Operating in ultraclean air and the prophylactic use of antibiotics have been found to reduce the incidence of joint sepsis confirmed at re-operation, after total hip or knee-joint replacement. The reduction was about 2-fold when operations were done in ultraclean air, 4·5-fold when body-exhaust suits also were worn, and about 3- to 4-fold when antibiotics had been given prophylactically. The effects of ultraclean air and antibiotics were additive. Wound sepsis recognized during post-operative hospital stay was, however, reduced by these measures only when it had been classed as major wound sepsis. This was reported after 2·3% of operations done without antibiotic cover in conventionally ventilated operating rooms.

Joint sepsis was much more frequent after wound infection and especially after major wound sepsis, although most cases of joint sepsis were not preceded by recognized wound sepsis. This was particularly noticeable after major wound sepsis associated with Staphylococcus aureus; after 37 such infections the same species was subsequently found in the septic joint of 11 patients. The sources of wound colonization with Staph. aureus, when this was not followed by joint sepsis, appeared to differ widely from those where joint sepsis occurred later. Operating-room sources could bo found for most of the latter and the risk of infection appeared to be similar with respect to any carrier in the operating room whether a member of the operating team or tho patient. For wound colonization that was not followed by joint sepsis, operating-room sources could only be inferred for fewer than half and of these more than one half appeared to be related to strains carried by the patient at the time of operation.

During tho follow-up period, which averaged about 2¼ years with a maximum of four years, there were, in addition to the 86 instances of deep joint sepsis confirmed at re-operation, 85 instances in which sepsis in the joint was suspected during this period but was not confirmed, because re-operation on the joint was not done. The incidence of suspected joint sepsis was, like that of confirmed joint sepsis, less after operations done in ultraclean air: 1/2·5, or with prophylactic antibiotics, 1/2·3

Although re-operation was more frequent on tho knee-joint than on the hip, and pain after the initial operation was more frequent after knee operations, there was no evidence that this was the result of any increased risk of infection.

There was some indication of an increased risk of joint sepsis and of major wound sepsis, after operations on patients with rheumatoid arthritis compared with other diagnoses. The increase could have been as much as twofold but, because of the small numbers involved, the statistical limitations of the study render these differences only marginally significant.

When wound washout samples had been obtained from the surgical wound after the insertion of the prosthesis the risk of subsequent joint sepsis was found to be considerably greater for those patients from whose wounds larger numbers of bateria were isolated than from those of other patients at the same hospital.

We describe here an examination of the validity of molecular types of Campylobacter jejuni as defined by separation of SmaI-digested DNA using pulsed-field gel electrophoresis (PFGE), recently suggested as part of a molecular subtyping scheme. Thirty-four Danish strains from humans, water, poultry and cattle were assigned to one of six SmaI ‘profile groups’ (PGs), with two additional strains included as genotypically distinct controls. The interstrain relationships were reexamined by PFGE of SalI, KpnI and BamHI-digested DNA, and also by serotyping with heat-stable antigens. All outbreak-related strains were indistinguishable by all criteria, as were two sets of two randomly-isolated human strains. Two groups of indistinguishable isolates contained randomly isolated strains from more than one source (poultry, humans and/or cattle), a finding with significant epidemiological connotations. All ‘genetically identical’ strains belonged to the same serotype, whereas genetic differences were detected between strains assigned to the same SmaI PG but differing in serotype. We conclude that PFGE-based genetic fingerprinting can yield invaluable data for epidemiological studies of sporadic C. jejuni infection, but that results based on one restriction site polymorphism must be checked with another enzyme.

The aim was to establish the prevalence of large pericardial effusions in the Western Cape Province of South Africa, and to determine the incidence of various types of effusions. A total of 233 patients presented with large pericardial effusions. Each patient underwent tests for HIV, sputum smear and culture, blood culture, blood biochemistry and serological testing. Tuberculous pericardial effusions were diagnosed according to pre-determined criteria. Eighty-four patients (36·1%) were found to be HIV positive; 81 of these (96·4%) had tuberculous pericarditis. More than 65% of the study population was aged between 15 and 39 years. The prevalence of HIV amongst unemployed individuals was 49·0% compared to 30·0% amongst employed individuals. Tuberculous pericarditis was the most common cause of pericardial effusions (69·5%, n=162). It was concluded that tuberculosis (TB) is a leading cause of pericarditis in this province of South Africa. The prevalence of TB confounded by HIV co-infection is steadily increasing, burdening the health-care facilities.

Cattle are considered to be a reservoir host of Escherichia coli O157[ratio ]H7 and contaminated foods of bovine origin are important vehicles of human infection. In this study, the susceptibility of calves to experimental E. coli O157[ratio ]H7 infection following low oral exposures was determined. Two of 17 calves exposed to very low (<300 c.f.u.) doses, and 3 of 4 calves exposed to low (<10000 c.f.u.) doses, subsequently excreted the challenge strains in their faeces. All calves (n = 12) sharing isolation rooms with calves that excreted the challenge strain in their faeces similarly began faecal excretion of the same strains within 21 days or less. The identity between the challenge strains and the strains excreted in calf faeces was confirmed by restriction digestion electrophoretic patterns using pulsed field gel electrophoresis. Calves shed E. coli O157[ratio ]H7 in their faeces after very low dose exposures at concentrations ranging from <30 to >107 c.f.u./g, and for durations similar to the values previously reported for calves challenged by larger doses. The susceptibility of calves to infection following very low exposures or direct contact with infected calves has important implications for programmes for pre-harvest control of this agent.

Bivalve molluscs, (cockles, mussels, scallops and oysters) were examined according to EC shellfish bed classification regulations for faecal coliforms, Escherichia coli and salmonella, and for coliforms and campylobacter which are not specified by these regulations. Salmonella serotypes were detected in 8% of 433 molluscs. Seven salmonella isolations (2%) were made from category A beds, nominally suitable for immediate consumption according to E. coli counts. A higher percentage of salmonella isolates (6%) was detected in shellfish which require relaying or depuration prior to eating. In another survey, thermophilic Campylobacter spp. were found in 42% of 380 shellfish. These findings show that shellfish bed classification on the basis of indicator organisms alone is not sufficient to assure the absence of bacterial, and no doubt viral, pathogens. Depuration and end product specifications which require the absence of salmonellae are an essential part of these regulations. Microbiologists may wish to consider whether tests for pathogens such as salmonella and campylobacter should be included when determining the suitability of shellfish for human consumption.

A large-volume sampler was used to recover virus excreted as aerosol by cattle, sheep and pigs infected with foot-and-mouth disease. Pigs were found to excrete virus to a maximum of 104.7 ID 50 per animal per hour and sheep and cattle to a maximum of 103.2 ID 50. Excretion from pigs totalled 106 ID 50 per animal over 5 days and from cattle and sheep 3 x 104 ID 50 per animal over 4 days. Maximum recovery occurred 41 hr. after infection in pigs and cattle when lesions had generalized and 17 hr. after infection in sheep before lesions had been observed. Sampling in a multistage liquid impinger showed that 65–71% of virus was excreted as an aerosol of size > 6 μ, 19–24% 3–6 μ and 10–11% less than 3 μ. The site of production of virus excreted as aerosol is suggested to be the upper respiratory tract. Under conditions of relative humidity greater than 70% and at low temperatures, survival of virus to a distance of 100 km. is likely to occur and because of the minute respiratory volume the aerosol would be sampled more efficiently by cattle than pigs or sheep and by large animals than by small. These findings are discussed in relation to spread of virus in the field.

Mr Dave Allen and Massey-Ferguson Ltd. are thanked for their generous donations, with which the large-volume sampler was purchased. We are grateful to Dr C. E. Gordon Smith, Mr G. J. Harper and Dr K. P. Norris of the Microbiological Research Establishment, Porton, for advice and help and for the loan of the multistage liquid impinger. The technical assistance of N. H. Cheale and C. W. Hawkins is gratefully acknowledged.

The age-specific immunity to human parvovirus infection was estimated in Victoria, Australia using prospectively collected samples from the Royal Children's Hospital, the Royal Women's Hospital and the Australian Red Cross Blood Service and from sera stored at the Victorian Infectious Diseases Reference Laboratory (VIDRL). All testing was performed at VIDRL using a commercial enzyme-linked immunosorbent assay (Biotrin). Of the 824 sera tested, 28% of those drawn from people aged 0–9 years contained protective antibodies to human parvovirus. This rose to 51% in the next decade of life. There was then a slow rise to about 78% immunity over 50 years of age. An analysis of all requests for parvovirus serology at VIDRL from 1992 to 1998 suggested that parvovirus tended to occur in 4-year cycles, with 2 epidemic years followed by 2 endemic years. A review of published reports of parvovirus immunity suggested that parvovirus infection may be more common, with a correspondingly higher proportion of the community immune, in temperate as opposed to tropical countries.

Campylobacter infection has one of the highest rates of all the notifiable diseases in Australia, with a peak in children aged 0–35 months. A matched case-control study was conducted to investigate risk factors for campylobacter infection for children in this age group. Eighty-one cases and 144 controls were enrolled in the study that was conducted between 24 January 1996 and 21 January 1997. The following risk factors were found to be independently associated with illness: ownership of pet puppies (adjusted odds ratio [OR] 16·58, 95% confidence interval [CI] 3·73–73·65) and pet chickens (OR 11·80, CI 1·37–101·75), and consumption of mayonnaise (OR 4·13, CI 1·61–10·59). We propose that children aged less than 3 years are at risk of campylobacter infection if residing in a household which has puppies or chickens as pets.

Chickens in groups of 40 were infected orally with a nalidixic acid-resistant mutant of Salmonella typhimurium and then fed continuously on diets containing ampicillin, chloramphenicol, furazolidone, neomycin, oxytetracycline, polymixin, spectinomycin, streptomycin or a mixture of trimethoprim and sulphadiazine. The amount of S. typhimurium excreted in their faeces was estimated at intervals by culture on brilliant green agar containing sodium nalidixate, both direct and after enrichment in selenite broth; the amount of Escherichia coli excreted was estimated by culture on MacConkey agar. The feeding of diets containing 500 mg./kg. of ampicillin, furazolidone, neomycin, polymixin, spectinomycin or streptomycin or 100 mg./kg. of trimethoprim and 500 mg./kg. of sulphadiazine for 46 days reduced to a varying degree the amount of S. typhimurium and E. coli excreted, the greatest reduction in S. typhimurium being brought about by the last treatment. The effect was less obvious when the concentration of the antibiotics in the food was decreased fivefold. An important reason for the very limited effect of some of the antibiotics was the emergence of antibiotic-resistant populations of S. typhimurium and E. coli. High concentrations of antibiotic-resistant organisms also arose in the faeces of the chickens fed diets containing tetracyclines and chloramphenicol, treatments which had no apparent effect on the amount of S. typhimurium and E. coli excreted. Much of the antibiotic resistance encountered was determined by R factors, a particular R factor usually being found in the E. coli populations of individual chickens before it was found in their S. typhimurium populations. No S. typhimurium or E. coli were isolated that possessed R factors determining resistance to polymixin, furazolidone or trimethoprim. No S. typhimurium or E. coli were isolated that were polymixin-resistant and no S. typhimurium that were furazolidone-resistant. The few trimethoprim-resistant S. typhimurium isolated were thymine-dependent.

The feeding of diets containing the higher concentrations of trimethoprim/sulphadiazine, neomycin, furazolidone or ampicillin for 9 days reduced the amount of S. typhimurium excreted. After the withdrawal of these diets, the amount of S. typhimurium excreted increased to the numbers found in chickens given ordinary diets throughout; the chickens that had been given trimethoprim/sulphadiazine or furazolidone did not remain faecal excreters of S. typhimurium longer than the chickens that had been given ordinary diets. Similar results were obtained with trimethoprim/sulphadiazine when the start of the 9-day treatment period was delayed for an extra 9 days or when it was extended to 18 days.

Transferable chloramphenicol resistance has become common in the typhoid bacillus in countries such as Mexico, India, Vietnam and Thailand. Situations such as this, and others analogous to it in many parts of the world, are the result of the long-term indiscriminate use of chloramphenicol and other antibiotics in the affected areas. They can be rectified only by more rational antibiotic usage.

The epidemic of type 2 diabetes in the United States prompted us to explore the association between diabetes and tuberculosis (TB) on the South Texas–Mexico border, in a large population of mostly non-hospitalized TB patients. We examined 6 years of retrospective data from all TB patients (n=5049) in South Texas and northeastern Mexico and found diabetes self-reported by 27·8% of Texan and 17·8% of Mexican TB patients, significantly exceeding national self-reported diabetes rates for both countries. Diabetes comorbidity substantially exceeded that of HIV/AIDS. Patients with TB and diabetes were older, more likely to have haemoptysis, pulmonary cavitations, be smear positive at diagnosis, and remain positive at the end of the first (Texas) or second (Mexico) month of treatment. The impact of type 2 diabetes on TB is underappreciated, and in the light of its epidemic status in many countries, it should be actively considered by TB control programmes, particularly in older patients.

Although contamination of food can occur at any point from farm to table, restaurant food workers are a common source of foodborne illness. We describe the characteristics of restaurant-associated foodborne disease outbreaks and explore the role of food workers by analysing outbreaks associated with restaurants from 1998 to 2013 reported to the Centers for Disease Control and Prevention's Foodborne Disease Outbreak Surveillance System. We identified 9788 restaurant-associated outbreaks. The median annual number of outbreaks was 620 (interquartile range 618–629). In 3072 outbreaks with a single confirmed aetiology reported, norovirus caused the largest number of outbreaks (1425, 46%). Of outbreaks with a single food reported and a confirmed aetiology, fish (254 outbreaks, 34%) was most commonly implicated, and these outbreaks were commonly caused by scombroid toxin (219 outbreaks, 86% of fish outbreaks). Most outbreaks (79%) occurred at sit-down establishments. The most commonly reported contributing factors were those related to food handling and preparation practices in the restaurant (2955 outbreaks, 61%). Food workers contributed to 2415 (25%) outbreaks. Knowledge of the foods, aetiologies, and contributing factors that result in foodborne disease restaurant outbreaks can help guide efforts to prevent foodborne illness.

A simple cubed diet is described, completely adequate to sustain rapid growth and intensive reproduction in mice and rats.

Changes in Helicobacter pylori seroprevalence were studied determining IgG and IgA antibodies of 408 randomly selected adults aged 15–74 years living in Vammala, Finland in 1973 and of 504 similarly selected subjects in 1994. Seroprevalence increased by age at both time points. The age-adjusted seroprevalence rate was clearly lower in 1994 than in 1973 (31 vs. 56%, P=0·001). Paired serum samples of 224 subjects collected in 1973 and 1994 showed that the antibody status remained unaltered in 92%; 4% seroconverted and 4% seroreverted within the 21 years. The decrease in the seroprevalence rate in the population and the persistence of individual antibody status over two decades support a difference in H. pylori infection rates among birth cohorts over time rather than continuous acquisition of new infections with advancing age. Thus the risk of helicobacter infection in Vammala, Finland has been highest in childhood and continuously decreased at least for the last five decades.

Anecdotal evidence suggests that the prevalence of both scabies and head lice is increasing and also that both conditions are becoming refractory to pesticide treatment. Using information obtained from the Office of National Statistics, Royal College of General Practitioners Weekly Returns Service, Department of Health, local surveys of school children from Bristol and drug sales of insecticides, we have confirmed that there has been a rise in the prevalence of both conditions. We have shown that scabies is significantly more prevalent in urbanized areas (P<0·00001), north of the country (P<0·000001), in children and women (P<0·000001) and commoner in the winter compared to the summer. Scabies was also shown to have a cyclical rise in incidence roughly every 20 years. Head lice were shown to be significantly more prevalent in children and mothers (P<0·000001) though both conditions were seen in all age groups. Head lice were also less common during the summer. Host behaviour patterns, asymptomatic carriage, drug resistance and tourism from countries or districts with a higher incidence may be important factors in the currently high prevalence of both scabies and head lice.

The distribution of the Escherichia coli attaching and effacing (eae) gene in strains of verotoxin-producing E. coli (VTEC) isolated from cattle and humans was studied. The majority of strains isolated from humans with bloody diarrhoea or HUS and cattle with severe diarrhoea were eae. positive (82 and 83% respectively). In contrast. 59% of VTEC isolated from asymptomatic cattle were eae negative and of the remaining 41 % that were eae positive, the majority were serotype O157.H7. The nucleotide sequence of the 3′ end of the eae gene of enteropathogenic E. coli (EPEC) of serotype O55.H7 was found to be almost identical to that of serotype O157. H7. Specific primers are described which detect the eae sequences of VTEC serotypes O157.H7, 0157.H−, and EPEC serotypes O55.H7 and O55.H−. The nucleotide sequence of the 3′ end of the eae gene of serotype O111.H8 differed significantly from that of O157.H7. Primers were developed to specifically identify the eae sequences of VTEC serotypes O111. H− and O111.H8. We conclude that whereas the majority of VTEC associated with disease in cattle and humans possess the eae gene, the gene itself may not be necessary to produce haemorrhagic colitis and HUS. Sequence heterogeneity in the 3′ end of eae alleles of VTEC permits specific identification of subsets of these organisms.

This study compares the seasonality of rotavirus diarrhoeal hospital admissions and its relationship to climatic factors across three Australian cities. Weekly admission of rotavirus diarrhoea (1993–2003) in children aged <5 years and weekly average temperature and relative humidity for each city were modelled using a log-linear model with a cubic trend and season. Interactions were included to test for differences in the effect of temperature and humidity between seasons and between cities. Admissions of rotavirus diarrhoea peaked in winter and spring and were lowest in summer. Higher temperature and humidity in the previous week were associated with a decrease in rotavirus diarrhoeal admissions in three cities. The effects of both temperature and humidity on rotavirus admissions in Brisbane differed across seasons. Strategies to combat outbreaks of rotavirus diarrhoea should take climatic factors and seasonal effects into consideration to plan for the excess seasonal hospital admissions.

We conducted a seroprevalence survey in Belgium, Finland, England & Wales, Italy and Poland on 13 449 serum samples broadly representative in terms of geography and age. Samples were tested for the presence of immunoglobulin G antibody using an enzyme immunoassay. The age-specific risk of infection was estimated using parametric and non-parametric statistical modelling. The age-specific risk in all five countries was highest in children aged 7–9 years and lower in adults. The average proportion of women of child-bearing age susceptible to parvovirus B19 infection and the risk of a pregnant women acquiring B19 infection during pregnancy was estimated to be 26% and 0·61% in Belgium, 38% and 0·69% in England & Wales, 43·5% and 1·24% in Finland, 39·9% and 0·92% in Italy and 36·8% and 1·58% in Poland, respectively. Our study indicates substantial epidemiological differences in Europe regarding parvovirus B19 infection.

In December 2019, cases of severe coronavirus 2019 (COVID-19) infection rapidly progressed to acute respiratory failure. This study aims to assess the association between the neutrophil-to-lymphocyte ratio (NLR) and the incidence of severe COVID-19 infection. A retrospective cohort study was conducted on 210 patients with COVID-19 infection who were admitted to the Central Hospital of Wuhan from 27 January 2020 to 9 March 2020. Peripheral blood samples were collected and examined for lymphocyte subsets by flow cytometry. Associations between tertiles of NLR and the incidence of severe illness were analysed by logistic regression.

Of the 210 patients with COVID-19, 87 were diagnosed as severe cases. The mean NLR of the severe group was higher than that of the mild group (6.6 vs. 3.3, P < 0.001). The highest tertile of NLR (5.1–19.7) exhibited a 5.9-fold (95% CI 1.3–28.5) increased incidence of severity relative to that of the lowest tertile (0.6–2.5) after adjustments for age, diabetes, hypertension and other confounders. The number of T cells significantly decreased in the severe group (0.5 vs. 0.9, P < 0.001). COVID-19 might mainly act on lymphocytes, particularly T lymphocytes. NLR was identified as an early risk factor for severe COVID-19 illness. Patients with increased NLR should be admitted to an isolation ward with respiratory monitoring and supportive care.

The data accumulated from 1972 to 1987 on the distribution and prevalence of tuberculosis in the badger population in Great Britain is reviewed. The current information on the influence of Mycobacterium bovis infection on badger population dynamics and its clinical effect on badgers is also summarized.