Abstract
Sudden viral outbreaks have increased in the early part of the 21st century, such as those of severe acute respiratory syndrome coronavirus (SARS‑CoV), Middle East respiratory syndrome corona virus, and SARS‑CoV‑2, owing to increased human access to wildlife habitats. Therefore, the likelihood of zoonotic transmission of human‑associated viruses has increased. The emergence of severe acute respiratory syndrome coronavirus 2 in China and its spread worldwide within months have highlighted the need to be ready with advanced diagnostic and antiviral approaches to treat newly emerging diseases with minimal harm to human health. The gold‑standard molecular diagnostic approaches currently used are time‑consuming, require trained personnel and sophisticated equipment, and therefore cannot be used as point‑of‑care devices for widespread monitoring and surveillance. Clustered regularly interspaced short palindromic repeats (CRISPR)‑associated (Cas) systems are widespread and have been reported in bacteria, archaea and bacteriophages. CRISPR‑Cas systems are organized into CRISPR arrays and adjacent Cas proteins. The detection and in‑depth biochemical characterization of class 2 type V and VI CRISPR‑Cas systems and orthologous proteins such as Cas12 and Cas13 have led to the development of CRISPR‑based diagnostic approaches, which have been used to detect viral diseases and distinguish between serotypes and subtypes. CRISPR‑based diagnostic approaches detect human single nucleotide polymorphisms in samples from patients with cancer and are used as antiviral agents to detect and destroy viruses that contain RNA as a genome. CRISPR‑based diagnostic approaches are likely to improve disease detection methods in the 21st century owing to their ease of development, low cost, reduced turnaround time, multiplexing and ease of deployment. The present review discusses the biochemical properties of Cas12 and Cas13 orthologs in viral disease detection and other applications. The present review expands the scope of CRISPR‑based diagnostic approaches to detect diseases and fight viruses as antivirals.