This observational study aims to investigate the microbiological quality of commercially prepared lightly cooked foods with a major component of food of animal origin and collected as would be served to a consumer. A total of 356 samples were collected from catering (92%), retail (7%) or producers (1%) and all were independent of known incidents of foodborne illness. Using standard methods, all samples were tested for: the presence of Campylobacter spp. and Salmonella spp. and enumerated for levels of, Bacillus spp. including B. cereus, Clostridium perfringens, Listeria spp. including L. monocytogenes, Staphylococcus aureus, Escherichia coli, Enterobacteriacea and aerobic colony count (ACC). Results were interpreted as unsatisfactory, borderline or satisfactory according to the Health Protection Agency guidelines for assessing the microbiological safety of ready-to-eat foods placed on the market. Amongst all samples, 70% were classified as satisfactory, 18% were borderline and 12% were of unsatisfactory microbiological quality. Amongst the unsatisfactory samples, six (2%) were potentially injurious to health due to the presence of: Salmonella spp. (one duck breast); Campylobacter spp. (two duck breast and one chicken liver pâté); L. monocytogenes at 4·3 × 103 cfu (colony-forming units)/g (one duck confit with foie gras ballotin) and C. perfringens at 2·5 × 105 cfu/g (one chicken liver pâté). The remaining unsatisfactory samples were due to high levels of indicator E. coli, Enterobacteriaceae or ACC.

A third nationally representative serosurvey was performed to study the changes in Toxoplasma gondii (T. gondii) seroprevalence in the Netherlands over a 20-year time span and to identify and confirm risk factors for acquired toxoplasmosis. This cross-sectional study (conducted in 2016/2017) was designed similarly to the previous two studies (1995/1996 and 2006/2007) and included a questionnaire and serum sampling among Dutch residents. Factors associated with seropositivity for T. gondii were determined using multivariable analysis of the questionnaire-derived data. The earlier observed decrease in T. gondii seroprevalence between 1995/1996 and 2006/2007 (from 40.5% to 26.0%) did not continue into 2016/2017 (29.9%). Similarly to the previous studies, the seroprevalence increased with age and varied among regions. In all studies, higher T. gondii seropositivity was associated with increasing age, lower educational level, not living in the Southeast, and eating raw or semi-cooked pork. The incidence of congenital toxoplasmosis was estimated at 1.3/1000 (95% CI 0.9–1.8) live-born children in 2017. As the seroprevalence of T. gondii in the Netherlands did not decrease over the last decade, an increase in public health awareness is needed and prevention measures may need to be taken to achieve a further reduction in T. gondii infections in the Netherlands.

We reviewed key attributes (flexibility, data quality and timeliness) of Australia's National Notifiable Diseases Surveillance System (NNDSS) over its first 21 years. Cases notified to NNDSS from 1991 to 2011 were examined by jurisdiction (six states and two territories) and sub-period to describe changes in the number of notifiable diseases, proportion of cases diagnosed using PCR tests, data quality (focusing on data completeness), and notification delays. The number of notifiable diseases increased from 37 to 65. The proportion of cases diagnosed by PCR increased from 1% (1991–1997) to 49% (2005–2011). Indigenous status was complete for only 44% notifications (jurisdictional range 19–87%). Vaccination status was complete for 62% (jurisdictional range 32–100%) and country of acquisition for 24% of relevant cases. Data completeness improved over the study period with the exception of onset date. Median time to notification was 8 days (interquartile range 4–17 days, jurisdictional range 5–15 days); this decreased from 11 days (1991–1997) to 5 days (2005–2011). NNDSS expanded during the study period. Data completeness and timeliness improved, likely related to mandatory laboratory reporting and electronic data transfer. A nationally integrated electronic surveillance system, including electronic laboratory reporting, would further improve infectious disease surveillance in Australia.

Accurate methods for determining the duration of HIV infection at the individual level are valuable in many settings, including many critical research studies and in clinical practice (especially for acute infection). Since first published in 2003, the ‘Fiebig staging system’ has been used as the primary way of classifying early HIV infection into five sequential stages based on HIV test result patterns in newly diagnosed individuals. However, Fiebig stages can only be assigned to individuals who produce both a negative and a positive test result on the same day, on specific pairs of tests of varying ‘sensitivity’. Further, in the past 16 years HIV-testing technology has evolved substantially, and three of the five key assays used to define Fiebig stages are no longer widely used. To address these limitations, we developed an improved and more general framework for estimating the duration of HIV infection by interpreting any combination of diagnostic test results, whether obtained on single or multiple days, into an estimated date of detectable infection, or EDDI. A key advantage of the EDDI method over Fiebig staging is that it allows for the generation of a point estimate, as well as an associated credibility interval for the date of first detectable infection, for any person who has at least one positive and one negative HIV test of any kind. The tests do not have to be run on the same day; they do not have to be run during the acute phase of infection and the method does not rely on any special pairing of tests to define ‘stages’ of infection. The size of the interval surrounding the EDDI (and therefore the precision of the estimate itself) depends largely on the length of time between negative and positive tests. The EDDI approach is also flexible, seamlessly incorporating any assay for which there is a reasonable diagnostic delay estimate. An open-source, free online tool includes a user-updatable curated database of published diagnostic delays. HIV diagnostics have evolved tremendously since that original publication more than 15 years ago, and it is time to similarly evolve the methods used to estimate timing of infection. The EDDI method is a flexible and rigorous way to estimate the timing of HIV infection in a continuously evolving diagnostic landscape.

An outbreak of food-poisoning is described in which the B. morbificans bovis (Basenau) was the causal agent. The position of this type in the Salmonella group as classified by Bruce White has been confirmed by analysis of the antigenic properties and agglutination reactions (including absorption of agglutinin) of the strains isolated in the outbreak.

An analysis of the meteorological conditions showed that the first outbreaks of myxomatosis in S.E.England in 1953 could have resulted from wind carriage of insects infected with myxoma virus from northern France. South-easterly winds on the night 11–12 August would have carried the insects 120–160 km from the Départements of Nord, Pas de Calais and Somme across the English Channel to near Edenbridge, Kent. The flight would have taken 6·5–8·5 h at wind speeds of 15–22 km h−1. On the night 11–12 August, temperatures increased with height (inversion) up to 500 m; at ground level temperature was around 19 °C and at 500 m was 25 °C. Insects would have travelled up to the top of the inversion arriving on 12 August as the inversion declined. Two or possibly three generations of infection would have taken place before the disease was seen around the middle of September 1953. The most likely insect was the mosquito Anopheles atroparvus which breeds along the coastal marshes of England and northern France and which has been shown experimentally and in the field to transmit myxoma virus mechanically.

A total of 21 rubella seronegative children vaccinated subcutaneously with Wistar RA 27/3 strain live attenuated rubella vaccine in a family study of vaccine virus transmissibility were reviewed after 6 years. Haemagglutinating inhibiting (HAI) antibody titres of sera collected 46 days, 2 years and 6 years after vaccination were compared. Antibody titres in the vaccinated subjects were not significantly influenced by time, infection in susceptible siblings or revaccination.

Kittens with maternal antibodies to myxoma virus, the offspring of rabbits which had recovered from myxomatosis, were exposed to fleas contaminated with myxoma virus and/or contact with infected rabbits from birth. All kittens died or became infected before 8 weeks of age. When compared with adult animals similarly infected the kittens showed no advantage in terms of survival time or recovery rate attributable to maternal antibodies. Flea transmission of virus was found more effective than contact transmissions.

The aim of our study was to determine the distribution of hepatitis B virus (HBV) genotypes and subgenotypes in ethnic minorities in Yunnan province to provide evidence supporting the theoretical basis for hepatitis B prevention and control. We obtained serum samples and demographic data from 765 individuals reported by Yunnan province who had either acute or chronic HBV infection and were from one of 20 ethnic minority populations: Achang, Bai, Brown, Tibetan, Dai, Deang, Dulong, Hani, Hui, Jingpo, Lahu, Yi, Lisu Miao, Naxi, Nu, Pumi, Wa, Yao, or Zhuang people. We sequenced the HBV DNA and determined the genotypes and subgenotypes of the isolated HBVs. We mapped the genotype and subgenotype distribution by ethnic minority population and conducted descriptive analyses. There were four genotypes among the 20 ethnic groups: genotype B (21.3% of samples), C (76.6%), D (1.8%) and I (0.3%). The most common subgenotype was C1. There were no genotype differences by gender (P = 0.954) or age (P = 0.274), but there were differences by region (P < 0.001). There were differences in genotype distribution (P < 0.001) and subgenotype distribution (P = 0.011) by ethnic group. Genotype D was most prominent in Tibet and most HBV isolates were C/D recombinant viruses. The only two genotype I virus isolates were in Zhuang people. Susceptibility and geographic patterns may influence HBV prevalence in different ethnic populations, but additional research is needed for such a determination.

A total of 160 consecutive isolates of Neisseria gonorrhoeae was collected over a 3-month period. They were tested for their susceptibility to penicillin, erythromycin and spectinomycin and the auxotype and the serotype determined. We have evaluated two sampling methods, the collection of every fifth isolate and the first 20 isolates (10 male and 10 female) each month, to determine whether either is representative of the total population. There was no significant difference between either method of sampling and the total for detecting the predominant auxotypes and serovars or the distributions in antibiotic susceptibility. It is possible to monitor major changes in a gonococcal population, particularly susceptibility to antibiotics, using a sample of the total population.

Considerable difference of opinion has existed as to whether the incidence of cancer is at all affected by the habits of life of different classes of the community. There is of course no doubt that in certain occupations particular forms of malignant disease are exceptionally prevalent, the case of chimney sweeps being notorious; but the more general question as to the incidence on large groups of occupations has not been so definitely determined. The present research was suggested by the apparently contradictory results obtained by Heron from his study of London statistics, and by Maynard from an analysis of United States data.

1. The susceptibility of sheep to infection with Langat virus has been studied. No viraemia or symptoms were detected in sheep inoculated either subcutaneously or intracerebrally.

2. Only those sheep inoculated intracerebrally with 106·0–108·0 mouse IC LD 50 of virus developed significant quantities of neutralizing antibody.

3. Two-thirds of sheep vaccinated with varying doses of Langat virus withstood subcutaneous challenge of louping-ill virus followed by intracerebral starch. All the intracerebrally vaccinated sheep survived this form of challenge but no sheep, whether vaccinated subcutaneously or intracerebrally, withstood intracerebral challenge of louping ill.

4. In a field trial, three of ten hoggs vaccinated with Langat virus and exposed to natural louping ill infection at Camlarg and Dalcairnie died of the disease compared with all eight of the non-vaccinated hoggs. At Knockgray, there was no louping ill infection, but 93% of the hoggs from this hirsel developed louping ill antibody after transfer to Camlarg.

5. Monkeys infected intracerebrally, subcutaneously or orally with Langat virus showed a low titre viraemia without clinical symptoms or histological changes in the brain and developed high titres of antibody. Vaccinated monkeys challenged with either Central European tick-borne encephalitis or Kyasanur Forest disease viruses remained healthy compared with control monkeys which showed evidence of disease.

A method of controlling outbreaks of streptococcal infection of the upper respiratory tract in communities such as boarding schools is described.

It is suggested that, in a search for carriers, nose and mouth swabs should be taken in place of the customary nose and throat swabs. These swabs will detect those who are dispersing streptococci into the environment, as distinct from the carriers who are not dispersers. It is essential that infections of the skin and ears should also be looked for.

It is recommended that all dispersers, whether nose or mouth positive, should receive sulphanilamide insufflation in both nostrils twice daily for a week, or longer if necessary, without exclusion from school. In addition, penicillin lozenges for 2 days may be recommended for the mouth positives only.

The history is considered to be an important factor in deciding the extent of the initial investigation, and examples are given to illustrate this. When mass swabbing is considered necessary, it is highly desirable that the whole community should be swabbed at the same time, as early as possible in the outbreak. It is also desirable that bacteriological follow-up should be available to check that control has been effected.

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 terms of the rate of positive diagnoses the indirect fluorescent antibody (FA) test was rather more effective than iodine for demonstrating trachoma (TRIC) inclusions in conjunctival scrapings, but the degree of advantage was not statistically significant. In duplicate scrapings stained at random by one or the other method, FA staining yielded the higher inclusion count significantly more often than did iodine. Some inclusions that failed to stain with FA were found on subsequent staining with Giemsa. A method is described for improving the post-FA Giemsa staining of conjunctival smears stored at subzero temperatures. Given adequate facilities, the FA stain is preferable to iodine for demonstrating TRIC inclusions in the conjunctiva; but the iodine method, properly used, holds advantages for field use.

DNA- fingerprints (Hind III) of Streptococcus uberis field isolates from New York State and Europe showed substantial homogeneity, but were different to those of the type strain of the newly proposed psychrophilic species S. parauberis. S. uberis strains had major SDS-heat extracted antigens of molecular masses (Mr) < 14, 40–41, 42–43, 59–61, 80–86 and 118–122 kDa following immunoblotting with rabbit hyperimmune sera. Bovine sera and milk reacted with the 40–41 and 118–122 kDa antigens. Variations in the Mr of particular bands were too unevenly distributed to permit formation of subgroups. Although cross reactive, the sizes of the antigens of S. parauberis strain NCDO 2020 were substantially different to those of S. uberis, the most prominent antigen having a Mr of 50 kDa. The antigenic and genetic data therefore strongly support the introduction of S. parauberis as a distinct species. S. uberis strains reacted with antiserum to Lancefield groups B, E, G and P, their grouping reactions showing no correlation with DNA and immunoblot fingerprints. Lancefield grouping of S. uberis therefore appears to have little value in identification.

Nasal carriage of Staphylococcus aureus was studied in a cohort of infants born to the residents of two towns in South Wales. The children were followed up to the age of 5 years, nasal swabs being taken annually after a more detailed survey during the first year. The carriage-rate of S. aureus reached a minimum of 10–15% at one year and then rose steadily to 41% at five years. From the age of two years about 90% of the organisms isolated were resistant to penicillin. There was a marked tendency for children to carry the same strains from year to year, but carriage during the first year of life did not predict carriage at the age of five.

An epidemiological study of Sonne dysentery in Dundee during the years 1971–6 was made by examining, in respect of 1420 isolates of Shigella sonnei, the discriminating power of colicine typing, antibiogram testing, biotyping and resistotyping and the stability of the markers they provided.

Colicine typing identified nine colicine types, including four not previously described. However, because types 4 and 4 var., determined by col Ib, and type U, producing no colicines, accounted for 96 % of the isolates, discrimination with colicine typing was poor. In antibiotic sensitivity tests, 13 different antibiogram patterns were noted. Less than 1 % of the isolates were sensitive to all of the eight antibiotics tested; most were multiply drug-resistant. Resistance to kanamycin, neomycin and paromomycin (KNP) was apparently due to a single resistance determinant, widely distributed in a majority (53%) of the isolates. When definitive times were chosen for reading each biotyping test, only maltose and rhamnose of the 13 ‘sugars’ tested differentiated isolates into prompt- and late-fermenting types. Though the ability to ferment rhamnose was a stable property, it discriminated only 1·5% of the minority, late-fermenting type. Resistotyping with six chemicals discriminated eight epidemiologically valid resistotypes, including three new types. However, 93 % of the isolates belonged to only three resistotypes.

Analysis of the data for isolates from 286 epidemiologically distinct episodes showed that the variability of colicine and antibiogram characters, found among isolates within, respectively, 40 and 28 % of the episodes, was generally associated with loss or gain of a plasmid (‘col Ib-KNP’) which determined production of colicine Ib and KNP resistance. These characters varied both in vivo and in vitro. Variability of resistotype characters, on the other hand, was observed in only 28 (9%) episodes, 14 of which possibly represented examples of mixed or sequential infections.

For accurate epidemiological tracing of strains of Sh. sonnei in a community, resistotyping, the technique showing the greatest discrimination and least variability of the four tested, should be included as the principal typing method.

We simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3–47·7] and 44% (95% CI 36·4–51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3–49·0) and 36% (95% CI 27·9–44·0), respectively. Simulation of risk may be useful as a tool to classify local and regional hospitals according to their risk of nosocomial TB transmission, and to facilitate the design of hospital infection control plans.