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PubMed1995

Interrepeat fingerprinting of third-generation cephalosporin-resistant Enterobacter cloacae isolated during an outbreak in a neonatal intensive care unit.

OBJECTIVE: To investigate an outbreak in neonates of Enterobacter cloacae infection resistant to third-generation cephalosporins. DESIGN: A retrospective study of an outbreak in the neonatal intensive care unit (NICU) and review of E cloacae isolates in pediatric wards and other intensive care units from June 1992 through March 1993. SETTING: An academic tertiary care hospital. PATIENTS: Six patients admitted to the NICU were colonized or infected with E cloacae resistant to third-generation cephalosporins. In the period preceding the outbreak, four E cloacae isolates were available from four patients in the pediatric surgical ward. Nine isolates from four patients in two other intensive care units (ICUs) also were collected during the outbreak. Isolates were biotyped by the API 50CH system and genotyped by polymerase chain reaction (PCR) fingerprinting. RESULTS: Typing by interrepeat PCR showed that 21 isolates, which were obtained from five neonates, were identical. One neonate was colonized with a different strain. Some neonates were colonized with a single type of E cloacae for a relatively long period of time. Isolates of patients who were cared for in the pediatric surgical ward and the two other intensive care units (ICUs) showed different genotypes. One patient in an ICU was colonized with an E cloacae strain genetically identical to the outbreak strain. No predominant biotype could be established. CONCLUSIONS: E cloacae can colonize neonates for a long period of time and although colonization with E cloacae initially may arise endogenously, we were able to show further transmission by cross-contamination in a neonatal intensive care unit.

Bacterial Typing Techniques↗

PubMed1999

Influenza outbreak in a long-term-care facility: considerations for pharmacy.

The role played by a hospital pharmacy department in managing an influenza outbreak at an affiliated long-term-care facility is described. In February 1998 an outbreak of influenza A was confirmed in a 570-bed long-term-care facility. During the outbreak, a total of 48 cases of influenza-like illness (ILI) were reported to infection control, and 62 staff members missed work because of ILI. Infection control measures included a recommendation for prophylaxis with amantadine. Pharmacists assumed responsibility for educating patients and families about amantadine prophylaxis, providing individualized dosing, evaluating reported adverse effects, and drug distribution. Pharmacists developed an information sheet on amantadine for patients and met with patients and their families. The overall acceptance rate for chemoprophylaxis was 91%. Of the 349 patients receiving amantadine during the outbreak, 203 (58%) were given 100 mg daily, 136 (39%) were given 100 mg every other day, and 10 (3%) were prescribed 100 mg weekly. Pharmacists confirmed a total of 22 adverse effects; generally the problem was solved by reducing the dosage rather than discontinuing the drug. In all cases, the first dose of amantadine was provided to the nursing units within three hours of an order being written. Pharmacists played an active role in managing an influenza A outbreak at a long-term-care facility.

Aged↗

PubMed1995

Concurrent outbreaks of pertussis and Mycoplasma pneumoniae infection: clinical and epidemiological characteristics of illnesses manifested by cough.

Concurrent outbreaks of illnesses that were manifested by cough and that were suspected to be due to Bordetella pertussis and Mycoplasma pneumoniae infection were investigated in a midwestern town in Illinois. Three studies were conducted: questionnaires on the clinical and epidemiological characteristics of illness were administered to patients; serological tests were performed to confirm the presence of each pathogen and to develop case definitions for each illness; and case definitions were applied to responses to a mail-in questionnaire for estimating the magnitude of both outbreaks. In 135 cases of suspected pertussis and 42 cases of suspected mycoplasmal infection, subjects had a cough for > or = 14 days (the pertussis outbreak case definition). Among 20 laboratory-confirmed cases, a cough for > or = 14 days had a specificity of 20% for pertussis, and a cough for > or = 28 days plus whoop and/or vomiting had a specificity of 90% for pertussis. Six hundred-seventeen pertussis cases per 100,000 population and 1,179 cases of M. pneumoniae infection per 100,000 population occurred. In this setting, the standard outbreak case definition for pertussis lacked adequate specificity to distinguish pertussis from mycoplasmal infection. The magnitude of each outbreak was greater than the number of reported cases suggested.

Adolescent↗

PubMed2001

Public health management of an outbreak of group C meningococcal disease in university campus residents.

BACKGROUND: Increasing numbers of outbreaks of Group C meningococcal disease in teenagers and young adults led to a new policy in the UK in 1999 of vaccinating all new college students. The largest of these outbreaks involved seven students in one university, six of whom were from one hall of residence, and two of whom died. METHODS: Control of the outbreak involved close medical surveillance of resident students, mass chemoprophylaxis and vaccination, and wide dissemination of daily information bulletins. Investigation of the epidemiology of the outbreak involved searching for the network of close contacts between cases, a prevalence survey of carriage of meningogocci and a case control study of risk factors for carriage. RESULTS: Clinical cases could be linked by a discrete network of social contacts within the halls of residence, but the Group C epidemic strain (2a P1.5) was not detected in 454 students (upper 95% confidence interval 0.7%). Carriage of any meningococcal strain (19%) was associated with patronage of the campus bar (OR = 3.0, 0.99-9.1). CONCLUSION: Important factors in the control of the outbreak were rapid institution of mass chemopropylaxis and immunisation of residents, and involvement of student organizations in the dissemination of information about the disease and its control. The role of campus bars in dissemination of the carriage of meningogocci deserves further investigation.

Adolescent↗

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↗

PubMed1994

A 'post-honeymoon period' measles outbreak in Muyinga sector, Burundi.

In Muyinga sector, Burundi, an area with good vaccination levels against measles and recent low incidence of measles, a major outbreak of measles in 1988 raised questions about the efficacy of the immunization programme. To help answer these questions, we 1) reviewed programme data on doses of measles vaccine administered, vaccine coverage, and measles incidence, and 2) conducted a census of the affected area to examine vaccine efficacy and measles mortality. We found that between 1980 and 1988 in Burundi, 1) measles vaccine coverage by age 1 had increased from 0% to 55%, 2) the incidence of reported measles cases declined from 12.1/1000 to 6.2/1000, 3) reported measles mortality dropped from 0.18/1000 to 0.08/1000, and 4) the interepidemic period had increased from 25 to 35 months. In the census, the best estimate of measles vaccine efficacy administered at 9 months of age was 73%. Measles increased the risk of death by 2.5-fold with the effect limited to the first month after measles. This outbreak demonstrated the 'post-honeymoon period' epidemic predicted by mathematical models in which outbreaks occur among accumulated susceptibles in a partially immunized population. Understanding this phenomenon is important in providing a basis for improved strategies of measles control. Such outbreaks present new challenges to newly maturing immunization programmes in improving skills in surveillance, outbreak investigation, and public relations.

Burundi↗

PubMed2000

Outbreak of Legionnaires' disease associated with a display whirlpool spa.

BACKGROUND: Recognized outbreaks of Legionnaires' disease (LD) are rare; when they occur, they provide opportunities to understand the epidemiology of the illness and improve prevention strategies. We investigated a population-based outbreak. METHODS: After the confirmation of LD in October 1996 in five people in neighbouring towns in southwest Virginia, active surveillance for additional cases was undertaken. A case-control study was conducted to identify exposures associated with illness, followed by a cohort study among employees of the facility at which the source of the outbreak was located in order to assess unrecognized exposure and illness. Samples of likely sources of LD in the facility were cultured for LEGIONELLA: RESULTS: In all, 23 laboratory-confirmed cases of LD were eventually identified. Of the 15 cases in the case-control study, 14 (93%) reported visiting a home-improvement store, compared with 12 (27%) of 45 controls (matched odds ratio [MOR] = 23.3; 95% CI : 3-182). Among home-improvement centre patrons, 10 (77%) of 13 cases questioned recalled either visiting or walking by a display whirlpool spa, compared with 3 (25%) of 12 controls (MOR = 5.5; 95% CI : 0.7-256.0). Two cases' sputum isolates were an exact match, by monoclonal antibody subtyping and arbitrarily primed polymerase chain reaction, to a whirlpool spa filter isolate from the store. Employees reporting more exposure to the display spas were more likely to report symptoms of LD or to have an elevated titre. CONCLUSIONS: This investigation shows that LD can be transmitted from a whirlpool spa used for display only, and highlights the need for minimizing the risk of transmission of LD from all water-filled spas. Key messages This paper describes an investigation of a population-based outbreak of Legionnaires' disease (LD). A case-control study first identified a home-improvement store as the likely source of the outbreak. An environmental investigation later confirmed that finding, as two cases' sputum isolates were an exact match, by monoclonal antibody subtyping and arbitrarily primed polymerase chain reaction, to a whirlpool spa filter isolate from the store. The spa was intended and used for display only.

Adult↗

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↗

PubMed2005

Analysis of Barmah Forest virus disease activity in Queensland, Australia, 1993-2003: identification of a large, isolated outbreak of disease.

Barmah Forest virus (BFV) disease is the second most common mosquito-borne disease in Australia. Although the majority of notifications are received from Queensland, little is known about the distribution of the disease within the state, or the important mosquito vectors and nonhuman vertebrate hosts. We conducted a retrospective statistical analysis of the notifications received from Queensland residents from 1993 to 2003 to establish long-term local incidence rates and to identify disease outbreaks. In total, 4,544 notifications were received over the 10-yr period. Disease reporting peaked in autumn, although the peak transmission season encompassed both summer and autumn. Long-term standardized incidence rates for summer/autumn and winter/spring varied across the state, showing positive spatial autocorrelation in both 6-mo periods. Although 15 instances of increased disease activity were identified, only one major disease outbreak affecting eight contiguous local government areas was detected in summer/autumn 2002/2003. This outbreak contained 297 cases, 115 more than would be expected over this period. The factors important to this outbreak are unknown and require further investigation. Although the incidence rates for BFV disease are lower than Ross River virus disease, the most reported mosquito-borne disease in Australia, several factors indicate that this virus should be considered an important public health risk in Queensland. These include consistent endemic transmission, apparent underreporting of the disease, and the potential for outbreaks in major population centers.

Alphavirus Infections↗

PubMed1980

Waterborne giardiasis: a communitywide outbreak of disease and a high rate of asymptomatic infection.

A communitywide outbreak of gastrointestinal illness due to Giardia lamblia infection occurred in the city of Berlin, New Hampshire, during April and May 1977. The clinical, epidemiologic, and laboratory aspects of this outbreak are described here. In 213 predominantly symptomatic cases of G. lamblia infection diagnosed at a local hospital laboratory in a 6-week period, illness was characterized by prolonged diarrhea (median duration 10 days) and 13% of symptomatic infections required hospitalization. Treatment with either quinacrine or metronidazole was generally followed by symptomatic improvement. A communitywide survey of the city residents revealed that the majority (76%) of G. lamblia infections occurring during the epidemic period were asymptomatic and ran a self-limited course without treatment. No significant secondary, person-to-person spread occurred and no enteric pathogens other than G. lamblia were implicated. Water was epidemiologically implicated as the most likely source of infection with Giardia cysts being demonstrated in samples of treated water as well as raw source water. Evidence supported the occurrence of two simultaneous outbreaks in this city which is supplied by two largely independent water supply systems. Inspection of the two water treatment facilities revealed several defects which permitted untreated (raw) water to mix with treated water. Human or beaver could have been responsible for contaminating source water with Giardia in this outbreak. A marked reduction in both clinical and subclinical giardiasis was apparent two months after onset of the outbreak, apparently as a result of measures applied to interrupt waterborne transmission of Giardia.

Adolescent↗

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↗

PubMed1988

A shigellosis outbreak traced to commercially distributed shredded lettuce.

In the period August 30-October 7, 1986, 347 persons in adjacent west Texas counties (Ector and Midland) contracted culture-confirmed Shigella sonnei gastroenteritis. A case-control study showed an increased risk of acquiring shigellosis in Ector County with eating at outlets of fast-food Restaurant A, and in Midland County with eating at Restaurant B or C. A second case-control study, of persons who had eaten at Ector County outlets of Restaurant A, showed an increased risk of acquiring shigellosis with eating foods containing shredded lettuce and tomatoes, which were served together (odds ratio = 68.8; 95% confidence interval 8.5-293.1). All implicated restaurants received shredded lettuce produced at one lettuce-shredding plant; two implicated restaurants did not receive tomatoes from the lot delivered to other implicated restaurants. The lettuce-shredding plant distributed shredded lettuce and intact lettuce; restaurants that received only intact lettuce were not involved in the outbreak. Investigation at the lettuce-shredding plant suggested that a food handler might have been the source of contamination and that the method of processing might have allowed cross-contamination to occur. In the laboratory, the outbreak strain of S. sonnei multiplied rapidly on shredded lettuce at 22 C and survived on refrigerated shredded lettuce for at least seven days. This outbreak, one of the largest outbreaks of Shigella infections in the United States in the last decade, indicates that a large, geographically widespread shigellosis outbreak can result from contaminated shredded lettuce that is distributed commercially.

Adolescent↗