DNA sequencing of the vanC-2 gene was partially carried out on 10 isolates of Enterococcus casseliflavus obtained from 8 samples of imported chickens in Japan between July 1999 and June 2001 to evaluate the variation in the gene. Forty nucleotide substitutions in 36 codons were identified within 345 base pairs when compared with the vanC-2 sequence of the reference strain E. casseliflavus ATCC25788. Identical nucleotide substitutions were commonly found in the isolates recovered from chickens imported from both Brazil and China. Pulsed-field gel electrophoresis (PFGE) patterns of NotI-digested chromosomal DNA of these strains were distinguished by two, or more than six, band differences. These observations suggest that sequencing of the vanC-2 gene may be helpful for epidemiological investigation in combination with the PFGE analyses of the isolates, although particular genotypes are unlikely to be restricted to each of the countries that exported chickens.

Campylobacteriosis, the most frequent bacterial enteric disease, shows a clear yet unexplained seasonality. The study purpose was to explore the influence of seasonal fluctuation in the contamination of and in the behaviour exposures to two important sources of Campylobacter on the seasonality of campylobacteriosis. Time series analyses were applied to data collected through an integrated surveillance system in Canada in 2005–2010. Data included sporadic, domestically-acquired cases of Campylobacter jejuni infection, contamination of retail chicken meat and of surface water by C. jejuni, and exposure to each source through barbequing and swimming in natural waters. Seasonal patterns were evident for all variables with a peak in summer for human cases and for both exposures, in fall for chicken meat contamination, and in late fall for water contamination. Time series analyses showed that the observed campylobacteriosis summer peak could only be significantly linked to behaviour exposures rather than sources contamination (swimming rather than water contamination and barbequing rather than chicken meat contamination). The results indicate that the observed summer increase in human cases may be more the result of amplification through more frequent risky exposures rather than the result of an increase of the Campylobacter source contamination.

Recently, multiple-locus variable-number tandem-repeat analysis (MLVA) has been proposed as an alternative to pulsed-field gel electrophoresis (PFGE) for characterization of Escherichia coli O157:H7. In this study we characterized 118 E. coli O157:H7 isolates from cases of gastrointestinal disease in New Zealand using XbaI PFGE profiles and a MLVA scheme that assessed variability in eight polymorphic loci. The 118 isolates characterized included all 80 E. coli O157:H7 referred to New Zealand's Enteric Reference Laboratory in 2006 and 29 phage-type 2 isolates from 2005. When applied to these isolates the discriminatory power of PFGE and MLVA was not significantly different. However, MLVA data may be more epidemiologically relevant as isolates from family clusters of disease had identical MLVA profiles, even when the XbaI PFGE profiles differed slightly. Furthermore, most isolates with indistinguishable XbaI PFGE profiles that did not appear to be epidemiologically related had distinct MLVA profiles.

1. The present inquiry was designed to provide information on the relative frequency of infection in non-pulmonary tuberculosis with the human and bovine type of tubercle bacillus throughout the whole of England. A total of 149 pathologists at 120 collecting centres and 32 bacteriologists at 27 typing centres took part in the scheme. Two questionnaires relating to each patient were used, one to be filled in by the laboratory workers and one by the Tuberculosis Officer or other responsible official.

1. Tubercle bacilli were isolated and typed from 112 patients in Wales. of these strains, 19 or 17·0 % belonged to the bovine and 93 or 83 % to the human type (Table 16).

Comparison of bacterial counts of poultry carcass skin by the cotton swab and alginate swab methods showed no differences between the two sampling methods in total counts and Enterobacteriaceae counts. Also no differences were found in Salmonella isolations.

Carrion is a major source of botulinal toxin for animals. A type D strain of Clostridium botulinum differed from type A and B strains in producing (1) much higher concentrations of toxin in putrefying mouse carcasses at several different temperatures over a period of 35 days, (2) toxicity that sometimes persisted in mouse carcasses for at least a year, and (3) mouse carcasses with exceptionally high oral toxicity. Fish carcasses were much less favourable than mouse carcasses for type D toxigenesis.

The study, together with earlier studies on types C and E, indicated that carrion contaminated with C. botulinum type C or D is likely to be particularly dangerous for animals that may ingest it. This accords with the observation that carrion-transmitted botulism in animals is usually caused by type C or D.

In the rapidly developing city of Almaty, Kazakhstan, rates of hepatitis A have fallen, but no data on prevalence of antibody to hepatitis A virus (anti-HAV) exist with which to interpret incidence data. In the autumn of 2001, we determined the anti-HAV prevalence among household and school contacts of hepatitis A cases. For contacts aged 0–4 years, 5–9 years, 10–14 years, 15–19 years, or 20–30 years, immune prevalences were 9, 12, 33, 33 and 77% respectively, among immediate-family household contacts and 15, 28, 49, 52 and 77% respectively, among community contacts. Child community contacts were more likely to be immune than their immediate-family household counterparts (odds ratio 2·0, 95% confidence interval 1·3–3·2). Almaty is experiencing an epidemiological shift in hepatitis A incidence. Feasible and effective prevention strategies using hepatitis A vaccine should be explored.

A phylogenetic tree, which distinguishes between the serovars and serogroups of leptospires common in Central Europe was constructed using an established RAPD procedure together with digital reading and evaluation (using different computer software programs) of the generated amplified DNA patterns. The application of this procedure has revealed a consistent correspondence between serogroup and genotype (position in constructed tree) in 69 cases, and serovar and genotype in 72 cases, of wild strains of leptospires. There was an agreement between serovar and genotype in cases of strains of Grippotyphosa, Pomona, Mozdok, Arborea and Sorexjalna as well as between serogroup and genotype in cases of Australis, Bataviae and Sejroe. With the procedure used in this study, it was not possible to distinguish between reference strains of serovars Jalna, Bratislava and Lora (all serogroup Australis) as well as between serovars Icterohaemorrhagiae and Copenhageni (both of serogroup Icterohaemorrhagiae). In contrast to this, wild strains belonging to serogroup Sejroe were distributed between Polonica, Istrica, Saxkoebing and Sejroe serovars. Endemic strains of leptospires tested, were also distinguishable.

The prevalence of anti-retroviral therapy (ART) use over time and the incidence of AIDS in a cohort of HIV-seroconverting injecting drug users (IDUs) were assessed by means of a hospital-based study of IDUs with a well documented date of HIV infection. Use of ART and clinical endpoints were assessed by hospital records. Three calendar periods (before 1992, 1992–6 and 1997–2000) were defined as corresponding to modalities of ART available. Prevalence of ART usage in each calendar period, changes in medication and, hazard of AIDS in patients reaching the same duration of HIV infection at different calendar periods were analysed. In total, 132 IDUs with a median age of 23 years at seroconversion were followed up for 6.8 years (median) (range 0.2–15.7). At the end of the study, 58 patients (44%) had developed AIDS. Before the introduction of highly active anti-retroviral therapy (HAART) 12% of patients were on ART. Starting in 1997, an increasing proportion were receiving HAART with a prevalence of 39.5% by January 2000. Taking 1992–6 as the reference category the relative hazard of AIDS during 1997–2000 was 0.42 (95% CI, 0.1–1.1) (P = 0.09). A 40% penetration of HAART in a cohort of IDUs with known dates of seroconversion resulted in a 58% reduction of the hazard of AIDS.

Bank voles (Clethrionomys glareolus) serve as the reservoir for Puumala (PUU) virus, the aetiologic agent of nephropathia epidemica. The animals are believed to be persistently infected and the occurrence of serum antibodies is usually taken as an evidence of active infection. We found serum antibodies to PUU virus in 42 of 299 wild bank voles captured in a PUU virus endemic area. PUU virus RNA was demonstrated in lung specimens of 11 of these 42 animals and in 2 of them antigen was also found. Thus in the lungs of 31 of 42 seropositive animals neither PUU virus RNA nor antigen was detected. In 2 of 257 seronegative animals, lung specimens showed presence of PUU virus antigen and RNA. Isolation of PUU virus from lung tissue was successful in all 4 antigen-positive bank voles but in none of 16 tested antigen-negative animals. In conclusion, only a minority of bank voles with serum antibodies to PUU virus showed evidence of current infection.

Sera from healthy Greeks, Liberians and East Africans were tested for dye test and direct agglutinating toxoplasma antibodies. At a titre of 1/16 or more 137/228 Greeks, 84/133 Liberians, 2/13 Bondei infants, 3/7 Bondei adults, 3/9 Masai infants and 20/43 Baganda adults gave a dye test positive result. This confirms the wide-spread occurrence of this infection.

A study has been made of the properties of soluble antigen in the brains of infant mice infected intracerebrally with the Flury strain of rabies virus.

Soluble antigen is produced at the same time as infective virus, and reaches a high concentration in a period of 2–3 days.

It can be partially purified by precipitation at pH 4·3. It is partially resistant to the action of trypsin, RNAse and DNAse. It is relatively stable at pH 6–10.

Experimental results suggest that the soluble antigen remains antigenically active after heating at 56° C. and treatment with 0·5% phenol or 0·35% formal-dehyde, but that such heating markedly reduces the ability to stimulate formation of neutralizing antibody.

Rabbits and mice appear to differ in the production of neutralizing antibody following immunization against soluble antigen in which residual live virus was inactivated by heat, phenol or formaldehyde.

It is suggested that this difference may depend on the different susceptibility to traces of incompletely inactivated virus remaining in the immunizing antigens.

The authors are grateful to Miss T. Madsen for her assistance in some aspects of this work. Dr N. Sapeika kindly made available facilities for the in vitro anaphylaxis experiments.

Financial assistance was received from the Nkana-Kitwe and Chingola Poliomyelitis Research Funds.

This study aimed to identify an appropriate simple mathematical model to fit the number of coronavirus disease 2019 (COVID-19) cases at the national level for the early portion of the pandemic, before significant public health interventions could be enacted. The total number of cases for the COVID-19 epidemic over time in 28 countries was analysed and fit to several simple rate models. The resulting model parameters were used to extrapolate projections for more recent data. While the Gompertz growth model (mean R2 = 0.998) best fit the current data, uncertainties in the eventual case limit introduced significant model errors. However, the quadratic rate model (mean R2 = 0.992) fit the current data best for 25 (89%) countries as determined by R2 values of the remaining models. Projection to the future using the simple quadratic model accurately forecast the number of future total number of cases 50% of the time up to 10 days in advance. Extrapolation to the future with the simple exponential model significantly overpredicted the total number of future cases. These results demonstrate that accurate future predictions of the case load in a given country can be made using this very simple model.

A detailed analysis of equine (H3N8) influenza viruses isolated in Nigeria during early 1991 has been undertaken. Antigenic analysis and the complete nucleotide sequence of the HA gene of three Nigerian equine influenza viruses A/eq/Ibadan/4/91, A/eq/Ibadan/6/91 and A/eq/Ibadan/9/91 are presented and limited sequence analysis of each of the genes encoding the internal polypeptides of the virus has been carried out. These results establish that, despite the geographical location from which these viruses were isolated, two were similar to the viruses which were concurrently causing disease in Europe in 1989 and 1991 and were related to viruses that have been predominating in horses since 1985. The third was more closely related to viruses isolated from 1991 onward in Europe but also in other parts of the globe. A comparison of the nucleotide sequence of two of the viruses isolated in Nigeria (A/eq/Ibadan/4/91 and A/eq/Ibadan/6/91) with a European strain (A/eq/Suffolk/89) showed limited variation in the haemagglutinin gene which caused amino acid substitutions in one of the antigenic sites: this mutation resulted in the potential production of a new glycosylation site in antigenic site A. The other Nigerian virus (A/eq/Ibadan/9/91) showed only a single one amino acid change from another European strain (A/eq/Arundel/12369/91). The two distinct Nigerian viruses had several amino acid substitutions in the antigenic sites of the haemagglutinin glycoprotein.

A total of 21 rubella seronegative children vaccinated subcutaneously with Wistar RA 27/3 strain live attenuated rubella vaccine in a family study of vaccine virus transmissibility were reviewed after 6 years. Haemagglutinating inhibiting (HAI) antibody titres of sera collected 46 days, 2 years and 6 years after vaccination were compared. Antibody titres in the vaccinated subjects were not significantly influenced by time, infection in susceptible siblings or revaccination.

1. A new colicine type (type 15) of Shigella sonnei is described.

2. The epidemiological circumstances associated with its appearance in Edinburgh and Glasgow are summarized.

3. Our indices of reliability as an epidemiological marker are fulfilled by this new type.

Susceptible mice have been placed in contact with infective individuals of the same species, separated from them after a definite period, and placed in contact with a further group of normal mice. This process has then been repeated again and again, the number of groups exposed varying, in different experiments, from three to twelve. In this way the spread of infection has been limited to that occurring between any one group and the group immediately following it.

Under these circumstances infection has spread far less readily than was the cases in other experiments, in which the mice were retained as a single population, and in which infection could spread in any direction among all the individuals at risk.

A retrospective space–time permutation model with non-Euclidean distance criteria was applied within a high-complexity hospital setting to quantitatively explore cluster patterns of 273 patients infected with or colonized by carbapenemase-producing Klebsiella pneumoniae during 4 years. Results were compared to standard nosocomial active-surveillance methods. Two clusters were identified in the period, suggesting that space–time strategies for cluster quantification within confined environments may be useful.

Twenty progesterone-treated TO mice were infected intravaginally with Mycoplasma pulmonis. One month later, ten of the mice were given oestradiol which changed the reproductive cycle to the oestrous phase and within a week resulted in eradication of the organisms from six of them; vaginal persistence in the other mice may have been due, at least in part, to reinoculation of organisms from the oropharynx, a site heavily infected in all the mice. The majority of the mice not treated with oestradiol continued to shed the organisms from the vagina for at least 91 days. In another experiment, 19 oestradiol-treated BALB/c mice were infected intravaginally with M. hominis. One month later, nine of the mice were given progesterone which changed the reproductive cycle to the dioestrous phase and eradicated the organisms from seven within 2 weeks and from all of them within about a month. This was in contrast to the mice not given progesterone, the majority of which continued to shed the organisms for at least 167 days.

The post-war need for large numbers of dwellings has promoted renewed inquiry into the basic criteria by which good practice in the design and construction of buildings may be judged. More emphasis than ever before is now being put upon the functional characteristics of buildings regarded as living-spaces rather than as structures.