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PubMed2005

Mycobacterium tuberculosis transmission among high school students in Greece.

BACKGROUND: The aim of this study was to investigate the requirements and practical steps for screening of Mycobacterium tuberculosis (MTB) transmission among high school student populations in two regional high schools of central Greece. Case-matched control populations from other regional schools were included. METHODS: Case study of two indexed cases, 61 close contacts, 212 casual contacts and 369 controls were investigated. Detailed questionnaires, tuberculin-skin test (PPD test), chest radiography, medical evaluation and DNA fingerprinting of sputum isolates were used. RESULTS: In case A, three (1.97%) of 152 close and casual contacts developed tuberculosis, and a further 25 (16.4%) were classified as infected. In contrast, none of the 121 close or casual contacts investigated for Case B developed tuberculosis or were classified as infected. None of the control populations contained infected individuals. Contacts of case A had a much higher risk (3.08 < RR = 22.29 < 161.69, P < 0.001) of being infected than contacts of case B. Two different strains of MTB were found responsible for these outbreaks. CONCLUSION: There was a considerable difference in the infectivity of the two cases presumably due to environmental and clinical factors, although two different MTB strains were responsible. It is proposed that the extent of case investigation should be individualized with particular emphasis placed among close contacts.

Adolescent↗
PubMed2002

The evolution of bovine viral diarrhea: a review.

The economic importance of bovine viral diarrhea is increasing with the emergence of seemingly more virulent viruses, as evidenced by outbreaks of hemorrhagic syndrome and severe acute bovine viral diarrhea beginning in the 1980s and 1990s. It appears that evolutionary changes in bovine viral diarrhea virus were responsible for these outbreaks. The genetic properties of the classical bovine viral diarrhea virus that contribute to the basis of current diagnostic tests, vaccines, and our understanding of pathogenic mechanisms are now being reevaluated because of these "new" virus strains. This shift in virulence has confounded both nomenclature and the significance of current bovine viral diarrhea virus categorization. The purpose of this review is to summarize our current understanding of bovine viral diarrhea virus with a chronological review of prevailing scientific tenets and practices as described in clinical and scientific North American veterinary journals and textbooks. The first part of this review describes how we have arrived at our current understanding of the viruses, the diseases, and their nomenclature. The second part of the review deals with current concepts in virology and how these concepts may both explain and predict bovine viral diarrhea virus pathogenesis. By reviewing how knowledge of bovine viral diarrhea has evolved and the theories of how the virus itself is able to evolve, the interpretation of diagnostic tests are more effectively utilized in the control and treatment of bovine viral diarrhea virus associated disease.

Animals↗
PubMedDate not supplied

Standardized emergency management system and response to a smallpox emergency.

The smallpox virus is a high-priority, Category-A agent that poses a global, terrorism security risk because it: (1) easily can be disseminated and transmitted from person to person; (2) results in high mortality rates and has the potential for a major public health impact; (3) might cause public panic and social disruption; and (4) requires special action for public health preparedness. In recognition of this risk, the Los Angeles County Department of Health Services (LAC-DHS) developed the Smallpox Preparedness, Response, and Recovery Plan for LAC to prepare for the possibility of an outbreak of smallpox. A unique feature of the LAC-DHS plan is its explicit use of the Standardized Emergency Management System (SEMS) framework for detailing the functions needed to respond to a smallpox emergency. The SEMS includes the Incident Command System (ICS) structure (management, operations, planning/intelligence, logistics, and finance/administration), the mutual-aid system, and the multi/interagency coordination required during a smallpox emergency. Management for incident command includes setting objectives and priorities, information (risk communications), safety, and liaison. Operations includes control and containment of a smallpox outbreak including ring vaccination, mass vaccination, adverse events monitoring and assessment, management of confirmed and suspected smallpox cases, contact tracing, active surveillance teams and enhanced hospital-based surveillance, and decontamination. Planning/intelligence functions include developing the incident action plan, epidemiological investigation and analysis of smallpox cases, and epidemiological assessment of the vaccination coverage status of populations at risk. Logistics functions include receiving, handling, inventorying, and distributing smallpox vaccine and vaccination clinic supplies; personnel; transportation; communications; and health care of personnel. Finally, finance/administration functions include monitoring costs related to the smallpox emergency, procurement, and administrative aspects that are not handled by other functional divisions of incident command systems. The plan was developed and is under frequent review by the LAC-DHS Smallpox Planning Working Group, and is reviewed periodically by the LAC Bioterrorism Advisory Committee, and draws upon the Smallpox Response Plan and Guidelines of the Centers for Disease Control and Prevention (CDC) and recommendations of the Advisory Committee on Immunization Practices (ACIP). The Smallpox Preparedness, Response, and Recovery Plan, with its SEMS framework and ICS structure, now is serving as a model for the development of LAC-DHS plans for responses to other terrorist or natural-outbreak responses.

Bioterrorism↗
PubMed2000

Distinct epidemiological patterns of Norwalk-like virus infection.

Norwalk-like viruses (NLV) are important economically as a cause of both sporadic gastroenteritis in the community and large outbreaks in hospitals and other institutional settings. Despite the description of several antigenic types relatively little is known about the epidemiology of these individual types. NLVs were detected by electron microscopy in faecal specimens from 706 outbreaks of gastroenteritis that represented 68% of all outbreaks of non-bacterial gastroenteritis. These outbreaks took place in the counties of West and North Yorkshire and Humberside during six winter seasons between July 1992 and June 1998. NLV strains from 671 outbreaks were typed by antigen capture enzyme linked immunosorbent assays (ELISA) based on antisera made to recombinant virus-like particles of three antigenically distinct NLVs; Norwalk (NV), Mexico (MXV) and Grimsby (GRV) viruses. GRV was the predominant strain for five of the six winter seasons and overall was associated with 61% of NLV outbreaks. MXV was responsible for a single epidemic peak in the winter of 1993/94 but was also observed at other times throughout the study period. NV was only associated with two outbreaks in 1994 that were epidemiologically linked. Strains from the remaining 32% of outbreaks were non-reactive in all three ELISA. Thus, a single NLV antigenic type seems to have predominated during the period 1992 to 1998 in the UK.

Adult↗
PubMed1989

Food-borne disease in hospitals: prevention in a changing food service environment.

The results of an investigation into an outbreak of food-borne disease at a hospital in Los Angeles County are reported. The outbreak occurred at a luncheon buffet for nonpatient visitors attending an event at the hospital, which was catered by the hospital. The food source and etiologic agent(s) responsible for the outbreak were not identified by our investigation. However, several issues relating to the changing character of hospital food provision and their implications for prevention of food-borne disease in hospitals were conspicuous. Two trends apparent in hospital food service are toward increased use of foodstuffs prepared by wholesale food manufacturers and more frequent invitation to community groups to meet within hospital facilities and use hospital catering services. We found that (1) hospital kitchens in Los Angeles County are undersurveyed with respect to frequency of sanitary inspections; (2) hospitals have no mechanism whereby to assess the sanitary inspection record of wholesale food manufacturers from whom they purchase foodstuffs; and (3) crossover of food items prepared for nonpatient hospital visitors, including catered foods, to the inpatient menu occurs. The potential risks for a food-borne disease outbreak among compromised inpatients resulting from these factors are discussed, and measures to reduce such risk are proposed.

Community-Institutional Relations↗
PubMed2005

The experience of SARS-related stigma at Amoy Gardens.

Severe Acute Respiratory Syndrome (SARS) possesses characteristics that render it particularly prone to stigmatization. SARS-related stigma, despite its salience for public health and stigma research, has had little examination. This study combines survey and case study methods to examine subjective stigma among residents of Amoy Gardens (AG), the first officially recognized site of community outbreak of SARS in Hong Kong. A total of 903 residents of AG completed a self-report questionnaire derived from two focus groups conducted toward the end of the 3-month outbreak. Case studies of two residents who lived in Block E, the heart of the SARS epidemic at AG, complement the survey data. Findings show that stigma affected most residents and took various forms of being shunned, insulted, marginalized, and rejected in the domains of work, interpersonal relationships, use of services and schooling. Stigma was also associated with psychosomatic distress. Residents' strategies for diminishing stigma varied with gender, age, education, occupation, and proximity to perceived risk factors for SARS such as residential location, previous SARS infection and the presence of ex-SARS household members. Residents attributed stigma to government mismanagement, contagiousness of the mysterious SARS virus, and alarmist media reporting. Stigma clearly decreased, but never completely disappeared, after the outbreak. The findings confirm and add to existing knowledge on the varied origins, correlates, and impacts of stigma. They also highlight the synergistic roles of inconsistent health policy responses and risk miscommunication by the media in rapidly amplifying stigma toward an unfamiliar illness. While recognizing the intrinsically stigmatizing nature of public health measures to control SARS, we recommend that a consistent inter-sectoral approach is needed to minimize stigma and to make an effective health response to future outbreaks.

Adaptation, Psychological↗
PubMed1993

[Clinical epidemiology of an outbreak of nosocomial infection caused by Staphylococcus aureus resistant to methicillin and aminoglycosides: efficacy of control measures. Comité de Control de Infecciones].

BACKGROUND: The appearance of outbreaks of nosocomial infections due to methicillin resistant Staphylococcus aureus (MRSA) is a current problem in Spain. The clinical and molecular epidemiology of these outbreaks as well as the efficacy of their control measures are a matter of controversy. METHODS: An outbreak of MRSA nosocomial infections in the Hospital Clínic i Provincial of Barcelona, a 953-bed University Hospital, with a total of 347 cases from September 1989 to October 1991 is described. The control measures used include prospective and continued surveillance of all MRSA isolations, identification of the reservoir, use of different types of isolation and control of nasal carriers among health care workers. The MRSA strains isolated were studied by standard microbiological procedures, phage-typing and extrachromosomal (plasmid) DNA analysis by means of restriction endonuclease analysis (REAP). RESULTS: From the Intensive Care Units, the outbreak extended to the medical and surgical wards. Seventy-one percent of the cases corresponded to infected patients and 29% to asymptomatic carrier patients. The MRSA strain responsible of the outbreak had a notable antibiotic multiple-resistance pattern. The studies performed showed that most of the strains belonged to phage group III and were lysed by phage 77. Plasmid DNA analysis showed that 95% of the strains isolated had a unique homogeneous profile. Despite the different control measures used, the MRSA infection has acquired a medium level endemic rate in the Hospital Clínic i Provincial. CONCLUSIONS: The introduction and spread of methicillin-resistant MRSA in a teaching hospital with more than 500-bed may be rapid and affecting large number of patients. Effective control measures carries multiple problems, which must be addressed with the collaboration of all hospital employees. The molecular typing techniques used (REAP) further identified that the outbreak is due to one single MRSA strain, with an epidemiologic behavior identical to the one showed by the epidemic strains previously described in the United Kingdom and Australia.

Aminoglycosides↗
PubMed1975

Immunity to Streptococcus equi.

Using the long chain test, and in some cases the bactericidal test, to measure antibody, the development of the immune response in horses to Str. equi has been followed. Long chain indices in excess of 5.0, accompanied by strong bactericidal capacity, were recorded in serums after the full 3-dose immunisation course with a commercial vaccine. The full course elicited the most satisfactory antibody titres declined within the 12 month post-vaccination period, thus providing support for the recommendation that yearly booster doses should be administered. The immune response in horses during 2 strangles outbreaks was compared with the response following vaccination. Recovered animals showed declining antibody levels 9 weeks after infection, and the evidence does not support longevity of the immune response after natural infection. Reaction to vaccination was observed in those animals with high initial antibody titre.

Animals↗
PubMed2006

A comparison of Listeria monocytogenes serovar 4b isolates of clinical and food origin in Austria by automated ribotyping and pulsed-field gel electrophoresis.

In this study, two typing methods, automated ribotyping and pulsed-field gel electrophoresis (PFGE), were evaluated for the subtyping of Listeria monocytogenes serotype 4b. The strains originated from patients and food samples collected in Austria during 2001-2005 and from Europe and North America in the World Health Organization collaborative study on the subtyping of this species. The largest group of Austrian clinical isolates was of the same PFGE subtype as those isolated from foodborne outbreaks in Switzerland and in the United States. Another subtype of clinical isolates from Austria was indistinguishable to that obtained from isolates responsible for a foodborne outbreak in the United States in 1985. Although the discriminatory power of PFGE was higher than that of automated ribotyping, some PFGE types were differentiated by ribotyping. Thus, combining data obtained by both automated ribotyping and PFGE increases the strain discrimination. Still, many of the Austrian strains remain indistinguishable from strains of foodborne outbreaks in other countries although there is no known epidemiological relation. This complies to previous studies which show the highly clonal nature of L. monocytogenes 4b strains which are responsible for both large outbreaks and sporadic cases.

Animals↗
PubMed2003

Concurrent outbreaks of Shigella sonnei and enterotoxigenic Escherichia coli infections associated with parsley: implications for surveillance and control of foodborne illness.

In recent years, the globalization of the food supply and the development of extensive food distribution networks have increased the risk of foodborne disease outbreaks involving multiple states or countries. In particular, outbreaks associated with fresh produce have emerged as an important public health concern. During July and August 1998, eight restaurant-associated outbreaks of shigellosis caused by a common strain of Shigella sonnei occurred in the United States and Canada. The outbreak strain was characterized by unique pulsed-field gel electrophoresis patterns. Epidemiologic investigation determined that the illness was associated with the ingestion of parsley at four restaurants; at the other four restaurants, the majority of the people who contracted the illness ate parsley. Isolates from patrons in two unrelated restaurant-associated enterotoxigenic Escherichia coli (ETEC) outbreaks in Minnesota shared a common serotype and pulsed-field gel electrophoresis (PFGE) pattern. Parsley was the implicated or suspected source of both ETEC outbreaks. In each of the outbreak-associated restaurants, parsley was chopped, held at room temperature, and used as an ingredient or garnish for multiple dishes. Infected food workers at several restaurants may also have contributed to the propagation of the outbreak. The sources of parsley served in outbreak-associated restaurants were traced, and a 1,600-acre farm in Baja California, Mexico, was identified as a likely source of the parsley implicated in six of the seven Shigella outbreaks and as a possible source of the parsley implicated in the two ETEC outbreaks. Global food supplies and large distribution networks demand strengthened laboratory and epidemiologic capacity to enable state and local public health agencies to conduct foodborne disease surveillance and to promote effective responses to multistate outbreaks.

Canada↗
PubMed1995

Outbreak of leptospirosis with pulmonary involvement in north Andaman.

An outbreak of acute febrile illness with haemorrhagic manifestations and pulmonary involvement occurred in Diglipur of North Andaman during October-November 1993. Investigations were carried out to see whether leptospires were responsible for this outbreak. Serum samples were collected from suspected cases and tested for presence of antibodies to leptospires by microscopic agglutination test (MAT) using a battery of 19 antigens representing 16 serogroups. 66.7 per cent of the specimens showed significant titres of antibodies against leptospires, 18 of 23 paired sera (78.3%) showed sero-conversion or four-fold rise in antibody titres. The commonest serovar involved was Leptospira grippotyphosa followed by L. canicola and L. JEZ bratislava. In 7 patients L. grippotyphosa was the sole serovar against which antibodies were detected. Clinical and epidemiological observations of this outbreak were similar with that of earlier seasonal outbreaks of acute febrile illness with haemorrhagic manifestations occurring in the same area, indicating that the past outbreaks may also have been due to leptospires. This is the first report of pulmonary leptospirosis from India.

Disease Outbreaks↗
PubMed1996

Hepatitis C virus in a hemodialysis unit: molecular evidence for nosocomial transmission.

Between February 1991 and January 1992, elevated alanine aminotransferase (ALT) levels were observed in several hemodialysis patients in a dialysis center in Dendermonde, Belgium. By the end of 1992, 25 out of 68 patients had seroconverted for HCV antibodies. The HCV strains from 23 of these seroconverters were genotyped and classified as genotype 1b. Sequence analysis of the HCV Core region was carried out in 12 patients, 9 of whom were infected with a strain bearing a unique sequence motif as compared with the currently known HCV 1b strains. A new 5' UR/Core line probe assay was designed to screen for such variations. Twenty patients tested positively for this special sequence motif, while the other 3 showed the regular subtype 1b sequence. Phylogenetic analysis of the Core sequences further revealed that the latter three were neither related to the main special strain of the infection, nor to each other. These three strains could be traced to two patients already infected at the time of residence in other dialysis units and to one patient who already showed ALT elevations in 1989. Epidemiological studies revealed no traceable source for this outbreak. In conclusion, molecular analysis demonstrates nosocomial transmissions by a peculiar genotype 1b strain in a dialysis center. Three other genotype 1b strains were also present in the unit, but were not responsible for the outbreak.

Alanine Transaminase↗
PubMed1997

The role of seafood in foodborne diseases in the United States of America.

In the United States of America, seafood ranked third on the list of products which caused foodborne disease between 1983 and 1992. Outbreaks connected with fish vectors were caused by scombroid, ciguatoxin, bacteria and unknown agents; in shellfish, unknown agents, paralytic shellfish poisoning, Vibrio spp. and other bacteria, followed by hepatitis A virus, were responsible for the outbreaks. At least ten genera of bacterial pathogens have been implicated in seafood-borne diseases. Over the past twenty-five years, bacterial pathogens associated with faecal contamination have represented only 4% of the shellfish-associated outbreaks, while naturally-occurring bacteria accounted for 20% of shellfish-related illnesses and 99% of the deaths. Most of these indigenous bacteria fall into the family Vibrionaceae which includes the genera Vibrio, Aeromonas and Plesiomonas. In general, Vibrio spp. are not associated with faecal contamination and therefore faecal indicators do not correlate with the presence of Vibrio. Viruses are the most significant cause of shellfish-associated disease: in New York State, for example, 33% and 62% of 196 outbreaks between 1981 and 1992 were caused by Norwalk virus and gastrointestinal viruses (small round structured viruses), respectively. In addition, several illnesses are a result of toxic algal blooms, the growth of naturally occurring bacteria and diatoms causing neurotoxic shellfish poisoning, paralytic shellfish poisoning, diarrhoetic shellfish poisoning, amnesic shellfish poisoning and ciguatera. Current estimates place the annual number of ciguatera cases at 20,000 world-wide. Scombroid poisoning is the most significant cause of illness associated with seafood. Scombrotoxin is of bacterial origin and halophilic Vibrio spp. causing high histamine levels are implicated as the source. Scombroid poisoning is geographically diverse and many species have been implicated, namely: tuna, mahi-mahi, bluefish, sardines, mackerel, amberjack and abalone. Temperature abuse has been cited as a major cause of scombroid poisoning. For routine work, the use of faecal indicators to predict the relative level of faecal contamination should not be disposed of. However, the main source of seafood illness is due to species which are not predicted by these organisms. In order to protect public health, routine surveillance using new pathogen-specific techniques such as polymerase chain reaction should be used. This, in combination with risk assessment methods and hazard analysis and critical control points, will begin to address the need for improvement in the safety of seafood.

Animals↗
PubMedDate not supplied

First documented outbreak of hepatitis E virus transmission in Java, Indonesia.

A suspected hepatitis outbreak occurred in Bondowoso District, East Java Province, Indonesia, in March-May 1998. An investigation was initiated in April 1998, involving a retrospective review of hospital records, a community-based cross-sectional study, and a health service-based case detection and household follow-up. Sera and epidemiological information were collected from 962 individuals: 235 from 3 outbreak-affected communities along the same rural stretch of river, 101 from community controls living distant from the river, 151 cases detected in health centres, 141 family members of the cases, and 334 subjects from neighbouring families. The prevalence of acute hepatitis E virus (HEV), based on anti-HEV IgM, total antibody (Ig) to HEV and polymerase chain reaction (PCR), was significantly (P < 0.00001) higher (52.4%) among the outbreak communities than among the community controls (3%). The background prevalence of HEV, based on anti-HEV IgG, was also significantly (P < 0.00001) higher (47%) among the outbreak communities than among the community controls (3%). None of the 476 sera screened for anti-HAV (hepatitis A virus) IgM was positive. These results indicate that HEV was the aetiological agent responsible for the outbreak. The overall attack rate (AR) for the 3 outbreak-affected communities surveyed was 19%, with AR determined on the basis of clinically recognized, acute jaundice illness. The usage of river water as primary source for bathing, human-waste disposal, and drinking purposes differed significantly (P < 0.00001) between the communities in outbreak areas and those in non-outbreak areas. There is no significant influence attributed to 'boiling water' on acute HEV. No climatic influences (flooding or drought) predisposed this instance of epidemic HEV transmission. This outbreak represents the first documented evidence of epidemic HEV transmission in Java, Indonesia.

Adolescent↗
PubMed2002

Association of Escherichia coli O157:H7 with preharvest leaf lettuce upon exposure to contaminated irrigation water.

Recent foodborne outbreaks have linked infection by enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 to the consumption of contaminated lettuce. Contamination via food handler error and on-the-farm contamination are thought to be responsible for several outbreaks. Though recent studies have examined the application of EHEC to store-bought lettuce, little is known about the attachment of EHEC to growing plants. We investigated the association of lettuce seedlings with EHEC O157:H7 strains implicated in lettuce or fruit outbreaks using hydroponic and soil model systems. EHEC strains that express the green fluorescent protein were observed by stereomicroscopy and confocal laser scanning microscopy to determine adherence patterns on growing lettuce seedlings. Bacteria adhered preferentially to plant roots in both model systems and to seed coats in the hydroponic system. Two of five nonpathogenic E. coli strains showed decreased adherence to seedling roots in the hydroponic system. EHEC was associated with plants in as few as 3 days in soil, and contamination levels were dose-dependent. EHEC levels associated with young plants inoculated with a low dose suggested that the bacteria had multiplied. These data suggest that preharvest crop contamination via contaminated irrigation water can occur through plant roots.

Bacterial Adhesion↗
PubMed1997

[Typhoid fever in Chile 1977-1990: an emergent disease].

The emergence of old and new communicable diseases is becoming an important public health problem in industrialized and developing countries worldwide. Chile experienced, at the end of the seventies and during the eighties, epidemics of several emergent communicable infectious diseases whose relevance as public health problems had steadily decreased in the previous 25 years. The most striking of these epidemics was a severe outbreak of typhoid fever that lasted at least 10 years. The majority of the cases occurred in the urban setting of Santiago. Several investigators suggested, in light of apparently good sanitation statistics, that factors responsible for this outbreak of typhoid were an increase in the number of chronic carriers of Salmonella typhi, the lack of microbiological food controls and the consumption of vegetables irrigated with waste water contaminated with S typhi. However, there is a dearth of epidemiological information and field work confirming the role of these factors in this typhoid outbreak. Moreover, the sudden, massive and urban characteristics of this epidemic, coupled to contemporary information regarding shortcomings on the preparation of drinking water and on decreased availability of drinking water to the population in Santiago regardless of good sanitation statistics, suggest that this outbreak may have been partially waterborne. The beginning of this typhoid outbreak also coincided with increased rain fall, with rapidly deteriorating economic and social conditions manifested in high rates of unemployment, and with decreased government investment on social services, including sanitation and health. All these factors are known to influence the epidemiology of typhoid and other emergent diseases worldwide.

Chile↗
PubMed2002

Suboptimal measles-mumps-rubella vaccination coverage facilitates an imported measles outbreak in ireland.

The year 2000 saw a dramatic increase in the incidence of measles infections in Ireland, with >1500 cases documented. Initial cases were reported from an area of Dublin with low vaccine uptake and a large immigrant population. Molecular epidemiologic findings revealed that the strain of measles virus responsible for this outbreak was the genotype D2 strain, which is closely related to strains initially identified in South Africa. It is suggested that suboptimal vaccine uptake facilitated the spread of imported measles infection.

Diagnostic Errors↗