H7N9 avian influenza with first manifestation of occipital neuralgia:A case report

BACKGROUND Most of the first symptoms of avian influenza are respiratory symptoms,and cases with occipital neuralgia as the first manifestation are rarely reported.CASE SUMMARY A middle-aged patient complaining of paroxysmal pain behind the ear was admitted to our hospital.The patient’s condition changed rapidly,and high fever,unexpected respiratory failure,and multiple organ failure developed rapidly.The patient was diagnosed with H7N9 avian influenza based on etiology.CONCLUSION We believe that the etiology of occipital neuralgia is complex and could be the earliest manifestation of severe diseases.The possibility of an infectious disease should be considered when occipital neuralgia is accompanied by fever.Avian influenza is one of these causative agents.

Inflammatory pseudotumors in the liver associated with influenza:A case report

BACKGROUND Inflammatory pseudotumor(IPT)is a rare and benign lesion that mimics malignancy and can develop in any part of the body.The pathophysiology and etiology of these quasineoplastic lesions remain unclear.CASE SUMMARY We report a case of a 65-year-old male who presented with fevers,night sweats,and unintentional weight loss following an influenza infection and was found to have multiple hepatic IPT’s following an extensive work up.CONCLUSION Our case highlights the importance of considering hepatic IPT’s in the differential in a patient who presents with symptoms and imaging findings mimicking malignancy shortly following a viral infection.

Erxian decoction potentially prevents postmenopausal osteoporosis by modulating miR-335: a study based on bioinformatics analysis and preliminary clinical case validation

Background:miRNAs are closely related to bone metabolism.Studies have shown that Erxian decoction can improve bone metabolism,possibly achieving this regulatory effect through miRNA targets.Netinfer was used to predict the miRNA targets of Erxian decoction for the treatment of postmenopausal osteoporosis,and the results were validated by clinical trials.Methods:In this study,we identified possible targets of Erxian decoction in osteoporosis by means of network pharmacological analysis and bioinformatic prediction.Fifteen cases of postmenopausal osteoporosis with kidney Yin and Yang deficiency(In traditional Chinese medicine,kidney Yin nourishes and moistens the tissues of the internal organs of the body,while kidney Yang promotes and warms the tissues of the internal organs of the body.)were treated with Erxian decoction for four weeks,and serum bone metabolism indices(P1NP,osteocalcin,andβ-CTX)and miRNA-335-5p expression were measured before and after treatment.Results:The constructed miRNA postmenopausal osteoporosis related gene network of the effective compound of the Erxian decoction has 296 points and 981 edges.The 39 postmenopausal osteoporosis related genes regulated by miRNA-335-5p were enriched in ossification,while the signaling pathways were enriched in rheumatoid arthritis,the Toll signaling pathway,the HIF-1 signaling pathway,and the MAPK signaling pathway.After taking Erxian decoction,the expression of the serum bone formation index(P1NP,osteocalcin)and miRNA-335-5p gene expression levels increased significantly.The alterations in P1NP and osteocalcin were correlated with the changes in miRNA-335-5p.Conclusion:Circulating miRNA-335-5p may serve as an important target of Erxian decoction in the treatment of postmenopausal women.The effect of Erxian decoction on bone formation is significant,but the underlying mechanism requires further investigation.

Creutzfeldt-Jakob disease presenting as Korsakoff syndrome caused by E196A mutation in PRNP gene:A case report

BACKGROUND Prion diseases are a group of degenerative nerve diseases that are caused by infectious prion proteins or gene mutations.In humans,prion diseases result from mutations in the prion protein gene(PRNP).Only a limited number of cases involving a specific PRNP mutation at codon 196(E196A)have been reported.The coexistence of Korsakoff syndrome in patients with Creutzfeldt-Jakob disease(CJD)caused by E196A mutation has not been documented in the existing literature.CASE SUMMARY A 61-year-old Chinese man initially presented with Korsakoff syndrome,followed by rapid-onset dementia,visual hallucinations,akinetic mutism,myoclonus,and hyperthermia.The patient had no significant personal or familial medical history.Magnetic resonance imaging of the brain revealed extensive hyperintense signals in the cortex,while positron emission tomography/computed tomography showed a diffuse reduction in cerebral cortex metabolism.Routine biochemical and microorganism testing of the cerebrospinal fluid(CSF)yielded normal results.Tests for thyroid function,human immunodeficiency virus,syphilis,vitamin B1 and B12 levels,and autoimmune rheumatic disorders were normal.Blood and CSF tests for autoimmune encephalitis and autoantibody-associated paraneoplastic syndrome yielded negative results.A test for 14-3-3 protein in the CSF yielded negative results.Whole-genome sequencing revealed a diseasecausing mutation in PRNP.The patient succumbed to the illness 11 months after the initial symptom onset.CONCLUSION Korsakoff syndrome,typically associated with alcohol intoxication,also manifests in CJD patients.Individuals with CJD along with PRNP E196A mutation may present with Korsakoff syndrome.

Epidemiology of fatal cases associated with pandemic influenza reported in Yemen

Objectives: This study describes the incidence of all fatal cases associated with Pandemic Influenza A (H1N1) in Yemen. It sets out to highlight the factors associated with poor prognosis *The authors declare that they have no competing interests. to enhance the implementation of prevention and control programs. Methods: The study is based on retrospective analysis of available data until 14 March 2010, as compiled by the disease control and surveillance team in Yemen. Results: Between 16 June 2009 and 14 March 2010, a total of 33 laboratory-confirmed death cases associated with pandemic influenza A (H1N1) were reported to the Diseases Control and Surveillance in the Ministry of Public Health and Population. During this period, a total of 6049 suspected influenza A (H1N1) cases were recorded. With this denominator, the case fatality rate (CFR) was 0.54%. During June through August, H1N1 confirmed cases were infrequently detected, including only 30;however, from September through December, over 200 confirmed cases were reported each month. Of the 33 cases recorded, 25 were male (76%) and 8 were female (24%), male to female ratio being 3:1. Overall median age of the death cases was 30.8 years (range 1 - 55). The most common diagnosis upon admission was pneumonia. Out of the deaths, twenty five (75.8%) had no documented underlying diseases. Chronic cardiovascular disease (9.1%) was the most commonly reported disease and 2 deaths (6.1%) were recorded as pregnant women. Conclusions: The most common diagnosis upon admission was pneumonia. Chronic cardiovascular diseases were the most commonly reported underlying conditions, while the most identified risk factor was pregnancy. These findings should be taken into consideration, when vaccination strategies are employed.

Severe community-acquired pneumonia caused by Leptospira interrogans:A case report and review of literature

BACKGROUND Leptospira is an uncommon pathogen for adult severe community-acquired pneumonia and its nonspecific manifestations and limited diagnostic tests make it difficult to identify.Although conventional penicillin remains efficacious to treat leptospirosis,failure in early diagnosis and treatment can lead to progression into a deadly syndrome with multiple organ dysfunction.Next generation sequencing is of great value to understand cases with infection of unknown cause,which could help in the diagnosis of uncertain Leptospira infection.CASE SUMMARY We recently managed a patient with fever,cough and dyspnea on admission that progressed into persistent adult respiratory distress syndrome,hemoptysis and hematuria after admission.In this case,the rare Leptospira infection was clouded by the positive influenza tests at admission,delaying early Leptospira-targeted antibiotics administration.Next generation sequencing,a novel molecular diagnostic tool,provided a key hint to uncover the crucial pathogen,Leptospira interrogans,further supported by the possible occupational exposure history.Subsequent conventional penicillin and mechanical respiratory support were administrated to cure the patient successfully without any sequela.CONCLUSION Clinicians must pay attention to possible exposure history and keep uncommon Leptospira in mind when managing pneumonia with unknown causes.

Distribution of Avian Influenza A Viruses in Poultry-Related Environment and Its Association with Human Infection in Henan, 2016 to 2017

Objective To survey avian influenza A viruses(AIVs) in the environment and explore the reasons for the surge in human H7 N9 cases.Methods A total of 1,045 samples were collected from routine surveillance on poultry-related environments and 307 samples from human H7 N9 cases-exposed environments in Henan from 2016 to2017. The nucleic acids of influenza A(Flu A), H5, H7, and H9 subtypes were detected by real-time polymerase chain reaction.Results A total of 27 H7 N9 cases were confirmed in Henan from 2016 to 2017, 24 had a history of live poultry exposure, and 15 had H7 N9 virus detected in the related live poultry markets(LPMs). About 96%(264/275) Flu A positive-environmental samples were from LPMs. H9 was the main AIV subtype(10.05%) from routine surveillance sites with only 1 H7-positive sample, whereas 21.17% samples were H7-positive in H7 N9 cases-exposed environments. Samples from H7 N9 cases-exposed LPMs(47.56%)had much higher AIVs positive rates than those from routine surveillance sites(12.34%). The H7+H9 combination of mixed infection was 78.18%(43/55) of H7-positive samples and 41.34%(43/104) of H9-positive samples.Conclusion The contamination status of AIVs in poultry-related environments is closely associated with the incidence of human infection caused by AIVs. Therefore, systematic surveillance of AIVs in LPMs in China is essential for the detection of novel reassortant viruses and their potential for interspecies transmission.

Cross-neutralizing Anti-hemagglutinin Antibodies Isolated from Patients Infected with Avian Influenza A(H5N1) Virus

Objective To recover broad-neutralizing monoclonal antibodies(Bn Abs)from avian influenza A(H5N1)virus infection cases and investigate their genetic and functional features.Methods We screened the Abs repertoires of expanded B cells circulating in the peripheral blood of H5N1 patients.The genetic basis,biological functions,and epitopes of the obtained Bn Abs were assessed and modeled.Results Two Bn Abs,2-12 D5,and 3-37 G7.1,were respectively obtained from two human H5N1 cases on days 12 and 21 after disease onset.Both Abs demonstrated cross-neutralizing and Ab-dependent cellular cytotoxicity(ADCC)activity.Albeit derived from distinct Ab lineages,i.e.,V^H1-69-D2-15-JH^4(2-12D5)and V^H1-2-D3-9-JH^5(3-32 G7.1),the Bn Abs were directed toward CR6261-like epitopes in the HA stem,and HA2 I45 in the hydrophobic pocket was the critical residue for their binding.Signature motifs for binding with the HA stem,namely,IFY in VH1-69-encoded Abs and LXYFXW in D3-9-encoded Abs,were also observed in 2-12D5 and 3-32 G7.1,respectively.Conclusions Cross-reactive B cells of different germline origins could be activated and re-circulated by avian influenza virus.The HA stem epitopes targeted by the Bn Abs,and the two Ab-encoding genes usage implied the VH1-69 and D3-9 are the ideal candidates triggered by influenza virus for vaccine development.

17α-hydroxylase/17,20 carbon chain lyase deficiency caused by p.Tyr329fs homozygous mutation:Three case reports

p.Tyr329fs is a cytochrome P450c17 mutation among Chinese individuals.However,data on 17-α-hydroxylase deficiency caused by cytochrome P450c17 p.Tyr329fs homozygous mutation are lacking.This paper is a case report of three patients homozygous for p.Tyr329fs who were diagnosed with 17-α-hydroxylase deficiency between 2005 and 2019.CASE SUMMARY Case 1 presented with hypertension,hypokalemia,sexual infantilism and delayed bone age.The patient had a 46,XY karyotype,was homozygous for p.Tyr329fs and was recently treated with dexamethasone 0.375 mg qn.Case 2 presented with hypokalemia,sexual infantilism,osteoporosis and delayed bone age.The patient had a 46,XY karyotype,was homozygous for p.Tyr329fs and was treated with dexamethasone 0.75 mg qn at the last follow-up.Serum potassium and blood pressure could be maintained within normal range for cases 1 and 2.Case 3 presented with amenorrhea,sexual infantilism,osteopenia and delayed bone age.The patient had a 46,XX karyotype,was homozygous for p.Tyr329fs and was treated with dexamethasone 0.75 mg qn and progynova 1 mg qd.Outpatient follow-up revealed an adrenocorticotropic hormone(8 AM)of<5.00 pg/mL.CONCLUSION The homozygous p.Tyr329fs mutation usually manifests as a combined deficiency,and definitive diagnosis depends primarily on genetic testing.

Superior mesenteric vein thrombosis induced by influenza infection:A case report

BACKGROUND Among the various types and causes of mesenteric ischemia,superior mesenteric vein(SMV)thrombosis is a rare and ambiguous disease.If a patient presents with SMV thrombosis,past medical history should be reviewed,and the patient should be screened for underlying disease.SMV thrombosis may also occur due to systemic infection.In this report,we describe a case of SMV thrombosis complicated by influenza B infection.CASE SUMMARY A 64-year-old male visited the hospital with general weakness,muscle aches,fever,and abdominal pain.The patient underwent computed tomography(CT)and was diagnosed with SMV thrombosis.Since the patient’s muscle pain and fever could not be explained by the SMV thrombosis,the clinician performed a test for influenza,which produced a positive result for influenza B.The patient had a thrombus in the SMV only,with no invasion of the portal or splenic veins,and was clinically stable.Anticoagulation treatment was prescribed without surgery or other procedures.The follow-up CT scan showed improvement,and the patient was subsequently discharged with continued oral anticoagulant treatment.CONCLUSION This case provides evidence that influenza may be a possible risk factor for SMV thrombosis.If unexplained abdominal pain is accompanied by an influenza infection,examination of an abdominal CT scan may be necessary to screen for possible SMV thrombosis.

Laninamivir-induced ischemic enterocolitis:A case report

BACKGROUND Neuraminidase inhibitor-associated acute hemorrhagic colitis is rare.We report a case of ischemic enterocolitis that was likely caused by laninamivir.CASE SUMMARY A 54-year-old female patient with influenza type A was administered 40 mg of laninamivir via inhalation once.On the same day,the patient experienced bloody stools and lower abdominal pain.A contrast-enhanced abdominal computed tomography showed edema-like changes from the descending colon to the sigmoid colon,which suggested ischemic enterocolitis.CONCLUSION We treated a patient with ischemic enterocolitis caused by laninamivir,a rare but similar symptom following the administration of oseltamivir.

Wells’syndrome possibly caused by hematologic malignancy,influenza vaccination or ibrutinib:A case report

BACKGROUND Wells’ syndrome(eosinophilic cellulitis) is an uncommon eosinophilic dermatosis of uncertain pathogenesis,characterized by clinical polymorphism and suggestive but nonspecific histopathologic traits.Its course is recurrent,and response to therapy is unpredictable.In a case in which the patient has a number of potential triggers for the manifestation of Wells’ syndrome skin rash,the treating physician must decide or must make an assumption in order to establish the most likely clinical scenario.This is important for the patient’s future treatment plans.CASE SUMMARY We describe the clinical case of a 46-year-old female with chronic lymphocytic leukemia who had already received treatment for several months with ibrutinib.She was diagnosed with Wells’ syndrome 10 d after an influenza vaccination containing thimerosal.Based on the literature,the patient was treated with a course of oral steroids.Resolution of clinical symptoms and rash were observed in response to the treatment.Ibrutinib was not discontinued.CONCLUSION The etiology of Wells’ syndrome remains unknown.Clinically,it resembles bacterial cellulitis.Lack of response to antibiotic treatment should lead the physician to consider a diagnosis of Wells’ syndrome.Treating the underlying condition is important and may lead to resolution of the syndrome.However,the most common and effective treatment to limit the course of the disease are systemic steroids.

Nasopharyngeal colonization of otopathogens in South Indian children with acuteotitis media -- A case control pilot study

Background: Acute otitis media (AOM) is an inflammatory disease of the middle ear causing significantmorbidity in early childhood. A pilot study was undertaken to identify the role of various risk factorsSouth Indian children with AOM, especially the role of nasopharyngeal otopathogens.Methodology: A prospective case control pilot study was conducted in children aged below six years,presenting to a single tertiary care from 2018 to 2019. Fifty cases with AOM and 45 age and gendermatched controls were recruited. Two nasopharyngeal swabs were collected, one was processed forbacterial culture. The other swab was processed according to the CDC recommended broth enrichmentmethod to identify carriage of S. pneumoniae. Subsequent serotyping was done by Quellung method andconventional sequential multiplex PCR.Result: Otalgia was the major presentation seen in 92% of the children with AOM. None of the clinical anddemographic characteristics were found to be statistically significant between the cases and controls. Themost common otopathogen was S. pneumoniae (55%) followed by H. influenza (29%). The commonS. pneumoniae serotypes encountered were 11A and 19F.Nasopharyngeal colonization with S. pneumoniae[OR 6.57, p < 0.003] and H. influenzae [OR14.18, p < 0.003] were significant risk factors for AOM inchildren. The risk increased with co-colonization (OR 13.89,p < 0.003).Conclusion: This study strengthens the significant association between nasopharyngeal colonization ofotopathogens and AOM as a risk factor that is enhanced by co-colonization.S. pneumoniae was the mainotopathogen in this population, serotypes 11A and 19F being the most common.

2017-2022年北京市西城区流感样病例特征分析

目的分析2017-2022年北京市西城区流感样病例特征,为制定流感防控策略提供依据。方法本研究为回顾性研究,研究对象为2017-2022年北京市西城区38家医疗机构通过北京市医院传染病监测预警系统上报的流感样病例,分析不同季度、不同等级医院流感样病例流行特征,采用时间序列拟合度模型分析流感样病例随时间变化的短期趋势。结果2017-2022年报告的51039581例门/急诊病例中监测到860926例流感样病例,流行高峰在12月至次年1月。2020-2022年组流感样病例百分比低于2017-2019年组,差异有统计学意义(χ^(2)=17986.580,P<0.001);2017-2019年组的各季度流感样病例百分比高于2020-2022年组;2017-2019年组的一级医院、三级医院流感样病例百分比高于2020-2022年组,二级医院流感样病例百分比低于2020-2022年组;通过预测分析2023年流感样病例数以及流感样病例百分比,预测值在2023年1-3月以及10-12月出现季节性高峰。结论2020-2022年新型冠状病毒感染疫情流行期间,流感样病例的流行特征发生显著变化,随着新型冠状病毒感染疫情相关政策的优化与调整,未来依然建议加强流感疫苗的接种,提高疫苗接种率,降低流感样病例的传播风险。

Brainstem folding in an influenza child with Dandy-Walker variant

BACKGROUND Influenza in children is a major cause of morbidity and mortality worldwide.Nervous system diseases are a factor relating to increased mortality rate.However, reports of how these underlying diseases contribute to the death of children with influenza are rare.CASE SUMMARY A 4-year-old-girl developed type A influenza-related encephalopathy(IAE) with seizures, acute disorder of consciousness, and intracranial hypertension(cerebrospinal fluid pressure: 250 mm H2O), and the Dandy-Walker variant was found by her first magnetic resonance imaging(MRI) when admission. Three days later, she suddenly presented anisocoria, acute pulmonary edema, and coma, and the later MRI found that she had compressed brainstem, oblongata "Zlike folding", and swelling bilateral basal ganglia. After admission, the patient were tested for routine and special biomarkers and underwent neuroimaging and neuroelectrophysiology examinations as well as Oseltamivir and intravenous immunogloblin treatments. When predicting that unstable intracranial structures detected by MRI might have disastrous consequences in the progression of IAE,she was transferred into the pediatric intensive care unit and underwent continuous assessment of clinical condition while she did not have instability of basic vital signs;at the same time, her parents were fully informed about the risk and prognosis. Although she was ultimately dead from brain stem failure, the parents expressed understanding and did not trigger a doctor-patient conflict.CONCLUSION In case of finding an unstable intracranial structure, intensive care should be given to IAE patient and their clinical condition should be monitored continuously.

基于Omega方法的ASME CC2605-4&3蠕变计算对比分析

规范案例ASME CC2605-4于2021年7月实施。与CC2605-3相比,新标准的蠕变参数(Omega参数和应变率参数)有较大变化。通过解析计算,探讨了温度和等效应力对新旧规范蠕变参数的影响;结合算例,利用Ansys Workbench验算了新旧规范的蠕变损伤,并与解析计算形成对比。结果表明,有限元与解析计算结果吻合,新旧规范中蠕变参数随温度、等效应力变化的规律是一致的,且新规范的Omega参数随等效应力单调递增变化的起点更低,可进一步降低蠕变子程序开发时的最低应力限制,更贴合实际;当温度恒定400℃,初始应力高于220 MPa时,CC2605-4的蠕变损伤总是高于CC2605-3的数值。

2015-2022年西藏流感病毒变化趋势及病原学监测分析

目的回顾性分析2015—2022年西藏流感样病例(influenza-like illness,ILI)逐年变化趋势、季节变化趋势及病原学特征与变化规律,为西藏自治区ILI防控提供科学依据,为其他相关传染性疾病防控提供支撑和借鉴。方法收集2015—2022年西藏ILI病例资料及主要病原学分型(H1N1、H3N2、BV、BY)结果,统计分析ILI监测情况。结果2015—2022年8年间西藏门/急诊总数为585650例,共报告ILI数为18216例,以2021年、2016年和2019年ILI百分比最高。ILI月份分布特征描述显示,1—5月波动上升,5月最高,5—8月下降,8月最低;ILI季节分布特征描述显示,ILI在冬季和春季高发,在夏季和秋季发病率较低。病原学监测结果显示,2015—2022年8年间,流感病毒主要分型为BV型和H3N2型。结论西藏应进一步加强ILI监测质量控制,同时应充分发挥流感疫苗和非药物干预的双重作用,以降低流感的流行。

儿童急性坏死性脑病26例临床特征及预后分析

目的总结儿童急性坏死性脑病(ANEC)的临床特征、治疗过程和预后。方法回顾性分析2016年6月至2022年12月确诊ANEC患儿的临床资料。对存活患儿进行电话随访,应用儿童整体表现分类量表(POPC)评估患儿生存质量。结果共纳入26例ANEC患儿,男女比例为1.6∶1,中位年龄36.0(23.0~69.0)个月。发病季节以夏季常见(42.3%),其次为冬季(34.6%);前驱感染以流感病毒感染多见(34.6%),其次为人类疱疹病毒6B型及新型冠状病毒。所有患儿均有发热伴不同程度意识障碍,24例出现惊厥。神经影像学以对称性丘脑受累(100%)为典型改变,多伴有基底节区(50.0%)、脑干(61.5%)、小脑(26.9%)等部位受累。23例患儿接受甲基泼尼松龙激素冲击治疗,住院病死率为23.1%(6/26),出院6个月后累积病死率为30.7%(8/26)。6个月后随访到14例存活患儿,11例接受康复治疗,其中POPC评估2分1例,3分4例,4分6例,5分1例,6分2例。3例新型冠状病毒感染后ANEC患儿3个月随访POPC评估结果为2分2例,6分1例。结论华南地区ANEC于夏季和冬季高发,新型冠状病毒感染可诱发ANEC;临床表现为发热、抽搐、意识障碍三联征,典型影像学改变为双侧丘脑受累。早期免疫治疗及综合康复训练有助于减少神经系统后遗症的严重程度。

流感相关性曲霉菌病患者发病及预后影响因素病例对照研究

目的:探讨流感相关性曲霉菌病(IAA)患者发病及预后的影响因素,以确定流感感染环境中侵袭性曲霉病的特定危险因素。方法:选取2014年1月1日—2019年12月31日肇庆市第一人民医院收治的383例流感患者作为研究对象,根据其是否患IAA分为病例组(26例)和对照组(357例),比较两组患者的一般情况、发病和预后特征。结果:病例组患者年龄大于对照组患者,差异有统计学意义(t=2.404,P<0.05);病例组患者慢性呼吸道疾病、心血管疾病患病率高于对照组患者,病例组有吸烟史的患者高于对照组患者,差异有统计学意义(χ^(2)=5.093,P<0.05);病例组患者呼吸衰竭、休克、多器官功能障碍综合症(MODS)、并发症发生率高于对照组患者,差异有统计学意义(χ^(2)=19.019、4.014,P<0.05);病例组患者病毒转阴率、治愈率低于对照组患者,差异有统计学意义(χ^(2)=16.780、34.774,P<0.05);病例组患者APACHEⅡ评分高于对照组患者,差异有统计学意义(t=6.552,P<0.05)。吸烟史是IAA发生的独立影响因素,有吸烟的患者比没吸烟的患者容易得IAA。IAA预后影响因素分析显示,死亡组患者吸烟史、并发症、呼吸衰竭、急性生理与慢性健康评分Ⅱ(APACHEⅡ)、心率(HR)、呼吸(R)、降钙素原(PCT)高于生存组患者,淋巴细胞、氧合指数低于生存组患者,差异有统计学意义(t=6.552、3.846、4.624、6.556、7.130、2.521,P<0.05)。结论:吸烟史是IAA发病的独立危险因素,吸烟的流感患者比非吸烟的患者易患IAA。生命体征不稳定、发生并发症、病情危重的IAA患者死亡风险可能更高。

2012-2015年北京市流感监测分析

目的了解北京市2012-2015年流感流行特征和流感病毒优势株的变化。方法使用＂北京市医疗机构传染病监测预警系统＂中二级以上医院流感样病例和百分比的周数据以及流感病原学监测周数据,分析流感样病例发病趋势和流感病毒构成情况。结果 2012年第27周至2015年第26周,北京市流感样病例（ILI）、流感样病例百分比（ILI%）与流感病毒阳性率变化趋势一致（r=0.801,P〈0.001;r=0.737,P〈0.001）,发病高峰为每年冬春季。不同监测季,流感样病例年龄组构成不同（χ^2=2.143,P〈0.001）,各监测季流感病毒亚型构成不同。共报告流感暴发疫情68起,其中62起（91.18%）由甲型H3N2引起,发生在小学校的疫情最多,为35起（51.47%）。结论 2012-2015年甲型H3N2亚型、甲型H1N1流感、乙型Yamagata系均有流行,且各年度优势毒株不一。ILI、ILI%和流感病毒阳性率三者的高峰基本吻合,证实了北京市流感监测系统在预警预测流感流行趋势和暴发疫情中的实际作用。