bluuebunny/crossref_metadata_2025 huggingface dataset:
The study of infectious intestinal disease in England: risk factors for cases of infectious intestinal disease with Campylobacter jejuni infection
Authors: RODRIGUES L. C. , COWDEN J. M. , WHEELER J. G. , SETHI D. , WALL P. G. , CUMBERLAND P. , TOMPKINS D. S. , HUDSON M. J. , ROBERTS J. A. , RODERICK P. J.
Published: August 2008

This is a case-control study aimed at identifying risk factors for intestinal infection with Campylobacter jejuni. Cases were defined as subjects with diarrhoea occurring in community cohorts or presenting to General Practitioners (GPs) with Campylobacter jejuni in stools. Controls were selected from GP lists or cohorts, matched by age, sex, and GP practice. Travel abroad and consumption of chicken in a restaurant were statistically significantly associated with being a case. There was no statistically significant risk associated with consumption of chicken other than in restaurants nor with reported domestic kitchen hygiene practices. Consumption of some foods was associated with a lower risk of being a case. Most cases remained unexplained. We suggest that infection with low numbers of micro-organisms, and individual susceptibility may play a greater role in the causation of campylobacter infection than previously thought. It is possible that in mild, sporadic cases infection may result from cross contamination from kitchen hygiene practices usually regarded as acceptable. Chicken may be a less important vehicle of infection for sporadic cases than for outbreaks, although its role as a source of infection in both settings requires further clarification in particular in relation to the effect of domestic hygiene practices. The potential effect of diet in reducing the risk of campylobacteriosis requires exploration.
An outbreak of diarrhoea due to multiple antimicrobial-resistant Shiga toxin-producing Escherichia coli O26[ratio ]H11 in a nursery
Authors: HIRUTA N. , MURASE T. , OKAMURA N.
Published: August 2008

An outbreak due to Shiga toxin-producing Escherichia coli O26[ratio ]H11 (STEC) occurred at a nursery in southeastern Japan in 1997. Thirty-two children had watery or bloody diarrhoea but none of them suffered from haemolytic-uremic syndrome. All of the STEC O26 were isolated during the period from 23 July to 22 August from 24 children, 3 nurses, and 2 food samples. These organisms had stx1 and eae genes but none of the other genes for which we tested (stx2, bfp, and EAF plasmid). They also possessed multiple antimicrobial resistances, which were encoded by a transmissible plasmid, and showed mostly identical genomic pulsed-field gel electrophoretic patterns. The results of this investigation suggested that contaminated food was the main contributing factor to this multiple antimicrobial-resistant STEC O26 infection, and person-to-person transmission also contributed to the spread of this outbreak.
Frequency of failure to isolate Shigella spp. by the direct plating technique and improvement of isolation by enrichment in selenite broth
Authors: MIYAGI K. , TAKEGAKI Y. , NAKANO T. , NAKANO Y. , HONDA T. , SANO K.
Published: August 2008

In order to clarify the failure to isolate Shigella spp. by direct plating, we compared frequencies of Shigella spp. isolation by direct plating and by plating after enrichment in selenite broth. A total 67 strains were isolated in this study. The strains of 38 (56·7%) were isolated only by direct plating, and 25 (37·3%) strains were isolated by both direct plating and after enrichment. Four strains (6·0%) were isolated after enrichment but not by direct plating. Since 6% of isolated Shigella spp. were not isolated by direct plating, we recommend that direct plating and additional isolations from selenite broth should be performed. The significance concerning reduction of concentration of sodium selenite in enrichment broth is discussed.
A comparison of gastroenteritis in a general practice-based study and a community-based study
Authors: DE WIT M. A. S. , KORTBEEK L. M. , KOOPMANS M. P. G. , DE JAGER C. J. , WANNET W. J. B. , BARTELDS A. I. M. , VAN DUYNHOVEN Y. T. H. P.
Published: August 2008

We compared gastroenteritis cases that consulted a general practitioner (GP) with those who did not in a community-based study and also with those in a GP-based study. We aimed to identify factors associated with consultation, and with inclusion of cases by GPs, and secondly to study the effects on the frequency of detection of pathogens. Furthermore, we estimated the under-ascertainment by GPs. Both studies were performed in The Netherlands in the same population in an overlapping time-period. Overall, 5% of community cases consulted a GP. Cases who consulted suffered from more severe episodes than non-consulting cases. Inclusion of cases by GPs, instead of a study team, caused a selection of more severe cases with more chronic symptoms. When extrapolating data from GP-based studies, it should be taken into account that, in general practice, gastroenteritis due to bacteria and Giardia lamblia is a relatively large proportion of that in the community and gastroenteritis due to Norwalk-like viruses is a relatively small proportion. The incidence of gastroenteritis in general practices was estimated between 14 and 35 per 1000 person years.
Tattooing and risk for transfusion-transmitted diseases: The role of the type, number and design of the tattoos, and the conditions in which they were performed
Authors: DE A. NISHIOKA S. , GYORKOS T. W. , JOSEPH L. , COLLET J.-P. , MACLEAN J. D.
Published: August 2008

Tattoos have been shown to be associated with transfusion-transmitted diseases (TTDs), particularly hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. Very little is known about the association between different categories of tattoos and TTDs. In a cross-sectional study in Brazil, we studied 182 individuals with tattoos and assessed the odds of testing positive for a TTD according to tattoo type, number, design and performance conditions. Major findings were significant associations between an increasing number of tattoos and HBV infection (odds ratio (OR) of 2·04 for two tattoos and 3·48 for [ges ] 3 tattoos), having a non-professional tattoo and testing positive for at least one TTD (OR = 3·25), and having [ges ] 3 tattoos and testing positive for at least one TTD (OR = 2·98). We suggest that non-professional tattoos and number of tattoos should be assessed as potential deferral criteria in screening blood donors.
A multispecies model for the transmission and control of mastitis in dairy cows
Authors: WHITE L. J. , SCHUKKEN Y. H. , LAM T. J. G. M. , MEDLEY G. F. , CHAPPELL M. J.
Published: August 2008

Mastitis in dairy cows is a significant economic and animal welfare issue in the dairy industry. The bacterial pathogens responsible for infection of the mammary gland may be split into two main categories: major and minor pathogens. Infection with major pathogens generally results in clinical illness or strong inflammatory responses and reduced milk yields, whereas minor pathogen infection is usually subclinical. Previous investigations have considered the transmission of these pathogens independently. Experimental evidence has shown cross-protection between species of pathogens. In this study a mathematical model for the coupled transmission of major and minor pathogens along with their interaction via the host was developed in order to consider various methods for controlling the incidence of major pathogen infection. A stability analysis of the model equilibria provides explanations for observed phenomena and previous decoupled modelling results. This multispecies model structure has provided a basis for quantifying the extent of cross-protection between species and assessing possible control strategies against the disease.
Varicella transmission in two samples of children with different social behaviour in the State of São Paulo, Brazil
Authors: YU A. L. F. , AMAKU M. , BURATTINI M. N. , MASSAD E. , AZEVEDO R. S.
Published: August 2008

In order to establish the differences in transmission pattern of varicella-zoster virus (VZV), a comparative seroepidemiological study was carried out in two different children samples. Children aged 1–11 years, were randomly selected from state schools of São Paulo city, Brazil. Individuals aged 1–15 years were sampled by cluster from Caieiras city. Children aged 3 years or under from Caieiras were not attending school, while those from São Paulo were attending all-day nurseries or kindergarten. The presence of antibodies to VZV was analysed by ELISA technique. The force of infection and contact rate were determined by mathematical techniques. The average age of first infection was 2·87±0·14 years and 4·07±0·47 years for São Paulo and Caieiras, respectively. The average force of infection estimated was 0·29 year−1 for São Paulo and was 0·26 year−1 for Caieiras. The proportion of seropositivity and the force of infection were higher in São Paulo school children up to 3 years of age compared with Caieiras children, where the social contact starts later. In conclusion, social changes affecting contact among children may influence varicella epidemiology.
Monitoring patients in the community with suspected Escherichia coli O157 infection during a large outbreak in Scotland in 1996
Authors: WOOD R. , DONAGHY M. , DUNDAS S.
Published: August 2008

During outbreaks of Escherichia coli O157 a minority of patients with suspected infection develop haemolytic uraemic syndrome (HUS). The ability to identify this subgroup at an early stage is beneficial as mortality from HUS is high and may be influenced by intervention. During the 1996 Central Scotland E. coli O157 outbreak, of 886 patients from the community with suspected infection monitored at an outbreak clinic, nine developed HUS. We assessed factors associated with the development of HUS in this group. Children and the elderly were at increased risk of HUS. However, high white cell count was as least as good a predictor of HUS as age. High white cell counts predicted development of HUS with a sensitivity of 89%, specificity of 87%, positive predictive value of 7% and a negative predictive value of over 99%. We have used the results from this study along with other currently available evidence to propose a monitoring protocol for patients from the community with suspected E. coli O157 infection.
Hepatitis C virus infection among teenagers in an endemic township in Taiwan: epidemiological and clinical follow-up studies
Authors: HUANG J. F. , LU S. N. , CHUE P. Y. , LEE C. M. , YU M. L. , CHUANG W. L. , WANG J. H. , DAI C. Y. , CHEN I. L. , SHIH C. H. , CHANG W. Y.
Published: August 2008

The aim of the study was to elucidate the epidemiological features of Hepatitis C virus (HCV) infection among teenagers in an endemic area by conducting a mass screening study. We also investigated the clinical outcome of the anti-HCV-positive subjects by conducting subsequent short-term and long-term follow-up studies. All 2837 students of two junior middle schools in Tzukuan, aged 13–16 years, were invited to be screened for anti-HCV, HBsAg, AST and ALT in October 1995. A total of 2726 (96%) students responded. Anti-HCV, HCV RNA and aminotransferase levels were evaluated among anti-HCV-positive students 1 month and 30 months later, respectively. A total of 38 (1·4%; M/F = 22/16) participants were anti-HCV-positive. The anti-HCV-positive students had higher rates of exposures to transfusion, anti-HCV-positive families and surgery. The prevalence (2·8%) of the 7 maritime villages was markedly higher than that (0·7%) of the other 8 villages (P < 0·001). Subsequent follow-up studies demonstrated that there might be 5 cases of acute or recent HCV infection, and 6 cases who had recovered from chronic HCV infection.
Prevalence of Neisseria meningitidis carriers in the school population of Catalonia, Spain
Authors: DOMÍNGUEZ A. , CARDEÑOSA N. , IZQUIERDO C. , SÁNCHEZ F. , MARGALL N. , VÁZQUEZ J. A. , SALLERAS L.
Published: August 2008

The aim of this study was to determine the prevalence of healthy Neisseria meningitidis pharyngeal carriers in a representative sample of the Catalonian school population, as well as its associated factors. The sample was divided into age groups: [les ]5, 6–7 and 13–14 years old. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. Oropharyngeal swabs were collected with a cotton-tipped swab in an Amies transport medium and cultured on Thayer Martin plates at 35 °C in 5% CO2. The isolates were serogrouped and sero/subtyped. Of the 1406 children studied, 75 (5·34%) meningococcal carriers were detected: 63 B (4·5%), 9 non groupable (0·7%), 2 29E (0·1%) and 1X (0·07%). No serogroup C meningococci were found in this study, probably due to the high A+C vaccination coverage of up to 68·9% in children 6–7 years old. Bivariate analysis identified six statistically significant risk factors for meningococcal carriage: increasing age, recent upper respiratory tract infection, previous antibiotic treatment, number of students in the class, size of the classroom and social class. Multivariate analysis found that only age and previous antibiotic treatment remained statistically significant when the other factors were controlled.
An outbreak of hepatitis A amongst injecting drug users
Authors: O’DONOVAN D. , COOKE R. P. D. , JOCE R. , EASTBURY A. , WAITE J. , STENE-JOHANSEN K.
Published: August 2008

This descriptive study investigated an outbreak of hepatitis A virus (HAV) infection among injecting drug users (IDUs) and their contacts. Twenty-seven cases of acute HAV infection were identified in a 5-month period. Connections with the local injecting drug using (IDU) population were established for 25 of the cases of whom 14 admitted to injecting drug use. HAV RNA genotyping revealed two HAV variants, closely related to variants found in Scandinavian IDUs and in South East Asia. The study demonstrates that once HAV enters the IDU population extensive outbreaks are possible. We recommend that all IDUs should be tested for HAV and hepatitis B virus (HBV) infections and offered combined hepatitis A and B vaccines if non-immune.
Seroprevalence of parvovirus B19 in urban Chilean children and young adults, 1990 and 1996
Authors: ABARCA K. , COHEN B. J. , VIAL P. A.
Published: August 2008

An immunofluorescence test for detecting parvovirus B19 IgG was developed by infecting insect cells with recombinant baculovirus expressing the capsid protein VP1. The test was used to study the prevalence of antibodies in 725 healthy children and young adults living in Santiago, Chile. In total, 248 sera were taken in 1990 and 477 in 1996. The seroprevalence was low in children less than 5 years old (3% in 1990 and 21% in 1996). It rose during school age to a prevalence around 50%, reaching 60% in young adults. No differences were found between genders. There was a statistically significant higher seroprevalence in the low socio-economic status group in 1990 samples, but this was not observed in 1996. The higher prevalence observed in children less than 5 years of age in 1996 compared with 1990 could be explained by the occurrence of intervening epidemics of parvovirus B19 infection.
A controlled estimate of the risk of HIV infection in Ethiopian children with tuberculosis
Authors: BERGGREN PALME I. , GUDETTA B. , DEGEFU H. , MUHE L. , BRUCHFELD J. , GIESECKE J.
Published: August 2008

To quantify the risk of human immunodeficiency virus (HIV) infection in children with tuberculosis (TB) a hospital-based, 1-year prospective, case-control study was performed in Addis Ababa, Ethiopia. Children with TB were compared to a control group of children admitted for elective surgery. The control group was also compared to a recent census of the background population. The crude odds ratio for HIV infection was 8·6 (95% CI 2·2–73). After adjustment for possible confounders in a multivariate regression model, the odds ratio for HIV infection in children with TB was found to be 12·7 (95% CI 2·9–55). Of several independent determinants of TB assessed in the study, this association was the strongest. Until HIV transmission has reached its peak, an increasing burden of dual infection among Ethiopian children is to be expected.
HIV disease among immigrants coming to Italy from outside of the European Union: a case-control study of epidemiological and clinical features
Authors: MANFREDI R. , CALZA L. , CHIODO F.
Published: August 2008

The epidemiological, clinical and therapeutic features of HIV disease diagnosed in 41 immigrants from outside of the European Union (EU), were compared with those of 123 Italian and EU patients, in a cross-sectional case-control study, with individuals matched according to age and gender. In total 4·15% of our patients came from outside of the EU (51·2% of them from subsaharan Africa), with a proportional predominance of females, and heterosexual and perinatal transmission of HIV disease (P < 0·0001 and P < 0·02, respectively). Compared with Italian and EU subjects, patients coming from abroad had a shorter duration of known HIV infection (P < 0·001), but only some subjects were aware of their HIV disease prior to immigration, or acquired HIV infection only after coming to Italy (14·6% and 12·2%, respectively). No cases of HIV-2 infection or co-infection were detected in either study group. Compared with controls, patients coming from outside of the EU had a comparable clinical and immunological status, and had similar antiretroviral therapy, which was administered earlier (P < 0·0001), and proved better tolerated (P < 0·04), than in Italian and EU subjects. The apparently more limited virological response (as expressed by a higher mean plasma viral load, and a lower rate of viral suppression at the last visit; P < 0·001 and P < 0·05, respectively), was probably a bias due to the shorter mean overall follow-up time (P < 0·0001), and the shorter mean duration of antiretroviral treatment (11·1±2·2 months of immigrants vs. 16·2±6·7 months of controls; P < 0·0001).
Race/ethnicity and other risk of factors associated with cryptosporidiosis as an initial AIDS-defining condition in California, 1980–99
Authors: KHALAKDINA A. , TABNAK F. , SUN R. K. P. , COLFORD J. M.
Published: August 2008

To study whether African-Americans are less likely than whites to present with cryptosporidiosis as an AIDS-defining condition (ADC), a case-control study was conducted using a large, population-based surveillance registry of AIDS patients in California. Data from January 1980 through June 1999 were analysed using risk factor stratification and multivariate logistic regression to evaluate confounding by other risk factors such as gender, injection drug use (IDU), CD4 counts, age and sexual orientation. Cases included 1373 subjects with cryptosporidiosis as an ADC and controls included 97419 subjects with other ADC. The results indicate a significantly lower risk for presentation with cryptosporidiosis as an ADC among African-Americans compared with whites (OR vs. whites = 0·5, 95% CI 0·4, 0·7). Additionally, there is evidence that heterosexuals are less likely than homosexual/bisexual males to present with cryptosporidiosis (OR = 0·5, 95% CI 0·4, 0·7). Our analyses also suggest a decreasing risk with increasing age. The possibility that there may be biologic factors or differential lifetime exposures that account for the difference between the racial/ethnic groups merits further investigation.
Detection of Aeromonas caviae in the common housefly Musca domestica by culture and polymerase chain reaction
Authors: NAYDUCH D. , HONKO A. , NOBLET G. P. , STUTZENBERGER F.
Published: August 2008

Aeromonas caviae has been implicated in diarrhoeal disease of livestock and humans. The potential role of houseflies in the epidemiology of this pathogen was investigated by examining the prevalence of A. caviae in houseflies collected from two South Carolina farms and one restaurant. Isolation was accomplished by culture of flies in alkaline peptone water followed by identification with Aeromonas-specific PCR using novel primers (APW–PCR). All isolates cultured from houseflies were identified as A. caviae by biochemical characteristics and direct sequencing ∼ 800 bp of the 16S rRNA gene. Aeromonas caviae was detected in 78% (272/349) dairy farm flies, 55% (54/99) pig farm flies and 39% (77/200) restaurant flies. Faeces from cows and pigs at the farms also were positive for A. caviae (58% and 100%, respectively). The APW–PCR method provided a rapid, convenient way to identify A. caviae from faeces and houseflies that contained hundreds of bacterial species.
Risk factors in HIV-associated diarrhoeal disease: the role of drinking water, medication and immune status
Authors: EISENBERG J. N. S. , WADE T. J. , CHARLES S. , VU M. , HUBBARD A. , WRIGHT C. C. , LEVY D. , JENSEN P. , COLFORD J. M.
Published: August 2008

In a cross-sectional survey of 226 HIV-infected men, we examined the occurrence of diarrhoea and its relationship to drinking water consumption patterns, risk behaviours, immune status and medication use. Diarrhoea was reported by 47% of the respondents. Neither drinking boiled nor filtered water was significantly associated with diarrhoea (OR = 0·5 [0·2, 1·6], 1·2 [0·6, 2·5] respectively), whereas those that drank bottled water were at risk for diarrhoea (OR = 3·0 [1·1, 7·8]). Overall, 47% always or often used at least one water treatment. Of the 37% who were very concerned about drinking water, 62% had diarrhoea, 70% always or often used at least one water treatment. An increase in CD4 count was protective only for those with a low risk of diarrhoea associated with medication (OR = 0·6 [0·5, 0·9]). A 30% attributable risk to diarrhoea was estimated for those with high medication risk compared to those with low medication risk. The significant association between concern with drinking water and diarrhoea as well as between concern with drinking water and water treatment suggests awareness that drinking water is a potential transmission pathway for diarrhoeal disease. At the same time we found that a significant portion of diarrhoea was associated with other sources not related to drinking water such as medication usage.
PCR–IMS detection and molecular typing of Cryptosporidium parvum recovered from a recreational river source and an associated mussel (Mytilus edulis) bed in Northern Ireland
Authors: LOWERY C. J. , NUGENT P. , MOORE J. E. , MILLAR B. C. , XIRU X. , DOOLEY J. S. G.
Published: August 2008

PCR–IMS was used to detect Cryptosporidium spp. in environmental water samples in Northern Ireland which had previously tested negative by a conventional IFA staining method. Oocysts of C. parvum detected in river water and final treated sewage effluent collected from various sites along the river Lagan were identified as genotype 2 (animal origin) based on polymorphisms observed at the thrombospondin related adhesion protein gene locus. Similarly, genotype I (human origin) oocysts of C. parvum were detected in the marine filter feeder mussel, Mytilus edulis, collected from the shores of Belfast Lough. Detection of the human genotype of Cryptosporidium in mussels destined for human consumption identifies the organism's serious potential as a foodborne pathogen. This work highlights the possible value of monitoring filter feeder systems, in conjunction with specific molecular epidemiological tools, as an alternative monitoring system for the parasite within the aquatic environment.
Epidemiology of hospital-acquired infections in cirrhotic patients: effect of carriage of methicillin-resistant Staphylococcus aureus and influence of previous antibiotic therapy and norfloxacin prophylaxis
Authors: CAMPILLO B. , DUPEYRON C. , RICHARDET J. P.
Published: August 2008

We assessed the prevalence of carriage of methicillin-resistant Staphylococcus aureus (MRSA) in anterior nares and stools, and of third-generation cephalosporin resistant enterobacteriaceae and non-fermenting Gram-negative bacilli (RE/RNF) in stools of 748 hospitalized long-stay cirrhotic patients. We also evaluated the consequences of carriage on the epidemiology of hospital-acquired spontaneous bacterial peritonitis, bacteraemia and urinary tract infection (UTI) in these patients. The prevalence of carriage of MRSA and RE/RNF was 16·7% and 14·7% respectively. Whereas RE/RNF carriage did not lead to an increased risk of infection due to RE/RNF, the overall risk of infections caused by MRSA was more than tenfold higher in MRSA carriers. MRSA and RE/RNF carriers had received prior antibiotic therapy to a greater extent than non-carriers (P < 0·001) and MRSA carriers had received prior norfloxacin prophylaxis to a greater extent than the two other groups (P < 0·02). The mortality rate during hospital stay was higher in MRSA and RE/RNF carriers than in non-carriers (P < 0·001). Pugh score (P < 0·0001), age (P < 0·0001), MRSA carriage (P = 0·0018) and bacteraemia (P = 0·0017) were associated independently with mortality. MRSA carriage in hospitalized cirrhotic patients leads to the emergence of infections due to this strain, mainly SBP and bacteraemia. Prior antibiotic therapy and norfloxacin prophylaxis increase the risk of carriage of MRSA.
Epidemiology of meningococcal meningitis in Angola, 1994–2000
Authors: GASPAR M. , LEITE F. , BRUMANA L. , FÉLIX B. , STELLA A. A.
Published: August 2008

We describe six meningococcal disease outbreaks that occurred in Angola during the period 1994–2000. In total, 7140 cases were documented. The age groups most affected were 15–29 years and 5–14 years; there were no differences in incidence between the sexes. Circulation of both serogroup A and sporadic serogroup B strains was demonstrated. Mass vaccination campaigns with A+C meningococcal polysaccharide vaccine were implemented, except in Yambala province in 1999 where insecure conditions precluded this intervention.

Outbreaks of serogroup A meningococcal disease in Angola may indicate an extension of these epidemics outside the meningitis belt. Mass vaccination campaigns stopped the Angolan epidemics within weeks. Civil conflict and displaced persons living in crowded areas created serious difficulties for surveillance and impeded timely public health responses.
Increase in meningococcal disease associated with the emergence of a novel ST-11 variant of serogroup C Neisseria meningitidis in Victoria, Australia, 1999–2000
Authors: TRIBE D. E. , ZAIA A. M. , GRIFFITH J. M. , ROBINSON P. M. , LI H. Y. , TAYLOR K. N. , HOGG G. G.
Published: August 2008

In the years 1999–2000, there was an increase in the incidence of meningococcal disease in Victoria, largely caused by Neisseria meningitidis serogroup C. This change was associated with a shift in age distribution of cases, with relatively more disease appearing in the 15–29 year age group, and with 40/58 serogroup C isolates in 2000 exhibiting a new macrorestriction pattern (pattern A). Thirty-four of 52 pattern A isolates tested displayed the novel phenotype C:2a:P1.4, and were consistently porA VR type P1.7-2,4 by DNA sequencing. Nine of 10 representative pattern A isolates analysed displayed a housekeeping gene allele profile (ST-11) that is characteristic of the electrophoretic type (ET)-15 variant that has caused outbreaks in Canada, the Czech Republic and Greece. Meningococci belonging to the ST-11 complex that were isolated in Victoria prior to 1999 did not display either restriction pattern A or PorA VR type P1.7-2,4.
Molecular subtyping of Staphylococcus aureus from an outbreak associated with a food handler
Authors: WEI H.-L. , CHIOU C.-S.
Published: August 2008

On 6 May 2000, a staphylococcal food poisoning outbreak occurred at a high school, affecting 10 of the 356 students who attended the breakfast. Twenty-seven Staphylococcus aureus isolates, producing enterotoxin A (SEA), SEB-, or non-SEA-E, were recovered from 7 patients, 2 food handlers and left-overs. To investigate the outbreak, we genotyped the isolates by using pulsed-field gel electrophoresis (PFGE) and three PCR-based techniques: inter-IS256 PCR typing, protein A gene (spa) typing, and coagulase gene restriction profile (CRP) analysis. Our results show that PFGE was the most discriminatory technique, whereas the three PCR-based techniques were insufficient in the discriminatory power to distinguish the S. aureus isolates from the outbreak. Based on the enterotoxin-producing types and the results of genotyping, three distinct types of strains (A1111, B2221 and N3221) were designated. Both the A1111 and B2221 strains were found in the specimens from the patients and a hand lesion of a food handler, suggesting that the source of contamination for the outbreak was most likely originated from a food handler.
An outbreak of multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium, DT104L linked to dried anchovy in Singapore
Authors: LING M. L. , GOH K. T. , WANG G. C. Y. , NEO K. S. , CHUA T.
Published: August 2008

Multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium DT104L was first reported in Singapore from mid-July to mid-October 2000. Salmonella strains isolated from clinical laboratories were submitted to a reference laboratory for serotyping, phage-typing and pulsed-field gel electrophoresis (PFGE) using XbaI restriction endonuclease. An epidemiological investigation was conducted to determine the source of infection and mode of transmission using a structured questionnaire. A total of 33 cases involving mainly infants and toddlers were detected in the 3-month long outbreak. The outbreak strain was of the R-type ACGSTSu, i.e. resistant to ampicillin, chloramphenicol, gentamicin, streptomycin, tetracycline and sulphonamide. PFGE showed all isolates had an indistinguishable pattern, indicating a common source of infection. Consumption of imported dried anchovy was found to be the vehicle of transmission after adjusting for all confounding variables in the case-control study using stepwise logistic regression (OR 25·6; 95% CI 3·9–167·9; P = 0·001). Imported dried seafood should be properly processed, packed, labelled, and thoroughly cooked to prevent transmission of multidrug-resistant S. Typhimurium.
Protecting the vaccinating population in the face of a measles epidemic: assessing the impact of adjusted vaccination schedules
Authors: van den HOF S. , WALLINGA J. , WIDDOWSON M.-A. , CONYN-VAN SPAENDONCK M. A. E.
Published: August 2008

We investigated which vaccination schedule gives best protection to the vaccinating population, in case there is a measles epidemic in an area with low vaccine coverage. We considered combinations of an early measles vaccination (none, at 6 months or at 9 months), a measles–mumps–rubella (MMR) vaccination around the first birthday (at either 11 or 14 months), and MMR vaccination at an older age (at either 4 or 9 years). The different estimates on measures of protection (percentage of susceptibles, number of reported cases in an epidemic year, percentage of lifetime spent susceptible) relied on a mathematical model of decline of maternal antibody levels with age, and the impact of that antibody level on seroconversion and immunity. Model parameters were estimated from a Dutch population-based serological survey on measles antibodies. Different measures of protection favoured different vaccination schedules, but dropping the age of second MMR vaccination prevents considerably more cases than an extra early measles vaccination or dropping the age of first MMR vaccination.
Modelling death rates for carriers of hepatitis B
Authors: DICKINSON J. A. , WUN Y. T. , WONG S. L.
Published: August 2008

Hepatitis B carriers who acquired the infection perinatally die from hepatocellular carcinoma (HCC) and cirrhosis at high rates. Published cohort studies are largely limited to males and are too small to estimate the age-specific risk of death. We therefore used routinely collected Hong Kong data to estimate the risks. Deaths were partitioned between carriers and non-carriers, then current life table calculations determined life expectancy and probability of dying from HCC or cirrhosis. HCC is the dominant cause of death for male carriers in middle adulthood with a lifetime risk of 27% for HCC compared to 4% for females. Predicted life expectancy is 72 years for male carriers, compared to 79 years for non-carriers. Female carriers have a life expectancy of 81 years and non-carriers 83 years. This model probably applies to all southern Chinese populations and emigrants with similar life history, and other populations that acquired infection early in life.
A survey of Nipah virus infection among various risk groups in Singapore
Authors: CHAN K. P. , ROLLIN P. E. , KSIAZEK T. G. , LEO Y. S. , GOH K. T. , PATON N. I. , SNG E. H. , LING A. E.
Published: August 2008

Following the Nipah virus (NV) outbreak in March 1999 in Singapore, a serological survey was undertaken to screen individuals potentially exposed to NV. Blood samples were tested for NV IgM, IgG and neutralizing antibodies. Twenty-two (1·5%) of 1469 people tested had antibodies suggesting NV infection. Although 12 of the 22 infected people (54·6%) were symptomatic, the remaining 10 (45·4%) were clinically well and had no past history of compatible pulmonary or neurological disease. Clinical and serological findings suggested three people had been infected with NV before the outbreak was recognized. All those who were infected were male abattoir workers. None of the people who had contact with horses, and no healthcare workers exposed to infected patients and their specimens had detectable antibodies. This study provides evidence that NV causes asymptomatic infection. All of the antibody positive individuals had direct contact with pigs and there was no evidence of human to human transmission.
Transmission dynamics and mechanisms of endemicity of scrapie in the UK sheep population
Authors: TRUSCOTT J. E. , FERGUSON N. M.
Published: August 2008

Scrapie is a fatal neurological disease of sheep which is endemic in the United Kingdom. It is one of the family of transmissible spongiform encephalopathies (TSEs) that includes BSE. In this paper, we developed a micro-simulation model for scrapie in the UK sheep population, incorporating the genetic and structural diversity of the population and infectious contact between flocks through trading. The simulation was fitted to epidemiological data from a range of sources. We found a detection/reporting probability of 16% (95% CI 12–17) for animals dying of scrapie. Prevalence of infected animals in the population was about 0·15%. Infected individuals were found in 9% of flocks overall, rising to 60% in Shetland and 75% in Swaledale flocks. Mean values of R0 for flocks varied with breed from 2·43 (Shetland) to 0·21 (Suffolk). We also examined the possible long-term persistence of scrapie in the UK flock in the absence of any intervention.
Control of scrapie in the UK sheep population
Authors: TRUSCOTT J. E. , FERGUSON N. M.
Published: August 2008

Scrapie is a fatal transmissible spongiform encephalopathy (TSE) of sheep, endemic in the UK for centuries. Interest in the disease has been heightened over the last decade by the possibility of the related BSE being transmissible to and between sheep and a range of control interventions has been proposed and implemented. In this paper, we examined the effect of these policies and their components on observed case rate, susceptible allele frequency and R0 within the framework of a large simulation model of the British sheep population and its breeding and trading structure. We compared interventions with the natural fade-out of scrapie in the population through loss of susceptible genotypes in the absence of control. We compare the results of interventions with the natural course of the scrapie epidemic. Our model suggested that scrapie will persist in the national flock for 300–400 years with the impact on gene frequencies confined largely to high case-rate breeds, such as Shetland and Swaledale. We found the National Scrapie Plan (NSP) to be the most effective in terms of the removal of both susceptible genotypes and scrapie from the population. Complete eradication of scrapie can be achieved within 32 years (95% CI 23–43 years). The Compulsory Scrapie Flock Scheme (CSFS) is as effective as the NSP in reducing the observed case rate but has a limited impact on the frequencies of susceptible genotypes in the population overall. In combination with the NSP, eradication of scrapie is achieved >10 years faster. Of the components of the CSFS, the breeding and culling aspects are each almost as effective as the full policy, with trading restrictions contributing little. We have speculated on the impact of control measures on the possibility BSE infection within the national flock by examining their effect on flock R0 for BSE across different breeds.
Molecular analysis of high-level ciprofloxacin resistance in Salmonella enterica serovar Typhi and S. Paratyphi A: need to expand the QRDR region?
Authors: CAPOOR M. R. , NAIR D. , WALIA N. S. , ROUTELA R. S. , GROVER S. S. , DEB M. , AGGARWAL P. , PILLAI P. K. , BIFANI P. J.
Published: August 2008

Fourteen strains of S. Typhi (n=13) and S. Paratyphi A (n=1) resistant to ciprofloxacin were compared with 30 ciprofloxacin decreased-susceptibility strains on the basis of qnr plasmid analysis, and nucleotide substitutions at gyrA, gyrB, parC and parE. In ciprofloxacin-resistant strains, five S. Typhi and a single S. Paratyphi A showed triple mutations in gyrA (Ser83→Phe, Asp87→Asn, Glu133→Gly) and a novel mutation outside the quinolone resistance determining region (QRDR) (Met52→Leu). Novel mutations were also discovered in an isolate (minimum inhibitory concentration 8 μg/ml) in gyrA gene Asp76→Asn and outside the QRDR Leu44→Ile. Out of 30 isolates with reduced susceptibility, single mutation was found in 12 strains only. Genes encoding qnr plasmid (qnr A, qnr B, AAC1-F) were not detected in ciprofloxacin-resistant or decreased-susceptibility strains. Antimicrobial surveillance coupled with molecular analysis of fluoroquinolone resistance is warranted for reconfirming novel and established molecular patterns of resistance, which is quintessential for reappraisal of enteric fever therapeutics.
Differences in the susceptibility of dromedary and Bactrian camels to foot-and-mouth disease virus
Authors: LARSKA M. , WERNERY U. , KINNE J. , SCHUSTER R. , ALEXANDERSEN G. , ALEXANDERSEN S.
Published: August 2008

In this study, two sheep, eight dromedary camels and two Bactrian camels were inoculated with foot-and-mouth disease virus (FMDV) type A SAU 22/92. Five naive dromedary camels and four sheep were kept in direct or indirect contact with the inoculated camels. The inoculated sheep, which served as positive controls, displayed typical moderate clinical signs of FMD and developed viraemia and high antibody titres. The presence of the virus was also detected in probang and mouth-swab samples for several days after inoculation. In contrast, the inoculated dromedary camels were not susceptible to FMDV type A infection. None of them showed clinical signs of FMD or developed viraemia or specific anti-FMDV antibodies despite the high dose of virus inoculated. All the contact sheep and contact dromedaries that were kept together with the inoculated camels remained virus-negative and did not seroconvert when tested up to 28 days post-inoculation (p.i.). In comparison with the non-susceptible dromedaries, the two inoculated Bactrian camels showed moderate to severe clinical signs of FMD; however, the clinical signs of FMD appeared rather late, between 8 and 14 days p.i., compared to the inoculated sheep. Characteristic FMD lesions in the Bactrian camels, accompanied with severe lameness, were only observed on the hind feet. The presence of the virus in the serum samples of both Bactrian camels was detected by real-time RT–PCR in one of the animals on days 3 and 7 p.i. and in the second animal from days 1 to 3 p.i. and subsequently again on day 21 p.i. The Bactrian camels developed high titres of antibodies to the inoculated FMDV which appeared at 7–10 days p.i. and lasted up to 130 days p.i. Only low and transient amounts of FMDV were detected in the mouth-swab and probang samples collected from both Bactrian camels.
An outbreak ofSalmonellaTyphimurium 9 at a school camp linked to contamination of rainwater tanks
Authors: FRANKLIN L. J. , FIELDING J. E. , GREGORY J. , GULLAN L. , LIGHTFOOT D. , POZNANSKI S. Y. , VALLY H.
Published: August 2008

In March 2007, an outbreak of gastroenteritis was identified at a school camp in rural Victoria, Australia, affecting about half of a group of 55 students. A comprehensive investigation was initiated to identify the source. Twenty-seven attendees were found to have abdominal pain, diarrhoea and nausea (attack rate 49%). Of 11 faecal specimens tested all were positive forSalmonellaTyphimurium definitive phage type 9 (DT9). Of four samples taken from the untreated private water supply, two were positive for DT9. Drinking water from containers filled from rainwater tanks [relative risk (RR) 3·2,P=0·039] and participation in two recreational activities – flying fox (RR 5·3,P=0·011), and beam-balance (RR 3·9,P=0·050) – were indicative of a link with illness. Environmental and epidemiological investigations suggested rainwater collection tanks contaminated with DT9 as being the cause of the outbreak. Increased use of rainwater tanks may heighten the risk of waterborne disease outbreaks unless appropriate preventative measures are undertaken.
Weaving a web
Authors: HINZE RALF , JEURING JOHAN
Published: August 2008

Suppose, you want to implement a structured editor for some term type, so that
the user can navigate through a given term and perform edit actions on subterms.
In this case you are immediately faced with the problem of how to keep track of
the cursor movements and the user's edits in a reasonably efficient manner. In a
previous pearl, Huet (1997) introduced a simple data structure, the Zipper, that
addresses this problem – we will explain the Zipper briefly in section 2. A drawback
of the Zipper is that the type of cursor locations depends on the structure of the
term type, i.e. each term type gives rise to a different type of location (unless you
are working in an untyped environment). In this pearl, we present an alternative
data structure, the web, that serves the same purpose, but that is parametric in the
underlying term type. Sections 3–6 are devoted to the new data structure. Before we
unravel the Zipper and explore the web, let us first give a taste of their use.
Monadic encapsulation of effects: a revised approach (extended version)
Authors: MOGGI E. , SABRY AMR
Published: August 2008

Launchbury and Peyton Jones came up with an ingenious idea for embedding regions of
imperative programming in a pure functional language like Haskell. The key idea was based
on a simple modification of Hindley-Milner's type system. Our first contribution is to propose
a more natural encapsulation construct exploiting higher-order kinds, which achieves the
same encapsulation effect, but avoids the ad hoc type parameter of the original proposal. The
second contribution is a type safety result for encapsulation of strict state using both the
original encapsulation construct and the newly introduced one. We establish this result in a
more expressive context than the original proposal, namely in the context of the higher-order
lambda-calculus. The third contribution is a type safety result for encapsulation of lazy state
in the higher-order lambda-calculus. This result resolves an outstanding open problem on
which previous proof attempts failed. In all cases, we formalize the intended implementations
as simple big-step operational semantics on untyped terms, which capture interesting
implementation details not captured by the reduction semantics proposed previously.
Normalization by evaluation with typed abstract syntax
Authors: DANVY OLIVIER , RHIGER MORTEN , ROSE KRISTOFFER H.
Published: August 2008

In higher-order abstract syntax, the variables and bindings of an object language are
represented by variables and bindings of a meta-language. Let us consider the simply
typed λ-calculus as object language and Haskell as meta-language. For concreteness,
we also throw in integers and addition, but only in this section.
DrScheme: a programming environment for Scheme
Authors: FINDLER ROBERT BRUCE , CLEMENTS JOHN , FLANAGAN CORMAC , FLATT MATTHEW , KRISHNAMURTHI SHRIRAM , STECKLER PAUL , FELLEISEN MATTHIAS
Published: August 2008

DrScheme is a programming environment for Scheme. It fully integrates a graphics-enriched
editor, a parser for multiple variants of Scheme, a functional read-eval-print loop, and an
algebraic printer. The environment is especially useful for students, because it has a tower
of syntactically restricted variants of Scheme that are designed to catch typical student
mistakes and explain them in terms the students understand. The environment is also useful
for professional programmers, due to its sophisticated programming tools, such as the static
debugger, and its advanced language features, such as units and mixins. Beyond the ordinary
programming environment tools, DrScheme provides an algebraic stepper, a context-sensitive
syntax checker, and a static debugger. The stepper reduces Scheme programs to values,
according to the reduction semantics of Scheme. It is useful for explaining the semantics
of linguistic facilities and for studying the behavior of small programs. The syntax checker
annotates programs with font and color changes based on the syntactic structure of the
program. On demand, it draws arrows that point from bound to binding occurrences of
identifiers. It also supports α-renaming. Finally, the static debugger provides a type inference
system that explains specific inferences in terms of a value-flow graph, selectively overlaid on
the program text.
Democratic Consolidation in Korea: A Trend Analysis of Public Opinion Surveys, 1997–2001
Authors: Shin Doh Chull
Published: August 2008

The Republic of Korea (Korea hereinafter) has been widely regarded as one of the most vigorous and analytically interesting third-wave democracies (Diamond and Shin, 2000: 1). During the first decade of democratic rule, Korea has successfully carried out a large number of electoral and other reforms to transform the institutions and procedures of military-authoritarian rule into those of a representative democracy. Unlike many of its counterparts in Latin America and elsewhere, Korea has fully restored civilian rule by extricating the military from power. As is the case in established democracies of North America and Western Europe, free and competitive elections have been regularly held at all the different levels of the government. In the most recent presidential election, held in December 1997, Korea also established itself as a mature electoral democracy by elevating an opposition party to political power. In Korea today, there is general agreement that electoral politics has become the only possible political game in town.