Ringworm in Cattle and Endemic Depmatophyte Infections of the Scalp in Man

Abstract

The available data and reports from this country and abroad concerned with ringworm infections are compared in order to determine the part played by cattle ringworm in the endemic spread of dermatophyte infections in man.

The material dealt with in our country being as a rule of a selected type, data therefrom are apt to give an axaggerated picture of the part played by ringworm in cattle in the endemic spread of tinea of the scalp in some areas of the country.

In the course of a systematic campaing against mycotic infections of the scalp in Bosnia, the following species of dermatophytes have been isolated (7.951) cultures performed): a) T. violaceum 4.926 (61, 96%); b) T. schoenleini 2.873 (36, 17%); c) M. audouini 15  (0,19%); d) T. mentagrophytes 78 (0,98%); e) T. verrucosum 43 (0,54%); f) T. tonsurans 11 (0,13%); g) T. quinckeanum 2 (0,02%); h) T. ferrugineum 1 (0,01%).

Systematic examinations are in progress concerned with epidemiologic relation and role of domestic animals in the endemic occurence of dermatophyte infections of the scalp in an area which is by and large livestock rearing.

Of the animals, cattle were assumed in the first place as being the likeliest to provide a source of infection for man owing to the structure of livestock farming, the frequency of infections in cattle and the general clinical appearance of the disease in man as well as the isolated cultures from the lesions.

Our investigations have so far covered ali the farms and villages of Tinja and Srebrenik communes in the district of Tuzla, vvhere 15.117 people (96,5 p.c. of the total population) were examined. In the same area 98,6% of the total number of cattle (4.376) were examied systematically by veterinarians. The results of these examinations are given in six Tables. The striking feature is the large number of households in the two communities (14,4% and 20,6% respectively) vvhere the dermatophyte infection of the scalp was found, and the relatively high percentage of households (3,9% and 5,5% respectively) where only cattle had the infection; in contrast, there were very few household (0,5% and 1,1% respectively) where both tinea capitis and ringworm in cattle was present.

The morbidity rate ranges between 51,2°/00 and 76°/00 in men, and
betwen 24,l°/oo and 59,0°/oo in cattle. A comparison will show that the
infection rate for men does not parallel that for cattle in respective villages.
Two of the Tables give the species of dermatophytes isolated from
material of infected persons and cattle respectively. One of the striking
features is the fact that from the scalp 99,7% of antropophilic species (T. vio-.
laceum and T. schoenleini) were isolated, vvhereas the rest of zoophilic spe­
cies which were isolated from the scalp do not correspond to those isolated
from cattle: T. verrucosum (94,6%) and T. mentagrophytes (5,4%).
The examinations carried out on the field brought out a number of
interesting epidemiological data as regards the extent and transmission of
dermatophyte infections in both man and cattle. Two maps illustrate the
results of a systematic and control examination respectively of people and
cattle of the village Seona, kept under observation 12 months. The first
examination disclosed 55 cases of favus and 37 cases of trichophyton in­
fections of the scalp and 18 cases of ringworm infections in cattle (17 T.
verrucosum and 1 T. mentagrophytes).
A second (control) examination revealed 9 fresh cases of scalp infection
and 7 case of infected cattle. Most of these cases were traced to households
where mycotic infection had been found on the first examination.
After assanation of an infected area fresh cases of the disease in men
with lesions on the sclap as well as ringvvorm in cattle are liable to occur;
these derive as a rule in man from an earlier reservoir of antropophilous
parasites and in cattle from an earlier reservoir of zoophilous fungi.
With reference to persons infected by zoophilic or antropophilic der-
matophytes after puberty, no differentiation could be established in respect
to sex. In both instances the infection of the scalp in grown-ups was on the
whole confined to women, especially in cases of T. violaceum infection.
The results of our investigations clearly show that there is no close
epidemilogical relationship betwen the endemicity of dermatophyte in­
fections of the scalp and the ringvvorm infection in cattle. The various en-
demics of scalp infections by dermatophytes in man follow their natural
course more or less independently and apart from the infection in cattle
vvhich has an epidemiological development of its own.

Human infections, caused by zoophilous dermatophytes in cattle vvhich occur among rural population are as a rule confined to single cases or households only, the disease affecting mainly childron, the lesions appearing usually on the glabrous skin.

The reason why zoophilic dermatophyte infections of the scalp do not occur in man endemically is to be found in biological relation betvveen the parasites and the infected organism. Initial infection with zoophilous species provokes, as a rule, a marked reaction in the organism of man and with further transmission from man to man the pathogenicity of the parasite becomes progressively weaker. Therefore for the zoophilic infection to persist in man and produce an endemic spread of the disease a constant reproduction of fresh infections from animal reservoirs of the parasite would be required — a very remote possibility in view of limited duration of such foci which are dependent upon various ecological influences. 

Consequently, in cases of dermatophyte infections of the scalp by antropophilous species each fresh infection represents at the same time a new focus for susceptible persons whence the disease may spread progressively in endemic form, whereas where zoophilous fungi are concerned the potential powcr of the infection is confincd to a particular reservoir of the parasite which, in most instances, remains attached to the primary focus.