Prevalence of clonorchiasis in patients with gastrointestinal disease: A Korean nationwide multicenter survey

Table 1 Distribution of patients according to rivers nearest to the birthplace or place of current residence n (%)

Rivers	Number of patients
Nakdong	947 (31.5)
South Han	774 (25.7)
North Han	270 (9.0)
Geum	303 (10.1)
Yeongsan	137 (4.6)
Seomjin	97 (3.2)
Mangyong-Dongjin	266 (8.8)
Hyeongsan	145 (4.8)
Bulyeong-Wangpi	6 (0.2)
Namdae-Yongok-Osip	64 (2.1)
Not answered	71
Total	3080

Table 2 Frequency and time of raw freshwater fish or snail ingestion among the patients with positive history n (%)

Characteristics	Number of patients
History of ingestion
Present	1140 (37.3)
Frequency
Once	156 (13.9)
2-4 times	318 (28.3)
≥ 5 times	648 (57.8)
Unknown or not answered	18
Time of first ingestion
0-10 yr ago	278 (25.5)
11-20 yr ago	107 (19.0)
21-30 yr ago	179 (16.4)
≥ 30 yr ago	427 (39.1)
Unknown or not answered	49
None	1915 (62.7)
Not answered	25
Total	3080

Table 3 Distribution and infection rate of the patients with positive history of raw freshwater fish or snail ingestion according to river basins nearest to place of residence

River basins	Patients, n (%)	Infected patients (n)	Infection rate (%)
Nakdong	394 (35.2)	132	33.5
South Han	156 (13.9)	12	7.7
North Han	207 (18.5)	15	7.2
Geum	84 (7.5)	7	8.3
Yeongsan	47 (4.2)	19	40.4
Seomjin	65 (5.8)	14	21.5
Mangyong-Dongjin	78 (7.0)	10	1.8
Hyeongsan	54 (4.8)	24	44.4
Bulyeong-Wangpi	3 (0.3)	0	0
Namdae-Yongok-Osip	32 (2.9)	4	12.5
Not answered	20	3
Total	1140	238	20.9

Table 4 Answers to questionnaires regarding knowledge on route of C. sinensis infection

Questions	patients with “Yes”n (%)	Patients with “No”n (%)	Number of notanswered (n)
Did you (the patient him/herself) know that clonorchiasis can be acquired by ingesting raw freshwater fish?	2464 (80.8)	585 (19.2)	31
Did you know that clonorchiasis can also be acquired by eating freshwater shellfish?	1626 (53.3)	1423 (46.7)	31
Did you know that clonorchiasis can be transmitted via kitchen knifes and/or towels?	1441 (47.3)	1608 (52.7)	31
Did you know clonorchiasis can be transmitted by unwashed hands of raw freshwater fish handlers?	1192 (39.1)	1855 (60.9)	33
Did you know that clonorchiasis can be prevented by eating fully cooked freshwater fish?	2371 (77.8)	676 (22.2)	33

Table 5 Sensitivities of various diagnostic modalities for detection of clonorchiasis

Diagnostic modalities	Infected persons, who were tested (n)	Positive results (n)	Sensitivity (%)
Fecal exam for eggs	321	55	17.1
ELISA for circulating antibody	362	157	43.40
Intradermal test	302	225	74.50
Examination of collected bile	134	14	10.40
Radiologic findings	295	34	11.50

Table 6 Distribution of patients with clonorchiasis according to age group n (%)

Age group (yr)	Number of patients (n)	Number of patients with clonorchiasis
0-19	26	0 (0)
20-29	107	7 (6.5)
30-39	222	25 (11.3)
40-49	463	79 (17.1)
50-59	695	99 (14.2)
60-69	831	113 (13.6)
70-79	575	61 (10.6)
≥ 80	161	12 (7.5)
Total	3080	396

Table 7 Presence of clonorchiasis according to history of raw freshwater fish ingestion n (%)

	Number of patients with clonorchiasis
Total number of patients (n = 3080)	396 (12.9)
Patients with positive history of raw freshwater fish ingestion (n = 1140)	238 (20.9)
Patients without raw freshwater fish ingestion (n = 1940)	158 (8.1)

Table 8 Comparison of laboratory findings between patients with clonorchiasis and without clonorchiasis

Laboratory findings	With clonorchiasis (n = 396)		Without clonorchiasis (n = 2684)		P
	Number of patients	mean ± SD	Number of patients	mean ± SD
Eosinophilia1	65	NA	250	NA	0
AST (U/L)	393	104.5 ± 269.56	2671	110.7 ± 263.59	0.665
ALT (U/L)	393	113.5 ± 254.01	2669	107.7 ± 258.17	0.68
Alkaline phosphatase (U/L)	382	304.8 ± 418.35	2611	234.4 ± 350.81	0.002
γ-glutamyl transpeptidase (U/L)	362	200.0 ± 261.19	2233	187.0 ± 440.01	0.585
Total bilirubin (mg/dL)	392	3.07 ± 17.246	2668	3.28 ± 5.401	0.81

¹> 400/mm³ in peripheral blood; NA: Not available.

Table 9 Association between hepatobiliary diseases and presence of clonorchiasis n (%)

Hepatobiliary diseases	Patients with clonorchiasis (n = 396)	Patients without clonorchiasis (n = 2684)	P
Cholangitis	32 (8.0)	242 (9.0)	NS
Bile duct stones	92 (23.2)	716 (26.7)	NS
Gallstone	45 (11.4)	340 (12.7)	NS
Intrahepatic bile duct stones	13 (3.3)	107 (4.0)	NS
Extrahepatic bile duct stones	34 (8.6)	269 (10.0)	NS
Hepatitis	100 (25.3)	650 (24.2)	NS
Hepatitis B virus	58 (14.6)	336 (12.5)	NS
Hepatitis C virus	5 (1.3)	66 (2.5)	NS
Alcoholic	25 (6.3)	159 (5.9)	NS
Toxic	5 (1.3)	40 (1.5)	NS
Autoimmune	1 (0.3)	5 (0.2)	NS
Other causes	6 (1.5)	44 (1.6)	NS
Hepatocellular carcinoma	51 (12.9)	391 (14.6)	NS
Cholangiocarcinoma	34 (8.6)	145 (5.4)	0.015
Gallbladder cancer	9 (2.3)	75 (2.8)	NS
Biliary pancreatitis	6 (1.5)	71 (2.6)	NS

NS: Not significant.

Table 10 Association between prevalence of clonorchiasis and cholangiocarcinoma according to regions of the rivers (n = 560)

	Rivers in southern region1			Rivers in middle region2
	With cholangiocarcinoma	Without cholangiocarcinoma	χ2(P)	With cholangiocarcinoma	Without cholangiocarcinoma	χ2(P)
With clonorchiasis,n(%)	5 (10.4)	43 (89.6)	7.902 (0.005)	19 (10.1)	170 (89.9)	4.2 (0.04)
Without clonorchiasis,n(%)	14 (2.7)	498 (97.3)		20 (5.4)	351 (94.6)
Odd ratio	4.136 (95% CI 1.422-12.030)			1.961 (95% CI 1.020-3.773)
Common odds ratio3	2.289 (95% CI 1.297-4.038)

¹Nakdong, Yeongsan, Seomjin, Hyeongsan Rivers; ²South Han, North Han, Geum, Bulyeong-Wangpi, Namdae-Yeongok-Osip, Mangyong-Dongjin Rivers; ³P= 0.003, result of Cochran’s Mantel-Haenzel test adjusted area.