A Single-Copy Sensitive and Field-Deployable One-Pot RT-RPA CRISPR/Cas12a Assay for the Specific Visual Detection of...

Nipah virus (NiV) is an emerging bat-borne zoonotic virus that can be transmitted to humans and other animals through infected bats or contaminated foods. The disease is highly lethal in humans (40%-75%) and has the potential for human-to-human transmission. Currently, there are no approved treatments or vaccines for NiV infection in humans or animals. Consequently, there is a pressing need for a highly sensitive, precise, and visually detectable assay to enable early intervention and mitigate the transmission of NiV infection. Here, we report a single-copy sensitive, field-deployable, one-pot visual reverse transcription-recombinase polymerase amplification (RT-RPA)-clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associate system (Cas)12 for the detection of NiV. The assay works by targeting the N gene of NiV, and the results are directly visible to the naked eye. The assay has demonstrated the ability to detect as few as 5.5 copies/μl of positive plasmids or 5.5 × 10¹ copies/μl of RNA transcripts when reacted at constant temperature for 40 min. It showed high specificity for NiV and had no cross-reaction with other pathogens, including rabies virus (RABV), Japanese encephalitis virus (JEV), herpes simplex virus type 1 (HSV-1), Hendra virus (HeV), and Streptococcus suis (S. suis), that can cause clinical symptoms similar to those of NiV infection. Moreover, this assay had a 100% coincidence rate with the reverse transcription quantitative polymerase chain reaction (RT-qPCR) method recommended by the World Organization for Animal Health (WOAH) for the detection of simulated clinical samples, indicating that it has great potential as an ultrasensitive, simple, and portable novel assay for the onsite diagnosis of NiV infection.