Mycoses

MYCOSES, mycosis (from the Greek mykes - mushroom), a collective name for diseases caused by the introduction of parasitic fungi into the organism. Besides humans, many animals (dogs, cats, mice, horses, donkeys, horned cattle, and birds) suffer from M. The most favored location for fungi is the skin [its superficial layer (for example, superficial trichophytosis, favus, and others - keratomycoses) or deep layers (for example, blastomycosis and others)], the skin appendages - hair and nails (see Dermatophytes); internal organs are much more rarely affected by fungi, for example the intestine (M. intestinalis), stomach (in its ulcers), lungs (pneumomycosis), bronchi (bronchomycosis), and others. Additionally, infection of the external auditory canal and eardrum by fungi is known (otomycosis). M. of the skin are very widespread; according to the data from the Breslau dermatological clinic, they constituted about 9% of all skin diseases in Germany. In the USSR this percentage is greater, reaching for example in Odessa almost 25% of all skin diseases, and even more on the outskirts. In the last decade the area of skin mycotic diseases has significantly expanded; cases of dyshidrosis, dyshidrotic eczema, intertriginous lesions, as well as eczema-like and psoriasis-form diseases have been described, in which various fungi are systematically found. The geographical distribution of skin mycoses is very extensive. As an example one can point to the so-called tropical mycoses (tinea imbricata, pinta), which are never encountered outside tropical countries, and to favus, which is never observed in the tropics. The distribution of different forms of the same M. is also uneven. The distribution of some M. of the skin is directly dependent on socio-domestic conditions (see Skin diseases). In the USSR the following M. of the skin are found: trichophytosis (herpes tonsurans, mycosis tonsurans), microsporia, favus, epidermophytosis, pityriasis versicolor, erythrasma, superficial blasto- and oidiomycosis; actinomycosis is less common and other deep M. of the skin (blastomycosis and sporotrichosis) are even rarer. The most common are trichophytosis, favus, and microsporia, which are at the same time the most contagious M.; they are observed predominantly on the outskirts of the USSR. The ratio of trichophytosis, favus, and microsporia to each other for Moscow: 63%, 20%, and 17%; for Leningrad - 52%, 30%, and 18%. The last three M. primarily affect the hairy skin of the head, with rare exceptions, only children get sick. The smooth skin is affected to almost the same extent in adults. The source of infection is a sick person or sick animal (hair, scales, crusts), most often dogs and cats. Epidemics in children's homes, schools, and other places with large concentrations of children are especially dangerous in terms of the spread of these mycoses. In addition, cases of professional M. (for example, infection of the nails in barbers) are encountered. The clinical picture of M. of the skin is very diverse; the diagnosis of many M. of the skin can only be made by laboratory methods (mycological examination, cultures). The precise determination of the mycotic nature of a particular case is important in practical and therapeutic relations. However, it is not always possible to determine the variety of fungus from the clinical picture; for example, mycoses caused by fungi of the Aspergillaceae family (Aspergillus fumigatus, A. Gratioti, A. Fontoynonti, A. Jeanselmi, etc.) do not present anything particularly characteristic clinically. Prevention of M. of the skin consists of a series of sanitary-hygienic measures and improvement of socio-domestic conditions. First place is given to the timely detection, isolation, and treatment of sick children, as well as suspicious cases. When there are many sick children, it is recommended to open special "fungal" schools or classes, since treatment and subsequent control take a long time, during which the child is forbidden to attend school. Constant careful sanitary supervision over schools, kindergartens, playgrounds and houses, nurseries, barber shops, baths, etc., is necessary. A personal preventive measure is the clean maintenance of the skin, since the presence of abundant skin secretions, as well as violation of the integrity of the epidermis, are conditions that favor infection with fungal diseases (for more details - see Actinomycosis, Blastomycetes - blastomycosis, Microsporia, Madura foot, Favus, Sporotrichosis, Trichophytosis).

L. Moshilleyson. Experimental mycoses. Diseases caused by parasitic fungi of the yeast type (blastomycosis, etc.) have not yet been sufficiently studied experimentally. Fungi that affect only the superficial horny layer of the skin (Microsporon furfur, Microsporon minutissimum, etc.) cannot be transmitted to animals under normal conditions. The most thoroughly studied experimentally group of dermatomycoses, which is most common among both humans and animals, is trichophytia, favus, and microsporia. The first experiments on inoculating animals with pathogenic fungi date back to the 1880s. The experiments of Plato and Neisser (1902) with trichophytin greatly increased interest in experimental dermatomycoses; starting from 1908, works by Bruno Bloch and his colleagues appeared, which finally undermined the old view of dermatomycoses as purely local skin lesions; it was proven that the entire organism is often involved in the process; at the same time, some phenomena of immunity and allergy in dermatomycoses were studied. The most susceptible animal to dermatophytes proved to be the guinea pig, to which animal-derived fungi can be transmitted in 100%. Other animals react to the introduction of pathogenic fungi less frequently, and lesions in them are not so characteristic; however, positive inoculations are also obtained in rabbits, white mice and rats, cats, dogs, sheep, horses, cattle, and many others. The best results are obtained with cultures of Aspergillus Quinckeanum, Trichophyton gypseum, and Microsporon lanosum. Among the numerous methods of inoculation, the most widespread is rubbing the material into shaved and scarified skin [see separate table (pp. 47-48), figure 4]. Clinically, a positive result of inoculation is not detected earlier than the 5th-6th day. The process itself proceeds cyclically: up to the 13th-15th day (counting from the moment of inoculation), painful phenomena intensify; later, rapid restitutio ad integrum begins. Scabs together with infected hairs fall off in whole plates, exposing an eroded surface of the skin. Swelling disappears. According to histological studies by Hanawa, a sharp demarcation inflammation with moderate necrobiosis of the superficial layer of the skin forms, bounded below by a ring of degenerated leukocytes. The entire pathologically altered part, together with the fungal elements contained in it, is completely eliminated. By the end of the 3rd or beginning of the 4th week, the entire focus appears covered with normal epithelium, and during the subsequent 2-3 weeks, hair also grows back. Fungi are found either only in the superficial horny layer or also in the upper parts of the follicle and in the hair; hair roots are free of fungi. On re-inoculation, the organism not only does not remain indifferent, but reacts faster and often with more intense inflammation than with primary inoculation. In other words, the organism shows a state of increased sensitivity to the specific agent (allergy). The allergic reaction, acquired after an infection and manifesting upon re-inoculation as more or less sharp inflammation, probably also affects the course of the primary infection. On the one hand, the expression of the allergic state of the skin in humans is secondary eruptions - trichophytids, favids, and microsporids, observed mainly in deeper forms of dermatomycoses, and on the other hand, the body's reaction to the introduction of trichophytin, which has great diagnostic significance. Many authors who used antigen from fungal cultures or trichophytin obtained, especially in deeper forms of trichophytia and microsporia, a complement fixation reaction. With fungi of the genus Monilia, Epstein and Plevako obtained a agglutination reaction in rabbits in a dilution of 1:2,000. With trichophytes, this reaction has not yet been obtained. In guinea pigs infected with gypsum trichophytin, accelerated sedimentation of erythrocytes is obtained. Other questions that have received some clarification through the experimental study of dermatomycoses are the localization of the infectious process and the pathogenesis of secondary eruptions. At present, it can be considered established that a fungus introduced into the body by any route - into the skin, subcutaneously, intravenously, or into internal organs - invariably causes lesions only in the superficial layers of the skin [see separate table (pp. 47-48), figure 5]. The question of why dermatophytes, like sporotricha and blastomycetes, never cause lesions of deeper tissues and organs has long occupied dermatologists. However, only recent experiments (Jadassohn, Sulzberger; 1928-29) have shed light on this extremely interesting problem. It turned out that the conditions for the growth of fungi in the epidermal layer of the skin and in any of the internal organs are equally favorable, provided that the latter are separated from the living organism. For example, it is known that Microsporon Audouini does not infect guinea pigs. However, on 'dead' skin, it is possible to obtain abundant fungal growth. Even more striking are the experiments with extracted organs. If in a guinea pig inoculated with gypsum trichophytin, internal organs (liver, spleen, etc.) are soon removed, then the fungi hematogenously introduced into these organs grow well, while in the control (not removed) organs no growth is observed. Consequently, the fact that pathogenic fungi multiply only in the upper layers of the skin, although they are carried by the blood into internal organs, can be explained by the fact that keratinized tissue as 'dead' provides more favorable growth conditions than living tissue. Another question - about the pathogenesis of secondary eruptions (trichophytids) - received illumination mainly through experiments with hematogenous infection. Individual cases of isolation of fungi from the blood of patients with Trichophytia (Ambrosoli, Jesgner, etc.) remained a mystery until this question was approached experimentally. Fried and Segal were the first in 1929 to use the culture method in hematogenous fungal infection, and the percentage of positive blood cultures in the first hours was 100%; after 28 hours, fungi were isolated from the blood in only 50% of animals, and after 3 days - in only one of eight, which is about 10%. Out of 141 blood cultures taken at various intervals after infection (endogenous), Sulzberger obtained 16 positive ones, which are divided into two phases: early - from 1 hour to 3 days, and late - from 10 to 13 days after infection, i.e., at the acme of inflammation. These data closely lead to the resolution of the problem of the pathogenesis of trichophytids, since it can hardly be doubted that the second late phase of detection of fungi in the blood represents nothing other than spontaneous seeding and coincides with the acme of the inflammatory process, with the maximum of allergy, which is observed in trichophytids.

S. Fried.