• 제목/요약/키워드: Experimental infection

검색결과 1,049건 처리시간 0.023초

Validation of an Anthracnose Forecaster to Schedule Fungicide Spraying for Pepper

  • Ahn, Mun-Il;Kang, Wee-Soo;Park, Eun-Woo;Yun, Sung-Chul
    • The Plant Pathology Journal
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    • 제24권1호
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    • pp.46-51
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    • 2008
  • With the goal of achieving better integrated pest management for hot pepper, a disease-forecasting system was compared to a conventional disease-control method. Experimental field plots were established at Asan, Chungnam, in 2005 to 2006, and hourly temperature and leaf wetness were measured and used as model inputs. One treatment group received applications of a protective fungicide, dithianon, every 7 days, whereas another received a curative fungicide, dimethomorph, when the model-determined infection risk (IR) exceeded a value of 3. In the unsprayed plot, fruits showed 18.9% (2005) and 14.0% (2006) anthracnose infection. Fruits sprayed with dithianon at 7-day intervals had 4.7% (2005) and 15.4% (2006) infection. The receiving model-advised sprays of dimethomorph had 9.4% (2005) and 10.9% (2006) anthracnose infection. Differences in the anthracnose levels between the conventional and model-advised treatments were not statistically significant. The efficacy of 10 (2005) and 8 (2006) applications of calendar-based sprays was same as that of three (2005 and 2006) sprays based on the disease-forecast system. In addition, we found much higher the IRs with the leaf wetness sensor from the field plots comparing without leaf wetness sensor from the weather station at Asan within 10km away. Since the wetness-periods were critical to forecast anthracnose in the model, the measurement of wetness-period in commercial fields must be refined to improve the anthracnose-forecast model.

Is Pneumocystis carinii vertically transmitted to neonatal rats?

  • Hong, Sung-Tae;Park, Yun-Kyu;Kim, Jin;Kim, Dug-Ha;Yun, Chong-Ku
    • Parasites, Hosts and Diseases
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    • 제37권3호
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    • pp.149-156
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    • 1999
  • Pneumocystis carinii is pulmonary pathogen of immunocompromised humans or other mammals. Its infection results from activation of organism involves in latent infection or form new infection through the air. Almost all children are known to be infected within 2 to 4 years of birth, though prenatal transplacental transmission has not yet been demonstrated. In this study we observed experimental P.carinii infection in neonatal rats, thus investigating the possibility of transplacental vertical transmission by Diff-Quik staining of the lung impression smears and in-sity hybridization for lung sections. The postive rate of P.carinii infection in immunosuppressed maternal rats was 100%, but that in normal maternal rats was 0%. Cystic forms of P.carinii were observed in three of six 1-week old neonatal rats born of heavily infected mothers, but none of them was positive by in-situ hybridization. Five weeks after birth, cystic forms were detected in four neonatal rats. In the lobes of the lungs, no predilection site of P.carinii was recognized. Counts of cystic forms on smears and the reactivity of in-situ hbridization in the lungs of neonatal rats 0 were signficantly lower than in maternal rats. The present findings suggest that P.carinii is rarely transmitted through the placenta and proliferates less successfully in the lungs of neonatal rats than in mothers.

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Prevalence of human parechovirus and enterovirus in cerebrospinal fluid samples in children in Jinju, Korea

  • Seo, Ji-Hyun;Yeom, Jung Sook;Youn, Hee-Shang;Han, Tae-Hee;Chung, Ju-Young
    • Clinical and Experimental Pediatrics
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    • 제58권3호
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    • pp.102-107
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    • 2015
  • Purpose: Human parechovirus (HPeV) and enterovirus (EV) are causative agents of a sepsis-like illness in neonates and of infections of the central nervous system in young children. The objectives of this study were to assess the prevalence of HPeV3 and EV infection in young children with a sepsis-like illness or with meningitis in Jinju, Korea. Methods: Cerebrospinal fluid (CSF) samples were collected from 267 patients (age range, 1 day to 5 years) and assessed for HPeV and EV by performing reverse transcription polymerase chain reaction assay. Amplification products of the VP3/VP1 region of HPeV and of the VP1 region of EV were sequenced to identify the virus type. Results: HPeV and EV were detected in 3.4% and 7.5% of the total CSF samples assessed, respectively. The age distribution of EV-positive patients (median age, 1.4 months) had a significantly broader range than that of HPeV-positive patients (median age, 7.8 months). The peak seasons for HPeV and EV infection were spring and summer, respectively. The clinical symptoms for HPeV and EV infection were similar, and fever was the most common symptom. Pleocytosis was detected in 22.2% of HPeV-positive patients and 35.5% of EV-positive patients. The VP3/VP1 gene sequence of the nine Korean strains clustered most closely with the Japanese strain (AB759202). Conclusion: The data indicate that HPeV infection is predominant in young infants (<6 months) and that meningitis without pleocytosis was caused by both HPeV and EV infection in children.

Prevalence of respiratory viral infection in children hospitalized for acute lower respiratory tract diseases, and association of rhinovirus and influenza virus with asthma exacerbations

  • Kwon, Jang-Mi;Shim, Jae Won;Kim, Deok Soo;Jung, Hye Lim;Park, Moon Soo;Shim, Jung Yeon
    • Clinical and Experimental Pediatrics
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    • 제57권1호
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    • pp.29-34
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    • 2014
  • Purpose: In this study, we aimed to investigate the prevalence of year-round respiratory viral infection in children with lower respiratory tract infection (LRTI) and the relationship between respiratory viral infection and allergen sensitization in exacerbating asthma. Methods: We investigated the sources for acute LRTIs in children admitted to our hospital from May 2010 to April 2011. The 6 most common respiratory viruses were isolated from nasopharyngeal aspirate using multiplex reverse transcription-polymerase chain reaction in 309 children; respiratory syncytial virus (RSV), adenovirus (AV), parainfluenza virus (PIV), influenza virus (IFV), human metapneumovirus (hMPV), rhinovirus (RV). Atopic sensitization was defined if more than 1 serum specific Immunoglobulin E level measured using UniCAP (Pharmacia) was over 0.35 IU/mL. Results: RSV was the most common pathogen of bronchiolitis in hospitalized children through the year. RV or IFV infection was more prevalent in asthma exacerbations compared to other LRTIs. AV and hMPV were more likely to cause pneumonia. RV and IFV were associated with asthma exacerbations in children with atopic sensitization, but not in nonatopic children. Conclusion: RV and IFV are associated with hospitalization for asthma exacerbation in children with atopic sensitization.

Performance of Growing Goats Experimentally Infected with Stomach Worm (Haemonchus contortus)

  • Howlader, M.M.R.;Capitan, S.S.;Eduardo, S.L.;Roxas, N.P.;Sevilla, C.C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제10권5호
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    • pp.534-539
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    • 1997
  • A uniform group of 12 upgrade grower goats of 6.0 -7.5 months old were used in this study. They were equally divided into three groups of $T_1$, $T_2$ and $T_3$ and were infected orally with three levels (0, 5,000 and 10,000 larvae) of infective Haemonchus contortus larvae. Before infection, all animals were housed in individual pens with concrete floor. They were provided with a uniform management. Comparison of body weight changes of infected and uninfected grower goats were done using weekly body weights. There was significant (p < 0.01) interaction between the effect of stomach worm infection and duration of infection on body weight. The infected groups (2 and 3) weighed significantly (p < 0.05) less than the control group from week 18 to 21. The animals of control group gained an average of 2.85 kg with 18.75 g average daily gain (ADG) in 152 days, which were significantly higher than those of animals in the infected groups. There was significant effect of H. contortus infection on the pres laughter weights of grower goats. The hot carcass weights of the infected goats were significantly lower than the uninfected group. No significant difference in dressing percentage of infected and uninfected groups was observed.

Eosinophil and IgE responses of IL-5 transgenic mice experimentally infected with Nippostrongylus brasiliensis

  • Chai, Jong-Yil;Shin, Eun-Hee;Takatsu, Kiyoshi;Matsumoto, Naoki;Kojima, Somei
    • Parasites, Hosts and Diseases
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    • 제37권2호
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    • pp.93-99
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    • 1999
  • Eosinohil and IgE responses of interleukin IL(-5 transgenic and normal C3H/HeN mice were studied after experimental infection with Nippostrongylus brasiliensis 9Nb). Intestinal worms were recovered at day 5 post-infection (PI), and numbers of total white blood cells (WBC) and eosinophils, and total serum IgE and anti-hapten (dinitrophenyl)(DNP) specific IgE titers, were measured at days 0,14 and PI. IL-5 mice appeared resistant to Nb infection showing a significantly ower worm recovery rate than normal mice (P<0.05). Total WBC and eosinophil counts (/mm3) were significantly increased in Nb infected normal mice (p<0.05), but unchanged (total WBC) or decreased (eosinophils) in IL-5 mice at day 21 PI. The total serum IgE level remarkably increased in normal mice, but only a little in IL-5 mice at days 14 and 21 PI. Priming with DNP brought about more remarkable increases of the total and anti-DNP specific IgE in normal mice than in IL-5 mice. The results show that IL-5 mice are resistant to Nb infection, and that eosinophil and IgE responses in these mice are not augmented by N infection.

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Mucosal Immune Responses of Mice Experimentally Infected with Pygidiopsis summa (Trematoda: Heterophyidae)

  • Chai, Jong-Yil;Park, Young-Jin;Park, Jae-Hwan;Jung, Bong-Kwang;Shin, Eun-Hee
    • Parasites, Hosts and Diseases
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    • 제52권1호
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    • pp.27-33
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    • 2014
  • Mucosal immune responses against Pygidiopsis summa (Trematoda: Heterophyidae) infection were studied in ICR mice. Experimental groups consisted of group 1 (uninfected controls), group 2 (infection with 200 metacercariae), and group 3 (immunosuppression with Depo-Medrol and infection with 200 metacercariae). Worms were recovered in the small intestine at days 1, 3, 5, and 7 post-infection (PI). Intestinal intraepithelial lymphocytes (IEL), mast cells, and goblet cells were counted in intestinal tissue sections stained with Giemsa, astra-blue, and periodic acid-Schiff, respectively. Mucosal IgA levels were measured by ELISA. Expulsion of P. summa from the mouse intestine began to occur from days 3-5 PI which sustained until day 7 PI. The worm expulsion was positively correlated with proliferation of IEL, mast cells, goblet cells, and increase of IgA, although in the case of mast cells significant increase was seen only at day 7 PI. Immunosuppression suppressed all these immune effectors and inhibited worm reduction in the intestine until day 7 PI. The results suggested that various immune effectors which include IEL, goblet cells, mast cells, and IgA play roles in regulating the intestinal mucosal immunity of ICR mice against P. summa infection.

The Methanol Extract of Azadirachta indica A. Juss Leaf Protects Mice Against Lethal Endotoxemia and Sepsis

  • Kim, Woong-Hyun;Song, Hyun-Ok;Jin, Chun-Mei;Hur, Jong-Moon;Lee, Hwa-Sung;Jin, Han-Yong;Kim, Sung-Yeon;Park, Hyun
    • Biomolecules & Therapeutics
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    • 제20권1호
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    • pp.96-103
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    • 2012
  • In the present study, the inhibitory effect of neem leaf extract (NLE) on lipopolysaccaride (LPS)-induced nitric oxide (NO) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) production was examined both in vitro and in vivo. In vitro study revealed that NLE treatment ($100{\mu}g/ml$) inhibits LPS (100 ng/ml)-induced NO production by 96% and TNF-${\alpha}$ production by 32%. The reduction in NO production is probably conferred by the complete suppression of inducible nitric oxide synthase (iNOS) expression. Interestingly, in vivo NLE significantly improved the survival rate of mice in an experimental sepsis model. Administration of NLE (100 mg/kg) 24 h before LPS treatment (20 mg/kg) improved the survival rate of mice by 60%. The inhibition of plasma NO and TNF-${\alpha}$ production by NLE is likely to account for the improved survival of mice. Our results suggest that NLE may present a promising avenue in the development of therapeutic agents for the treatment of inflammatory diseases.

국내 양식 뱀장어(Anguilla japonica, Anguilla bicolor and Anguilla marmorata)의 JEECV (Japanese Eel Endothelial Cell-infecting Virus)와 AnHV (Anguillid Herpesvirus 1) 감염 현황 및 특성 연구 (Status and Characteristics of JEECV (Japanese Eel Endothelial Cell-infecting Virus) and AnHV (Anguillid Herpesvirus 1) Infections in Domestic Farmed Eels Anguilla japonica, Anguilla bicolor and Anguilla marmorata)

  • 장문희;이남실;조미영;송준영
    • 한국수산과학회지
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    • 제54권5호
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    • pp.668-675
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    • 2021
  • The infection status of domestic farmed eels Anguilla japonica, Anguilla bicolor and Anguilla marmorata with Japanese eel endothelial cell-infecting virus (JEECV) and anguillid herpesvirus 1 (AnHV) was examined at the major eel farming areas in Korea. These viruses were detected in all areas examined, regardless of the eel species or age. Any farm with a history of viral infection in adult fish confirmed the infection to be transmitted to stocked fry within 3 to 5 months. It is proposed that both viruses are horizontally transmitted within a given farm. The primary symptoms and histopathological lesions produced by the two viral infections are similar, making it difficult to distinguish the two diseases through clinical symptoms. Both viruses displayed 100% detection in the gills, suggesting that the gills are an optimal tissue for JEECV and AnHV monitoring. This study concluded that JEECV and AnHV were prevalent on eel farms across the country and caused very high mortality when the two viruses co-infected fry. Additional studies, including experimental infections, are needed to clearly understand the pathogenicity of each virus and the risk of co-infection.

중소병원 대상 다제내성균 감염관리 시뮬레이션 프로그램 개발 및 적용 (Development and Application a Multidrug Resistant Organisms Infection Control Simulation Program for Small and Medium-sized Hospital)

  • 이미향;김재연
    • 디지털융복합연구
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    • 제19권4호
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    • pp.159-166
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    • 2021
  • 본 연구는 중소병원 간호사를 대상으로 다제내성균 감염관리 시뮬레이션 프로그램을 개발하고 개발된 다제내성균 감염관리 시뮬레이션 교육 프로그램의 효과를 평가하기 위해 시도되었다. 본 연구는 중소병원에 근무하는 간호사 33명을 대상으로 시행한 단일군 전·후 실험설계연구이다. 수집된 자료는 IBM SPSS 21.0 프로그램을 이용하여 분석하였으며 대상자의 일반적 특성, 다제내성균 감염관리 지식과 수행도는 기술통계 분석하였고 프로그램 적용 전후 지식과 수행도의 차이는 paired t-test로 분석하였다. 연구결과 시뮬레이션 프로그램 적용 후 간호사의 다제내성균 감염관리 지식(t=-10.764, p<.001)과 감염관리 수행도(t=-4.215, p<.001)가 통계적으로 유의하게 높아졌다. 의료기관 내 다제내성균 전파 차단 및 유행발생을 예방하기 위해 간호사의 감염관리 지식과 수행도 향상이 중요하므로 향후 다양한 시뮬레이션 프로그램 개발이 필요하다.