温度和初始接种量对南方根结线虫侵染力的影响

在棚室盆栽条件下,研究了南方根结线虫在不同温度、不同蔬菜寄主及不同初始接种密度下的症状表现。结果表明,5—9月,气温在22.17~27.61℃之间,南方根结线虫在黄瓜上最短3 d出现明显症状;1—4月和10—12月,气温在15.38~18.67℃之间,15 d出现明显症状,显症时间延迟,发病程度受到抑制。15种感病蔬菜寄主中,以西瓜、甜瓜、苦瓜、黄瓜、南瓜、西葫芦和小青菜症状表现时间比较短,10 d以内表现症状;番茄、豇豆、茄子和甘蓝症状表现时间比较长,15 d出现症状;而韭菜和葱30 d仍未出现明显症状。南方根结线虫对6种蔬菜（黄瓜、番茄、茄子、小青菜、辣椒、韭菜）的侵染能力存在显著差异,黄瓜和番茄的根结百分率、根际二龄幼虫数、雌成虫数和卵块数显著高于茄子、小青菜、辣椒和韭菜。随着二龄幼虫接种密度的增加,番茄感病症状表现时间缩短,相应的病情指数也在增加,在接种量为80头·100g-1（土）时,4 d出现明显症状。接种量为160头·100g-1（土）时超过其饱和数量,发病率和病情指数增加不明显。

马铃薯A病毒不同分离物的侵染鉴定及致病力分析

马铃薯A病毒(Potato virus A,PVA)是马铃薯生产上较常见的病毒之一,植株感病症状与品种、病毒株系和环境条件有关。为研究PVA不同分离物对马铃薯的致病力,将3种遗传背景不同的PVA分离物纯毒源,分别接种到指示植物‘黄花烟’和马铃薯品种‘克新13号’上,应用qRT-PCR检测技术进行病毒侵染鉴定,并观察其致病性差异。结果表明,3种PVA分离物均可成功侵染‘黄花烟’和‘克新13号’,通过接种后‘黄花烟’叶片的症状表现,推断3种分离物的致病性具有一定差异。在马铃薯上分离物2017-171致病力表现为最强,不仅在植株体内病毒含量最高,可致使叶片出现叶缘皱缩、轻花叶,还能导致马铃薯块茎严重裂口、芽眼变深;其次是分离物KB117,病毒侵染速度较快但病毒含量低,植株症状相对明显,叶缘变尖、波浪状皱缩,块茎发生畸形且芽眼变深;最后是分离物2017-176,植株仅个别叶片呈现轻微叶缘皱缩,块茎未出现畸形只存在芽眼变深症状,病毒侵染速度相对慢但病毒含量居中。PVA不同株系的致病性分析为其有效防治提供了有价值的理论依据。

Prevalence and risk factors of asymptomatic hepatitis C virus infection in Egyptian children

AIM: To identify the prevalence, risk factors and manifestations of asymptomatic hepatitis C virus (HCV) infection in Egyptian children. METHODS: Children at the age of 1-9 years were screened for HCV antibodies and alanine aminotransferase (ALT) levels. Every child with elevated ALT and/or detectable HCV antibodies was tested for HCV RNA by RT-PCR and compared with two negative controls for risk factors and signs and symptoms of liver disease.RESULTS: We screened 1042 children, six of them had elevated ALT, negative HCV antibody and positive RNA, likely representing acute hepatitis C cases. Fifteen children were HCV seropositive, 5 of them were HCV RNA positive. Asymptomatic HCV infection was present in 2.02% (positive results for either HCV antibodies or HCV-RNA or both). Symptoms such as diarrhea, abdominal pain, history of fatigue and school absence because of illness and risk factors such as dental care were significantly more common among HCV positive cases than among controls. None of the HCV positive children was diagnosed as having signs of advanced liver disease upon clinical or ultrasonographic examination. CONCLUSION: Asymptomatic HCV infection is detectable in 2.02% Egyptian children.

Role of social distancing in tackling COVID-19 during the first wave of pandemic in Nordic region:Evidence from daily deaths,infections and needed hospital resources

Objectives:To measure the effect of social distancing on reducing daily deaths,infections and hospital resources needed for coronavirus disease 2019(COVID-19)patients during the first wave of the pandemic in Nordic countries.Methods:The observations of social distancing,daily deaths,infections along with the needed hospital resources for COVID-19 patient hospitalizations including the numbers of all hospital beds,beds needed in ICUs and infection wards,nursing staffs needed in ICUs and infection wards were collected from the Institute for Health Metrics and Evaluation(IHME)by the University of Washington.The observations of social distancing were based on the reduction in human contact relative to background levels for each location quantified by cell phone mobility data collected from IHME.The weighted data per 100,000 population gathered in a 40-day period of the first wave of the pandemic in Denmark,Finland,Iceland,Norway and Sweden.Statistical technique of panel data analysis is used to measure the associations between social distancing and COVID-19 indicators in long-run.Results:Results of dynamic long-run models confirm that a 1%rise in social distancing by reducing human contacts may decline daily deaths,daily infections,all hospital beds needed,beds/nurses needed in ICUs and beds/nurses needed in infection wards due COVID-19 pandemic by 1.13%,15.26%,1.10%,1.17%and 1.89%,respectively.Moreover,results of error correction models verify that if the equilibriums between these series are disrupted by a sudden change in social distancing,the lengths of restoring back to equilibrium are 67,62,40,22 and 49 days for daily deaths,daily infections,all hospital beds needed,nurses/beds needed in ICUs and nurses/beds needed in infection wards,respectively.Conclusion:Proper social distancing was a successful policy for tackling COVID-19 with falling mortality and infection rates as well as the needed hospital resources for patient hospitalizations in Nordic countries.The results alert governments of the need for continuously implementing social distancing policies while using vaccines to prevent national lockdowns and reduce the burden of patient hospitalizations.

Case Report:Fulminant type 1 diabetes in China:a case report and review of the literature

Fulminant type 1 diabetes is a recently discovered subtype of idiopathic type 1 diabetes, defined as diabetes with an extremely rapid process of β-cell destruction and progression to hyperglycemia and ketoacidosis. In this report, we present a case of fulminant type 1 diabetes in a 45-year-old Chinese woman, along with a review of the literature. The patient presented with sudden onset of polydipsia and polyuria after flu-like symptoms. Findings on admission included a high blood glucose level and ketoacidosis, but normal HbAlc level. The C-peptide stimulation test showed severe impairment of insulin secretion. Autoantibodies to glutamic acid decarboxylase （GAD） were negative. These results are compatible with the diagnosis of fulminant type 1 diabetes. Human leukocyte antigen-DR7 （HLA-DR7） was available in this case. It is concluded that this rapidly progressing type of diabetes exists, and we propose that HLA-DR7 might be predisposed to fulminant type 1 diabetes in Chinese patients.

Asymptomatic stage of human immunodeficiency virus infection is the optimal timing for its management with Traditional Chinese Medicine

Acquired immune deficiency syndrome(AIDS) is a worldwide public health problem and an incurable disease.The roles of Traditional Chinese Medicine(TCM) on AIDS had been recognized and accepted by more and more people.Being a relatively long period,to initiate combination antiretroviral therapy(cART) for the asymptomatic human immunodeficiency virus(HIV) infection patient is not consensus.According to TCM theory,not only the imbalance of Yin and Yang but also the disharmony of internal body function and external natural environment had occurred in the body of the patient,the imbalance and the disharmony should be adjusted by the means of the treatment based on the patters identified among the symptoms in terms of TCM.We aimed to analyze the feature of patients with asymptomatic infection,and compare the advantages and disadvantages of the usage of cART for asymptomatic infection,explored the possible mechanism underlying TCM treatment of the asymptomatic infection,by reviewing the TCM treatment progress on asymptomatic HIV infection.