A nationwide survey was performed to know the distribution and prevalence of human
Gymnophallid trematodes (Digenea: Gymnophallidae) were regarded as parasites commonly found in shore birds but not in humans (
The first human case of
The present study was, therefore, performed in order to determine the distribution and the prevalence of human
Out of a total of 454 islands in the Yellow (western) Sea and South (southern) Sea of the Republic of Korea, 45 (24 western and 21 southern) islands were surveyed (
A total of 4,178 fecal specimens, one specimen per person, were collected through branch offices of the Korea Association of Health, during July-August, 2000. They were transported to the Department of Parasitology, Seoul National University College of Medicine, and stored at 4℃. Formalin-ether sedimentation and Kato-Katz thick smear techniques were applied for examination of the feces. Eggs operculated, elliptical, 0.021-0.025 mm long and 0.011-0.015 mm wide, with thin and transparent shell, were regarded as those of
Of 4,178 fecal specimens examined, 160 (3.8%) appeared positive for eggs of
The egg positive rate of
Among the egg positive cases of
The egg positive rate of
The areas where
The natural definitive host other than man was reported to be the oystercatcher
The present study located 22 coastal islands with
Among the 20 newly found areas of human
The remaining 9 islands were located in the southern sea (Chollanam-do, Kyongsangnam-do, or Pusan-shi), very remote from the known endemic areas. A group of 4 islands (Pyeongildo, Keogumdo, Kogumdo, and Sorokdo), very close to one another, are of considerable interest. The prevalence on these islands was relatively low, and the infection status of oysters around these areas is unknown. However, special attention should be paid on these islands in the future. Still remained 5 islands are scattered, and only a few infected cases were found on each island.
The presence of human infections with
Secondly, if the detected eggs are of
A third possibility is that there may be new definitive hosts other than the oystercatchers and man. This seems to be highly possible, since the host specificity of
The results of the present study clearly indicate that human
The authors are grateful to the members of Kyonggi, Inchon, Chungnam, Chonbuk, Chonnam, Kyongnam, Pusan, and Cheju Branch Offices as well as the Headquarter of the Korea Association of Health for their assistance in collecting fecal specimens.
This study was supported by a grant from
Map showing the areas where the fecal specimens were collected and
Results of fecal examinations for
Province | Name of islands | Area code |
No. exam. | No. egg posit.(%) | mean EPG (min-max) |
---|---|---|---|---|---|
Western coastal islands | |||||
Inchon-shi | Soyado | 1 | 57 | 1 (1.8) | 144 (144) |
Yonghungdo | 2 | 66 | 0 (0.0) | ||
Sonchaedo | 3 | 62 | 0 (0.0) | ||
Kyonggi-do | Chebudo | 4 | 65 | 0 (0.0) | |
Chungchongnam-do | Wonsando | 5 | 94 | 0 (0.0) | |
Sapshido | 6 | 87 | 0 (0.0) | ||
Kodaedo | 7 | 89 | 0 (0.0) | ||
Anmyondo | 8 | 85 | 0 (0.0) | ||
Chollabuk-do | Munyodo | 9 | 98 | 13 (13.3) | 45 (24-72) |
Shinshido | 10 | 93 | 12 (12.9) | 696 (24-4,392) | |
Sonyudo | 11 | 107 | 11 (10.3) | 254 (24-864) | |
Chollanam-do | Amtaedo | 12 | 99 | 25 (25.3) | 111 (24-816) |
Cheungdo | 13 | 92 | 23 (25.0) | 48 (24-144) | |
Anchwado | 14 | 110 | 23 (20.9) | 54 (24-168) | |
Kohado | 15 | 85 | 5 (5.9) | 30 (24-48) | |
Dallido | 16 | 104 | 6 (5.8) | 56 (48-72) | |
Hauido | 17 | 96 | 2 (2.1) | 24 (24) | |
Tochodo | 18 | 95 | 2 (2.1) | 72 (24-120) | |
Hachodo | 19 | 108 | 2 (1.9) | n.e. |
|
Pikeumdo | 20 | 104 | 1 (1.0) | n.e. | |
Nakwoldo | 21 | 93 | 0 (0.0) | ||
Imchado | 22 | 99 | 0 (0.0) | ||
Heuksando | 23 | 90 | 0 (0.0) | ||
Sangchodo | 24 | 103 | 0 (0.0) | ||
Subtotal | 2,181 | 126 (5.8) | 130.4 (24-4,392) | ||
Southern coastal islands | |||||
Chollanam-do | Pyeongildo | 25 | 108 | 10 (9.3) | 240 (72-504) |
Keogumdo | 26 | 113 | 10 (8.8) | 72 (24-120) | |
Kogumdo | 27 | 111 | 6 (5.4) | 288 (96-364) | |
Sorokdo | 28 | 91 | 2 (2.2) | 216 (216) | |
Naenarodo | 29 | 107 | 2 (1.9) | 120 (120) | |
Tolsando | 30 | 93 | 1 (1.1) | n.e. | |
Pogildo | 31 | 103 | 0 (0.0) | ||
Nopdo | 32 | 102 | 0 (0.0) | ||
Nohwado | 33 | 109 | 0 (0.0) | ||
Oenarodo | 34 | 117 | 0 (0.0) | ||
Changdo | 35 | 109 | 0 (0.0) | ||
Sodo | 36 | 100 | 0 (0.0) | ||
Kyongsangnam-do | Sandaldo | 37 | 67 | 1 (1.5) | n.e. |
Kajodo | 38 | 104 | 1 (1.0) | n.e. | |
Yokchido | 39 | 94 | 0 (0.0) | ||
Tumido | 40 | 62 | 0 (0.0) | ||
Yonhwado | 41 | 66 | 0 (0.0) | ||
Pijindo | 42 | 61 | 0 (0.0) | ||
Maemuldo | 43 | 38 | 0 (0.0) | ||
Pusan-shi | Kadokdo | 44 | 128 | 1 (0.8) | n.e. |
Cheju-do | Chuchado | 45 | 115 | 0 (0.0) | |
Subtotal | 1,998 | 34 (1.7) | 184 (24-504) | ||
Total | 4,179 | 160 (3.8) | 154.4 (24-4,392) |
Area code in
n.e.: not examined.
Age and sex prevalence of
Age group | Males |
Females |
Total |
||||||
---|---|---|---|---|---|---|---|---|---|
No. exam. | No. egg positive | (%) | No. exam. | No. egg positive | (%) | No. exam. | No. egg positive | (%) | |
0-9 | 124 | 0 | (0.0) | 123 | 0 | (0.0) | 247 | 0 | (0.0) |
10-19 | 130 | 0 | (0.0) | 106 | 0 | (0.0) | 236 | 0 | (0.0) |
20-29 | 77 | 1 | (1.3) | 85 | 4 | (4.7) | 162 | 5 | (3.1) |
30-39 | 157 | 1 | (0.6) | 226 | 2 | (0.9) | 383 | 3 | (0.8) |
40-49 | 266 | 7 | (2.6) | 296 | 12 | (4.1) | 562 | 19 | (3.4) |
50-59 | 409 | 18 | (4.4) | 486 | 28 | (5.8) | 895 | 46 | (5.1) |
60-69 | 463 | 24 | (5.2) | 575 | 31 | (5.4) | 1,038 | 55 | (5.3) |
70-79 | 193 | 11 | (5.7) | 235 | 10 | (4.3) | 428 | 21 | (4.9) |
over 80 | 38 | 2 | (5.3) | 58 | 2 | (3.4) | 96 | 4 | (4.2) |
unknown | 61 | 3 | (4.9) | 70 | 4 | (5.7) | 131 | 7 | (5.2) |
Total | 1,918 | 67 | (3.5) | 2,260 | 93 | (4.1) | 4,178 | 160 | (3.8) |