During the surveillance of influenza pandemics, underreported data are a public health challenge that complicates the understanding of pandemic threats and can undermine mitigation efforts. We propose a method to estimate incidence reporting rates at early stages of new influenza pandemics using 2009 pandemic H1N1 as an example. Routine surveillance data and statistics of travellers arriving from Mexico were used. Our method incorporates changes in reporting rates such as linearly increasing trends due to the enhanced surveillance. From our results, the reporting rate was estimated at 0·46% during early stages of the pandemic in Mexico. We estimated cumulative incidence in the Mexican population to be 0·7% compared to 0·003% reported by officials in Mexico at the end of April. This method could be useful in estimation of actual cases during new influenza pandemics for policy makers to better determine appropriate control measures.

Oral fluid is a non-invasive biological sample, which can be returned by post, making it suitable for large-scale epidemiological studies in children. We report our experience of oral fluid collection from 14 373 preschool-aged children in the UK Millennium Cohort Study. Samples were collected by mothers in the home setting following the guidance of trained interviewers, and posted to the laboratory. Samples were received from 11 698 children (81·4%). Children whose mothers were of Black Caribbean ethnicity and who lived in non-English-speaking households were less likely to provide a sample, and those with a maternal history of asthma more likely to provide a sample [adjusted risk ratio (95% CI) 0·85 (0·73–0·98), 0·87 (0·77–0·98) and 1·03 (1·00–1·05) respectively]. Collection of oral fluid samples is feasible and acceptable in large-scale child cohort studies. Formal interpreter support may be required to increase participation rates in surveys that collect biological samples from ethnic minorities.

The aim of this study was to demonstrate the epidemiological use of multiple correspondence analysis (MCA), as applied to tuberculosis (TB) data from North East London. Data for TB notifications in North East London primary care trusts (PCTs) between the years 2002 and 2007 were used. TB notification data were entered for MCA allowing display of graphical data output (n=4947); MCA analyses were performed on the whole dataset, by PCT, and by year of notification. Graphical MCA output displayed variance of data categories; clustering of variable categories in MCA output signified association. Clustering patterns in MCA output demonstrated different associations by year of notification, within PCTs and between PCTs. MCA is a useful technique for displaying association of variable categories used in TB epidemiology. Results suggest that MCA could be a useful tool in informing commissioning of TB services.

A comparative study of the susceptibility of monkey kidney, Hep 2 and HeLa cells to enteroviruses and adenoviruses is made. It seems that this Hep 2 cell line is as effective as the monkey kidney cells in their susceptibility to vaccine strains of polioviruses and far better than monkey kidney cells in their susceptibility to strains of ECHO 6 and ECHO 11 from clinical material. It is as effective as, or slightly better than, HeLa cells for the isolation of adenoviruses. It also compares favourably with monkey kidney cells for the isolation of other enteroviruses.

We are most grateful to Glaxo Laboratories Ltd. for the supplies of monkey kidney cells used in this investigation.

1. The susceptibility of mice of different ages to intramuscular, intraperitoneal, and oral administration of EMC virus, and to intracerebral and intramuscular injection of both the Texas and the Connecticut-5 strains of Coxsackie virus have been studied. In all cases susceptibility decreases with age. The development of resistance to a given virus may vary in rate and extent according to the route by which the virus is given.

2. The multiplication of small amounts of EMC virus in muscle, and of the Texas and Connecticut-5 strains of Coxsackie virus in both muscle and brain, has been studied in mice of different ages. A very high degree of multiplication of all three viruses was observed in both muscle and brain of young mice, but no significant multiplication of the EMC virus in older muscle could be detected with these small inocula, nor of either of the Coxsackie strains in older muscle or brain.

3. Multiplication of EMC virus in young mice was shown to take place within the muscle itself. Haemagglutination tests showed that less haemagglutinin, as well as less infective virus, was produced in the muscles of older mice following the injection of small amounts of virus.

4. Multiplication of EMC and GDVII viruses could be demonstrated even in older mice if a sufficiently large amount of virus was inoculated initially.

5. The rapid initial disappearance of infectivity from the site of inoculation was shown to be mainly due to dispersal of inoculated virus around the body.

6. The simplest hypothesis which will accommodate the observed data on virus multiplication and on the development of resistance with age appears to be that the accessibility of the host cell to virus decreases with age. We found no evidence that the ability of the host cell to support virus multiplication declines with age.

This work was done in the Department of Zoology, Oxford University. One of us was in receipt of a Medical Research Council training grant. The expenses of the research were met by a grant from the Nuffield Foundation, to whom we should like to express our gratitude.

A total of 17 isolates of Vibrio mimicus from patients, 29 from environment and 2 from food was examined for toxigenicity. Sixteen (94%) clinical isolates and one (50%) from food produced TDH-like toxin, whereas none of the environmental isolates did so. The food from which V. mimicus with TDH-like toxin production was isolated, was one which had caused food poisoning. Only one environmental strain produced CT-like toxin, whilst ST-like toxin was not detected from any strains tested.

An account is given of two cows which were concerned in milk-borne Streptococcus outbreaks at Mørkøv (Denmark) and Doncaster (England) respectively, and. which were afterwards kept under close observation. The Danish cow excreted Str. pyogenes from the affected quarter for at least 13 months, including a dry period of about 3 months; the other animal excreted similar streptococci for about 6 weeks. In both cases there were stages when symptoms of mastitis were either not evident or not pronounced, although the milk was known to be infective.

We argue that the spread of unhealthy behaviour shows marked similarities with infectious diseases. It is therefore interesting and challenging to use infectious disease methodologies for studying the spread and control of unhealthy behaviour. This would be a great addition to current methods, because it allows taking into account the dynamics of individual interactions and the social environment at large. In particular, the application of individual-based modelling holds great promise to address some major public health questions.

Surveys for respiratory virus antibodies in the Jamaican population have shown that adenovirus, respiratory syncytial virus and parainfluenza types 1 and 3 virus antibodies are acquired early in life. The incidence of haemagglutination-inhibiting antibodies to parainfluonza viruses increases rapidly with age and almost all adults possess parainfluenza type 3 antibody, usually in high titre. Parainfluenza type 1 antibodies are only slightly less common. Complement-fixing antibodies to the adenovirus group were also observed to increase in incidence with age.

Complement-fixing antibody to respiratory syncytial virus was less common in Jamaican sera than antibody to the other respiratory viruses described here. The highest titres were observed in the youngest age-group.

The experiments with individual strains in sterile water show a marked difference between the behaviour of the streptococci and B. coli. In all cases the streptococci diminished in numbers and in two experiments were practically eliminated at the end of 2 weeks while in the other two they did not survive very much longer. On the other hand the B. coli strains although in a medium which contained little or no organic matter, and which was not in any sense a nutrient medium, showed in every case multiplication, in most extensive multiplication. This was rather contrary to our anticipations as although we were prepared for prolonged survival under conditions of freedom from com peting bacteria we did not anticipate such marked increase in numbers. In Exp. XIX the bacillus tested was still present over fifty-fold of the original number at the end of 11 weeks.

We have given some attention to the characters of the surviving types of B. coli in the tank experiments. Generally speaking they were quite normal in respect of fermentation reactions but on three occasions, Exps. XIII, XV and XX, the capsulated “high ratio” (CO2: H) coli of Clark and Lubbs were found, and in Exps. IV, XX and XXI the surviving organisms isolated were also capsulated but not “high ratio” organisms. It appears possible that the capacity to form capsules has something to do with the viability of these organisms and Exps. XXII and XXIV are evidence in this direction, but it is to be noted that the surviving B. coli in Exp. XVI after 7 weeks produced no definite capsule when grown in milk.

In Exp. XX the original sewage was plated out upon lactose neutral red bile salt agar and 10 strains of B. coli isolated of which 50 per cent, showed capsule formation. Fourteen days later 11 strains were isolated from the sewage tank water and of these 90 per cent, were weak lactose fermenters and showed no capsule formation. In the same experiment 2 strains isolated after 4 weeks and another after 5 weeks showed definite capsule formation. The ultimate B. coli survivors were a pparently all capsulated organisms, although at the start as many non-capsulated as capsula ted organisms were present.

The tank experiments with excreta or sewage added to a large bulk of water yielded minor differences in the individual experiments, but in general they all show a rapid diminution and elimination of the streptococci and a continuous but not quite so rapid diminution inthe number of B. coli. With the latter it was more common to find persistence in small numbers for a period extending to many weeks. The elimination of the streptococci was particularly uniform and rapid. At the end of 2 weeks in only one experiment were they present in more than insignificant numbers.

While the diminutioji was rather more rapid for excreta than for sewage for both streptococci and B. coli, no definite constant differences in relation to the kind of contamination could be made out.

The decline curves of both organisms agree very closely as can be most readily seen if the figures are plotted out as graphs. Three of the experiments, in which the initial numbers of B. coli and streptococci were identical, and also Exp. XI are set out in this way.

The available data is hardly extensive enough to enable deductions to be drawn other than broad and general ones, but the facts add confirmation to the view that the presence of either streptococci or B. coli in considerable numbers, i.e. in 1 or even 10 c.c. of a water, can only indicate contamination considerable in amount and of recent origin.

In particular the finding of streptococci in any numbers can be accepted as indicating considerable and recent contamination. We consider that the streptococcus determination is very valuable on its positive side as an indication of recent contamination. As a means of judging of the recency of the contamination it is even more valuable than the B. coli enumeration.

Put another way our experimental data shows that in nearly every case there is a marked diminution in the number of both B. coli and streptococci at the end of even 1 week, so that it.follows that when these organisms are found in large numbers the contamination must have been either very recent or especially abundant.

It is paramount to understand the epidemiology of chronic hepatitis B to inform national policies on vaccination and screening/testing as well as cost-effectiveness studies. However, information on the national (Scottish) prevalence of chronic hepatitis B by ethnic group is lacking. To estimate the number of people with chronic hepatitis B in Scotland in 2009 by ethnicity, gender and age, the test data from virology laboratories in the four largest cities in Scotland were combined with estimates of the ethnic distribution of the Scottish population. Ethnicity in both the test data and the Scottish population was derived using a name-based ethnicity classification software (OnoMAP; Publicprofiler Ltd, UK). For 2009, we estimated 8720 [95% confidence interval (CI) 7490–10 230] people aged ⩾15 years were living with chronic hepatitis B infection in Scotland. This corresponds to 0·2% (95% CI 0·17–0·24) of the Scottish population aged ⩾15 years. Although East and South Asians make up a small proportion of the Scottish population, they make up 44% of the infected population. In addition, 75% of those infected were aged 15–44 years with almost 60% male. This study quantifies for the first time on a national level the burden of chronic hepatitis B infection by ethnicity, gender and age. It confirms the importance of promoting and targeting ethnic minority groups for hepatitis B testing.

An international collection of 419 isolates of Salmonella agona was phage typed, biotyped and colicine typed. Of 16 recognized phage types, 15 were represented. Three phage types (I, V and XVI) accounted for 84% of all isolates, were widely distributed and may be interconvertible. Biotyping afforded little type differentiation; thus 92·6% of the isolates belonged to biotype 1 a. A rhamnose non-fermenting variant line (of biotype 5a) became established in Zaire from 1979 to 1980. A maltose late-fermenting line of biotype 1 a, isolated in Scotland in 1974, did not thereafter become established. Two Col+ lines (producing colicine I b) accounted for 45 of 68 colicinogenic isolates. The implication of type diversification and the phylogenetic significance of these findings are discussed.

1. Normal human sera have no natural bactericidins active against strains of gonococci.

2. Normal sera from eleven other mammalian species showed a powerful bactericidal action against various strains of gonococci.

3. The serological heterogeneity of the gonococcus group revealed by agglutination and complement fixation is again demonstrated in the bactericidal test with immune antiserum.

4. There is a steady rise in the incidence of positive bactericidal action in the sera of patients following the progress of infection with the gonococcus.

5. The probable significance of these bactericidins, natural and immune, discussed.

Acknowledgments. I wish to express my gratitude to Dr Ledingham for the facilities for work granted me at the Lister Institute and to Dr Schiitze for his kind help and critical advice during the progress of this investigation.

Bloodstream infection (BSI), caused by Klebsiella pneumoniae, is associated with high morbidity and mortality, where the pks gene cluster plays a major role in their occurrence and prevalence. Information on the prevalence and characteristics of this gene cluster in K. pneumoniae is currently limited in mainland China. We therefore undertook a multicentre longitudinal study which revealed the prevalence, overall, community-onset and hospital-acquired BSI to be 20.5%, 28.3% and 13.0%, respectively. Compared to pks-negative, pks-positive isolates were significantly more susceptible to antimicrobial agents with a low incidence (5.1%) of multidrug-resistance and with infrequent extended-spectrum beta-lactamase (ESBL) production. Among pks-positive isolates, ST23 (78/117) and ST65 (20/117) were the dominant sequence types, and the majority harboured virulence genes. Community-onset BSI patients infected with pks-positive isolates had a higher proportion of liver abscesses and a lower proportion of biliary obstructions (P < 0.05). The pks-positive isolates were mostly sporadic in the phylogenetic tree, with a 65.8 and 47.0 average allele difference between Clade 1 and Clade 2, respectively. We concluded that although pks-positive K. pneumoniae were generally susceptible to antimicrobials, the high prevalence of such isolates in community cases and the genotoxicity, merits further investigation.

Between 1961 and 1972, 4547 independent strains of Staphylococcus aureus isolated from one hospital were examined for phage type. After 1967 there was a decline in the number of strains received, which we consider reflects a decline in the number of infections in the hospital, and which was largely accounted for by a great reduction in the number of strains in four ‘epidemic’ types. Overall, the number of multiple-resistant staphylococci received also declined; this was in part due to the decline in the epidemic types and in part to a reduction in the proportion of multiple-resistant strains of all types.

A significant proportion of Q fever patients from the first Dutch Q fever outbreak in 2007 showed impairment in health status up to 1 year after infection. Interested in whether this decrease in health status persisted, we set out to determine the health status in the same cohort of patients, 4 years after primary infection and to compare health status scores at the individual patient level between 1 and 4 years follow-up. Health status was assessed with the Nijmegen Clinical Screening Instrument (NCSI). Patients were serologically tested to exclude patients with possible, probable or proven chronic Q fever. Results on the NCSI sub-domains at group level [2008 (n = 54) and 2011 (n = 46)] showed a persistent significant percentage of patients exhibiting clinically relevant (‘severe’) scores for all NCSI sub-domains. After 4 years, undue fatigue was present in 46% and exactly half of all patients experienced a severely impaired general quality of life. Patients with NCSI scores available in both 2008 and 2011 (n = 37) showed no difference in all sub-domain scores, except for a small decrease in dyspnoea emotions in 2011. In this group, a significant proportion of patients either improved or worsened in one or more sub-domains of health status. We conclude that at the group level, health status of Q fever patients remained impaired 4 years after primary infection. At the individual patient level, health status may change.

Contamination of a laboratory environment with pathogenic or non-pathogenic micro-organisms may be relevant to safety of technicians and quality of technical performance. Two widely separated incidents in 1968 and 1974 initiated a study of aspects of the laboratory environment. Water-baths, water of syneresis and portions of salmonella cultures spurting out of the sterilizing flame were examined. The water of water-baths was shown to be contaminated from the fluid cultures incubated in them. This raised questions of potential cross-contamination and reporting of false positives. Water of syneresis was sometimes contaminated with salmonellas. A few quantitative counts were made. The range of counts varied between 16 salmonellas per ml. and 13,000,000 salmonellas per ml. Five hundred portions of salmonella cultures and 571 portions of Shigella sonnei cultures which had spurted from the sterilizing flame were examined. All these samples failed to grow salmonellas or shigellas.

Precautions necessary to avoid environmental contamination are briefly discussed.

Samples of blended mutton tissue in small polyvinyl chloride sachets were incubated in water baths for different times and at varying temperatures. The temperature of each bath was recorded accurately throughout each experiment. Using equations previously derived for the lag and generation times of coliform organisms in blended mutton tissue, the expected increases of these bacteria were calculated from the time/temperature recordings. These were compared with the data obtained from plate counts made on the tissue samples in the sachets before and after incubation. The studies were done with a strain of Escherichia coli, one of Salmonella lyphimurium and the coliform organisms naturally present on sheep carcasses processed in a commercial abattoir. The calculated growth agreed closely with that measured. Therefore, if mutton, after overnight chilling, is warmed again to temperatures within the growth range of these bacteria, the possible increases in the numbers of cells present can be calculated directly from time and temperature measurements.

The implications for the present codes of practice in abattoirs are discussed.

A dipthericin typing scheme has been constructed using 441 strains of Corynebacterium diptheriae isolated in eastern Australia from 1962 to 1971. Ten types have been distinguished using seven strains of C. diphtheriae and two strains of C. belfanti as indicators of the diphthericins produced by the newly isolated strains. Strains grouped into types L2, L3 and L3a were found only in Melbourne and types L1 and L4 were predominant in Sydney. Type L5 strains were isolated intermittently throughout the period of study and were found in all eastern states. Numerical analysis of the characteristics of the strains suggests that associations exist between, on the one hand, diphthericin type and, on the other hand, bacteriophage type, serotype and biochemical activity.

If a medium containing either 1 per cent. ammonium succinate or 1 per cent. ammonium fumarate together with certain inorganic salts be inoculated with B. pyocyaneus and incubated aerobically at 37° C. a vigorous growth of the organism will ensue, the rates of growth in both cases not being markedly different from each other. If the growth be allowed to proceed for a fortnight, analysis of the media shows that essentially similar products (mixtures of the lower fatty acids) have been produced in both cases. If the growth be allowed to proceed for not longer than three days, analysis shows that in the succinate medium over 80 per cent. of the succinic acid has not been utilised, whilst in the other medium the entire fumaric acid has disappeared, giving rise in its stead to pyruvic acid which is further utilised as growth proceeds(1). Quantitative data support the view that the breakdown of succinic acid occurs through the intermediate production of fumaric acid, the rate of fermentation of fumaric acid being greater than that of succinic acid, so that fumaric acid is not detected among the products of fermentation of succinic acid. If this view is true, it should be possible to show that B. pyocyaneus has the power of oxidising succinic acid to fumaric acid. It is clear that the proliferating organism cannot be used to demonstrate this experimentally, for the fumaric acid is utilised as quickly as it is formed. Hence it is necessary to use the organism in such a condition that proliferation is completely (or almost completely) eliminated. Under such circumstances the fumaric acid will accumulate and its detection will be made possible.