• Parasites, Hosts and Diseases
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• v.54 no.2
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• pp.215-219
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• 2016

Clonorchis sinensis is currently the most important parasite affecting public health problems in the Republic of Korea. We investigated the prevalence of C. sinensis infection among residents living along 5 major rivers in Korea. A total of 42,562 individual stool samples were collected from 37 localities and examined using the formalin-ether sedimentation technique. Helminth eggs were detected in 4,052 (9.5%) residents and 3,586 (8.4%) were infected with C. sinensis. The egg positive rate of C. sinensis in Nakdong, Seomjin, Geum, Yeongsan, and Han River was 11.7%, 9.9%, 6.5%, 3.1%, and 1.0%, respectively. The overall prevalence of clonorchiasis by sex was 11.2% in males and 6.2% in females. The age-prevalence was the highest in the 50-59 years band. It has been reconfirmed that the endemicity of clonorchiasis is higher in southern areas of Korea, especially along Nakdong and Seomjin Rivers. A combination of continuous control programs with health education initiatives is urgently required in these highly endemic areas of clonorchiasis in Korea.

• Parasites, Hosts and Diseases
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• v.45 no.1 s.141
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• pp.33-38
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• 2007

To know the prevalence of heterophyid trematodes among inhabitants of a southern coastal village, i.e., Sacho-ri, Gangjin-gun, Jeollanam-do(Province), 82 stool samples were examined on helminth eggs and protozoan cysts using Kato-Katz and formalin-ether sedimentation techniques. Total 33 people(40.2%) were positive for trematodes(Heterophyes nocens; 15 people, Pygidiopsis summa; 3, Metagonimus sp.; 4, Clonorchis sinensis; 7, Gymnophalloides seoi; 6) and/or protozoa(Entamoeba coli; 3). Among intestinal trematode egg positive cases, 17 were treated with praziquantel and their whole diarrheic stools were collected after purgation. Adult flukes of H. nocens(number of specimens=1,294), P. summa(386), Stellantchasmus falcatus(5), Stictodora lari(4), and Heterophyopsis continua(1) were collected using a stereomicroscope. To know the source of human H. nocens infections in this village, metacercarial infections in mullets(10) were examined and most H. nocens metacercariae(101/105, 96.2%) were found in the trunk portion. From above results, the surveyed coastal village has been newly known as an endemic focus of human H. nocens infection and consuming raw mullets was the presumable source of human heterophyid infections.

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.197-201
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• 2017

Shahr-e Sukhteh (meaning burnt city in Persian) in Iran is an archeological site dated back to around 3,200-1,800 BC. It is located in Sistan and Baluchistan Province of Iran and known as the junction of Bronze Age trade routes crossing the Iranian plateau. It was appointed as current study area for paleoparasitological investigations. Excavations at this site have revealed various archeological materials since 1967. In the present study, sheep and carnivore coprolites excavated from this site were analyzed by means of rehydration technique using TSP solution for finding helminth eggs. Dicrocoelium dendriticum, Capillaria sp., and Taenia sp. eggs were identified, while some other objects similar to Anoplocephalidae and Toxocara spp. eggs were also retrieved from the samples but their measured parameters did not match those of these species. The present paper illustrates the first paleoparasitological findings of Bronze Age in eastern Iran supporting the economic activities, peopling, and communication as well as the appropriate condition for zoonotic helminthiasis life cycle in Shahr-e Sukhteh archeological site.

• Journal of agricultural medicine and community health
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• v.15 no.2
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• pp.107-111
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• 1990

A survey was undertaken to evaluate the present status of intestinal infection in army soldiers. Stool specimen of 417 soldiers fixed by SAF solution were collected from a camp located in area of Nakdong river during the period from August to October of 1990. And these stool samples were examined by formalin-ether sedimentation technique once for helminths and protozoan cysts stained with Lugol's iodine solution. The results obtained in this survey were summarized as follows : l) The overall positive rate of intestinal parasite was 18.0%. 2) The egg positive rate of intestinal helminth was 15.1%, : and 11.5% for Clonorchis sinensis. 5.0% for Metagonimus vokogawai, 1.2% for Ascaris lumbricoides 1.7% for Trichiuris trichiura. 0.2% for Taenia sp. 3) The cyst positive rate of intestinal protozoa was 4.1% ; and 1.4% for Entamoeba coli, 1.9% for Giardia lamblia 0.7% for Entamoeba histolytica, 0.5% for Endolimax nana. 4) Most of samples were positive(85.3%) by single species. 10.7% by two species, 2.7% by three species and 1.3% by four species. 5) Infection rate of intestinal parasites among army soldiers decreased distinctly compared with previous data but it is revealed that the infection rate of Clonorchis sinensis among army soldiers in area of Nakdong river is still high in comparison with ever-reported data. 6) SAF fixatives used in this field survey during summertime was useful to conserve protozoan cyst and helminths ova. Also we could examine stool samples directly by formalin-ether sedimentation technique.

• Parasites, Hosts and Diseases
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• v.54 no.5
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• pp.555-563
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• 2016

For several years, we have conducted a series of studies on the patterns of ancient parasitism prevailing in the soil of rural and urban areas of past Kingdom of Korea. Actually, during our survey of paleoparasitology in archaeological sites of Korean peninsula, numerous ancient parasite eggs were discovered in the samples from the city districts of Hansung (Joseon) and Buyeo (Baikje), the palace moat at Gyeongju (Silla), shell-midden site at Bonghwang-dong (Silla to Joseon), and the reservoir found in Hwawangsansung fortress (Silla). By the paleoparasitological studies, with respect to parasitism in the high-density populations of ancient towns and cities, we have managed to catch glimpses of the patterns prevalent therein: a serious parasitic contamination of the soil in ancient urban areas, but not in rural areas of the past. Our historical research also proposed the plausible mechanism of parasite infection very serious indeed among urban populations in Korean history. Although city dwelling doubtless has accrued significant benefits for people and populations with agriculture, it can be equally supposed that living in such highly populated areas might have facilitated the spread of parasite infection.

• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.135-144
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• 2019

There have been some reports on schistosomiasis of school children in Sudan's Nile River basin area; however, information about the infection status of Schistosoma species and intestinal helminths among village residents of this area is very limited. Urine and stool samples were collected from the 1,138 residents of the Al Hidaib and Khour Ajwal villages of White Nile State, Sudan in 2014. The prevalence of overall schistosomiasis and intestinal helminthiasis was 36.3% and 7.7%, respectively. Egg positive rates were 35.6% for Schistosoma haematobium, 2.6% for S. mansoni, and 1.4% were mixed. The prevalence of schistosomiasis was significantly higher in men (45.6%) than in women (32.0%), in Khou Ajwal villagers (39.4%) than in Al Hidaib villagers (19.2%), and for age groups ${\leq}15$ years old (51.5%) than for age groups >15 years old (13.2%). The average number of eggs per 10 ml urine (EP10) of S. haematobium infections was 18.9, with 22.2 eggs in men vs 17.0 in women and 20.4 in Khou Ajwal villagers vs 8.1 in Al Hidaib villagers. In addition to S. mansoni eggs, 4 different species of intestinal helminths were found in the stool, including Hymenolepis nana (6.6%) and H. diminuta (1.0%). Collectively, urinary schistosomiasis is still prevalent among village residents in Sudan's White Nile River basin and was especially high in men, children ${\leq}15$ years, and in the village without a clean water system. H. nana was the most frequently detected intestinal helminths in the 2 villages.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.239-242
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• 2012

The influence of temperature on the development and embryonation of Ascaris suum eggs was studied using coarse sand medium in an environmental chamber with 50% humidity. The time required for development and embryonation of eggs was examined under 3 different temperature conditions, $5^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$. A. suum eggs did not develop over 1 month at the temperature of $5^{\circ}C$. However, other temperature conditions, $25^{\circ}C$ and $35^{\circ}C$, induced egg development to the 8-cell-stage at days 5-6 after incubation. All eggs examined developed to the 8-cell stage at day 6 after incubation in the sand medium at $25^{\circ}C$. The higher temperature, $35^{\circ}C$, slightly accelerated the A. suum egg development compared to $25^{\circ}C$, and the development to the 8-cell stage occurred within day 5 after incubation. The formation of larvae in A. suum eggs at temperatures of $35^{\circ}C$ and $25^{\circ}C$ appeared at days 17 and 19 after incubation, respectively. These findings show that $35^{\circ}C$ condition shortens the time for the development of A. suum eggs to the 8-cell-stage in comparison to $25^{\circ}C$, and suggest the possibility of accelerated transmission of this parasite, resulting from global warming and ecosystem changes.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.439-445
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• 2015

A survey of intestinal helminths was undertaken in riparian people in Xieng Khouang Province, Lao PDR. Fecal specimens were collected from 643 people (289 males and 354 females) residing in 4 districts (Nonghet, Kham, Phoukout, and Pek) and were examined by the Kato-Katz technique. The overall helminth egg positive rate was 41.2%, and hookworms revealed the highest prevalence (32.7%) followed by Trichuris trichiura (7.3%) and Ascaris lumbricoides (5.6%). The positive rate for small trematode eggs (STE), which may include Opisthorchis viverrini, heterophyids, and lecithodendriids, was 4.4%. For recovery of adult helminths, 12 STE or nematode/cestode egg-positive people were treated with 40 mg/kg praziquantel and 15 mg/kg pyrantel pamoate, and then purged. Mixed infections with 2 Haplorchis species (H. pumilio and H. taichui), Centrocestus formosanus, Opisthorchis viverrini, a species of cestode (Taenia saginata), and several species of nematodes including hookworms and Enterobius vermicularis were detected. The worm load for trematodes was the highest for H. pumilio with an average of 283.5 specimens per infected person followed by C. formosanus, H. taichui, and O. viverrini. The worm load for nematodes was the highest for hookworms (21.5/infected case) followed by E. vermicularis (3.2/infected case). The results revealed that the surveyed areas of Xieng Khouang Province, Lao PDR are endemic areas of various species of intestinal helminths. The STE found in the surveyed population were verified to be those of heterophyids, particularly H. pumilio.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.133-138
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• 2010

Infection status of intestinal flukes was investigated in residents of Muan-gun, Jeollanam-do, the Republic of Korea. Total 1,257 fecal samples of residents were examined by formalin-ether sedimentation technique and Kato-Katz thick smear method. Helminth eggs were detected from 95 (7.6%) residents, and eggs of heterophyid flukes and Clonorchis sinensis were found from 62 (4.9%) and 40 (3.2%) cases, respectively. The larger heterophyid eggs, somewhat darkbrown in color and $37.7{\times}21.5{\mu}m$ in average size, and found in 32 (2.6%) out of 62 egg positive cases of heterophyid flukes. To confirm the adult flukes, we performed worm recovery from 12 cases after praziquantel treatment and purgation with $MgSO_4$. A total of 1,281 adult flukes, assigned to 7 species, were recovered from 9 cooperative cases. Heterophyes nocens (total 981 specimens) was collected from 9 cases, Stictodora fuscata (80) from 7, Gymnophalloides seoi (75) from 5, Pygidiopsis summa (140) from 3, Stellantchasmus falcatus (3) from 2, and Stictodora lari and Acanthotrema felis (each 1 worm) from 1 case each. The intrauterine eggs of S. fuscata collected from the recovered worm were identical with the larger heterophyid eggs detected in the stool examination. By the present study, it was confirmed that A. felis is a new intestinal fluke infecting humans, and residents in Muan-gun, Jeollanam-do are infected with variable species of intestinal trematodes.

• Parasites, Hosts and Diseases
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• v.45 no.1 s.141
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• pp.39-44
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• 2007

A new endemic focus of Gymnophalloides seoi infection has been discovered on Aphae Island(Shinan-gun, Jeollanam-do), Republic of Korea. This area, which is referred to as Bokyong-ri, is a small seashore village located in the northern portion of the island. Fecal samples were collected from a total of 57 residents and examined by the Kato-Katz and formalin-ether sedimentation techniques. Helminth eggs were detected in 37 samples(64.9%); 33 samples were positive for G. seoi eggs(57.9%), 4 for Pygidiopsis summa(7.0%), 13 for other heterophyids(22.8%), 1 for Clonorchis sinensis(1.7%), and 1 for Trichuris trichiura(1.7%). Women(70.4%) revealed higher rates of G. seoi infection than did men(46.7%), and individuals older than 50 years of age also evidenced higher rates of G. seoi infection than in other age groups(P<0.05). In worm collection from 13 G. seoi egg positive cases, G. seoi (total 86,558 specimens), Heterophyes nocens(278), Stictodora sp.(10), Heterophyopsis continua(3), P. summa(3), and unidentified flukes(42) were collected. Oysters, the source of G. seoi infection, were collected from an area proximal to the village and 50 were examined for metacercariae; 47(94%) were found infected and the observed metacercarial density was $9.5{\pm}8.9$ per oyster. The results of this study indicate that Bokyong-ri is a new endemic area of G. seoi infection, with high rates of infection in humans and oysters.