Zoophilic dermatophytes during coronavirus pandemic in Germany

Abstract

During the coronavirus pandemic, significantly more pets were probably bought and kept. This study focuses on whether more zoophilic dermatophytes have subsequently been isolated and which species predominate. In the 1‑year period from March 2020 through February 2021, all zoophilic dermatophytes from all submissions to the Mölbis laboratory were recorded. Both the cultural and the molecular evidence of fungal detection from skin scrapings, hair roots, and, in single cases, from nails, were considered. For dermatophyte DNA (Deoxyribonucleic acid) detection, an in-house polymerase chain reaction (PCR) – enzyme-linked immunosorbent assay (ELISA) was used. In distinct cases, identification of dermatophytes was confirmed by sequencing of the internal transcribed spacer (ITS) region of the rDNA, and of the gene of the translation elongation factor (TEF)-1α. In 579 (2.56%) of 22,575 samples studied in the year 2020/2021, zoophilic dermatophytes were detectable with PCR–ELISA and/or by cultivation. In comparison, the proportion of zoophilic dermatophytes was 2.03% in the 1‑year period 2014/2015, and only 1.6% in 2018/2019. The 579 zoophilic dermatophytes were identified as follows: Trichophyton (T.) benhamiae 186 (32.1%), T. mentagrophytes 173 (29.9%), T. quinckeanum 110 (19.0%), Microsporum (M.) canis 78 (13.5%), T. verrucosum 22 (3.8%), Nannizzia (N.) persicolor 8 (1.4%), T. erinacei 1 (0.2%), and T. equinum 1 (0.2%). T. benhamiae had the highest prevalence from June to September 2020, then again in December. T. quinckeanum is associated with a sharp increase in the mice population in Germany in 2020; a significant increase was found in the months September 2020 to January 2021. T. mentagrophytes had a conspicuous peak in September. Compered with that M. canis in November. Up to 50% of the dermatophytoses caused by T. mentagrophytes, T. quinckeanum, and M. canis affected children and adolescents, while in the case of T. benhamiae it was as much as two thirds. Tinea corporis was the most common, followed by tinea faciei and tinea capitis. M. canis infections affected the capillitium more frequently than the face. Zoophilic dermatophytes were increasingly isolated during the coronavirus pandemic in Germany when compared to previous year periods. In first place, the dermatophyte T. benhamiae from guinea pigs was found in children and adolescents. A significant proportion of dermatophytoses concerned adults. T. quinckeanum is an emerging pathogen in Germany with unprecedented high infection rates in 2020.