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PubMed1983

Outbreaks of diarrhea associated with Clostridium difficile and its toxin in day-care centers: evidence of person-to-person spread.

Clostridium difficile was associated with five outbreaks of diarrhea occurring in three day-care centers caring for children less than 2 years of age during a three and one-half-month period; two centers had one outbreak of diarrhea, and one had three outbreaks. The frequency of isolation of C. difficile and its toxin was determined in stool specimens from 65 children attending the three day-care centers. Twelve of 21 (57%) children who had diarrhea excreted C. difficile and its toxin, whereas only four of 44 (9%) children who did not experience diarrhea yielded the organism and the toxin. Five of the 12 symptomatic children with C. difficile and its toxin had received prior antimicrobial therapy for upper respiratory tract infections. An eight-month prospective study was then carried out in one room of the center where the three outbreaks had occurred. Initially, one child had culture-positive stools for C. difficile. During the first 13-week study period six additional children of the 12 (50%) in the room under study became colonized with C. difficile. Six of the seven children who excreted C. difficile and its toxin experienced diarrhea with C. difficile toxin-positive stools by the end of the 13 weeks. Environmental contamination increased as more children became colonized and developed diarrhea. Electrophoretic evaluation of environmental and stool isolates obtained during one outbreak of diarrhea showed that the isolates had an identical protein pattern. Findings of this study indicate the importance of searching for C. difficile in children in day-care centers who develop diarrhea.

Bacterial Toxins↗

PubMed1987

A nursery outbreak of group A streptococcal infection.

We report an outbreak of 23 neonatal group A streptococcal infections including two cases of septicaemia in a nursery for the newborn. At the same time, 19 mothers had puerperal endometritis. The outbreak lasted for about 2 months and could not be eradicated by ordinary hygienic measures. In a colonisation study, 19 of 90 umbilical stumps studied on the day of discharge from hospital harboured group A streptococci, all of the same epidemic strain T28 provisional M-type 2841/opacity factor positive (T28/MPT2841/OF+). Chlorhexidine gluconate was therefore applied daily to the umbilical stumps. The outbreak came to an end with the introduction of this procedure. The time interval between delivery and recognition of infection was shorter in infants than in mothers. There were also only two infected mother-infant pairs. Taken together, this suggests that infected umbilical stumps on symptomless infants were a likely source of the maternal infections. Throughout 1 year from the introduction of the chlorhexidine treatment, we have not seen a case of group A streptococcal infection in neonates. Surveillance cultures from umbilical cords after the outbreak have also been negative. We conclude that bacteriological surveillance of umbilical stumps is valuable in recognising an outbreak and should be seriously considered when a group A streptococcal infection has been recorded in a nursery.

Disease Outbreaks↗

PubMed1989

The presence of M proteins in outbreak strains of Streptococcus equisimilis T-type 204.

Cultures of Streptococcus equisimilis (Lancefield group C) from three outbreaks of illness were found to carry the T-protein antigen 204. Strains of this type were not otherwise represented in a collection of 743 cultures of these 'pyogenes-like' streptococci isolated from other outbreaks of infection or as random isolates. Two of the three outbreaks were of pharyngitis. The third arose in a maternity unit where the organism was isolated from mothers with puerperal fever, from staff and also from the environment. Representative strains were found to carry M-protein antigens as judged by their ability to survive and multiply in fresh normal human blood. Comparison of absorbed rabbit antiserum to the M antigens in opsonic and precipitin tests showed that a distinct M antigen was present on isolates from one outbreak of sore throat and that all cultures from the other two incidents shared a common M antigen. Samples of serum were also available from patients in the outbreak of puerperal sepsis. Most patients developed antibodies to one or more streptococcal antigens including the M protein, streptolysin O, streptokinase and the hyaluronidase specific for strains of group C and group G streptococci.

Antigens, Bacterial↗

PubMed1992

Measles: lessons from an outbreak.

BACKGROUND: Measles outbreaks continue to be a problem for infection control in hospitals--patients, personnel, and employee health service. Guidelines for measles outbreaks are not clear for medical personnel in the hospital. METHODS: Outbreak investigation in a university-affiliated teaching hospital. RESULTS: Four primary cases resulted in 607 staff exposures and two secondary cases. Forty-seven medical personnel were furloughed and 88 were vaccinated for measles. Minimal serologic criteria for immunity were found to be inadequate in the outbreak setting. CONCLUSIONS: We found that serologic guidelines for assessing immunity to measles are inadequate. During the outbreak, we arbitrarily doubled the acceptable enzyme-linked immunosorbent assay titers that we would consider protective, > or = 2, to decrease the possibility of further secondary cases. Employees with enzyme-linked immunosorbent assay measles titers less than 2 and without a definite history of natural measles were revaccinated with a measles vaccine. This strategy takes advantage of the anamnestic response that revaccination would confer in persons with low antibody titer.

Adult↗

PubMed2025

Investigation of a Mycobacterium fortuitum prosthetic joint infection outbreak at two ambulatory surgery centers in Tennessee.

OBJECTIVE: This study outlines the investigation into an outbreak of Mycobacterium fortuitum infections involving 17 cases undergoing hip or knee surgeries at two ambulatory surgery centers (ASCs) in Tennessee from January 2023 to November 2024. Notably, the outbreak could not be attributed to contaminated water sources, which are typically associated with non-tuberculous mycobacteria (NTM) outbreaks, presenting a unique challenge. METHODS: Outbreak investigation steps included Infection Prevention (IP) assessments, case-control study, environmental sampling, whole genome sequencing, and a healthcare personnel (HCP) exposure questionnaire. RESULTS: IP assessment highlighted several concerns, including no formal facility water management program (WMP), a lack of dedicated IP personnel and certified sterile processing staff, the absence of a formalized system for tracking surgical site infections, and a notable gap in understanding the requirements for reporting diseases. The case-control findings revealed a significant association between the presence of a surgical technologist in the operating room during the procedures and the occurrence of NTM infections, indicated by an odds ratio of 55.77 (95% CI [3.16-985.44]; P = 0.0097). Thirteen clinical isolates collected at one ASC and three additional isolates collected at a second ASC were highly related by whole genome sequencing. CONCLUSION: The study further elucidates valuable insights gained from the outbreak response, including the gaps in surveillance within the ambulatory surgical setting and systematic collection of cultures from environmental sources. It emphasizes the importance of thorough vetting, onboarding, continuing education, and practice monitoring for HCP.

Humans↗

PubMed1980

Application of serological typing to the investigation of outbreaks of Clostridium perfringens food poisoning, 1970-1978.

Serological typing was used as an epidemiological tool in the investigation of 524 outbreaks of Clostridium perfringens food poisoning in the United Kingdom and 37 outbreaks in other countries. Five thousand five hundred and fifty-four (77%) of 7245 strains of C. perfringens associated with the 561 outbreaks were typable with the 75 Food Hygiene Laboratory antisera; in 354 (63%) of these outbreaks a specific serotype was established as being responsible for the outbreak. An assessment is made of the ability of two additional sets of antisera, prepared against 34 American and 34 Japanese strains of C. perfringens, to increase the number of strains which can be typed. The extent of cross-reaction between the three sets of antisera was determined and the results are discussed in relation to the source and history of the type strains.

Clostridium Infections↗

PubMed1990

DNA restriction digest and ribosomal RNA gene patterns of Campylobacter jejuni: a comparison with bio-, sero-, and bacteriophage-types of United Kingdom outbreak strains.

DNA restriction endonuclease (Hae III and Hind III) total digest and 16S and 23S ribosomal (r)RNA gene patterns (ribopatterns) were determined for 18 isolates of Campylobacter jejuni from three separate outbreaks of diarrhoea in the north of England. Strains were also characterized by biotyping, serotyping and phage typing. Comparisons of the DNA patterns by visual and numerical methods revealed five distinct strain groupings with clear differences between isolates from different outbreaks as well as some heterogeneity between strains within the community outbreak and one of the school outbreaks. An excellent correlation was observed between the genomic DNA fingerprints data and the Preston bacteriophage group, both of which gave better discrimination than biotyping and serotyping alone or in combination. Only one phage group (PG 37) was not confirmed by the DNA data. DNA fingerprints therefore provide additional information of value in studying the epidemiology of outbreaks of C. jejuni.

Animals↗

PubMed1991

Variation in time and space of non-outbreak Legionnaires' disease in Scotland.

The main aim of this study was to measure and explain geographic variations in the incidence of Legionnaires' disease in Scotland, particularly to help understand the source of non-outbreak infection. Between 1978 and 1986 the overall mean annual incidence rate was 7.9 per million (range 3.1-20.2), and for non-outbreak, non-travel cases it was 5.6. There were geographical variations by health board, by city and within cities, e.g. the mean annual incidence rate per million for non-travel, non-outbreak disease was 1.2 in Tayside Health Board, 3.7 in Lanarkshire, 5.6 in Lothian and 14.4 in Greater Glasgow. In Greater Glasgow Health Board non-travel cases lived in and around the city centre and in some postcode sectors there, the mean annual incidence rate exceeded 100. Travel-related cases lived in peripheral areas. These variations could not be explained by differences in access to and use of diagnostic services, surveillance, or host susceptibility (as reflected by socioeconomic status and frequency of other respiratory disease). The explanation probably lay in environmental factors, though differences in agent virulence were not excluded. The two main conclusions are, that non-outbreak cases were not truly sporadic, and that the space-time variations in incidence support the hypothesis that cooling towers were an important source of infection for non-travel, non-outbreak cases. If so such infection is potentially preventable.

Adolescent↗

PubMed2026

Emergence of a Bundibugyo virus variant in the 2026 outbreak in the Democratic Republic of the Congo and Uganda.

In May 2026, an outbreak of Ebola disease caused by Bundibugyo virus (BDBV, species Orthoebolavirus bundibugyoense) was declared in the Democratic Republic of the Congo (DRC), with cases originating from DRC and locally transmitted cases reported in Uganda. Bundibugyo virus disease (BVD) outbreaks were previously recorded in 2007-2008 in Bundibugyo District, Uganda, and in 2012 in Isiro, DRC. Here, we generated 22 genomes from samples obtained from individuals with BVD in DRC and Uganda. These genomes form a well-supported phylogenetic cluster separate from BDBV variants associated with the 2007 and 2012 outbreaks, together with evidence for sustained human transmission. This is consistent with the emergence of a new zoonotic spillover event rather than resurgence from previously reported variants. Besides ongoing efforts in strengthening surveillance systems, community engagement, establishing Ebola treatment centers, and developing targeted medical countermeasures; our report advocates to specifically increase decentralized laboratory diagnostics capacity, with pan-Orthoebolavirus assays, including genomic sequencing capacity, for limiting further outbreak expansion, timely detection and control of future outbreaks.

Journal Article↗

PubMed1991

Analysis of historical epidemiological data to guide intervention policy in the face of an infectious disease outbreak: poliomyelitis in Israel in 1988.

During the 1988 outbreak of 15 cases of Type 1 poliomyelitis mainly among previously vaccinated young adults in Israel, there were conflicting views on the need for and timing of mass vaccination. Since there was a possibility that the initially localized outbreak may spread more widely, it was felt that an early decision on vaccination policy should be made. Public health officials were faced with varied interpretations of the existing data on the extent of the immune status of the population; some indicating that as many as 15% of young adults lacked immunity to the Type 1 virus. Two major questions posed were whether or not the outbreak was a purely localized event in a single subdistrict, and whether the seasonality of the disease would limit its spread. Based on historical data, probability analysis of three cases occurring outside the subdistrict at the time of the outbreak suggested more widespread dispersion of the virus. Further analysis indicated very limited seasonality of the disease in this region, suggesting that the onset of colder weather would have little impact on the spread of the virus. Careful analysis of the local epidemiology of the disease is an important tool for guiding urgent decisions on mass intervention policy in outbreak situations.

Adolescent↗

PubMed1988

A large outbreak of mumps in the postvaccine era.

During a county-wide mumps outbreak in Nashville, Tennessee, 332 cases of mumps were identified at a public high school (attack rate, 18.8%). A pep rally 17 d before the peak of the outbreak at a single public high school may have provided an opportunity for point-source exposure. A case-control study demonstrated that vaccine efficacy was 75% (we used provider-verified records and excluded students with a history of mumps disease). Although school records were nonuniform, mumps immunization status was correct, compared with provider-verified records, in at least 85% of both cases and controls. Parental reports were much less reliable. The cost of the outbreak was estimated at $154/case. Receiving mumps vaccine at a vaccine clinic held after the outbreak had peaked was associated with a decrease in risk of mumps disease. Thus, these clinics may have a role in the control of such outbreaks.

Adolescent↗

PubMed1990

A large outbreak of antibiotic-resistant shigellosis at a mass gathering.

In July 1987, a large outbreak of shigellosis occurred among attendees at a mass gathering in a national forest, the annual Rainbow Family Gathering. Sanitation in the campsite was poor, allowing widespread transmission of disease, probably by food, water, and person-to-person spread. The attack rate may have been greater than 50% among the estimated 12,700 attendees. The outbreak was caused by Shigella sonnei, resistant to ampicillin, tetracycline, and trimethoprim-sulfamethoxazole; the organism was of colicin type 9 and contained a 90-kilobase plasmid not found in non-outbreak-related strains. The dispersal of the group resulted in nationwide dissemination of the organism, and outbreaks in three states were linked to transmission from attendees at the Gathering. This outbreak demonstrates the potential for rapid dissemination of disease in such a setting and the necessity for careful planning of mass gatherings.

Age Factors↗

PubMed2026

Nosocomial Outbreak of Lassa Fever in Conakry, Guinea, 2022.

BACKGROUND: Lassa fever is endemic in Guinea, with high seroprevalence in the forest region. However, clinical cases have been only anecdotally reported. In August 2022, a nosocomial outbreak occurred at a private clinic in the capital, Conakry, an area previously considered low risk. METHODS: Suspected cases were confirmed by real-time reverse-transcription polymerase chain reaction within 24 hours. Viremia was monitored during hospitalization, and whole-genome sequencing was performed in-country within 13 days of outbreak detection. Outbreak investigation involved rodent testing in the home village of the suspected primary case. RESULTS: Six cases were laboratory-confirmed, 5 of which were healthcare workers of the clinic. The case fatality rate was 16.7%. Viral RNA remained detectable in blood of survivors for a median of 26 days (interquartile range, 24-41 days) post-disease onset. Epidemiological investigations identified a suspected primary case, who had died of a febrile disease compatible with Lassa fever, had contact with all secondary cases, and had a travel history from Kissidougou area. Three near-complete and 1 partial Lassa virus genomes were recovered from the secondary cases, which phylogenetically clustered with genomes from central Guinea. Consistent with a common transmission source, the 4 genomes were almost identical. Rodent testing revealed a new reservoir area in eastern-central Guinea. CONCLUSIONS: This outbreak highlights the vulnerability of healthcare settings in low-prevalence areas of West Africa to nosocomial Lassa virus transmission due to human mobility. Facilitated by capacity-building programs for viral hemorrhagic fevers, rapid diagnosis, genomic analysis, and ecological assessment enabled an efficient outbreak response and control.

Lassa Fever↗

PubMed1984

Legionnaires' disease: the epidemiology of two outbreaks in Burlington, Vermont, 1980.

Eighty-five cases of Legionnaires' disease were diagnosed in two major outbreaks at a large regional medical center in Burlington, Vermont, in the summer of 1980. Cases in both outbreaks were positive for Legionella pneumophila, serogroup 1 by culture, serology, or direct fluorescent antibody tests. All cases had spent time in the city of Burlington in the 10 days before the onset of symptoms. Cases in both outbreaks were both hospital- and community-acquired. A case-control study identified no common in-hospital exposure, including shower use, that was associated with illness. Cases without previous exposure to the hospital were more likely to occur in persons with residences in neighborhoods just downwind of cooling tower A, but not throughout the municipal water system. Epidemiologic and environmental studies supported the association of this cooling tower, located 150 m from the hospital, with both outbreaks. Maintenance employees who worked with tower A had higher Legionella titers than those who worked with a comparison tower located 1.6 km away. Aerosolization of L. pneumophila by tower A and airborne spread to the hospital and community are postulated. The distance of airborne transmission of L. pneumophila in these consecutive outbreaks is greater than previously reported.

Cross Infection↗

PubMed1985

Continuing measles transmission in students despite school-based outbreak control program.

FRom September 9, 1981 to January 5, 1982, a measles outbreak occurred in Warren County, Pennsylvania. The outbreak persisted for nine weeks following the implementation of a county-wide outbreak control program primarily consisting of identifying and vaccinating susceptible schoolchildren. Forty-six cases occurred among students more than two weeks after control program implementation. All 46 had a school record indicating adequate measles vaccination; 13 had been vaccinated at control program clinics by one jet-injector team (Team A). A seroprevalence survey demonstrated that persons vaccinated by Team a had a significantly higher rate of vaccination failure than children vaccinated by other teams (37.0% vs. 5.9%, p = 5.7 X 10(-7). A case-control study was undertaken to assess possible additional risk factors for developing measles. Individuals with measles were nine times more likely than control individuals to have records of measles immunization that could not be verified with providers or to have been vaccinated at 12 months of age. The most likely reasons that this outbreak was sustained among persons with adequate vaccination histories were: 1) impotent vaccines and/or improper vaccine administration techniques were used by one jet-injector team; 2) several persons with histories of adequate vaccination were really not adequately vaccinated; adn 3) a substantial number of persons had been vaccinated at 12 months of age. There is no evidence from this outbreak that transmission of measles can be sustained among the 2-10% of individuals expected to remain susceptible following a single appropriate measles vaccination.

Adolescent↗

PubMed1986

Contaminated produce--a common source for two outbreaks of Shigella gastroenteritis.

Simultaneous outbreaks of Shigella sonnei gastroenteritis occurred in October 1983 at two Texas university campuses 60 miles (96 km) apart. There were no common food handlers, recreational activities, water sources or swimming areas to explain the introduction of Shigella at both campuses. However, tossed salads were found to be associated with illness at both campuses. The investigation disclosed that both schools had received produce shipments from the same company during the week preceding these outbreaks. Shigella isolates from cases at both universities, sent to the Centers for Disease Control for plasmid analysis and colicin typing, were found to be identical. The same organism was evidently not a frequent cause of shigellosis within a 160-mile (256 km) radius of these universities since only 19% of control isolates chosen from this area were identical to the type which caused these outbreaks. This is the first report of two related outbreaks of shigellosis that were caused by a contaminated food source and not by a food handler. Simultaneous foodborne outbreaks of shigellosis should trigger a search for potential contamination at every step of food handling from farm to kitchen.

Disease Outbreaks↗

PubMed1987

Salmonellosis outbreak on transatlantic flights; foodborne illness on aircraft: 1947-1984.

In March 1984, 186 cases of gastroenteritis due to Salmonella enteritidis were reported after 29 flights to the United States on an international airline. An estimated 2,747 passengers on flights to the United States were affected. Illness was associated with flying supersonic or first class (odds ratio = 15, p less than 0.001). Eating food from the first-class menu was associated with illness (p = 0.09), and eating a tourist-class entree was protective (p less than 0.01). In 23 reported outbreaks of foodborne illness on aircraft, Salmonella has been the most common pathogen (seven outbreaks), followed by Staphylococcus (five outbreaks), and Vibrio species (five outbreaks). Outbreaks are most often the result of an improper temperature for preparation or for holding food in the flight kitchens. Serving the flight crew meals from one kitchen carries the risk that the entire crew will become ill.

Aircraft↗

PubMed1987

A cost-effectiveness analysis of measles outbreak control strategies.

This study compares the cost-effectiveness of six vaccination strategies during a measles outbreak: vaccination of all susceptibles 15 months of age or older and born after 1956 (the current routine strategy); lowering the recommended age at vaccination from 15 to 12 months (plus current routine strategy); lowering the recommended age at vaccination to six months (plus current routine strategy); revaccination of those vaccinated at 12-14 months of age (plus current routine strategy); vaccination of all students in school regardless of immune status; and vaccination of all residents 15 months to 28 years of age in the community regardless of immune status. The analysis is based on the hypothetical, early application of these strategies to a 1985 measles outbreak in Montana, which occurred despite appropriate application of current prevention and control recommendations. Although the results are applicable only to this particular outbreak, this analysis provides an approach which can be used in other settings to assess measles outbreak control strategies. Similar studies would need to be performed in a variety of settings to determine the most cost-effective measles outbreak control strategies overall.

Child↗