• Clinical and Experimental Pediatrics
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• 제59권3호
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• pp.120-125
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• 2016

Purpose: Viral gastroenteritis among children is mainly caused by rotavirus, norovirus, astrovirus, or adenovirus strains. However, changing socioeconomic conditions and a rotavirus vaccination program may be affecting the prevalence of these viral infections. Therefore, we aimed to elucidate the season-specific trends in viral infections for facilitating prophylaxis and surveillance in our region. Methods: We evaluated 345 pediatric patients (203 males, 142 females; age, 1 month to 16 years) who visited the CHA Bundang Medical Center because of gastroenteric symptoms between June 2014 and May 2015. The specimens were simultaneously tested for norovirus, rotavirus, astrovirus, and adenovirus via multiplex reverse transcription polymerase chain reaction. Clinical characteristics of patients were analyzed retrospectively. Results: The most common virus was norovirus, followed by rotavirus, adenovirus, and astrovirus. Of all viral infections, 45.2% occurred mainly between 6 and 24 months of age; in particular, norovirus infection mostly occurred in all age groups except those below 6 months of age, when rotavirus was most prevalent. In addition, seasonal variation was observed, such as norovirus infection from December to February, rotavirus infection from February to April, and adenovirus infection from July to October. Conclusion: Our results showed that the most common cause of acute pediatric viral gastroenteritis had changed from rotavirus to norovirus in our patients, because of effective rotaviral vaccination. We recommend the management of food and personal hygiene in accordance with age or seasons as well as active vaccination for preventing viral gastroenteritis.

• 대한바이러스학회지
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• 제28권4호
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• pp.327-335
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• 1998

Hantaan (HTN) and Seoul (SEO) viruses, murid rodent-borne hantaviruses, are known to causes hemorrhagic fever with renal syndrome (HFRS) in Korea. To determine the genomic diversity and molecular phylogeny of HTN and SEO viruses found in Korea, we amplified for part of M and S genomic segments of hantaviruses from sera of HFRS patients and lung tissues of hantavirus seropositive striped-field mice. Both M and S segment of 16 HTN and 2 SEO viruses were amplified by nested reverse transcription-polymerase chain reaction. Based on 324 nucleotides in the M genomic segment, the HTN and SEO strains showed $93.8{\sim}100%$ and $99.1{\sim}99.4%$ homologies, respectively. Similarly, based on 230 nucleotides in the S genomic segment, HTN and SEO strains showed $90.9{\sim}100%$ and 100% homologies, respectively. Phylogenetic analysis of M and S segments indicated that HTN strains could be divided into at least two main groups in M and S trees and the sequence differences detected among the Sand M genomic segments of HTN viruses are consistent with reassortment having taken place between HTN virus strains.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.170-175
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• 2011

This study was carried out for the molecular level identification of recombinant protein vaccine efficacy, by oral feeding against white spot syndrome virus infection, with the comparison of viral mRNA transcriptional levels in shrimp cells. For the determination of WSSV dilution ratio for the vaccination experiment by oral feeding, in vivo virus titration was carried out using different virus dilutions of virus stock ($1{\times}10^2$, $2{\times}10^2$, and $1{\times}10^3$). Among the dilution ratios, $2{\times}10^2$ diluted WSSV stock was chosen as the optimal condition because this dilution showed 90% mortality at 10 days after virus injection. Recombinant viral proteins, rVP19 and rVP28, produced as protein vaccines were delivered in shrimps by oral feeding. The cumulative mortalities of the shrimps vaccinated with rVP19 and rVP28 at 21 days after the challenge with WSSV were 66.7% and 41.7%, respectively. This indicates that rVP28 showed a better protective effect against WSSV in shrimp than rVP19. Through the comparison of mRNA transcriptional levels of viral genes from collected shrimp organ samples, it was confirmed that viral gene transcriptions of vaccinated shrimps were delayed for 4~10 days compared with those of unvaccinated shrimps. Protection from WSSV infection in shrimp by the vaccination with recombinant viral proteins could be accomplished by the prevention of entry of WSSV due to the shrimp immune system activated by recombinant protein vaccines.

• 미생물학회지
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• 제43권4호
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• pp.285-291
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• 2007

볼티모어의 분류체계에 의하면 바이러스는 복제 및 단백질합성 전략에 따라 6개의 집단으로나눌 수 있다. 몇 종류의 작은 DNA 바이러스를 제외한 대부분의 바이러스는 게놈 복제를 위한 자신의 핵산중합효소를 유전자로 암호화하고 있다. 바이러스 핵산중합효소에는 DNA-의존DNA 중합효수, RNA-의존RNA 중합효소, RNA-의존 DNA 중합효소 세 종류가 있으며, 이들은 모두 4개의 공통된 모티프(motif)를 가진다. 우리는 볼티모어의 분류체계와 바이러스의 핵산중합효소와의 관계를 아미노산 서열을 통해 분자 계통분류학적 분석을 통해 알아보고자 하였다. NCBI GenBank에서 얻은 바이러스 중합효소의 아미노산 서열을 CLUSTAL X 프로그램으로 다중서열하고, Neighbor-joining, Maximum-likelihood, Bayesian의 세 가지 방법으로 계통도를 그려보았다. 미세한 차이는 있었으나, 세 가지 방법 모두에서 볼티모어의 분류법과 일치하는 결과를 보였고, 특이하게도 두 가닥 RNA 바이러스는 숙주의 종류에 따라, (-)RNA 바이러스는 게놈의 절편화에 따라 각각2개의 소집단으로 나뉘어지는 것을 볼 수 있었다.

• IMMUNE NETWORK
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• 제3권2호
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• pp.110-117
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• 2003

Background: The usefulness of DNA vaccine at priming step of heterologous prime-boost vaccination led to DNA vaccine closer to practical reality. DNA vaccine priming followed by recombinant viral vector boosting via systemic route induces optimal systemic immunity but no mucosal immunity. Mucosal vaccination of the reversed protocol (recombinant viral vector priming-DNA vaccine boosting), however, can induce both maximal mucosal and systemic immunity. Here, we tried to address the reason why the mucosal protocol of prime-boost vaccination differs from that of systemic vaccination. Methods: To address the importance of primary immunity induced at priming step, mice were primed with different doses of DNA vaccine or coadministration of DNA vaccine plus mucosal adjuvant, and immunity including serum IgG and mucosal IgA was then determined following boosting with recombinant viral vector. Next, to assess influence of humoral pre-existing immunity on boosting $CD8^+$ T cell-mediated immunity, $CD8^+$ T cell-mediated immunity in B cell-deficient (${\mu}K/O$) mice immunized with prime-boost regimens was evaluated by CTL assay and $IFN-{\gamma}$-producing cells. Results: Immunity primed with recombinant viral vector was effectively boosted with DNA vaccine even 60 days later. In particular, animals primed by increasing doses of DNA vaccine or incorporating an adjuvant at priming step and boosted by recombinant viral vector elicited comparable responses to recombinant viral vector primed-DNA vaccine boosted group. Humoral pre-existing immunity was also unlikely to interfere the boosting effect of $CD8^+$ T cell-mediated immunity by recombinant viral vector. Conclusion: This report provides the important point that optimally primed responses should be considered in mucosal immunization of heterologous prime-boost regimens for inducing the effective boosting at both mucosal and systemic sites.

• 한국수산과학회지
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• 제46권5호
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• pp.582-588
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• 2013

The impact of global warming on aquatic systems has been a priority research area in the past decade. However, the possibility that increased temperatures will cause shifts in viral disease outbreaks has not been well addressed. In the present study, with increasing water temperature (WT) in the coastal area of Korea, we estimated the possibility of changes in fish viral diseases. From the present time, WT may rise between 0.62 and $1.7^{\circ}C$ by 2050, and the effect on aquaculture could be more adverse than benefitial. Red seabream iridovirus disease (RSIVD) and viral nervous necrosis (VNN) cause high mortality above 22 and $24^{\circ}C$, respectively, and outbreaks could commence earlier and persist for prolonged periods. Nevertheless, the period of occurrence of viral hemorrhagic septicemia (VHS), which outbreaks at a lower WT (< $18^{\circ}C$), could be shorter than the current infectious period. Thermal stress in fish causes reductions in growth and immunocompetence; thus, increases in summer WT can lead to the development of new viral diseases. WT has a strong influence on fish population dynamics; therefore, entry of new viruses and changes in the prevalence of infection can be expected if carrier fishes are introduced or migrate to Korean waters.

• Biomolecules & Therapeutics
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• 제26권3호
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• pp.242-254
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• 2018

Defensins are antimicrobial peptides that participate in the innate immunity of hosts. Humans constitutively and/or inducibly express ${\alpha}$- and ${\beta}$-defensins, which are known for their antiviral and antibacterial activities. This review describes the application of human defensins. We discuss the extant experimental results, limited though they are, to consider the potential applicability of human defensins as antiviral agents. Given their antiviral effects, we propose that basic research be conducted on human defensins that focuses on RNA viruses, such as human immunodeficiency virus (HIV), influenza A virus (IAV), respiratory syncytial virus (RSV), and dengue virus (DENV), which are considered serious human pathogens but have posed huge challenges for vaccine development for different reasons. Concerning the prophylactic and therapeutic applications of defensins, we then discuss the applicability of human defensins as antivirals that has been demonstrated in reports using animal models. Finally, we discuss the potential adjuvant-like activity of human defensins and propose an exploration of the 'defensin vaccine' concept to prime the body with a controlled supply of human defensins. In sum, we suggest a conceptual framework to achieve the practical application of human defensins to combat viral infections.

• Molecules and Cells
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• 제41권3호
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• pp.214-223
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• 2018

Oligoadenylate synthetase (OAS) protein family is the major interferon (IFN)-stimulated genes responsible for the activation of RNase L pathway upon viral infection. OAS-like (OASL) is also required for inhibition of viral growth in human cells, but the loss of one of its mouse homolog, OASL1, causes a severe defect in termination of type I interferon production. To further investigate the antiviral activity of OASL1, we examined its subcellular localization and regulatory roles in IFN production in the early and late stages of viral infection. We found OASL1, but not OASL2, formed stress granules trapping viral RNAs and promoted efficient RLR signaling in early stages of infection. Stress granule formation was dependent on RNA binding activity of OASL1. But in the late stages of infection, OASL1 interacted with IRF7 transcripts to inhibit translation resulting in down regulation of IFN production. These results implicate that OASL1 plays context dependent functions in the antiviral response for the clearance and resolution of viral infections.

• Asian Pacific Journal of Cancer Prevention
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• 제16권3호
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• pp.1037-1040
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• 2015

Hepatitis C is a blood-borne infectious disease of liver, caused by a small enveloped, positive-single stranded RNA virus, called the hepatitis C virus (HCV). HCV belongs to the Flaviviridae family and has 6 genotypes and more than 100 subtypes. It is estimated that 185 million people are infected with HCV worldwide and 5% of these are in Pakistan. The study was designed to evaluate different genotypes of HCV circulating in District Mardan and to know about the behavior of these genotypes to different anti-viral regimes. In this study 3,800 patients were exposed to interferon alfa-2a plus Ribavirin treatment for 6-months and subjected to real-time PCR to check the viral response. Among these 3,677 (97%) patients showed no detectable HCV RNA while 123 (3%) patients (non-responders) remained positive for HCV RNA. Genotypes of their analyzed showed that most of them belonged to the 3a genotype. Non-responders (123) and relapsed (5) patients were subjected to PEG-interferon and Ribavirin therapy for next 6 months, which resulted into elimination of HCV RNA from 110 patients. The genotypes of the persisting resistant samples to anti-viral treatment were 3b, 2a, 1a and 1b. Furthermore, viral RNA from 6 patients remained un-typed while 4 patients showed mixed infections. HCV was found more resistant to antiviral therapy in females as compared to mals. The age group 36-45 in both females and males was found most affected by infection. In general 3a is the most prevalent genotype circulating in district Mardan and the best anti-viral therapy is PEG-interferon plus Ribavirin but it is common practice that due to the high cost patients receive interferon alfa-2a plus Ribavirin with consequent resistance in 3% patients given this treatment regime.

• 대한바이러스학회지
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• 제29권1호
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• pp.1-9
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• 1999

Hantaan virus is widely distributed among rodent populations in Korea. Two antigenically distinct hantaviruses were isolated from Apodemus agrarius in 1976 and Rattus norvegicus in 1980 in Korea. This study was designed to investigate the serological evidence of hantavirus infection among indegenous wild rodents, which were captured in 11 mountains located in Kyunggi, Kangwon, Chungnam, Chunbug and Kyungnam province of South Korea. A total 252 wild rodents of 3 species were trapped from Myungsung Mt., Chumbong Mt., Kali Mt., Hansuk Mt., Chachil peak, Kyebang Mt., Odae Mt., Kyerong Mt., Kaya Mt., Togju Mtand Chiri Mtin 1997. Serologic test for hantavirus infection was performed using hantavirus antigens by indirect immunofluorescent antibody techniqueAmong 122 Apodemus agrarius, 88 Apodemus peninsulae and 42 Eothenomys regulus; 18 A. agrarius (14.8%), 12 A. peninsulae (13.6%) and 4 E. regulus (9.5%) were immunofluorescent antibody (IFA) positive against hantaan virus. IFA titers 3 Eothenomys regulus sera were higher against puumalavirus than hantaan virus. These data imply that above three species of rodent might be natural reservoirs of hantaviruses in Korea.