Comparative study between direct skin smear and polymerase chain reaction test in the identification of human scabies in Al-Kut City, Wasit Province, Iraq

Abstract

This study was performed in order to compare between direct skin smear and polymerase chain reaction (PCR) test in the identificationof human scabies in the City of Al-kut, Wasit Province, Iraq. In accordance with this purpose, 100 skin scrapings were collected from 100 patients, who attended Alkarama Teaching Hospital during the period of January 1 to June 30 of 2021. The samples were subjected to direct smearing using the KOH-traditional method, which was followed by using microscopy to investigate the presence of mites, eggs, and/or egg shells. The samples also were exposed to a PCR test that targeted the mitochondrial cytochrome oxidase subunit 1 (cox1) of mites. The results of the direct smears showed the presence of mites in 8 (8%) of the tested samples. The PCR findings revealed the detection of the cox1 gene in 47 (47%) of the studied samples. PCR revealed 92% and 96% of sensitivity and specificity, respectively, while, the direct smear method showed 14% and 37% of sensitivity and specificity, respectively. The presence work demonstrates higher levels of detection of human scabies by the PCR method than that by the direct skin smears.