Development of a Reverse Transcription Loop- Mediated Isothermal Amplification [RT-LAMP] as a early rapid detection assay for Crimean Congo Hemorrhagic Fever virus

Presently diagnosis of Crimean Congo Hemorrhagic Fever virus (CCHFV) infection relies on real-time and endpoint RT-PCR, and serodiagnostic assay. These assays are time consuming and cannot be used as a routine screening test. The objective of this study was to develop a rapid diagnostic test that could be completed in < 60 minutes. Rapid detection of CCHFV infection is important for faster delivery of appropriate therapeutics, clinical management of patient and also important to contain the outbreak. In the present study, we have developed a rapid and sensitive single tube reverse transcription loop-mediated isothermal amplification (RTLAMP) assay for detection of CCHFV. The limit of detection of RT-LAMP vis-a-vis Real-time RT-PCR assay is 10 RNA copies. Further, CCHFV specific RT-LAMP assay was successfully evaluated with human and tick samples. The assay correctly picked up diverse CCHFV isolates indicating its applicability for different strains. A comparative evaluation of the RT-LAMP assay vis-`a-vis with the real-time RT-PCR revealed 100% concordance with 100 % sensitivity and specificity respectively. No cross reactivity with related Flaviviruses and hemorrhagic fever viruses was observed. The assay is a rapid, isothermal, simple to perform molecular diagnostic, which can be performed in a portable heating block device. CCHF RT-LAMP assay can be used in low resource laboratories for monitoring of CCHFV outbreaks in remote rural regions in affected countries.