� 174 CMYK www.jpgmonline.com Original Article Fusogenic peptide as diagnostic marker for detection of Fusogenic peptide as diagnostic marker for detection of Fusogenic peptide as diagnostic marker for detection of Fusogenic peptide as diagnostic marker for detection of Fusogenic peptide as diagnostic marker for detection of flaviviruses flaviviruses flaviviruses flaviviruses flaviviruses Virology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior - 474 002, MP, India Correspondence: Priyabrata Pattnaik, E-mail: p.pat@rediffmail.com Received : 20-09-05 Review completed : 31-03-06 Accepted : 09-05-06 PubMed ID : 16855316 J Postgrad Med 2006;52:174-8 Pattnaik P, Srivastava A, Abhyankar A, Dash PK, Parida MM, Lakshmana Rao PV ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT 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. KEY WORDS: Flavivirus,detection,fusionpeptide,dot-ELISA,viruscaptureassay,pan-flavi T he last decade witnessed emergence and re-emergence of several microbial infections. A majority of them have been vector-borne infections [1] especially, the arthropod-borne viral diseases, which constitute 90% of the re-emerging diseases. The early manifestations of most of diseases caused by the flaviviruses are very similar to those caused by other viral fevers. From the epidemiological as well as therapeutic point of view, it is essential to differentiate flaviviral infection from other viral infections using a validated laboratory diagnostic method. Several diagnostic systems are available for the detection of circulating antibodies in patient serum. [2,3] However, no gold standard is available for immunological diagnosis of flaviviruses. Though PCR based diagnosis has become very common, it cannot be used in field conditions and requires trained manpower. A field based simple method to use pan-flavi virus detection system will be of great help specifically for low endemic areas to differentiate flavivirus infections from other viral infections. In the present report we describe an approach for early diagnosis of flaviviral diseases by detecting presence of the viruses using antibody against a peptide corresponding to conserved fusogenic motif of flaviviruses. Materials and Methods Identification of flavi-specific epitope Amino acid sequences of envelope protein of several flaviviruses were downloaded from NCBI databank. Amino acid sequences of Dengue virus type 1 (NCBI accession no. AY153755), Dengue virus type 2 (NCBI accsesion no. M29095), Dengue virus type 3 (NCBI accsesion no. AY099342), Dengue virus type 4 (NCBI accsesion no. AF326573), Japanese encephalitis virus (NCBI accsesion no. NP775666), yellow fever virus (NCBI accession no. NP740305), West Nile virus (NCBI accession no. AAR17573), tick borne encephalitis virus (NCBI accession no. AAC62100), Kyasanur Forest disease virus (NCBI accession no. CAA52211) and Omsk hemorrhagic fever virus (NCBI accession no. NC005062) were considered for evaluation of flavi-specific epitope and identifying conserved amino acid sequences. Amino acid sequences were edited and analyzed by the Lasergene software package V5.0 (DNASTAR Inc, USA). Multiple sequence alignments were carried out employing � 174 J Postgrad Med September 2006 Vol 52 Issue 3