title: Utility of IgM ELISA, TaqMan real-time PCR, reverse transcription PCR, and RT-LAMP assay for the diagnosis of Chikungunya fever.
abstract: Chikungunya fever a re-emerging infection with expanding geographical boundaries, can mimic symptoms of other infections like dengue, malaria which makes the definitive diagnosis of the infection important. The present study compares the utility of four laboratory diagnostic methods viz. IgM capture ELISA, an in house reverse transcription PCR for the diagnosis of Chikungunya fever, TaqMan real-time PCR, and a one step reverse transcription-loop mediated isothermal amplification assay (RT-LAMP). Out of the 70 serum samples tested, 29 (41%) were positive for Chikungunya IgM antibody by ELISA and 50 (71%) samples were positive by one of the three molecular assays. CHIKV specific nucleic acid was detected in 33/70 (47%) by reverse transcription PCR, 46/70 (66%) by TaqMan real-time PCR, and 43/70 (62%) by RT-LAMP assay. A majority of the samples (62/70; 89%) were positive by at least one of the four assays used in the study. The molecular assays were more sensitive for diagnosis in the early stages of illness (2-5 days post onset) when antibodies were not detectable. In the later stages of illness, the IgM ELISA is a more sensitive diagnostic test. In conclusion we recommend that the IgM ELISA be used as an initial screening test followed one of the molecular assays in samples that are collected in the early phase of illness and negative for CHIKV IgM antibodies. Such as approach would enable rapid confirmation of the diagnosis and implementation of public health measures especially during outbreaks.
authors.affiliation: Department of Neurovirology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Reddy
authors.forename: Vasanthapuram
authors.initials: V
authors.lastname: Ravi
authors.forename: Anita
authors.initials: A
authors.lastname: Desai
authors.forename: Manmohan
authors.initials: M
authors.lastname: Parida
authors.forename: Ann M
authors.initials: AM
authors.lastname: Powers
authors.forename: Barbara W
authors.initials: BW
authors.lastname: Johnson
mesh_terms: D000328:Adult; D018354:Alphavirus Infections / Q000175:diagnosis*; D065632:Chikungunya Fever; D019411:Clinical Laboratory Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D012680:Sensitivity and Specificity; D014773:Virology / Q000379:methods*