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PubMed1997

Capsid sequence diversity in small round structured viruses from recent UK outbreaks of gastroenteritis.

Genetic typing of small round structured viruses (SRSVs) by reverse transcription-polymerase chain reaction (RT-PCR) and sequencing has been confined to analysis of the RNA polymerase because of the considerable genome variability outside of this region. To provide capsid sequence data for epidemiological studies and outbreak investigations, a broadly reactive capsid PCR was developed using two sets of degenerate, inosine-containing primers. Primer pairs Capla/Caplb and Caplla/Capllb specifically amplify a 223-bp region of the SRSV capsid open reading frame from SRSV genetic groups I and II, respectively. The capsid PCR was used to investigate SRSVs from nine UK outbreaks of gastroenteritis occurring between 1992 and 1995. Differential amplification by the primer pairs suggested that three strains belonged to genetic group I and six to genetic group II. The capsid amino acid sequences of the group I strains were 75.9% to 79.3% identical with Sot/91/UK (group I), while those of the group II strains were 75.9% to 98.3% identical with Bri/93/UK (group II). Phylogenetic comparison of the capsid region from the outbreak strains and 13 previously characterised SRSVs revealed clusters of strains closely related to Bri/93/UK and Tor/77/C within genetic group II. With the exception of some Bri/93/UK-like strains, there was no correlation between capsid sequence and the geographical origin of SRSVs. UK strains were found with greater than 90% capsid sequence identity to SRSVs from various locations worldwide including Australia (Cam/94/A), Canada (Tor/77/C), Hawaii (Haw/71/US), and Saudi Arabia (DSV395/90/SA) together with group I (B447/92/UK) and group II (Yat/94/UK) strains that were genetically distinct from known SRSV capsids. Three SRSVs very closely related to Bri/93/UK were from recent UK hospital outbreaks. These Bri/93/UK-like strains appear to be prevalent in the UK.

Amino Acid Sequence↗

PubMed1997

Outbreaks of pseudo-infection with Cyclospora and Cryptosporidium--Florida and New York City, 1995.

Efforts to expand the scope of surveillance and diagnostic testing for emerging infectious diseases also may increase the potential for identifying pseudo-outbreaks (i.e., increases in incidence that may result from enhanced surveillance) and outbreaks of pseudo-infection (i.e., clusters of false-positives for infection). This report describes the investigations of outbreaks of pseudo-infection with Cyclospora in Florida and Cryptosporidium in New York City in 1995 after health departments in those jurisdictions had initiated surveillance for these emerging organisms. These investigations emphasize 1) the need for laboratory training in the identification of emerging pathogens and 2) the importance of confirmation by reference laboratories as an early step in the investigation of any apparent outbreak caused by an emerging pathogen.

Animals↗

PubMed1997

Outbreak of small round structured virus gastroenteritis arose after kitchen assistant vomited.

A wedding reception at a North Yorkshire hotel was followed by an explosive outbreak of gastroenteritis. The attack rate among the 111 guests was 50% and vomiting was a predominant feature. The results of laboratory and epidemiological investigations were consistent with a common source outbreak of small round structured virus (SRSV) infection genotype II. The source of the outbreak was traced to a kitchen assistant who suddenly became ill on the eve of the reception and vomited into a sink used for preparing vegetables. The sink was cleaned with a chlorine based disinfectant and used the next morning to prepare a potato salad, subsequently identified as the vehicle of infection in a cohort study of guests (odds ratio 3.21; CI 1.78-5.78, p = 0.0001). No other food was associated with illness. The outbreak provides further supporting evidence of the importance of vomiting in the transmission of SRSV infection, highlights the virulence of this group of viruses, and indicates their relative resistance to environmental disinfection and decontamination. It also highlights the need for the adequate training of catering staff and the implementation and enforcement of food hygiene regulations.

Caliciviridae Infections↗

PubMed1997

An institutional outbreak of Salmonella enteritidis in Singapore.

A large outbreak of food poisoning occurred in Singapore in March 1995 when a total of 188 inmates in an institution was taken ill. Salmonella enteritidis was isolated from the stool cultures of 35 inmates (16 symptomatic and 19 asymptomatic). All the isolates were of the serotype profile 0:1, 9, 12 and H:g, m (antigen phase I); all were sensitive to ampicillin, ceftriaxone, chloramphenicol, co-trimoxazole and ciprofloxacin. Plasmid profile analysis and restriction enzyme fragmentation patterns (REFPs), as generated with EcoRI and HindIII, of a 60 kb plasmid obtained from these isolates were all identical, confirming that the outbreak resulted from a single source of infection. Stratified statistical analysis of food-specific attack rates strongly implicated imported canned luncheon pork consumed by the inmates on 26 March 95 as the single most probable cause of the food poisoning [p < 10(6), Mantel-Haenszel weighted odds ratio (OR) = 14.33; 95% confidence interval (CI) = 6.20-33.15]. The median incubation period of this outbreak was 19.3 hours and the median duration of illness was three days. The outbreak was rapidly brought under control through prompt implementation of epidemic control measures which comprised active search for diarrheal cases, rectal swabbing of asymptomatic inmates, isolation of those found to be infected, and maintenance of a high standard of personal, food and environmental hygiene.

Disease Outbreaks↗

PubMed1997

[A report of outbreaks of pulmonary tuberculosis in two bars].

We experienced small outbreaks of M. tuberculosis infection in two bars. 9 patients were diagnosed as tuberculosis by identifying M. tuberculosis from their sputa. Six of them were regular customers or employees of the bar, one of them was a family members. Each outbreak within the two bars was suspected of the common source of infection, because one patient was a regular customer of the both bars. The analysis of restriction fragment length polymorphism (RFLP) was done on 5 strains of M. tuberculosis which were isolated from five of 9 patients. The result unexpectedly showed that 5 isolates were classified into 3 groups. Within each group, identical fingerprints were shown. It does mean that each outbreak in two bars was originated from independent source. There was also one relapsed case of tuberculosis. He was suspected of relapsed tuberculosis after a period of 7 years because of the similarity of drug resistance compared with his primary tuberculosis. It was cleared up that 3 different strains of M. tuberculosis were concerned with these outbreaks in the two bars. In this case, almost all patients were heavy drinkers, however, liver dysfunction and malnutrition were not recognized among them. These experiences indicate that a place like bar may be a space of infection of M. tuberculosis. We should always keep in mind a spread of tuberculosis in a place like a bar as one of problems in tuberculosis control.

Adult↗

PubMedDate not supplied

Salmonella gastroenteritis outbreak among workers from a tertiary care hospital in Mexico City.

OBJECTIVE: To describe an outbreak of Salmonella gastroenteritis among employees of the National Institute of Nutrition (INNSZ) of Mexico City during July, 1994. METHODS: Employees who developed diarrhea or fever associated with gastrointestinal symptoms starting on July 14th were included for study as well as 50 healthy controls. A questionnaire was applied to all, and they also provided a stool sample, along with other 80 asymptomatic people (included the kitchen workers) in whom only stool culture was done. RESULTS: Ninety-seven employees that ate regularly at the Hospital's cafeteria were affected by the outbreak, and 67 of them (69%) could be evaluated. Most of them were nurses (34%), and handymen (27%). Most common symptoms were abdominal pain (97%), diarrhea (95%), nausea (91%), and fever (89%). Cultures from suspicious food items were all negative, but stool cultures from 10/70 cases were positive for Salmonella enteritidis vs. 0/133 in the controls. The ten S. enteritidis isolates resulted identical either by serotyping and by rapid amplified polymorphic DNA (RAPD) analysis. Cultures from all kitchen employees were negative for S. enteritidis. Breakfast meal on July 14th was associated with the development of gastroenteritis (61/67 cases vs 26/50 controls, p < 0.001), and particularly with an egg-covered meat plate (61/62 vs 13/26 controls, p < 0.0001). CONCLUSIONS: This outbreak was probably caused by eggs contaminated with Salmonella, since no one of the kitchen personnel was found to be an asymptomatic carrier, and the implicated recipe allows for inappropriate cooking. Recommendations to improve cooking procedures must be added to the usual regulations to diminish the frequency of foodborne disease outbreaks in hospitals.

Adolescent↗

PubMed1997

A community outbreak of Vero cytotoxin producing Escherichia coli O157 infection linked to a small farm dairy.

A community outbreak of infection with Vero cytotoxin producing Escherichia coli O157 (VTEC 0157) occurred in a small area of north west England in 1996. An outbreak control team was established to investigate the outbreak and implement control measures. Nine people developed symptomatic infections with VTEC O157, and a further three were found to be excreting the bacteria. All were infected with the same genotype of VTEC O157. Three children under 5 years of age and one adult were admitted to hospital. One child developed haemolytic uraemic syndrome. All cases recovered. All primary cases had consumed milk from a particular farm dairy. No other common foods were identified. The farm dairy had a faulty pasteuriser and the potential for post pasteurisation contamination existed. VTEC O157 was isolated from a milk sock specimen and from two cows, but these strains differed from that infecting the cases. All local doctors and the public were alerted and advised about preventative measures. Distribution of unpasteurised milk from the farm was discontinued as was the sale of pasteurised milk when the faulty pasteuriser was discovered. A replacement pasteuriser was installed and checked before milk was released for human consumption. No conclusive evidence of the origin of this outbreak was found, but the farm was the most probable source. The investigations raised concerns about the distribution of VTEC O157 colonised dairy cattle, the natural history of such colonisation, the effectiveness of pasteurisation with respect to the elimination of VTEC O157, and the effectiveness of current legislation for the prevention and control of milkborne infection.

Adult↗

PubMed1997

A shipyard outbreak of salmonellosis traced to contaminated fruits and vegetables.

A large outbreak of food poisoning occurred in September 1996 and involved at least 116 workers at a shipyard in Jurong. Salmonella weltevreden was isolated from the stool specimens of 24 hospitalised cases and three food handlers, giving a total of 27 bacteriologically confirmed cases (25 symptomatic and two asymptomatic) in this outbreak. Based on a case-control analysis, a number of food items consumed on 23 and 24 September 1996 were implicated in the outbreak, viz. a vegetable dish (P < 0.01), watermelon juice (P < 0.01) and cut watermelon (P < 0.001), papaya (P < 0.001) and pineapple (P < 0.05). The median incubation period was 38 hours and the median duration of illness was two days. Four samples of cut fruits obtained from a food stall at the canteen were found to be positive for Salmonella weltevreden. (The antibiogram of all the strains isolated from food samples and stool cultures was similar, consistent with a common source of infection.) Extensive investigation suggested that contamination may have occurred through unauthorised use of industrial water for washing the fresh produce. Early recognition of the outbreak and prompt implementation of control measures prevented further spread of infection.

Adolescent↗

PubMedDate not supplied

[Considerations concerning the 1st outbreak of poliomyelitis in the city of Orizaba, Veracruz].

The objective is to present some deliberations on the paralytic poliomyelitis outbreak in the city of Orizaba, Veracruz. Fifty years after its occurrence, the original report of the first paralytic poliomyelitis epidemic in Mexico is presented herein. The detailed description of this outbreak by the authors reflects the devoted task of public health workers and clinicians who promptly identified an abnormal pattern of disease considered exotic in Mexico at that time. Unfortunately, this outbreak was the beginning of what proved to be an endemic disease with over 9,000 cases being reported in the ensuing ten years; some studies place the incidence figures three-to-fivefold higher. Fifty years after this outbreak, wild polio virus has been eradicated in Mexico and with it, the virtual eradication of paralytic poliomyelitis.

Adolescent↗

PubMedDate not supplied

[Analysis of a disease outbreak of brucellosis in slaughterhouse workers].

BACKGROUND: The appearance of an exceptional number of cases of Brucellosis at the end of 1996 in workers at a slaughterhouse led us to suspect an epidemic outbreak among this group. This study shows the methodology followed in the analysis of this outbreak as well as the results obtained. METHODS: 1.-Epidemiological description of the outbreak: number of animals with brucellosis slaughtered, collection of information from different sources on the number of those affected: from the mutual insurance company, the record of working days lost, an epidemiological monitoring system and a survey amongst the workers. 2.-A case and control study was designed in order to determine, firstly, non-occupational risks--ingestion of fresh cheese or milk and care of animals--and secondly, occupational risks, depending on the job normally undertaken. 3.-To verify this a retrospective cohort study was designed. The exposed group was made up by workers in the slaughter area and the unexposed group comprised the remainder: any worker giving a positive result to the Rose of Bengal test and IgM brucellosis antibodies in serum was considered as a case. RESULTS: The description of the outbreak enabled us to establish that the cases occurred at the moment when most animals were slaughtered, that only occupational risks were relevant, that there were more symptomatic cases than notified ones, and that the slaughter line operators showed higher rates of attack than the remainder of the workers. CONCLUSIONS: This study analyses the possible causal relationship between analyzed exposure and the appearance of cases of brucellosis in workers--a fact which backs the existing scientific evidence on the importance of the respiratory tract as a mechanism of transmission of this disease in the workplace.

Abattoirs↗

PubMed1998

The epidemiology of cryptosporidiosis: application of experimental sub-typing and antibody detection systems to the investigation of water-borne outbreaks.

A technique based on the analysis of banding patterns obtained by SDS-PAGE Western-blotting of an oocyst wall antigen obtained from faeces has been evaluated to subtype Cryptosporidium parvum Tyzzer, 1912. This technique appears to have sufficient stability to recognise multiple types of this parasite. A similar Western-blotting technique has also been used to assess antibody responses to cryptosporidial antigens in human sera. Two systems were developed: one against three antigens of apparent molecular weights 6, 14 and 17 kDa; the second against oocyst wall antigens of apparent molecular weights 57, 69, 75, 89, 128, 151 and 173 kDa. Antibodies to three antigens of apparent molecular weights 6, 14 and 17 kDa were most successful as diagnostic markers in that they were found in > 88% of convalescent phase sera from confirmed cryptosporidiosis patients and were uncommon (> or = 7%) in control subjects. Faecal samples from human and animal sporadic cases yielded a wide range of cryptosporidial antigen banding patterns. Samples from patients in a water-borne outbreak in South Devon (England) in 1995 also yielded a wide range of banding patterns including members within individual household family groups. These results are in contrast with those from samples collected from other defined geographical areas, including some from a second water-borne outbreak where much more homogeneous banding patterns were obtained. Sera collected for other purposes from apparently uninfected individuals 9 months after the South Devon 1995 outbreak were examined. Antibodies to the three antigens of molecular weights 6, 14 and 17 kDa were detected in 32-49% of individuals resident in the outbreak water supply area, and in 15-21% of those resident in an adjacent water supply area. The significance of these findings is discussed in relation to data obtained from epidemiological field studies.

Animals↗

PubMed1997

[Virological diagnosis of an outbreak of fever and rashes caused by parvovirus B19, Cuba, 1995].

The results obtained in the study of an a outbreak of fever and rash occurred in Havana City in March, 1995, are reported. Dengue, measles, rubella, herpes simplex, and Epstein Barr were discarded as causal agents of the outbreak in the samples of 35 patients. Parvovirus B19 was identified as the causing agent of the outbreak by the detection of IgM antibodies and the polymerase chain reaction technique (PCR). The infection produced by this agent was confirmed in 14/18 samples (77.7%) by some of the techniques used. This study makes reference to the first outbreak of Parvovirus B19 that was proved in Cuba.

Adult↗

PubMed1998

Epidemiological analysis defining concurrent outbreaks of Serratia marcescens and methicillin-resistant Staphylococcus aureus in a neonatal intensive-care unit.

OBJECTIVE: To describe the epidemiology, interventions, and molecular typing methods used during the investigation and control of concurrent outbreaks of Serratia marcescens and methicillin-resistant Staphylococcus aureus (MRSA) infections in a neonatal intensive-care unit (NICU). SETTING: A 206-bed women's and infants' hospital with a 48-bed NICU. DESIGN: A 22-week, prospective, descriptive study of all NICU infants with S marcescens or MRSA infection or colonization. Repetitive polymerase chain reaction (rep PCR) and pulsed-field gel electrophoresis (PFGE), respectively, were applied to the typing of S marcescens and MRSA isolates. INTERVENTIONS: Infants with S marcescens or MRSA infection or colonization were placed in isolation; all other infants were cohorted. A multidisciplinary task force implemented education for all hospital and medical staff regarding policies essential for outbreak control. Changes in physical setting and patient contact procedure were required to promote adherence to existing policies. RESULTS: Two premature infants had S marcescens infection, and five were colonized; rep PCR verified that both invasive and three of five colonizing isolates were related genotypically. Five bacteremic and 10 MRSA-colonized infants were identified; PFGE confirmed that 12 of the isolates had similar electrophoretic patterns. S marcescens infection was eliminated from the NICU 3 weeks after interventions were initiated. MRSA infections also were eliminated, and MRSA colonization fell to below pre-outbreak rates within 8 weeks. Despite a 100% increase in NICU patient days per month during the subsequent 2 years, no further clusters of S marcescens or MRSA infection have occurred. CONCLUSIONS: Concurrent outbreaks of S marcescens and MRSA in an NICU were confirmed by genotyping of strains. Control was achieved by isolation and cohorting of patients and strict adherence to NICU policies and procedures.

Disease Outbreaks↗

PubMed1987

Outbreak of carbon tetrachloride poisoning in a color printing factory related to the use of isopropyl alcohol and an air conditioning system in Taiwan.

Three workers from a color printing factory were admitted to community hospitals in 1985 with manifestations of acute hepatitis. One of the three had superimposed acute renal failure and pulmonary edema. An investigation was subsequently conducted at the plant to determine the etiology of the outbreak and the prevalence of liver disease among the remaining workers. Comprehensive medical evaluations were conducted, which included physical examinations, liver function tests, and serological screening for hepatitis. Seventeen of 25 workers from the plant had abnormal liver function tests 10 days after the outbreak, and a significant association was found between the presence of abnormal liver function tests and a history of recently having worked inside any of three rooms in which an interconnecting air conditioning system had been installed to cool the printing machines. After further investigation, it was determined that the incident occurred following inadvertent use of carbon tetrachloride to clean a pump in the printing machine. A simulation of the pump cleaning operation revealed ambient air levels of carbon tetrachloride of 300-500 ppm. Ultimately, it was concluded that the outbreak was in all likelihood due to the combined use of carbon tetrachloride and isopropyl alcohol in the cleaning operation. This outbreak underscores the importance of adopting appropriate industrial hygiene measures in a rapidly industrializing nation such as Taiwan.

1-Propanol↗

PubMed2000

Flexible spatial organization of urban foxes, Vulpes vulpes, before and during an outbreak of sarcoptic mange.

The social and spatial organization of urban fox groups prior to and during an outbreak of sarcoptic mange was compared with predictions derived from the resource dispersion hypothesis (RDH). We investigated the availability of three key resources. Neither daytime rest sites nor breeding sites appeared to be limited in availability. The availability of food deliberately supplied by local householders was examined by questionnaire surveys. The daily and weekly amount of food supplied was greatly in excess of the minimum requirements of a pair of foxes, but was consistent between territories. The availability of this food source increased markedly as a result of more people feeding the foxes. In agreement with the RDH, group size prior to the outbreak of mange increased from 2.25 animals (N=4) to 6.57 animals (N=7). Before the outbreak of mange, two territories were divided. Increased scavenge availability on smaller territories may have promoted these changes. Excluding these spatial changes, territories were very stable between years. After the outbreak of mange, group size declined as a direct result of mange-induced mortality. Surviving animals increased their ranges only after neighbouring groups had died out. Ranges did not increase in size in response to a decline in food availability. Nor were the increases in range size associated with the relinquishment of parts of the existing territory. These postmange changes are contrary to the RDH. Three factors may have promoted these changes: the elimination of interstitial space, the forced dispersal of young or future division of the territory. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed2000

Population outbreaks in a discrete world.

We present and analyze a simple three-patch host-parasitoid model where population growth is discrete. The model gives solutions that are qualitatively similar to the stable large-amplitude patterns in space found in reaction-diffusion theory. In the context of host-parasitoid interactions, the large-amplitude portions of the solution can be thought of as spatially localized host population outbreaks. Here, we show that the biological requirements for localized population outbreaks in a discrete world are identical to those found in reaction- diffusion theory. Furthermore, the model conveniently allows investigation into the robustness of these population outbreaks under the influence of density-dependent dispersal behavior. We find that localized population outbreaks in space can still occur with modest amounts of pursuit and aggregative behavior by parasitoids. We end by showing that evidence from a real host-parasitoid system is consistent with the predictions of the model.

Animals↗

PubMed1985

Multiple stable recurrent outbreaks and predictability in seasonally forced nonlinear epidemic models.

A seasonally forced nonlinear SEIR epidemic model is used to simulate small and large amplitude periodic outbreaks. The model is shown to exhibit bistable behavior for a fixed set of parameters. Basins of attraction for each recurrent outbreak are computed, and it is shown that the basins of two coexisting stable outbreaks are intertwined in a complicated manner. The effect of such a basin structure is shown to result in an obstruction in predicting asymptotically the type of outbreak given an uncertainty in the initial population of susceptibles and infectives.

Epidemiology↗

PubMed1978

The 1977 outbreak of bluetongue in Cyprus.

Bluetongue outbreaks, ranging from isolated cases to widespread infections, have occurred in Cyprus in about half of the years since 1924. Serious outbreaks occurred in 1924, 1939, 1943, 1946, 1951, and 1965. Most cases occurred in September, October, November and December. The last outbreak prior to 1977 was in 1969. Virus types isolated in the past were types 3 and 4. In 1977 the outbreak was serious, affecting 13.1 per cent of 27,837 in-contact sheep; these were scattered in 303 flocks of 65 villages throughout the Government-controlled area. The virus type isolated was type 4. Culicoides were involved in bluetongue transmission in the island.

Animals↗