Figure 1Study population flow chart.
Table 1General characteristics of scrub typhus cases between January and December 2009 in Korea
Item |
Male |
Female |
Total |
p∗
|
Age (yr) |
<50 |
415 (24.8) |
453 (16.3) |
868 (19.5) |
<0.001 |
50–59 |
342 (20.4) |
600 (21.6) |
942 (21.1) |
|
60–69 |
431 (25.7) |
741 (26.6) |
1,172 (26.3) |
|
≥70 |
488 (29.1) |
990 (35.6) |
1,478 (33.1) |
|
|
Occupation |
Farmers |
750 (50.4) |
1,232 (47.0) |
1,982 (47.8) |
0.037 |
Non-farmers |
739 (49.6) |
1,390 (53.0) |
2,129 (52.2) |
|
|
Region |
Urban |
Seoul |
49 (3.1) |
58 (2.2) |
107 (2.5) |
|
Busan |
112 (7.0) |
176 (6.6) |
288 (6.8) |
|
Daegu |
36 (2.3) |
65 (2.4) |
101 (2.4) |
|
Inchon |
32 (2.0) |
47 (1.8) |
79 (1.9) |
|
Gwangju |
41 (2.6) |
52 (2.0) |
93 (2.2) |
|
Daejeon |
73 (4.6) |
95 (3.6) |
168 (3.9) |
|
Ulsan |
68 (4.3) |
124 (4.7) |
192 (4.5) |
|
Sub-total |
411 (25.7) |
617 (23.2) |
1,028 (24.2) |
|
|
Rural |
Gangwon |
7 (0.4) |
31 (1.2) |
38 (0.9) |
|
Gyeonggi |
155 (9.7) |
186 (7.0) |
341 (8.0) |
|
Chungbuk |
50 (3.1) |
120 (4.5) |
170 (4.0) |
|
Chungnam |
233 (13.9) |
380 (14.3) |
603 (14.2) |
|
Jeonbuk |
233 (14.6) |
417 (15.7) |
650 (15.3) |
|
Jeonnam |
209 (13.1) |
429 (16.2) |
63 8 (15.0) |
|
Gyeongbuk |
114 (7.1) |
199 (7.5) |
313 (7.4) |
|
Gyeongnam |
192 (12.0) |
268 (10.1) |
460 (10.8) |
|
Jeju |
6 (0.4) |
7 (0.3) |
13 (0.3) |
|
Sub-total |
1,189 (74.3) |
2,037 (76.8) |
3,226 (75.8) |
|
|
Month |
January–September |
131 (7.8) |
192 (6.9) |
323 (7.3) |
0.486 |
October |
907 (54.3) |
1,482 (53.3) |
2,389 (53.7) |
|
November |
600 (35.9) |
1,049 (37.7) |
1,649 (37.0) |
|
December |
33 (2.0) |
58 (2.1) |
91 (2.0) |
|
|
Infection risk factor |
Only fieldwork†
|
673 (46.3) |
1,135 (46.8) |
1,808 (46.6) |
0.706 |
Only outdoor activity‡
|
692 (47.7) |
1,161 (47.9) |
1,853 (47.8) |
|
Both fieldwork and outdoor activity |
87 (6.0) |
130 (5.4) |
217 (5.6) |
|
|
Non-recognized infection risk factor |
Impossible to estimate |
198 (88.4) |
341 (95.0) |
539 (92.5) |
0.003 |
Possible to estimate |
26 (11.6) |
18 (5.0) |
44 (7.5) |
|
|
Major symptoms |
Fever |
1,450 (86.5) |
2,433 (87.4) |
3,883 (87.0) |
— |
Chill |
1,052 (62.8) |
1,739 (62.4) |
2,791 (62.6) |
|
Eschar |
1,254 (74.8) |
2,167 (77.8) |
3,421 (76.7) |
|
Table 2Epidemiological characteristics of scrub typhus cases by region between January and December 2009 in Korea
Item |
Urban*
|
Rural |
Total |
p†
|
Gender |
Male |
411 (40.0) |
1,189 (36.9) |
1,600 (37.6) |
0.072 |
Female |
617 (60.0) |
2,037 (63.1) |
2,654 (62.4) |
|
|
Age (yr) |
<50 |
265 (25.8) |
564 (17.5) |
829 (19.5) |
<0.001 |
50–59 |
259 (25.2) |
620 (19.2) |
879 (20.7) |
|
60–69 |
277 (26.9) |
856 (26.5) |
1,133 (26.6) |
|
≥70 |
227 (22.1) |
1,185 (36.7) |
1,412 (33.2) |
|
|
Occupation |
Farmers |
149 (16.4) |
1,752 (58.1) |
1,901 (48.5) |
<0.001 |
Non-farmers |
757 (83.6) |
1,261 (41.9) |
2,018 (51.5) |
|
|
Month |
January–September |
76 (7.4) |
202 (6.3) |
278 (6.5) |
0.514 |
October |
541 (52.7) |
1,729 (53.7) |
2,270 (53.4) |
|
November |
385 (37.5) |
1,227 (38.1) |
1,612 (38.0) |
|
December |
24 (2.3) |
63 (2.0) |
87 (2.0) |
|
|
Infection risk factor |
Only fieldwork‡
|
125 (14.8) |
1,612 (56.6) |
1,737 (47.0) |
<0.001 |
Only outdoor activity§
|
696 (82.4) |
1,051 (36.9) |
1,747 (47.3) |
|
Both fieldwork and outdoor activity |
24 (2.8) |
184 (6.5) |
208 (5.6) |
|
|
Outdoor activities |
Non-farmers irregularly participate in agricultural activities |
241 (33.5) |
484 (39.2) |
725 (37.1) |
<0.012 |
Climbing and tracking |
135 (18.8) |
199(16.1) |
334 (17.1) |
0.135 |
Gathering chestnuts |
100 (13.9) |
186 (15.1) |
286 (14.6) |
0.479 |
Government-run public work projects∥
|
46 (6.4) |
57 (4.6) |
103 (5.3) |
0.090 |
Mowing around graves |
53 (7.4) |
81 (6.6) |
134 (6.9) |
0.498 |
Others |
188 (26.1) |
298 (24.1) |
486 (24.9) |
0.328 |
Table 3Epidemiological characteristics of scrub typhus cases between January and December 2009 in urban areas
Item |
Seoul |
Busan |
Daegu |
Inchon |
Gwangju |
Daejeon |
Gender |
Male |
49 (45.8) |
112 (38.9) |
36 (35.6) |
32 (40.5) |
73 (43.5) |
41 (44.1) |
Female |
58 (54.2) |
176 (61.1) |
65 (64.4) |
74 (59.5) |
95 (56.5) |
52 (55.9) |
|
Age (yr) |
<50 |
36 (36.6) |
64 (22.2) |
22 (21.8) |
36 (45.6) |
38 (22.6) |
30 (32.3) |
50–59 |
24 (22.4) |
89 (30.9) |
26 (25.7) |
14 (17.7) |
40 (23.8) |
15 (16.1) |
60–69 |
28 (26.2) |
74 (25.7) |
28 (27.7) |
15 (19.0) |
44 (26.2) |
26 (28.0) |
≥70 |
19 (17.8) |
61 (21.2) |
25 (24.8) |
14 (17.7) |
46 (27.4) |
22 (23.7) |
|
Month |
January–September |
9 (7.8) |
18 (6.2) |
15 (14.6) |
13 (15.9) |
7 (4.1) |
10 (9.3) |
October |
81 (69.8) |
126 (43.6) |
58 (56.3) |
40 (48.8) |
105 (61.8) |
67 (62.6) |
November |
26 (22.4) |
137 (47.4) |
29 (28.2) |
26 (31.7) |
55 (32.4) |
26 (24.3) |
December |
0 (0.0) |
8 (2.8) |
1 (1.0) |
3 (3.7) |
3 (1.8) |
4 (3.7) |
|
Infection risk factor |
Only fieldwork∗
|
2 (2.0) |
25 (9.7) |
25 (27.0) |
7 (11.1) |
22 (14.1) |
20 (27.4) |
Only outdoor activity†
|
97 (97.0) |
229 (89.1) |
62 (66.0) |
54 (85.7) |
128 (82.1) |
50 (68.5) |
Both fieldwork and outdoor activity |
1 (1.0) |
3 (1.2) |
7 (7.4) |
2 (3.2) |
6 (3.8) |
3 (4.1) |
|
Outdoor activities |
Non-farmers irregularly participate in agricultural activities |
24 (24.5) |
94 (40.5) |
28 (40.6) |
19 (33.9) |
30 (22.4) |
17 (32.1) |
Climbing and tracking |
19 (19.4) |
44 (19.0) |
12 (17.4) |
5 (8.9) |
30 (22.4) |
10 (18.9) |
Gathering chestnuts |
14 (14.3) |
18 (7.8) |
5 (7.2) |
9 (16.1) |
28 (20.9) |
7 (13.2) |
Government-run public work projects‡
|
1 (1.0) |
33 (14.2) |
1 (1.4) |
1 (1.8) |
6 (4.5) |
0 (0.0) |
Mowing around graves |
17 (17.3) |
10 (4.3) |
1 (1.4) |
9 (16.1) |
8 (6.0) |
6 (11.3) |
Others |
31 (31.6) |
48 (20.7) |
29 (40.6) |
18 (32.1) |
29 (21.6) |
19 (34.0) |