Genetic analysis of chikungunya viruses imported to mainland China in 2008

Abstract

BackgroundChikungunya virus (CHIKV) has caused large outbreaks worldwide in recent years, especially on the islands of the Indian Ocean and India. The virus is transmitted by mosquitoes (Aedes aegypti), which are widespread in China, with an especially high population density in southern China. Analyses of full-length viral sequences revealed the acquisition of a single adaptive mutation providing a selective advantage for the transmission of CHIKV by this species. No outbreaks due to the local transmission of CHIKV have been reported in China, and no cases of importation were detected on mainland China before 2008. We followed the spread of imported CHIKV in southern China and analyzed the genetic character of the detected viruses to evaluate their potential for evolution.ResultsThe importation of CHIKV to mainland China was first detected in 2008. The genomic sequences of four of the imported viruses were identified, and phylogenetic analysis demonstrated that the sequences were clustered in the Indian Ocean group; however, seven amino acid changes were detected in the nonstructural protein-coding region, and five amino acid changes were noted in the structural protein-coding regions. In particular, a novel substitution in E2 was detected (K252Q), which may impact the neurovirulence of CHIKV. The adaptive mutation A226V in E1 was observed in two imported cases of chikungunya disease.ConclusionsLaboratory-confirmed CHIKV infections among travelers visiting China in 2008 were presented, new mutations in the viral nucleic acids and proteins may represent adaptive mutations for human or mosquito hosts.

Epidemiology and control of chikungunya fever in Singapore

“…Malaysia's most recent outbreak occurred from 2008 to 2009, at the same time when cases were exported from Malaysia to China and Japan. 39,40 Singapore, located within close proximity to Malaysia, recorded about 11 million outbound travels to Malaysia (including about 9 million same-day travels) in 2008. 41 Genetic findings in viral isolates confirmed the importation of cases from Malaysia into Singapore.…”

Rapid Identification of Chikungunya and Dengue Virus by a Real-Time Reverse Transcription-Loop-Mediated Isothermal Amplification Method

“…12,26 In China, the first case infected with CHIK virus was reported in 2008. 24 In other countries like India 27 and South East Asia, numerous outbreaks have reemerged. 28 The disease that emerges or reemerges in these countries or areas not only brings an anxiety about the expansion trend of the CHIK, but also causes new social and public health problems.…”

“…The serum samples from the patients and negative controls were tested for the presence of IgM-or IgG-specific antibodies against CHIKV or DENV according to Reference 23. An indirect immunofluorescence test (EUROIMMUN, Lü beck, Germany) was used for CHIK-specific antibody identification, 24 and the Panbio Mac ELISA kit (Australia Panbio company in Melbourne) was used for the detection of DEN. In brief, the samples were diluted 1:10-1:80, and 20 μL were applied to each reaction, and incubated for 1 hour following the manufacturer's instructions.…”

Chikungunya virus with E1-A226V mutation causing two outbreaks in 2010, Guangdong, China

“…With an increase in global travel, the risk that CHIKV will continue to spread to non-endemic regions, such as China, has also increased [22]. Two imported CHIKV cases from Singapore and Indonesia in 2006 and 2007 were reported in Taiwan, China [23], and the importation of five chikungunya fever cases from Sri Lanka and Malaysia to mainland China during March, October, and December of 2008, were reported [24]. …”