This study investigated the relationships between Legionnaires' disease (LD) incidence and weather in Glasgow, UK, by using advanced statistical methods. Using daily meteorological data and 78 LD cases with known exact date of onset, we fitted a series of Poisson log-linear regression models with explanatory variables for air temperature, relative humidity, wind speed and year, and sine-cosine terms for within-year seasonal variation. Our initial model showed an association between LD incidence and 2-day lagged humidity (positive, P = 0·0236) and wind speed (negative, P = 0·033). However, after adjusting for year-by-year and seasonal variation in cases there were no significant associations with weather. We also used normal linear models to assess the importance of short-term, unseasonable weather values. The most significant association was between LD incidence and air temperature residual lagged by 1 day prior to onset (P = 0·0014). The contextual role of unseasonably high air temperatures is worthy of further investigation. Our methods and results have further advanced understanding of the role which weather plays in risk of LD infection.

Extreme rainfall events may cause pluvial flooding, increasing the transmission of several waterborne pathogens. However, the risk of experiencing clinically overt infections following exposure to pluvial floodwater is poorly estimated. A retrospective cross-sectional survey was performed to quantify the occurrence of self-reported gastrointestinal, influenza-like illness (ILI) and dermatological complaints, and the frequency of visits to the general practitioner (GP), during a 4-week observation period following pluvial flooding at seven locations in The Netherlands. Questionnaires were sent to 817 flooded households, 149 (17%) of which returned the questionnaire reporting information for 199 participants. Contact with floodwater was significantly associated with increased occurrence of gastrointestinal [odds ratio (OR 4·44)], ILI (OR 2·75) and dermatological (OR 6·67) complaints, and GP visits (OR 2·72). Having hand contact with floodwater was associated with gastrointestinal and dermatological complaints, whereas ILI complaints were associated with being engaged in post-flooding cleaning operations and having walked/cycled through floodwater. This study shows that floodwater-associated diseases occur in urban settings following extreme rainfall events in a high-income country. As pluvial floods are expected to escalate in the future due to global climate change, further research is warranted to determine the disease burden of pluvial flooding and to assess the effect of different interventions, including raising awareness among stakeholders.

Globally, the prevalence of tuberculosis (TB) disease is higher in males. This study examined the effect of sex and age on Mycobacterium tuberculosis (Mtb) infection. Demographic and exposure data were collected on household contacts of sputum smear-positive pulmonary TB patients in Brazil. Contacts with tuberculin skin test induration ⩾10 mm at baseline or 12 weeks were considered Mtb infected. The study enrolled 917 household contacts from 160 households; 508 (55.4%) were female, median age was 21.0 years (range 0.30–87.0) and 609 (66.4%) had Mtb infection. The proportion infected increased with age from 63.3% in girls <5 years to 75.4% in women ⩾40 years and from 44.9% in boys <5 years to 73.6% in men ⩾40 years. Multivariable modelling showed the odds of infection increased between age 5 and 14 years among female contacts (OR 1.5 per 5-year age increase; 95% CI 1.1–2.2; P = 0.02) and between ages 0–4 and 15–39 years among male contacts (OR 2.7, 95% CI 0.83–8.9 and 1.1, 95% CI 0.99–1.3 per 5-year age increase; P = 0.10, 0.07, respectively). The study suggests that the age at which Mtb infection increases most is different in females compared with males. Studies are needed to explore whether these findings are due to differences in host susceptibility, exposure outside the household or other factors.

An outbreak of salmonellosis due to Salmonella saint-paul in two dairy herds was first detected during routine examination of calves soon after calving; infection reached 100% amongst calves and up to 60% amongst milking cows. Excretion by cows continued for over 12 months and by calves for up to 18 months.

The most important factor in controlling the spread of infection was reduction of environmental contamination by removal of carriers, prompt antibiotic treatment of sick calves and reduction in stocking densities.

Twelve strains of Bordetella pertussis, of various serotypes, were tested by agglutination with serial dilutions of six antisera which were thought by their donor to be monospecific for six distinct agglutinogens.

The first three sera were shown, by agglutination of the twelve donated strains and of standard pertussis serotypes, to be monospecific for the three well-recognized major agglutinogens (factor 1, factor 2, factor 3).

The ‘factor 4’ serum gave weak agglutination, but only of strains that possessed factor 2, though not all of such strains. This suggested that it may be a distinct minor component of factor 2.

The ‘factor 5’ serum was very weak, and gave agglutination only with a few of the factor 2 strains.

The titres of the ‘factor 6’ serum were very closely parallel to those of the factor 3 serum, and it may be inferred that these ‘factors’ probably constitute a single antigenic entity.

Seven of the twelve donated strains were shown to be mixtures of two or more serotypes, offering an explanation for discrepancies in serological tests involving the use of these strains on different occasions.

It seems likely that ‘factors 5 and 6’ do not actually exist; and, since ‘factor 4’ is only a minor component of factor 2, any protective role that it may have would probably be covered by the presence of factor 2 in vaccine.

(1) The source, cultural characters and serological properties of a new food-poisoning type of Salmonella are described.

(2) The value is emphasised of Andrewes' discovery of the group and specific phases in Salmonellas.

(3) Alteration of phase from group to specific can be produced by growth in group serum and vice versa. This device is useful in determining the sero logical type of strains which persistently appear in the group phase only.

Cross-linked poly(N-benzyl-4-vinylpyridinium bromide) (BVP resin) was found to be very efficient in removing pathogenic human viruses from aqueous solution. In batch removal experiments using 50 g/1 of BVP resin at 35 °C. the level of infectivity in suspensions of enterovirus. herpes simplex virus, poliovirus, and human immunodeficiency virus was reduced 1000–100000 fold during a 2 h period. Those of coxsackievirus and echovirus were reduced 60–600 fold during 1 h contact. The haemagglutination titres of solutions of human rotavirus, influenza virus, human adenovirus. and Japanese encephalitis virus were reduced 16–256 fold during 30 min of contact. In removal experiments by a continuous flow column method for poliovirus. enterovirus. and coxsackievirus with initial infectivities of less than 105/ml, the infectivity of these viruses was no longer detectable in the effluent solution. For poliovirus, coxsackievirus, and echovirus with initial infectivities higher than 106, 99·8–99·9998% of the input viruses was removed as indicated by the reduction of infectivity.

Airborne-particle transfer has been studied in a burns unit using potassium iodide particles. The observed rates of transfer were in good agreement with the values predicted by a theoretical model.

An estimate of the average transfer between rooms under conditions of normal activity and with correctly functioning ventilation showed that the isolation system was highly efficient, the proportion transferred being probably less than 1 in 105. However, the ventilation often did not function as designed and under these conditions the efficiency was reduced by a maximum of a factor of ten. These rates of transfer do not seem great enough to account for the high rate of cross-infection found in this unit.

Underreporting of hepatitis A infection in England may be high and a number of outbreaks have occurred undetected by routine surveillance. We evaluated surveillance of hepatitis A cases by employing capture–recapture analysis on data from two distinct outbreaks of hepatitis A. The overall reporting of cases of hepatitis A was 81·7% (95% CI 55·3–95) in the first outbreak in North East England and reporting through Lab Base was 65·7% (95% CI 42·8–76·4). In the second outbreak in the East Midlands the overall reporting of hepatitis A cases was 27·8% (95% CI 19–38·7) and through Lab Base 16·6% (95% CI 11·4–23·1). Underreporting of hepatitis A cases is high. Public health interventions exist to prevent and control outbreaks of hepatitis A. The lack of reliable data on incidence and prevalence hampers effective public health management of this disease.

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

1. In the list showing all substances yet tested in the order of their spermicidal powers, the first four substances are all quinones.

2. In the dihydroxybenzenes and their derivatives, the para-position of the two hydroxyl groups confers high spermicidal powers.

3. In the trihydroxybenzenes and their derivatives, the para-position of two of the three hydroxyl groups confers high spermicidal powers.

4. The introduction of a methyl group into quinones and into the di- and trihydroxybenzenes in certain positions increases the spermicidal power.

5. In the hydroxybenzaldehydes and their derivatives, the ortho-position of the hydroxyl and aldehyde groups confers high spermicidal powers.

6. Among the substances so far tested which may be found to be of practical use are orbhovanillin and methoxytoluquinone. These are highly spermicidal, sufficiently soluble and stable in solution. It remains to be seen whether they are harmless to the vagina.

The aims were to assess the prevalence of HIV infection among young adult heroin users, including injecting heroin users (IHUs) and non-injecting heroin users (NIHUs), and to explore the differences by gender and other factors. The design was a cross-sectional cohort study between April 2001 and December 2003, which included 961 current heroin users (HU), aged 18–30 years: 422 in Madrid, 351 in Barcelona and 188 in Seville; 621 were IHUs and 340 were NIHUs. All were street-recruited by chain referral methods. Face-to-face interviews were conducted using a structured questionnaire with computer-assisted personal interviewing (CAPI). Samples for HIV testing (dried blood spot) were collected and tested with ELISA and Western Blot. Bivariate, logistic regression, and classification and regression tree analyses were performed. The overall prevalence of HIV infection among IHUs was 25·8% (95% CI 22·3–29·3) [32·4% (95% CI 26·6–38·1) in Madrid, 20·5% (95% CI 15·6–25·4) in Barcelona, and 20·6% (95% CI 9·8–31·4) in Seville], whereas in NIHUs it was 4·0% (95% CI 2·1–6·7), with no differences among cities. The prevalence was significantly higher in women than in men in NIHUs (10·9%, 95% CI 4·3–17·5 vs. 1·7%, 95% CI 0·5–4·2) and was non-significantly higher in IHUs (30·4%, 95% CI 23·0–37·8 vs. 24·1%, 95% CI 20·1–28·1). HIV prevalence in short-term IHUs was 12·9% (CI 8·8–17·02), with no differences among cities. In the logistic analysis, the variables associated with infection in IHUs were ever having injected with used syringes (OR 3·4, 95% CI 2·2–5·3), ever having been in prison (OR 2·6, 95% CI 1·6–4·0), and heroin as the first drug injected at least weekly (OR 2·3, 95% CI 1·1–4·5). Factors positively associated with HIV infection in NIHUs were female sex (OR 8·7, 95% CI 2·6–29·2) and age >25 years (OR 3·1, 95% CI 0·9–11·1), while primary educational level was inversely associated (OR 0·26, 95% CI 0·1–0·9). Although there are important geographic differences, HIV prevalence in IHUs remains high, even in short-term IHUs, whereas it was almost six times lower in NIHUs. The prevalence in women is higher than in men, particularly among NIHUs. A wide range of preventive strategies should be developed, aimed primarily at empowering women to negotiate safe sex.

Targets for maximum acceptable levels of Salmonella in pigs and pork are to be decided. A stochastic simulation model accounting for herd and abattoir information was used to evaluate food safety and economic consequences of different surveillance and control strategies, based among others on Danish surveillance data. An epidemiological module simulated the Salmonella carcass prevalence for different scenarios. Cost-effectiveness analysis was used to compare the costs of the different scenarios with their expected effectiveness. Herd interventions were not found sufficient to attain Salmonella carcass prevalence <1%. The cost-effectiveness of abattoir interventions changed with abattoir size. The most cost-effective strategy included the use of steam vacuum and steam ultrasound. Given uncertainty of the effect of steam vacuum and steam ultrasound, model results should be updated as more information becomes available. This framework contributes to informed decision-making for a more cost-effective surveillance and control of Salmonella in pigs and pork.

Classical swine fever (CSF) is a disease of pigs that imposes major hardship on the industry of infected regions. The recent history of CSF epidemics suggests that animal movements remain the main source of CSF virus (CSFV) infection for susceptible populations in Europe. This study presents an assessment of the risk of introducing CSFV into Spain through the importation of live susceptible animals. Results suggest that, if prevailing conditions persist, introduction of CSFV into Spain is likely to occur on average every 9 years and that introduction is almost three times more likely to occur via domestic pigs than through wild boars. The highest risk was concentrated in March and in the Northeastern provinces of Spain. Results were consistent with the time and location of previous CSFV introductions into the country. The methodology and the results presented here will contribute to improve the CSF prevention programme in Spain.

Streptococcus pneumoniae is the leading bacterial cause of life-threatening infections in infants. Although antibiotic resistance affects management of pneumococcal infections, few data on patterns of resistance are available for India. We examined nasopharyngeal carriage of antibiotic-resistant pneumococci in 464 South Indian infants between 2 and 6 months. Newly acquired serotypes were screened for susceptibility to cotrimoxazole, erythromycin and penicillin using disk diffusion. Cumulative prevalence of pneumococcal carriage rose from 53·9% at 2 months to 70·2% at 6 months. The prevalence of strains that were not susceptible to penicillin, co-trimoxazole and erythromycin was 3·4, 81·1 and 37·2%, respectively. Carriage of erythromycin non-susceptible strains declined significantly between ages 4 months and 6 months (44·1 vs. 10·7%). More than 87% of the isolates screened were non-susceptible to [ges ]1 antibiotic. Serogroups/types that were most frequently non-susceptible to 1 or more antibiotics were 6, 9, 14, 19 and 23. Less than 1% of the isolates were multi-drug resistant. Widespread use of antibiotics in South India has resulted in S. pneumoniae becoming non-susceptible to some commonly used antibiotics. Monitoring trends in antibiotic susceptibility and making antibiotics available only through prescription from a health care worker may slow the spread of resistant pneumococci and improve management of pneumococcal infections in South India.

1. An explosive outbreak of gastroenteritis that affected 40–50% of people in a town of 10,800 inhabitants (Montrose) is described.

2. There is epidemiological evidence that the outbreak was water-borne. The chlorination of the water supply was faulty at the time of the outbreak.

3. Echovirus type 30 and two types of Coxsackie B viruses were isolated from sixteen out of thirty-two patients examined.

4. Shigella sonnei was isolated from the faeces of 110 out of 262 patients and contacts examined. Fifty-six strains tested for colicine activity were all colicine type 4 and had the same antibiotic sensitivity pattern.

5. This particular strain of Shigella sonnei (Montrose strain) spread to surrounding areas, although it disappeared quickly from Montrose.

6. The problem of inactivating virus in water supplies contaminated with sewage is discussed briefly.

We wish to acknowledge the help given by the general practitioners of Montrose and the staff of the Public Health Department of the County of Angus in the collection of specimens and information during the outbreak. We would also like to thank the Laboratory staffs of the diagnostic laboratory and virus laboratory of the Bacteriology Department, University of Dundee and the staff of the laboratory, Stracathro Hospital, for invaluable assistance. We are indebted to Dr R. R. Gillies, Epidemiology Unit, Bacteriology Department, University of Edinburgh, who kindly carried out colicine typing for us and supplied us with strains from his collection, and to Dr R. M. Gordon, Senior Medical Officer, Scottish Home and Health Department and Mr H. F. Scrimgeour, M.I.C.E., A.I.W.E., Engineering Inspector Scottish Development Department, for their assistance during the investigation.

Improving access to tuberculosis (TB) care and ensuring early diagnosis are two major aims of the WHO End TB strategy and the Collaborative TB Strategy for England. This study describes risk factors associated with diagnostic delay among TB cases in England. We conducted a retrospective cohort study of TB cases notified to the Enhanced TB Surveillance System in England between 2012 and 2015. Diagnostic delay was defined as more than 4 months between symptom onset and treatment start date. Multivariable logistic regression was used to identify demographic and clinical factors associated with diagnostic delay. Between 2012 and 2015, 22 422 TB cases were notified in England and included in the study. A third (7612) of TB cases had a diagnostic delay of more than 4 months. Being female, aged 45 years and older, residing outside of London and having extra-pulmonary TB disease were significantly associated with a diagnostic delay in the multivariable model (aOR = 1.2, 1.2, 1.2, 1.3, 1.8, respectively). This study identifies demographic and clinical factors associated with diagnostic delay, which will inform targeted interventions to improve access to care and early diagnosis among these groups, with the ultimate aim of helping reduce transmission and improve treatment outcomes for TB cases in England.

In November 2013, national public health agencies in England and Scotland identified an increase in laboratory-confirmed Salmonella Mikawasima. The role of proton pump inhibitors (PPIs) as a risk factor for salmonellosis is unclear; we therefore captured information on PPI usage as part of our outbreak investigation. We conducted a case-control study, comparing each case with two controls. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression. Thirty-nine of 61 eligible cases were included in the study. The median age of cases was 45 years; 56% were female. Of these, 33% were admitted to hospital and 31% reported taking PPIs. We identified an association between PPIs and non-typhoidal salmonellosis (aOR 8·8, 95% CI 2·0–38·3). There is increasing evidence supporting the existence of an association between salmonellosis and PPIs; however, biological studies are needed to understand the effect of PPIs in the pathogenesis of Salmonella. We recommend future outbreak studies investigate PPI usage to strengthen evidence on the relevance of PPIs in Salmonella infection. These findings should be used to support the development of guidelines for patients and prescribers on the risk of gastrointestinal infection and PPI usage.

1. Whooping cough is now in London the most important epidemic disease of childhood in causing physical suffering, loss of school attendance, impairment of physique and mortality.

2. The mean annual incidence of whooping cough in children under 10 in Battersea during the quinquennium 1925–9 is estimated to have been about 60 per 1000 living, and the fatality rate 1·26 per 100 cases. The fatality rates in the first two years of life were estimated to be 4·0 and 3·3 respectively, at ages 2 to 5, 0·7 and at ages 5 to 10, 0·2 per 100 cases.

3. Epidemics of whooping cough in Battersea and Greenwich tend to have a biennial periodicity; a summer epidemic is often immediately followed by or merges into a winter epidemic subsiding by midsummer, and then follows a year of low incidence, so that the total incidence of cases in successive years from midsummer to midsummer shows an alternation of epidemic and interepidemic years.

4. Epidemics do not always run concurrently in areas of London separated by several miles; the spread is checked to some extent by barriers to free communication and small districts thus occasionally escape an epidemic, or an interval of several months may separate the epidemic peaks in districts a mile or so apart.

5. The view that the epidemic cycle in whooping cough can be explained by a periodic reduction of the proportion of children not previously attacked below some critical limit, is shown to be untenable. Both the termination of epidemics and their periodicity can be explained by the occurrence of a latent immunisation of contacts as in measles, such immunity only lasting about 1 year instead of 2 or 3.

6. The occurrence of such a transient latent immunisation is indicated by (a) measurement of the rise and fall of apparent infectiousness of cases to other children in the same house during 6 years in Battersea, (b) measurement of the frequency of second cases in houses after different intervals of time during a decade in Greenwich, and (c) analysis of the attack rates amongst home contacts in Holborn and Battersea during several years following exposure to infection as compared with those among control groups of children. These phenomena would be difficult to explain as resulting from a “cycle of activity” of the organism.

7. In London as a whole a special enquiry into the previous histories of school entrants proves that 44 per cent. of children have an attack of whooping cough before their fifth birthday. According to Battersea records 27·7 per cent. are notified or reported to the Public Health authority as having whooping cough by this age, and 42·3 per cent. by the tenth birthday. It is concluded that in that borough about 60 per cent. of the true incidence is notified at ages under 4, about 72 per cent. at age 4, and 90 per cent. at ages 5 to 10 when school supervision is fairly complete. At all ages under 10 the recorded incidence in Battersea represents about 70 per cent. of the true incidence.

8. It follows that about 60 per cent. of London children have whooping cough by the tenth year, and about 61 per cent. at some time during life, this proportion being rather lower than estimates made from histories given by parents in a group of American towns. The bulk of the remaining 40 per cent. must escape attack by virtue of some kind of immunity rather than by avoidance of contact with infection through life, and a part of these no doubt escape by the repeated acquisition of transient latent immunity during epidemics, and the remainder by virtue of an inherent immunity to the disease.

9. During the year following an epidemic the proportion of children under 10 who are susceptible is approximately doubled and again halved during the next epidemic. This must be mainly due to temporary latent immunisation during an epidemic of x children to each one attacked, the value of x lying between the limits 1 and 4, this depending upon the unknown proportion who are inherently immune. If the bulk of the two-fifths of all children who escape attack have inherent immunity, as is suggested but not proved by the data, then the ratio of latent to recognisable infections lies between 1 and 2.

10. Superposed upon the gradual rise and fall of infectiousness believed to be due to these immunity changes, there occurs a sudden rise at the commencement of an epidemic which must be attributed to an enhanced real infectiousness. This probably arises from a sudden increase in activity of the organism itself under seasonal influences setting in at the moment when the herd immunity becomes insufficient to withstand the infection pressure, so that the balance is upset and the epidemic begins.

11. These findings are similar to those for measles, the chief differences being, (i) epidemics are usually spread over a year instead of 6 months; (ii) latent immunity apparently lasts about a year instead of 2 or 3; (iii) about 60 per cent. of children are attacked at some time during life instead of about 90 per cent.; (iv) there is probably inherent immunity in a certain proportion, but not in measles; (v) the ratio of latent to manifest infections is lower.

We are indebted to Miss M. Kirby for drawing the diagrams in this paper. Towards the expenses of this research a grant was made by the British Medical Association.

The bacterial status of beef carcasses at a commercial abattoir was monitored before and after slaughterline automation. Bacterial counts did not differ significantly overall (P>0·05) between the original manual line and the automated line for either morning or afternoon slaughter. On the manual line counts in the morning were lower than those from carcasses slaughtered in the afternoon, but on the automated line there was no difference between morning and afternoon counts. Due to highly significant line × sample site interaction for both morning and afternoon counts, overall differences among sample sites were not found by analysis of variance. However, principal components analysis revealed a significant shift in bacterial contamination among some sites due to slaughterline changes. The incidence of Enterobacteriaceae increased marginally following automation.