Outbreak Of Acute Respiratory Infection Research Articles

Commentary on the adoption of a test-based versus syndromic-based approach to outbreak declaration and management in hospital and institutional settings.

At present, Ontario, like most other jurisdictions in Canada, uses a syndromic-based surveillance definition for acute respiratory infection (ARI) outbreaks in institutions and public hospitals. Confirmed outbreaks are defined as either two or more ARIs in 48 hours with any common epidemiological link and at least one that is laboratory-confirmed; or three cases of ARIs occurring within 48 hours with any common epidemiological link, and not necessarily with lab confirmation. However, with the adoption of broader test-based approaches for sick patients/residents throughout the pandemic, new challenges have surfaced regarding the declaration and management of ARI outbreaks with a variety of scenarios in respiratory testing results. Decisions, including the determination of epidemiological linkage when there are discordant/negative test results, have become more complicated with the addition of virus-specific test results for every sick individual. The ARI outbreak case definition and management guidance was updated in 2018. The purpose of this commentary is to highlight epidemiological trends in ARI outbreaks in Ontario over the 2022-2023 season compared to the 2018-2019 and 2019-2020 pre-pandemic seasons. This is followed by a discussion around some of the benefits and challenges of implementing a test-based versus syndromic-based approach to ARI outbreaks.

Circulation of Respiratory Viruses in the City: Towards an Agent-Based Ecosystem model.

Mathematical models play an important role in management of outbreaks of acute respiratory infections (ARI). While such models are generally used to study the spread of a solitary virus, in reality multiple viruses co-circulate in the population. These viruses have been studied in detail, including the course of infection and immune defense mechanisms. We developed an agent-based model, called ABM-ARI, assimilating heterogeneous data and theoretical knowledge into a biologically motivated system, that allows to reproduce the seasonal patterns of ARI incidence and simulate interventions. ABM-ARI uses city-specific data to create a synthetic population and to construct realistic contact networks in different activity settings. Characteristics of infection, immune protection and non-specific resistance were varied between individuals to account for the population heterogeneity. For the calibration, we minimised the normalised mean absolute error between simulated and observed epidemic curves. ABM-ARI was built based on the quantitative assessment of features of predominant respiratory viruses and epidemiological characteristics of the population. It provides a good fit to the observed epidemic curves for different age groups and viruses. We also simulated one-week school closures when student absences were at or above 10%, 20% or 30% and found that only 10% and 20% thresholds resulted in a reduction of the incidence. ABM-ARI has a great potential in tackling the challenge of emerging infections by simulating and evaluating the effectiveness of various interventions.

Upsurge in hospitalization of pediatric patients with severe acute respiratory infections in Kolkata and surrounding districts caused by recombinant human respiratory adenovirus type B 7/3.

Globally, different genotypes of human adenoviruses are associated with outbreaks of acute respiratory infection (ARI) though such evidence is lacking from India. In the present study, we report a sudden increase in the positivity of respiratory adenovirus among hospitalized children with ARI from Kolkata and the surrounding districts of West Bengal, India, from December 2022 to date. A sharp rise in the positivity rate of respiratory adenovirus was found which ranged from 22.1% in early December 2022 to 52.6% in mid-March 2023. The overall positivity was 40.4% during the period and children in the 2 to <5 years (51.0%) age group were mostly affected. Single infection with adenovirus was found in 72.4% of cases while co-infection with rhinovirus was the maximum (9.4%). Around 97.5% of positive cases required hospitalization. Cough, breathlessness, and wheeze were the most common clinical features among positive patients. Phylogenetic analysis of the hexon and fiber gene of all the sequenced strains revealed HAdV-B 7/3 recombination with more than 99% homology within themselves. This report of a respiratory adenovirus outbreak in West Bengal, India causing severe illness in the pediatric population underscores the need for regular monitoring of the circulating strains.

Mask Wearing Behavior to Prevent Acute Respiratory Tract Infections During the COVID-19 Pandemic Among Students in Jakarta

Introduction: The incidence of acute respiratory infections (ARI) tends to be higher in urban areas, especially in Jakarta, the centre of activity in Indonesia. However, the COVID-19 pandemic forced people to wear masks in both urban and rural areas to prevent the virus from entering the respiratory tract. The purpose of this study was to identify the relationship between mask-wearing behaviour and outbreaks of acute respiratory infections during the COVID-19 pandemic among students in Jakarta.&#x0D; Methods: The design of this study was cross-sectional. The consecutive sampling technique was used to select 328 students as the respondents. The independent variable was mask-wearing behaviour (knowledge, attitude, practice). The dependent variable was ARI. The data were collected using a Google Forms questionnaire and then analysed by using the Chi-square test and multiple logistic regression test with a significance level of p &lt; 0.05.&#x0D; Results: The result showed that respondents had good knowledge (57%), positive attitude (56.7%), good practice (50.6%), and did not have a history of ISPA (64.3%). The predictive factors affecting ARI showed significant results in the attitude domain (p &lt;0.05; OR 1.907).&#x0D; Conclusion: This study found a connection between mask-wearing behaviour and knowledge, attitude, and practice to prevent ARI. We propose normalizing the use of masks even though the number of COVID-19 infections is gradually decreasing to prevent respiratory infections caused by the high rate of air pollution in urban areas.

Epidemiology and pathogen study of an outbreak in clusters caused by human adenovirus type 4 in Shenzhen

Objective To analyze the epidemiological and pathogenetic characteristics of a community outbreak of acute respiratory tract infection by Human adenovirus serotype 4 (HAdV-4) at a primary school in Baoan district, Shenzhen, Feb.22-28, 2019. Methods All epidemiological and clinical information of these cases was collected through field interviews and medical records. Throat swabs samples were collected and tested for influenza virus in quantitative fluorescence PCR. Influenza virus negative samples were then PCR tested for 6 other common respiratory virus. HAdV-4 positive samples were further tested using hexon gene sequencing of adenovirus. The sequences were aligned with the GenBank data to determine the genotypes and draw the phylogenetic tree. Results The epidemic occurred in Class 1, Grade 2, with a total of 54 students, including 29 boys and 25 girls. After investigation, there were no cases of similar symptoms in other classes of the school. Totally 13 patients were diagnosed, including 7 boys and 6 girls, the incidence rate was 24.1%(7 / 29) and 24.0% (6/25), respectively. The clinical symptoms included fever (13 cases, 100.0%), sore throat (8, 61.5%), muscular ache (8, 61.5%) and cough (5, 38.5%). All the symptoms were mild, and there were no severe cases. All 5 throat swabs samples were adenovirus positive by PCR, and these positive samples were confirmed to be HAdV-4 subgroups E by DNA sequence analysis. Conclusion The acute respiratory infection outbreak was caused by HAdV-4. The sequence of the strain is highly homologous with sequences from other districts of Shenzhen and Chinese cities. 摘要：目的 分析2019年2月22—28日深圳市宝安区某小学一起急性呼吸道病毒感染聚集性疫情的流行病学及 病原学特点。 方法 采用流行病学个案调査表对疫情进行现场调査, 使用荧光定量 PCR 方法对采集的咽拭子标本进 行流感样病例病原学筛査, 筛査阴性标本进行6种常见呼吸道病毒核酸检测。对腺病毒核酸阳性的标本, 用腺病毒六 邻体基因作为靶基因进行序列扩增及测定, 测序结果在GenBank上进行序列比较, 确定其病毒亚型并进行系统进化分 析。 结果 疫情发生在二年级(1)班, 全班共54名学生, 男29名, 女25名。经调査该学校其他班级其余年级未出现相 同症状病例。该起疫情共发现病例13例, 其中男生7例, 女生6例, 男女学生罹患率分别为24.1%( 7 /29)和24.0% ( 6 /25)。临床特征为发热13例(100.0%), 咽痛8例(61.5%), 全身肌肉酸痛8例(61.5%), 咳嗽5例(38.5%), 症状均较轻, 无重 症病例。共采集5份咽拭子标本 , 经荧光定量PCR检测均为腺病毒核酸阳性 , 5份标本用分型引物检测并分析序列确 定均为腺病毒E亚属4型。 结论 此次急性呼吸道感染聚集性疫情由腺病毒4型引起, 毒株序列与深圳其他区、国内 其他城市分离的腺病毒4型毒株序列具有髙度同源性。

An outbreak of acute respiratory infection at a training base in Beijing, China due to human adenovirus type B55

BackgroundTwelve students experienced symptoms of acute respiratory infection (ARI) at a training base in Beijing from August 26 to August 30, 2015. We investigated the cause of this ARI outbreak.MethodsIn partnership with the local center for disease control, we collected a total of twelve pharyngeal swab specimens as well as demographic information for the affected patients. We used multiplex real-time PCR to screen for sixteen common respiratory viruses in these samples. To isolate HAdV, we inoculated Hep-2 cells with the human adenovirus (HAdV)-positive samples and then carried out sequencing and phylogenetic analysis of the hexon, fiber, and penton genes of the isolated adenoviruses. In addition, we analyzed the entire genome of one strain isolated from the index case to identify single-nucleotide substitutions.ResultsWe identified ten HAdV-positive students using multiplex real-time PCR. None of the students were co-infected with other viruses. We successfully isolated seven HAdV strains from the pharyngeal swab specimens. The coding sequences of the hexon, fiber, and penton genes of these seven HAdV strains were identical, suggesting that they represented seven strains from a single virus clone. One HAdV isolate obtained from the index case, BJDX-01-2015, was selected for whole genome analysis. From this isolate, we obtained a 34,774-nucleotide sequence. The genome of BJDX-01-2015 clustered with HAdV-B55 in phylogenetic analyses and had 99.97% identity with human adenovirus 55 isolate HAdV-B/CHN/BJ01/2011/55 (GenBank accession no. JX491639).ConclusionsWe identified HAdV-B55 as the strain associated with the August 2015 ARI outbreak at a training base in Beijing. This was the first reported outbreak in Beijing due to HAdV-B55. Continuous surveillance of respiratory adenoviruses is urgently needed to understand the epidemiological and evolutionary features of HAdV-B55, and an epidemiological modeling approach may provide further insights into this emerging public health threat. Furthermore, the clinical laboratory data from this outbreak provides important reference for the clinical diagnosis and may ultimately aid in informing the development of strategies to control and prevent respiratory tract infections caused by HAdV-B55.

Seasonal outbreak of acute respiratory infections and role of belladonna as a “Genus homeopathic remedy”

Seasonal outbreak of acute respiratory infections and role of belladonna as a “Genus homeopathic remedy”

School sessions are correlated with seasonal outbreaks of medically attended respiratory infections: electronic health record time series analysis, Wisconsin 2004-2011.

Increased social contact within school settings is thought to be an important factor in seasonal outbreaks of acute respiratory infection (ARI). To better understand the degree of impact, we analysed electronic health records and compared risks of respiratory infections within communities while schools were in session and out-of-session. A time series analysis of weekly respiratory infection diagnoses from 28 family medicine clinics in Wisconsin showed that people under the age of 65 experienced an increased risk of ARI when schools were in session. For children aged 5-17 years, the risk ratio for the first week of a school session was 1.12 (95% confidence interval (CI) 0.93-1.34), the second week of a session was 1.39 (95% CI 1.15-1.68) and more than 2 weeks into a session was 1.43 (95% CI 1.20-1.71). Less significant increased risk ratios were also observed in young children (0-4 years) and adults (18-64 years). These results were obtained after modelling for baseline seasonal variations in disease prevalence and controlling for short-term changes in ambient temperature and relative humidity. Understanding the mechanisms of seasonality make it easier to predict outbreaks and launch timely public health interventions.

An Outbreak of Human Parainfluenza Virus 3 (Phylogenetic Subcluster C5) Infection among Adults at a Residential Care Facility for the Disabled in Croatia, 2018

Introduction: Although highly pertinent for children, outbreaks of human parainfluenza virus (HPIV) may cause up to 15% of all respiratory illnesses in adults and predispose them to serious adverse outcomes, with HPIV serotype 3 (HPIV3) being the most common. This study represents the first report of an HPIV3 outbreak among adults at a long-term health-care facility in Croatia. Methods: A retrospective study was conducted to investigate an outbreak of acute respiratory infection (ARI) at a single residential care facility for the disabled in Croatia. Demographic, epidemiological, and clinical data were collected for all residents, while hospitalized patients were appraised in detail by laboratory/radiological methods. Multiplex PCR for respiratory viruses and sequencing was performed. Partial HPIV3 HN 581 nt sequences were aligned with HPIV3 sequences from the GenBank database to conduct a phylogenetic analysis, where different bioinformatic approaches were employed. Results: In late June 2018, 5 of the 10 units at the facility were affected by the outbreak. Among the 106 residents, 23 (21.7%) developed ARI, and 6 (26.1%) of them were hospitalized. HPIV3 was identified in 18 (73%) of the residents and 5 (83%) of the hospitalized individuals. Isolated HPIV3 strains were classified within the phylogenetic subcluster C5 but grouped on 2 separate branches of the phylogenetic tree. During the entire outbreak period, none of the institution’s employees reported symptoms of ARI. Conclusions: Our study has shown that this health care-associated outbreak of HPIV3 infection could have been linked to multiple importation events. Preventive measures in curbing such incidents should be enforced vigorously.

Epidemiological Investigation of the Outbreak of Acute Respiratory Infection caused by Adenovirus Type B55 in a Physical Education School in 2017

BackgroundOn May 19, 2017, the cluster of 6 acute respiratory infections due to adenovirus in the swimming department of a physical education school (School J) was reported to Korea Centers for Disease Control and Prevention. An epidemiological investigation was conducted to identify the transmission route of the infection and to control the outbreak.Materials and MethodsA retrospective cohort study (Study 1) was conducted on students and teachers of the athletic departments using the swimming pool, and a prospective surveillance (Study 2) was conducted on all students and teachers of the School J. A case was defined as any student and school personnel who developed more than two of the following symptoms from April 10 to July 2, 2017: fever, sore throat, cough, rhinorrhea, or headache. Relative risks (RRs) were calculated to compare the attack rates according to potential risk factors. Multivariable logistic regression was performed to identify the risk factors for infection in the outbreak.Results47 cases were identified: 33 (55.9%) cases occurred among 59 students and teachers in Study 1 and 14 (3.9%) among 362 students and school personnel in Study 2. There were 18 laboratory confirmed adenovirus infection cases. The common symptoms were headache (71.7%), fever (69.6%), rhinorrhea (63.0%), sputum (56.5%), and sore throat (54.3%). 23.9% of the cases were accompanied with diarrhea and 19.6% with eye congestion. None of the cases developed pneumonia. 32.6% of the cases were hospitalized. In Study 1, attack rate in the swimming department was higher than that in others (RR: 1.90; 95% confidence interval [CI]: 1.01-3.60). In Study 2, being a member of the shooting department (RR: 20.70; 95% CI: 4.90-87.47) and being a first year high school student (RR: 10.95; 95% CI: 2.90-41.33) were identified as risk factors for the infections. Genetic analyses of the adenoviruses showed 100% identical sequence in homology and confirmed the human adenovirus B55 (HAdV-B55). No adenovirus was detected at examining the water and environment of the swimming pool and dormitory.ConclusionThe outbreak is inferred to be occurred via propagated transmission among the students in the same athletic department, while the students with symptoms of respiratory infection continued performing school activities without any restrictions. Infection control measures such as early detection of symptoms of respiratory infection and restriction of group activity are necessary to prevent respiratory infection outbreak in the communal living setting.

Control of a Mycoplasma pneumoniae Outbreak in an Institutional Setting Using Azithromycin Prophylaxis.

Mycoplasma pneumoniae is a major cause of respiratory infection of varying severity. Outbreaks of M. pneumoniae infection commonly occur in closed or semi-closed communities and settings. The control of such outbreaks is challenging, owing to delayed detection, long incubation period, and paucity of infection control guidelines. Between May and July 2015, a residential facility for adults with developmental disabilities in Southern Israel witnessed an outbreak of acute respiratory infection, subsequently diagnosed as associated with M. pneumoniae. All relevant data were collected as a part of a formal outbreak investigation. Strict infection control procedures were implemented, and azithromycin prophylaxis was provided to all residents. Out of 215 residents, there were 29 suspected cases, 23 of which were confirmed as M. pneumoniae infection by serology or nucleic acid testing, for an attack rate of 11%. There were no cases of severe or fatal illness. An infection control strategy, including implementation of strict case isolation, enforcement of hygiene measures, a high index of suspicion for case detection, and use of azithromycin prophylaxis for all residents, led to rapid cessation of the outbreak. The use of azithromycin prophylaxis may be worthwhile in closed institutional settings in which M. pneumoniae infections are documented. The dynamics of this outbreak suggest that if spread between wards is anticipated, expanding prophylaxis beyond immediate contacts of affected individuals should be considered.

Shelter crowding and increased incidence of acute respiratory infection in evacuees following the Great Eastern Japan Earthquake and tsunami.

Although outbreaks of acute respiratory infection (ARI) at shelters are hypothesized to be associated with shelter crowding, no studies have examined this relationship. We conducted a retrospective study by reviewing medical records of evacuees presenting to one of the 37 clinics at the shelters in Ishinomaki city, Japan, during the 3-week period after the Great Eastern Japan Earthquake and tsunami in 2011. On the basis of a locally weighted scatter-plot smoothing technique, we categorized 37 shelters into crowded (mean space <5·5 m2/per person) and non-crowded (⩾5·5 m2) shelters. Outcomes of interest were the cumulative and daily incidence rate of ARI/10 000 evacuees at each shelter. We found that the crowded shelters had a higher median cumulative incidence rate of ARI [5·4/10 000 person-days, interquartile range (IQR) 0-24·6, P = 0·04] compared to the non-crowded shelters (3·5/10 000 person-days, IQR 0-8·7) using Mann-Whitney U test. Similarly, the crowded shelters had an increased daily incidence rate of ARI of 19·1/10 000 person-days (95% confidence interval 5·9-32·4, P < 0·01) compared to the non-crowded shelters using quasi-least squares method. In sum, shelter crowding was associated with an increased incidence rate of ARI after the natural disaster.

Outbreak of acute respiratory infection in a care home for the vulnerable elderly: investigation, management and challenges

On the afternoon of Friday 2nd April 2012, the West Midlands East Health Protection Team (HPT), based in Birmingham UK, was contacted by a NHS Primary Care Trust (PCT) infection control nurse. Seven deaths due to respiratory illness had occurred since the 13th of March in a 70 bed care home for elderly and end of life patients. The home was contacted and they reported that 18 residents and two members of staff had suffered chest infections since 27th February.

Molecular epidemiology of a post-influenza pandemic outbreak of acute respiratory infections in Korea caused by human adenovirus type 3.

An outbreak of upper respiratory tract infections associated with human adenovirus (HAdV) occurred on a national scale in Korea from September to December 2010, following a major H1N1 influenza pandemic. Data from the Korea Influenza and Respiratory Surveillance System (KINRESS) showed an unusually high positive rate accounting for up to 20% of all diagnosed cases. To determine the principal cause of the outbreak, direct polymerase chain reaction (PCR) amplification followed by sequence analysis targeting parts of the hexon gene of HAdV was performed. Serotypes of 1,007 PCR‐diagnosed HAdV‐positive samples from patients with an acute upper respiratory tract illness were determined and epidemiological characteristics including major aged group and clinical symptoms were analyzed. The principal symptom of HAdV infections was fever and the vulnerable aged group was 1–5 years old. Based on sequence analysis, HAdV‐3 was the predominant serotype in the outbreak, with an incidence of 74.3%. From the beginning of 2010 until May, the major serotypes were HAdV‐1, 2, and 5 (70–100%) in any given period. However, an outbreak dominated by HAdV‐3 started between July and August and peaked in September. Phylogenetic analysis revealed that there was no genetic variation in HAdV‐3. The results demonstrated that an outbreak of upper respiratory illness followed by H1N1 influenza pandemic in Korea was caused mainly by emerged HAdV‐3. J. Med. Virol. 87: 10–17, 2015. © 2014 Wiley Periodicals, Inc.

An outbreak of acute respiratory infections due to human respiratory syncytial virus in a nursing home for the elderly in Ibaraki, Japan, 2014.

An outbreak of acute respiratory infections due to human respiratory syncytial virus in a nursing home for the elderly in Ibaraki, Japan, 2014.

Using the Electronic Medical Record to Identify Community-Acquired Pneumonia: Toward a Replicable Automated Strategy

BackgroundTimely information about disease severity can be central to the detection and management of outbreaks of acute respiratory infections (ARI), including influenza. We asked if two resources: 1) free text, and 2) structured data from an electronic medical record (EMR) could complement each other to identify patients with pneumonia, an ARI severity landmark.MethodsA manual EMR review of 2747 outpatient ARI visits with associated chest imaging identified x-ray reports that could support the diagnosis of pneumonia (kappa score = 0.88 (95% CI 0.82∶0.93)), along with attendant cases with Possible Pneumonia (adds either cough, sputum, fever/chills/night sweats, dyspnea or pleuritic chest pain) or with Pneumonia-in-Plan (adds pneumonia stated as a likely diagnosis by the provider). The x-ray reports served as a reference to develop a text classifier using machine-learning software that did not require custom coding. To identify pneumonia cases, the classifier was combined with EMR-based structured data and with text analyses aimed at ARI symptoms in clinical notes.Results370 reference cases with Possible Pneumonia and 250 with Pneumonia-in-Plan were identified. The x-ray report text classifier increased the positive predictive value of otherwise identical EMR-based case-detection algorithms by 20–70%, while retaining sensitivities of 58–75%. These performance gains were independent of the case definitions and of whether patients were admitted to the hospital or sent home. Text analyses seeking ARI symptoms in clinical notes did not add further value.ConclusionSpecialized software development is not required for automated text analyses to help identify pneumonia patients. These results begin to map an efficient, replicable strategy through which EMR data can be used to stratify ARI severity.

Computerized Text Analysis to Enhance Automated Pneumonia Detection

Information about disease severity could help with both detection and situational awareness during outbreaks of acute respiratory infections. In this work, we describe the methods by which automated text analyses of chest imaging reports can combine with structured EMR data to accurately identify outpatients with pneumonia (sensitivities of 58-75%, and PPV of 64-86%).

Outbreak of Acute Respiratory Infection among Infants in Lisbon, Portugal, Caused by Human Adenovirus Serotype 3 and a New 7/3 Recombinant Strain

Human adenoviruses (AdVs) typically cause mild illnesses in otherwise healthy hosts. We investigated a pediatric outbreak of acute respiratory infection with fatal outcomes that occurred in Lisbon, Portugal, in 2004. Biological specimens were collected from 83 children attending two nurseries, a kinesiotherapy clinic, and the household of a nanny. Adenovirus infection was confirmed in 48 children by PCR and virus isolation. Most (96%) isolates were classified as being of subspecies B1. Phylogenetic analysis of fiber and hexon gene sequences revealed that most infants were infected with AdV serotype 3 (AdV3) strains. Infants attending one nursery harbored a new recombinant strain containing an AdV serotype 7 hexon and serotype 3 fiber (AdV7/3). Both the AdV3 and the AdV7/3 strains caused fatal infections. Two different serotype 3 strains were circulating in Lisbon in 2004, and the new AdV7/3 recombinant type originated from only one of those strains. These results demonstrate that recombination leads to the emergence of new adenovirus strains with epidemic and lethal potential.

Tests rapides de surveillance (TRS) de la grippe en établissements accueillant des personnes âgées : évaluation de quatre années d’utilisation dans le cadre du réseau Grog Géronto-Alsace

Objective Outbreaks of acute respiratory infections (ARI) are common in institutions for elderly people. The objective of our study was the assessment of immunoassay rapid test used for influenza diagnosis in institutions for elderly people. Methodology Prospective surveillance for ARI was conducted in 11 institutions in Alsace over a four-year period. Clinical case definitions are used to identify the infected residents. For the identification of influenza virus, nasopharyngeal swabs are obtained and rapid tests (immunoassay) are performed. Results Influenza virus was identified with immunoassay rapid test. Then, prophylaxis according to the Conseil supérieur d’hygiène publique de France guidelines was implemented. Nevertheless, the use of the rapid test was not frequent in the individual institution and the information recorded at the Grog Géronto-Alsace level could be use to inform the institutions when it is important to perform these rapid tests. Conclusion Ours findings show the value of the rapid test used in the influenza surveillance and how the networks could help to improve their uses.

Serologic study on the outbreak of acute upper respiratory tract infections caused by adenovirus 3

From April to June, 2004, an outbreak of acute upper respiratory tract infections (AURTI) occurred in the north area of Jiangsu Province, China. Twenty throat swabs were collected with 13 of them presenting an adenovirus (Ad)-like cytopathogenic effect on HEp-2. These were verified as Ad by the electron microscope, direct immunofluorescence assay and Ad primer-mediated PCR. Moreover, they were identified as adenovirus type 3 (Ad3) by type-specific PCR and sequencing of the amplification products. Subsequent serologic studies were carried out to finally diagnose and document the outbreak. The neutralization test of paired serum of six in nine cases show obviously increased antibodies titers. The positive rate of IgM, IgG and recovery phase neutralization antibodies of the cases were 3.7%, 44.4% and 59.5% respectively while those of the controls were 0%, 8.3% and 33.3% respectively. The P values of Chi-Square were 0.510, 0.018 and 0.226 respectively. The concordance between IgG detected by ELISA and neutralization anti bodies detected by the neutralization test was 61.4% and the P value of Kappa was 0.070. By the serologic study, we can definitively diagnose that this outbreak of acute respiratory infections was caused by Adenovirus 3.