Dr. Holló Ferenc szerk.: Parasitologia Hungarica 3. (Budapest, 1970)

satisfactory for interpretation of the PST. The remarks on skin redness also hold true in respect of induration. The pattern of transverse diameters of induration is, however, less regular than that of skin redness. Por this reason, and because interpretation of the PST can be accomplished by measurement of transverse diameter of erythema alone, reading of induration is generally unnecessary. Measurement of induration may, however, provide a basis for evaluation in the absence of notable redness of skin. Results The age distribution of positive skin tests in the three geographical regions is summarized in Table 1 and Pig. 1. The proportion of positive reactors was highest in Budapest, less in county Győr-Sopron, and least in county Veszprém. Owing to the different incidence, specific to age groups, exact data can be obtained only by comparing appropriate age groups. If data of persons between 20 to 60 years old taken into account the prevalence of infection is as follows: county Győr-Sopron: 62,8 $>, Budapest: 57,2 # and county Veszprém: 37,8 These figures indicate some regional disparity of the infection rate. It appears from the results broken down by age groups that infection is most frequently acquired between the ages of 15 and 25 (

Tables 1 and 2, Pig. 1.

). There is a long incidence of infection before puberty. Statistical curves based on figures for decades cover, of course, the considerable scatter apparent if the data are set out annually. The curves show that infection is at a minimum after the age of 30. Sex distribution of the infection was analysed from data of the Budapest sample (

Table 2 and Pig. 2)

.The proportion of infected males was slightly higher than that of females. The difference was, however, significant (x = 8,41; p < 0,05) only in age