nt sequence from the Maldives. Introduction Since the start of the current chikungunya fever pan- demic on the east coast of Africa in 2005, many cases have been reported in countries in Asia and south-east Asia [1,2]. These cases were attributed to a particular chikungunya virus (CHIKV) strain that has adapted to very efficient transmission to humans via the Asian tiger mosquito ( Aedes albopictius) due to a A226V mutation in the E1 envelope protein [3,4]. The Maldives were first hit by the chikungunya virus pandemic in late 2006 after the wet season which usually lasts until September. Based on almost 12,000 suspected cases of chikungunya fever the disease was reported on 121 of the 197 inhabited islands with incidence rates between 82 and 722 per 1,000 population [5]. A small set of blood samples from febrile patients with symp- toms meeting the chikungunya fever case definition at that time confirmed CHIKV as causative agent in 64 of 67 cases by reverse-transcription PCR (RT-PCR) [5]. However, no further characterisation of the virus strain responsible for the 2006-7 outbreak was per- formed. One case of a traveller returning to Singapore in January 2007 was confirmed by RT-PCR and the nt sequence of the E1 gene was determined [6]. In early 2009, an outbreak of a viral fever with symptoms including myalgia or arthralgia and rash occurred on several islands of the Laamu Atoll about 400 km south of Malé [7], but no further virological investigation was carried out to determine whether this was due to den- gue or chikungunya fever. Case report and laboratory findings Between 1 and 10 September 2009, a German couple visited the Dhiffushi Holiday Island resort at the south- ern tip of the Ari Atoll, the Maldives (Figure 1), together with their seven year-old son. They flew directly from Munich to Malé with a stopover in Dubai, United Arab Emirates. Two and three days respectively after the family had returned to Munich, the son and the 35 year-old father developed symptoms compatible with either dengue or chikungunya fever (Table) while the wife stayed healthy. A test for dengue virus showed neither virus RNA nor anti-dengue virus (DENV) IgM for both patients, but the father had IgG antibodies reactive against DENV indicating an earlier anamnestic den- gue fever or a cross-reaction with an earlier flavivirus vaccination. CHIKV-specific real-time RT-PCR yielded ct-values of 23 (son) and 22.5 (father) in the respec- tive acute serum samples obtained on 14 September, indicating high-level viremia [8,9]. Chikungunya virus was isolated in Vero B4 cells from both sera and the entire nucleotide sequence of the isolate from the father was determined. The viral genome was 11,811 nucleotides in length and showed high levels of iden- tity with the pandemic CHIKV that is circulating in many parts of the Indian subcontinent and other parts of Asia since 2006. Most interestingly the CHIKV iso- late from the Maldives contained the A226V change in the E1 glycoprotein which has been shown to be responsible for shorter extrinsic incubation periods in Aedes albopictus mosquitoes [4]. While the son made an uneventful recovery after one week of symptoms, the father developed persisting arthralgias with limited mobility in the affected extremities and still requires analgesic treatment (Table). Discussion Together with a very recent report on chikungunya fever in a French traveller returning from the northern part of Malé Island, Maldives, in October 2009 [10], our findings suggest a continuous circulation of CHIKV also in other parts of the Maldives. The family stayed