浙江省2006年乙型流感病毒的分子变异和抗原特性研究

2006年浙江省乙型流感的流行强度明显较往年增强,为明确2006年浙江省乙型流感病毒流行株的分子进化特征,分析其发生暴发的原因,我们对当年从各地市分离的乙型流感病毒进行了抗原及基因特征分析,并与2005年分离毒株进行比较.     

Molecular epidemiology of influenza B virus and implications in immunization strategy,Southern Brazil

Epidemiological indicators have shown the substantial impact of influenza B (Flu B) on the development of severe acute respiratory infection (SARI) and on mortality rates. In Brazil, the trivalent vaccine, composed of only one Flu B lineage is available. We investigated Flu B infections in clinical samples collected by the epidemiological surveillance service of Paraná State, Brazil, from 2013 to 2016. The Flu B lineages Yamagata- (B/Yam) and Victoria-like (B/Vic) were identified using the qRT-PCR assay, and notification forms were reviewed. Among 379 Flu B positive samples evaluated, 370 (98%) were characterized as B/Yam or B/Vic lineages. Both co-circulated with a frequency of 47% and 53%, respectively. B/Yam infected equally both genders, while B/Vic was more frequent in females (71%). The median age of patients infected by B/Vic (23y; 11–35) was lower than that of patients infected by B/Yam (32y; 12–50). Mismatch between the vaccine and the circulating strain was observed in the 2013 season, with a high number of SARI cases. B/Vic lineage was associated with a larger number of SARI cases (62%), while B/Yam with influenza-like illness (ILI) (61%). Differences were observed in the strains circulating in separate regions of Paraná State. B/Vic was prevalent in the northwestern (67%) and B/Yam in the southeastern region (60%). The unpredictability of Flu B lineage circulation causes a substantial increase in severe disease during epidemics in a vaccine mismatch season. In addition, the differences in the epidemiological profile of the target population of Flu B infections in relation to other respiratory viruses, as well as among the B/Vic and B/Yam lineages may also be associated to an increase in disease burden. These findings have direct consequences on vaccination strategies. Therefore, further molecular epidemiology studies of Flu B in Brazil are required to corroborate these primary results.     

Molecular epidemiology of Norwalk-like virus (NLV) outbreaks occurring in Kyushu Japan between 1988 and 1993

In nine outbreaks that occurred in the Kyushu district between 1988 and 1993, we determined the nucleotide sequences of Norwalk-like virus (NLV) gene fragments amplified by RT-PCR and molecular-epidemiologically analyzed the NLV epidemics. It is known that the NLV strains isolated from nine outbreaks of acute gastroenteritis, were divided into five clusters consisting of two genogroups. Described by the year of outbreaks, the genogroup-1 (Norwalk-like virus group) was prevalent in 1988, 1989, and 1992, the genogroup-2 (snow mountain-like virus group) was detected in 1988, 1989, and 1993. Especially it was revealed that various strains of NLV were prevalent in the Kyushu district from 1988 to 1989. Epidemics of the Norwalk-like strain continued to be prevalent in 1992 (FP/7/92), and the strains very close to OSAP 18 continued to be prevalent in 1993 (FP/8/93, FP/9/93). Although the strains belonging to Norwalk virus (KY89) in the genogroup-1 and belonging to P1B (OSAP 18) in the genogroup-2 were detected for a prolonged period from 1988 to 1992/1993, the homology in these strains was very close, and this study shows that a high homogeneity was conserved in these strains. It was revealed that various strains of NLV were prevalent in the Kyushu district from 1988 to 1989.     

2006年河北省流感爆发中分离Victoria系乙型流感病毒变异株血凝素基因序列分析

目的研究2006年河北省流感爆发中分离的乙型流感毒株HA抗原性和基因特性,阐明HA基因的变异与流感爆发的关系。方法用MDCK细胞分离培养流感病毒,提取病毒核糖核酸,采用RT-PCR扩增病毒HA基因,纯化产物进行核苷酸序列测定,用DNAStar软件作分析处理。结果2006年在河北省流感爆发中分离的乙型流感病毒属Victoria系,与最近的代表株B/HongKong/330/2001相比已发生较大变异,核苷酸同源性仅为96.4%～96.8%,在抗原决定簇上有6～7个位点发生了氨基酸替换,与流感监测中分离的Victoria系乙型流感病毒HA1区改变一致。结论2006年河北省流感爆发与常规监测中分离到的乙型流感病毒HA1抗原性改变一致,是Victoria系乙型流感病毒的一个新变种,在HA1区域发生的变异是乙型流感爆发的主要原因,应引起重视。     

中国流感疫苗预防接种技术指南 (2022 — 2023)

  目的  采用检测阴性设计（TND）病例对照研究评价中小学生接种灭活三价流感疫苗的保护效果（VE）。  方法  对深圳市南山区2021年11月 — 2022年5月综合医院发热门诊发现的286例6～15岁中小学生流感样病例（ILI）进行流感病毒核酸PCR检测,流感病毒核酸检测阳性者为阳性病例组,检测阴性者为阴性对照组,收集2组的流感疫苗接种记录,计算2组的流感疫苗接种比值比（OR）及VE。  结果  286例ILI中,流感病毒核酸检测阳性68例（23.78%）,均为乙型流感,阴性218例（76.22%）,病例组当季流感疫苗接种率为5.88%（4/68）,对照组接种率为15.14%（33/218）,OR值为0.3886（95%CI = 0.1528～0.9880）,VE为61.14%（95%CI = 1.20%～84.72%）。  结论  接种当季流感疫苗可以保护中小学生感染流感,鼓励中小学生接种当季流感疫苗以预防流感。     

4起学校甲3型流感爆发疫情的流行特征及控制措施效果研究

目的对4起疫情较为严重的学校甲3型流感爆发疫情,分析研究其流行特征和不同控制措施效果,探讨科学有效的控制措施.方法采用回顾性调查和现况调查的流行病学调查方法收集资料,用Epi Info软件进行数据处理.对病人标本采用RT-PCR方法进行实验室快速诊断.结果4起甲3型流感爆发疫情罹患率分别为20.43%（D）、11.72%（C）、9.37%（A）和4.08%（B）,罹患率间差异有显著性.4起疫情分别发生在2月（A）、5月（B）、9月（C）和12月（D）,病例以15岁以下年龄人群为主,首发病例/指示病例所在班级病例较为集中.A、C、D 3起疫情报告不及时,C、D两起疫情对病人的隔离措施落实不彻底,A、B两起控制效果较好.结论2004年某省流感爆发疫情均为甲3型,提示甲3型流感病毒变异活跃,应开展该省流感监测毒株和爆发毒株的抗原性和基因特性研究.所有流感爆发疫情均发生在学校,学校流感的预防将是控制流感疫情的关键.责任报告单位及报告人的法制意识和疫情报告的敏感性亟待加强.     

Molecular epidemiology of influenza viruses: Memorandum from a WHO Meeting

This Memorandum summarizes recent information on influenza viruses of non-human hosts, discussed at the WHO Consultation on Molecular Epidemiology of Influenza Viruses, Athens, Georgia, USA, in September 1986. It was noted that a wide variety of antigenic variants of influenza viruses have been isolated from non-human hosts, especially birds. Of particular epidemiological interest in recent years has been the isolation of H7N7 influenza viruses from epidemics of disease in seals, the isolation of an H10N7 virus from outbreaks of disease among domestic mink, and the occurrence of pathogenic avian influenza viruses in Australia, Ireland and the USA.     

Molecular epidemiology of Serratia marcescens outbreaks in two neonatal intensive care units.

OBJECTIVE: Serratia marcescens can cause serious infections in patients in neonatal intensive care units (NICUs), including sepsis, pneumonia, urinary tract infection, and conjunctivitis. We report the utility of genetic fingerprinting to identify, investigate, and control two distinct outbreaks of S. marcescens. DESIGN: An epidemiologic investigation was performed to control two clusters of S. marcescens infections and to determine possible routes of transmission. Molecular typing by pulsed-field gel electrophoresis determined the relatedness of S. marcescens strains recovered from neonates, the environment, and the hands of healthcare workers (HCWs). SETTING: Two geographically distinct level III-IV NICUs (NICU A and NICU B) in two university-affiliated teaching hospitals in New York City. RESULTS: In NICU A, one major clone, "F," was detected among isolates recovered from four neonates and the hands of one HCW. A second predominant clone, "A," was recovered from four sink drains and one rectal surveillance culture from an asymptomatic neonate. In NICU B, four neonates were infected with clone "D," and three sink drains harbored clone "H." The attributable mortality rate from bloodstream infections was 60% (3 of 5 infants). The antimicrobial susceptibilities of clone F strains varied for amikacin, cefepime, and piperacillin/tazobactam. CONCLUSIONS: S. marcescens causes significant morbidity and mortality in preterm neonates. Cross-transmission via transient hand carriage of a HCW appeared to be the probable route of transmission in NICU A. Sinks did not harbor the outbreak strains. Antimicrobial susceptibility patterns did not prove to be an accurate predictor of strain relatedness for S. marcescens.     

Molecular epidemiology of hepatitis B virus in Paraguay

Hepatitis B virus (HBV) infection is a leading cause of severe chronic liver disease worldwide. The HBV epidemiology in Latin American countries is complex and the data is still scanty and fragmentary. The aim of this study was to investigate the distribution of HBV genotypes in Paraguay and to estimate the viral population dynamic and spread pattern of the main phylogenetic group. To this end, partial and complete genome sequences were obtained from 60 blood donor candidates and analysed by phylogenetic and Bayesian phylodynamic approaches.The phylogenetic analysis based on sequences of partial Polymerase/Pre-S1 overlapping region showed a predominance of the Native American subgenotype F4 (81.7%), the presence of the European subgenotypes A2 (1.7%) and D3 (8.3%), the African subgenotype A1 (3, 5%) and the Asian subgenotypes B2 (1.7%) and C2 (1.7%). The distribution of HBV genotypes was in accordance with the ethnic composition of the population.The phylogeographic analysis of subgenotype F4 complete genomes suggests that this lineage emerged and spread in the last 300 years. Paraguay was the most probable location of the common ancestor. The lineage diverged into two main clades and spread to neighbor regions, mainly Bolivia and Northwest Argentina, and Buenos Aires. The phylogeny showed a scanty geographical structure and a complex migratory pattern.In conclusion, the HBV genotypes circulating in Paraguay reflect the ethnic origin of the population. The distribution of genotypes and the phylogeographic reconstruction showed the impact of both global and local migrations in shaping the HBV molecular epidemiology in the region.     

Molecular epidemiology for local outbreaks of methicillin resistantStaphylococcus aureus (MRSA)

Subtyping isolates may be useful for epidemiological studies of methicillin-resistant-Staphylococcus aureus (MRSA) outbreaks. Among subtyping methods, DNA-based techniques have been applied very effectively for this purpose. An outbreak of MRSA infections took place in one hospital in Barcelona early during 1991. From the beginning of the outbreak to December 92, 70 MRSA isolates from different patients and sources were collected. All strains were evaluated by restriction endonuclease analysis of plasmid DNA (REAP) and macrorestriction endonuclease analysis of genomic DNA usingSma I and pulsed-field-gel-electrophoresis (PFGE). Plasmid screening and REAP usingHind III demonstrated two plasmid subtypes: subtype A showing a large plasmid, and subtype B showing the same large plasmid plus a smaller one. Subtypes A and B corresponded to the more recent and older isolates, respectively, suggesting the loss of the small plasmid during the epidemic. PFGE usingSma I displayed two closely related profiles (PFGE subtype A and A'; CS=0.90). These subtypes were different from those subtypes exhibited from 4 methicillin-susceptible-Staphylococcusaureus (MSSA) isolates from the same hospital and from 2 epidemiologically unrelated MRSA isolates. Almost all isolates showing PFGE subtype A preceded those isolates showing PFGE subtype A'. This fact and the similarity between both subtypes suggested minor chromosomal DNA rearrangement during the outbreak from a unique strain. While PFGE usingSma I is a useful tool in evaluation of clonal dissemination, our data suggest epidemic or local outbreaks may need several methods to best delineate the source and spread of MRSA strains. The reproducibility and discriminatory power of REAP makes it a useful adjunct in this context.     

浙江省2006-2007年暴发性胃肠炎中诺如病毒的分子流行病学分析

目的 分析浙江省2006-2007年暴发性病毒性胃肠炎中诺如病毒感染的分子流行病学特征.方法 收集监测期间暴发性病毒性胃肠炎疫情患者的粪便标本及相关流行病学资料.采用RT-PCR及荧光定量RT-PCR检测诺如病毒.随机选掸部分阳性标本扩增部分多聚酶区和衣壳蛋白片段,进行序列测定,结合诺如病毒I(GI)、Ⅱ(GⅡ)基因型参考株进行进化分析.结果 诺如病毒感染暴发性胃肠炎共5起,发生时间均集中于9-12月,送检标本63份,诺如病毒检测阳性45份.序列分析结果显示,浙江省诺如病毒序列与诺如病毒GⅡ/4型参考株同源性最高,其中与北京2006年、荷兰2006年诺如病毒GⅡ/4型变异株最为接近,核苷酸同源性分别为99.7%和98.5%～99.0%.诺如病毒与北京、荷兰流行的GⅡ/4型变异株处于同一分支.结论 诺如病毒是浙江省病毒性腹泻暴发疫情的重要病原体,流行时间集中于秋季,其流行株为GⅡ/4型变异病毒株.     

Concurrent outbreaks of influenza A and influenza B

During the winter of 1982 concurrent outbreaks of influenza A and influenza B occurred. The epidemiology and clinical features of 151 cases referred during this time are described, and patients are discussed according to age and presenting clinical syndrome: croup was the commonest presentation in young children, a typical influenza syndrome predominated in young adults, while older patients were more likely to have lower respiratory tract infection. There was no significant difference between the clinical features of influenza A and influenza B. Unusual clinical features include rash, exudative tonsillitis and the need for myringotomy during the course of influenza.     

Molecular epidemiology of Oropouche virus, Brazil

Oropouche virus (OROV) is the causative agent of Oropouche fever, an urban febrile arboviral disease widespread in South America, with >30 epidemics reported in Brazil and other Latin American countries during 1960-2009. To describe the molecular epidemiology of OROV, we analyzed the entire N gene sequences (small RNA) of 66 strains and 35 partial Gn (medium RNA) and large RNA gene sequences. Distinct patterns of OROV strain clustered according to N, Gn, and large gene sequences, which suggests that each RNA segment had a different evolutionary history and that the classification in genotypes must consider the genetic information for all genetic segments. Finally, time-scale analysis based on the N gene showed that OROV emerged in Brazil ≈223 years ago and that genotype I (based on N gene data) was responsible for the emergence of all other genotypes and for virus dispersal.     

Molecular epidemiology of Rift Valley fever virus

Phylogenetic relationships were examined for 198 Rift Valley fever virus isolates and 5 derived strains obtained from various sources in Saudi Arabia and 16 countries in Africa during a 67-year period (1944-2010). A maximum-likelihood tree prepared with sequence data for a 490-nt section of the Gn glycoprotein gene showed that 95 unique sequences sorted into 15 lineages. A 2010 isolate from a patient in South Africa potentially exposed to co-infection with live animal vaccine and wild virus was a reassortant. The potential influence of large-scale use of live animal vaccine on evolution of Rift Valley fever virus is discussed.     

2013 - 2017年贵州省流感暴发疫情特征分析

目的 分析贵州省2013 - 2017年流感暴发疫情的流行病学特征,为流感防控提供科学依据。方法 收集2013 - 2017年全省报告的流感暴发疫情资料,对疫情的时间、场所及实验室检测结果进行描述性流行病学分析。结果 从2013 - 2017年,贵州省累计报告流感暴发疫情149起,累计报告病例2 276例。主要由B型流感（46起）、季节性H3N2流感（38起）和甲型H1N1流感（29起）引起。暴发疫情主要集中在每年的冬春季（11 - 12月份）,发生场所为中小学校,报告116起（占92.8%）,疫情规模以10～29例的起数最多,共128起。累计报告最多的地区是贵阳市（59起）。结论 贵州省流感暴发疫情冬春季高发,场所主要集中在学校,流感病毒流行优势株在贵州省交替出现,应及时做好流感监测和预测预报。     

Concurrent outbreaks of influenza A and influenza B.

During the winter of 1982 concurrent outbreaks of influenza A and influenza B occurred. The epidemiology and clinical features of 151 cases referred during this time are described, and patients are discussed according to age and presenting clinical syndrome: croup was the commonest presentation in young children, a typical influenza syndrome predominated in young adults, while older patients were more likely to have lower respiratory tract infection. There was no significant difference between the clinical features of influenza A and influenza B. Unusual clinical features include rash, exudative tonsillitis and the need for myringotomy during the course of influenza.     

Molecular epidemiology of respiratory syncytial virus in The Gambia

Respiratory syncytial virus (RSV) infection in The Gambia occurs seasonally in association with the rainy season. This study examined the genetic variability of RSV isolates from four consecutive epidemics from 1993-6. Each epidemic was made up of a number of variants which were replaced in subsequent epidemics. Analysis of attachment (G) protein gene sequences showed that isolates were closely related to those observed in the rest of the world. However, many isolates from 1993 and 1994 were unlike other isolates observed in the developed world during this period and were more similar to isolates from 1984 in Europe. In addition, the most commonly observed genotype in the UK in the 1990s was not detected in The Gambia during this period.