1. Cultures of tubercle bacilli were obtained from 204 cases of lupus.

2. According to their cultural characters the strains could be divided into two main groups, one containing 102 strains with the characters of human tubercle bacilli and the other containing 102 strains with the characters of bovine tubercle bacilli.

3. Virulence tests were carried out on a large number of animals, and in one instance over 100 animals were used for testing strains from a particular case.

4. Of the 102 culturally human strains 41 were highly virulent for the guineapig, and for the monkey when this was tested, producing progressive and rapidly fatal tuberculosis. The remaining 61 strains (59.8%) showed varying degrees of attenuation.

5. Of the 102 culturally bovine strains 34 were highly virulent for all the animals tested, producing in them severe and rapidly fatal general tuberculosis identical with that set up by standard bovine bacilli. The remaining 68 (66.7%) were of lower virulence for the rabbit, and for the calf and goat when these animals were tested, than standard bovine strains, but they all produced in one, two, or three of these species more extensive tuberculosis than human bacilli. For the guineapig, and for the monkey when tested, these strains fell below the virulence of standard bovine strains, except for a few whose virulence was only slightly lowered for the rabbit.

Methicillin-resistant Staphylococcus aureus (MRSA) infection is known to increase in-hospital mortality, but little is known about its association with long-term health. Two hundred and thirty-seven deaths occurred among 707 patients with MRSA infection at the time of hospitalization and/or nasal colonization followed for almost 4 years after discharge from the Atlanta Veterans Affairs Medical Center, USA. The crude mortality rate in patients with an infection and colonization (23·57/100 person-years) was significantly higher than the rate in patients with only colonization (15·67/100 person-years, P = 0·037). MRSA infection, hospitalization within past 6 months, and histories of cancer or haemodialysis were independent risk factors. Adjusted mortality rates in patients with infection were almost twice as high compared to patients who were only colonized: patients infected and colonized [hazard ratio (HR) 1·93, 95% confidence interval (CI) 1·31–2·84]; patients infected but not colonized (HR 1·96, 95% CI 1·22–3·17). Surviving MRSA infection adversely affects long-term mortality, underscoring the importance of infection control in healthcare settings.

It is greatly to be desired that the causes of the decline of tuberculosis, which has been so striking a feature in the history of that disease in recent times, should be clearly ascertained; for only through an understanding of their nature and relative importance can our efforts to accelerate that decline hope to succeed.

Normally, only one isolate of Listeria monocytogenes from a case of listeriosis is subjected to characterization. Here we show that two isolates from different sites of the body were not the same strain. Such a phenomenon may not have any clinical relevance, although it may confuse the epidemiologist trying to match infection source with infection target.

The occurrence of epidemics of vaccine-preventable diseases, and the immunization coverage required to prevent them, is affected by the presence of households and heterogeneity in the community. We consider a community where individuals live in households and are of different types, according to infectivity and/or susceptibility to infection. We describe a method for computing the critical immunization coverage to prevent epidemics in such communities and discuss the effectiveness of immunization strategies. In a heterogeneous community where individuals live in households several immunization strategies are possible and we examine strategies targeting households, randomly selected individuals, or groups with highly intense transmission, such as school children. We compare estimates of the critical immunization coverage if we assume that disease is spread solely by random mixing with estimates which result if we assume the effects of the household structure. Estimates made under these two sets of assumptions differ. The results provide insights into the community effects of vaccination, and the household structure of the community should be taken into account when designing immunization policies.

1. The experimental derivation of a mucoid form of B. paratyphosus B is described.

2. This form, though at one stage non-motile, agreed closely with the “capsulated mucoid forms” of paratyphoid B, isolated by W. Fletcher from two chronic “carrier” cases.

3. The mucoid paratyphoid B was highly dys-agglutinable, and it would not on serological examination be identified as a paratyphoid B.

4. Its colonies were also entirely unlike colonies of paratyphoid B, being large, slimy, and usually dome-shaped, though at other stages of their metamorphosis they presented either an umbilication, or a nipple-like elevation in the centre.

5. The mucoid bacillus possessed the distinctive sugar reactions of paratyphoid B.

6. On suitable manipulation it reverted to the ordinary form.

Resistance to beta-lactam antimicrobials caused by extended-spectrum beta-lactamase (ESBL)-producing organisms is a global health concern. The objectives of this study were to (1) summarise the prevalence of potential ESBL-producing Escherichia coli (ESBL-EC) and Salmonella spp. (ESBL-SA) isolates from agrifood and human sources in Canada from 2012 to 2017, and (2) describe the distribution of ESBL genotypes among these isolates. All data were obtained from the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS). CIPARS analysed samples for the presence of ESBLs through phenotypic classification and identified beta-lactamase genes (blaTEM, blaSHV, blaCTX, blaOXA, blaCMY−2) using polymerase chain reaction (PCR) and whole genome sequencing (WGS). The prevalence of PCR-confirmed ESBL-EC in agrifood samples ranged from 0.5% to 3% across the surveillance years, and was detected most frequently in samples from broiler chicken farms. The overall prevalence of PCR-confirmed ESBL-SA varied between 1% and 4% between 2012 and 2017, and was most frequently detected in clinical isolates from domestic cattle. The TEM-CMY2 gene combination was the most frequently detected genotype for both ESBL-EC and ESBL-SA. The data suggest that the prevalence of ESBL-EC and ESBL-SA in Canada was low (i.e. <5%), but ongoing surveillance is needed to detect emerging or changing trends.

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.

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.

Campylobacter jejuni isolates of human, canine, feline, bovine and poultry origin were investigated for their genomic diversity using O-antigen typing (n = 271), SmaI (n = 158) and XhoI (n = 158) macrorestriction analysis and ERIC–PCR (n = 107). The O-antigens O[ratio ]1/44, O[ratio ]2, O[ratio ]4 complex, O[ratio ]37, O[ratio ]40 were identified and 53.7% of the human and 56.1% of the animal strains were typable with the available antisera. Two ERIC–PCR pattern groups were generated representing human and animal strains as well as those exclusively of animal origin. XhoI macrorestriction analysis also distinguished ‘human’ and ‘non-human’ strain clusters, but by SmaI restriction mainly serotype-associated clusters were found. In conclusion, genomic differences may occur between ‘human’ and ‘non-human’ strains and this may reflect their potential to overcome the barrier from animals to humans.

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.

Over a 2-year period, 25 families comprising of 181 individuals of all ages were longitudinally observed for the excretion of Campylobacter species. Faecal samples were taken from all persons with diarrhoea. Specimens were also taken from apparently healthy individuals and from domestic animals living within the confines of the study families at monthly intervals.

The overall diarrhoea attack rate was 19 episodes per 100 person-years with peak incidence in the 1- to 4-year-old age group (76/100 person-years). Eight (11·5%) of the total episodes were campylobacter-associated and the overall rate of campylobacter positive diarrhoeal episodes were 2·2 per 100 person-years. Of the 1002 stool samples from healthy individuals 32 (3·2/100 samples) were positive for campylobacter. The organism was most frequently isolated from children under 1 year of age both during diarrhoeal episodes (11·5 per 100 person-years) and non-diarrhoeal (11·1 per 100 samples). Multiple infections in a family were rare. In 19·4% of the occasions one or more animals were campylobacter positive. However, only in 7·7% of these occasions was a human infection recorded within 1 month after the animal was found to be positive.

The study showed that the epidemiology of campylobacteriosis in this community was distinct compared to that observed in developed countries.

A year-long community-based study of diarrhoeal diseases was conducted in Canto Grande, a periurban community in Lima, Peru. In 109 (34%) houses out of 323 that were visited, at least one individual was detected with shigellosis. The frequency of the 161 shigella isolates obtained was as follows: 117 S. flexneri (73%), 21 S. boydii (13%), 15 S. dysenteriae (9%), and 8 S. sonnei (5%). Using a non-radioactive ipaH gene probe as a molecular epidemiological tool, a total of 41 S. flexneri strains were shown to be distributed in 25 intra-family comparisons by pairs (icp). Further subdivision, based on a comparison of the serotype, plasmid profile, antibiotic resistances and ipaH hybridization patterns indicated that Group I, with 11 icp (44%), had strains that were identical, Group II with 8 icp (32%), had strains that were different and Group III with 6 icp (24%), had strains with the same serotype and identical ipaH profiles but with differences in other markers. This data indicates that a diversity of shigella clones circulated in this community resulting from both clonal spread and horizontal transfer of genetic elements. Furthermore, ipaH profiling of isolates can be used not only to differentiate between closely related shigella strains but also with other parameters, help to understand the dynamics of the generation of new clones of pathogenic bacteria.

Bacteriocin production (P)-typing of 75 M-type 49 group-A streptococci obtained from a variety of epidemiological incidents in different countries gave no evidence of production under the usual aerobic test conditions. However, with anaerobic incubation, 28% of the strains gave a pattern of inhibitory activity against the indicator strains which was indistinguishable from that previously attributed to the bacteriocin, streptococcin A-FF22 (SA-FF22). Isolation and partial purification of the M type 49 bacteriocin (SA-M49) by freeze–thaw elution from anaerobically grown lawn cultures, followed by ammonium sulphate precipitation and Sephadex chromatography, showed the activity to be associated with a heat-stable proteinaceous molecule of molecular weight approximately 8000 – properties similar to those of SA-FF22. SA-FF22 and SA-M49 were found to have identical inhibitory spectra including immunity of the producer strains to the inhibitory activity of both the homologous and heterologous bacteriocin preparations. SA-M49 production occurred in some strains of phage subtypes II, III and provisional VI and. since it was a consistent property for all isolates from single outbreaks of infection, it provides a means of discriminating between strains of each of these three phage subtypes. There was no evidence of any increased incidence of SA-M49 production in M-type 49 strains associated with nephritic sequelae

This prospective, multicentre study was conducted during 2–30 April 2001 in the internal medicine/infectious diseases services in France and included data from 1858 hepatitis C virus (HCV)-infected patients, half of whom were HIV co-infected. The aims were to outline the type of pre-therapeutic evaluation of HCV infection performed (HCV RNA, genotype, liver biopsy); determine the proportion and characteristics of patients receiving antiviral treatment; and determine if any changes in these parameters had occurred between 1995 and 2001. Patients whom had a complete pre-therapeutic evaluation (39%, 709/1834) and received antiviral treatment (38%, 690/1830) were more likely to have abnormal liver biochemistry, cirrhosis and cryoglobulinaemia (P<0·001). Injecting drug users and HIV-co-infected patients were less likely to have a complete pre-therapeutic evaluation or receive antiviral treatment (P<0·001). A complete pre-therapeutic evaluation was more often performed in 2001 than in 1995 (39% vs. 6%, P<0·001), including qualitative HCV RNA testing (91% vs. 68%, P<0·001), genotyping (59% vs. 7%, P<0·001) and a liver biopsy (60% vs. 29%, P<0·001). The frequency of anti-HCV treatment approximately doubled between 1995 and 2001 (20% vs. 38%, P<0·001). Although adherence to consensus recommendations regarding pre-therapeutic evaluation is not ideal, a substantial improvement has occurred since 1995. Nevertheless, means of increasing the availability of antiviral therapies, particularly for patients with HIV co-infection or injecting drug use, require further study.

An analysis has been made of the records of 5290 attendances at the Common Cold Research Unit, Salisbury, during the years 1946 to 1957. Materials prepared from the nasal washings of persons suffering from colds were administered to 993 volunteers, of whom 386 (38·9 %) showed definite evidence of infection within a few days. The attack rate of these experimentally induced colds was lower during the months October to March than from April to September. The difference was statistically significant as regards male but not as regards female volunteers.

Six strains of virus were propagated by passage from volunteer to volunteer, in one instance up to the eighth serial transfer from the original material, without apparent loss of pathogenic properties. Comparison of the clinical effects of these strains, and of a number of miscellaneous strains, revealed several differences which were minor in character but, statistically, highly significant. These comprised differences in attack rate, severity, incubation period, duration and relative frequency of symptoms, which could not be ascribed to seasonal or other influences.

It was concluded that the observed variations in the clinical pattern of the experimentally induced colds were attributable to qualitative differences in the strains of virus used.

I wish to thank Sir Christopher Andrewes, F.R.S., for his unfailing help and encouragement at every stage of this investigation and all my colleagues at the Common Cold Research Unit for much useful comment and discussion. I am indebted to the Statistics Department of the Ministry of Labour and National Service for processing the records and to Mr R. G. Carpenter for assistance with some of the statistical analyses.

The joints of rabbits are predilection sites of disease in chronic avian infections and are nearly always found affected in rabbits which have lived longer than 3–4 months after an intravenous or subcutaneous inoculation of fully virulent avian strains. Highly attenuated avian strains, namely, those which have ceased to be infective for fowls, also give rise to joint disease in rabbits when injected intravenously; for example, twelve rabbits which lived over 5 months after intravenous inoculation of 2·5–10·0 mg. of attenuated avian strains all showed joint tuberculosis, and in eleven of these the joints were the only affected parts (Griffith, 1925).

The work described in this paper was commenced in 1926 in order to demonstrate whether or no infections with the M. catarrhalis afford positive reactions with gonococcal antigens. It had already been shown that an antigen of M. catarrhalis might react with the sera from gonococcal infections. Later it was decided to investigate aberrant forms of M. catarrhalis and allied organisms and also to test whether sera which react very strongly to the Wassermann reaction might also react non-specifically to the Gonococcal Complement Fixation test, possibly to such a degree as to detract from the value of the latter. Such a non-specific reaction might be of the nature of a group fixation (the Wassermann being not anti-spirochactal but probably anti-lipoidal), or to adventitious substances introduced in the preparation of the gonococcal extracts from cultures derived from patients with secondary syphilis.

Many writers having observed that cases of acute rheumatism are not distributed evenly throughout the year, much study has been devoted to the possible relationship between these variations and meteorological conditions.

A high incidence of resistance to trimethoprim has been shown in the normal faecal flora in a population in south India. The dihydrofolate reductase (dhfr) genes mediating transferable resistance to trimethoprim have been identified. Unusually, in this study, the dhfr V was shown to be the predominant resistance gene (dhfr V 50% of tranaconjugants, dhfr Ia 30%), the dhfr Ib was also detected being distinguished from the dhfr V by an oligo-probe. However, when non-transferable resistance was considered, the dhfr Ia was the most prevalent of the dhfrs identified. All those plasmids harbouring the dhfr Ia were shown to possess Tn7. All the plasmids that probed positive for the dhfr V and the dhfr Ib were shown to be associated with the integrase of the Tn21-like transposons, but 8 of the dhfr V genes were not associated with the Tn21 resolvase. The dhfr IV was shown to be present in all seven plasmids that produced low level trimethoprim-resistance. The dhfr V. first characterized in Sri Lanka, would seem to have a local distribution in this region of Asia but is distinguishable from the dhfr Ib only by the use of an oligo-probe.