As part of an interventional study to determine glycopeptide-resistant enterococci (GRE) acquisition on a three-ward haematology unit, rectal swabs were taken weekly from 293 patients recruited to the study between June 1995 and December 1996. The GRE isolates obtained from the first positive rectal swab from 120 colonized patients, the isolates from 7 patients with clinical infection and 43 isolates obtained from the ward environment were compared by pulsed-field gel electrophoresis (PFGE). Sixty-three of 120 patients were colonized by one of strains A-H, while 49 were colonized by unique strains. The first 18 weeks were associated with the highest prevalence of GRE by rectal swab, with a single strain A responsible for 52% of acquisitions on ward 2, 22% on ward 3 and 36% on ward 4. Other smaller ward associated clusters were evident. Environmental sampling of ward 2 during this time showed that all but 2 of 30 isolates were indistinguishable from strain A. As the GRE prevalence fell, rectal swab and environmental isolates became more heterogeneous, and strain A disappeared after week 55. GRE prevalence rose again in the final 15 weeks of the study, and a new predominant strain B emerged on ward 2 responsible for 50% of new acquisitions. In the seven patients with clinical infection with GRE, the clinical isolates were compared with the contemporaneous rectal swab isolate, and were found to be the same in only two cases. An analysis of five long-term carriers colonized for a median of 19 weeks (range 11–34) showed colonization with at least two and in one case six distinct strains, raising the question of how many strains may be colonizing a patient at any one time, and suggesting that multiple colonies should be analysed. These data suggest that cross-infection was an important factor in the spread of GRE when the colonization rate was high.

Tr. Lewisi has been cultivated by me for nine generations, the duration of cultivation extending over a period of nine months. The culture is still alive and is now in its tenth generation. A culture of Tr. Brucei was cultivated through three generations for a period slightly exceeding eighty days. These cultural experiments, however, in no way compare, in duration of time, with those of Novy and McNeal, who have cultivated Tr. Lewisi through twenty-six generations in two years, and Tr. Brucei through twenty-seven generations in eight months. Nagana trypanosomes degenerate rapidly in cultures and then become non-virulent, but a culture of Tr. Lewisi retains its infectivity for rats for a long period. From the study of well stained preparations it has been found that the cultural forms of the rat trypanosome differ considerably from those of the adult parasite found in the blood. The chief points of difference are: (1) The trypanosome is exceedingly motile and is generally spindle-shaped. (2) The centrosome is placed anteriorly. (3) The flagellum is very long and active and has but a short intracellular course, in consequence of the position of the centrosome, from which it arises. (4) No undulating membrane is apparent. (5) The trypanosomes form colonies, which ultimately contain many thousands of individuals. The flagella of the latter are directed centrally. In rats, infected with cultures of Tr. Lewisi, the usual forms of parasite appear. The cultural forms of Tr. Brucei resemble the trypanosomes found in the blood, but are more active. The chief points of difference, viz. development of two or more vacuoles and numerous granules and sometimes the breaking up of the chromatin of the nucleus, are probably due to degeneration. The colonies, found in cultures of Tr. Brucei, consist of a comparatively small number of trypanosomes, which are arranged irregularly or with their flagella directed peripherally. The differences between cultures of Tr. Lewisi and Tr. Brucei are summarised on page 43.

Using a self-paired observational study, the association between therapeutic oxytetracycline use and the prevalence of virulence genes in commensal Escherichia coli (E. coli) from cattle was examined. Faeces were collected from 39 yearling bulls prior to and after treatment with oxytetracycline and from 44 untreated animals. Between samplings all animals received in-feed chlortetracycline for 16 days. Five E. coli were isolated from each sample and tested by a polymerase chain reaction (PCR) capable of detecting all verotoxin (vt) genes. Positive isolates were further tested with a multiplex PCR to detect vt1, vt2, eaeA and hlyA. For vt, 23 animals were positive at both samplings, 26 negative at both samplings, 22 negative animals became positive and 12 positive animals became negative. Sixty-eight per cent of the discordant pairs changed from vt-negative to vt-positive (95% CI 48–80) suggesting pressure toward becoming vt-positive perhaps due to the transfer of genes due to mixing of cattle in the months between samplings or an effect of chlortetracycline.

1. A method is described for estimating subcutaneous tissue oxygen and carbon dioxide tensions in man.

2. Measurements were carried out before and at the end of carbon dioxide and oxygen saponin foam baths. These baths decrease the carbon dioxide and increase the oxygen subcutaneous tissue gas tensions. No appreciable differences were found between carbon dioxide and oxygen baths.

3. We conclude that gases do not diffuse through the skin in sufficient quantities to affect the subcutaneous tissue gas tensions.

Peptides of rabbit globin produced by tryptic digestion, were found to be highly protective against inactivation of freeze-thawed T4 phage. In concentrations of about 10−3 M the peptides protected the phage against inactivation by both concentrated NaBr in the unfrozen aqueous phase and the eutectic phase change.

Fractionation of the poptides by G25 Sephadex showed that peptide concentration rather than peptide size was the more important factor in determining the degree of protection of the phage by electrolyte effects. In contrast, protection against eutectic injury was strongly dependent on peptide size.

Possible mechanisms of action of the protective peptides are discussed.

Epidemiological data for Toxoplasma gondii regarding malignancy have gained increasing attention; however, the information about T. gondii infection among children with malignant lymphoma (ML) in China is unclear. Therefore, 314 children with lymphoma and 314 healthy children, age- and gender-matched, were recruited to estimate the seroprevalence of T. gondii in the participants and identify the risk factors of infection. Blood samples from all participants were collected and examined for T. gondii IgG and IgM antibodies using ELISA. The results showed that the overall seroprevalence of T. gondii antibodies (including IgG and/or IgM) in ML patients and healthy controls was 19.8% and 9.9%, respectively. Contact with the cats, consumption of oysters and history of chemotherapy were estimated to be the risk factors for T. gondii infection in children with lymphoma by multivariable logistic regression analysis, whereas in healthy children, contact with cats and consumption of oysters were the risk factors. Moreover, among various histological types of lymphoma, individuals with NK/T-cell lymphoma, B-small lymphocytic lymphoma, marginal zone B-lymphoma and Hodgkin's lymphoma had a higher seroprevalence than healthy controls (P < 0.05). These findings indicated the high prevalence of T. gondii infection in children with lymphoma, and hence, efforts should be performed to evaluate the effect of the infection further in lymphoma patients.

It has been reported that foetal death follows a seasonal pattern. Influenza virus infection has been postulated as one possible contributor to this seasonal variation. This ecological study explored the temporal association between the influenza activity and the frequency of foetal death. Time series analysis was conducted using weekly influenza-like illness consultation proportions from the Danish sentinel surveillance system and weekly proportions of spontaneous abortions and stillbirths from hospital registers from 1994 to 2009. The association was examined in an autoregressive (AR) integrated (I) moving average (MA) model and subsequently analysed with cross-correlation functions. Our findings confirmed the well-known seasonality in influenza, but also seasonality in spontaneous abortion. No clear pattern of seasonality was found for stillbirths, although the analysis exposed dependency between observations. One final AR integrated MA model was identified for the influenza-like illness (ILI) series. We found no statistically significant relationship between weekly influenza-like illness consultation proportions and weekly spontaneous abortion proportions (five lags: P = 0.52; 11 lags: P = 0.91) or weekly stillbirths (five lags: P = 0.93; 11 lags: P = 0.40). Exposure to circulating influenza during pregnancy was not associated with rates of spontaneous abortions or stillbirths. Seasonal variations in spontaneous abortion were confirmed and this phenomenon needs further investigation.

Between April 1983 and December 1985, 576 strains of Neisseria gonorrhoeae were isolated in our laboratory from patients attending Sexually Transmitted Diseases (STD) clinics. Of these, 61 (10·6%) were penicillinase-producing. Studies on these strains by plasmid analysis, auxotyping and serogrouping showed that the predominant type strains harboured the Asian resistance plasmid, were prototrophic, and were of serogroup WII/WIII. About half of the strains, both of the African and Asian type, harboured the transfer plasmid. Strains of serogroup WII/WIII were less sensitive to tetracycline and cefoxitin than serogroup WI strains.

The aims were to (1) investigate the aetiology of probable meningococcal disease, where a clinical diagnosis is made in the absence of laboratory data, and (2) evaluate the impact of the Men C vaccination programme in England and Wales. Multiple linear regression analyses were carried out using data reported to Enhanced Surveillance of Meningococcal Disease (ESMD) and laboratory reports of isolates of organisms causing symptoms that mimic meningococcal disease. Confirmed meningococcal disease appeared to be a significant predictor of probable disease. Thus, an additional reduction in meningococcal disease attributable to the serogroup C vaccination campaign was evident in probable disease over and above that observed in confirmed cases alone. Enteroviruses were a significant contributor to cases of probable meningitis and influenza appeared to be a significant contributor to probable cases of septicaemia. This analysis confirms the success seen following the Men C vaccination campaign and gives an indication of the aetiologies of other causes of probable meningitis and septicaemia reported to ESMD.

A study was made of the development of skin resistance and delayed hyper-sensitivity to vaccinia virus after immunization with inactivated vaccinia virus in rabbits. These vaccines are shown to increase skin resistance, and it is also shown that the development of this resistance is dependent upon the virus content of the vaccine. Skin resistance is shown to be related to the titre of circulating antibody rather than to the degree of delayed hypersensitivity. Possible reasons for conflicting reports in the literature on this subject are discussed.

An unusual skin reaction was seen in some animals when challenged with live virus after immunization with inactivated vaccine. The nature of these reactions is discussed.

Digital image processing (DIP) of bacterial smears is a new method of analysing the composition of the gut microbial flora. This method provides the opportunity to compare and evaluate differences in the complex highly concentrated anaerobic fraction of gut microbial flora, based on micromorphological differences. There is ample evidence that this fraction can be characterized as related or unrelated to the host organism by its immunogenicity. In this study germfree ND2 mice were associated with either related (rodent) SPF microflora (SPF-MF) or unrelated human MF (HUM-MF). DIP analysis was performed on original SPF-MF and HUM-MF and on the faeces of ex-germfree mice 4 weeks after association. The micromorphological pattern of highly concentrated anaerobic bacteria in faeces of HUM-MF associated ex-germfree mice was significantly different from SPF-MF associated counterparts with regard to the scores for elongation (P < 0·01) and morphological variety (P < 0·05). Moreover, gross morphological variability was present between individual HUM-MF associated mice but not between individual SPF-MF associated animals. No differences were found between original SPF and HUM-MF. The data are discussed with regard to differences in the presence of (non-)immunogenic bacteria and the ability for related and unrelated flora to colonize the murine gut. This study provides evidence that murine host specificity of microbial flora may not only be reflected in the number of non-immunogenic bacteria but also in the micromorphological pattern of highly concentrated anaerobic bacteria in faeces measured by DIP analysis.

Over a certain range there is a linear relationship between the amount of complement required for 50 % lysis and the amounts of one of the variables in the primary reaction mixture of a complement-fixation test when the third variable is present in a quantity sufficient to allow maximum fixation.

If this linear relationship were maintained as the concentration of the selected variable is progressively reduced, there would also be a linear relationship between the logarithms of the amounts of complement fixed and the logarithms of the amounts of the selected variable; in this case, the line with logarithmic co-ordinates will necessarily have unit slope.

When the fixation of small amounts of complement by several virus systems is measured, an approximately linear relationship using logarithmic co-ordinates has been demonstrated, but in many cases the line does not have unit slope. In this range, therefore, there is not a linear relationship when arithmetic co-ordinates are used.

A new design for a complement-fixation test is proposed, using isohaemolytic curves.

Mice killed shortly after receiving c. 2000 spores of a type E strain of Clostridium botulinum per os were incubated at one of five chosen temperatures together with bottles of cooked meat medium seeded with a similar inoculum. After incubation the rotting carcasses were homogenized. Sterile membrane filtrates of the homogenates (10%, w/v) and pure cultures were then titrated for toxicity. Some of the main findings were confirmed with two further type E strains.

Toxicity produced at 37 °C was poor in both carcasses and cultures (200–20000 mouse intraperitoneal LD/g or ml). It was good in both systems at 30 and 23 °C, usually reaching 20000–200000 LD/g or ml, and in carcasses occasionally more; at 30 °C maximal toxicity was reached more quickly in carcasses than in cultures. Prolonged incubation (36–118 days) at 30 or 23 °C resulted in complete loss of toxicity in virtually all carcasses but not in cultures. At 16 °C the development of toxicity in carcasses was strikingly greater than in cultures. At 9 °C neither system produced more than slight toxicity after prolonged incubation. Trypsinization increased the toxicity of cultures but not usually of carcasses. Unfiltered carcass homogenate (10%, w/v) with maximal intraperitoneal toxicity was harmless for mice by mouth in doses of 0·25 ml. These findings differed in important respects from those made earlier with a type C strain.

In 1885, the Dutch vital statistician, Prof. Van Pesch1 drew attention to a peculiarity of the curve of death rates at ages which he first noticed in the Netherlands’ statistics of 1870–79 and subsequently again found in the three following decades.

During my bacteriological investigations on the enlarged prostate gland which I am carrying out in conjunction with Mr Cuthbert Wallace, I have isolated a bacillus which presents the following characteristics and which appears to be, so far as I can ascertain, an organism which has not previously been met with.

Salmonella johannesburg (1, 40: b: e, n, x), a previously rare salmonella serotype, has established itself rapidly as an important and highly prevalent cause of gastroenteritis among children. The clinical features of the infection are usually mild but chronic. It has been suggested that S. johannesburg was introduced into Hong Kong through imported foods but no common vehicle could be traced as the source of infection. A thorough investigation of one paediatric ward in a general hospital revealed that non-infected patients admitted to the ward usually acquired S. johannesburg infection within 3–7 days, with or without symptoms. Thus hospital cross-infection could be a significant factor in contributing to its rapid spread in the community. Furthermore, the rapidity with which S. johannesburg spread was facilitated by (a) its tendency to produce a chronic infection, (b) its multiple resistance to antibiotics, and (c) the higher infectivity of S. johannesburg over other salmonellas endemic in this locality. These factors combined with the overcrowded conditions in many of the hospitals in Hong Kong facilitated the occurrence of hospital infection, which in its turn contributed to the spread of the infection in the local community.

Since it would hardly be possible to conceive a more complex medium for the conveyance of disease than cows' milk, the solution of the problems connected with the origin and source of epidemic diarrhoea is not materially advanced by the general recognition of the fact that in the majority of fatal cases, cows' milk is the vehicle of infection.

1. The existing scales of family consumption coefficients are reviewed and an attempt made to determine the sources from which they were developed. In the absence of definite information it was assumed that the majority of previous family coefficients were based upon the physiological requirements of the various age groups.

2. A family food budget survey recorded food purchased by the household. There was no guarantee that this food was eaten by the members of the house-hold in proportions similar to a scale of coefficients based upon physiological requirements.

3. Using the statistical material collected by the Commonwealth Advisory Council on Nutrition a scale of family coefficients based on calories “purchased” has been evolved by a form of statistical treatment which measured the additional food purchased for an additional person. This scale was:

This scale agrees more closely with that advanced by Lusk than any other.

4. Comparisons were drawn between the values obtained in this analysis and the physiological requirements of various age groups. It was found that for men and women and the older children the calories as purchased closely approximated to the physiological requirements, whilst for children of 2–3 years and under 2 years the former were considerably higher.

5. The protein purchased was within the range calculated to satisfy the physiological requirements.

In Sierra Leone, the Ebola virus disease (EVD) outbreak occurred with substantial differences between districts with someone even not affected. To monitor the epidemic, a community event-based surveillance system was set up, collecting data into the Viral Haemorrhagic Fever (VHF) database. We analysed the VHF database of Tonkolili district to describe the epidemiology of the EVD outbreak during July 2014–June 2015 (data availability). Multivariable analysis was used to identify risk factors for EVD, fatal EVD and barriers to healthcare access, by comparing EVD-positive vs. EVD-negative cases. Key-performance indicators for EVD response were also measured. Overall, 454 EVD-positive cases were reported. At multivariable analysis, the odds of EVD was higher among those reporting contacts with an EVD-positive/suspected case (odds ratio (OR) 2.47; 95% confidence interval (CI) 2.44–2.50; P < 0.01) and those attending funeral (OR 1.02; 95% CI 1.01–1.04; P < 0.01). EVD cases from Kunike chiefdom had a lower odds of death (OR 0.22; 95% CI 0.08–0.44; P < 0.01) and were also more likely to be hospitalised (OR 2.34; 95% CI 1.23–4.57; P < 0.05). Only 25.1% of alerts were generated within 1 day from symptom onset. EVD preparedness and response plans for Tonkolili should include social-mobilisation activities targeting Ebola/knowledge-attitudes-practice during funeral attendance, to avoid contact with suspected cases and to increase awareness on EVD symptoms, in order to reduce delays between symptom onset to alert generation and consequently improve the outbreak-response promptness.