Rotavirus (RV) infections affect young children, but can also occur in adults. We sought to identify risk factors for RV infections in adults aged ⩾18 years in Denmark, and to describe illness and genotyping characteristics. From March 2005 to February 2009, we recruited consecutive cases of laboratory-confirmed RV infection and compared them with healthy controls matched by age, gender and municipality of residence. We collected information on illness characteristics and exposures using postal questionnaires. We calculated univariable and multivariable matched odds ratios (mOR) with conditional logistic regression. The study comprised 65 cases and 246 controls. Illness exceeded 10 days in 31% of cases; 22% were hospitalized. Cases were more likely than controls to suffer serious underlying health conditions [mOR 5·6, 95% confidence interval (CI) 1·7–18], and to report having had close contact with persons with gastrointestinal symptoms (mOR 9·4, 95% CI 3·6–24), in particular young children aged <3 years and adults aged >18 years. Close contact with young children or adults with gastrointestinal symptoms is the main risk factor for RV infection in adults in Denmark. RV vaccination assessments should consider that RV vaccination in children may indirectly reduce the burden of disease in adults.

The most widely used indicator of the sanitary quality of recreational waters is the coliform group of bacteria. Present techniques of coliform enumeration are imprecise, and this fact is too often overlooked in routine water quality surveys as well as in research efforts seeking quantitative relationships between coliform density and the health effects of recreational waters. To illustrate this point, three years of data gathered by the New York City Department of Health as part of their routine beach water sampling programme were re-analysed, taking the limited precision of each coliform estimate into account. Re-analysis showed 56·6% of the data were not significantly different (P > 0·05) from the standard being used. This large percentage of the data was of little value in determining the acceptability of the waters being sampled relative to the standard being used and thus represented a substantial waste of time and expense. Of the remaining data, half indicated acceptable water quality and half indicated unacceptable water quality relative to the standard. These three years of data, therefore, gave little information on the acceptability of the water quality at this location with respect to the standard being used. The data further suggest significant differences in coliform density within sample dates. It is recommended that in future water quality surveys, or in studies of the health effects of recreational waters as related to coliform density, emphasis should shift from maximizing the number of sample dates to maximizing the number of replicate determinations made per sample date.

Epidemiological analysis of Klebsiella strains from nosocomial infections needs a simple, stable and reproducible technique of typing. We have evaluated three bacteriocin typing methods for Kiebsiella spp. by means of 15 bacteriocin-producing strains, with special reference to stability and reproducibility.

With the three methods indicator strains and clinical strains were retyped on different days under constant test procedures. Stability of bacteriocins was tested by titration immediately after preparation and after 4 weeks of storage at –70°C. Thereafter, reproducibility of typing was tested by means of these freshly prepared bacteriocin lysates and of portions of the same lysates stored at –70 °C. A moderate reproducibility was obtained with one method after two typing experi ments: 79.2% and 61.3% for indicator strains and clinical strains respectively. The other two methods gave a much lower reproducibility of 38 .5% and 32.5 % for indicator strains and of 11.1% and 25.5% for clinical strains after two experiments.

The reproducibility decreased after retyping three, four or five times. These methods are simple to perform but their usefulness for epidemiological studies is doubtful. Possible causes of the lack of reproducibility of the methods are discussed.

This study aims to evaluate the impact of non-pharmaceutical interventions (NPIs) on the prevalence of respiratory pathogens among hospitalised children with acute respiratory infections (ARIs) in Suzhou. Children with ARIs admitted to the Children’s Hospital of Soochow University between 1 September 2021 and 31 December 2022 and subjected to 13 respiratory pathogen multiplex PCR assays were included in the study. We retrospectively collected demographic details, results of respiratory pathogen panel tests, and discharge diagnostic information of the participants, and described the age and seasonal distribution of respiratory pathogens and risk factors for developing pneumonia. A total of 10,396 children <16 years of age, including 5,905 males and 4,491 females, were part of the study. The positive rates of the 11 respiratory pathogen assays were 23.3% (human rhinovirus (HRV)), 15.9% (human respiratory syncytial virus (HRSV)), 10.5% (human metapneumovirus (HMPV)), 10.3% (human parainfluenza virus (HPIV)), 8.6% (mycoplasma pneumoniae (MP)), 5.8% (Boca), 3.5% (influenza A (InfA)), 2.9% (influenza B (InfB)), 2.7% (human coronavirus (HCOV)), 2.0% (adenovirus (ADV)), and 0.5% (Ch), respectively. Bocavirus and HPIV detection peaked during the period from September to November (autumn), and MP and HMPV peaked in the months of November and December. The peak of InfA detection was found to be in summer (July and August), whereas the InfB peak was observed to be in winter (December, January, and February). HRSV and HRV predominated in the <3 years age group. HRV and HMPV were common in the 3–6 years group, whereas MP was predominant in the ≥6 years group. MP (odds ratio (OR): 70.068, 95%CI: 32.665–150.298, P < 0.01), HMPV (OR: 6.493, 95%CI: 4.802–8.780, P < 0.01), Boca (OR: 3.300, 95%CI: 2.186–4.980, P < 0.01), and HRSV (OR: 2.649, 95%CI: 2.089–3.358, P < 0.01) infections were more likely to develop into pneumonia than the other pathogens. With the use of NPIs, HRV was the most common pathogen in children with ARIs, and MP was more likely to progress to pneumonia than other pathogens.

Although the impact of diarrhoeal disease on paediatric health in Nigeria has decreased in recent years, it remains an important cause of morbidity and mortality in children under 5 years. Rotavirus is recognised as an important aetiological agent, but information on the contribution of intestinal protozoa to watery diarrhoea in this age group in Nigeria is scarce. In this cross-sectional study, faecal samples from children admitted to healthcare centres in Abakaliki, Nigeria with acute watery diarrhoea (N = 199) and faecal samples from age-matched controls (N = 37) were examined for Cryptosporidium and Giardia using immunofluorescent antibody testing and molecular methods. Cryptosporidium was identified in 13 case samples (6.5%) and no control samples. For three samples, molecular characterisation indicated C. hominis, GP60 subtypes IaA30R3, IaA14R3 and IdA11. Giardia was not detected in any samples. This contrast in prevalence between the two intestinal protozoa may reflect their variable epidemiologies and probably differing routes of infection. Given that these two parasitic infections are often bracketed together, it is key to realise that they not only have differing clinical spectra but also that the importance of each parasite is not the same in different age groups and/or settings.

Pneumonia leads to considerable morbidity and mortality in nursing home residents with dementia. We assessed pneumonia incidence based on data from three different studies: (1) real-time national surveillance of healthcare-associated infections in nursing home residents in 2009–2015; (2) a randomized controlled trial in 2012–2015 to assess effects of a practical guideline in nursing home residents with dementia and pneumonia; and (3) a study in 2007–2010 to assess quality of dying in newly admitted nursing home residents with dementia. In national surveillance data, pneumonia incidence was calculated separately for psychogeriatric and somatic beds, as a proxy for residents with and without dementia. Weekly pneumonia incidence was significantly lower per 1000 psychogeriatric beds (3·9; 95% confidence interval (CI) 3·2–4·6) compared with 1000 somatic beds (5·7; 95% CI 5·1–6·3). Annual incidence per 1000 psychogeriatric beds was similar in national surveillance (range 78·9–117·1) and the trial (range 71·0–94·3), and significantly higher in newly admitted dementia residents (range 267·3–363·2). The incidence was highest during the first months after admission when compared with residents with longer stay. In conclusion, follow-up of pneumonia in newly admitted dementia residents may result in higher incidence, possibly due to higher risk in this population.

Research in epidemiology may be concerned with assessing risk factors for complex health issues described by several variables. Moreover, epidemiological data are usually organized in several blocks of variables, consisting of a block of variables to be explained and a large number of explanatory variables organized in meaningful blocks. Usual statistical procedures such as generalized linear models do not allow the explanation of a multivariate outcome, such as a complex disease described by several variables, with a single model. Moreover, it is not easy to take account of the organization of explanatory variables into blocks. Here we propose an innovative method in the multiblock modelling framework, called multiblock redundancy analysis, which is designed to handle most specificities of complex epidemiological data. Overall indices and graphical displays associated with different interpretation levels are proposed. The interest and relevance of multiblock redundancy analysis is illustrated using a dataset pertaining to veterinary epidemiology.

Notification of infectious disease is essential for prompt public health action and epidemiological analysis. The aim of this study was to compare national hospitalization data to national notification data in order to assess if there was significant under-reporting of hospitalized notifiable infectious diseases in recent years in Ireland. All in-patient discharges from public hospitals in the Republic of Ireland from 2006 to 2011 with a principal diagnosis of a notifiable disease were compared with national notification data. It was found that only a potential 1·8% of extra notifications could have arisen due to these hospitalization events and would represent a tenfold reduction on a previous estimate of under-reporting in the Irish context. Viral meningitis, viral encephalitis, bacterial meningitis not otherwise specified and malaria were the most common diseases for which there were more hospitalizations than notifications reported. The results of this study support the conclusion that the reduction in under-reporting can mainly be accounted for by the introduction of laboratories as notifiers in conjunction with the roll out of the Computerized Infectious Disease Reporting system (CIDR). However, for the diseases highlighted, the notification data underestimates the true burden of disease and this has implications for understanding the epidemiology of these diseases.

1. The paper represents an attempt to estimate the error of the standard 10 ml. Haldane gas analysis apparatus under routine conditions of use.

2. The ultimate error of the instrument under optimum conditions has been obtained from duplicate mercury calibrations of the same instrument and corresponds to s.d. = 0·013% gas. A significant day-to-day variation in calibration was found.

3. The accuracy in routine use has been determined by replicate estimations of CO2 and O2 in air and from estimation of CO2 in designed experiments. The data show an error corresponding to s.d. = 0·027 to 0·13%. This is far larger than that described by Haldane.

4. Examination of the distribution of terminal digits in burette readings shows that the smallest scale division is in fact not being divided into ten parts by the worker. Preference for certain digits varies with the individual, with time, and with the accuracy required.

5. There is a marked tendency for a worker to obtain an ‘expected result’, whether this is derived from a previous estimation of the same sample or from knowledge of the expected result; such bias tends to reduce the apparent error of estimation. Bias of replication—‘prejudice error’—may play a part in many forms of measurement.

6. The results and conclusions are discussed in relation to other published data on errors of measurement in general.

1. A series of 110 patients with staphylococcal infections has been investigated. From 43 patients a penicillin-resistant staphylococcus was isolated: in cultures from 38 patients all staphylococcal colonies tested were penicillin resistant and in five both sensitive and resistant strains were isolated. Seven patients yielded a streptomycin-resistant staphylococcus.

2. Of the 84 strains of staphylococci which could be phage typed, 33 belonged to the group of phages 6/7/47 and 32 were of type 52 A. Of the 32 typable penicillin- resistant strains 18 belonged to the group of phages 6/7/47, and 13 were type 52 A.

3. Of the 115 strains isolated 110 were α-lysinogenic.

4. These results are compared with those found a year previously and the significant changes are discussed.

Foodborne and waterborne gastrointestinal infections and their associated outbreaks are preventable, yet still result in significant morbidity, mortality and revenue loss. Many enteric infections demonstrate seasonality, or annual systematic periodic fluctuations in incidence, associated with climatic and environmental factors. Public health professionals use statistical methods and time series models to describe, compare, explain and predict seasonal patterns. However, descriptions and estimates of seasonal features, such as peak timing, depend on how researchers define seasonality for research purposes and how they apply time series methods. In this review, we outline the advantages and limitations of common methods for estimating seasonal peak timing. We provide recommendations improving reporting requirements for disease surveillance systems. Greater attention to how seasonality is defined, modelled, interpreted and reported is necessary to promote reproducible research and strengthen proactive and targeted public health policies, intervention strategies and preparedness plans to dampen the intensity and impacts of seasonal illnesses.

The infectious fevers have, during the last fifty years, been the subject of much epidemiological research, and have thus been made to yield up secrets which have materially affected the whole outlook of preventive medicine. But there yet remains for exploration a vast adjacent territory, that of minor coccal infections of the skin. However, whereas the former, being clearly defined clinically and in many cases subject to compulsory notification, lend themselves well to investigations of this sort, Impetigo, as a type of minor coccal dermatitis, surrounds itself with dificulties. For not only does it vary very much in its appearances by the time it is first seen but it is often of so little severity that it does not come under the observation of a physician at all, so that the influence of missed cases, always an important factor to be reckoned with in the study of epidemics, may assume such proportions as to give quite an erroneous impression of the total incidence of the disease. Consequently the epidemic aspects of impetigo have as yet received very little attention.

We identified an increase in the number of cases of Salmonella Typhimurium phage type 197 in New South Wales in February 2005. Cases were predominantly of Lebanese descent. To identify risk factors for illness, we conducted an unmatched case-control study including 12 cases and 21 controls. Eight of 12 cases (67%) and no controls reported eating lambs' liver (OR incalculable, P<0·05), and seven of nine cases (78%) and one of 21 controls (5%) reported eating fresh fish (OR 70·0, P<0·05). Among participants who did not eat liver, there was a strong association between eating fish and illness (OR 60·0, P<0·05). The fish was from divergent sources. Five cases had bought the liver from two different butcher's shops, which obtained the lambs' liver from a single abattoir. Consumption of liver is a risk for salmonellosis. Traditional dishes may place some ethnic groups at increased risk of foodborne disease.

A colony count performed by spreading a known volume of suspension on the surface of a plate possesses certain advantages over other methods, of which the chief is ease of counting.

The distribution of counts of several samples of the same suspension on medium of the same age and batch is as expected on statistical grounds.

Different batches and ages of blood plates may give substantially the same count but this is not true for Leifson's and Wilson & Blair's media.

A diluting fluid, which is satisfactory if blood agar is the plating medium, may not necessarily be so if special media are to be used.

The impact of hepatitis B vaccination in men having sex with men in Amsterdam has been marginal until now, possibly because of increases in sexual risk behaviour counterbalancing the effect of vaccination. A mathematical model is used to describe the hepatitis B epidemic. The model shows that, with the current vaccination coverage, the decrease in incidence is small in the beginning. However, the number of infections prevented per vaccine administered rises over time. Nevertheless, increased risk behaviour reduces the benefit of vaccination. Targeting high-risk men is more successful in reducing and containing the epidemic than targeting low-risk men. In conclusion, the vaccination campaign is effective and should be intensified. High-risk men should be targeted for vaccination and for risk reduction.

A study was conducted to characterize the risk of Plasmodium vivax infection in the Lacandon forest, southern Mexico. Blood samples and questionnaire data were collected in 1992. Malaria cases (n = 137) were identified by the presence of symptoms and a positive thick blood smear. The control group included individuals with negative antibody titres and no history of malaria (n = 4994). From 7628 individuals studied, 1006 had anti-P. vivax antibodies. Seroprevalence increased with age. Risk factors associated with infection included: place of birth outside the village of residence (odds ratio, OR 11·67; 95% CI 5·21–26·11); no use of medical services (OR 4·69, 95% CI 3·01–7·29), never using bed-nets (OR 3·98, 95% CI 1·23–12·86) and poor knowledge of malaria transmission, prevention and treatment (OR 2·30, 95% CI 1·30–4·07). Health education represents the best recommendation for controlling the disease in the area.

Public health interest in norovirus (NoV) has increased in recent years following improved diagnostics, global burden estimates and the development of NoV vaccine candidates. This study aimed to describe the detection rate, clinical characteristics and environmental features associated with NoV detection in hospitalized children <5 years with diarrhoea in South Africa (SA). Between 2009 and 2013, prospective diarrhoeal surveillance was conducted at four sites in SA. Stool specimens were collected and screened for NoVs and other enteric pathogens using molecular and serological assays. Epidemiological and clinical data were compared in patients with or without detection of NoV. The study detected NoV in 15% (452/3103) of hospitalized children <5 years with diarrhoea with the majority of disease in children <2 years (92%; 417/452). NoV-positive children were more likely to present with diarrhoea and vomiting (odds ratio (OR) 1·3; 95% confidence interval (CI) 1·1–1·7; P = 0·011) with none-to-mild dehydration (adjusted OR 0·5; 95% CI 0·3–0·7) compared with NoV-negative children. Amongst children testing NoV positive, HIV-infected children were more likely to have prolonged hospitalization and increased mortality compared with HIV-uninfected children. Continued surveillance will be important to consider the epidemic trends and estimate the burden and risk of NoV infection in SA.

Infection with hepatitis A virus (HAV) in patient with chronic liver disease (CLD; due to hepatitis B or hepatitis C) may cause severe disease and fulminant liver failure. This study aimed to determine the seroprevalence of HAV antibodies in patients infected with HCV or HBV in Iran (Jahrom city). A total of 159 patients with underlying CLD were recruited between September 2012 and February 2013. Serum samples were collected from each patient and tested for anti-HAV using enzyme-linked immunosorbent assay (ELISA). The overall seroprevalence of total anti-HAV was 79·2%. Patients aged 20–30 years had the lowest (28·3%) anti-HAV seropositivity and those aged >50 years had the highest (95%) seropositivity. The overall prevalence of anti-HAV in patients with chronic HCV and HBV infection was 93·7% and 77·1%, respectively. The anti-HAV seropositivity in liver cirrhosis patients was 100% compared to CLD patients. Because of low HAV immunity in younger CLD patients, vaccination against HAV should be considered.

Chlamydia pneumoniae infection is said to be associated with obesity. We studied the association between C. pneumoniae infection and inflammation and increased BMI in 891 Finnish military recruits. IgG seropositivity in arrival and departure serum samples during 6–12 months of military service was considered as persistence of antibodies and a possible indication of chronic infection. Persistently high C-reactive protein (CRP) level (elevated on arrival and departure) (OR 2·2, 95% CI 1·3–3·9), and persistent C. pneumoniae antibodies (OR 2·1, 95% CI 1·5–2·8) were significant risk factors for overweight (BMI ⩾25 kg/m2). In addition, those who had persistent antibodies and persistently elevated CRP levels, or those who had either of them, had a significantly higher BMI (kg/m2) compared to those who had neither of them (25·8 vs. 24·6 vs. 23·5, respectively; P<0·001). These results provide new information about the association between possible chronic C. pneumoniae infection and obesity in young men.

We describe a method of working on publicly available data to estimate disease prevalence in small geographic areas using Helicobacter pylori as a model infection. Using data from the Third National Health and Nutrition Examination Survey, risk parameters for H. pylori infection were obtained by logistic regression and validated by predicting 737·5 infections in an independent cohort with 736 observed infections. The prevalence of H. pylori infection in the San Francisco Bay Area was estimated with the probabilities obtained from a predictive logistic model, using risk parameters with individual-level 1990 U.S. Census data as input. Predicted H. pylori prevalence was also compared to gastric cancer incidence obtained from the Northern California Cancer Center and showed a positive correlation with gastric cancer incidence (P<0·001, R2=0·87), and no statistically significant association with other malignancies. By exclusively using publicly available data, these methods may be applied to selected conditions with strong demographic predictors.