• Parasites, Hosts and Diseases
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• v.61 no.4
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• pp.463-470
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• 2023

This study aimed to identify the recent risk factors for Opisthorchis viverrini infection and cholangiocarcinoma (CCA) to improve disease prevention. The participants were divided into the following 3 groups based on their health status: healthy control (nonOV and nonCCA), those with O. viverrini infection (OV), and those with CCA. A questionnaire was used to explore their lifestyle and behaviors. Multivariate logistic regression and backward elimination were used to identify the significant risk factors. The results showed that the significant risk factors for both O. viverrini infection and CCA were age>50 years (odd ratio (OR)=8.44, P<0.001, 95% confidence intervals (CI) 2.98-23.90 and OR=43.47, P=0.001, 95% CI 14.71-128.45, respectively) and raw fish consumption (OR=8.48, P<0.001, 95% CI 3.18-22.63 and OR=3.15, P=0.048, 95% CI 1.01-9.86, respectively). A history of O. viverrini infection was identified as an additional risk factor for CCA (OR=20.93, P=0.011, 95% CI 2.04-215.10). This study provided an update on the risk factors for O. viverrini infection and CCA. Asymptomatic patients with O. viverrini infection, particularly those>50 years old, should be carefully monitored to prevent CCA.

• Parasites, Hosts and Diseases
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• v.58 no.6
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• pp.689-694
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• 2020

Strongyloidiasis is caused by Strongyloides stercoralis and is one of the most neglected tropical diseases in tropical and subtropical regions. Although several strongyloidiasis cases have been reported in Korea, genetic analysis of Korean isolates is still incomplete. In this study, a parasite was isolated from a 61-year-old man diagnosed with strongyloidiasis during the treatment of lymphoma on his retroperitoneal lymph node. Diffuse symmetric wall thickening from the ascending to descending colon and a nematode-infected intestine was observed following microscopic examination. Genomic DNA was isolated from a patient tissue block, and S. stercoralis was identified by PCR and sequencing (18S rDNA). In order to determine phylogenetic location of a Korean isolate (named KS1), we analyzed cox1 gene (500-bp) and compared it with that from 47 previous S. stercoralis isolates (28 human isolates and 19 canid isolates) from Asian countries. Our results showed that phylogenetic tree could clearly be divided into 5 different groups according to hosts and regions. KS1 was most closely related with the Chinese isolates in terms of genetic distance.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.295-304
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• 2017

Opisthorchis viverrini infection induces chronic inflammation, and a minor proportion of infected individuals develop advanced periductal fibrosis (APF) and cholangiocarcinoma (CCA). Inflammatory cytokines and/or their gene polymorphisms may link to these biliary pathologies. We therefore investigated associations among cytokine gene polymorphisms and cytokine production in 510 Thai cases infected with O. viverrini who presented with APF+ or APF-, as established by abdominal ultrasonography as well as in patients diagnosed with CCA. Levels of pro-inflammatory and anti-inflammatory cytokines were determined in culture supernatants after stimulation of peripheral blood mononuclear cells (PBMCs) with O. viverrini excretory-secretory (ES) products. Pro-inflammatory cytokines, IL-$1{\beta}$, IL-6, IFN-${\gamma}$, LT-${\alpha}$, and TNF-${\alpha}$ were significantly increased in CCA patients compared with non-CCA (APF- and APF+) cases. Polymorphisms in genes encoding IL-$1{\beta}$-511C/T, IL-6-174G/C, IFN-${\gamma}$+874T/A, LT-${\alpha}$+252A/G, and TNF-${\alpha}$-308G/A were then investigated by using PCR-RFLP or allele specific-PCR (AS-PCR) analyses. In the CCA cases, LT-${\alpha}$+252A/G and TNF-${\alpha}$-308G/A heterozygous and homozygous variants showed significantly higher levels of these cytokines than the wild type. By contrast, levels of cytokines in wild type of IFN-${\gamma}$+874T/A were significantly higher than the variants in CCA cases. IFN-${\gamma}$+874T/A polymorphisms were associated with advanced periductal fibrosis, whereas IL-6-174G/C polymorphisms were associated with CCA. To our knowledge, these findings provide the first demonstration that O. viverrini infected individuals carrying several specific cytokine gene polymorphisms are susceptible to develop fibrosis and CCA.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.2
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• pp.67-76
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• 2016

Dracunculiasis, otherwise known as guinea worm disease (GWD), is caused by infection with the nematode Dracunculus medinensis. This nematode is transmitted to humans exclusively via contaminated drinking water. The transmitting vectors are Cyclops copepods (water fleas), which are tiny free-swimming crustaceans usually found abundantly in freshwater ponds. Humans can acquire GWD by drinking water that contains vectors infected with guinea worm larvae. This disease is prevalent in some of the most deprived areas of the world, and no vaccine or medicine is currently available. International efforts to eradicate dracunculiasis began in the early 1980s. Most dentists and maxillofacial surgeons have neglected this kind of parasite infection. However, when performing charitable work in developing countries near the tropic lines or other regions where GWD is endemic, it is important to consider GWD in cases of swelling or tumors of unknown origin. This paper reviews the pathogenesis, epidemiology, clinical criteria, diagnostic criteria, treatment, and prevention of dracunculiasis. It also summarizes important factors for maxillofacial surgeons to consider.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.109-119
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• 2020

Soil-transmitted helminths and Schistosoma haematobium affect more than 3 billion people globally and mainly occur in sub-Saharan Africa. The present study assessed the overall infection status of a 1716-student cohort of schoolchildren in Zanzibar and applied mass drug administration (MDA) to the cohort from 2007 to 2009. Schools in Pemba, Zanzibar, had a much higher prevalence of soil-transmitted helminth infections than those in Unguja, and the Chaani, Ghana, and Machui schools of Unguja exhibited high S. haematobium infection rates. The MDA program only partially controlled parasite infections, owing to high rates of re-infection. The infection rate of S. haematobium across all 10 schools, for example, was only reduced by 1.8%, and even this change not significant, even though the S. haematobium infection rates of the Chaani and Mzambarauni schools were significantly reduced from 64.4 and 23.4%, respectively, at the first screening, to 7.3 and 2.3% at the last screening. The overall infection rate of Ascaris lumbricoides was reduced from 36.0% at the first screening to 22.6% at the last screening. However, the infection rates for both Trichuris trichiura and hookworm were generally unaffected by MDA. In the future, parasite control programs should involve strategically designed MDA schedules and holistic intervention (e.g., sanitation improvement, hygiene behavior changes, and control of intermediated hosts).

• Parasites, Hosts and Diseases
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• v.61 no.2
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• pp.103-126
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• 2023

In the l950s, under the legacy of traditional agriculture, Ascaris lumbricoides, spread epidemically in the war-bitten society of Korea. Consensus on the parasite control was drafted in the Parasite Disease Prevention Act, which passed a parliamentary agreement in 1966, and established safe disposal of feces and mass chemotherapy as control strategies. Biannual stool examinations and treating infected schoolchildren were basic scheme of the control activity through which revenue could be secured for organized business. In the 27 years following 1969, a maximum of 16 million stool examinations had been done every year. Cellophane thick smear enabled the task. The infection declined remarkably in the 1970s when industrialization and green revolution proceeded. A population study of A. lumbricoides in the late 1970s helped us better understand its epidemiology. The data also settled down the understandable protest of teachers against the repeated stool examinations. In the 9 years following 1987, the target population was gradually reduced when the egg positive rate was below 0.1%. An article in the Korean Law, stipulating obligatory stool examinations, was made optional. Although the long-term Korean effort of Ascaris control was a success, the effect of mass chemotherapy was not as succinct in terms of lowering reinfection. In the period of control, Korean agricultural technology changed, and the economy grew and supplied sanitary facilities by which the vicious cycle was disconnected. Reduction of morbidity was a benefit of mass chemotherapy, which is the only control method feasible in economically difficult countries. The most important hurdle of parasite control in the 1960s was poverty of general population and limited financial resources in Korea but the society formed a consensus on the priority of intestinal helminthiasis control during the ordeal period. The national consensus in the 1960s was the critical milestone for Ascaris control in Korea. Under the social agreement, application of timely technical and research advancements in parasitology achieved the success of ascariasis elimination. The successful experience of ascariasis elimination in Korea can be a benchmark for countries where neglected tropical diseases are endemically recycled.

• Animal Bioscience
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• v.34 no.11
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• pp.1727-1738
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• 2021

Objective: This review consolidates the available information on the socio-economic and ecological significance of Mithun in the lives of ethnic communities in the Eastern Himalaya. Methods: Standard guidelines were followed for the review and data collection was carried out at three stages; literature search, literature screening, and literature review and analysis. Results: Records indicate a long association of Mithun with the ethnic groups. Mithun serves as a symbol of pride and local currency for barter trade in the ethnic society. Its utilities range from being used as a bride price to settling legal disputes. Several cultural festivals and local ceremonies are celebrated around this bovine. Due to its semi-wild nature, this animal also has an ecological role to conserve broad leaf sub-tropical forests. However, it remains neglected and has not received policy attention, leading to a stagnated growth. The institutions for Mithun research and development are also weak. Furthermore, the species is under threat from new diseases and habitat alteration triggered by climate change. Conclusion: Founded on the current state of knowledge, there is a need for institutional development, strengthening institutional linkages, and promoting regional cooperation among Mithun rearing countries for further research and development of this unique cattle.

• Parasites, Hosts and Diseases
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• v.53 no.3
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• pp.271-277
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• 2015

The genetic diversity of Schistosoma haematobium remains largely unstudied in comparison to that of Schistosoma mansoni. To characterize the extent of genetic diversity in S. haematobium among its definitive host (humans), we collected S. haematobium eggs from the urine of 73 infected schoolchildren at 5 primary schools in White Nile State, Sudan, and then performed a randomly amplified polymorphic DNA marker ITS2 by PCR-RFLP analysis. Among 73 S. haematobium egg-positive cases, 13 were selected based on the presence of the S. haematobium satellite markers A4 and B2 in their genomic DNA, and used for RFLP analysis. The 13 samples were subjected to an RFLP analysis of the S. haematobium ITS2 region; however, there was no variation in size among the fragments. Compared to the ITS2 sequences obtained for S. haematobium from Kenya, the nucleotide sequences of the ITS2 regions of S. haematobium from 4 areas in Sudan were consistent with those from Kenya (> 99%). In this study, we demonstrate for the first time that most of the S. haematobium population in Sudan consists of a pan-African S. haematobium genotype; however, we also report the discovery of Kenyan strain inflow into White Nile, Sudan.

• Parasites, Hosts and Diseases
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• v.53 no.5
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• pp.545-551
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• 2015

Schistosomiasis is one of the important neglected tropical diseases (NTDs) in Tanzania, particularly in Lake Victoria zone. This baseline survey was a part of the main study of integrated control of schistosomiasis and soil-transmitted helminths (STHs) aimed at describing morbidity patterns due to intestinal schistosomiasis among adults living on Kome Island, Sengerema District, Tanzania. Total 388 adults from Kome Islands (about 50 people from each village) aged between 12 and 85 years, were examined by abdominal ultrasound according to the Niamey protocol. Liver image patterns (LIPs) A and B were considered normal, and C-F as distinct periportal fibrosis (PPF). The overall prevalence of PPF was 42.2%; much higher in males than in females (47.0% in male vs 34.4% in females, P=0.007). Abnormal increase of segmental branch wall thickness (SBWT) and dilated portal vein diameter (PVD) were also more common in males than in females. Hepatosplenomegaly was frequently encountered; 68.1% had left liver lobe hepatomegaly and 55.2% had splenomegaly. Schistosoma mansoni-related morbidity is quite high among adults in this community justifying the implementation of integrated control strategies through mass drug administration, improved water supply (pumped wells), and health education that had already started in the study area.

• Parasites, Hosts and Diseases
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• v.59 no.2
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• pp.159-165
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• 2021

Bacteremia induced by wound myiasis is uncommon and therefore rarely suspected by clinicians when treating patients with neglected wounds. We present a case of Ignatzschineria larvae bacteremia as a complication of Lucilia sp. maggot wound myiasis in a young male migrant. This is the first reported human case of Ignatzschineria bacteremia in Slovenia and one of the 2 described in the literature where the fly larvae infesting the wounds of the patient with Ignatzschineria bacteremia were not only suspected to be Lucilia sp. but also entomologically identified.