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PubMed1986

Widespread outbreaks of clam- and oyster-associated gastroenteritis. Role of Norwalk virus.

Consumption of raw shellfish has long been known to be associated with individual cases and sporadic outbreaks of enteric illness. However, during 1982, outbreaks of gastroenteritis associated with eating raw shellfish reached epidemic proportions in New York State. Between May 1 and December 31, there were 103 well-documented outbreaks in which 1017 persons became ill: 813 cases were related to eating clams, and 204 to eating oysters. The most common symptoms were diarrhea, nausea, abdominal cramps, and vomiting. Incubation periods were generally 24 to 48 hours long, and the duration of illness was 24 to 48 hours. Bacteriologic analyses of stool and shellfish specimens did not reveal a causative agent. Norwalk virus was implicated as the predominant etiologic agent by clinical features of the illness and by seroconversion and the formation of IgM antibody to Norwalk virus in paired serum samples from persons in five (71 percent) of seven outbreaks in which testing was done. In addition, Norwalk virus was identified by radioimmunoassay in clam and oyster specimens from two of the outbreaks. Determining the source of the shellfish was not always possible, but northeastern coastal waters were implicated. The magnitude, persistence, and widespread nature of these outbreaks raise further questions about the safety of consuming raw shellfish.

Antibodies, Viral↗

PubMed2026

Interspecies Exchange of Mobile Genetic Elements During a Plant Disease Outbreak.

Outbreak sequencing provides insight into the origin and evolutionary processes acting on emerging pathogens. Sequencing a historic multihost outbreak of Ralstonia spp. in Martinique shows the outbreak was caused by two lineages that diverged at separate times from mainland populations. One lineage (Ralstonia pseudosolanacearum I-18) was originally introduced from Asia to South America, where it became well established prior to its dissemination to Martinique, where it retains a signature of specialization on solanaceous hosts. The novel lineage first identified during the outbreak (Ralstonia solanacearum IIB-4NPB) arose from a mainland population endemic to the Americas prior to its arrival in Martinique, where host-range expansion was observed. In contrast to minor changes in secreted effector protein repertoires, the emergent R. solanacearum IIB-4NPB acquired a novel integrative and conjugative element (ICERsoRUN1145). After identifying all Ralstonia spp. ICEs and mapping their spatial and phylogenetic distribution among Ralstonia spp. sampled during the outbreak, we found closely related ICEs circulating in mainland populations of R. pseudosolanacearum, indicating likely exchange between introduced and endemic Ralstonia spp. The family of ICEs in Ralstonia (ICERs) has a conserved bipartite structure and display a striking pattern of functional specialization in each cargo gene insertion hotspot: the first hotspot is a target for metabolic gene acquisition, and the second is a target for defense element acquisition. This work provides unparalleled phylogenetic and spatial resolution of an unusual outbreak and highlights the role of horizontal transfer in shaping the ecological success of an emerging pathogen.

Plant Diseases↗

PubMed1989

Shigellosis outbreaks at summer camps for the mentally retarded in New York State.

During 1987, four New York State summer camps for the mentally retarded and developmentally disabled experienced outbreaks of Shigella sonnei gastroenteritis. Cases occurred in 150 of 286 (attack rate (AR) = 52%), 167 of 295 (AR = 57%), and 25 of 114 (AR = 22%) persons in three camps, respectively; a fourth camp reported eight cases. Epidemiologic investigation suggested point-source foodborne outbreaks in two camps, while person-to-person spread appeared to predominate in the other two. Numerous secondary cases were identified among contacts outside the facilities in the second and third camps. To quantify the extent of the problem, the authors reviewed data on 77 infectious disease outbreaks (12 in camps for the handicapped and 65 in camps for the nonhandicapped) that occurred in the 12,484 registered camp sessions (316 for the handicapped and 12,168 for the nonhandicapped) held during the six-year period 1982-1987. Camps for the handicapped demonstrated approximately a seven times greater risk for all types of infectious disease outbreaks (AR = 38 outbreaks/1,000 camp sessions vs. five outbreaks/1,000 camp sessions; relative risk (RR) = 7.1, 95% confidence interval (CI) 3.9-13.0), including those of gastrointestinal etiology (RR = 8.6, 95% CI 4.4-16.8) and those due to Shigella (RR = infinity). Large camp size (RR = 2.3, 95% CI 1.3-4.1) and long duration of camp sessions (RR = 3.9, 95% CI 1.3-11.6) also increased the risk for outbreaks; however, this risk was predominantly in the camps for the nonhandicapped--other factors relating to personal hygiene and close camper-staff contact were probably more important in the camps for the handicapped. These outbreaks demonstrate the impact of shigellosis at summer camps for the mentally retarded and the need for early preventive action.

Adult↗

PubMed1989

Treatment of an influenza A outbreak in a teaching nursing home. Effectiveness of a protocol for prevention and control.

The safety and efficacy of current ACIP guidelines for the prevention and control of influenza in nursing home populations are uncertain. An outbreak of influenza A/Sichuan (H3N2) in a teaching nursing home during 1988 gave us the opportunity to evaluate the effectiveness of an influenza vaccination and amantadine prophylaxis protocol. Over 13 days, 12 of 60 residents developed influenza. Prior influenza vaccination had been given to 94% of the residents. Protection from infection occurred in those tested who had antibody levels greater than or equal to 1:16 to the A/Leningrad (H3N2) antigen contained in the standard 1987-88 trivalent vaccine. However, five of 17 vaccinated residents who were tested had antibody levels less than or equal to 1:16 at the start of the outbreak. Amantadine (less than or equal to 100 mg/day) was given to all but one resident starting on the third day of the outbreak, and to employees starting on the sixth day of the outbreaks. Seven residents developed illness after the start of amantadine, although amantadine appeared to ameliorate their symptoms. Although amantadine was generally well tolerated by residents, employees receiving amantadine identified a high incidence of side effects and only 44% of employees took at least 70% of the prescribed amantadine. In our opinion, early detection and protocol-directed intervention probably abated a more severe influenza outbreak. Therefore we support existing recommendations that formal nursing home policies be established to ensure that residents and employees receive annual influenza vaccine and that chemoprophylaxis be used when outbreaks of influenza A are suspected.

Aged↗

PubMed1991

Restriction fragment analysis of a Candida tropicalis outbreak of sternal wound infections.

An apparent single-source outbreak of Candida tropicalis sternal wound infections in eight patients was investigated by utilizing DNA restriction fragment analysis (RFA) with HindIII and BstNI. All eight outbreak isolates appeared to be identical and were easily differentiated from control isolates by DNA RFA. Compared with an arbitrarily selected reference outbreak isolate, greater than or equal to 95% of the bands in the restriction digests identified by a computerized image analysis system from each of the outbreak isolates were identical versus 13 to 53% of the bands in any of the nine control isolates. Outbreak strains were significantly more likely to match the reference outbreak isolate than were controls (P less than 0.0001). The RFA was greatly facilitated by the use of computerized image analysis and confirmed the epidemiologic link between a scrub nurse and the infected patients.

Candida↗

PubMed1992

Comparison of ribotyping and restriction enzyme analysis using pulsed-field gel electrophoresis for distinguishing Legionella pneumophila isolates obtained during a nosocomial outbreak.

Because of the ubiquity of Legionella isolates in aquatic habitats, epidemiologic evaluation of Legionella pneumophila strains is important in the investigation and subsequent control of nosocomial outbreaks of legionellosis. In this study, ribotyping and restriction enzyme analysis by pulsed-field gel electrophoresis (PFGE) were used to compare isolates of L. pneumophila obtained from patients and the environment during a nosocomial outbreak with unrelated control strains. Restriction enzyme analysis by PFGE resolved 14 different patterns among the L. pneumophila serogroup 1 and L. pneumophila serogroup 6 isolates involved in the study. Two of the patterns were observed in the three L. pneumophila serogroup 6 isolates from patients with confirmed nosocomial infections and environmental isolates from the potable water supply, which was, therefore, believed to be the source of the patients' infections. Three more patterns that were not present in isolates from patients with legionellosis were seen in isolates from the hospital environment, demonstrating the presence of multiple strains in the hospital environment. In the outbreak, one distinct pattern occurred among the L. pneumophila serogroup 1 isolates from patients with nosocomial infections, suggesting a common source; however, the source could not be determined. By comparison, ribotyping generated five patterns. However, some control strains of both L. pneumophila serogroups 1 and 6 possessed the same ribotypes as were present in the outbreak isolates. Both techniques were used successfully to subtype the isolates obtained during the investigation of the outbreak. Furthermore, restriction enzyme analysis by PFGE was useful for subdividing ribotypes and for distinguishing strains involved in the outbreak from epidemiologically unrelated strains.

Adult↗

PubMed1992

A multistate outbreak of Salmonella javiana and Salmonella oranienburg infections due to consumption of contaminated cheese.

OBJECTIVE: To determine the source of an outbreak of Salmonella javiana and Salmonella oranienburg infections. DESIGN: Laboratory-based statewide surveillance for Salmonella infections and two separate case-control studies. SETTING: Community- and industry-based studies conducted from May through October 1989. PARTICIPANTS: Thirty-one culture-confirmed outbreak-associated cases of S javiana infection and 60 community controls matched for telephone prefix, gender, and age in case-control study I; 50 cases, 100 community controls, and 64 family member controls in case-control study II. RESULTS: One hundred thirty-six culture-confirmed cases of S javiana infection and 11 cases of S oranienburg infection were associated with the outbreak in Minnesota. Outbreak-associated cases were also identified in Wisconsin (15 cases), and in Michigan and New York (one case each). Cases were more likely than controls to have consumed mozzarella cheese manufactured at a single cheese plant (plant X) or cheese that had been shredded at processing plants that also shredded cheese manufactured at plant X (odds ratio [OR], 7.2; 95% confidence interval [CI], 1.7 to 23.2; P < .01). The outbreak-associated strains of both serovars were isolated from two unopened 16-oz (0.45-kg) blocks of mozzarella cheese produced at plant X. The most probable numbers of Salmonella organisms in these samples were 0.36/100 g and 4.3/100 g. CONCLUSIONS: The potential for bacterial pathogen contamination of cheese during manufacture and processing has important epidemiologic implications, particularly because cheese consumption has recently increased in the United States. Low-level contamination of a nationally distributed food product can cause geographically dispersed foodborne outbreaks that may be difficult to detect.

Adolescent↗

PubMed1992

Revaccination of children during school-based measles outbreaks: potential impact of a new policy recommendation.

OBJECTIVE: To evaluate the potential impact of revaccination on measles outbreak control during school-based epidemics. DESIGN: Retrospective cohort study. SETTING: Thirty-two public elementary and high schools in 14 communities on the west island of Montreal. PARTICIPANTS: All 19,439 children attending these schools during the 1989 measles epidemic in Quebec. INTERVENTION: After notification of a case children with provider-verified records of vaccination on or after their first birthday were identified; the remaining children were vaccinated or excluded from school. OUTCOME MEASURE: Clinical or confirmed measles cases not prevented by this intervention that could have been prevented had revaccination been included during the outbreak. RESULTS: Of the 88 measles cases (74 confirmed) proof of one adequate vaccination was present in 48 (55%). Intervention generally occurred within 5 school days after case notification. The nonpreventable cases involved 75 children who had measles onset before the intervention and 11 (7 vaccinated) who had onset within 8 days after the intervention. The two remaining cases occurred 20 and 25 days after the intervention among nonvaccinated students who refused to be vaccinated. Except for these two cases measles was eliminated at every school. Application of the new Canadian guidelines for measles outbreak control would have required the administration of at least 10,000 additional doses during the outbreak to students vaccinated before 1980; implementation of the new US guidelines would have required the administration of 16,629 additional doses to children previously vaccinated only once. Well-enforced provincial regulations ensuring vaccination of every student upon school entry might have prevented 38 (43%) of the cases. The US recommendation of two routine doses of vaccine before school entry might have prevented 86 (98%) of the cases. However, revaccination during the outbreak would not have prevented a single additional case. CONCLUSION: Revaccination of previously vaccinated students during a measles outbreak would have been costly and of little benefit.

Adolescent↗

PubMed1991

[Measures to prevent outbreaks of hospital infections].

On the basis of the analysis of 69 outbreaks of hospital infections registered in the USSR in 1986-1989, as well as additional observations made by the authors, a number of factors which determined the present state of the problems concerning this kind of morbidity in the USSR were established: an insufficient level (in cases of enteric infections) or a low level (in cases of purulent septic infections) of etiological diagnosis; poor efficiency of the epidemiological investigation of outbreaks; defects in the work on the prophylactic detection of potential sources of infection among medical staff, parturient women or mothers taking care of their infants. Some possible solutions on these aspects were proposed. Cases of outbreaks of hospital infections among newborns were used as an example demonstrating that such outbreaks were caused mainly by breaches of antiepidemic and sanitary rules in respective hospitals; thus, in one-third of the cases of outbreaks such breaches were observed in maternity clinics with insufficient material and technical equipment. The prevention of these breaches is considered to be the main road to the solution of the whole problem of the prevention of epidemic outbreaks in hospitals.

Adult↗

PubMed1990

[Conclusions from the outbreak of foot-and-mouth disease in the government district of Hannover in 1987/1988].

Knösel und Tiroke (1989) reported recently experiences derived from the control of FMD outbreaks in 1987/88 in Lower Saxony (FRG). On the basis of the described facts and in connection with the observations of the other outbreaks during the last 20 years in the FRG several conclusions were drawn: (1) The compulsory annual vaccination was not able to prevent these outbreaks. (2) Hence follows that very probable introductions of FMD from foreign countries cannot be prevented, especially since such infections were due to infected swill fed to pigs, and those strains were normally not related to the vaccine strains used. (3) Considering all circumstances of the recent outbreaks, it seems unrealistic to believe the primary infection was not due to the escape of virus from the neighboring vaccine plant. (4) The annual vaccination campaigns since 1970 against FMD were useless because most of the primary outbreaks of FMD since then can be traced to the production or the application of vaccines. (5) The legislative control measures are not sufficient to prevent secondary outbreaks. It was recommended to extend the quarantine areas as well as the radius of ring vaccination and to prolong the period of quarantine. (6) The regulation of tremendous losses of trade is obscure because camouflage of the origin of infections blocks the application of the principle of ultimate responsibility. Facit: Eradication of the disease and strict prevention of its introduction into Europe should be the principal strategy of FMD control for the future instead of imperfect protecting one species of the susceptible animal population.

Animals↗

PubMed1990

Medical students as sources of rubella and measles outbreaks.

Medical students demonstrate a high degree of susceptibility to rubella and measles, and hence are at risk for infection and transmission of these viruses. The purpose of our study was to examine the role medical students play as sources or vectors in rubella and measles outbreaks. We conducted a survey of all US and Canadian public health departments to determine how often students were implicated in outbreaks (response rate, 88.7%). We also performed a literature search to identify any cases not reported to health departments, as well as examined the medical, social, and economic consequences of such outbreaks in the medical setting. Since 1981, 9% of health departments have recorded at least one outbreak of rubella or measles in which medical students were specifically implicated as sources or vectors. Increased morbidity, mortality, and adverse economic consequences resulted from these outbreaks. Our data confirm that medical students are important sources/vectors in rubella and measles outbreaks. We recommend that all medical students be immune to these viruses.

Canada↗

PubMed1989

Several sporadic outbreaks of El Tor cholera in Sunpathong, Chiang Mai, September-October, 1987.

From September through October 1987, a cholera outbreak involving 59 cases of biotype El Tor, serotype Inaba occurred in Sunpathong district, Chiang Mai. No cases died. Twenty-seven cases were males and 32 were females. The age ranged between 4 months and 85 years, with a median of 36 years. The outbreak affected 7 small communities, and showed different vehicles of infection. Six housewives and one girl were infected with cholera in the first localized outbreak. The transmission of infection appeared due to the consumption of packed food contaminated by an infected food handler. In the second localized outbreak, 6 young males acquired cholera after eating uncooked fish harvested from a canal contaminated with cholera organisms. Another outbreak of cholera with 24 culture-confirmed cases occurred among guests at a funeral held in one rural village. The source of infection was traced to uncooked pork contaminated from an infected butcher: Early detection of infected persons, rapid identification of possible vehicles of transmission, and prompt implementation of control measures effectively curtailed the extension of these outbreaks.

Adolescent↗

PubMed1988

Waterborne enteric disease outbreaks in Israel, 1976-1985.

Waterborne enteric disease remains a major public health problem in developing countries, as well as in developed countries, such that the World Health Organization declared 1981-90 the International Water Decade. Israeli experience with waterborne disease outbreaks in the decade 1976-85 is reviewed. Community water systems accounted for 52 outbreaks, with 25 occurring between 1976 and 1980 and 27 between 1981 and 1985. Total cases reported in these outbreaks were 7,681 and 10,880 respectively. In the latter period, reported cases resulting from these outbreaks constituted a very high percentage of the total reported cases of diarrheal disease in the country. The waterborne disease outbreaks were mostly due to secondary contamination of water systems due to human error and poor maintenance. In comparison with the United States, Israel experienced 18.7 times as many community waterborne disease outbreaks per capita. The need for routine preventive chlorination, and filtration on a selective basis, of community drinking water systems is strongly indicated, as recommended in current United States and World Health Organization guidelines in order to improve this grossly substandard aspect of Israeli public health.

Bacterial Infections↗

PubMed1978

Epidemiology of common-source outbreaks of shigellosis in the United States, 1961-1975.

In 1961-1975, there were 72 foodborne and 38 waterborne outbreaks of shigellosis reported in the United States. Foodborne outbreaks were most often caused by salads with contamination attributed to poor hygiene of a food handler. Waterborne outbreaks most often involved semipublic water systems, and were usually the result of inadequate chlorination of water contaminated by human feces. In 110 common-source outbreaks, 16,541 persons were ill. The attack rate for both food- and waterborne shigellosis was 47%, and the case-fatality ratio was 0.1% in foodborne outbreaks and 0.2% in waterborne outbreaks.

Disease Outbreaks↗

PubMed1988

Outbreak of staphylococcal scalded skin syndrome among neonates.

Over a period of 2 months, 12 babies born in the maternity unit at Guy's Hospital developed staphylococcal scalded skin syndrome in two distinct outbreaks. Staphylococci isolated from the babies, together with those from the mothers and attending medical staff were phage-typed. All isolates from the babies were of type 3A/3C. During the first outbreak only one carrier of the epidemic strain (a paediatrician) was found but a further 12 persons were identified as possible carriers during the second outbreak. In order to confirm the link between outbreaks, all phage group II isolates were subjected to reverse phage-typing, testing for metal-ion resistance, plasmid profiling and in-vivo testing for production of epidermolytic toxin. It was shown that the same epidemic strain of toxin-producing Staphylococcus aureus was responsible for both outbreaks. The affected neonates responded rapidly to a short course of intravenous flucloxacillin. The outbreak ceased after appropriate treatment of all carriers and the implementation of an extensive disinfection policy within the maternity unit.

Carrier State↗

PubMed1979

[Dimorphous Hansen's disease with outbreaks of Hansen reactions and visceral lesions].

The paper presents the case of a patient with borderline hanseniasis. After a long period of illness, he presented an outbreak with new lesions, that showed reactional tuberculoid aspects; he later presented lesions with clinical and histological aspects of Virchowian hanseniasis. This evolutional type is compatible with the pseudo-exacerbations outbreaks reported by Souza Lima. This patient also presented an Erythema Nodosum outbreak with cutaneous and visceral lesions, the latter occurring with great intensity in the liver parenchyma with clinical manifestations of icterus and hepatomegaly. The pathogenesis of the pseudo-exacerbations outbreaks is discussed, also the special situation of Borderline patients, subject to neurologic injuries during the pseudo-exacerbations outbreaks, and cutaneous, neurological and visceral lesions during the Erythema Nodosum Hansenicum outbreaks.

Erythema Nodosum↗

PubMed1990

Nosocomial outbreak of neonatal gastroenteritis caused by a new serotype 4, subtype 4B human rotavirus.

A nosocomial outbreak of rotavirus gastroenteritis involving 52 newborns occurred between June and September 1988 at the University Children's Hospital of Freiburg, Federal Republic of Germany. Stools from 27 representative patients were examined for rotavirus serotypes, using a monoclonal antibody-based enzyme-linked immunosorbent assay. The electropherotype was also examined by polyacrylamide gel electrophoresis of genomic RNA. As many as 18 patients were found to be infected by serotype 4, subtype 4B strain, and in all of them the same electropherotype was detected. Although rotavirus from the remaining nine patients could not be typed, the electropherotype in four was identical to that of the serotype 4, subtype 4B strain. Thus, most of the patients in the outbreak were infected by the same rotavirus strain. Retrospective epidemiological studies showed that the 4B strain began to circulate at the hospital in January 1988, whereas only rotavirus serotypes 1, 3, and 4A were detected in 1985-1987. The primary case of the outbreak was presumably a newborn with acute gastroenteritis, admitted to the hospital from a small maternity unit in the same urban area. During the outbreak, 12 of 44 healthy newborns in the nurseries of the Children's Hospital and other maternity hospitals were found to be asymptomatic rotavirus carriers, and in three of the newborns the same 4B strain was detected. This is the first reported outbreak caused by a serotype 4, subtype 4B strain.

Cross Infection↗

PubMed1987

A hospital outbreak caused by a chlorhexidine and antibiotic-resistant Proteus mirabilis.

An outbreak of urinary-tract infection involving a strain of Proteus mirabilis resistant to gentamicin and several other antibiotics affected 90 patients in Southampton between July 1980 and May 1985. The outbreak strain was also resistant to chlorhexidine and this, in combination with the antibiogram and Dienes' test, permitted differentiation from other P. mirabilis strains. The outbreak had features in common with other Enterobacteriaceae outbreaks, although certain aspects of the population involved have made it particularly difficult to control. The outbreak commenced shortly after the introduction of a catheter care policy which involved the use of chlorhexidine, and although the majority of the cases were colonized before this policy was enforced, chlorhexidine had been used extensively for other procedures within the district. Preliminary evidence suggests that there is no genetic linkage between the chlorhexidine and multiple antibiotic resistance.

Age Factors↗