Alphavirus Infections ; diagnosis ; epidemiology ; virology ; Animals ; Chikungunya Fever ; Chikungunya virus ; genetics ; isolation & purification ; physiology ; Humans ; Viral Proteins ; genetics ; metabolism

Chikungunya virus ; genetics ; isolation & purification ; China ; Genome, Viral ; RNA, Viral ; genetics ; Sequence Analysis, RNA

PURPOSE: Chikungunya virus (CHIKV) causes endemic or epidemic outbreaks of CHIKV fever, which is a mosquitoe-transmitted viral disease in Africa, India, South-East Asia, and recently Southern Europe. Currently, serological diagnostic tests such as hemagglutination inhibition test (HI test), in-house IgM capture enzyme-linked immunosorbent assays (ELISA), and indirect immunofluorescence test were used for diagnosis of chikungunya fever, which are based on whole virus antigens. MATERIALS AND METHODS: CHIKV E1, and E2 envelope proteins for the CHIKV-specific serodiagnostic reagents for chikungunya fever were expressed in baculovirus expression system. The seroreactivity of recombinant CHIKV E1 and E2 envelope proteins were evaluated using sera panels of patients from Laboratoire Marcel Merieux by indirect IgM capture ELISA. RESULTS: The recombinant CHIKV E1 and E2 envelope protein showed sensitivity of 77.5% and 90%, respectively. The specificities of both CHIKV E1 and E2 envelope proteins were 100%. CONCLUSION: The recombinant CHIKV E1 and E2 envelope proteins could be a useful diagnostic reagent for CHIKV infection.
Alphavirus Infections/*diagnosis ; Animals ; Baculoviridae/genetics/metabolism ; Cells, Cultured ; Chikungunya virus/genetics ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay/methods ; Recombinant Proteins/immunology ; Sensitivity and Specificity ; Serologic Tests/*methods ; Viral Envelope Proteins/*immunology

OBJECTIVETo develop a rapid, cost effective RT-PCR method for the mass scale diagnosis of such diseases at the viremia stage to find out the actual disease burden in that area.

METHODSFor this purpose, cases with the history of only short febrile illness were considered. Thus 157 samples with the history of dengue/chikungunya like illness and only 58 samples with a history of acute encephalitis syndrome (AES) were selected.

RESULTSOut of 157 samples, 42 and 74 were detected as dengue and chikungunya, respectively and out of 58 AES cases only 23 could be detected as Japanese encephalitis by this RT-PCR method.

CONCLUSIONSThis cost effective RT-PCR method can detect the total positive cases that remain undetected by ELISA method. Moreover, this method is capable to detect the viral RNA from patients' sera even after the appearance of IgM antibody at one fifth costs as compared with the other commercially available kits.

Antibodies, Viral ; blood ; Arbovirus Infections ; diagnosis ; virology ; Arboviruses ; genetics ; Chikungunya Fever ; diagnosis ; virology ; Dengue ; diagnosis ; virology ; Encephalitis Virus, Japanese ; genetics ; Encephalitis, Japanese ; diagnosis ; virology ; Fever ; diagnosis ; virology ; Humans ; Immunoglobulin M ; blood ; Mass Screening ; RNA, Viral ; blood ; Reverse Transcriptase Polymerase Chain Reaction ; economics ; methods ; Sensitivity and Specificity ; Viremia ; diagnosis ; virology