惠州市流感病原学监测结果分析

目的对我市流感样病例标本进行病原学检测,分析其病原学特点,为流感防控提供病原学依据。方法采用MDCK细胞（狗肾细胞）培养法分离流感病毒,用血凝抑制试验对病毒株进行分型鉴定。结果从哨点医院采集的520份标本中共分离出流感病毒4l株,分离率为7．9％,以新甲型H1N1为主。其中新甲型H1N126株（63．4％）,H3N2型5株（12．2％）,B（Yamagata）型1株（2．4％）．B（Victoria）型9株（22．0％）。流感流行高峰出现在春季的1—3月和秋季的8-9月。健康人群血清中流感抗体的阳性率不高,最高为新甲型H1N1抗体阳性率41．9％,最低为B（Yamagata）的抗体阳性率,仅8．1％。对2010年2株新甲型H1N1进行基因测序,结果显示甲型H1N1基因未发生变异,暂时不会造成大的流行。结论惠州市流感病毒的流行时间有明显的季节性,活动相对平缓,新甲型H1N1流感病毒是春季的优势毒株,下半年逐渐转变为H3N2型流感病毒。     

Seasonal influenza activity based on laboratory surveillance in Malaysia, 2011-2016

Influenza seasonality in equatorial countries is little understood. Seasonal and alert influenza thresholds were determined for Malaysia, using laboratory-based data obtained from the Malaysia Influenza Surveillance System and a major teaching hospital, from 2011 to 2016. Influenza was present year-round, with no clear annual seasons. Variable periods of higher transmission occurred inconsistently, in November to December, January to March, July to September, or a combination of these. These coincide with seasons in the nearby southeast Asian countries or winter seasons of the northern and southern hemispheres. Changes in the predominant circulating influenza type were only sometimes associated with increased transmission. The data can provide public health interventions such as vaccines.     

Hospital‐based influenza surveillance in Korea: Hospital‐based influenza morbidity and mortality study group

Influenza epidemics occur annually with variations in size and severity. Hospital‐based Influenza Morbidity & Mortality was established to monitor influenza epidemics and their severity, which is composed of two surveillance systems: emergency room‐based and inpatient‐based surveillance. Regarding emergency room‐based surveillance, influenza‐like illness index (influenza‐like illness cases per 1,000 emergency room‐visiting subjects), number of laboratory‐confirmed cases and the distribution of influenza types were estimated weekly. Inpatient‐based surveillance included monitoring for hospitalization, complications, and mortality. The emergency room influenza‐like illness index correlated well with the number of laboratory‐confirmed influenza cases, and showed a bimodal peak at Week 4 (179.2/1,000 emergency room visits) and Weeks 13‐14 (169.6/1,000 emergency room visits) of 2012. Influenza A was the predominant strain during the first epidemic peak, while influenza B was isolated exclusively during the second peak. In 2011–2012 season, the mean admission rate of emergency room‐visiting patients with influenza‐like illness was 16.3% without any increase over the epidemic period. Among the hospitalized patients with influenza, 33.6% (41 out of 122 patients) were accompanied by complications, and pneumonia (28.7%, 35 out of 122 patients) was the most common. Most fatal cases were caused by influenza A (96.2%) after the first epidemic peak. In conclusion, Hospital‐based Influenza Morbidity & Mortality was effective for monitoring the trends in circulating influenza activity concurrently with its severity. In the 2011–2012 season, the influenza epidemic persisted for a ≥5‐month period, with a bimodal peak of influenza A and B in sequence. Overall, influenza A was more severe than influenza B. J. Med. Virol. 85:910–917, 2013. © 2013 Wiley Periodicals, Inc.     

北京市房山区2014-2015年流感病原学监测结果分析

目的 通过对北京市房山区2014-2015年流感病原学的监测结果进行分析,了解房山区流感病毒的流行特征.方法 采集房山区哨点医院流感样病例的咽拭子标本1 339份,用荧光定量PCR法检测核酸及亚型,同时进行流感病毒分离及血凝实验(HA)检测.结果 2014年1月6日-2015年12月28日,共采集1 339份流感样病例咽拭子,荧光定量PCR法检测核酸阳性数为215例(阳性率为16.06％),其中甲型H1N1流感病毒32株,甲型H3N2流感病毒107株,乙型流感病毒76株.病毒分离阳性数为148例(阳性分离率为11.05％).本年度第2-6周和第48-52周流感阳性率较高,且第2-6周以甲型H1N1和乙型流感病毒为主,第48-52周以甲型H3N2流感病毒为主.结论 房山区2014-2015年流感高发季节为第2-6周和第48-52周,上半年致病病原体以甲型HIN1流感病毒和乙型流感病毒为主,下半年以H3N2流感病毒为主,不同性别之间各亚型流感病毒的阳性率构成比无统计学差异(P＞ 0.05).     

Molecular characterization of influenza viruses circulating in Northern Italy during two seasons (2005/2006 and 2006/2007) of low influenza activity

The influenza activity and circulation of influenza viruses in Lombardy (the most populous Italian region) were observed during two consecutive seasons (2005/2006 and 2006/2007) characterized by low influenza activity by the Italian Influenza Surveillance Network. The molecular characteristics of circulating viruses were analyzed to evaluate the introduction of new variants and emergence of vaccine-escape viruses. In both seasons, the epidemic in Lombardy was sustained almost exclusively by influenza A viruses, accounting for 80.5% and 93.6% of total detections, respectively, and the co-circulation of A/H3 viruses belonging to distinct phylogenetic groups was observed. The A/H1N1 viruses isolated during the 2005/2006 season were closely related to A/New Caledonia/20/99, while the hemagglutinin (HA) sequences of the A/H1N1 viruses from the 2006/2007 season exhibited a greater diversity. These viruses were A/Solomon Islands/3/2006-like and showed several variants. All B isolates were similar to B/Malaysia/2506/2004 belonging to the B/Victoria/2/87-lineage. Influenza B virus was the dominant virus in Europe in the 2005/2006 season and accounted for the 20% of total detections in Lombardy. Overall, the viruses studied presented heterogeneity in their HA sequences suggesting the circulation of a miscellaneous set of variants during the two seasons notwithstanding the medium-low activity of influenza. The importance of virological surveillance of influenza viruses is recognized widely and the molecular characterization of the viruses, especially in vaccinated subjects, is of particular importance to evaluate the introduction and circulation of new variants.     

Genetic and antigenic analysis of epidemic influenza viruses isolated during 2006-2007 season in Taiwan

Influenza viruses are some of the most active pathogens in Taiwan. The monitoring influenza activity has been coordinated by the Centers for Diseases Control, Taiwan, and the surveillance is based on integrated clinical and virological surveillance components. Data from sentinel physician networks and other sources, mainly hospitals were collected. During 2006-07 season, a total of 1724 cases of laboratory-confirmed influenza were reported by collaborating laboratories and sentinels, which was five fold higher than during the corresponding part of the 2005-06 season. Of the Taiwan isolates analyzed using post-infection ferret antisera, 1.5% were H1N1 (A/Hi), 21.5% H3N2 (A/H3), and 77.0% influenza B viruses. This reflects the predominance of influenza B viruses during 2006-07 season. In addition, continued antigenic drift was seen with the A/I-B viruses compared with the previous season's reference strains. However, an increasing number of recent A/H3 isolates characterized in our report were amantadine sensitive. Preparation for an influenza pandemic is presently a high priority in Taiwan. Laboratory-based surveillance systems must be timely in order to be effective. The data presented here highlights the need to characterize the circulating strains both antigenically and genetically during regular surveillance. Any contribution of individual genes or gene combinations to usual or unusual epidemic characteristics might thus be identified ensuring that virus strains can be selected for vaccine formulation that will most closely match the circulating viruses.     

Active virological surveillance in backyard ducks in Bangladesh: detection of avian influenza and gammacoronaviruses

ABSTRACT

Domestic waterfowl play an important role in the perpetuation and transmission of avian pathogens including avian influenza viruses (AIV) of low and high pathogenicity, which pose severe economic and public health concerns in Bangladesh. This study focused on active surveillance of several avian viral pathogens with a special reference to AIV in selected backyard duck populations in Bangladesh. A total of 500 pooled oropharyngeal and cloacal samples from individual ducks of four districts were tested by real time PCRs for the presence of AIV, avian avulavirus-1, anatid herpesvirus-1, avian parvovirus, avian bornavirus and avian coronavirus. The investigation identified 27 (5.4%) ducks positive for AIV and 12 (2.4%) positive for avian coronavirus. In 13 samples, RNA specific for AIV H4N6 was detected. Phylogenetic analysis of the AIV haemagglutinin H4 and neuraminidase N6 genes suggested a clustering of Bangladeshi AIV H4N6 in Eurasian lineage group 2. Other AIV positive samples had very low virus loads (Cq?>?36) and were not subtyped. Coronaviral sequences of a fragment of the polymerase gene were related to Eurasian-Australian duck gamma-coronaviruses. Our current active surveillance in free-range domestic backyard ducks in Bangladesh failed to detect highly pathogenic (HP) AIV in contrast to our previous passive monitoring study. Nevertheless, active monitoring of domestic duck populations may be important to highlight presence and transmission dynamics of economically less important AIV that still may serve as reassortment partners for the generation of new HP and zoonotic AIV.

RESEARCH HIGHLIGHTS

• Active surveillance for viral pathogens in domestic free-range backyard ducks.

• Detection of avian influenza virus subtype H4N6.

• First identification of avian gammacoronavirus in ducks in Bangladesh.

     

实时荧光定量PCR在铁路运输动物携带甲型流感病毒检测中的应用

目的探讨应用实时荧光PCR对铁路运输动物携带甲型流感病毒进行快速检测的可行性,为制定铁路系统有效的流感监测方案奠定基础。方法采集死禽咽喉部和泄殖腔拭子,活体动物用拭子涂抹泄殖腔外周,粪便和毛用拭子涂抹表面。依据《全国流感监测实施方案》、甲型流感病毒核酸检测试剂盒（PCR-荧光探针法）说明书以及ABI7500F型实时荧光定量PCR的SDS软件操作。结果共采集广州中铁快运货场动物样本250份,检出甲型流感病毒核酸阳性11份,阳性率4.4%,其中以鸽类样本的阳性检出率最高,鹅次之,鸭最低。结论实时荧光PCR检测方法适合铁路运输的实际要求,结合进一步病毒分型和病毒基因测序,对掌握病毒流行趋势,做好预防控制工作具有重要意义。     

Increased cases of influenza C virus in children and adults in Austria, 2022

Sentinel surveillance of influenza-like illnesses revealed an increase in the cases of influenza C virus in children and adults in Austria, 2022, compared to previous years, following one season (2020/2021), wherein no influenza C virus was detected. Whole-genome sequencing revealed no obvious genetic basis for the increase. We propose that the reemergence is explained by waning immunity from lack of community exposure due to restrictions intended to limit severe acute respiratory syndrome coronavirus 2 spread in prior seasons, pending further investigation.     

Real-time PCR and its application to mumps rapid diagnosis

A real-time polymerase chain reaction assay was initially developed in China to detect mumps genome. The primers and TaqMan-MGB probe were selected from regions of the hemagglutinin gene of mumps virus. The primers and probe for the real-time PCR were evaluated by both laboratories in China and in the UK using three different pieces of equipment, LightCycler (Roche), MJ DNA Engine Option 2 (BIO-RAD) and TaqMan (ABI Prism) on different samples. The reaction was performed with either a one-step (China) or two-step (UK) process. The sensitivity (10 copies) was estimated using a serial dilution of constructed mumps-plasmid DNA and a linear standard curve was obtained between 10 and 10(7) DNA copies/reaction, which can be used to quantify viral loads. The detection limit on cell culture-grown virus was approximately 2 pfu/ml with a two-step assay on TaqMan, which was equivalent to the sensitivity of the nested PCR routinely used in the UK. The specificity was proved by testing a range of respiratory viruses and several genotypes of mumps strains. The concentration of primers and probe is 22 pmol and 6.25 or 7 pmol respectively for a 25 microl reaction. The assay took 3 hr from viral RNA extraction to complete the detection using any of the three pieces of equipment. Three hundred forty-one (35 in China and 306 in the UK) clinical specimens were tested, the results showing that this real-time PCR assay is suitable for rapid and accurate detection of mumps virus RNA in various types of clinical specimens.     

Severe seasonal influenza in ferrets correlates with reduced interferon and increased IL-6 induction

Even though ferrets are one of the principal animal models for influenza pathogenesis, the lack of suitable immunological reagents has so far limited their use in host response studies. Using recently established real-time PCR assays for a panel of ferret cytokines, we analyzed the local ferret immune response to human influenza isolates of the H1N1 and H3N2 subtypes that varied in their virulence. We observed that the severity of clinical signs correlated with gross- and histopathological changes in the lungs and was subtype-independent. Strains causing a mild disease were associated with a strong and rapid innate response and upregulation of IL-8, while severe infections were characterized by a lesser induction of type I and II interferons and strong IL-6 upregulation. These findings suggest that more virulent strains may interfere more efficiently with the host response at early disease stages.     

Seasonal influenza activity in Hong Kong and its association with meteorological variations

Influenza seasons appear consistently in the temperate regions, but are more variable in tropical/subtropical regions. The determinant for such variation remains poorly understood. This study documented the activity of influenza over a 10‐year period in Hong Kong; examining its association with changes in temperature and relative humidity. The two types of influenza exhibited different correlations with meteorological variations. Influenza A showed two seasonal peaks occurring respectively in winter/spring and summer months in most years. Influenza B showed a clear winter/spring peak, but its activity during summer months was more variable. Cold and humid conditions were associated with a higher activity of both influenza A and B. In contrast, hot and humid conditions were associated with a higher activity of influenza A, but were associated with only a moderate, less consistent increase in the activity of influenza B. A trend of increase in the magnitude of summer peaks of influenza A, but not influenza B, was observed. A hypothetical 2°C rise in temperature would decrease the proportion of favorable days for influenza A in December–April from 78% to 57%, but an increase from 58% to 71% in May–November; with a similar effect (from 83% to 62%) for influenza B during December–April, but a modest change (from 17% to 18%) during May–November. The presence of two seasonal peaks of influenza annually emphasizes the need to evaluate the duration of protective immunity offered by vaccination. Further study on the effects of climate change and global warming on the activity of influenza is warranted. J. Med. Virol. 81:1797–1806, 2009. © 2009 Wiley‐Liss, Inc.     

重组H9N2禽流感病毒的构建及其在不同细胞中的复制特性

目的利用反向遗传学技术构建具有感染性的H9N2亚型禽流感病毒,并揭示其在不同细胞中的复制特性。方法以A/Quail/Hong Kong/G1/97(H9N2)禽流感病毒基因组RNA为模板,用RT-PCR技术获得该病毒的8条完整基因片段,并分别将它们插入到p HW2000载体上,最终在293T细胞中包装产生重组H9N2病毒。并将重组的H9N2病毒感染不同细胞,观察病毒在不同细胞上的增殖状况来揭示该病毒在不同细胞上的复制特性。结果应用流感病毒8质粒反向遗传学技术,成功获得重组病毒,并揭示了该毒株在不同细胞(A549,MDCK,Vero)中的复制特性,发现A549人肺腺癌细胞更适宜H9N2病毒的正常复制。此外还分析总结了该毒株的与病毒毒力相关的重要位点特征。结论成功建立了H9N2禽流感病毒的反向遗传系统,该系统的建立为在分子水平研究H9N2病毒以及制备H9N2禽流感疫苗提供了依据。     

Local and peripheral cell-mediated immune response to influenza virus in mice

Presentation of different influenza virus antigens generates different immune responses. Intranasal immunization with either live (VA) or formalin-inactivated (VF) A/PR/8/34 (HON1) influenza virus induced local as well as peripheral cell-mediated immune response (CMI), as evidenced by elevation in 3H-thymidine incorporation. Cell-mediated immune response was detected as soon as 24-48 hr following the application of VA and 4-5 days following VF. Cell-mediated immune response in both instances peaked on the 12th day and disappeared between 16 and 20 days after application. Local CMI response was threefold higher after immunization with VA (SI = 28.6) than with VF (SI = 9.4), while VF induced higher peripheral response (32.0 vs 17.7). The mononuclear cell population in the lungs increased, correlating with a rise in the stimulation index (SI). The percentage of IgA surface-bearing B lymphocytes was significantly higher following IN administration of VA, but not following VF instillation. This corroborated the finding that VF failed to induce local antibody response in the lungs in spite of its capacity to stimulate humoral antibody and CMI responses. Mice immunized intramuscularly with both viral preparations developed a fair humoral antibody response without detectable CMI (peripheral or local).     

Serological responses in volunteers to inactivated trivalent subunit influenza vaccine: antibody reactivity with epidemic influenza A and B strains and evidence of a rapid immune response

A study of the immunogenicity of the inactivated trivalent subunit influenza vaccine for the 1989/90 season was performed in what proved to be an influenza epidemic year. One hundred student volunteers at The London Hospital Medical College participated in the study and the findings indicated that there was an excellent serological match between the epidemic strain of influenza A (H3N2) and the vaccine strain. Before vaccination, the geometric mean titre (GMT) to A/England/308/89, a representative H3N2 epidemic strain in the United Kingdom from the 1989/90 season, was 46. Post-vaccination the antibody levels rose and 99% of vaccinees had HI titres of greater than or equal to 40, the GMT being 131. The serological responses were also investigated against other circulating influenza A (H3N2 and H1N1) and B strains. Preliminary results of an evaluation of the rapidity of the immune response showed that in three of six subjects rises in HI antibody appeared within two days of vaccination.     

Development of a web-based survey for monitoring daily health and its application in an epidemiological survey

Background

Early detection of symptoms arising from exposure to pathogens, harmful substances, or environmental changes is required for timely intervention. The administration of Web-based questionnaires is a potential method for collecting information from a sample population.

Objective

The objective of our study was to develop a Web-based daily questionnaire for health (WDQH) for symptomatic surveillance.

Methods

We adopted two different survey methods to develop the WDQH: an Internet panel survey, which included participants already registered with an Internet survey company, and the Tokyo Consumers’ Co-operative Union (TCCU) Internet survey, in cooperation with the Japanese Consumers’ Co-operative Union, which recruited participants by website advertising. The Internet panel survey participants were given a fee every day for providing answers, and the survey was repeated twice with modified surveys and collection methods: Internet Panel Survey I was conducted every day, and Internet Panel Survey II was conducted every 3 days to reduce costs. We examined whether the survey remained valid by reporting health conditions on day 1 over a 3-day period, and whether the response rate would vary among groups with different incentives. In the TCCU survey, participants were given a fee only for initially registering, and health information was provided in return for survey completion. The WDQH included the demographic details of participants and prompted them to answer questions about the presence of various symptoms by email. Health information collected by the WDQH was then used for the syndromic surveillance of infection.

Results

Response rates averaged 47.3% for Internet Panel Survey I, 42.7% for Internet Panel Survey II, and 40.1% for the TCCU survey. During a seasonal influenza epidemic, the WDQH detected a rapid increase in the number of participants with fever through the early aberration reporting system.

Conclusions

We developed a health observation method based on self-reporting by participants via the Internet. We validated the usefulness of the WDQH by its practical use in syndromic surveillance.