• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1184-1192
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• 2019

The influenza A virus is a highly infectious respiratory pathogen that sickens many people with respiratory disease annually. To prevent outbreaks of this viral infection, an understanding of the characteristics of virus-host interaction and development of an anti-viral agent is urgently needed. The influenza A virus can infect mammalian species including humans, pigs, horses and seals. Furthermore, this virus can switch hosts and form a novel lineage. This so-called zoonotic infection provides an opportunity for virus adaptation to the new host and leads to pandemics. Most influenza A viruses express proteins that antagonize the antiviral defense of the host cell. The non-structural protein 1 (NS1) of the influenza A virus is the most important viral regulatory factor controlling cellular processes to modulate host cell gene expression and double-stranded RNA (dsRNA)-mediated antiviral response. This review focuses on the influenza A virus NS1 protein and outlines current issues including the life cycle of the influenza A virus, structural characterization of the influenza A virus NS1, interaction between NS1 and host immune response factor, and design of inhibitors resistant to the influenza A virus.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.569-573
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• 2020

Brucellosis is a zoonotic disease caused by Brucella infections and humans usually contract this disease from close contact with infected animals or their products, usually via the ingestion of cheese or crude milk. Macrophage migration inhibitory factor (MIF) and Pro- and anti-inflammatory cytokines play an important role in susceptibility/resistance and the immunopathogenesis of Brucella infection. These cytokines are crucial factors in the initiation and progression of protective immunity against Brucella infection but the role of MIF has not been well studied in the human response to intracellular microbes. This study was designed to investigate the effect of MIF expression on Brucella susceptibility. A total of 85 positive rose Bengal tests and 24 samples from healthy individuals were collected for this study and subjected to polymerase chain reaction assays (PCR) of the bcsp31 diagnostic gene. MIF concentrations were evaluated using Enzyme-Linked immunosorbent assay (ELISA) and the results showed that 46 (54%) of the rose Bengal test samples were positive and 39 (46%) were negative for bcsp31 (p ≤ 0.05) and used as the gold standard for all of the comparisons in this study. The ELISA results indicate that the mean concentration of MIF was significantly higher in patients with positive rose Bengal tests when compared to the control groups and that its concentration increases with increasing age in both the patient and control groups (p ≤ 0.05).

• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.151-156
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• 2024

Bovine borreliosis, caused by Borrelia theileri which is transmitted via hard tick bites, is associated with mild clinical symptoms, such as fever, lethargy, hemoglobinuria, anorexia, and anemia. Borrelia theileri infects various animals, such as cattle, deer, horses, goats, sheep, and wild ruminants, in Africa, Australia, and South America. Notably, no case of B. theileri infection has been reported in Korean cattle to date. In this study, 101 blood samples were collected from a Korean indigenous cattle breed, among which 1.98% tested positive for B. theileri via nested PCR. The obtained sequences exhibited high homology with B. theileri strains identified in other regions. Phylogenetic analysis of 16S rRNA confirmed the B. theileri group affiliation; however, flagellin B sequences exhibited divergence, potentially due to regional evolutionary differences. This study provides the first molecular confirmation of B. theileri infection in Korean livestock. Further isolation and nucleotide sequence analyses are necessary to better understand the presence of B. theileri strains in cows in Korea.

• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.113-117
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• 2015

Cryptosporidium spp., ubiquitous enteric parasitic protozoa of vertebrates, recently emerged as an important cause of economic loss and zoonosis. The present study aimed to determine the distribution and species of Cryptosporidium in post-weaned and adult pigs in Shaanxi province, northwestern China. A total of 1,337 fresh fecal samples of post-weaned and adult pigs were collected by sterile disposable gloves from 8 areas of Shaanxi province. The samples were examined by Sheather's sugar flotation technique and microscopy at${\times}400$ magnification for Cryptosporidium infection, and the species in positive samples was further identified by PCR amplification of the small subunit (SSU) rRNA gene. A total of 44 fecal samples were successfully amplified by the nested PCR of the partial SSU rRNA, with overall prevalence of 3.3%. The average prevalence of Cryptosporidium infection in each pig farms ranged from 0 to 14.4%. Species identification by sequencing of SSU rRNA gene revealed that 42 (3.1%) samples were Cryptosporidium suis and 2 (0.15%) were Cryptosporidium scrofarum. C. suis had the highest prevalence (7.5%) in growers and the lowest in breeding pigs (0.97%). C. suis was the predominant species in pre-weaned and adult pigs, while C. scrofarum infected pigs older than 3 months only. A season-related difference of C. suis was observed in this study, with the highest prevalence in autumn (5.5%) and the lowest (1.7%) in winter. The present study provided basic information for control of Cryptosporidium infection in pigs and assessment of zoonotic transmission of pigs in Shaanxi province, China.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.95-98
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• 2013

Streptococcus suis (S. suis) is a major swine pathogen and an emerging zoonotic agent and is an increasing public health problem across Asia. The present study was undertaken to estimate the antibacterial effect of GR extract and therapeutic effect of GR extract against S. suis infection in mice. At the concentration of GR extract 2.5 mg/ml, the antibacterial effect was not shown on S. suis. However, the antibacterial effect against S. suis was observed at the concentration of GR extract 5.0 mg/ml. Oral administration of GR extract at the dose of 10 mg/kg showed a therapeutic effect for S. suis infected BALB/c mice. The mortality of GR extract-treated mice at the concentration of 5, 10 and 20 mg/kg was 80%, 70%, and 50% at 12 days, respectively, while that of untreated mice was 100% at 8 days after a lethal dose of S. suis infection. The results of our study strongly indicate that GR extract has potential as an effective for S. suis infection in mice.

• Clinical and Experimental Pediatrics
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• v.49 no.9
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• pp.977-982
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• 2006

Purpose : There has been an increasing amount of literature concerning the association between Mycoplasma pneumoniae and asthma pathogenesis. Interleukin(IL)-6 stimulates the differentiation of monocytes, and can promote Th2 differentiation and simultaneously inhibit Th1 polarization. IL-8 is a potent chemoattractant and, it has been suggested, has a role in asthma pathogenesis. Nitric oxide (NO) synthesized by airway epithelium may be important in the regulation of airway inflammation and reactivity. Vascular endothelial growth factor(VEGF) has been reported to be a mediator of airway remodeling in asthma. We investigated the effects of M. pneumoniae on IL-6, IL-8, NO and VEGF production in human respiratory epithelial cells. Methods : A549 cells were cultured and inoculated with M. pneumoniae at a dose of 20 cfu/cell. After infection, the presence of M. pneumoniae in epithelial cell cultures was monitored by immunofluorescence and confirmed by polymerase chain reaction(PCR) detection. IL-6, IL-8 and VEGF were determined by an enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction. NO was measured using the standard Griess reaction. Results : In A549 cells, M. pneumoniaeinduced IL-6, IL-8, NO and VEGF release in time-dependent manners. It also induced mRNA expression of IL-6, IL-8 and VEGF in similar manners. Conclusion : These observations suggest that M. pneumoniae might have a role in the pathogenesis of the allergic inflammation of bronchial asthma.

• Tuberculosis and Respiratory Diseases
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• v.53 no.1
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• pp.71-78
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• 2002

Human toxocariasis is a zoonotic parasitic disease caused by the larva of toxocara canis or cati. It is one of the most commonly reported zoonotic helminth infection in the world. Human are infected mainly by the accidental ingestion of embryonated eggs due to the pica, geophagia, the consumption of contaminated raw vegetables and poor personal hygiene particularly in childhood. In adults, the consumption of raw meat from potential paratenic hosts e.g. chickens, lambs, rabbits and dogs is a major cause of human toxocariasis. The larva can reach various organs such as the liver, lung, brain, and eye by the hematogenous spread and cause visceral larva migrans. We experience a case of pulmonary infiltration with eosinophilia by visceral larva migrans after eating the raw liver and kidney of a dog.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.747-749
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• 2013

The 2 principal species of hookworms infecting humans are Necator americanus and Ancylostoma duodenale. Case studies on zoonotic hookworm infections with Ancylostoma ceylanicum and/or Ancylostoma caninum are known mainly from Asian countries. Of these 2 zoonotic species, only A. ceylanicum can develop to adulthood in humans. In the present study, we report a molecular-based survey of human hookworm infections present in southern and northeastern Thailand. Thirty larval hookworm samples were obtained from fecal agar plate cultures of 10 patients in northeastren Thailand and 20 in southern Thailand. Partial ITS1, 5.8S, and ITS2 regions of the ribosomal DNA genes were amplified using PCR. The amplicons were sequenced, aligned, and compared with other hookworm sequences in GenBank database. The results showed that, in Thailand, N. americanus is more prevalent than Ancylostoma spp. and is found in both study areas. Sporadic cases of A. ceylanicum and A. duodenale infection were seen in northeastern Thailand.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.77-81
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• 2001

Microsporidia in humans emerged with the AIDS epidemic. Enterocytozoon bieneusi is the most significant species' and causes chronic diarrhea, wasting, papillary stenosis, acaculous cholecystitis, bile duct dilatation and sclerosing cholangitis and is responsible for $30-50\%$ of all cases of in people with AIDS. Microsporidiosis has been reported in immunosuppressed, and in immunologically normal individuals. Variety of study has revealed the mode of transmission and possible reservoir of E. bieneusi. Its sites of infection suggest that transmission occurs by ingestion. Transmission has been speculated to occur via infected animals to human, person to person. There is evidence that E. bieneusi occurs in pigs, monkeys, and possibly other animals such as cattle, dogs, cats, llamas and rabbits. E. bieneusi from infected humans has been transmitted experimentally to macaques and to pigs. These observations reflect indirectly the zoonotic nature of E. bieneusi and indicate that cross species transmission is a real possibility. Meanwhile, In recent report, thirty-two percent of the pigs were found to be positive with rates higher over the summer months in US.

• Korean Journal of Veterinary Research
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• v.50 no.3
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• pp.165-169
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• 2010

Recently, the number of stray dogs is proportionate to the increase of the number of the companion dogs. Sarcoptic scabiei var canis, causing scabies, is one of the most important canine zoonotic arthropods in Korea and around the world. Thus, we have tried to know the prevalence of canine scabies in the stray dogs in Korea. A total of 565 stray dogs were collected from the rescue centers all over the country from Jan. 2006 to Dec. 2006. They were grouped with euthanasia or natural death and examined for the gender and age estimated by dental formula. To identify the lesions, the whole body was grossly examined and tested pathologically. Thirty two (5.66%) of 565 dogs were diagnosed as canine scabies. Dogs from urban areas had fewer scabies (0.62%) than those of rural areas (12.5%). Prevalence of scabies in male and female dogs was no difference as 5.96% and 5.25%. Euthanasia group showed higher prevalence (6.48%) than natural death group (2.44%) in scabies. Old dogs over five years showed lower infestration (1.82%) in scabies. In histopathological findings, there were mites in the burrows formed in the subcorneal space. Acanthosis, hyperkeratosis with crust, and vascular dilatation were main findings. One hundred thirteen (20%) of 565 stray dogs were diagnosed to have skin disease. Among them, canine scabies is the most prominent ectoparasite as 5.66 %. With previous reports on human infection in Korea, canine scabies must be regarded as the important zoonotic canine skin disease. Accordingly, for the human and canine hygiene it is imperative that stray dogs with skin problems are segregated and tested for the parasites to treat properly as soon as arriving at rescue shelter.