• 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.

• Parasites, Hosts and Diseases
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• v.45 no.3
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• pp.233-238
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• 2007

Intestinal helminths and schistosomiasis among school children were investigated in an urban and some rural communities of Ogun State, southwest Nigeria. Fecal samples of 1,059 subjects (524 males, 535 females) aged 3-18 years were examined using direct smear and brine concentration methods between June 2005 and November 2006. The pooled prevalence of infection was 66.2%. Ascaris lumbricoides showed the highest prevalence (53.4%) (P < 0.001) followed by hookworms (17.8%), Trichuris trichiura (10.4%), Taenia sp. (9.6%), Schistosoma mansoni (2.3%), Strongyloides stercoralis (0.7%), Schistosoma haematobium (0.6%), and Enterobius vermicularis (0.3%). The prevalences of A. lumbricoides, hookworms, Taenia sp., S. mansoni, and S. stercoralis in the urban centre were similar (P > 0.05) to those in the rural communities. The fertile and infertile egg ratios of A. lumbricoides in the urban centre and the rural communities were 13: 1 and 3.7: 1, respectively. Each helminth had similar prevalences among both genders (P > 0.05). The prevalence of A. lumbricoides increased significantly with age (P < 0.001). The commonest double infections were Ascaris and hookworms, while the commonest triple infections were Ascaris, hookworms, and Trichuris. The study demonstrates the need for urgent intervention programmes against intestinal helminthiases and schistosomiasis in the study area.

• Parasites, Hosts and Diseases
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• v.52 no.6
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• pp.661-666
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• 2014

In order to investigate the status of intestinal helminthic infections in Cambodia, epidemiological surveys were carried out on a national scale, including 19 provinces. A total of 32,201 fecal samples were collected from schoolchildren and adults between 2006 and 2011 and examined once by the Kato-Katz thick smear technique. The overall egg positive rate of intestinal helminths was 26.2%. The prevalence of hookworms was the highest (9.6%), followed by that of Opisthorchis viverrini/minute intestinal flukes (Ov/MIF) (5.7%), Ascaris lumbricoides (4.6%), and Trichuris trichiura (4.1%). Other types of parasites detected were Enterobius vermicularis (1.1%), Taenia spp. (0.4%), and Hymenolepis spp. (0.2%). The northwestern regions such as the Siem Reap, Oddar Meanchey, and Banteay Meanchey Provinces showed higher prevalences (17.4-22.3%) of hookworms than the other localities. The southwestern areas, including Koh Kong and Preah Sihanouk Provinces showed higher prevalences of A. lumbricoides (17.5-19.2%) and T. trichiura (6.1-21.0%). Meanwhile, the central and southern areas, in particular, Takeo and Kampong Cham Provinces, showed high prevalences of Ov/MIF (23.8-24.0%). The results indicate that a considerably high prevalence of intestinal helminths has been revealed in Cambodia, and thus sustained national parasite control projects are necessary to reduce morbidity due to parasitic infections in Cambodia.

• Parasites, Hosts and Diseases
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• v.51 no.3
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• pp.305-311
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• 2013

In this study, we found that Haplorchis taichui, a heterophyid intestinal fluke, is highly prevalent, with heavy worm loads, among riparian people in Saravane and Champasak province, Lao PDR. Fecal specimens were collected from 1,460 people (717 men and 743 women) in 12 riparian (Mekong river) districts and were examined by the Kato-Katz fecal smear technique. The overall helminth egg positive rate was 78.8% and 66.4% in Saravane and Champasak province, respectively. The positive rate for small trematode eggs (STE), which included H. taichui and other heterophyids, Opisthorchis viverrini, and lecithodendriids, was 69.9% and 46.3% in Saravane and Champasak province, respectively. To obtain adult flukes, 30 STE-positive people were treated with 40 mg/kg praziquantel and then purged. Whole diarrheic stools were collected 4-5 times for each person and searched for fluke specimens using a stereomicroscope. Mixed infections with various species of trematodes (H. taichui, Haplorchis pumilio, O. viverrini, Prosthodendrium molenkampi, Centrocestus formosanus, and Echinochasmus japonicus) and a species of cestode (Taenia saginata) were found. However, the worm load was exceptionally high for H. taichui compared with other trematode species, with an average of 21,565 and 12,079 specimens per infected person in Saravane and Champasak province, respectively, followed by H. pumilio (41.9 and 22.5, respectively) and O. viverrini (9.4 and 1.5, respectively). These results show that diverse species of intestinal and liver flukes are prevalent among riparian people in Saravane and Champasak province, Lao PDR, with H. taichui being the exceptionally dominant species.

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.671-680
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• 2019

Cathepsin D (CatD, EC 3.4.23.5) is a member belonging to the subfamily of aspartic endopeptidases, which are classified into the MEROPS clan AA, family A1. Helminth parasites express a large set of different peptidases that play pivotal roles in parasite biology and pathophysiology. However, CatD is less well known than the other classes of peptidases in terms of biochemical properties and biological functions. In this study, we identified 2 novel CatDs (CsCatD1 and CsCatD2) of Clonorchis sinensis and partially characterized their properties. Both CsCatDs represent typical enzymes sharing amino acid residues and motifs that are tightly conserved in the CatD superfamily of proteins. Both CsCatDs showed similar patterns of expression in different developmental stages of C. sinensis, but CsCatD2 was also expressed in metacercariae. CsCatD2 was mainly expressed in the intestines and eggs of C. sinensis. Sera obtained from rats experimentally infected with C. sinensis reacted with recombinant CsCatD2 beginning 2 weeks after infection and the antibody titers were gradually increased by maturation of the parasite. Structural analysis of CsCatD2 revealed a bilobed enzyme structure consisting of 2 antiparallel β-sheet domains packed against each other forming a homodimeric structure. These results suggested a plausible biological role of CsCatD2 in the nutrition and reproduction of parasite and its potential utility as a serodiagnostic antigen in clonorchiasis.