Species with Doubtful Ecology and Often Referred to As Zoophilic
Insufficient data are available on distribution of T. eriotrephon which is known from four cases of dermatophytosis in man (tinea corporis, Netherlands; tinea manuum and tinea faciei, Iran; tinea barbae, France) (Papegaay 1925; Rezaei-Matehkolaei et al.
2013; Sabou et al. 2018) and a dog (isolate IHEM 24340 from Belgium). Two isolates of unnamed species usually called “African race of Arthroderma benhamiae” are known from dermatomycosis in man (Takashio 1974). It is anticipated that both species are zoophilic based on clinical manifestation of infection and their close phylogenetic relationships to pathogenic Trichophyton species (Fig. 3.3).Occasionally, cases of infections in various animals and human are attributed to species from geophilic Nannizzia (formerly Microsporum) species (N. gypsea, N. fulva, N. persicolor, N. praecox, N. incurvata, N. nana, etc.). Some of these species (mainly N. persicolor and N. nana) are commonly designated as zoophilic in the medical literature solely based on the evidence of previous clinical cases. Indeed, the boundaries between zoophilic and geophilic species are not always sharp, and this is usually due to insufficient ecological data. Epidemiological features typical for geophilic species involve low host specificity (infections are reported from broad range of animals), clinical cases occur separately without clear connection between themselves (except of contact with soil), geographic origin of clinical isolates do not correlates with distribution of any host, and the dermatophyte species have very limited potential to cause significant outbreaks even if they occur in animals kept in large numbers in a limited space (low contagiousness). Geophilic species N. persicolor, relatively commonly associated with infections in dogs (Carlotti and Bensignor 1999; Muller et al. 2011) and humans (Chen et al.
2012; Hubka et al. 2014b) but frequently misidentified with T. mentagrophytes, can serve as a good example. The species was considered to be zoophilic in the past with probable reservoir in rodents (Kane et al. 1987). Its geophilic nature was confirmed by subsequent investigations of soil samples that revealed widespread dispersal of N. persicolor in soil (Sharma et al. 2008). In addition, poor growth at 37 °C and significant intraspecies variability revealed by using molecular data are typical for geophilic species rather than primarily pathogenic ones (Sharma et al. 2008). Phylogenetic position of N. persicolor within geophilic species from N. gypsea complex is in agreement with such conclusion because related dermatophytes have usually similar ecology (Graser et al. 2008).Similar doubts on ecology exist in Trichophyton simii and Lophophyton (=Microsporum) gallinae which were traditionally considered zoophilic species with reservoir in monkeys or chickens, respectively. Both species fulfill many criteria typical for geophiles listed above. Trichophyton simii is known from sporadic cases of animal and human mycoses without specific predilection sites. The majority of case reports were summarized by Beguin et al. (2013), and they were described worldwide and involved monkeys, poultry, man, and dog (Okoshi et al. 1966; Clayton 1978; Constantino and Torre Mendoza 1979; Beguin et al. 2013; Yamaguchi et al. 2014). The species is known from soil or sand in India (Padhye and Thirumalachar 1967; Gugnani et al. 1968; Padhye and Carmichael 1968; Jain and Sharma 2011), France (Visset 1973), and Ivory Coast (Beguin et al. 2013) and was also recovered abundantly from asymptomatic small mammals in India, Africa, and Czech Republic (Gugnani et al. 1968, 1975; Ditrich and Otcenasek 1982; Hubalek 2000), from the fur of baboon in Guinea (Mariat and Tapia 1966) and poultry feather (Hubalek 2000) bringing another evidence of probable geophilic origin. No outbreaks were reported except of local epizootic in poultry (Gugnani and Randhawa 1973).
Lophophyton gallinae is well known as a causative agent of avian dermatophytosis (favus) that predominantly manifests in chicks and roosters as white to yellow scales or thick crusts on the comb and wattle; hens are less commonly affected. In severe cases, the infection spread on the other parts of the face, head, and neck with feather loss. The majority of infections was summarized previously by Murata et al. (2013) and older reports by Londero et al. (1969). These cases are again distributed worldwide and involved chickens but also ducks, dogs, monkeys, cats, squirrels, mouse, canary, pigeon, turkey, and man (no apparent predilection site in humans); outbreaks were rarely reported (Londero et al. 1969; Bradley et al. 1993). It is worth noting that some animals were healthy without any signs of infection, and no contact with birds was revealed in history of some patients. The fungus is known also from birds' nests of blue tit (Cyanistes caeruleus) and great tit (Parus major) (Goodenough and Stallwood 2010). Kawasaki et al. (1995) revealed close relationships between M. gallinae, geophilic M. Vanbreuseghemii, and its sexual state Arthroderma grubyi. The conspecificity of these was subsequently supported by analysis of ITS rDNA region (Graser et al. 1999a, 2008; de Hoog et al. 2017). The synonymization of these taxa was surprising due to different morphology and mating behavior. The ecology of former M. vanbreuseghemii is ambiguous (soil, asymptomatic as well as symptomatic animals and humans), similar to L. gallinae.
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