A LAMP-based assay for rapid detection of human scabies using clinical skin scraping specimens

Scabies, a common parasitic skin disease caused by Sarcoptes scabiei var. hominis, presents diagnostic challenges because of its diverse clinical manifestations and the limited sensitivity of traditional methods, such as skin scraping. Here, we developed a loop-mediated isothermal amplification (LAMP) assay targeting two S. scabiei-specific genes, Sarcoptes scabiei allergen Sar s 3 (Sars3) and Internal Transcribed Spacer 2 (ITS2). To enhance operational simplicity, a direct lysis protocol was employed, enabling rapid template DNA acquisition from skin scraping specimens without conventional DNA extraction. Primer sets were optimized for amplification speed and specificity; reaction temperatures were determined to be 67 °C for Sars3 and 61 °C for ITS2. The assay achieved detection within 35 min, with limits of detection of 10³ copies for Sars3 and 10² copies for ITS2. No false-positive signals were observed across the 144 negative control reactions for each target. The assay demonstrated high specificity for non-target DNA from humans and house dust mites. Clinical validation using skin scrapings from patients with classic and crusted scabies yielded consistently positive results, whereas samples from non-scabies controls yielded negative results. These findings indicate that the developed LAMP assay provides a diagnostic platform for scabies, requiring minimal and portable equipment, making it suitable for clinical or point-of-care settings.