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PubMedDate not supplied

Occurrence of respiratory disease outbreaks in fattening pigs: relation with the features of a densely and a sparsely populated pig area in France.

A survey was carried out in France in 1999 in a Densely Populated Pig Area (DPPA) and a Sparsely Populated Pig Area (SPPA) from which 80 and 55 pig farms were respectively investigated. The two areas were compared regarding the number of respiratory disease outbreaks in fattening pigs on each farm per year with a multiple correspondence analysis and hierarchical clustering. The two areas exhibited different typologies: in the DPPA, high density was associated with a high proportion of finishing-pig units resulting in much moving of piglets within the area. Farrow-to-finish farms located in the DPPA had many contacts with external vehicles; this was associated with more than two respiratory disease outbreaks per farm per year. There also was a lack of biosecurity measures implemented on these farms. Conversely, the good health situation of the farms located in the SPPA was associated with few external contacts and good biosecurity measures. In a second step, risk factors for the occurrence of more than 2 respiratory outbreaks per year were studied. Having more than 4 pig farms within a 2 km radius area, more than 30 incoming rendering trucks per year, and storage of the carcasses of dead animals within the farm yard perimeter increased the risk of occurrence of more than 2 respiratory disease outbreaks per year on the farm. This risk was also increased when there were more than 2 animal-transport lorries entering the farm per month and more than 1 veterinarian's or technician's vehicle coming in every 2 months. These results were discussed because of possible bias due to the retrospective design of the survey and the sampling scheme (randomisation within two areas).

Animals↗

PubMed2003

Surgical site infections after arthroscopy: Outbreak investigation and case control study.

PURPOSE: The goal of this study was to determine the causes of increased post-arthroscopy surgical site infections (SSIs) and to define risk factors for infection. TYPE OF STUDY: Outbreak investigation and case control study at a university-affiliated community hospital from 1994 to 1996, with surveillance through 1999. METHODS: Demographic, clinical, and microbiological data were collected on 27 post-arthroscopy SSIs from 1994 through 1999. Risk factors for SSI were identified by case-control analysis and presented as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Initial investigation revealed an increased annual rate of post-arthroscopy SSIs in 1995 (1.3%). Infection control deficiencies were identified, and feedback was provided to surgeons and staff. Instrument sterilization was standardized, flash sterilization prohibited, and preoperative shaving discouraged. Case-control analysis of 10 cases (from 1994 to 1996) found a statistically significant increase in risk of SSI with intra-articular corticosteroid joint injection (OR, 9.33; 95% CI, 1.6 to 64.9); other risk factors did not reach statistical significance. SSI rates dropped after feedback and education (0.34% in 1996). Continued surveillance revealed 2 smaller outbreaks, in December 1997 (1997 rate, 1.13%) and September 1998 (1998 rate, 1.09%). Case-control analysis of the 17 cases occurring in 1997 through 1999 was also performed. The 1997 outbreak appeared to be related to preoperative razor shaving (P =.003), which was then prohibited by hospital policy. One scrub nurse was also associated with 75% of these cases, which were culture-positive for coagulase-negative Staphylococcus. The cases in the 1998 outbreak shared prolonged procedure duration and conversion to arthrotomy. Of 27 cases, 24 required repeat hospitalization and repeat surgery, at an average excess cost of $9,154.84 per case. All received prolonged courses of intravenous or oral antibiotics. CONCLUSIONS: Post-arthroscopy SSIs are associated with significant morbidity and cost. Although small numbers make finding statistical significance difficult in case-control studies, infection control and CDC-recommended interventions can lower SSI rates. Careful definitions, ongoing surveillance, and long-term follow-up are helpful in reporting results of infection control interventions.

Adrenal Cortex Hormones↗

PubMed1999

An outbreak due to echovirus type 30 in a neonatal unit in France in 1997: usefulness of PCR diagnosis.

Between February and August 1997, 53 patients with enterovirus meningitis were hospitalized in Clermont-Ferrand, France. All but one were children. Echovirus type 30 was involved in 70% of cases with identified serotype. The outbreak ceased on August 8. Two months later, a neonate was admitted to the neonatal unit with an echovirus type 30 meningitis thought to be acquired at delivery. Twenty days later a nosocomial outbreak of echovirus type 30 involving five neonates occurred. Two of them presented with meningitis and two with febrile seizure; One was asymptomatic. The retrospective examination of the maternal sera in a neutralization test, using the index case strain as a source of antigen, showed that none of the neonates was passively immunized before hospitalization. The use of genome detection in cerebrospinal fluid allowed rapid diagnosis and infection was contained by re-inforcing hygiene measures. Prospective examination of stools in the neonatal and paediatric units showed no further occurrences of the disease. No sporadic case was observed in the general population. Hence, nosocomial infections can occur a long time after an outbreak in the general population; rapid diagnosis with molecular tools is useful both for a definite diagnosis in patients already hospitalized, and to act as a rapid alert, even in intervals between seasonal outbreaks.

Adult↗

PubMed2000

Control of a methicillin-resistant Staphylococcus aureus outbreak in a neonatal intensive care unit by unselective use of nasal mupirocin ointment.

In September 1996, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) colonization occurred in the neonatal intensive care unit (NICU) of our hospital. After failing to control the outbreak by conventional methods we implemented an intranasal blanket use programme of mupirocin ointment from the beginning of November 1997. In the programme, patients who had been carrying MRSA received intranasal administration of the ointment three times daily for the first three days and consecutively three times weekly, while newly admitted patients and those who had not been colonized were prophylactically medicated three times weekly. This blanket administration was executed for one month. Methicillin-resistant Staphylococcus aureus colonization became undetectable in all but one intubated inpatient who had already been colonized before the start of the programme, and no new acquisitions occurred until the middle of January 1998, seven weeks after the termination of the blanket use programme. The rate of colonized patients in the unit also decreased. During and after the programme, neither an increase in minimum inhibitory concentration for the antibiotic nor apparent adverse reactions in any of the treated patients were observed. We concluded that this procedure is an effective method of controlling an MRSA outbreak in an NICU when the outbreak cannot be managed with conventional measures.

Administration, Intranasal↗

PubMed2002

Management of an outbreak of Enterobacter cloacae in a neonatal unit using simple preventive measures.

Enterobacter cloacae is becoming an increasingly important nosocomial pathogen. Outbreaks of E. cloacae in intensive care units and burns units have been described frequently. In December 1999, a neonate with line sepsis was transferred from a university hospital to the neonatal unit of the Diakonessen Hospital. Blood culture yielded E. cloacae. An outbreak of E. cloacae was occurring in the university hospital at that time. In February 2000, a second neonate in our hospital developed line sepsis caused by E. cloacae. Direct measures taken included cohorting of infected children, disinfection of incubators, thermometers and wards, and screening patients. Of nine neonates, seven were colonized with E. cloacae. Despite these measures, the outbreak continued. Forty-one patients were screened; 15 were colonized. Environmental searches yielded E. cloacae in a sink and on two thermometers. Sixteen isolates were typed by arbitrarily primed PCR using four primers. All the patient isolates and the two isolates from thermometers were identical. The strain isolated from the sink was unrelated. Amplified fragment length polymorphism typing showed that the outbreak clone was identical to that in the university hospital. After the introduction of disposable thermometer covers, E. cloacae colonization slowly decreased.

Cross Infection↗

PubMed2002

Environmental contamination during a carbapenem-resistant Acinetobacter baumannii outbreak in an intensive care unit.

During a three-month period in 1999, 25 strains of carbapenem resistant Acinetobacter baumannii were isolated from 12 of 170 hospitalized intensive care unit (ICU) patients, of which 16 were considered to be clinically significant. These strains were indistinguishable by biotyping and antibiograms, but genotyping was not performed. Appropriate antibiotic treatment, isolation precautions, and infection control education of the staff failed to halt the outbreak. Environmental contamination was therefore investigated, and A. baumannii was found out in 22 (39.3%) of 56 environmental samples obtained by swabbing. Different antibiotic sensitivity patterns were obtained in the majority of these isolates, but four (7.1%) of the strains were found to have the same sensitivity pattern as the strain causing the outbreak. As a result the ICU was closed, equipment and the environment cleaned, with hypochlorite and terminal disinfection carried out. No bacteria were grown on repeat environmental cultures. Environmental contamination has an important reservoir role in outbreaks of A. baumannii in ICUs and must be eradicated in order to overcome such outbreaks.

Acinetobacter Infections↗

PubMed2002

An outbreak of Serratia marcescens infection in a special-care baby unit of a community hospital in United Arab Emirates: the importance of the air conditioner duct as a nosocomial reservoir.

We report an outbreak of Serratia marcescens infection in a special-care baby unit (SCBU) of a university-affiliated community hospital in the United Arab Emirates. The outbreak involved 36 infants and lasted for 20 weeks. Seven of the colonized infants developed invasive illnesses in the form of bacteraemia (four cases), bacteraemic meningitis (two) and clinical sepsis (one). Three other term infants had purulent conjunctivitis. There were five deaths with an overall mortality of 14%. S. marcescens was cultured from airflow samples from the air conditioning (AC) which was the reservoir of infection in this outbreak. Elimination of the nosocomial source and outbreak containment were eventually achieved by specialized robotic cleaning of the entire AC duct system of the SCBU. Strict adherence to the infection control policies was reinforced to prevent transmission of cross-infection.

Air Conditioning↗

PubMed2005

[Nation-wide outbreak of Salmonella Give in Germany, 2004].

PURPOSE: In spring and summer 2004, a multistate outbreak of infections caused by Salmonella enterica serovar Give (S. Give), a relatively rare serovar in Germany, was detected. In order to identify a common exposure and to describe the characteristics of infections caused by S. Give, an outbreak investigation was performed. MATERIALS AND METHODS: In addition to passive surveillance through mandatory case-reporting, active case-finding was conducted. A case-control study was undertaken in order to identify the probable vehicle of infection. S. Give strains were isolated and molecular subtyping was performed by pulsed-field gel electrophoresis (PFGE). Rates of hospitalization were assessed in patients with S. Give infection, and compared to the rates found in patients infected by the most common serovar in Germany, S. enteritidis. RESULTS: From March to July 2004, 115 cases of gastroenteritis caused by S. Give were identified, with highest incidences being observed in the states of Lower Saxony and Saxony-Anhalt. Consumption of raw minced pork was strongly associated with S. Give infections (OR: 8.0; 95% CI 2.3-27.7; P = 0.001). This result was confirmed by the detection of common outbreak strains in isolates from both patients and pork, using PFGE. Infections caused by S. Give lead to hospitalization in 55% of patients > or = 60 years, but only in 17 % of younger patients (OR: 6.0; 95% CI 2.1-16.3; P < 0.001) and 33% in patients > or = 60 years with infections caused by S. enteritidis (OR: 2.5; 95% CI 1.1-5.4; P = 0.02). CONCLUSION: This is, to our knowledge, the first documented multistate outbreak of salmonellosis associated with the consumption of raw minced pork in Germany. Since contamination of pork meat with Salmonella cannot be avoided, people with risk factors for severe infection should generally avoid the consumption of raw minced pork. The high hospitalization rates in patients > or = 60 years infected with S. Give possibly indicate a higher virulence of this specific serovar. Even in non-typhoidal salmonellosis, early antibiotic therapy should be considered depending on infecting serovar, age and medical history of the patient.

Age Factors↗

PubMed1980

An outbreak of rubella among hospital personnel.

An outbreak of 47 cases of rubella occurred among hospital personnel in a large medical-surgical hospital. As a result, one pregnancy was terminated and 475 employee workdays were lost. Epidemiologic investigation of the outbreak suggested a common source; a dietary worker was identified as the probable index case. Serum samples of 12 per cent of women employees were negative for rubella antibody at the time of the outbreak. Neither a history of rubella nor a history of immunization with rubella vaccine was reliable in the prediction of the presence or absence of immunity. Two thirds of all hospital personnel were immunized through a voluntary mass-immunization program, but the response of physicians to the program was disappointing. Outbreaks of rubella that occur in hospitals with prenatal clinics are of special concern. Testing of all employees for rubella antibody and immunization of those determined to be seronegative should be considered.

Adolescent↗

PubMed1981

Kawasaki syndrome: description of two outbreaks in the United States.

Investigation of two outbreaks of Kawasaki syndrome (KS) in the United States in 1979 and in 1980 revealed no evidence of person-to-person transmission or of a common-source exposure among patients. Questionnaire data showed that KS was more likely to occur in children of middle and upper socioeconomic status than in those of lower status (P less than 0.05 and P less than 0.001 for the respective outbreaks) and that patients with KS had a higher incidence of an antecedent, primarily respiratory illness than did controls matched for age, sex, and race (83% of patients in the first outbreak vs. 30% of one control group, P less than 0.01, and vs. 36% of another control group, P less than 0.02; and 56% of patients in the second outbreak vs. 32% of their controls, P less than 0.02). However, laboratory studies did not identify an etiologic agent for either KS or for the antecedent illness that may be a risk factor for KS.

Adolescent↗

PubMed1987

An outbreak of thyrotoxicosis caused by the consumption of bovine thyroid gland in ground beef.

We report an outbreak of thyrotoxicosis without true hyperthyroidism that occurred between April 1984 and August 1985 among residents of southwestern Minnesota and adjacent areas of South Dakota and Iowa. One hundred twenty-one cases were identified through surveillance of medical clinics, laboratories, hospitals, and physicians' offices. Investigation of the outbreak demonstrated an association between the occurrence of thyrotoxicosis and the consumption of ground beef prepared from neck trimmings processed by a single slaughtering plant (odds ratio, 19.0; P = 0.0001). The cause was confirmed by the findings of bovine thyroid tissue in samples of these trimmings and high concentrations of thyroid hormone in implicated samples of ground beef and the demonstration of prompt increases in serum thyroid hormone concentrations in volunteers who ate the implicated ground beef. Bovine thyroid tissue had been introduced into the neck trimmings inadvertently during the process of "gullet trimming," a procedure that harvests muscles from the bovine larynx. The outbreak resolved after this procedure was discontinued at the plant. The clinical features of the illness suggested the diagnosis of silent thyroiditis, and it is possible that sporadic cases--or even outbreaks--of thyrotoxicosis factitia caused by this mechanism may have occurred in the past but were not recognized.

Adolescent↗

PubMed1988

Molecular epidemiology of the 1984-1986 outbreak of diphtheria in Sweden.

Despite mass vaccination against diphtheria, many people have antibody titers below the protective level of 0.01 IU per milliliter. A recent outbreak of diphtheria in Sweden caused 17 clinical cases of diphtheria in the city of Göteborg; three of the patients died. A satellite outbreak occurred in Stockholm after a few months' delay. Using a new genetic probe, we analyzed 36 strains of Corynebacterium diphtheriae isolated in Sweden and Denmark during the period 1976 to 1986. Although the 36 strains can be classified in 17 different groups of C. diphtheriae (several of them containing toxigenic strains), all the clinical and fatal cases of diphtheria were caused by isolates from the same group, strongly suggesting that the outbreak in Sweden was caused by a single strain that possibly had a virulence factor separate from toxigenicity. This strain may have been imported into Sweden from Denmark, since it was isolated for the first time in Copenhagen in 1983, before the outbreak in Sweden.

Corynebacterium diphtheriae↗

PubMed1989

Community outbreaks of asthma associated with inhalation of soybean dust. Toxicoepidemiological Committee.

Since 1981, 26 outbreaks of asthma have been detected in the city of Barcelona. The geographic clustering of cases close to the harbor led us to consider the harbor as the probable source of the outbreaks. We therefore studied the association between the unloading of 26 products from ships in the harbor and outbreaks of asthma in 1985 and 1986. All 13 asthma-epidemic days in these two years coincided with the unloading of soybeans (lower 95 percent confidence limit of the risk ratio, 7.2). Of the remaining 25 products, only the unloading of wheat was related to the epidemics of asthma, although when adjusted for the unloading of soybeans the relation was not statistically significant. High-pressure areas and mild southeasterly to southwesterly winds, which favored the movement of air from the harbor to the city, were registered on all epidemic days. Particles of starch and episperm cells that were recovered from air samplers placed in the city had morphologic characteristics identical to those of soybean particles. Furthermore, the lack of bag filters at the top of one of the harbor silos into which soybeans were unloaded allowed the release of soybean dust into the air. We conclude that these outbreaks of asthma in Barcelona were caused by the inhalation of soybean dust released during the unloading of soybeans at the city harbor.

Asthma↗

PubMed1996

A national outbreak of Salmonella enteritidis infections from ice cream. The Investigation Team.

BACKGROUND: In September 1994, the Minnesota Department of Health detected an increase in the number of reports of Salmonella enteritidis infections. After a case-control study implicated a nationally distributed brand of ice cream (Schwan's) in the outbreak, the product was recalled and further epidemiologic and microbiologic investigations were conducted. METHODS: We defined an outbreak-associated case of S. enteritidis infection as one in which S. enteritidis was cultured from a person who became ill in September or October 1994. We established national surveillance and surveyed customers of the implicated manufacturer. The steps involved in the manufacture of ice cream associated with cases of S. enteritidis infection were compared with those of products not known to be associated with infection matched for the date of manufacture. Cultures for bacteria were obtained from ice cream samples, the ice cream plant, and tanker trailers that had transported the ice cream base (premix) to the plant. RESULTS: We estimate that S. enteritidis gastroenteritis developed in 224,000 persons in the United States after they ate Schwan's ice cream. The attack rate for consumers was 6.6 percent. Ice cream associated with infection contained a higher percentage of premix that had been transported by tanker that had carried nonpasteurized eggs immediately before (P = 0.02). S. enteritidis was isolated from 8 of 226 ice cream products (3 percent), but not from environmental samples obtained from the ice cream plant (n = 157) or tanker trailers (n = 204). CONCLUSIONS: This nationwide outbreak of salmonellosis was most likely the result of contamination of pasteurized ice cream premix during transport in tanker trailers that had previously carried nonpasteurized liquid eggs containing S. enteritidis. To prevent further outbreaks, food products not destined for repasteurization should be transported in dedicated containers.

Adolescent↗

PubMed1998

An outbreak involving extensive transmission of a virulent strain of Mycobacterium tuberculosis.

BACKGROUND AND METHODS: From 1994 to 1996, there was a large outbreak of tuberculosis in a small, rural community with a population at low risk for tuberculosis. Twenty-one patients with tuberculosis (15 with positive cultures) were identified; the DNA fingerprints of the 13 isolates available for testing were identical. To determine the extent of transmission, we investigated both the close and casual contacts of the patients. Using a mouse model, we also studied the virulence of the strain of Mycobacterium tuberculosis that caused the outbreak. RESULTS: The index patient, in whom tuberculosis was diagnosed in 1995; the source patient, in whom the disease was diagnosed in 1994; and a patient in whom the disease was diagnosed in 1996 infected the other 18 persons. In five, active disease developed after only brief, casual exposure. There was extensive transmission from the three patients to both close and casual contacts. Of the 429 contacts, 311 (72 percent) had positive skin tests, including 81 [corrected] with documented skin-test conversions. Mice infected with the virulent Erdman strain of M. tuberculosis had approximately 1000 bacilli per lung after 10 days and about 10,000 bacilli per lung after 20 days. In contrast, mice infected with the strain involved in the outbreak had about 10,000 bacilli per lung after 10 days and about 10 million bacilli per lung after 20 days. CONCLUSIONS: In this outbreak of tuberculosis, the growth characteristics of the strain involved greatly exceeded those of other clinical isolates of M. tuberculosis. The extensive transmission of tuberculosis may have been due to the increased virulence of the strain rather than to environmental factors or patient characteristics.

Adult↗

PubMed1998

An outbreak of multidrug-resistant pneumococcal pneumonia and bacteremia among unvaccinated nursing home residents.

BACKGROUND: Outbreaks of pneumococcal disease are uncommon and have occurred mainly in institutional settings. Epidemic, invasive, drug-resistant pneumococcal disease has not been seen among adults in the United States. In February 1996, there was an outbreak of multidrug-resistant pneumococcal pneumonia among the residents of a nursing home in rural Oklahoma. METHODS: We obtained nasopharyngeal swabs for culture from residents and employees. Streptococcus pneumoniae isolates were serotyped and compared by pulsed-field gel electrophoresis. A retrospective cohort study was conducted to identify factors associated with colonization and disease. RESULTS: Pneumonia developed in 11 of 84 residents (13 percent), 3 of whom died. Multidrug-resistant S. pneumoniae, serotype 23F, was isolated from blood and sputum from 7 of the 11 residents with pneumonia (64 percent) and from nasopharygeal specimens from 17 of the 74 residents tested (23 percent) and 2 of the 69 employees tested (3 percent). All the serotype 23F isolates were identical according to pulsed-field gel electrophoresis. Recent use of antibiotics was associated with both colonization (relative risk, 2.3; 95 percent confidence interval, 1.3 to 4.2) and disease (relative risk, 3.6; 95 percent confidence interval, 1.2 to 10.8). Only three residents (4 percent) had undergone pneumococcal vaccination. After residents received pneumococcal vaccine and prophylactic antibiotics, there were no additional cases of pneumonia, and the rates of carriage decreased substantially. CONCLUSIONS: In this outbreak a single pneumococcal strain was disseminated among the residents and employees of a nursing home. The high prevalence of colonization with a virulent organism in an unvaccinated population contributed to the high attack rate. Clusters of pneumococcal disease may be underrecognized in nursing homes, and wider use of pneumococcal vaccine is important to prevent institutional outbreaks of drug-resistant S. pneumoniae infection.

Adult↗

PubMed1999

A multistate, foodborne outbreak of hepatitis A. National Hepatitis A Investigation Team.

BACKGROUND: We investigated a large, foodborne outbreak of hepatitis A that occurred in February and March 1997 in Michigan and then extended the investigation to determine whether it was related to sporadic cases reported in other states among persons who had consumed frozen strawberries, the food suspected of causing the outbreak. METHODS: The cases of hepatitis A were serologically confirmed. Epidemiologic studies were conducted in the two states with sufficient numbers of cases, Michigan and Maine. Hepatitis A virus RNA detected in clinical specimens was sequenced to determine the relatedness of the virus from outbreak-related cases and other cases. RESULTS: A total of 213 cases of hepatitis A were reported from 23 schools in Michigan and 29 cases from 13 schools in Maine, with the median rate of attack ranging from 0.2 to 14 percent. Hepatitis A was associated with the consumption of frozen strawberries in a case-control study (odds ratio for the disease, 8.3; 95 percent confidence interval, 2.1 to 33) and a cohort study (relative risk of infection, 7.5; 95 percent confidence interval, 1.1 to 53) in Michigan and in a case-control study in Maine (odds ratio for infection, 3.4; 95 percent confidence interval, 1.0 to 14). The genetic sequences of viruses from 126 patients in Michigan and Maine were identical to one another and to those from 5 patients in Wisconsin and 7 patients in Arizona, all of whom attended schools where frozen strawberries from the same processor had been served, and to those in 2 patients from Louisiana, both of whom had consumed commercially prepared products containing frozen strawberries from the same processor. CONCLUSIONS: We describe a large outbreak of hepatitis A in Michigan that was associated with the consumption of frozen strawberries. We found apparently sporadic cases in other states that could be linked to the same source by viral genetic analysis.

Adolescent↗

PubMed2002

An outbreak of Escherichia coli O157:H7 infections among visitors to a dairy farm.

BACKGROUND: Outbreaks of Escherichia coli O157:H7 infections have involved direct transmission from animals and their environment to humans. We describe an outbreak among visitors to a Pennsylvania dairy and petting farm that provides public access to animals. METHODS: We conducted both a case-control study among visitors to a farm to identify risk factors for infection and a household survey to determine the rates of diarrheal illness among these visitors. We performed an extensive environmental study to identify sources of E. coli O157:H7 on the farm. RESULTS: Fifty-one patients with confirmed or suspected E. coli O157:H7 infection were enrolled in the case-control study. The median age of the patients was four years, and the hemolytic-uremic syndrome developed in eight. Contact with calves and their environment was associated with an increased risk of infection, whereas hand washing was protective. The household survey indicated that visitors to the farm during the outbreak had higher than expected rates of diarrhea. Environmental studies showed that 28 of the 216 cattle on the farm (13 percent) were colonized with E. coli O157:H7 that had the same distinct pattern on pulsed-field gel electrophoresis that was found in isolates from the patients. This organism was also recovered from surfaces that were accessible to the public. CONCLUSIONS: In a large outbreak of E. coli O157:H7 infections among visitors to a dairy farm, predominantly children, high rates of carriage of E. coli O157:H7 among calves and young cattle most likely resulted in contamination of both the animals' hides and the environment.

Adolescent↗