For the purpose of assessing the effects of exposure to a special environment on a herd of mice, one naturally desires a control series, viz. a herd not exposed to a specific risk but otherwise in pari materia with our colonies under experiment.

Four thousand, five hundred and sixteen rodents of 27 species were captured in widely separated localities in South Africa over a period of ten years. Samples of spleen, lung, heart, liver and rectal tissue with faeces were tested for the presence of zoonotic bacteria and 109 isolations of Pasteurella pneumotropica were made from 11 species. Latent infection with the organism was found to be widespread although there were temporal fluctuations in prevalence. Field and laboratory evidence suggest that P. pneumotropica may be associated with, but not the primary cause of, rodent epizootics in the wild.

Up to the year 1906 tubercle bacilli were considered to occur in the faeces only in pulmonary or abdominal tuberculosis, due to ingestion of the infected sputum or to ulceration of the intestinal tract.

During the years 1903 and 1904 while engaged upon an investigation of the micro-organisms present in saliva, I had frequent occasion to make a quantitative bacteriological examination of this material. The object then in view was to define the bacteria that are most numerous in the mouth, so as to see if they could be applied to detect particulate pollution of air by material derived from the upper respiratory passages in a way similar to that in which B. coli is used to detect and measure excremental pollution of water. While certain streptocoeci were found to provide the index in question, particularly S. salivarius (which is constantly present to the extent of 10 to 100 millions per cubic centimetre of normal saliva) it was observed that among other bacteria present in the cultures were certain gram-negative cocci which frequently exceeded 100,000 per c.c. of the saliva of normal individuals.

Questionnaire survey of the drift mines of the British Isles revealed that the presence or absence of rat infestations could be related to the size of the mine in terms of manpower, large mines being more commonly infested than small ones. In addition, various features of drift mines and their surroundings, i.e. the presence of urban areas, nearby rat concentration points, canteen and surface stables, horses, the absence of buildings and the type of surface sanitation are all related to infestation. Field survey has shown that the extent of dilapidation and piling of waste material assists infestation. It has also indicated that the greater infestation of pits with large numbers of workmen is due to some extent to the extra cover provided by the greater number of surface buildings, these being few or lacking altogether in small pits.

At a mine at which changes in the rat population were studied it was seen that unsuccessful poisoning could leave a breeding nucleus of rats, but that there could also be a speedy re-invasion even after successful poison treatments. Whilst the surface rat population in the buildings of this mine was controlled there were no underground infestations. It appears, therefore, that regular inspection and control of surface infestations should in most cases prevent underground infestation.

This work was carried out under a research grant from Safety in Mines Research Establishment, Ministry of Power, and I am indebted to the Ministry for permission to publish the results. I should like to express my gratitude to the several members of the staff of the Safety in Mines Research Establishment, Sheffield, for the help they gave, in particular Mr C. S. W. Grice. I should like also to thank Prof. L. E. S. Eastham in whose department the work was carried out, Dr E. T. B. Francis who supervised it, Miss B. B. Jones of the Ministry of Agriculture, Fisheries and Food, and the many employees of the National Coal Board who assisted at various times.

Until recently there has been a general impression among a large proportion of the local medical faculty in Jerusalem that enteric fever was very uncommon and that typhus fever was practically unknown. As we are now basing our diagnosis of malaria increasingly upon the discovery of malarial parasites in the blood, we find that while on the one hand many of the most severe malarial infections, especially those with subtertian parasites, have little or no pyrexia, on the other hand, many cases which we should have called “ remittent malaria” or “malignant malaria” or “typho-malaria” in years gone by, are proving to be of other origin. A case of remittent pyrexia which does not yield in three, or at the outside five, days to efficient dosing with quinine is not in our experience a pure malarial infection.

In South Africa one finds quite a number of ailments occurring in the domesticated animals, and while the onset, symptoms, and morbid anatomy of those affected show the ailments to be peculiar to Africa, the names given to the maladies are unknown in any other country.

(1) Worli village is badly infested with rats, practically all M. rattus.

(2) Persistent trapping for one year appeared to reduce the rat population to approximately one quarter of the original number.

(3) Three cases of plague which occurred in the village were investigated. It is probable that these three cases all contracted the infection outside the village.

(4) In two instances there is evidence which points to infection having been introduced in the clothing or persons of people, and of this spreading in one instance to a guinea-pig, and in the other instance to rats.

Cultures of Staphylococcus aureus showing unstable resistance to kanamycin, streptomycin, lincomycin and penicillin have been preserved by drying. Particular attention has been paid to organisms showing linked resistance to pairs of these antibiotics. Recoveries of viable cells from the desiccates was high and the proportion of resistant and sensitive cells was maintained both during storage and during heating. The preservation of the organisms on ceramic beads stored in air over silica gel promises to be an effective and convenient method for maintaining staphylococcal desiccates during studies of unstable antibiotic resistance.

(1) The question of the alleged spread of infection by direct contact with a suffering case has been discussed. Our observations in a plague hospital and with material obtained from this hospital lead us to conclude that such a mode of spread does not exist. Support is given to this view by a consideration of the influence of imported cases on the spread of the epidemic and by an investigation of the relative frequency of single and multiple cases in houses and buildings. We have, further, referred to our experience that a rat epizootic is alone sufficient to account for a widespread dissemination of infection throughout a locality. A review of the whole of the evidence on this point brings us to the conclusion that contact with plague cases plays no part in the spread of the epidemic.

(2) In discussing the question of the infectivity of houses, evidence has been brought forward which points to the rat flea being the transmitting agent of infection from rat to man. Further, reasons have been given for the view that plague does not persist in a locality apart from infection amongst the rats.

(3) From arguments brought forward in the discussion of the two previous questions we conclude that the epidemic is wholly dependent upon the epizootics.

(4) It has been shown that infection may be transported to a distance by means of rat fleas in clothing or merchandise and that such infection, when imported into a hitherto uninfected locality, may give rise to an epizootic in the rats.

(5) Our observations lead us to conclude that plague in domestic animals in Bombay either does not occur or occurs so seldom that it cannot be said to possess any significance from an epidemiological standpoint.

It will, perhaps, be interesting to students of epidemiology to compare with the delicate and complex reactions of an experimental animal population the grosser reactions of a human population. In Australia the materials have been singularly favourable for a demographical study.

During a prolonged outbreak of meningococcal disease caused by serogroup B serotype 15 sulphonamide-resistant strains in one British health district, there was considerable variation in attack rates by town. General practitioner (GP) antibiotic prescribing rates were compared in high and low incidence towns. The only significant difference found was that erythromycin prescribing was more frequent in the high incidence towns (rate ratio 4·0, 95% CI 3·2–4·8, in March 1987 and 3·0, 95% CI 2·4–3·7, in November 1987). This was probably due to increased GP consultation rates for upper respiratory tract infection (URTI), but higher erythromycin usage may have increased meningococcal acquisition rates or susceptibility to meningococcal disease. Antibiotic prescribing rate should be further investigated in defined areas of high and low incidence of meningococcal disease.

The resistance of spores of B. subtilis var. niger produced in liquid synthetic medium and exposed to ethylene oxide on a nylon surface, has been shown to be almost identical to that for spores produced on a traditional solidified complex medium with exposure to the sterilant on aluminium foil. The use of short lengths of nylon tube as carriers allowed easy production and handling, with self-protection of the spore-bearing surface. Addition of a dye provided visual evidence of inoculation without affecting resistance to ethylene oxide. Such a monitor is suitable for use as a standardized biological challenge in routine ethylene oxide sterilization cycles.

Sera of 132 selected patients belonging to stages II, III or IV of clinical trachoma have been tested by CF-test against the ether-soluble, group-specific Bedsonia antigen, as well as by CF-inhibition test against an indicator system of the same group-reactive specificity.

On the basis of the serological results obtained, the following conclusions have been advanced:

Trachoma patients do not develop group-specific CF-inhibiting antibodies in their sera.

The group-reactive (anti-Bedsonia) CF-titres found in sera of trachoma patients represent residual titres developed in response to past infections with agents other than trachoma. There is no satisfactory explanation for the fact that in trachoma patients neither CF, nor CF-inhibiting antibodies develop against the group-reactive Bedsonia antigen, which is known to be produced also by the virus of trachoma.

Statistical analyses revealed that, in the group of stage IV trachomas, the mean values of the anti-Bedsonia CF-titres were significantly higher than those found in the groups of stage II or III, as well as that the factors responsible for that difference must be other than the duration of the trachoma.

A hypothesis was advanced to explain the appearance of the highest group specific mean-titre revealed by the group of stage IV cases.

Salmonella strains isolated in Palestine from camels could not be differentiated from a human strain isolated in the same country. The Palestine strains differ from S. kentucky by lower fermenting activities, but are antigenically identical with it.

Antimicrobial-resistant (AMR) bacteria are a threat to public health as they can resist treatment and pass along genetic material that allows other bacteria to become drug-resistant. To assess foodborne AMR risk, the Codex Guidelines for Risk Analysis of Foodborne AMR provide a framework for risk profiles and risk assessments. Several elements of a risk profile may benefit from a scoping review (ScR). To contribute to a larger risk profile structured according to the Codex Guidelines, our objective was to conduct a ScR of the current state of knowledge on the distribution, frequency and concentrations of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in salmon and shrimp. Articles were identified via a comprehensive search of five bibliographic databases. Two reviewers screened titles and abstracts for relevance and characterised full-text articles with screening forms developed a priori. Sixteen relevant studies were identified. This review found that there is a lack of Canadian data regarding ESBL-producing Enterobacteriaceae in salmon and shrimp. However, ESBL- producing Escherichia coli, Klebsiella pneumoniae and other Enterobacteriaceae have been isolated in multiple regions with a history of exporting seafood to Canada. The literature described herein will support future decision-making on this issue as research/surveillance and subsequent assessments are currently lacking.

Eleven cases of Weil's disease in miners from the west of Scotland have been encountered in the years 1937 and 1938. Only five showed jaundice.

Ten cases of infection previous to this period have been determined by serological means. Eight were jaundiced.

Information pointing to the occurrence of about eighteen more cases has been obtained from the Lanark public health authorities and from patients' statements.

The occurence of leptospiral infection appears limited at the moment but is quite serious in certain areas.

All available evidence points to the infectious being due to one specific strain of Leptospira.

I should like to thank the Physicians and Surgeons of the Royal Infirmary for permission to obtain sera from miners in their wards, and in particular Prof. A. W. Harrington, Dr J. C. Middleton and Dr J. N. Cruickshank for clinical details of cases. In addition, I would express my indebtedness to Dr J. M. Lang, Medical Officer of Health, Lanark, for the opportunity to investigate suspected cases, past and present.

The role of anthropometric status on dengue is uncertain. We investigated the relations between anthropometric characteristics (height, body mass index and waist circumference (WC)) and two dengue outcomes, seropositivity and hospitalisation, in a cross-sectional study of 2038 children (aged 2–15 years) and 408 adults (aged 18–72 years) from Bucaramanga, Colombia. Anthropometric variables were standardised by age and sex in children. Seropositivity was determined through immunoglobulin G antibodies; past hospitalisation for dengue was self-reported. We modelled the prevalence of each outcome by levels of anthropometric exposures using generalised estimating equations with restricted cubic splines. In children, dengue seropositivity was 60.8%; 9.9% of seropositive children reported prior hospitalisation for dengue. WC was positively associated with seropositivity in girls (90th vs. 10th percentile adjusted prevalence ratio (APR) = 1.19; 95% confidence interval (CI) 1.03–1.36). Among adults, dengue seropositivity was 95.1%; 8.1% of seropositive adults reported past hospitalisation. Height was inversely associated with seropositivity (APR = 0.90; 95% CI 0.83–0.99) and with hospitalisation history (APR = 0.19; 95% CI 0.04–0.79). WC was inversely associated with seropositivity (APR = 0.89; 95% CI 0.81–0.98). We conclude that anthropometry correlates with a history of dengue, but could not determine causation. Prospective studies are warranted to enhance causal inference on these questions.

A case-control study was conducted in a brucellosis low-prevalence area of NW Spain to determine factors associated with high within-flock small-ruminant brucellosis prevalence in 1998. Forty-one cases and 69 controls were selected and information from both official sources and personal interviews was retrieved for every flock. The relationship between variables obtained and flock status was assessed by unconditional multivariable logistic regression analysis. The introduction of replacement animals into the flock, the presence of older farmers, an inadequate brucellosis vaccination programme and higher flock seroprevalence in the town in 1997 were positively associated with case flocks. Thus, specific actions directed at farms presenting these characteristics should be included within official eradication programmes. In addition, for the 1999 campaign the time from sampling to culling the seropositive animals correlated positively (r=0·53; P<0·01) with the flock seroprevalence the following year, suggesting the need for a faster removal of the infected animals to increase the efficacy of the eradication campaigns.

The co-ordinates of the dwellings where cases of variola minor (alastrim) occurred during a small epidemic were used in a worked example of contour mapping of disease spread. The contoured variable was the date of onset, relative to an arbitrary base date, of the case introducing the disease into each of twenty-two households. Three contour maps prepared with slightly different computer programmes or dates exhibited similar concentric loops whose centres were close to the first infected household. The average rate of spread of the disease was estimated by regression of the number of days to onset of the first case in the household on the average distance from an arbitrary origin to the relevant contour line. The calculated average rate of spread was 1.22 metres per day. An additional map was contoured using the cumulative number of cases as the contoured variable, relative to the onset of the example epidemic.