The Prevalence Of Symptomatic Dermatophytoses In Dogs And Cats And The Pathomechanism Of Dermatophyte Infections

Abstract

Dermatophytoses are skin diseases related to the infection of surface layers of skin and other keratinised structures such as hair and nails, caused by fungi referred to as dermatophytes. The scientific literature provides descriptions of over 50 dermatophytic species classified in the Trichophyton, Epidermophyton, Nannizzia, Arthroderma, Lophophyton, and Paraphyton genera. Dermatophytes are regarded as pathogens; they are not a component of skin microbiota and their occurrence in animals and humans cannot be considered natural. The review of the scientific literature regarding the occurrence and prevalence of dermatomycoses in companion animals revealed significant differences in the prevalence of the infections. Two main factors are most frequently assumed to have the greatest epidemiological importance, i.e. the animal origin and the type of infection. In this aspect, interesting data are provided by investigations of the fungal microbiota present in cat and dog fur. Interestingly, an anthropophilic species Trichophyton rubrum was found to be one of the species of dermatophytes colonising the skin of animals that did not present symptoms of infection. Is the carrier state of this species important in the epidemiology of human infections? Additionally, animal breeders and veterinarians claim that only certain breeds of dogs and cats manifest high sensitivity to dermatophyte infections. The pathomechanism of dermatophyte infections has not yet been fully elucidated; however, three main stages can be distinguished: adhesion of arthrospores to corneocytes, their germination and development of mycelium, and fungal penetration into keratinised tissues. Importantly, the dermatophyte life cycle ends before the appearance of the first symptoms of the infection, which may pose an epidemiological threat. Dermatophyte virulence factors include various exoenzymes, mainly keratinase, protease, lipase, phospho lipase, gelatinase, and DNase as well as toxins causing haemolysis responsible for nutrient supply to pathogens and persistence in the stratum corneum of the host. Clinical symptoms of the infection are external manifestations of the dermatophyte virulence factors.

Major challenges and perspectives in the diagnostics and treatment of dermatophyte infections

“…Additionally, a single species of dermatophytes can cause different types of clinical lesions, that is, tinea corporis, tinea capitis, tinea unguium, etc. Łagowski et al 2019b). Consequently, dermatologists and veterinarians have difficulty in making a diagnosis based only on symptoms of fungal infections.…”

Comparison of in vitro activities of 11 antifungal agents against Trichophyton verrucosum isolates associated with a variety hosts and geographical origin

“…Trichophyton verrucosum is a zoophilic fungus and the most frequent worldwide aetiologic agent of dermatophytosis in cattle and less frequent in other domestic animals and humans. 8,[23][24][25] During the last few years, the number of cases of T. verrucosum isolation from humans suffering from mycoses has been increasing constantly, which is correlated with the presence of cattle rearing farms. 23,24,26 The frequency of T. verrucosum isolation among other dermatophyte species is relatively high in Greece (1.8%), 27 France (1.53%) 24 and Poland (1%).…”

Clinically Used And Potential Antimycotics In The Context Of Therapy Of Dermatomycoses

“…Doniesienia ostatnich lat wskazują, że enzymy te posiadają wysoką specyficzność substratową, która zarazem definiuje spektrum gospodarzy preferowanych przez poszczególne gatunki dermatofitów [28,29]. Jednocześnie uwolnione enzymy pełnią rolę antygenów indukujących i modelujących stan zapalny towarzyszący przede wszystkim infekcjom powodowanym przez gatunki zoofilne [59].…”