• Parasites, Hosts and Diseases
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• v.57 no.4
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• pp.435-437
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• 2019

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and is endemic in many Latin American countries. Diagnosis is based on serologic testing and the WHO recommends two or more serological tests for confirmation. Acidic ribosomal P protein of T. cruzi showed strong reactivity against positive sera of patients, and we cloned the protein after fragmenting it to enhance its antigenicity and solubility. Twelve positive sera of Chagas disease patients were reacted with the fragmented ribosomal P protein using western blot. Detection rate and density for each fragment were determined. Fragments F1R1, F1R2, and F2R1 showed 100% rate of detection, and average density scoring of 2.00, 1.67, and 2.42 from a maximum of 3.0, respectively. Therefore, the F2R1 fragment of the ribosomal P protein of T. cruzi could be a promising antigen to use in the diagnosis of Chagas disease in endemic regions with high specificity and sensitivity.

• Parasites, Hosts and Diseases
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• v.58 no.5
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• pp.589-592
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• 2020

Cyclospora cayetanensis is an apicomplexan protozoan and is one of the most common pathogens causing chronic diarrhea worldwide. Eight stool samples with diarrheal symptom out of 18 Korean residents who traveled to Nepal were obtained, and examined for 25 enteropathogens including 16 bacterial species, 5 viral species, and 4 protozoans in stool samples as causative agents of water-borne and food-borne disease. Only C. cayetanensis was detected by nested PCR, and 3 PCR-positive samples were sequenced to confirm species identification. However, the oocysts of C. cayetanensis in fecal samples could not be detected by direct microscopy of the stained sample. As far as we know, this is the first report of a group infection with C. cayetanensis from a traveler visiting Nepal, and the second report of a traveler's diarrhea by C. cayetanensis imported in Korea.

• Journal of Species Research
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• v.11 no.4
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• pp.335-342
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• 2022

Through the 'Discovery of Korean Indigenous Species' project hosted by the National Institute of Biological Resources (NIBR), new or unrecorded species of various protozoans inhabiting the Korean Peninsula have been discovered. Samples were collected from marine, freshwater, and soil habitats in South Korea and all species were identified and reviewed by experts working on the respective taxonomic group. This study includes 17 unrecorded Korean protozoan species discovered through this project, which belong to four phyla: Amoebozoa Lühe, 1913, Cercozoa Cavalier-Smith, 1998, Euglenozoa Cavalier-Smith, 1981, and Ciliophora Doflein, 1901. Among them, three families (Rhogostomidae Dumack et al., 2017, Parauronematidae Small and Lynn, 1985, and Cyclidiidae Ehrenberg, 1838) and three genera (Rhogostoma Belar, 1921, Parauronema Thompson, 1967, and Cyclidium Müller, 1773) were reported for the first time in Korea. Unlike the previous paper of 2017, this study provides a comprehensive taxonomic account of each species (e.g., species name, collection site, synonyms, specimen vouchers, diagnoses, and figures). Additionally, all the species were assigned Korean names.

• Journal of Veterinary Science
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• v.24 no.1
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• pp.8.1-8.12
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• 2023

Background: Intestinal parasites in livestock cause huge economic setbacks. Moreover, these parasites can threaten human health when also present in companion animals. Objectives: The study examined the prevalence and burden of intestinal parasites among roaming/migrating animals (goats, sheep, cattle, and dogs) to provide insights into the risk of potential human parasitic infections. Methods: A total of 1,741 fecal samples from goats (n = 920), sheep (n = 335), cattle (n = 230) and dogs (n = 256) were obtained randomly across 18 local government areas in Edo State, Nigeria. The parasite samples were recovered and identified under a microscope. Molecular tools were used to identify Toxocara spp. Results: Eighteen different parasites were isolated. Among the different groups of parasites observed, nematodes occurred the most, followed by protozoans. Among nematodes, Haemonchus was most prevalent in goats (28.04%) and sheep (29.85%), while Strongyloides (10.86%) and Bunostomum (8.69%) were relatively high in cattle. Strongyloides (3.9%), hookworm (3.9%), and Toxocara (3.12%) were the predominant parasites in dogs. For protozoan parasites, Eimeria was most common in all 4 animal hosts. Several goats (2.39%) and sheep (2.38%) tested positive for Fasciola spp. Molecular analysis confirmed Toxocara canis in dogs for the first time in Nigeria. Conclusions: The major parasites recovered from these roaming/migrating animals have zoonotic potentials that can threaten human health.

• Parasites, Hosts and Diseases
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• v.61 no.4
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• pp.388-396
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• 2023

Entamoeba histolytica is an enteric tissue-invasive protozoan parasite causing amoebic colitis and liver abscesses in humans. Amoebic contact with host cells activates intracellular signaling pathways that lead to host cell death via generation of caspase-3, calpain, Ca²⁺ elevation, and reactive oxygen species (ROS). We previously reported that various NADPH oxidases (NOXs) are responsible for ROS-dependent death of various host cells induced by amoeba. In the present study, we investigated the specific NOX isoform involved in ROS-dependent death of hepatocytes induced by amoebas. Co-incubation of hepatoma HepG2 cells with live amoebic trophozoites resulted in remarkably increased DNA fragmentation compared to cells incubated with medium alone. HepG2 cells that adhered to amoebic trophozoites showed strong dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence, suggesting intracellular ROS accumulation within host cells stimulated by amoebic trophozoites. Pretreatment of HepG2 cells with the general NOX inhibitor DPI or NOX2-specific inhibitor GSK 2795039 reduced Entamoeba-induced ROS generation. Similarly, Entamoeba-induced LDH release from HepG2 cells was effectively inhibited by pretreatment with DPI or GSK 2795039. In NOX2-silenced HepG2 cells, Entamoeba-induced LDH release was also significantly inhibited compared with controls. Taken together, the results support an important role of NOX2-derived ROS in hepatocyte death induced by E. histolytica.

• Animal Bioscience
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• v.37 no.1
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• pp.1-15
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• 2024

Poultry coccidiosis is an intestinal infection caused by an intracellular parasitic protozoan of the genus Eimeria. Coccidia-induced gastrointestinal inflammation results in large economic losses, hence finding methods to decrease its prevalence is critical for industry participants and academic researchers. It has been demonstrated that coccidiosis can be effectively controlled and managed by employing anticoccidial chemical compounds. However, as a result of their extensive use, anticoccidial drug resistance in Eimeria species has raised concerns. Phytochemical/herbal medicines (Artemisia annua, Bidens pilosa, and garlic) seem to be a promising strategy for preventing coccidiosis, in accordance with the "anticoccidial chemical-free" standards. The impact of herbal supplements on poultry coccidiosis is based on the reduction of oocyst output by preventing the proliferation and growth of Eimeria species in chicken gastrointestinal tissues and lowering intestinal permeability via increased epithelial turnover. This review provides a thorough up-to-date assessment of the state of the art and technologies in the prevention and treatment of coccidiosis in chickens, including the most used phytochemical medications, their mode of action, and the applicable legal framework in the European Union.

• Parasites, Hosts and Diseases
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• v.42 no.4
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• pp.205-208
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• 2004

Neutrophils are important effector cells against protozoan extracellular parasite Entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. Apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. This study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by Entamoeba histolytica. Isolated human neutrophils from the peripheral blood were incubated with or without live trophozoites of E. histolytica and examined by transmission electron microscopy (TEM). Neutrophils incubated with E. histolytica were observed to show apoptotic characteristics, such as compaction of the nuclear chromatin and swelling of the nuclear envelop. In contrast, neutrophils incubated in the absence of the amoeba had many protrusions of irregular cell surfaces and heterogenous nuclear chromatin. Therefore, it is suggested that Entamoeba-induced neutrophil apoptosis contribute to prevent unwanted tissue inflammation and damage in the amoeba-invaded lesions in vivo.

• Parasites, Hosts and Diseases
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• v.42 no.4
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• pp.185-193
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• 2004

Toxoplasma gondii is an obligate intracellular protozoan parasite, which invades a wide range of hosts including humans. The exact mechanisms involved in its invasion are not fully understood. This study focused on the roles of $Ca^{2+}$ in host cell invasion and in T. gondii replication. We examined the invasion and replication of T. gondii pretreated with several calcium modulators, the conoid extrusion of tachyzoites. Calmodulin localization in T. gondii were observed using the immunogold method, and $Ca^{2+}$ levels in tachyzoites by confocal microscopy. In light microscopic observation, tachyzoites co-treated with A23187 and EGTA showed that host cell invasion and intracellular replication were decreased. The invasion of tachyzoites was slightly inhibited by the $Ca^{2+}$ channel blockers, bepridil and verapamil, and by the calmodulin antagonist, calmidazolium. We observed that calcium saline containing A23187 induced the extrusion of tachyzoite conoid. By immunoelectron microscopy, gold particles bound to anti-calmodulin or anti-actin mAb, were found to be localized on the anterior portion of tachyzoites. Remarkably reduced intracellular $Ca^{2+}$ was observed in tachyzoites treated with BAPTA/AM by confocal microscopy. These results suggest that host cell invasion and the intracellular replication of T. gondii tachyzoites are inhibited by the calcium ionophore, A23187, and by the extracellular calcium chelator, EGTA.

• Parasites, Hosts and Diseases
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• v.54 no.1
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• pp.93-96
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• 2016

Toxoplasmosis, a neglected tropical disease caused by the protozoan parasite Toxoplasma gondii, occurs throughout the world. Human T. gondii infection is asymptomatic in 80% of the population; however, the infection is life-threatening and causes substantial neurologic damage in immunocompromised patients such as HIV-infected persons. The major purpose of this study was to investigate the seroprevalence of T. gondii infection in subjects infected with HIV/AIDS in eastern China. Our findings showed 9.7% prevalence of anti-T. gondii IgG antibody in HIV/AIDS patients, which was higher than in intravenous drug users (2.2%) and healthy controls (4.7%), while no significant difference was observed in the seroprevalence of anti-Toxoplasma IgM antibody among all participants (P>0.05). Among all HIV/AIDS patients, 15 men (7.7%) and 10 women (15.9%) were positive for anti-T. gondii IgG antibody; however, no significant difference was detected in the seroprevalence of anti-Toxoplasma IgG antibody between males and females. The frequency of anti-Toxoplasma IgG antibody was 8.0%, 13.2%, 5.5%, and 0% in patients with normal immune function ($CD4^+$ T-lymphocyte count ${\geq}500cells/ml$), immunocompromised patients (cell count ${\geq}200$ and <500 cells/ml), severely immunocompromised patients (cell count ${\geq}50$ and <200 cells/ml), and advanced AIDS patients, respectively (cell count <50 cells/ml), while only 3 immunocompromised patients were positive for anti-T. gondii IgM antibody. The results indicate a high seroprevalence of T. gondii infection in HIV/AIDS patients in eastern China, and a preventive therapy for toxoplasmosis may be given to HIV/AIDS patients based on $CD4^+$ T lymphocyte count.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.111-115
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• 2007

Entamoeba histolytica (E. histolytica) is a worldwide protozoan parasite causing a wide rage of intestinal disease in human, including asymptomatic cyst carriage, acute diarrhea, fulminant dysentery, and chronic nondysenteric colitis. Extraintestinal amebiasis such as hepatic abscess also occurs. Spread of the infection occurs due to consumption of food and water that is contaminated with the cyst. Amebiasis is rarely reported in the newborn period. We report a case of a 6-day-old female newborn with watery diarrhea that progressed to bloody mucoid diarrhea with persistent fever. The fresh stool microscopic examination disclosed E. histolytica trophozoites. She was born of spontaneous vaginal delivery at 41 weeks of gestation after premature rupture of membrane. She was given breast-feeding after birth, then entered postpartum care center. Her mother's stool microscopic examination showed negative result. Infection might have occurred from giving sweetened water following birth or contamination of the baby's bottles at the postpartum care center. She was treated with oral metronidazole for 24 days.