• Parasites, Hosts and Diseases
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• v.56 no.6
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• pp.589-596
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• 2018

Ticks are the vectors of various pathogens, threatening human health and animal production across the globe. Here, for the first time we detected Ricketssia spp., Borrelia spp. and protozoan in ticks from Poyang Lake region in Jiangxi Province of eastern China. In 3 habitat categories and on 12 host species, 311 ticks from 11 species were collected. Haemaphysalis longicornis was the predominant species, accounting for 55.63%, followed by Rhipicephalus microplus, Haemaphysalis flava and Ixodes granulatus. Of the collected ticks, 7.07% were positive for tick-borne pathogens, and H. longicornis and H. flava were found to be co-infected with Ricketssia spp. and protozoan. H. flava was the most detected positive for tick-borne pathogens, whereas H. longicornis had the lowest infection rate, and the difference in infection rates between tick species was significant (${\chi}^2=61.24$, P<0.001). Furthermore, adult ticks demonstrated remarkably greater infection rate than immature ticks (${\chi}^2=10.12$, P=0.018), meanwhile ticks on Erinaceidae showed significantly higher positivity than ticks collected on other host species (${\chi}^2=108.44$, P<0.001). Genetic fragment sequencing and analyses showed at least 4 pathogen species presence in ticks, namely Borrelia yangtzensis, Rickettsia slovaca or Rickettsia raoultii related genospecies, Babesia vogeli and Hepatozoon canis or Hepatozoon felis related genospecies. The finding indicates that the abundant ticks can carry diverse pathogens in Poyang Lake region, and pathogen infection is highly related to species, vertebrate hosts and life stages of ticks.

• Korean Journal of Poultry Science
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• v.19 no.3
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• pp.161-176
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• 1992

Coccidiosis is caused by Eimeria infecting primarily the intestine of the susceptible host, thereby seriously impairing the growth and feed utilization of livestock and poultry. The genus Eimeria contains a number of obligate intracellular protozoan parasites with a complicated life-cycle involving both asexual and sexual stages of development. The desire to develop a vaccine against Eimeria has Promoted active research to elucidate the mechanisms of protective immunity and identification of candidate vaccine antigens. Protozoa are unique in their modes of transmission and nature of disease manifestations, the significance of which should be considered in the development of a control strategy. An intricate and complex interplay of different cell populations and cytokines is involved not only in the pathogenesis of coccidiosis but also in the development of protective immunity Thus, comprehensive understanding of the events leading to protection following Eimeria infection will be crucial for the development of an effective vaccine.

• Parasites, Hosts and Diseases
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• v.52 no.4
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• pp.345-353
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• 2014

Babesia gibsoni is an intraerythrocytic apicomplexan parasite that causes piroplasmosis in dogs. B. gibsoni infection is characterized clinically by fever, regenerative anemia, splenomegaly, and sometimes death. Since no vaccine is available, rapid and accurate diagnosis and prompt treatment of infected animals are required to control this disease. Over the past decade, several candidate molecules have been identified using biomolecular techniques in the authors' laboratory for the development of a serodiagnostic method, vaccine, and drug for B. gibsoni. This review article describes newly identified candidate molecules and their applications for diagnosis, vaccine production, and drug development of B. gibsoni.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.113-120
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• 2010

To understand protozoan, viral, and bacterial infections in diarrheal patients, we analyzed positivity and mixedinfection status with 3 protozoans, 4 viruses, and 10 bacteria in hospitalized diarrheal patients during 2004-2006 in the Republic of Korea. A total of 76,652 stool samples were collected from 96 hospitals across the nation. The positivity for protozoa, viruses, and bacteria was 129, 1,759, and 1,797 per 10,000 persons, respectively. Especially, Cryptosporidium parvum was highly mixed-infected with rotavirus among pediatric diarrheal patients (29.5 per 100 C. parvum positive cases), and Entamoeba histolytica was mixed-infected with Clostridium perfringens (10.3 per 100 E. histolytica positive cases) in protozoan-diarrheal patients. Those infected with rotavirus and C. perfringens constituted relatively high proportions among mixed infection cases from January to April. The positivity for rotavirus among viral infection for those aged $\leq$ 5 years was significantly higher, while C. perfringens among bacterial infection was higher for $\geq$ 50 years. The information for association of viral and bacterial infections with enteropathogenic protozoa in diarrheal patients may contribute to improvement of care for diarrhea as well as development of control strategies for diarrheal diseases in Korea.

• Journal of fish pathology
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• v.25 no.3
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• pp.271-277
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• 2012

The practical monitoring was performed to survey the mortalities in aquaculture farms of olive flounder, rockfish, rainbow trout, Japanese eel, white shrimp and abalone in South Korea from May to November, 2011. The aquatic organism disease inspectors, who have the national licenses for the diagnosis and prevention of aquatic disease and have close relationship with the farms, investigated the rates and causes of mortalities according to the standard manual. In 70 flounder farms, the cumulative mortalities rate was 27.9%, and the mortalities were caused by scuticociliatosis, streptococcosis, VHS, non-infectious loss, vibriosis and gliding bacterial disease. The moralities rate of 30 rockfish farms was 13.6%, and those were mainly contributed by gill flukes and streptococcosis. Most of mortalities of rainbow trout were caused by non-infectious loss and protozoan white spot disease. The mortalities rate of Japanese eel was 0.6% by edwardsiellosis, protozoan white spot disease and gill flukes. The loss rate of white shrimp was 71.2%, and most of them was related with non-infectious ones, such as carnivalization, transportation loss, and the rest was caused by viral white spot disease. The mortalities rate in the abalone farms was 10.7% and all of them were related with non-infectious loss.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.39-39
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• 2003

Balantidiasis is an infectious disease worldwide which is produced by a protozoan Balantidium coli. This single-celled organism is characterized by their large size ranging from 50 $\mu\textrm{m}$ to more than 500 $\mu\textrm{m}$ [1] which indicated by the presence of cilia on its cell surface. The parasite occurs in the lumen of cecum and colon of swine, humans and nonhuman primates as commensal, but can turn opportunist and invade injury tissues by other diseases [2]. It is difficult to diagnose the disease clinically since they are asymptomatic [3]; and can be complicated with other disease or parasitism. Here we report the incidental findings of Balantidiasis in the lymphatic ducts of gastric lymph node of Barbary sheep (Ammotragus lervia). (omitted)

• Genomics & Informatics
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• v.10 no.1
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• pp.9-15
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• 2012

Horizontal gene transfer (HGT) is the movement of genetic material between kingdoms and is considered to play a positive role in adaptation. $Cryptosporidium$ $parvum$ is a parasitic protozoan that causes an infectious disease. Its genome sequencing reported 14 bacteria-like proteins in the nuclear genome. Among them, cgd2_1810, which has been annotated as CysQ, a sulfite synthesis pathway protein, is listed as one of the candidates of genes horizontally transferred from bacterial origin. In this report, we examined this issue using phylogenetic analysis. Our BLAST search showed that $C.$ $parvum$ CysQ protein had the highest similarity with that of proteobacteria. Analysis with NCBI's Conserved Domain Tree showed phylogenetic incongruence, in that $C.$ $parvum$ CysQ protein was located within a branch of proteobacteria in the cd01638 domain, a bacterial member of the inositol monophosphatase family. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, the sulfate assimilation pathway, where CysQ plays an important role, is well conserved in most eukaryotes as well as prokaryotes. However, the Apicomplexa, including $C.$ $parvum$, largely lack orthologous genes of the pathway, suggesting its loss in those protozoan lineages. Therefore, we conclude that $C.$ $parvum$ regained cysQ from proteobacteria by HGT, although its functional role is elusive.

• 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.

• 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.48 no.1
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• pp.9-13
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• 2010

Pentatrichomonas hominis is considered a commensal protozoan in the large intestine of a number of mammalian hosts, such as cats, dogs, and non-human primates. The resulting infections, which can induce diarrhea, have been attributed to opportunistic overgrowth of P. hominis. This study was performed to confirm the P. hominis infection and its molecular characterization from the feces of puppies with diarrhea. Fecal samples were obtained from 14 German shepherd puppies with diarrhea over 1 week (7 females and 7 males, 2-9 months of age) residing on a dog farm in August 2007. Species-specific PCR assay identified P. hominis 18S rRNA genes in 3 of the 14 puppies (1 female and 2 males; 1 aged 2 months and 2 aged 9 months). This phylogenetic analysis established that P. hominis belonged to the 1st clade, which is comprised of Bos taurus and Felines.