Latency characteristics in specific pathogen-free chickens 21 and 35 days after intra-tracheal inoculation with vaccine or field strains of infectious laryngotracheitis virus

ABSTRACT

Latency is an important feature of infectious laryngotracheitis virus (ILTV) yet is poorly understood. This study aimed to compare latency characteristics of vaccine (SA2) and field (CL9) strains of ILTV, establish an in vitro reactivation system and examine ILTV infection in peripheral blood mononuclear cells (PBMC) in specific pathogen-free chickens. Birds were inoculated with SA2 or CL9 ILTV and then bled and culled at 21 or 35 days post-inoculation (dpi). Swabs (conjunctiva, palatine cleft, trachea) and trigeminal ganglia (TG) were examined for ILTV DNA using PCR. Half of the TG, trachea and PBMC were co-cultivated with cell monolayers to assess in vitro reactivation of ILTV infection. ILTV DNA was detected in the trachea of approximately 50% of ILTV‐inoculated birds at both timepoints. At 21?dpi, ILTV was detected in the TG only in 29% and 17% of CL9- and SA2-infected birds, respectively. At 35?dpi, ILTV was detected in the TG only in 30% and 10% of CL9- and SA2-infected birds, respectively. Tracheal organ co-cultures from 30% and 70% of CL9- and SA2-infected birds, respectively, were negative for ILTV DNA at cull but yielded quantifiable DNA within 6 days post-explant (dpe). TG co-cultivation from 30% and 40% of CL9-and SA2-infected birds, respectively, had detectable ILTV DNA within 6 dpe. Latency characteristics did not substantially vary based on the strain of virus inoculated or between sampling timepoints. These results advance our understanding of ILTV latency and reactivation.

RESEARCH HIGHLIGHTS

• Following inoculation, latent ILTV infection was detected in a large proportion of chickens, irrespective of whether a field or vaccine strain was inoculated.

• In vitro reactivation of latent ILTV was readily detected in tracheal and trigeminal ganglia co-cultures using PCR.

• ILTV latency observed in SPF chickens at 21 days post-infection was not substantially different to 35 days post-infection.

     

2005-2019年理塘县法定传染病疫情分析

目的了解理塘县近15年法定传染病疫情形势及流行特征,为政府制定防控措施提供科学依据。方法对2005—2019年理塘县法定传染病疫情进行描述性流行病学分析。采用ArcGIS 10.3软件绘制各乡镇发病情况分布图,SPSS 21.0软件进行χ²检验、趋势性χ²检验。结果2005—2019年理塘县共计报告甲乙丙类传染病21种6154例,年均发病率为644.33/10万,发病呈上升趋势。死亡37例,年均死亡率3.87/10万,病死率0.60%。呼吸道传染病发病最高(341.12/10万);发病前3位的病种为肺结核(271.91/10万)、乙肝(103.24/10万)及包虫病(67.22/10万);肺结核、其他感染性腹泻病、艾滋病/HIV、梅毒发病呈上升趋势。3月、9月分别出现1次发病高峰;20~29岁、30~39岁和10~19岁组发病居前3位;男女性别比为1.24∶1;发病以农民、牧民及学生为主。结论2005-2019年理塘县法定传染病发病率较高且呈上升趋势,应针对高发传染病、上升趋势明显的传染病、重点人群进行分析研究,采取针对性措施控制疫情。     

基于新发重大传染病的医院运营优化策略及政策建议

简要梳理了新发重大传染病对医院运营的影响,并从布局及流程管理、应急资源管理、人力资源管理、绩效分配管理、经济管理及信息化建设6个方面提出优化策略,同时从加强传染病基础设施建设、规划传染病救治中心、鼓励一院多区模式、建设应急物资储备库、完善应急资源保障体系、给予医院适当财政支持方面提出政策建议,以期为新发重大传染病背景下医院的运营优化提供参考借鉴。     

深圳市L区社区糖尿病患者自我管理模式探讨*

摘 要：目的：分析手足口病聚集性疫情在人群中的发生情况和分布特征。方法：收集2018年1月—2020年12月苏州 市各市 （区） 疾病预防控制中心每月上报的手足口病聚集性疫情信息,进行描述性统计分析。结果：2018—2020年苏州市共 报告手足口病聚集性疫情1 006起,报告病例3 129例,其中57.06%的疫情涉及2例病例。疫情发生的高峰期为每年的5—6月 和9月;报告疫情起数排在前三位的市 （区） 分别为张家港市、吴中区和太仓市;89.46%的疫情发生在幼托机构。采集342 起疫情的867例标本进行实验室检测,检出阳性病原的326起,占95.32%。阳性疫情以柯萨奇病毒A组6型 （CoxA6） 为主, 其次为柯萨奇病毒 A 组 16 型 （CoxA16）。结论：手足口病聚集性疫情呈现明显的双峰分布,幼托机构是疫情防控的重点场 所,病原存在单一感染和混合感染,不同年份病原构成存在差异。     

Ten years of Pan-InfORM: modelling research for public health in Canada

Modelling and simulation methods can play an important role in guiding public health responses to infectious diseases and emerging health threats by projecting the plausible outcomes of decisions and interventions. The 2003 SARS epidemic marked a new chapter in disease modelling in Canada as it triggered a national discussion on the utility and uptake of modelling research in local and pandemic outbreaks. However, integration and application of model-based outcomes in public health requires knowledge translation and contextualization. We reviewed the history and performance of Pan-InfORM (Pandemic Influenza Outbreak Research Modelling), which created a national infrastructure in Canada with a mandate to develop innovative knowledge translation methodologies to inform policy makers through modelling frameworks that bridge the gaps between theory, policy, and practice. This review demonstrates the importance of a collaborative infrastructure as a “Community of Practice” to guide public health responses, especially in the context of emerging diseases with substantial uncertainty, such as the COVID-19 pandemic. Dedicated resources to modelling and knowledge translation activities can help create synergistic strategies at the global scale and optimize public health responses to protect at-risk populations and quell socioeconomic and health burden.     

Hybrid Approach to Estimation of Underreporting of Tuberculosis Case Notification in High-Burden Settings With Weak Surveillance Infrastructure: Design and Implementation of an Inventory Study

BackgroundThe greatest risk of infectious disease undernotification occurs in settings with limited capacity to detect it reliably. World Health Organization guidance on the measurement of misreporting is paradoxical, requiring robust, independent systems to assess surveillance rigor. Methods are needed to estimate undernotification in settings with incomplete, flawed, or weak surveillance systems. This study attempted to design a tuberculosis (TB) inventory study that balanced rigor with feasibility for high-need settings.ObjectiveThis study aims to design a hybrid TB inventory study for contexts without World Health Organization preconditions. We estimated the proportion of TB cases that were not reported to the Ministry of Health in 2015. The study sought to describe TB surveillance coverage and quality at different levels of TB care provision. Finally, we aimed to identify structural-, facility-, and provider-level barriers to notification and reasons for underreporting, nonreporting, and overreporting.MethodsRetrospective partial digitalization of paper-based surveillance and facility records preceded deterministic and probabilistic record linkage; a hybrid of health facilities and laboratory census with a stratified sampling of HFs with no capacity to notify leveraged a priori knowledge. Distinct extrapolation methods were applied to the sampled health facilities to estimate bacteriologically confirmed versus clinical TB. In-depth interviews and focus groups were used to identify causal factors responsible for undernotification and test the acceptability of remedies.ResultsThe hybrid approach proved viable and instructive. High-specificity verification of paper-based records in the field was efficient and had minimal errors. Limiting extrapolation to clinical cases improved precision. Probabilistic record linkage is computationally intensive, and the choice of software influences estimates. Record absence, decay, and overestimation of the private sector TB treatment behavior threaten validity, meriting mitigation. Data management demands were underestimated. Treatment success was modest in all sectors (R=37.9%–72.0%) and did not align with treatment success reported by the state (6665/8770, 75.99%). One-fifth of TB providers (36/178, 20%) were doubtful that the low volume of patients with TB treated in their facility merited mastery of the extensive TB notification forms and procedures.ConclusionsSubnational inventory studies can be rigorous, relevant, and efficient in countries that need them even in the absence of World Health Organization preconditions, if precautions are taken. The use of triangulation techniques, with minimal recourse to sampling and extrapolation, and the privileging of practical information needs of local decision makers yield reasonable misreporting estimates and viable policy recommendations.     

Confirmed Cases of Ophidiomycosis in Museum Specimens from as Early as 1945, United States

Ophidiomycosis represents a conservation threat to wild snake populations. The disease was reported in North America early in the 21st century, but the history of ophidiomycosis has not been investigated. We examined museum specimens and confirmed cases of ophidiomycosis >50 years before the disease’s reported emergence.     

EBV感染患儿临床特征及血清免疫因子水平

目的分析124例巴尔病毒(EBV)感染患儿的临床特征和血清免疫因子水平。方法选择2016年12月-2019年12月于海南医学院第一附属医院确诊的124例EBV感染患儿为研究组,根据临床表现分为传染性单核细胞增多症(IM)组43例和单纯性EBV组81例,选择同期健康体检儿童62名为对照组。记录所有患儿入组时的年龄、性别、临床症状;荧光定量PCR反应检测外周血淋巴细胞中EBV DNA载量;检测血清白细胞介素-6(IL-6)、IL-2和肿瘤坏死因子-α(TNF-α)水平,流式细胞仪分析外周血T淋巴细胞水平;Pearson相关性分析外周血T淋巴细胞亚群与EBV DNA载量之间的相关性。结果 IM组患儿的年龄为(5.13±1.56)岁,大于单纯性EBV组(P<0.05),出现发热、咽峡炎、淋巴结肿大、脾肿大、肝肿大、眼睑水肿、鼻塞、打鼾的比例为88.37%、93.02%、93.02%、48.84%、60.47%、32.56%、55.81%和46.51%,高于单纯性EBV组(P<0.05);IM组患儿的血CD3+T、CD8+T细胞、IL-6、TNF-α为分别为(73.25±7.16)%、(40.19±4.21)%、(33.68±5.71)ng/L、(72.52±11.26)ng/L高于对照组,而CD4+T、CD4+/CD8+T细胞、IL-2分别为(34.86±3.75)%、(0.89±0.15)、(10.43±3.38)ng/L则均低于对照组(P<0.05);外周血CD3+T和CD8+T细胞水平均与病毒载量呈正相关(r=0.314,0.447,P<0.05),CD4+T和CD4+/CD8+T细胞水平与病毒载量呈负相关(r=-0.425,-0.376,P<0.05)。结论 EBV感染患儿的临床症状和细胞免疫功能与病毒载量有关,有望应用于临床评估EBV感染的病情发展。     

新发传染病鉴定技术研究进展

近年来,人与野生动物日益频繁的接触,再加上病原微生物本身不断的变异和进化,导致新发传染病(emerging infectious diseases,EIDs)的发生呈持续增长态势,暴发频率不断增加,给全球公共卫生带来极大威胁与挑战。在下一次新发传染病暴发之际,希望能通过合理运用相关技术方法准确快速回答“病原体是什么”、“病原体来自哪”两大问题,从而及时有效预警并从源头控制新发传染病的大流行。对当前新发传染病病原体的鉴定技术进行归纳介绍,并探讨各种技术的优劣势以及各自应用领域。