To estimate the prevalence and distribution of salmonellae, especially Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis), in Western Japan, an investigation was conducted of the chicken industry and environmental sources between 1995 and 1998. Salmonellae were isolated from 34 of 90 samples (37·8 %) of raw chicken parts, 34 of 98 faecal samples (34·7 %) at 35 broiler farms, 11 of 59 samples (18·6 %) of liquid eggs, and from 71 of 272 samples (26·1 %) of swab specimens from equipment and cracked or faecally soiled shell eggs at the processing facilities. Salmonellae, including S. Enteritidis, were also isolated from swab samples of henhouses associated with one of the shell-egg processing facilities (11 samples out of 55, 20 %). In the broiler meat production environment, S. Infantis was dominant. Twenty-two of 36 sewage samples (61·1 %) and 16 of 72 samples (22·2 %) taken from 5 rivers contained salmonellae including S. Enteritidis. S. Enteritidis isolates were analysed with pulsed-field gel electrophoresis using enzyme Bln I. Thirty-four isolates from shell-egg processing facilities and henhouses, obtained over several years, had the same pulsed-field profile as isolates obtained from four individual outbreaks that occurred in this location in 1997. One of the clonal lines of S. Enteritidis, among multiple serovars of salmonellae in the environment, was thought to have distributed in reservoirs, laying hens, for several years, and continued to cause outbreaks in this area.

The aim of the study was to define the prevalence of verotoxin-producing Escherichia coli (VTEC) in cattle and pigs in a Hong Kong abattoir. Faecal and carcass samples collected from 986 cattle and 487 pigs from an abattoir were tested for verotoxin (VT) by PCR and cytotoxicity assays. VTEC was isolated from 41·5 and 1·8 % of cattle faecal and carcass samples and from 2·1 and 0·2 % of porcine faecal and carcass samples, respectively. Amongst 409 VTEC isolates from cattle, 9 were serotype O157:H7 and eaeA+. The most prevalent vt genotype among bovine VTEC was vt1+vt2+ (73·8 %) and in porcine VTEC was vt2e+ (30 %). None of the porcine VTEC isolates and 9·3 % of the bovine VTEC isolates was eaeA+. The non-O157 serogroup VTEC isolates carrying eaeA and EHEC-hlyA belonged to serogroups O172, O15, O84, O91, O110 and O121. The local dietary preference for pork or chicken (rather than beef ), the low VTEC carriage in pigs, the rarity of additional virulence factors (eaeA) in VTEC isolated from cattle may explain the apparently low incidence of human diarrhoeal disease associated with VTEC in Hong Kong hitherto. However, the presence of non-O157 VTEC strains carrying the eaeA virulence marker in cattle highlights the fact that sole reliance on sorbitol-MacConkey agar for screening human VTEC isolates may underestimate the human disease burden. The changing dietary habits of the population in Hong Kong reinforce the need for continued vigilance.

Imprecise values arise when bacterial colonies are too numerous to be counted or when no colonies grow at a specific dilution. Our objective was to show the usefulness of multiple imputation in analysing data containing imprecise values. We also indicate that interval censored regression, which is faster computationally in situations where it applies, can be used, providing similar estimates to imputation. We used bacteriological data from a large epidemiological study in daycare centres to illustrate this method and compared it to a standard method which uses single exact values for the imprecise data. The data consisted of numbers of FC on children's and educators' hands, from sandboxes and from playareas. In general, we found that multiple imputation and interval censored regression provided more conservative intervals than the standard method. The discrepancy in the results highlights both the importance of using a method that best captures the uncertainty in the data and how different conclusions might be drawn. This can be crucial for both researchers and those who are involved in formulating and regulating standards for bacteriological contamination.

The saliva-based H. pylori test, HeliSAL™, is insufficiently accurate for use in the clinical setting. However, its ease of use and non-invasiveness make it attractive for population-based studies of the epidemiology of H. pylori. We validated HeliSAL™, and comment here on its usefulness in prevalence surveys. One hundred and ninety-six patients receiving endoscopy at a clinic in New Zealand provided saliva samples for H. pylori assessment, which were compared to CLOtest (Delta West Pty Ltd, Western Australia) as a gold standard measure. Nineteen percent were truly H. pylori positive, 41 % were positive according to HeliSAL™. Test sensitivity was 74 % and specificity was 67 %. While HeliSAL™ is not well suited for the clinical diagnosis of H. pylori infection, it may be useful for large-scale prevalence surveys because, provided it is validated locally, mathematical adjustment can be made for misclassification. Being inexpensive, non-invasive, and easily stored and handled, HeliSAL™ may be a valuable tool for studies of the epidemiology of H. pylori.

Aminoglycoside modifying enzymes (AMEs) are major factors which confer aminoglycoside resistance on bacteria. Distribution of genes encoding seven AMEs was investigated by multiplex PCR for 279 recent clinical isolates of enterococci derived from a university hospital in Japan. The aac(6′)-aph(2″), which is related to high level gentamicin resistance, was detected at higher frequency in Enterococcus faecalis (42·5 %) than in Enterococcus faecium (4·3 %). Almost half of E. faecalis and E. faecium isolates possessed ant(6)-Ia and aph(3′)-IIIa. The profile of AME gene(s) detected most frequently in individual strains of E. faecalis was aac(6′)-aph(2″)+ant(6)-Ia+aph(3′)-IIIa, and isolates with this profile showed high level resistance to both gentamicin and streptomycin. In contrast, AME gene profiles of aac(6′)-Ii+ant(6)-Ia+aph(3′)-IIIa, followed by aac(6′)-Ii alone, were predominant in E. faecium. Only one AME gene profile of ant(6)-Ia+aph(3′)-IIIa was found in Enterococcus avium. The ant(4′)-Ia and ant(9)-Ia, which have been known to be distributed mostly among Staphylococcus aureus strains, were detected in a few enterococcal strains. An AME gene aph(2″)-Ic was not detected in any isolates of the three enterococcal species. These findings indicated a variety of distribution profiles of AME genes among enterococci in our study site.

A survey of the seroprevalence of pertussis antibodies in a representative sample of the population from Catalonia was carried out. Ninety-seven municipalities and 30 schools were randomly selected to recruit the 2126 subjects who participated in the study. A serum sample was obtained from all individuals participating in the study in order to determine levels of pertussis toxin (PT) and filamentous hemagglutinin (FHA) antibodies by ELISA test. Sociodemographic data were collected for all subjects. The prevalence of PT antibodies was 75 % and that of FHA antibodies 89 %. Significant increments were observed with age, both in the prevalence of PT (P < 0·0001) and of FHA (P = 0·018). Of the sociodemographic variables studied, only urban habitat was significantly associated to PT antibodies. The agreement observed among the two types of antibodies studied was weak (κ = 0·264). Routine revaccination with the acellular vaccine in children over 7 years of age, in adolescents and adults seems a reasonable strategy to prevent the appearance of cases of pertussis in the community.

A retrospective ecological study was undertaken to identify social and environmental factors associated with increased incidence of meningococcal disease in university halls of residence. A standardized questionnaire was sent to UK universities and colleges of higher education outside London, for distribution to halls containing at least 50 students. Incidence rate ratios of invasive meningococcal disease were obtained for a range of social and environmental variables. Multi-variable Poisson regression analysis identified 3 factors as having a strong association: a high proportion of first year undergraduate residents (P = 0·0008), decreasing smokiness of the hall bar (P < 0·0001), and opening of hall bar before 1990 (P = 0·0001). The inverse relationship between disease incidence and smokiness of bars was an unexpected finding, and may be due to confounding factors. Universities should continue to promote awareness of meningococcal disease, encourage vaccination of first year students against serogroup C disease, and where appropriate, take measures to reduce overcrowding.

Ciprofloxacin-resistant gonococci have been isolated from patients in the United Kingdom since 1993. Until recently, evidence has suggested that the majority of infections are not endemic but have been acquired abroad. In October 1999, increasing numbers of ciprofloxacin resistant isolates of the non-requiring auxotype were reported in Oldham and Rochdale (Northwest England). These and similar isolates from elsewhere in England and Wales were genetically characterized using a simplified opa-typing method (a non-radioactive PCR–RFLP method targeting the opa family of genes). Of 73 isolates studied, 24 had unique opa-types (10 from infections acquired abroad), whilst the remaining 49 were indistinguishable (none were known to be acquired abroad). This cluster included 31 isolates from Oldham and Rochdale, 16 from elsewhere in the north of England, and 2 from Southern England and South Wales with known epidemiological links to cases from Manchester and Rochdale respectively. This study illustrates the potential for spread of an antibiotic resistant clone of N. gonorrhoeae both locally and nationally and demonstrates that endemic acquisition of ciprofloxacin-resistant gonococci is now a significant problem in the United Kingdom.

The degree of seroprotection against diphtheria in Poland was evaluated by determination of IgG antibodies to Corynebacterium diphtheriae toxin (IgG-DTAb). The study population consisted of 4829 healthy subjects aged from 1 day to 85 years from 7 regions of Poland. Serum samples collected between 1996 and 1998 were assayed for IgG-DTAb antibodies using a toxoid enzyme immunoassay. Neutralization of toxin in Vero cells was performed as a reference method with the WHO standard for human diphtheria antitoxin. The study revealed a lack of seroprotection (IgG-DTAb < 0·1 IU/ml) in 23 % of individuals, basic seroprotection (0·1–1·0 IU/ml) in 64 %, and effective seroprotection (> 1·0 IU/ml) in 13 %. The non-protected group consisted of non-vaccinated children below 2 months of age (10 %), individuals between 2 months and 18 years old (20 %) and greater than 19 years old (70 %). Of the adults, 32 % were seronegative, 63 % had basic seroprotection and only 5 % were fully protected; 43 % of adults between 30 and 64 years, who had not been vaccinated at least during the previous 10 years were not protected against diphtheria. The geometric mean titre (GMT) of IgG-DTAb was 0·25 IU/ml in the total population. Age-related GMTs differed significantly from each other and were higher (0·44 IU/ml) in individuals from 2 months to 18 years old, compared with 0·14 IU/ml and 0·17 IU/ml in children under 2 months and adults, respectively. No significant difference was found in the GMTs of men and women in all age groups. We conclude that the currently used vaccination programme in Poland is highly effective and assures protection against diphtheria in the majority of the population in the 10-year period following the last booster. However, a significant proportion of adults between 30 and 64 years lack protection and this indicates a need for booster immunization for this group.

Two cases of legionellosis occurring 3 years apart were acquired in the same French thermal spa and were apparently due to the same strain of Legionella pneumophila serogroup 1, as shown by genomic macrorestriction analysis. Minor differences between the two isolates were found by random amplification PCR profiling which showed an additional band with one of the isolates. Analysis of 107 L. pneumophila strains isolated from the spa waters by genome macrorestriction failed to identify the infective strain, but a closely related L. pneumophila serogroup 3 strain differing from the clinical isolates by only one band was found. To determine if the clinical L. pneumophila serogroup 1 isolates was better adapted for intracellular multiplication than related serogroup 3 environmental isolates, the growth kinetics of six isolates were determined in co-culture with Acanthamoeba lenticulata. One clinical isolate failed to grow within amoeba, while the other clinical isolate yielded the highest increase in bacterial cell count per amoeba (1200 %) and the environmental isolates gave intermediate values. Genetic analysis of L. pneumophila isolates by DNA macrorestriction does not therefore appear to reflect their growth kinetics within amoeba, and is not sufficiently discriminatory to identify potentially virulent strains.

In April 1999, an outbreak of Pontiac fever occurred at a hotel in Northern Sweden. A retrospective cohort study to find the source and define the extent of the outbreak was carried out among 530 Swedish and Norwegian guests. Twenty-nine epidemiological cases (8 % of 378 responders) aged 21–57 years were identified. Antibodies against Legionella micdadei were detected in 17 of 27 tested cases and 3 other symptomatic persons. Visiting the whirlpool area was identified as the sole risk factor (RR 86; 95 % CI 21–352) and infected cases were confined to visitors to this area over three successive days. The attack rate was 71 % (27/38) and 24 cases (83 %) used the whirlpool. Environmental sampling was negative for Legionella sp. But epidemiological investigation strongly suggests that the whirlpool was the source of the outbreak. The possibility of serious legionella infections underlines the importance of strict maintenance practices to maintain hygiene of whirlpools.

The European Regional Office of WHO has targeted measles for elimination from the region in 2007. Large national, age and sex stratified serological surveys of measles antibody were conducted in seven Western European countries from 1994–8 as part of the European Sero-epidemiology Network. Three patterns were observed in the country-specific measles seroprofiles, ranging from (very) low susceptibility (four countries) to high susceptibility (one country). Susceptibility levels amongst 2–4-year-olds ranged from 2·9 to 29·8 %, in 5–9-year-olds from 2·5 to 25 % and 10–19-year-olds from 2·1 % to 13·9 %. A country's susceptibility profile was highly associated with vaccine coverage for the first dose. First dose coverage ranged from 91 to 97·5 % for low susceptibility countries, 75 to 85 % for intermediate susceptibility countries and 55 % for the high susceptibility country. Only the high susceptibility country still reports epidemic measles. In low susceptibility countries, which have achieved or are very close to measles elimination, the priority will be to maintain high MMR vaccine coverage in all geopolitical units for both vaccine doses. In moderate susceptibility countries there is still some endemic transmission, but also risk of outbreaks as pools of susceptibles accumulate. In the high susceptibility country the priority will be to increase infant vaccine coverage and reduce regional variation in coverage levels.

To predict which patients with current high-risk disease in the community may benefit most from additional preventive or therapeutic measures for influenza, we determined prognostic factors for influenza-associated hospitalization and death in a general practice-based case-control study among this segment of the vaccine target population with high influenza vaccination rates. In 103 general practices followed during the 1996/7 influenza epidemic, cases were either hospitalized or died due to influenza, bronchitis, pneumonia, diabetes, heart failure or myocardial infarction. Age- and gender-matched controls were randomly sampled from the remaining cohort. Information was collected by review of patient records. In total, 119 cases and 196 matched controls were included. Of the cases, 34, 25 and 4 % were hospitalized for acute pulmonary and cardiac disease and diabetes, respectively, and 37 % died. Multivariate conditional logistic regression analysis revealed that presence of chronic obstructive pulmonary disease, heart failure, previous hospitalization, high GP visiting rate and polypharmacy were independent prognostic factors. Several non-modifiable determinants can be used to ensure targeting additional preventive or therapeutic measures at the most vulnerable segment of the vaccine target group.

We investigated the epidemic pattern of chickenpox incidence among 47 prefectures in Japan. There were two peaks in chickenpox incidence in all prefectures. The first peaks appear at almost the same time in a year, while the second peaks occur at different times with relatively different types of size and shape. The feature of the second peak might characterize the epidemic pattern of chickenpox. We first introduced the second peak index, that is, the ratio of the difference between the incidence at the point of the second peak and the minimum incidence between the first and second peaks to the difference between the incidence at the point of the second peak and the minimum incidence in the year. There was a close correlation between the second peak index and the magnitude of variation in temperature within a year corresponding to the difference between the maximum and the minimum of the monthly mean of the highest daily temperature. This is the first article focusing on the close relationship between the second peak of epidemic pattern of chickenpox incidence and the variation of temperature within a year.

Varicella is one of the most common childhood diseases. The course of the disease is usually mild and uncomplicated. In Slovenia, varicella is a notifiable communicable disease which must be reported. Data collected from 1979–98 were analysed. Over the 20-year period the number of varicella cases reported ranged from a low of 11 086 (in 1994) to a maximum of 21 141 (in 1987). During the last 10 years, the highest incidence of varicella was reported in children aged from 12 months to 2 years. In adults over 20, incidence has slightly but steadily increased over the 20 year period. Overall, the number of males with varicella exceeded that of females. The proportion of females was higher only in the 20–30-year age group, probably as a consequence of more frequent and closer contact with infected children by mothers. The highest number of reported cases was during winter and early spring.

This multi-centre, cross-sectional study was designed to reveal the present status of hepatitis B infection markers among Lebanese children, and provide recommendations regarding childhood immunization policies. A total of 841 children, aged between 6 months and 6·5 years, were enrolled from Lebanon's five districts. Their sera were tested for hepatitis B surface antigen and hepatitis B core IgG. The overall prevalence of hepatitis B virus infection markers was 0·8 % with increasing age-specific rates from 0 % at 6 months to 1·3 % at > 5 years. There was no statistically significant association between the presence of hepatitis B markers and family characteristics or risk factors for infection. The highest prevalence rates were among children from Beirut suburbs (2·9 %) and South Lebanon (1·6 %). The risk of horizontal transmission of hepatitis B to uninfected children increased substantially after the age of 2 years. An expanded programme on immunization that integrates hepatitis B vaccine during the first year of life is needed.

This study evaluated the roles of multiple factors in hepatitis C virus (HCV) infection, with emphasis on the modification of various individual characteristics on the risk associated with percutaneous exposure to blood. Serum samples taken from 4869 men in Taiwan within a cohort study were tested for HCV antibody. The overall positive rate of anti-HCV was 1·6 %. In a logistic regression, factors positively associated with anti-HCV positivity were previous blood transfusion (odds ratio [OR] = 7·28; 95 % confidence interval [CI] = 4·26–12·45), a history of surgery (OR = 2·06; 95 % CI = 1·23–3·46), and lower educational levels (OR = 1·94; 95 % CI = 1·14–3·32). The anti-HCV positive rate was significantly lower in hepatitis B surface antigen (HBsAg) carriers than in non-carriers (OR = 0·60; 95 % CI = 0·37–0·95). Ageing, lower educational levels, O blood group, and Taiwanese ethnicity enhanced the likelihood of HCV infection through blood transfusion/surgery, whereas HBsAg status, cigarette smoking, and habitual alcohol drinking reduced it.

In 1996, serological responses to two Cryptosporidium antigens were determined for 200 Las Vegas (LV), Nevada, and 200 Albuquerque, New Mexico, blood donors to evaluate associations between endemic infections, water exposures, and other risk factors. LV uses chlorinated filtered drinking water from Lake Mead while Albuquerque uses chlorinated ground water. The intensity of serological response to both markers was higher for older donors (P < 0·05), donors who washed food with bottled water (P < 0·05) and donors from LV (P < 0·05). A decreased serological response was not associated with bottled water consumption, nor was an increased response associated with self-reported cryptosporidiosis-like illness or residence in LV at the time of a cryptosporidiosis outbreak 2 years earlier. Although these findings suggest the serological response may be associated with type of tap water and certain foods, additional research is needed to clarify the role of both food and drinking water in endemic Cryptosporidium infection.

The natural habitat of Paracoccidioides brasiliensis, agent of paracoccidioidomycosis (PCM), remains unknown. This study is aimed at establishing associations between the ecological variables present in all Colombian municipalities and the incidence of PCM. Records of 940 patients were studied and several ecological variables analysed, as well as their association to amount of patients per total rural population in each municipality, determined through a multivariate analysis. All 940 patients came from 216 municipalities (20·3 %), out of which, 93 were birthplace and place of long-term residence for 121 patients. The Incidence Rate Ratio (IRR) was determined for these 93 municipalities. The following variables fitted the model: altitude from 1000 to 1499 metres above sea level (IRR = 6·37), rainfall from 2000 to 2999 mm (IRR = 2·15), presence of humid forests (Holdridge) (IRR = 1·79) and coffee (IRR = 1·95), tobacco (IRR = 3·59) crops. These results indicate that these municipalities constitute reservareas for P. brasiliensis (Borelli).

Aedes aegypti female mosquitoes are capable of the mechanical transmission of lumpy skin disease virus (LSDV) from infected to susceptible cattle. Mosquitoes that had fed upon lesions of LSDV-infected cattle were able to transmit virus to susceptible cattle over a period of 2–6 days post-infective feeding. Virus was isolated from the recipient animals in 5 out of 7 cases. The clinical disease recorded in the animals exposed to infected mosquitoes was generally of a mild nature, with only one case being moderate. LSDV has long been suspected to be insect transmitted, but these findings are the first to demonstrate this unequivocally, and they suggest that mosquito species are competent vectors.