RESUMO
BACKGROUND: Japanese encephalitis (JE) is a major public health concern in Asia including India. Objectives: To evaluate an in-house developed dipstick enzyme-linked immunosorbent assay (ELISA) test vis-à-vis two commercial kits for detection of JE virus-specific IgM antibodies. SETTING AND DESIGN: Comparative study carried out in Research and Development centre. MATERIALS AND METHODS: A total of 136 specimens comprising 84 serum and 52 CSF samples were tested by in-house dipstick ELISA, Pan-Bio IgM capture ELISA (Pan-Bio, Australia) and JEV CheX IgM capture ELISA (XCyton, India). RESULTS: The overall agreement among all three tests was found to be 92% with both serum and cerebrospinal fluid (CSF) samples. The sensitivity of the dipstick ELISA was found to be 91% with serum and 89% with CSF samples respectively. The specificity of the dipstick ELISA with reference to both commercial assays was found to be 100% in serum and CSF samples in this study. CONCLUSIONS: The in-house dipstick ELISA with its comparable sensitivity and specificity can be used as a promising test in field conditions since it is simple, rapid and requires no specialized equipment.
RESUMO
BACKGROUND: Dengue, Japanese encephalitis, West Nile encephalitis, yellow fever are the common flaviviral diseases associated with high morbidity and mortality. The initial symptoms of most of the flaviviral infections are similar to each other as well as to some other viral diseases. Making clinical diagnosis, therefore, becomes a challenging task for the clinician. Several studies have been reported on using detection of serum antibodies against flavivirus for the diagnosis of specific flaviviral disease; no field-based pan-flavi virus detection system is available, which can be used in low-endemicity areas for differentiation of flaviviral disease from other viral diseases. AIM: To identify a conserved amino acid sequence among all flaviviruses and evaluate the antibody formed against the conserved peptide to develop pan-flavivirus detection system. MATERIALS AND METHODS: In the present study we have compared amino acid sequences of several flaviviruses and identified a conserved amino acid sequence lying in domain II of envelope protein. RESULTS: A peptide having the conserved amino acid sequence was used to generate polyclonal antibodies and these antibodies were used to detect several flaviviruses. Anti-peptide polyclonal antibodies selectively recognized flaviviruses and did not detect non-flaviviruses. Anti-peptide antibodies detected presence of virus in serum spiked with pure virus preparations. CONCLUSION: The study offers a rationale for development of pan-flavivirus capture assay suitable for low endemic areas.