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October, 1950 COCCIDIOIDOMYCOSIS 319

group, the lowest percentage of positive reactors in Distribution Map
any of the seven areas in which tests were conducted In the past, the tendency in reporting mycotic
was 16 (probation camp, Azusa) and the highest diseases has often been to indicate the area where
was 30 (Newhall High School). In the other group, an infection was diagnosed or where the sensitivity
the range was from no positive reactors in one of of a patient was observed, without regard to his
the seven areas to 17 per cent in another. past residential history. This may lead to an en-
It is assumed that there is little or no endemic tirely erroneous impression regarding geographical
coccidioidomycosis in the areas in which there was distribution of a disease, since the infection may
low incidence of positive reaction to coccidioidin have been acquired in a region quite remote from
tests. On the other hand, the three areas in which the one where the case was reported. In the accom-
the highest incidence of positive reaction was re- panying map the cases of the disease and the sensi-
corded-the average for the three was 15 per cent tivity causing positive reaction to skin test were
-may be considered as newly recognized endemic verified to have been acquired in the areas marked.
areas. These are the Banning-Palm Springs area in Evidence from these sources, together with re-
which Willett and Weiss22 reported 83 cases of coc- ports of cases in military personnel stationed in the
cidioidomycosis; Camp 4 near Saugus, from which same geographic areas during and since the Second
seven patients with the disease were admitted to the World War, shows that infections may be acquired
Los Angeles County General Hospital in October in the following Southern California counties:
1948;11 and Canoga Park, in the San Fernando Kern, southeast of Tehachapi,18 San Luis Obispo,20
Valley where several patients were suspected to have Santa Barbara,19 Ventura, Los Angeles,1" Orange,
become infected. The average incidence of positive Riverside,*22 San Bernardino,* San Diego,13-'5 and
reactions (15 per cent) in the three newly recog- Imperial.* These data point to a wide distribution
nized areas of endemicity in Southern California of Coccidioides immitis in the southern part of Cali-
compares with an incidence of 68 per cent reported fornia, and the map is not presumed to be complete.
by Gifford8 in similar age groups in Kern County The cases reported to date also indicate that isolated
high schools. pockets or areas of high infection rate may exist
It is of particular interest to compare the low per- interspersed with areas of low endemicity.
centage found in the Los Angeles High School stu-
dents with the higher percentages in the other high Histoplasmin Surveys
school groups. For the entire group of Los Angeles The histoplasmin tests made in this study are
High School students tested, the incidence of posi- summarized in Table 2. Of 984 persons tested, 75
tive reactions was 4 per cent, and it was only 1.6 per (7.6 per cent) had positive reactions. These reactors
cent for those who were not aware of having lived were divided into two groups-those in Group 1
in areas known to be endemic for coccidioidomy- having previously resided in a known histoplasmo-
cosis. The Los Angeles High School is in the center sis area as judged by the map prepared by Smith
of the City of Los Angeles, and the students may be and co-workers,21 and those in Group 2 never hav-
cited as a satisfactory control group, since they have ing resided in an area in which histoplasmosis is
a minimum opportunity for exposure to dust con- known to occur. There was pronounced difference in
taining arthrospores of Coccidioides immitis. Such incidence of reactions between the two groups. In
opportunity would be afforded only by occasional Group 1 the percentage of positive reactors ranged
trips to known endemic areas or by exposure to from 14 per cent in the Los Angeles High School
arthrospores brought to Los Angeles from known group to 45 per cent in Camp 5. In Group 2 there
endemic areas in dust, in cars, clothing or other were few who had positive reaction to histoplasmin,
objects. Reports in the past have shown that coc-
* Endemicity in Areas 13, 21 and 24 (on the map) was
cidioides may be transferred in this manner. reported by the California-Arizona Maneuver Area.

TABLE 1.-Coccidioidin Surveys in Southern California Areas

Total No. Total No. Per Cent Prev. Residence No Residence in
Area Tested Positive Positive in Coccid. Area Known Coccid. Area
Probation Camps: No. Per Cent + No. Per Cent +
No. 4 Saugus. . 100 14 14 31 20 69 12
No. 3 Calabasas .. 78 6 8 25 25 53 0
No. 5 Azusa 60 4 7 27 14 33 3
High Schools:
Banning and Palm Springs 74 15 20 21 21 53 17
Canoga Park .441 65 15 82 24 359 13
Newhall 85 9 11 20 30 65 5
Los Angeles 220 9 4 38 16 182 1.6

1,058 122 11.5
Total ....................