In October 2019, public health surveillance systems in Scotland identified an increase in the number of reported infections of Shiga toxin-producing Escherichia coli (STEC) O26:H11 involving bloody diarrhoea. Ultimately, across the United Kingdom (UK) 32 cases of STEC O26:H11 stx1a were identified, with the median age of 27 years and 64% were male; six cases were hospitalised. Among food exposures there was an association with consuming pre-packed sandwiches purchased at outlets belonging to a national food chain franchise (food outlet A) [odds ratio (OR) = 183.89, P < 0.001]. The common ingredient identified as a component of the majority of the sandwiches sold at food outlet A was a mixed salad of Apollo and Iceberg lettuce and spinach leaves. Microbiological testing of food and environmental samples were negative for STEC O26:H11, although STEC O36:H19 was isolated from a mixed salad sample taken from premises owned by food outlet A. Contamination of fresh produce is often due to a transient event and detection of the aetiological agent in food that has a short-shelf life is challenging. Robust, statistically significant epidemiological analysis should be sufficient evidence to direct timely and targeted on-farm investigations. A shift in focus from testing the microbiological quality of the produce to investigating the processes and practices through the supply chain and sampling the farm environment is recommended.

An outbreak of rubella in April 1996 involved four male British soldiers deployed to Bosnia–Herzegovina. All were helicopter ground crew who were members of the same unit and who periodically travelled to and worked at forward air refuelling stations in Bosnia. There was a potential for spread of the infection to adjacent British units, to troops of other nations in the peacekeeping force, and also to the local civilian population. The British force included 620 female personnel, some of whom may have been non-immune to rubella. One pregnant British servicewoman was repatriated to UK for her own protection. There was a potential health risk, including the possibility of congenital rubella syndrome, in the non-immune wives and partners of deployed male personnel, as a result of contact during the mid-tour home leave of the husbands or partners. The outbreak was monitored through a medical surveillance system known as ARRC 97, and was contained by prompt and rigorous control measures. This outbreak shows the importance of effective surveillance and of good microbiology laboratory support during military operations. The role of immunization against rubella during future military deployments is discussed.

We investigated the distribution of comorbidities among adult tuberculosis (TB) patients in Chiapas, the poorest Mexican state, with a high presence of indigenous population, and a corridor for migrants from Latin America. Secondary analysis on 5508 new adult TB patients diagnosed between 2010 and 2014 revealed that the most prevalent comorbidities were diabetes mellitus (DM; 19.1%) and undernutrition (14.4%). The prevalence of DM in these TB patients was significantly higher among middle aged (41–64 years) compared with older adults (⩾65 years) (38.6% vs. 23.2%; P < 0.0001). The prevalence of undernutrition was lower among those with DM, and higher in communities with high indigenous presence. Immigrants only comprised 2% of all TB cases, but were more likely to have unfavourable TB treatment outcomes (treatment failure, death and default) when compared with those born in Chiapas (29.5% vs. 11.1%; P < 0.05). Unfavourable TB outcomes were also more prevalent among the TB patients with undernutrition, HIV or older age, but not DM (P < 0.05). Our study in Chiapas illustrates the challenges of other regions worldwide where social (e.g. indigenous origin, poverty, migration) and host factors (DM, undernutrition, HIV, older age) are associated with TB. Further understanding of these critical factors will guide local policy makers and health providers to improve TB management.

Laboratory aspects of a programme of sewer swabbing during and after the Aberdeen typhoid fever outbreak, 1964, have been described. Results were discussed and reasons suggested for the relative insensitivity of methods employed in the isolation of Salmonella typhi. It was tentatively concluded that generalized sewer swabbing in a large city was not likely to be very helpful in tracing undetected excreters of S. typhi during and immediately after a major typhoid fever outbreak. The cost of the laboratory side of this investigation, for staff salaries, equipment, media, etc., was somewhat over £7000.

The authors wish to express thanks to Dr I. A. G. MacQueen, M.O.H., Aberdeen, and his staff including Mr H. B. Parry, Chief Sanitary Inspector and staff, for willing and helpful co-operation throughout this programme. Grateful acknowledgement is also made to Dr B. Moore of the Public Health Laboratory, Exeter; to Dr E. S. Anderson of the Enteric Reference Laboratory, London, for ‘phage typing’ the numerous isolations and to Dr Joan Taylor of the Salmonella Reference Laboratory, London, for assistance in typing Salmonella spp. isolated. Especial thanks are due to our laboratory technicians and other staff for the willing support given during the investigation.

The capture–recapture method was used to estimate the sensitivity of case finding in two national STD surveillance systems: (1) STD registration at municipal health services (STD-MHS); (2) statutory notification by clinicians (NNS). To identify those cases common to both surveillance systems, cases from 1995 were compared using individual identifiers. Estimated sensitivities for syphilis were: STD-MHS 31% (95% CI: 27–35%), NNS 64% (56–71%); and for gonorrhoea: STD-MHS 15% (14–18%), NNS 22% (19–25%). The combined sensitivity of both systems was 76% for syphilis and 34% for gonorrhoea. Differences in the sensitivity of the systems were significant. The NNS was more sensitive than the STD-MHS, and the identification of cases was significantly more sensitive for syphilis than for gonorrhoea. A stratified analysis showed comparable results for the two sexes. Knowledge on the sensitivity of surveillance systems is useful for public health decisions and essential for international comparisons.

A comprehensive analysis of the epidemiology of salmonellosis in a major hospital in Hong Kong from 1982–93 is reported. The trend of salmonella isolations over the past 12 years and changes in the occurrence of individual serotypes are delineated. A total of 5328 isolates were analyzed. Groups B (Salmonella typhimurium and S. derby) and E (S. anatum) were the commonest serogroups isolated from the intestinal tract in all age groups. A significant increase in the isolation of group D salmonellae has been observed since 1989. This is accounted for by a substantial rise in S. enteritidis isolation as seen in Western countries, despite a concomitant decrease of S. typhi. The extraintestinal isolation index (EII) is proposed as an index of the virulence potential of individual serotypes and serogroups. Group D salmonella was found to be the most invasive serogroup. While group D was the predominant serogroup isolated from extraintestinal sites in patients older than 1 year, group B serotypes (especially S. typhimurium) were more frequently seen in infants younger than 12 months.

The purpose of this study was to DNA fingerprint the majority (64 %) of isolates received at the Pertussis Reference Laboratory during the 1993 whooping cough epidemic by pulsed field gel electrophoresis of Xba I - generated restriction digests. Two DNA restriction patterns, types 1 and 3, predominated (40% and 23%. respectively, of 180 isolates) but type 2, identified in a previous study was notably absent. Twenty-one new DNA types occurred (24% of isolates), some being atypical as bands 155–230 kb were no longer conserved, but there was no statistically significant difference in their incidence in the upswing (June-September) compared to the downswing (October-December) phase of the epidemic. There was a relatively high proportion of new types, compared to type 1. at the peak (September). About 50% of isolates received were from the North Western Region, where 44% of isolates were DNA type 1. Whereas only 1 out of 10 isolates from Scotland were of this type, suggesting some geographic variation. Statistically significant findings included a higher proportion of isolates from female patients (P < 0·01), most marked in the 12–24 months age group (P < 0·05); a higher proportion of infants under 12 months requiring hospital admission compared to older children (P < 0·05); and a greater number of isolates from unvaccinated children (P < 0·01). Analysis of serotype according to four age groups (under 3 months, 3–12 months, 12–24 months and above 2 years) showed statistically significant differences (P < 0·05) with a noticeably lower proportion (38%) of serotype 1,3 in 3–12 months age group and higher prevalence (74%) of serotype 1,3 in the 12–24 months age group. There was no correlation between DNA type and serotype.

We conducted a case-control study examining risk factors for ciprofloxacin resistance in Campylobacter infections that were reported in 2004 and 2005 in two health regions in southern Alberta. The study questionnaire included questions about recent travel and antibiotic use, food consumption frequency, use of household and personal hygiene products with antibacterial agents, contact with animals, and potential misuse of antibiotics. Of the 210 patients who participated, 31·0% had ciprofloxacin-resistant Campylobacter infections. Foreign travel was the strongest predictor of resistance. Surprisingly, possession of antibiotics for future use was identified as a risk factor for resistance. We also examined the potential for participation bias and resistance misclassification to affect the resulting multivariable models. Participation bias appears to have had a substantial effect on the model results, but the estimated misclassification effect due to the use of different ciprofloxacin susceptibility testing methods was only slight.

An epidemic of enteritis due to infection of milk with a Flexner type dysentery bacillus, causing over 1000 cases and 72 deaths, occurred in Aberdeen in 1919, and has previously been recorded in the Journal of Hygiene(1). Another mild-borne outbreak of enteritis, causing 110 cases and no deaths, occurred in 1923, and has similarly been recorded(2). The cause of this outbreak was not determined, but was assumed to be due to a living bacillus of unrecognised type. In July, 1925, there occurred a further extensive outbreak of enteritis, which has been proved to be due to infection of milk with Bacillus enteritidis Gaertner, and as the infection has been proved to be of bovine origin, the Gaertner bacillus having been isolated from the udder and flesh of the diseased cow, as well as from the infective milk, it appears advisable to record the out-break in considerable detail.

A study of respiratory diseases in the semi-isolated community of Port Chalmers, New Zealand, began in April 1973. The intensive surveillance of a selected group of 26 families involved the weekly reporting of illness, the collection of specimens for virus, Group A streptococci and Mycoplasma pneumoniae isolation and the collection of sera at 6-month intervals. A total of 956 illnesses were reported during 32 months. The median number of illnesses per year were: infants 4·4, children 2·5, female adults 2·4 and male adults 2·0. Of all these illnesses, 57% were upper respiratory, 31% were lower respiratory and 9% were enteric. The severity of these illnesses was not greater than would be expected in open communities. Surveillance by pathogen isolation only of the whole community through the patients in the general practice was carried out concurrently.

A total of 640 nasopharyngeal swab specimens were collected from which 161 viruses, 47 Group A streptococci and 2 M. pneumoniae were isolated. The overall isolation rate was 33%. The similarities between the epidemiological patterns of respiratory disease in the open community and the isolated community are discussed.

Although viral respiratory tract infections may predispose to meningococcal disease, strong evidence that they do so exists only for influenza. Data on laboratory reported cases of respiratory syncytial virus (RSV) infections and meningococcal disease in England and Wales from mid-1989 to mid-1994 were analysed. Although the rise in RSV cases preceded the rise in meningococcal disease cases each winter, the interval between the rise and fall of the two diseases was inconsistent, no association was found between time series after removal of the seasonal component, and there was no evidence that more cases of meningococcal disease occurred in winters with more RSV disease. RSV may have less effect on the two most likely mechanisms whereby influenza predisposes to meningococcal disease, namely lowered immunity and impaired pharyngeal defences.

To assess the prevalence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) colonization in HIV-1-infected men who have sex with men (MSM), a cross-sectional study was conducted on 104 persons attending a large STI/HIV unit in Rome, Italy in the period June 2007–June 2008. Swabs obtained from both anterior nares and S. aureus isolates were characterized by phenotypic and genotypic methods. A total of 24 individuals (23·1%) were colonized with S. aureus but none carried MRSA. No statistically significant association between colonization with S. aureus and behavioural, clinical, virological or immunological characteristics was identified. This study indicates a lack of circulation of CA-MRSA in HIV-1-infected MSM in Italy and underscores large epidemiological differences between the USA and a European country, so that only locally conducted epidemiological studies can provide insight into the local circulation of CA-MRSA in general and selected populations.

A new technique to study the prevalence of circulating antibodies directed against different morphological groups (‘morphotypes’) of bacteria in fresh faeces is presented. The technique combines quantitative indirect immunofluorescence with digital image analysis. Plasma antibody titres and patterns of IgA, IgG and IgM isotype against morphotypes of faecal bacteria were determined in ten healthy individuals.

The efficacy of measles and pertussis vaccines was investigated using several different procedures based upon data routinely available at Local Health Authority level in England and Wales. It is demonstrated that such estimates can be derived by methods which can be carried out simply and routinely by local health department staff. Several theoretical and practical difficulties in the procedures are discussed. It is recommended that Health Authorities consider monitoring by a routine procedure based on crude case-control analysis of recorded vaccination status of notified cases compared with that of the population in the Child Health computer file, or of matched controls drawn from Child Health Registers. A simple protocol for such studies is provided.

An outbreak of cryptosporidiosis which affected 44 people in January and February 1991 was identified through local surveillance at a South London Public Health Laboratory. Preliminary enquiries revealed that more than half the patients were adult and that there were no common factors other than geographical association. A case-control study showed a significant association between illness and consumption of tap water supplied by a particular water company, as well as a dose response effect. There were no apparent breaches or irregularities in the water distribution system and no indication of a problem through routine monitoring indices. This incident demonstrates the problems of establishing the source of cryptosporidiosis outbreaks in the absence of evidence of environmental abnormality, as well as possibly indicating that water conforming to current treatment standards may occasionally contain sufficient numbers of Cryptosporidium oocysts to cause sporadic cases or clusters.

In a survey of enterovirus and adenovirus excretion in normal children in 1961–62, 25,600 faecal specimens were examined, 25,589 of them in cell culture and 17,596 in newborn mice.

Polioviruses were isolated from 156 (0·86%) specimens before Sabin vaccination was introduced in February 1962 and from 389 (5·27%) specimens after this. Coxsackie A viruses were isolated from 894 (5·08%) specimens, Coxsackie B viruses from 196 (0·77%), echoviruses from 278 (1·09%) and adenoviruses from 128 (0·50%).

The isolation rates of these viruses varied with sex, age, geographical area, type of local authority area and season.

The isolation rate of polioviruses before the introduction of Sabin vaccination was the same as in a previous survey carried out in 1957–58, although the rate was lower in Salk vaccinated children than in unvaccinated children. After Sabin vaccination began the isolation rate increased and Type 3 virus replaced Type 1 virus as the most prevalent virus type.

A study of the ability of 49 strains of FMD virus to replicate in BHK-21 monolayer cells maintained under a standard agar overlay containing 5·2 mM guanidine hydrochloride and to withstand heat inactivation at 54°C for 1 h showed that strains belonging to serotypes C, O and Asia 1 were generally more resistant to guanidine and heat stable than the SAT 1, 2 and 3 serotypes. The type A viruses as a whole occupied an intermediate position between these two groups.

In vitro passage in BHK-21 cells influenced the guanidine sensitivity of 3(O, C and SAT 3) of the 7 FMD serotypes suggesting that this is not a stable genetic marker. Heat stability of the FMD viruses, however, did not change on passage, suggesting that this is a stable characteristic inherent in any homogeneous FMD virus population.

Fifty-seven Salmonella Typhimurium strains isolated from poultry, swine and animal feed in Poland during the years 1979–1998 and 2000–2002 were analysed with conventional and molecular techniques. Antimicrobial resistance as well as multiresistance was found, respectively, in 80·1% and 56·1% of the isolates and most frequently among isolates from 2000–2002. Of several phage types noted, DT104 was prevalent among poultry, swine and feed isolates. DT104, U302 and non-typable strains had a multiple resistant profile (ACSSuT) due to the presence of class I integrons. Pulse-field gel electrophoresis of XbaI and BlnI digest showed high genomic similarity between the strains and confirmed clonal spread of S. Typhimurium infections. Plasmid profiling allowed further differentiation of the strains. We have, therefore, confirmed the appearance of S. Typhimurium DT104 showing genome integrated integron-mediated antimicrobial resistance in Poland. These findings are significant for public and animal health risks and document the dissemination of DT104 epidemic strains into new geographical regions.

Measurements of the rate of ventilation were made on 312 occasions in thirty-one rooms in (a) a block of older flats, (b) a block of modern flats, (c) three villa residences, and (d) a modern university building.

The rate of air change was determined by liberating a quantity of coal gas into the room and measuring the rate of its subsequent disappearance by means of a katharometer.

The effects on natural ventilation of air gratings and flues were studied in unheated rooms in two blocks of flats. The effective orifices of the gratings were 10·5 sq. in. in the modern flats and 6 sq. in. in the older ones. With the air gratings or flues (if any) closed the rates of air change were 0·55 and 0·71 per hour respectively. With the air gratings open the air change was increased to 0·83 per hour in the modern flats and to 1·04 per hour in the older ones.

The flues in the modern flats in connexion with gas fires were 4 in. diameter pipes (cross-sectional area, 12·6 sq. in.); in the older flats the ordinary fire-places were connected to standard flues and the area of the register openings was 53 sq. in. When the flues were sealed, the air changes per hour in the modern and older flats were 0·84 and 0·72 respectively and when the flues were opened these rates of ventilation were increased to 1·17 and 2·06 air changes per hour. In nine rooms in three other houses the average ventilation rates with the flues closed and open were respectively 0·82 and 1·76 air changes per hour.

The ordinary chimney flue, even without a fire at its base, was an efficient ventilator, but the flue of smaller dimensions was far less effective.

With windows open almost any required amount of ventilation could be obtained, and the observations showed that even when windows are opened only slightly the ventilation is distinctly increased. Thus, in flueless rooms of the modern flats, with doors and windows closed, but with the air grating open, the ventilation amounted to 0·83 air changes per hour, but with one casement only open to a width of 3/8 in. it was increased to 1·79 air changes.

The effects of various factors on the rate of air change are discussed and illustrated. Of these, outside wind speed appears to have most influence. The evidence regarding the effect on ventilation of the difference in temperature between the room air and the outside air is very conflicting. In the present observations, when outside wind speed is taken into account, no definite effect of temperature difference on air change is seen. But the experiments were made in unheated rooms and the temperature difference rarely exceeded 10° F., and in the majority of cases was much less.

The various recommended standards of air supply are discussed. Although certain bye-laws require a fresh-air supply of 1000 cu. ft. per person per hour, it is probable that where there is no overcrowding, as in the normally occupied dwelling-room, a ventilation rate of not less than 600 cu. ft. per person per hour should be sufficient to prevent body odours from becoming apparent.

The results of this inquiry show that in closed, flueless rooms, the air supply is likely to be much below 600 cu. ft. per hour per occupant.

On account of the low ventilation rates observed in flueless rooms it is desirable that the question of the use of flueless gas heaters in such rooms be reconsidered.

To the Editor:

In a previous report [1], we described significant risks for hepatitis B (HBV) and hepatitis C (HCV) positivity associated with receipt of tattoos, particularly while incarcerated, among a street-recruited population of injection drug users (IDUs) in New Mexico, United States from 1995 to 1997. Another recent report in this Journal, based on a study conducted on prisoners in Australia, found tattooing in prison to be an independent risk for HCV [2]. Another report also described a strong association between tattoos and HCV, but found the strongest association to be with commercial tattooing venues [3]. That study found the risk associated with receipt of tattoos in prison elevated, but not statistically significant. That same report reviewed other articles and found a significant risk for HCV infection associated with tattoos in six out of eight studies that had data available. Further, a recent U.S. Centers for Disease Control and Prevention (CDC) document summarized the literature on risks for hepatitis infections in correctional settings and developed extensive control guidelines [4].