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At least 217 records · Page 12Linked to original sources
PubMed2006

Linking healthcare associated norovirus outbreaks: a molecular epidemiologic method for investigating transmission.

BACKGROUND: Noroviruses are highly infectious pathogens that cause gastroenteritis in the community and in semi-closed institutions such as hospitals. During outbreaks, multiple units within a hospital are often affected, and a major question for control programs is: are the affected units part of the same outbreak or are they unrelated transmission events? In practice, investigators often assume a transmission link based on epidemiological observations, rather than a systematic approach to tracing transmission.Here, we present a combined molecular and statistical method for assessing:1) whether observed clusters provide evidence of local transmission and2) the probability that anecdotally|linked outbreaks truly shared a transmission event. METHODS: 76 healthcare associated outbreaks were observed in an active and prospective surveillance scheme of 15 hospitals in the county of Avon, England from April 2002 to March 2003. Viral RNA from 64 out of 76 specimens from distinct outbreaks was amplified by reverse transcription-PCR and was sequenced in the polymerase (ORF 1) and capsid (ORF 2) regions. The genetic diversity, at the nucleotide level, was analysed in relation to the epidemiological patterns. RESULTS: Two out of four genetic and epidemiological clusters of outbreaks were unlikely to have occurred by chance alone, thus suggesting local transmission. There was anecdotal epidemiological evidence of a transmission link among 5 outbreaks pairs. By combining this epidemiological observation with viral sequence data, the evidence of a link remained convincing in 3 of these pairs. These results are sensitive to prior beliefs of the strength of epidemiological evidence especially when the outbreak strains are common in the background population. CONCLUSION: The evidence suggests that transmission between hospitals units does occur. Using the proposed criteria, certain hypothesized transmission links between outbreaks were supported while others were refuted. The combined molecular/epidemiologic approach presented here could be applied to other viral populations and potentially to other pathogens for a more thorough view of transmission.

Caliciviridae Infections↗
PubMed2003

Foodborne disease in Australia: incidence, notifications and outbreaks. Annual report of the OzFoodNet network, 2002.

In 2002, OzFoodNet continued to enhance surveillance of foodborne diseases across Australia. The OzFoodNet network expanded to cover all Australian states and territories in 2002. The National Centre for Epidemiology and Population Health together with OzFoodNet concluded a national survey of gastroenteritis, which found that there were 17.2 (95% C.I. 14.5-19.9) million cases of gastroenteritis each year in Australia. The credible range of gastroenteritis that may be due to food each year is between 4.0-6.9 million cases with a mid-point of 5.4 million. During 2002, there were 23,434 notifications of eight bacterial diseases that may have been foodborne, which was a 7.7 per cent increase over the mean of the previous four years. There were 14,716 cases of campylobacteriosis, 7,917 cases of salmonellosis, 505 cases of shigellosis, 99 cases of yersiniosis, 64 cases of typhoid, 62 cases of listeriosis, 58 cases of shiga toxin producing E. coli and 13 cases of haemolytic uraemic syndrome. OzFoodNet sites reported 92 foodborne disease outbreaks affecting 1,819 persons, of whom 5.6 per cent (103/1,819) were hospitalised and two people died. There was a wide range of foods implicated in these outbreaks and the most common agent was Salmonella Typhimurium. Sites reported two outbreaks with potential for international spread involving contaminated tahini from Egypt resulting in an outbreak of Salmonella Montevideo infection and an outbreak of suspected norovirus infection associated with imported Japanese oysters. In addition, there were three outbreaks associated with animal petting zoos or poultry hatching programs and 318 outbreaks of suspected person-to-person transmission. Sites conducted 100 investigations into clusters of gastrointestinal illness where a source could not be identified, including three multi-state outbreaks of salmonellosis. OzFoodNet identified important risk factors for foodborne disease infection, including: Salmonella infections due to chicken and egg consumption, bakeries as a source of Salmonella infection, and problems associated with spit roast meals served by mobile caterers. There were marked improvements in surveillance during 2002, with all jurisdictions contributing to national cluster reports, increasing use of analytical studies to investigate outbreaks and 96.9 per cent of Salmonella notifications on state and territory surveillance databases recording complete information about serotype and phage type. During 2002, there were several investigations that showed the benefits of national collaboration to control foodborne disease. Sharing surveillance data from animals, humans and foods and rapid sharing of molecular typing information for human isolates of potentially foodborne organisms could further improve surveillance of foodborne disease in Australia.

Adolescent↗
PubMed2000

Continuous source outbreak of campylobacteriosis traced to chicken.

Poultry is a source of human campylobacteriosis, but a large continuous source outbreak, heretofore, has not been attributed to both a single source of poultry and single serotype of Campylobacter. Here we report an outbreak of C. jejuni affecting 6 catering college trainees and 13 patrons of a restaurant in southern England. An epidemiological investigation successfully tracked the outbreak source to the farm of origin. Frequency of occurrence of campylobacters and outbreak serotype distribution were determined in index cases, the local population, and local chicken suppliers. The source farm was investigated and the effect of interventions assessed. A single outbreak serotype of C. jejuni was isolated from trainee chefs, patrons, and chicken supplied to the college by Wholesaler A. The Campylobacter isolation rate for Wholesaler A was 89% (98% outbreak serotype), compared to 40% for non-Wholesaler A (10% outbreak serotype). The isolation rate for 14 months averaged 85% (99% outbreak serotype) in chickens grown on two farms (X and Y) supplying Wholesaler A, contributing approximately 40% to all local cases. In the research reported here, a specific strain and hygiene practice were found to be important for understanding transmission of Campylobacter from poultry to humans in this outbreak.

Adolescent↗
PubMed2006

Systematic environmental evaluations to identify food safety differences between outbreak and nonoutbreak restaurants.

Restaurants are important settings for foodborne disease transmission. The Environmental Health Specialists Network (EHS-Net) was established to identify underlying factors contributing to disease outbreaks and to translate those findings into improved prevention efforts. From June 2002 through June 2003, EHS-Net conducted systematic environmental evaluations in 22 restaurants in which outbreaks had occurred and 347 restaurants in which outbreaks had not occurred. Norovirus was the most common foodborne disease agent identified, accounting for 42% of all confirmed foodborne outbreaks during the study period. Handling of food by an infected person or carrier (65%) and bare-hand contact with food (35%) were the most commonly identified contributing factors. Outbreak and nonoutbreak restaurants were similar with respect to many characteristics. The major difference was in the presence of a certified kitchen manager (CKM); 32% of outbreak restaurants had a CKM, but 71% of nonoutbreak restaurants had a CKM (odds ratio of 0.2; 95% confidence interval of 0.1 to 0.5). CKMs were associated with the absence of bare-hand contact with foods as a contributing factor, fewer norovirus outbreaks, and the absence of outbreaks associated with Clostridium perfringens. However, neither the presence of a CKM nor the presence of policies regarding employee health significantly affected the identification of an infected person or carrier as a contributing factor. These findings suggest a lack of effective monitoring of employee illness or a lack of commitment to enforcing policies regarding ill food workers. Food safety certification of kitchen managers appears to be an important outbreak prevention measure, and managing food worker illnesses should be emphasized during food safety training programs.

Caliciviridae Infections↗
PubMed1995

Prospective study of diarrhoeal outbreaks in child long-daycare centres in western Sydney.

OBJECTIVE: To investigate outbreaks of diarrhoeal illness in children attending long-daycare centres (LDCs), to characterise parasitic, bacterial and viral isolates from the children's faeces and to identify individual and LDC risk factors for diarrhoea. DESIGN: Eleven-month prospective case-control study of diarrhoeal outbreaks among children in LDCs. SUBJECTS: 2368 children attending 35 LDCs in the western Sydney area. MAIN OUTCOME MEASURES: Frequency of diarrhoeal outbreaks, rate of attack and spread to family members; pathogens isolated from stools; and individual and LDC risk factors. RESULTS: The overall incidence of diarrhoeal disease was low (0.28 outbreaks per centre per year and 0.056 outbreak-associated cases per child-year). Attack rates during outbreaks varied widely (4%-55%; mean, 15%), as did secondary spread rates to family members (1%-15%; mean, 9%). Pathogens were isolated from 7% of symptomatic children and 7% of controls; no outbreak was shown to be caused by a recognised pathogen. Children with outbreak-associated diarrhoeal illness were more likely to have suffered vomiting, poor appetite, lack of energy, fever and to have taken antibiotics in the previous week than other children. Hygiene practices varied widely among centres. CONCLUSIONS: We found low incidence and morbidity from diarrhoeal illness in Australian urban LDCs. Diarrhoea in children in LDCs may be caused predominantly by non-infectious factors such as diet and antibiotic exposure. Current hygiene measures in LDCs seem adequate to prevent and contain outbreaks of infectious diarrhoea.

Child↗
PubMed2004

Epizootiology of an epizootic hemorrhagic disease outbreak in West Virginia.

An outbreak of epizootic hemorrhagic disease virus, serotype 2 (EHDV-2) was responsible for localized white-tailed deer (Odocoileus virginianus) mortality in Hardy and Hampshire counties, West Virginia (USA), in the summer and fall of 1993. Using available historical data on regional herd immunity, data opportunistically collected during the epizootic, and postepizootic sampling of hunter-harvested deer, we grossly estimate certain epidemiologic parameters and compare findings to a hypothesis about hemorrhagic disease outbreaks in the Appalachian Mountains. During the epizootic, 57.9 km(2) were actively searched and 228 dead deer were found. Epizootic hemorrhagic disease virus, serotype 2 was isolated from seven of nine deer sampled in Hardy and Hampshire counties. Preepizootic exposure of deer to EHD viruses was unknown, but available data suggest that it was negligible. The geographic distribution of the outbreak was defined by plotting the locations of dead deer found during the outbreak, as well as the locations of deer harvested by hunters after the outbreak that had antibodies to EHDV-2 on a map sectioned into 16.65 km(2) rectangular sections. Sections that included one or more dead deer or hunter-harvested deer with antibodies to EHDV-2 were included in the defined outbreak area. Postoutbreak sampling revealed monospecific EHDV-2 antibodies in 12% of deer harvested by hunters within the defined outbreak area. Based on the available data and accepting certain assumptions, gross calculations suggest that this outbreak appears to have been isolated and probably killed a high percentage of the deer that were infected. This is consistent with the hypothesis that sporadic hemorrhagic disease outbreaks in the Appalachian Mountains are usually localized and severe.

Animals↗
PubMed2000

Surveillance for outbreaks of respiratory tract infections in nursing homes.

BACKGROUND: Outbreaks of respiratory tract infections are common in long-term care facilities for older people. The objective of our study was to determine both the frequency of such outbreaks and their clinical and epidemiological features. METHODS: Prospective surveillance for outbreaks of respiratory tract infections and a retrospective audit of surveillance records were conducted in 5 nursing homes in metropolitan Toronto over 3 years. The clinical manifestations of infected residents were identified and microbiological investigations for causal agents were conducted. RESULTS: Sixteen outbreaks, involving 480 of 1313 residents, were identified prospectively during 1 144 208 resident-days of surveillance, for an overall rate of 0.42 infections per 1000 resident-days. Another 30 outbreaks, involving 388 residents, were identified retrospectively. Outbreaks occurred year-round, with no seasonal pattern. Pathogens included influenza virus, parainfluenza virus, respiratory syncytial virus, Legionella sainthelensi and Chlamydia pneumoniae. Multiple pathogens were detected in 38% (6/16) of the prospectively identified outbreaks. Of the 480 residents in the prospectively identified outbreaks 398 (83%) had a cough, 194 (40%) had fever and 215 (45%) had coryza. Clinical findings were nonspecific and could not be used to distinguish between causal agents. Pneumonia developed in 72 (15%) of the 480 residents, and 58 (12%) required transfer to hospital. The case-fatality rate was 8% (37/480). INTERPRETATION: Our findings emphasize the importance of adequate surveillance for outbreaks of respiratory tract infections in nursing homes and of early diagnosis so that appropriate interventions can be promptly instituted.

Aged↗
PubMed2000

Evolution of a laboratory based system for investigating outbreaks of infectious intestinal disease.

In 1995 Preston Public Health Laboratory introduced an incident logging system intended to improve the investigation of suspected outbreaks of infectious intestinal disease. A unique incident log (Ilog) number assigned and issued to the reporting individual and other interested parties when the laboratory is informed of a potential outbreak is used to identify all associated specimens submitted to the laboratory and is quoted in all communications about the incident. The results are reviewed formally each month. Between January 1995 and December 1998, 349 potential outbreaks of infectious intestinal disease were investigated, 325 of which were considered to be general outbreaks. Small round structured viruses were identified in 45% of these outbreaks, salmonellas in 8%, and no pathogens in 35%. Data from the national surveillance scheme for general outbreaks of infectious intestinal disease included 104 general outbreaks in 1996 and 1997 for the entire North West region, but our laboratory alone reported 184 general outbreaks during that period. The Ilog system is a simple and effective means for reviewing data from outbreaks, and helps to coordinate their investigation.

Clinical Laboratory Techniques↗
PubMed2003

[Serological characteristics of a hepatitis E outbreak].

OBJECTIVE: To look into the serological characteristics of a hepatitis E outbreak. METHODS: Sera from the first five patients with acute icteric hepatitis who developed the disease successively within ten days and the 1,675 employees routinely having their lunch in a dining hall of a department (outbreak population) were examined for anti.HEV IgM and IgG at 26th days after the outbreak, and the 883 employees of a neighboring department not having their lunch in the hall were selected as control (control population). RESULTS: The five patients were all positive for anti-HEV IgM and IgG. The positive rates of anti-HEV IgM and IgG in outbreak population were 8.7% and 38.4% respectively, both significantly higher than those in control population which were only 0.1% and 28.6%. The numbers with abnormal ALT in the 145 individuals with anti-HEV IgM(+) of outbreak population were significantly higher than those in the IgM(-) individuals of the same group as well as in control, while the abnormal ALT ratio in the IgM(-) individuals of the outbreak was not higher than that in control. The results from the four patients' serial sera showed that the anti-HEV IgM titers declined gradually and were undetectable at about 4th month after infection, and the IgG titers increased to peak in about 2-3 months after infection, then declined very slowly. The mean IgG titer of the anti-HEV IgM(+) individuals was significantly higher than that of the IgM(-) but IgG(+) individuals in outbreak population, and the latter was significantly higher than the IgG(+) individuals in control, which suggested that the post-infection individuals' immunities to HEV were boosted during the outbreak. There was no difference between sex or age groups for the anti-HEV IgM(+) ratio, but the abnormal ALT was much more frequent in the anti-HEV IgM(+) male than in the female, and no difference was observed between age groups. CONCLUSION: The pathogen of the outbreak of acute icteric hepatitis was hepatitis E virus and associated with food intake. Anti-HEV IgM and IgG were used not only for diagnosis of hepatitis E but also for surveilance in mass population. The attack risk was not associated with age or sex, but the abnormal ALT was much more frequent fresh infectors in male.

Adult↗
PubMed2004

[Outbreak of meningitis in the province of Logone occidental (Chad): descriptive study using health ministry data from 1998 to 2001].

UNLABELLED: Outbreaks of meningitis are a public health problem in sub-Saharan Africa where more than thousand cases are declared every year In Chad, the last outbreak happened between 1998 and 2001. The objective of this study is to describe epidemiologic profile of meningitis in the province of Logone Occidental from 1998 to 2001. METHODS: Study used epidemiologic data of surveillance's tools from years 1998 to 2001 in Chad. RESULTS: Data of the study indicated a two-yearly cycle with outbreaks in 1998 and 2000 occurring in endemic background during 1999 and 2001. The first cases began in January with an incidence rate close to 30 for 100.000/week. The epidemic peak occurred on the 11th week (1999-2001), on the 12th week (1998-2000) during dry season. Outbreak continued 9 weeks and stopped on the 16th week (April-May). The lethality average was 12% and reached 30% at the beginning of the outbreak. DISCUSSION: Despite vaccination campaigns during outbreaks, epidemiology did not change in Chad. Quality of epidemiological surveillance is not sufficient and political reaction is too slow. Moreover, human, material and financial deficiency add to these difficulties. Integrated vaccination against meningitis into the immunization preventive program was evocated but would not permit enough collective immunity. Biotope changes generated by human activity could contribute to perpetuating outbreaks. New outbreak of W135 meningitis in Burkina Faso (2002) may change the epidemiological profile of the meningitis in sub-Saharan Africa. CONCLUSION: Meningitis outbreaks control using vaccination after the first cases appears to be limited, however this strategy must be evaluated in Chad to know vaccination covering, target population and protection after vaccination.

Chad↗
PubMed2004

Measuring outbreak-detection performance by using controlled feature set simulations.

INTRODUCTION: The outbreak-detection performance of a syndromic surveillance system can be measured in terms of its ability to detect signal (i.e., disease outbreak) against background noise (i.e., normally varying baseline disease in the region). Such benchmarking requires training and the use of validation data sets. Because only a limited number of persons have been infected with agents of biologic terrorism, data are generally unavailable, and simulation is necessary. An approach for evaluation of outbreak-detection algorithms was developed that uses semisynthetic data sets to provide real background (which effectively becomes the noise in the signal-to-noise problem) with artificially injected signal. The injected signal is defined by a controlled feature set of variable parameters, including size, shape, and duration. OBJECTIVES: This report defines a flexible approach to evaluating public health surveillance systems for early detection of outbreaks and provides examples of its use. METHODS: The stages of outbreak detection are described, followed by the procedure for creating data sets for benchmarking performance. Approaches to setting parameters for simulated outbreaks by using controlled feature sets are detailed, and metrics for detection performance are proposed. Finally, a series of experiments using semisynthetic data sets with artificially introduced outbreaks defined with controlled feature sets is reviewed. RESULTS: These experiments indicate the flexibility of controlled feature set simulation for evaluating outbreak-detection sensitivity and specificity, optimizing attributes of detection algorithms (e.g., temporal windows), choosing approaches to syndrome groupings, and determining best strategies for integrating data from multiple sources. CONCLUSIONS: The use of semisynthetic data sets containing authentic baseline and simulated outbreaks defined by a controlled feature set provides a valuable means for benchmarking the detection performance of syndromic surveillance systems.

Disease Outbreaks↗
PubMed2005

[Outbreaks of norovirus gastroenteritis in nursing homes in Haifa, 2002-2003].

BACKGROUND: The incidence rate of Norovirus gastroenteritis is unknown since diagnostic tests are less readily available than for other agents. This pathogen is identified in less than 10% of acute gastrointestinal illness, despite the fact that recent reports from the United States attribute more than 50% of outbreaks to Noroviruses. OBJECTIVES: This article describes three outbreaks of gastroenteritis caused by Noroviruses in three of Haifa's chronic care hospitals in order to raise awareness of its main role as a common agent in such outbreaks, and thereby include it in the differential diagnosis of outbreak investigations. METHODS: Methods employed included epidemiological investigation of the outbreaks, sanitary inspection, personal interviews of hospital staff members, data collection from medical files and laboratory diagnosis by electron microscopy and RT-PCR of stool and vomitus for Noroviruses. RESULTS: Noroviruses were identified in faeces and vomitus of patients in 2 outbreaks in chronic care hospitals in Haifa. Attack rates were high (20-41%). Proximity in time to these 2 outbreaks, and clinical and epidemiological findings lead us to attribute another outbreak in a third hospital to norovirus as well. CONCLUSIONS: Physicians in institutions and the community should include Noroviruses in the differential diagnosis of outbreaks of gastroenteritis, particularly in cases where no other pathogens have been isolated. Timely requests for identification of Noroviruses are essential. The institution of good hygienic practices is important to prevent spread of this highly infectious agent.

Caliciviridae Infections↗
PubMed2005

Ambulatory-care diagnoses as potential indicators of outbreaks of gastrointestinal illness--Minnesota.

INTRODUCTION: Syndromic surveillance's capability to augment existing surveillance for community-acquired gastrointestinal disease is unknown. OBJECTIVE: The objective of this study was to evaluate the capability of a syndromic surveillance system to detect outbreaks of gastrointestinal disease. METHODS: A retrospective analysis was conducted comparing ambulatory care data from a health plan with a set of 110 gastrointestinal-disease outbreaks identified by the Minnesota Department of Health during 2001-02. Unusual clusters of illness (i.e., signals) in the health-plan data were identified by analyzing daily counts of gastrointestinal illness using an adjusted space-time scan statistic. Concordance was defined as < or =5 km between outbreak and signal and the signal occurring within 1 week of the outbreak. RESULTS: During 104 weeks, the number of signals was roughly what would have been expected by chance, suggesting that the modeling did a good job of estimating the expected counts of illness and that false alarms would not have occurred much more often than the number predicted at the various thresholds. During the same period, the health department identified 110 eligible gastrointestinal outbreaks. Apparent associations of the three statistically most unusual concordant signals with outbreaks of viral or bacterial gastrointestinal illness were ruled out by the health department on the basis of detailed knowledge of the circumstances and low numbers of affected persons seeking medical care. CONCLUSION: No previously known gastrointestinal outbreaks were identified by this surveillance system. However, relatively few recognized outbreaks resulted in patients seeking medical care, and the sensitivity of this system to detect outbreaks of real significance to public health remains to be determined. Prospective evaluation probably will be required to understand the usefulness of syndromic surveillance systems to enhance existing disease surveillance.

Ambulatory Care↗
PubMed2006

[Outbreaks of human rabies transmitted by vampire bats in Alto Baudó and Bajo Baudó municipalities, department of chocó, Colombia, 2004-2005].

INTRODUCTION: During months May to July 2004, a rabies outbreak in the Embera community of Birrinchao, in the Purricha river basin department of Choc6 was reported with 14 human deaths. Another rabies outbreak was reported in January 2005 in the black communities of Pató and Nauca in the neighboring municipality of Alto Baudó with 3 human deaths. OBJECTIVES: To describe the largest outbreaks of human rabies transmitted by vampire bats reported in Colombia to date. To describe the diagnostic laboratory techniques used, and the activities undertaken for the control of rabies in the area. To discuss the epidemiologic significance and public health implications of these rabies outbreaks. MATERIALS AND METHODS: Rabies diagnosis was achieved by direct immunofluorescence, inoculation of mice and immunohistochemistry. Typing of the virus was achieved by indirect immunofluorescence using monoclonal antibodies. Rabies control activities were undertaken in Bajo Baudó consisting in a population census, human vaccination and application of antirabies sera, vaccination of dogs and cats, and application of anticoagulant to bats. RESULTS: Four human cases were confirmed as positive for rabies in both rabies outbreaks. Another 13 rabies cases in humans were inferred by strong epidemiological links. Rabies antigenic variant 3 was identified in the samples studied. Rabies control activities were conducted for a human rabies outbreak caused by vampire bats. CONCLUSIONS: The human rabies outbreak in Bajo Baudó has been the largest reported in Colombia. It was caused by vampire bats, showing that these animals are a threat for human health. The implementation of control strategies for this kind of epizootic outbreaks is needed in South America. It remains unknown whether there is a link between this outbreak and one reported 6 months later in the neighboring municipality of Alto Baudó.

Adolescent↗
PubMed1995

Serogroup C meningococcal outbreaks in the United States. An emerging threat.

OBJECTIVE: Multiple outbreaks of serogroup C Neisseria meningitidis have recently been reported from diverse areas of the United States. To better define the characteristics of this increasingly important problem, we reviewed data on all known serogroup C outbreaks in the United States from January 1980 through June 1993. DATA SOURCES: MEDLINE searches, Centers for Disease Control and Prevention records, state health department officials, infectious disease experts, and the meningococcal vaccine manufacturer. DEFINITION OF AN OUTBREAK: Three or more cases of serogroup C meningococcal disease within a 3-month period, either among members of a community or persons attending a single school or other institution, for which those cases represented an attack rate of at least five per 100,000 population. RESULTS: Twenty-one outbreaks of serogroup C meningococcal disease were identified; eight occurred since 1991. In 1992 and the first half of 1993, approximately 180,000 doses of vaccine were administered for outbreak control, compared with approximately 34,000 doses from 1980 to 1991. Approximately 50% of community-outbreak cases were between the ages of 5 and 24 years, compared with only 19% of sporadic serogroup C cases (P < .001). Subtyping of patient isolates indicates that outbreaks are clonal; however, at least five distinct but closely related strains have caused recent outbreaks. CONCLUSIONS: Serogroup C outbreaks are occurring more frequently in the United States. The effectiveness of preventive measures depends on early recognition; therefore, physicians should promptly report all cases of suspected meningococcal disease, and the causative serogroup should be established for every case.

Adolescent↗
PubMed1996

Community-based outbreaks of tuberculosis.

Numerous recent reports have detailed outbreaks of tuberculosis in hospitals and other congregate settings. The characteristics of such settings, including high concentrations of infectious patients and immunocompromised hosts, the potential for sustained daily contact for weeks and often months, and improper precautions taken for protection, make them well suited for tuberculosis transmission. However, community-based outbreaks, which are the source of much public concern, have not been reviewed since 1964, when 109 community outbreaks were examined. Since few of the characteristics of institutional settings are present in the community, the lessons learned may not be applicable to community-based outbreaks. Furthermore, recent studies with analysis by restriction fragment length polymorphisms have documented unexpectedly high rates of primary disease in certain urban communities, suggesting that our understanding of community-based transmission may be incomplete. We reviewed all reported community-based outbreaks of tuberculosis occurring in the last 30 years to assess the basis of our current understanding of community-based transmission. More than 70 outbreaks were identified, with schools being the most common site. In most, a delay in diagnosis, sustained contact with the index case, inadequate ventilation, or overcrowding was contributory. We conclude that community-based outbreaks of tuberculosis continue to occur and that well-established risks contribute to most outbreaks. Many outbreaks can be prevented or limited by attention to basic infection control principles.

Community-Acquired Infections↗
PubMed1997

Control and prevention of serogroup C meningococcal disease: evaluation and management of suspected outbreaks: recommendations of the Advisory Committee on Immunization Practices (ACIP).

Outbreaks of serogroup C meningococcal disease (SCMD) have been occurring more frequently in the United States since the early 1990s, and the use of vaccine to control these outbreaks has increased. These outbreaks are characterized by increased rates of disease among persons who may have a common organizational affiliation or who live in the same community. By using surveillance for SCMD and calculation of attack rates, public health officials can identify SCMD outbreaks and determine whether use of meningococcal vaccine is warranted. This report describes 10 steps for evaluation and management of suspected SCMD outbreaks. The principles described also apply to suspected outbreaks caused by meningococcal serogroups A, Y, and W-135. The effectiveness of mass chemoprophylaxis (administration of antibiotics to large populations) has not been demonstrated in most settings in which community and organizational outbreaks occur. However, in outbreaks involving small populations, administration of chemoprophylaxis to all persons within this group may be considered. The ability to validate some aspects of these recommendations is currently limited by incomplete reporting of serogroup information in most systems for meningococcal disease surveillance in the United States and by the relative rarity of SCMD and SCMD outbreaks.

Antibiotic Prophylaxis↗
PubMed2005

Multistate outbreak of Listeriosis linked to turkey deli meat and subsequent changes in US regulatory policy.

BACKGROUND: Listeriosis, a life-threatening foodborne illness caused by Listeria monocytogenes, affects approximately 2500 Americans annually. Between July and October 2002, an uncommon strain of L. monocytogenes caused an outbreak of listeriosis in 9 states. METHODS: We conducted case finding, a case-control study, and traceback and microbiological investigations to determine the extent and source of the outbreak and to propose control measures. Case patients were infected with the outbreak strain of L. monocytogenes between July and November 2002 in 9 states, and control patients were infected with different L. monocytogenes strains. Outcome measures included food exposure associated with outbreak strain infection and source of the implicated food. RESULTS: Fifty-four case patients were identified; 8 died, and 3 pregnant women had fetal deaths. The case-control study included 38 case patients and 53 control patients. Case patients consumed turkey deli meat much more frequently than did control patients (P = .008, by Wilcoxon rank-sum test). In the 4 weeks before illness, 55% of case patients had eaten deli turkey breast more than 1-2 times, compared with 28% of control patients (odds ratio, 4.5; 95% confidence interval, 1.3-17.1). Investigation of turkey deli meat eaten by case patients led to several turkey processing plants. The outbreak strain was found in the environment of 1 processing plant and in turkey products from a second. Together, the processing plants recalled > 30 million pounds of products. Following the outbreak, the US Department of Agriculture's Food Safety and Inspection Service issued new regulations outlining a L. monocytogenes control and testing program for ready-to-eat meat and poultry processing plants. CONCLUSIONS: Turkey deli meat was the source of a large multistate outbreak of listeriosis. Investigation of this outbreak helped guide policy changes designed to prevent future L. monocytogenes contamination of ready-to-eat meat and poultry products.

Adolescent↗