ISSN (Print) 0023-4001 ISSN (Online) 1738-0006 BRIEF COMMUNICATION Korean J Parasitol Vol. 52, No. 2: 215-220, April 2014 http://dx.doi.org/10.3347/kjp.2014.52.2.215 Parasitic Infections Based on 320 Clinical Samples Submitted to Hanyang University, Korea (2004-2011) Sung-Chul Choi 1, Soo-Young Lee 2, Hyun-Ouk Song 3, Jae-Sook Ryu 2, Myoung-Hee Ahn 2, * 1 Center for Health Promotion, Samsung Medical Center, Seoul 135-710, Korea; 2 Department of Environmental Biology and Medical Parasitology, Hanyang University College of Medicine, Seoul 133-791, Korea; 3 Department of Parasitology, School of Medicine, Catholic University of Daegu, Daegu 705-718, Korea Abstract: We analyzed 320 clinical samples of parasitic infections submitted to the Department of Environmental Biology and Medical Parasitology, Hanyang University from January 2004 to June 2011. They consisted of 211 nematode infections, 64 trematode or cestode infections, 32 protozoan infections, and 13 infections with arthropods. The nematode infections included 67 cases of trichuriasis, 62 of anisakiasis (Anisakis sp. and Pseudoterranova decipiens), 40 of enterobiasis, and 24 of ascariasis, as well as other infections including strongyloidiasis, thelaziasis, loiasis, and hookworm infecions. Among the cestode or trematode infections, we observed 27 cases of diphyllobothriasis, 14 of sparganosis, 9 of clonorchiasis, and 5 of paragonimiasis together with a few cases of taeniasis saginata, cysticercosis cellulosae, hymenolepiasis, and echinostomiasis. The protozoan infections included 14 cases of malaria, 4 of cryptosporidiosis, and 3 of trichomoniasis, in addition to infections with Entamoeba histolytica, Entamoeba dispar, Entamoeba coli, Endolimax nana, Giardia lamblia, and Toxoplasma gondii. Among the arthropods, we detected 6 cases of Ixodes sp., 5 of Phthirus pubis, 1 of Sarcoptes scabiei, and 1 of fly larva. The results revealed that trichuriasis, anisakiasis, enterobiasis, and diphyllobothriasis were the most frequently found parasitosis among the clinical samples. Key words: Parasitic infection, clinical case, incidence, trichuriasis, anisakiasis Intestinal parasites, for example, Ascaris lumbricoides, hookworms, and Trichuris trichiura were common in Korea until the 1970s. However, these parasites have been steadily decreasing over the last 40 years [1]. In a national survey in 2012, the prevalence of intestinal parasites became 2.6% [2]. In this study, we analyzed not only the intestinal parasites but also extraintestinal parasites detected from clinical specimens submitted to the Department of Environmental Biology and Medical Parasitology, Hanyang University College of Medicine (2004-2011) and compared these results with our previous reports [3]. A total of 782 clinical samples were collected, among which we diagnosed 320 cases of parasitic infections from January 2004 to June 2011. Most of these samples were collected from Hanyang University Hospital and 2 commercial laboratories. Parasite infections were detected by the naked eye and microscopic examinations, examination of stools (formalin-ether Received 3 March 2014, revised 12 March 2014, accepted 15 March 2014. * Corresponding author (mhahn@hanyang.ac.kr) 2014, Korean Society for Parasitology and Tropical Medicine This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. concentration technique), serologic tests (ELISA), blood smears (Giemsa stain), cello-tape anal swab method, and vaginal swab smears. ELISA was carried out for Paragonimus, sparganum, cysticercus (cellulosae), and Toxoplasma. The clinical materials submitted to our laboratory consisted of 164 parasitic adult worms, 63 larvae, 36 stool samples, 24 proglottids, 14 blood smears, 10 sera, 3 vaginal smears, 2 cello-tape slides, and 3 others. We identified 211 cases of nematodes (9 species), 64 trematodes or cestodes (8 species), 32 protozoa (9 species) and 13 arthropods (4 species). Among the nematode infections, there were 67 trichuriasis, 62 anisakiasis, 40 enterobiasis, 24 ascariasis, 7 strongyloidiasis, 9 thelaziasis, 1 loiasis (imported), and 1 hookworm infection. The trematode or cestode infections included 27 diphyllobothriasis, 14 sparganosis, 9 clonorchiasis, 5 paragonimiasis (ELISA), 4 taeniasis saginata, 2 cysticercosis cellulosae (ELISA), 2 hymenolepiasis, and 1 echinostomiasis (Table 1). Among the protozoa, we diagnosed 14 malaria, 4 cryptosporidiosis, 3 trichomoniasis, 3 amoebiasis, 2 Entamoeba dispar, 1 Entamoeba coli, 2 Endolimax nana, 2 Giardia lamblia, and 1 Toxoplasma gondii (ELISA) infections. Among the arthropods, there were 6 cases of Ixodes sp., 5 of Phthirus pubis, 1 of Sarcoptes scabiei, and 1 fly larva (Table 1; Fig. 1). 215
216 Korean J Parasitol Vol. 52, No. 2: 215-220, April 2014 Table 1. Incidence of parasitic infections from 320 clinical samples from 2004 to 2011 Parasite Year 2004 2005 2006 2007 2008 2009 2010 2011 Total (%) Nematoda Trichuris trichiura 4 4 8 8 6 12 16 9 67 (20.9) Anisakis sp. 8 10 7 10 8 3 6 52 (16.2) Pseudoterranova decipiens 2 2 2 1 1 1 1 10 (3.1) Enterobius vermicularis 3 3 6 8 5 5 7 3 40 (12.5) Ascaris lumbricoides 1 4 2 2 4 3 4 4 24 (7.5) Thelazia callipaeda 1 1 4 1 1 1 9 (2.8) Strongyloides stercoralis 1 2 4 7 (2.2) Hookworm 1 1 (0.3) Loa loa 1 1 (0.3) Trematoda Clonorchis sinensis 2 1 1 1 4 9 (2.8) Paragonimus westermani 3 1 1 5 (1.6) Echinostoma hortense 1 1 (0.3) Cestoda Diphyllobothrium latum 2 1 6 1 4 12 1 27 (8.4) Spirometra sp. 2 2 1 3 1 1 4 14 (4.4) Taenia saginata 2 1 1 4 (1.2) Taenia solium (metacestode) 1 1 2 (0.6) Hymenolepis nana 1 1 2 (0.6) Protozoa Plasmodium sp. 1 1 3 3 2 2 2 14 (4.4) Cryptosporidium parvum 1 2 1 4 (1.2) Trichomonas vaginalis 1 1 1 3 (0.9) Entamoeba histolytica 1 1 1 3 (0.9) Entamoeba dispar 1 1 2 (0.6) Entamoeba coli 1 1 (0.3) Endolimax nana 1 1 2 (0.6) Giardia lamblia 1 1 2 (0.6) Toxoplasma gondii 1 1 (0.3) Arthropoda Ixodes sp. 1 1 3 1 6 (1.9) Phthirus pubis 1 3 1 5 (1.6) Sarcoptes scabiei 1 1 (0.3) Phormia regina 1 1 (0.3) Total 35 39 42 44 41 36 54 29 320 (100) T. trichiura and Anisakis were prevalent among individuals in the 40s-50s, Enterobius vemicularis in 0-9 year-old children, A. lumbricoides and sparganum in individuals in the 60s, Diphyllobothrium latum in people in the 40s, and Plasmodium sp. in patients in the 20s (Table 2). The 3 most common parasites were T. trichiura (20.9%), Anisakis and Pseudoterranova (19.3%), and E. vermicularis (12.5%) (Table 1). Among the trematodes and cestodes, the most frequent parasites were D. latum (8.4%), sparganum (4.4%), and Clonorchis sinensis (2.8%). Among the protozoa, Plasmodium sp. (4.4%), Cryptosporidium parvum (1.2%), Trichomonas vaginalis (0.9%), and Entamoeba histolytica (0.9%) were most commonly observed. In our previous report [3] describing 205 clinical specimens obtained from 1986 to 2003, Anisakis or Pseudoterranova spp., E. vermicularis, and Thelazia callipaeda in nematodes, and E. histolytica, T. vaginalis, and Plasmodium sp. in protozoa were most common. Among the arthropodes, Ixodes sp. and P. pubis were predominant [3]. In this study, increased nematode and decreased trematode/cestode samples were collected compared with our previous report (Table 3). According to nationwide surveys performed in Korea in 2004 (3.7% egg positive) and 2012 (2.6% egg positive), the most highly prevalent intestinal parasitic infections were C. sinensis (2.4% and 1.9%, respectively) followed by E. vermicularis (0.6% and not done), Metagonimus yokogawai (0.5% and 0.3%), and T. trichiura (0.3% and 0.4%) [2,4]. In 1986, a total of 188 parasite infections (3.6%) were detected among 5,251 stool samples examined in Hanyang University Hospital. Among them, the most common parasite was C. sinensis (75 cases, 1.4%) followed by T. trichiura (37 cases, 0.7%) and E. coli (40 cases, 0.76%) in Seoul, Korea
Choi et al.: Parasitic infections on 320 samples submitted to Hanyang University 217 A B D E G H 30 μm 10 μm C F 30 μm I 0.5 mm Fig. 1. The parasites from clinical samples between 2004 and 2011. (A, B) Adult worms and eggs of Trichuris trichiura. (C) Anisakis sp. larva. (D) Adult worms of Enterobius vermicularis. (E, F) Strobila and eggs of Diphyllobothrium latum. (G) Plerocercoids (spargana) of Spirometra sp. (H) Plasmodium vivax. (I) Phthirus pubis. [5]. Another study of intestinal parasites over a 10-year period (2003-2012) reported 14,672 cases of parasite infections (among 429,866 people examined, 3.4%). The predominant helminth parasites were C. sinensis (1.2%) and T. trichiura (0.2%), while non-pathogenic protozoan parasites including E. nana (1.6%) and E. coli (0.45%) were also common [6]. Recently, T. trichiura worms are frequently found by colonoscopic examinations [7]. This parasite is a soil-transmitted helminth and its infection occurs via contaminated vegetables or fruits in tropical weather, as a result of poor sanitation, and in areas using human feces as a fertilizer. However, in the present analysis, most of the affected patients had mild Trichuris infections with no symptoms, and the parasite was detected by colonoscopy during health check-up. Anisakiasis is a food-borne parasitic infection, and humans are infected by eating raw or undercooked marine fish or squid [1,8]. This infection is treated by removing the larvae by endoscopy or surgery. Anisakis simplex and Pseudoterranova decipiens are the main species of anisakids reported in Korea. Enterobiasis is common in schoolaged children and in this survey, Enterobius infection was also predominant in children. Humans are the only host that can transfer pinworms, and repeated drug therapy or family treatment is needed [1,8]. D. latum infection is acquired by eating raw or undercooked fish. Fish infected with Diphyllobothrium larvae may be consumed in any country in the world. Lately, Diphyllobothrium infection is increasing in Korea, and importation of foods including fish is an important reason for the spreading of foodborne parasitic infections [9-12]. Most frequent etiologic agents of diphyllobothriasis are D. latum and D. nihonkaiense, however, we did not identify the species of this parasite. Recently, the latter was reported from Japan, Korea, and China. The mitochondrial genome study should be performed for the identification of this tapeworm [13,14]. Sparganosis patients were of-
218 Korean J Parasitol Vol. 52, No. 2: 215-220, April 2014 Table 2. Age and sex distributions of parasitic infections submitted to our Department from 2004 to 2011 Parasite Year/Sex 0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 M F M F M F M F M F M F M F M F M F Unknown Total (%) Trichuris trichiura 1 3 1 7 10 5 12 5 2 1 20 67 (20.9) Anisakis sp. 1 2 8 9 9 8 3 1 1 1 9 52 (16.3) Pseudoterranova decipiens 1 1 2 2 1 3 10 (3.1) Enterobius vermicularis 3 22 1 2 1 1 1 2 1 1 5 40 (12.5) Ascaris lumbricoides 1 1 2 2 2 1 1 2 2 5 5 24 (7.5) Thelazia callipaeda 1 1 1 1 1 1 1 2 9 (2.8) Strongyloides stercoralis 1 1 1 1 1 2 7 (2.2) Hookworm 1 1 (0.3) Loa loa 1 1 (0.3) Clonorchis sinensis 4 3 2 9 (2.8) Paragonimus westermani 1 1 3 5 (1.6) Echinostoma hortense 1 1 (0.3) Diphyllobothrium latum 2 2 2 1 3 3 5 3 2 1 3 27 (8.4) Spirometra sp. 1 1 1 3 3 2 1 1 1 14 (4.4) Taenia saginata 1 2 1 4 (1.2) Taenia solium (metacestode) 1 1 2 (0.6) Hymenolepis nana 2 2 (0.6) Plasmodium sp. 1 4 1 3 1 1 3 14 (4.4) Cryptosporidium parvum 1 2 1 4 (1.2) Trichomonas vaginalis 2 1 3 (0.9) Entamoeba histolytica 1 1 1 3 (0.9) Entamoeba dispar 1 1 2 (0.6) Entamoeba coli 1 1 (0.3) Endolimax nana 1 1 2 (0.6) Giardia lamblia 1 1 2 (0.6) Toxoplasma gondii 1 1 (0.3) Ioxdes sp. 1 1 1 1 2 6 (1.9) Phthirus pubis 1 1 1 1 1 5 (1.6) Sarcoptes scabiei 1 1 (0.3) Phormia regina 1 1 (0.3) Total 6 27 4 5 16 10 24 7 33 27 26 23 19 14 4 5 2 3 65 320 (100) ten encounterd in Korea. The genus Spirometra occurs worldwide, especially in South-east Asia. This parasitic infection is acquired through drinking water containing copepods with procercoid larvae or eating raw or undercooked frogs or snakes. Humans serve as an intermediate or paratenic host for Spirometra spp., and rarely as a definitive host. The most commonly affected site of infection in humans is the subcutaneous tissues, breast, orbit, abdomen, and central nerve system [8]. In this study, the sparganum was removed from the leg, abdomen, breast, thigh, and inguinal regions. Food-borne trematodiasis is a public health problem in Southeast Asia. The habit of eating freshwater fish and trematode infection are closely related. C. sinensis, the liver fluke, is a cause of cholangiocarcinoma or cholangitis; human infections result from eating raw or undercooked freshwater fish of the family Cyprinidae, containing metacercariae. At present, this parasite infection is quite prevalent (1.9% in 2012) in Korea and a well-known endemic area is found near the Nakdong River, in the southeast of the country [1,8,15]. Fish-borne parasites including clonorchiasis, anisakiasis, and diphyllobothriasis showed high prevalences in this study. The first reemergence of vivax malaria in 1993 was reported in a soldier working in the demilitarized zone (DMZ) and the reemergence continued for 20 years during which 1,000-4,000 vivax malaria cases were reported annually [16]. Recently, imported malaria has also increased due to abroad travel, and Plasmodium falciparum is predominant among the imported malaria patients. The national surveillance system of the Korea
Choi et al.: Parasitic infections on 320 samples submitted to Hanyang University 219 Table 3. Comparision of common parasitic infections between present analysis and our previous report Parasite 1986-2003 (Ref. 3) 2004-2011 (present analysis) Nematoda 85 cases (41.5%) 211 cases (65.9%) Anisakis sp./pseudoterranova decipiens (27) a Trichuris trichiura (67) Enterobius vermicularis (15) Anisakis sp./pseudoterranova decipiens (62) Thelazia callipaeda (14) Enterobius vermicularis (40) others (29) others (42) Trematoda & Cestoda 75 cases (36.6%) 64 cases (20.0%) Clonorchis sinensis (21) Diphyllobothrium latum (27) Diphyllobothrium latum (18) Spirometra sp. (14) Spirometra sp. (9) Clonorchis sinensis (9) others (27) others (14) Protozoa 34 cases (16.6%) 32 cases (10.0%) Entamoeba histolytica (12) Plasmodium sp. (14) Trichomonas vaginalis (8) Cryptosporidium parvum (4) Plasmodium sp. (7) Trichomonas vaginalis (3), Entamoeba histolytica (3) others (7) Others (8) Arthropoda 11 cases (5.4%) 13 cases (4.1%) Ixodes sp. (4) Ixodes sp. (6) Phthirus pubis (4) Phthirus pubis (5) others (3) others (2) Total 205 320 a Number of cases. Center for Disease Control and Prevention (KCDC) detected 808 cases of imported malaria between 1994 and 2012 [17]. Our study demonstrates that some obvious parasitic infections including clonorchiasis, trichuriasis, anisakiasis, enterobiasis, and diphyllobothriasis continue to be prevalent in Korea. CONFLICT OF INTEREST We have no competing interest related to this work. REFERENCES 1. Ahn MH. Changing patterns of human parasitic infection in Korea. Hanyang Med Rev 2010; 30: 149-155. 2. Korea Centers for Disease Control and Prevention, National Institute of Health. The 8th National surveys on the prevalence of intestinal parasitic infections. Seoul, Korea. 2013,p 35-68. 3. Song HO, Ahn MH, Choi HK, Ryu JS, Min DY, Ree HI. Analysis of 205 cases of parasitic infection confirmed in clinical specimens. Korean J Clin Microbiol 2004; 7: 66-71. 4. Kim TS, Cho SH, Huh S, Kong Y, Sohn WM, Hwang SS, Chai JY, Lee SH, Park YK, Oh DK, Lee JK. A nationwide survey on the prevalence of intestinal parasitic infections in the Republic of Korea, 2004. Korean J Parasitol 2009; 47: 37-47. 5. Min DY, Ahn MH, Kim KM, Kim CW. Intestinal parasite survey in Seoul by stool examination at Hanyang University Hospital. Korean J Parasitol 1986; 24: 209-212. 6. Kim YE, Huh HJ, Hwang YY, Lee NY. A survey of intestinal parasite infection during a 10-year period (2003-2012). Ann Clin Microbiol 2013; 16: 134-139. 7. Do KR, Cho YS, Kim HK, Hwang BH, Shin EJ, Jeong HB, Kim SS, Chae HS, Cho MG. Intestinal helminthic infections diagnosed by colonoscopy in a regional hospital during 2001-2008. Korean J Parasitol 2010; 48: 75-78. 8. Shin EH, Guk SM, Kim HJ, Lee SH, Chai JY. Trends in parasitic diseases in the Republic of Korea. Trends Parasitol 2008; 24: 143-149. 9. Chai JY. Fish-borne parasitic diseases. Hanyang Med Rev 2010; 30: 223-231. 10. Lee EB, Song JH, Park NS, Kang BK, Lee HS, Han YJ, Kim HJ, Shin EH, Chai JY. A case of Diphyllobothrium latum infection with a brief review of diphyllobothriasis in the Republic of Korea. Korean J Parasitol 2007; 45: 219-223. 11. Keiser J, Utzinger J. Emerging foodborne trematodiasis. Emerging Infect Dis 2005; 11: 1507-1513. 12. Chai JY, Murrell KD, Lymberg AJ. Fish-borne parasitic zoonosis: status and issues. Int J Parasitol 2005; 35: 1233-1254. 13. Arizono N, Yamada M, Nakamura-Uchiyama F, Ohnishi K. Diphyllobothriasis associated with eating raw Pacific salmon. Emerging Inf Dis 2009; 15: 866-870. 14. Park SH, Eom KS, Park MS, Kwon OK, Kim HS, Yoon JH. A case of Dipyllobothrium nihonkaiense infection as confirmed by mitochondrial cox1 gene sequence analysis. Korean J Parasitol 2013; 51: 471-473. 15. Ahn MH, Im KI. Clonorchiasis: clinical cases of Hanyang University Hospital. J Hanyang Coll Med 1985; 5: 347-354.
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