Commercial heat treatment procedures for molluscan shellfish are based on data obtained for the inactivation of hepatitis A virus (HAV) in cockles. However, the most frequently reported illness associated with consumption of bivalve molluscs is gastroenteritis caused by small round structured viruses (SRSVs) of the Norwalk group. Conditions for inactivation of SRSVs are unknown. In this study a feline calicivirus was used as a model for the SRSV group and conditions for its heat inactivation determined. Experiments showed that feline calicivirus is more readily inactivated in shellfish than HAV, and confirmed that current heating recommendations to the UK shellfish industry are adequate. A reverse transcription polymerase chain reaction (RT-PCR) assay for the detection of calicivirus in shellfish was developed and results compared with isolation in cell culture. The RT-PCR detected virus in some samples that failed to yield virus on culture. This has important implications if molecular virology techniques are to be used in the design and monitoring of shellfish treatment procedures and for routine testing of food samples.

Community-based immunization is the primary method available today by which to reduce the scale of morbidity, and, in certain countries, mortality, associated with the most common childhood viral and bacterial infections. The decline in the incidences of a number of important vaccine preventable infections, such as polio, diphtheria and measles, in many countries, and the worldwide eradication of the smallpox virus, is testimony to the effectiveness of this method of control.

1. A brief review of the literature on acid-fast bacilli found in skin lesions is given.

2. The characteristics are described of an acid-fast bacillus isolated from a skin lesion found in the South African Xenopus laevis.

3. Reasons are given to support the view that chromogenic acid-fast bacilli cultured from skin lesions belong to the group of ‘Saprophytic acid-fast bacilli’.

4. The possibility of using the Middlebrook-Dubos haemolysin test as a tool to differentiate atypical acid-fast bacilli is discussed.

Thanks are due to Dr Charles Pike for all the histological reports, to Mr T. R. West for the microphotographs, to Dr Piersma (Messrs Lederle) for the gift of special sensitive Old Tuberculin for the Middlebrook test, to Dr Nassau for patients' sera and the ‘Goss’ antigen and finally to Mr W. J. Fincham for the titrations of the haemolysin titres.

Antimicrobial susceptibilities of Vibrio cholerae strains isolated from cholera patients admitted to the Infectious Diseases Hospital, Calcutta, India for 6 years were analysed to determine the changing trends; 840 V. cholerae strains isolated in 1992–1997 were included in this study. Among V. cholerae serogoup O1 and O139, ampicillin resistance increased from 1992 (35 and 70%, respectively) to 1997 (both serogroups 100%). Resistance to furazolidone and streptomycin was constantly high among V. cholerae O1 strains with gradual increase in resistance to other drugs such as ciprofloxacin, co-trimoxazole, neomycin and nalidixic acid. V. cholerae O139 strains exhibited susceptibilities to furazolidone and streptomycin comparable with those of O1 strains. However, after initial increase in resistance to chloramphenicol and co-trimoxazole, all the V. cholerae O139 strains became susceptible to these two drugs from 1995 onwards. Both V. cholerae O1 and O139 remained largely susceptible to gentamicin and tetracycline. V. cholerae non-O1, non-O139 strains, in contrast, exhibited high levels of resistance to virtually every class of antimicrobial agents tested in this study especially from 1995. Kruskal–Wallis one-way analysis showed that V. cholerae O1 Ogawa serogroup exhibited significant yearly increase in resistance to nine antibiotics followed by non-O1 non-O139 and O139 strains to six antibiotics and two antibiotics respectively. Interesting observation encountered in this study was the dissipation of some of the resistant patterns commonly found among V. cholerae non-O1 non-O139 or O1 serogroups to the O139 serogroup and vice versa during the succeeding years.

Attempts to explain the clear seasonality of rotavirus infections have been made by relating disease incidence to climate factors; however, few studies have disentangled the effects of weather from other factors that might cause seasonality. We investigated the relationships between hospital visits for rotavirus diarrhoea and temperature, humidity and river level, in Dhaka, Bangladesh, using time-series analysis adjusting for other confounding seasonal factors. There was strong evidence for an increase in rotavirus diarrhoea at high temperatures, by 40·2% for each 1°C increase above a threshold (29°C). Relative humidity had a linear inverse relationship with the number of cases of rotavirus diarrhoea. River level, above a threshold (4·8 m), was associated with an increase in cases of rotavirus diarrhoea, by 5·5% per 10-cm river-level rise. Our findings provide evidence that factors associated with high temperature, low humidity and high river-level increase the incidence of rotavirus diarrhoea in Dhaka.

Lumpy skin disease (LSD) is an economically important, acute or sub-acute, viral disease of cattle that occurs across Africa and in the Middle East. The aim of this study was to investigate if lumpy skin disease virus (LSDV) can be transmitted mechanically by African brown ear ticks (Rhipicephalus appendiculatus Neum.). Laboratory-bred R. appendiculatus males were fed on experimentally infected viraemic ‘donor’ cattle. Partially fed male ticks were then transferred to feed on an uninfected ‘recipient’ cow. The recipient animal became viraemic, showed mild clinical signs of LSD and seroconverted. Additionally, R. appendiculatus males were found to transmit LSDV through feeding on skin lacking visible lesions, demonstrating that viraemic animals without lesions at the feeding site of ticks may be a source of infection. This is the first time that transmission of poxviruses by a tick species has been demonstrated and the importance of this mode of transmission in the spread of LSDV in endemic settings is discussed.

Inoculated orally, 16 Salmonella typhimurium strains belonging to 12 phage types varied greatly in their abilityto kill 1-day-old chickens; variation was noted even between strains of the same phage type. Fourteen strains belonging to 11 food poisoning serotypes other than S. typhimurium were practically non-lethal whenexamined in this manner. All of them were lethal by the intramuscular route but some were more so than others. Twowere more lethal by this route than one of the S. typhimurium strains that was highly lethal when given orally.With age, chickens rapidly became resistant to fatal infection with the food poisoning strains; given orally, a S.typhimurium strain killed 79 % of 1-day-old chickens but only 3 % of 2-day-old chickens. Of 2 specific poultrypathogenic strains, one, of S. gallinarum, was lethal by oral inoculation to chickens of all ages but the other, of S. pullorum, was only lethal to very young ones.

Some salmonella strains, such as those of S. infantis and S. menston, were more efficient at infecting and colonizing the alimentary tract of chickens than were the more virulent S. typhimurium strains, the S. gallinarum and S. pullorum strains and a S. cholerae-suis strain.

Impression plates from initially clean horizontal surfaces and floor areas in surgical wards showed a rapid accumulation of bacteria, mainly micrococci, which reached a fluctuating equilibrium after about 24 h. A later increase in bacterial contamination (mainly with aerobic sporing bacilli) to a higher equilibrium level after about 14 days occurred on uncleaned areas. Walls, even if left unwashed, acquired very few bacteria, but many were deposited locally when the wall was touched by a subject whose skin carried large numbers of staphylococci; moist exposed plaster was also heavily contaminated.

Regular use of a disinfectant (‘Sudol’ 1 in 100) in cleaning a ward floor did not reduce the equilibrium level of bacteria on the floor.

The transfer of staphylococci from contaminated to clean areas on the soles of shoes was demonstrated; the use of tacky and disinfectant mats did not appreciably reduce the transfer of bacteria by this route.

Staphylococci deposited on a wall by a disperser were shown to be transferred from the contaminated area of wall to the hands of another subject who did not previously carry the organism; this subject was shown to transfer the staphylo-coccus to a wall which he touched.

Attempts to redisperse by air movement Staph. aureus which had been shed by a disperser or by a contaminated blanket on to the floor surfaces had little effect; neither blowing with a hair dryer nor brisk exercise appeared to lift any of the staphylococci from a vinyl surface, and only small numbers were lifted by these measures from a terrazzo surface.

The hazards of infection from the inanimate environment are discussed.

Diabetes mellitus (DM) is a known risk factor for pulmonary tuberculosis (PTB). This study aimed to determine if type 2 DM alters manifestations and treatment outcome of PTB. Records of 217 consecutive culture-proven PTB patients were analysed retrospectively. The manifestations and treatment outcomes of 74 patients with type 2 DM (PTB-DM group) were compared to 143 patients without DM (PTB group). PTB-DM patients showed higher frequencies of fever, haemoptysis, positive acid-fast bacilli sputum smears, and consolidation, cavity, and lower lung field lesions on chest radiographs, and higher mortality rate. Furthermore, type 2 DM, age ⩾65 years, and extensive radiographic disease were factors independently associated with an unfavorable outcome. This study confirmed that clinical manifestations and chest radiographs of PTB patients associated with type 2 DM significantly depart from the typical presentation. Type 2 DM seems to have a negative effect on treatment outcome of PTB.

Clinical information was collected on 722 cases of Listeria monocytogenes infections in humans occurring in Britain between 1967 and 1985. This series comprised 34% (248 cases) associated with pregnancy and 66% (474 cases) in non-pregnant adults and juveniles. The cases not associated with pregnancy comprised: 76% in patients with severe underlying illness (of which 34% had central nervous system infections, and 42 % bacteraemia without involvement of the central nervous system); 21% in previously healthy individuals (of whom 18% had meningitis); and 3% in patients without bacteraemia or involvement of the central nervous system. Cases occurred most often in male patients over 40 years of age. The overall mortality was 44%.

Overall, the pattern of infection has altered to a disease of higher incidence, affecting most often susceptible non-pregnant individuals and the unborn.

An annual increase in incidence of listeriosis occurred in the autumn in all categories of patients.

(1) On the macroscopical alterations in the tissues of guinea-pigs which had been fed exclusively on bread, groats, and unpeeled grain.

By experimenting with the “one-sided” diets which were used in the experiments, mentioned in the foregoing paper on polyneuritis in poultry, we found that guinea-pigs also contract a disease, and that this disease is accompanied by very characteristic changes.

1. Ninety-three cases of primary infective gastroenteritis are reviewed. In only one instance was a known pathogen isolated.

2. The clinical features, epidemiology and postmortem findings are discussed.

3. A serologically homogeneous strain of Bact. coli is described which was isolated in over 90% of cases.

4. A discussion follows on the significance of these findings.

Bovine tuberculosis (bTB) is an important disease of cattle caused by infection with Mycobacterium bovis, a pathogen that may be extremely difficult to eradicate in the presence of a true wildlife reservoir. Our objective was to identify and review relevant literature and provide a succinct summary of current knowledge of risk factors for transmission of infection of cattle. Search strings were developed to identify publications from electronic databases to February 2015. Abstracts of 4255 papers identified were reviewed by three reviewers to determine whether the entire article was likely to contain relevant information. Risk factors could be broadly grouped as follows: animal (including nutrition and genetics), herd (including bTB and testing history), environment, wildlife and social factors. Many risk factors are inter-related and study designs often do not enable differentiation between cause and consequence of infection. Despite differences in study design and location, some risk factors are consistently identified, e.g. herd size, bTB history, presence of infected wildlife, whereas the evidence for others is less consistent and coherent, e.g. nutrition, local cattle movements. We have identified knowledge gaps where further research may result in an improved understanding of bTB transmission dynamics. The application of targeted, multifactorial disease control regimens that address a range of risk factors simultaneously is likely to be a key to effective, evidence-informed control strategies.

We present a mathematical transmission model of tuberculosis in the USA. The model is calibrated to recent trends of declining incidence in the US-born and foreign-born populations and is used in assessing relative impacts of treatment of latently infected individuals on elimination time, where elimination is defined as annual incidence <1 case/million. Provided current control efforts are maintained, elimination in the US-born population can be achieved before the end of this century. However, elimination in the foreign-born population is unlikely in this timeframe even with higher rates of targeted testing and treatment of residents of and immigrants to the USA with latent tuberculosis infection. Cutting transmission of disease as an interim step would shorten the time to elimination in the US-born population but foreign-born rates would remain above the elimination target.

We utilized Medline to perform a systematic review of the literature to quantify the aetiology of cellulitis with intact skin. Of 808 patients with cellulitis, 127–129 (15·7–16·0%) patients had positive needle aspiration and/or punch biopsy cultures from intact skin. Of the patients with positive cultures, 65 (50·4–51·2%) had cultures positive for Staphylococcus aureus, 35 (27·1–27·6%) for group A streptococcus, and 35–37 (27·1–29·1%) for other pathogens. The most common aetiology of cellulitis with intact skin, when it can be determined, is S. aureus, outnumbering group A streptococcus by a ratio of nearly 2:1. Given the increasing incidence of community-associated methicillin-resistant S. aureus infections, our findings may have critical therapeutic implications.

A cluster of four cases of haemolytic uraemic syndrome in children occurred in Northern Bohemia, Czech Republic, between 15 June and 7 July, 1995. All the cases had significantly elevated titres of anti-O157 lipopolysaccharide (LPS) antibodies as detected by the indirect haemagglutination assay. All but one of them had drunk unpasteurized goat's milk from the same farm within the week before the disease. Evidence of E. coli O157 infection was subsequently found in 5 of 15 regular drinkers of the farm's raw goat's milk; four of them were asymptomatic, 1 had mild diarrhoea at the end of June. Verocytotoxin 2-producing E. coli O157[ratio ]H7 strains of phage type 2 and of identical pulsed-field gel electrophoresis patterns were isolated from 1 of 2 farm goats and from 1 of the asymptomatic goat's milk drinkers. The frequency of anti-O157 LPS antibodies found among regular drinkers of the farm's raw goat's milk (33%; 5 of 15) was significantly higher than that found in control population (0%; none of 45) (P=0·0005; Fisher's exact test). Our findings indicate that goats may be a reservoir of E. coli O157[ratio ]H7 and a source of the infection for humans; raw goat's milk may serve as a vehicle of the pathogen transmission.

This study was conducted to estimate the varicella morbidity and mortality rates per age group among the non-immune population in France. Morbidity and mortality data for the years 1990–9 were derived from nationwide databases and surveillance systems. An incidence/prevalence model was designed to quantify the non-immune population per age group. The incidence of varicella in the non-immune population peaks during childhood and again in the 25–35 years age group. For children aged 1–4 years, adults aged 25–34 years and those older than 65 years, the hospitalization rates are respectively 235, 1438 and 8154 per 100 000 cases, and the death rates are respectively 7, 104 and 5345 per million cases. Case fatality or case hospitalization rates were not evenly distributed among adults and increased dramatically with age.

Particles released into the air by wringing the hands together were collected in a slit sampler before and after washing with bar soap, with three surgical scrubs, and after rubbing them with a spirit-based lotion. The particles were identified, their number estimated, those that bore bacteria counted, and the bacteria themselves classified. It was found that there was a significant increase, averaging 17-fold, in the number of particles carrying viable bacteria released after washing with soap. The increase in bacterial dissemination was suppressed if a surgical scrub was used in place of soap, or when the lotion was used without washing. The number of skin squames released increased by 18-fold or more after washing with soap or a surgical scrub, but not after using the lotion. This suggests that a surgical scrub should be used more widely in clinical practice, and that a spirit-based hand lotion might with advantage become a partial substitute for handwashing, particularly in areas where handwashing is frequent and iatrogenic coagulasenegative staphylococcal infection common.

Seven countries in Western Europe collected large, representative serum banks across the entire age range and tested them for diphtheria anti-toxin (sample size ranged from 2991 to 7715). Although a variety of assays were used, the results were all standardized to those of a reference laboratory and expressed in international units. The standardization process, and the availability of similar, large data sets allowed comparative analyses to be performed in which a high degree of confidence could be ascribed to observed epidemiological differences. The results showed that there were large differences in the proportion of adults with insufficient levels of protection amongst different countries. For instance, roughly 35% of 50- to 60-year-olds were found to be seronegative (titre [les ] 0·01 IU/ml) in Finland compared with 70–75% in the United Kingdom. Furthermore, the proportion of seronegative adults would be expected to increase in some countries, notably Italy and the western part of Germany. In those countries with vaccination of military recruits there was a marked sex-related difference in the proportion of seropositive individuals. All countries have high levels of infant vaccine coverage (> 90%) but the accelerated schedule in the United Kingdom appears to result in lower anti-toxin titres than elsewhere. In Sweden, booster doses are not offered until 10 years of age which results in large numbers of children with inadequate levels of protection. Although the United Kingdom and Sweden both have higher proportions of seronegative children than elsewhere the likelihood of a resurgence of diphtheria in these countries seems remote.

The paper examines predictions of the impact of various one-, two- and three-stage vaccination policies on the incidence of congenital rubella syndrome (CRS) in the United Kingdom with the aid of a mathematical model of the transmission dynamics of rubella virus. Parameter estimates for the model are derived from either serological data or case notifications, and special attention is given to the significance of age-related changes in the rate of exposure to rubella infection and heterogeneous mixing between age groups. Where possible, model predictions are compared with observed epidemiological trends.

The principal conclusion of the analyses is that benefit is to be gained in the UK, both in the short and long term, by the introduction of a multiple-stage vaccination policy involving high levels of vaccination coverage of young male and female children (at around two years of age) and teenage girls (between the ages of 10–15 years), plus continued surveillance and vaccination of adult women in the child-bearing age classes. Model predictions suggest that to reduce the incidence of CRS in future years, below the level generated by a continuation of the current UK policy (the vaccination of teenage girls), would require high rates of vaccination > 60%) of both boys and girls at around two years of age. Numerical studies also suggest that uniform vaccination coverage levels of greater than 80–85% of young male and female children could, in the long term (40 years or more), eradicate rubella virus from the population. The robustness of these conclusions with respect to the accuracy of parameter estimates and various assumptions concerning the pattern of age-related change in exposure to infections and ‘who acquires infection from whom’ is discussed.