• Parasites, Hosts and Diseases
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• 제54권3호
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• pp.253-259
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• 2016

In the era of (pre) elimination setting, the prevalence of malaria has been decreasing in most of the previously endemic areas. Therefore, effective cost- and time-saving validated pooling strategy is needed for detection of malaria in low transmission settings. In this study, optimal pooling numbers and lowest detection limit were assessed using known density samples prepared systematically, followed by genomic DNA extraction and nested PCR. Pooling strategy that composed of 10 samples in 1 pool, $20{\mu}l$ in 1 sample, was optimal, and the parasite density as low as $2p/{\mu}l$ for both falciparum and vivax infection was enough for detection of malaria. This pooling method showed effectiveness for handling of a huge number of samples in low transmission settings (<9% positive rate). The results indicated that pooling of the blood samples before DNA extraction followed by usual nested PCR is useful and effective for detection of malaria in screening of hidden cases in low-transmission settings.

• 식물병연구
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• 제19권2호
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• pp.114-117
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• 2013

To facilitate their spread, plant viruses have developed several methods for dispersal including insect and seed transmission. While insect transmission requires virus stability against insect digestion, seed-transmitted viruses have to overcome barriers to entry into embryos. Bean pod mottle virus (BPMV) is transmitted through seed at levels typically below 0.1%, but co-infection with Soybean mosaic virus (SMV) enhanced the seed transmission rate of BPMV in one experiment. In contrast, the rate of SMV seed transmission was not affected by BPMV co-infection. In a second preliminary study, the rate of SMV transmission was lower in an isoline of Williams 82 that contained a null mutation for the Kunitz trypsin inhibitor gene than in Williams 82. In this preliminary study, we observed that factors such as protease inhibitor expression and dual infection may affect the frequency of seed transmission of BPMV and SMV.

• Applied Microscopy
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• 제22권1호
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• pp.55-69
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• 1992

Viral disease incidence in the peanut fields at Iri, Kochang, Iksan and Puan in Chonbuk province was 0.93% on July and 8.46% on August in 1991. The causal pathogen was identified as peanut stripe virus (PStV) by the results of host plant reaction, immunological assay and observation of virus particles. Seed transmission rates of collected seeds from diseased plants ranged from 12.9 to 14.8% at peanut fields. PStV transmission was higher in small than in large seeds. Seed transmission of PStV was correlated with the age of the plant when inoculated; infection of young plants resulted in more seed transmission than did infection of old plants. Seed transmission of PStV was correlated with pod formation stages when inoculated at the 45th day after sowing; formed seeds for 2 weeks after inoculation resulted in more seed transmission than did formed seeds after 4 weeks. In seed transmission, this causal virus was moved to embryo and cotyledon through gynophore, pod, and funicle from leaves.

• Journal of Animal Science and Technology
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• 제57권11호
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• pp.32.1-32.8
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• 2015

Peste des petits ruminants (PPR) is considered to be one of the main constraints to enhancing the productivity of goats and sheep in regions where it is present and becoming endemic. PPR was recognized in Pakistan in early 1990s but got importance during the Participatory Disease Surveillance (PDS) of Rinderpest Eradication Campaign. Lot of research work has been initiated during last decade towards disease epidemiology, risk factor recognition, laboratory diagnosis, vaccination and demonstration of control strategies. Although there are ongoing projects working towards the progressive control of the disease in country yet there is need to have a national level control program for PPR. Also there is need to have comprehensive social economic surveys, disease hot spot recognition and identification of role of other species in disease transmission. With combined efforts of local and national authorities and political will, there is high likelihood that this devastating disease can be controlled and eventually eradicated in near future.

• 대한수학회지
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• 제54권3호
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• pp.987-997
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• 2017

A deterministic model for the spread of pine wilt disease with asymptomatic carrier trees in the host pine population is designed and rigorously analyzed. We have taken four different classes for the trees, namely susceptible, exposed, asymptomatic carrier and infected, and two different classes for the vector population, namely susceptible and infected. A complete global analysis of the model is given, which reveals that the global dynamics of the disease is completely determined by the associated basic reproduction number, denoted by $\mathcal{R}_0$. If $\mathcal{R}_0$ is less than one, the disease-free equilibrium is globally asymptotically stable, and in such a case, the endemic equilibrium does not exist. If $\mathcal{R}_0$ is greater than one, the disease persists and the unique endemic equilibrium is globally asymptotically stable.

• IMMUNE NETWORK
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• 제22권3호
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• pp.23.1-23.12
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• 2022

Natural infection with severe acute respiratory syndrome-coronavirus-2 or vaccination induces virus-specific immunity protecting hosts from infection and severe disease. While the infection-preventing immunity gradually declines, the severity-reducing immunity is relatively well preserved. Here, based on the different longevity of these distinct immunities, we develop a mathematical model to estimate courses of endemic transition of coronavirus disease 2019 (COVID-19). Our analysis demonstrates that high viral transmission unexpectedly reduces the rates of progression to severe COVID-19 during the course of endemic transition despite increased numbers of infection cases. Our study also shows that high viral transmission amongst populations with high vaccination coverages paradoxically accelerates the endemic transition of COVID-19 with reduced numbers of severe cases. These results provide critical insights for driving public health policies in the era of 'living with COVID-19.'

• The Plant Pathology Journal
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• 제23권2호
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• pp.57-61
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• 2007

Whitefly-transmitted geminiviruses (WTGs) are economically important pathogens causing serious damage on tomato and chilli pepper in Indonesia. Geminiviruses are readily transmitted by its insect vector, sweetpotato whitefly (Bemisia tabaci). However, greenhouse whitefly (Trialeurodes vaporariorum), another species of whitefly, is commonly found together with B. tabaci in the field. Incidence of yellow leaf curl disease in tomato and chilli pepper is probably correlated with the population of whitefly complex. It is becoming important to find the role of T. vaporariorum in the spread of the disease. Therefore, research is conducted to study the characteristic relationship between tomato leaf curl begomovirus (ToLCV) and two species of whitefly. The two species of whitefly, B. tabaci and T. vaporariorum, was capable to transmit ToLCV although it was evidenced that B. tabaci is more effective as insect vector of ToLCV in tomato and chilli pepper. A single B. tabaci was able to transmit ToLCV to tomato with a minimum acquisition and inoculation access period of 10 h. Transmission of ToLCV by T. vaporariorum required at least 10 insects per plant with a minimum acquisition and inoculation access period of 24 h. The transmission efficiency will increase with longer acquisition and inoculation access period of the insect and the higher number of insect per plant.

• 대한한의학원전학회지
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• 제28권3호
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• pp.27-43
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• 2015

Objectives : Zhang Zhong-jing's Shanghanlun is based on Six-channels system to classified a disease. This paper is planning to describe the Transmutation among Six-channels system. Six-channels change not fixed in either direction and each is relative to each other. Methods : I will try to describe the Transmutation among Six channels system, through the letter of the Shanghanlun. First, I will find letters related to a disease transmission. Second, It will be described through the analysis of the past medical scientists. Results : Six-Meridian Pattern is the categorization of syndromes according to the theory of the six meridians, applied to the diagnosis of acute febrile diseases at different stages, but also useful for the pattern syndrome differentiation of other diseases. Transmutation among Six channels system is not fixed in a certain order and it each affects one another. Conclusions : We can see that Zhong-jing's medical treatment from syndrome differentiation is associated with a Mutual transmission(相互傳變).

• Clinical and Experimental Pediatrics
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• 제64권7호
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• pp.322-327
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• 2021

School closures during the coronavirus disease 2019 (COVID-19) pandemic have been outlined in studies from different disciplines, including economics, sociology, mathematical modeling, epidemiology, and public health. In this review, we discuss the implications of school closures in the context of the current COVID-19 pandemic. Modeling studies of the effects of school closures, largely derived from the pandemic influenza model, on severe acute respiratory syndrome coronavirus 2 produced conflicting results. Earlier studies assessed the risk of school reopening by modeling transmission across schools and communities; however, it remains unclear whether the risk is due to increased transmission in adults or children. The empirical findings of the impact of school closures on COVID-19 outbreaks suggest no clear effect, likely because of heterogeneity in community infection pressure, differences in school closure strategies, or the use of multiple interventions. The benefits of school closings are unclear and not readily quantifiable; however, they must be weighed against the potential high social costs, which can also negatively affect the health of this generation.

• 대한수학회논문집
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• 제34권2호
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• pp.685-699
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• 2019

This research is focused on a continuous epidemic model of transmission of Plasmodium vivax malaria with a time delay. The model is represented as a system of ordinary differential equations with delay. There are two equilibria, which are the disease-free state and the endemic equilibrium, depending on the basic reproduction number, $R_0$, which is calculated and decreases with the time delay. Moreover, the disease-free equilibrium is locally asymptotically stable if $R_0<1$. If $R_0>1$, a unique endemic steady state exists and is locally stable. Furthermore, Hopf bifurcation is applied to determine the conditions for periodic solutions.