Group B streptococci (GBS) were isolated from bovine bulk milk and from vaginas and throats of antenatal and postnatal women using TKT and rapid GBS media. Sixty-three of 529 (12%) bovine bulk milk samples, 9 of 48 (19%) vaginal and 3 of 48 (6%) throat samples were positive. Both bovine and human beta haemolytic isolates were characterized biochemically and serologically. Pigment production was a characteristic of both human and bovine beta haemolytic isolates. The majority (88%) of human isolates fermented salicin and not lactose and most bovine isolates were either lactose positive/salicin positive (41%) or lactose positive/salicin negative (38%). Human and bovine isolates were 100% and 85% typable respectively. Serotype distribution was similar in the bovine and human populations with serotype la, lc and lll being most common in both. Fermentation of sugars showed major differences between bovine and human isolates but similarity in serotype distribution suggests some genetic relationship.

Persons who develop tuberculosis (TB) may have subtle immune defects that could predispose to other intracellular bacterial infections (ICBIs). We obtained data on TB and five ICBIs (Chlamydia trachomatis, Salmonella spp., Shigella spp., Yersinia spp., Listeria monocytogenes) reported to the Tennessee Department of Health, USA, 2000–2011. Incidence rate ratios (IRRs) comparing ICBIs in persons who developed TB and ICBIs in the Tennessee population, adjusted for age, sex, race and ethnicity were estimated. IRRs were not significantly elevated for all ICBIs combined [IRR 0·87, 95% confidence interval (CI) 0·71–1·06]. C. trachomatis rate was lowest in the year post-TB diagnosis (IRR 0·17, 95% CI 0·04–0·70). More Salmonella infections occurred in extrapulmonary TB compared to pulmonary TB patients (IRR 14·3, 95% CI 1·67–122); however, this appeared to be related to HIV co-infection. TB was not associated with an increased risk of other ICBIs. In fact, fewer C. trachomatis infections occurred after recent TB diagnosis. Reasons for this association, including reduced exposure, protection conferred by anti-TB drugs or macrophage activation by Mycobacterium tuberculosis infection warrant further investigation.

Established methods of recruiting population controls for case–control studies to investigate gastrointestinal disease outbreaks can be time consuming, resulting in delays in identifying the source or vehicle of infection. After an initial evaluation of using online market research panel members as controls in a case–control study to investigate a Salmonella outbreak in 2013, this method was applied in four further studies in the UK between 2014 and 2016. We used data from all five studies and interviews with members of each outbreak control team and market research panel provider to review operational issues, evaluate risk of bias in this approach and consider methods to reduce confounding and bias. The investigators of each outbreak reported likely time and cost savings from using market research controls. There were systematic differences between case and control groups in some studies but no evidence that conclusions on the likely source or vehicle of infection were incorrect. Potential selection biases introduced by using this sampling frame and the low response rate are unclear. Methods that might reduce confounding and some bias should be balanced with concerns for overmatching. Further evaluation of this approach using comparisons with traditional methods and population-based exposure survey data is recommended.

We investigated whether countries with higher coverage of childhood live vaccines [BCG or measles-containing-vaccine (MCV)] have reduced risk of coronavirus disease 2019 (COVID-19)-related mortality, while accounting for known systems differences between countries. In this ecological study of 140 countries using publicly available national-level data, higher vaccine coverage, representing estimated proportion of people vaccinated during the last 14 years, was associated with lower COVID-19 deaths. The associations attenuated for both vaccine variables, and MCV coverage became no longer significant once adjusted for published estimates of the Healthcare access and quality index (HAQI), a validated summary score of healthcare quality indicators. The magnitude of association between BCG coverage and COVID-19 death rate varied according to HAQI, and MCV coverage had little effect on the association between BCG and COVID-19 deaths. While there are associations between live vaccine coverage and COVID-19 outcomes, the vaccine coverage variables themselves were strongly correlated with COVID-19 testing rate, HAQI and life expectancy. This suggests that the population-level associations may be further confounded by differences in structural health systems and policies. Cluster randomised studies of booster vaccines would be ideal to evaluate the efficacy of trained immunity in preventing COVID-19 infections and mortality in vaccinated populations and on community transmission.

The coypu (Myocastor coypus Molina) is an aquatic rodent that has become a widespread pest in the south-east of England. Since the natural habitat of this animal is aquatic, the possibility of infection with leptospires was investigated. Twenty-nine coypu were trapped and examined by serological, histological and cultural methods. Of these, there was serological evidence of infection in seven coypus and Leptospira interrogans var. Wolffii was isolated from a further animal. This appears to be the first report of the isolation of leptospira from a coypu in Great Britain.

Young age, adverse environmental conditions and infectious agents are established risk factors of lower respiratory tract infection (LRTI), whereas pneumococcal conjugate vaccines may be protective. To explore their relative role as predictors of hospitalizations under the continental climate prevailing in the province of Quebec, Canada, an ecological study was performed. Records with a main diagnosis of LRTI in children born during 2007–2010 and observed up to their second-year anniversary were extracted from the provincial hospital administrative database. Respiratory virus surveillance data and statistics on ambient air temperature were obtained. Vaccine use in different birth cohorts was derived from the Quebec City Immunization Registry. Additive and multiplicative Poisson regression models were applied to estimate attributable fractions. Age, month of birth, ambient temperature, and respiratory syncytial virus (RSV), human metapneumovirus (hMPV) and influenza-positive test proportions were significant predictors of LRTI hospitalizations. No substantial differences were observed in cohorts exposed to the 7-valent or 10-valent pneumococcal conjugate vaccines. In the additive model, the fraction of hospitalizations explained by temperature variation was 37%, whereas RSV circulation explained 28%, hMPV 4% and influenza 1%. Complex interplay between biological, environmental and social mechanisms may explain the important role of ambient air temperature in predicting LRTI hospitalization risk in young children.

The overuse of antibiotics and the rapid emergence of antibiotic resistance prompted the launch of an antimicrobial stewardship programme in 2011. This study aimed to investigate the trends and correlations between antibiotic consumption and resistance of Staphylococcus aureus in a tertiary hospital of northwest China from 2010 to 2016. Trends were analysed by linear regression, and correlations were assessed by an autoregressive integrated moving average model. The total consumption of antibiotics halved during the 7-year study period, while the rates of resistance of S. aureus decreased significantly or remained stable; methicillin-resistant S. aureus (MRSA) declined markedly, from 73.3% at the beginning of the study to 41.4% by the end. This latter decrease was significantly correlated with the consumption of several classes of antibiotics. In conclusion, reduction in antibiotic use impacted significantly on resistance rates and contributed to a decline in MRSA prevalence.

This study aimed to determine current seroprevalence of hepatitis A virus (HAV) antibody in subjects aged 0–30 years in Shanghai. A total of 5515 subjects were recruited through random clustering sampling in 2009. Basic clinical and demographic information and records of HAV vaccination were acquired by questionnaire interviews and review of immunization records. Serum samples were collected and tested for anti-HAV IgM and total anti-HAV. The overall seroprevalence of total anti-HAV was 52·9%. Subjects aged 20–24 years had the lowest (34·4%) anti-HAV seropositivity and subjects aged 5–9 years had the highest (74·6%) positivity. Seroprevalence was significantly greater in subjects from suburban areas than in subjects from urban areas. Subjects who had HAV immunizations had significantly greater seropositivity for total anti-HAV. Previous hepatitis A immunization policies had a significant impact on the presence of anti-HAV seroprevalence in a population aged 0–30 years from Shanghai.

Agglutinating antibodies to somatic ‘O’ and flagellar ‘H’ antigens of S. dublin were measured in the serum of 43 pregnant heifers before intravenous or oral infection with S. dublin and in the serum of 21 uninfected control animals. The data from these animals were analysed statistically and a titre of 1/80, to both antigens, has been interpreted as of doubtful significance and a titre of 1/160 to both antigens, has been interpreted as significantly raised. Animals in which fetal infection occurred after challenge by either the intravenous or oral route developed significant increases in ‘H‘O’ titres indicating the value of measuring ‘H’ titres in the diagnosis of S. dublin abortion. In animals which were infected orally and in which infection appeared to be confined to the alimentary tract the ‘H’ titre did not become significantly raised. Lack of correlation between antibody titres and faecal excretion of S. dublin and persistence of infection in carcasses confirms that the serum agglutination test is of no value in detecting latent carriers.

The material on which this enquiry is based consisted of tuberculous tissue, pus, or fluid obtained from the sources specified in Table II, pp. 260–268.

The mathematical function for the horizontal transmission of a pathogen is a driving force of epidemiological models. This paper aims at studying the influence of different transmission functions on a simulated pathogen spread. These functions were chosen in the literature and their biological relevance is discussed. A theoretical SIR (Susceptible–Infectious–Recovered) model was used to study the effect of the function used on simulated results. With a constant total population size, different equilibrium values for the number of infectious (NI) were reached, depending on the transmission function used. With an increasing population size, the transmission functions could be assimilated to either density-dependent (DD), where an equilibrium was obtained, or frequency-dependent (FD), with an exponential increase in NI. An analytical study corroborated the simulated results. As a conclusion, the choice between the different transmission functions, particularly between DD and FD, must be carefully considered for a varying population size.

In low vaccination coverage regions (LVR) in The Netherlands people often reject participation in the National Immunization Programme for religious reasons. During a rubella epidemic in 2004–2005, 32 pregnant women were notified with rubella, and 11 babies were born with defects related to maternal infection. This study presents a cost-utility analysis of a screening and vaccination programme for rubella focusing on three scenarios: (1) screening non-vaccinated pregnant women in LVR; (2) screening all pregnant women in LVR; (3) screening all non-vaccinated pregnant women in The Netherlands (including pregnant first-generation non-Western immigrant women). Cost-utility was estimated over a 16-year period which included two rubella outbreaks. Observed complications from the 2004–2005 epidemic were used to estimate average cost savings and quality-adjusted life-years (QALY) gained. The programme would be cost-effective (€1100/QALY gained) when assuming an acceptability of vaccination of 20% in women belonging to orthodox protestant risk groups.

There are few data on circulatory pro-inflammatory cytokine levels and cytokine gene polymorphisms in H. pylori-positive patients. A cross-sectional study was conducted to examine the effects of H. pylori infection, gastric atrophy, and the IL-8 T-251A polymorphism on plasma IL-8 levels in 98 Japanese adults. Seventy-one subjects were positive for H. pylori infection. The geometric mean of plasma IL-8 concentration was significantly higher in subjects with H. pylori infection than in those without (P=0·001). The development of atrophy was negatively associated with IL-8 levels in the H. pylori-positive subjects, although not significantly. Plasma IL-8 levels in the T/T genotype were associated with H. pylori infection and atrophy status (P=0·016). Our findings suggested that circulating IL-8 levels were associated with H. pylori infection. The effect of H. pylori infection on plasma IL-8 levels was not clearly modified by the IL-8 T-251A polymorphism.

Seven more carriers, all possessing appreciable quantities of Vi agglutinins, are added to those already known.

Vi agglutination tests performed on 2526 inhabitants of the Transvaal, both native and white, showed that 5·3 % had similar quantities of Vi agglutinins.

A fair number of these positive reactors were further examined for the presence of typhoid bacilli in their excreta, but the number of positive findings was very small.

It is argued that there are a large number of typhoid faecal carriers who are such minimal excreters that the typhoid bacilli in their stools escape detection.

We wish to thank Dr T. Lötter, Acting Medical Officer of Health of Pretoria, and his staff, for their kindly help in collecting the material for this paper. Our special thanks are due to Lieut.-Col. H. Nelson, Medical Officer of Health of Pretoria, now on active service, for his never-failing interest in our work which has been such a great encouragement.

1. Antibodies in general are absorbed very slowly from the peritoneal cavity in lower animals, and from the subcutaneous tissues in man and animals. Absorption from the latter is not complete until at least 2—3 days have elapsed.

2. The amount of antibody present at any one time in the general circulation after intraperitoneal or subcutaneous injection is very much less than the amount injected.

3. Clinically, in urgent cases of disease, to inject antibodies subcutaneously is not only to lose 2—3 days' time before the full action can be obtained but to reduce the amount of action that the dose injected can have.

4. By intravenous injection the maximum amount of action is obtained at once.

The whole of the experiments recorded in this paper were made in the Statens Serum-Institut at Copenhagen, where every possible facility was given me for the carrying out of this research. To Dr Thorvald Madsen I desire to express my thanks not only for his unvarying kindliness and courtesy, but also for suggestions and assistance constantly given. I am pleased to have this opportunity of expressing my indebtedness to him.

The main clinical and pathological features of the naturally occurring canine virus hepatitis were reproduced in dogs, using four strains of virus from different parts of the world and by various routes of inoculation. Young puppies seemed to be most susceptible. A kitten was also infected. An unusual type of kerato-conjunctivitis occurred after both intraocular and intraperitoneal injection.

Specific antigen was detected in the blood for short periods at irregular intervals during the acute stages of the illness and up to 6 months after complete clinical recovery.

Specific antibodies were detected in the blood of recovered animals 3 to 10 weeks after the inoculation and 2–6 weeks after the onset of clinical illness.

The four strains of virus were similar in their serological and immunological characters.

Evidence is presented that virus can persist for some months in recovered animals.

Virus was demonstrated in lice collected from affected dogs.

The importance of clinically inapparent infections is stressed.

Cyclospora cayetanensis is an emerging food- and waterborne pathogen that causes cyclosporiasis, a gastrointestinal disease in humans. The parasite is endemic in tropical and subtropical regions; however, its prevalence is largely dependent on environmental factors, such as climate and rainfall patterns. The objective of this paper was to conduct a systematic review and meta-analysis to determine the prevalence of C. cayetanensis in water and to determine if geography, water source and other variables influence this prevalence. A literature search was performed using search terms relating to water and C. cayetanensis in MEDLINE®, CAB Direct, Food Science and Technology Abstracts, Agricola databases and Environmental Science Index. Observational studies published in English after 1979 were eligible. Screening, data extraction and risk-of-bias assessment were performed independently by two reviewers. A multi-level random-effects meta-analysis was completed to determine the prevalence of C. cayetanensis in water and subgroup meta-analyses were performed to explore between-study heterogeneity. The search identified 828 unique articles, and after the screening, 33 articles were included in the review. The pooled prevalence of C. cayetanensis in water was 6.90% [95% confidence interval (CI) 2.25%–13.05%, I2 = 84.38%]. Subgroup meta-analyses revealed significant differences in the prevalence between continents. Additionally, laboratory methods between studies were highly variable and these findings highlight the need for further environmental research on C. cayetanensis in water using detection methods that include PCR and sequencing to accurately identify the organism. The results of this study can be used to help assess the risk of waterborne cyclosporiasis.

We investigated the drug resistance of Mycobacterium tuberculosis isolates from patients with tuberculosis (TB) and HIV, and those diagnosed with only TB in Sichuan, China. TB isolates were obtained from January 2018 to December 2020 and subjected to drug susceptibility testing (DST) to 11 anti-TB drugs and to GeneXpert MTB/RIF testing. The overall proportion of drug-resistant TB (DR-TB) isolates was 32.1% (n = 10 946). HIV testing was not universally available for outpatient TB cases, only 29.5% (3227/10 946) cases had HIV testing results. The observed proportion of multidrug-resistant TB (MDR-TB) isolates was almost double than that of the national level, with approximately 1.5% and 0.1% of the isolates being extensively drug resistant and universally drug resistant, respectively. The proportions of resistant isolates were generally higher in 2018 and 2019 than in 2020. Furthermore, the sensitivities of GeneXpert during 2018–2020 demonstrated a downward trend (80.9, 95% confidence intervals (CI) 76.8–85.0; 80.2, 95% CI 76.4–84.1 and 75.4, 95% CI 70.7–80.2, respectively). Approximately 69.0% (7557/10 946) of the TB cases with DST results were subjected to GeneXpert detection. Overall, the DR-TB status and the use of GeneXpert in Sichuan have improved, but DR-TB challenges remain. HIV testing for all TB cases is recommended.

Studies were made of a 14-room isolation ward in which the bedrooms were provided with individual ventilation units to provide a slight positive pressure within the rooms. Airborne staphylococci were detected with sedimentation plates.

The median count of Staphylococcus aureus in the occupied bedrooms was 4·6 col. per 14 cm. plate exposed for 24 hr. or 13 col./m.2 hr. When the air count was high virtually all the staphylococci proved to be of the phage type harboured by the patient in the room; with low counts a substantial proportion were apparently derived from patients in other rooms.

The apparent rate of acquisition of S. aureus in the nose of the patients was between 2·7 and 4·2 per 100 patient weeks at risk. This is substantially lower than has commonly been observed in open wards.

We are very graetful to Miss M. A. Adams, Sister in charge of the Almroth-Wright isolation Ward, and all her staff for all their help and co-operation during this study, which was supported by funds provided to St Mary's Hospital by the Ministry of Health for clinical research.

The reconstruction of the ward was designed by Mr A. Stableford, Group Engineer to St Mary's Hospital; the ventilation units were designed and supplied by White Bays and White Ltd., London.

In a recent survey of trimethoprim resistance. 357 Gram-negative aerobic organisms were isolated from healthy volunteers from rural and urban populations in South Africa. Trimethoprim resistance did not transfer to an Escherichia coli J62–2 recipient strain by conjugation in a liquid mating in 161 (45·1%) of the isolates. These isolates which did not transfer their resistance were probed with intragenic oligonucleotide probes for the types Ia. Ib. IIIa. V. VI. VII. VIII. IX. X and XII dihydrofolate reductase genes. Contrary to all previous data, the most prevalent dihydrofolate reductase gene in this group of non-transferable isolates which hybridized, was the type VII (38%) followed by the type Ia (25%). Ib (12%). V (1·7%) and VIII (1·2%). None of the strains hybridized to the types IIIa. VI. XI. X and the XII dihydrofolate reductase probes. Southern blots of plasmid and chromosomal DNA from selective isolates revealed that the type VII dihydrofolate reductase genes were located on the chromosome and were associated with the integrase gene of Tn21. However, the type Ib and V dihydrofolate reductase genes were all found on plasmids which could not be mobilized. The type Ia dihydrofolate reductase genes were found on both non-transferable plasmids and on the chromosome. The nature of the genetic structures associated with a dihydrofolate reductase gene strongly affects the means of spread of the gene in a population.