An epidemiology analysis of a series of 12 Aeromonas hydrophila infections, including six of septicaemia, which occurred on several wards of one hospital during the summer of 1982 is presented. The hypothesis that the hospital water could be the source of these infections was supported by the isolation of 1–10 motile aeromonads per ml in most of the water samples collected from various points on the hospital water system. Electrophoretic esterase typing was used as an epidemiological screening method to determine the relationship between bacterial strains isolated from the patients and those from water samples. The epidemiology of A. hydrophila infection in the hospital was found to be complex. Amongst the 15 strains of A. hydrophila isolated from patients were 8 zymotypes, while amongst the 126 strains from the water samples there were 37. In some cases, several zymotypes were isolated simultaneously from the same tap water. On one ward, the same zymotype was found in 2 patients and in 2 water samples. The prophylactic measures taken in 1982–5 to avoid oral contamination of immunocompromised patients with infected hospital water have significantly reduced the number of cases of septicaemia. This success has constituted additional retrospective evidence for the water-borne origin of these infections.

Samples were collected at two abattoirs from four sites on pig carcasses as they were being placed in a chiller. Bacteriological examination showed that no single sampling site could be used to assess the microbiological status of pig carcass surfaces. Sampling from multiple sites on a carcass may be required to assess the degree of contamination by different bacteria. It is suggested that the hygiene of slaughtering and dressing of pig carcasses at an abattoir cannot be assessed on a single visit and that a number of visits are necessary to establish a hygiene pattern.

The Salmonella Reference Centre in Johannesburg received 14059 strains of human origin between 1979 and 1984. A significant proportion (6·3%) proved to belong to subspecies II. The majority were cultured from faecal material, usually associated with symptoms related to the gastrointestinal tract. They comprised 884 isolates, represented by 203 serotypes, of which 45 were new serotypes.

The poor hygienic conditions found in many rural areas, together with possible contamination of food and water by wild animals, may contribute to the greater frequency of human S.II infections and the widespread occurrence of unusual serotypes in man in this geographic region.

The aim of this study was to establish the risk of acquiring common respiratory and gastrointestinal illness for paediatric nurses. Using self-administered questionnaires, student nurses at two children's hospitals and students at one school of medical technology reported biweekly the number of minor illnesses, symptoms, and indicators of severity of infection over a 3-year period (1975–8). Although a systematic bias was evident with some symptoms, others appeared to be quite reliable. The following four syndromes were defined to estimate the risk: upper respiratory syndrome (URS), lower respiratory syndrome (LRS), respiratory and gastrointestinal syndrome (RGS), and gastrointestinal syndrome (GS). Surveillance days were allocated to groups with high- or low-intensity contact with children. The incidence of all illnesses was 2·9 per person-year in the low-intensity contact group and 4·4 per person-year in the high-intensity contact group. The reported incidence of LRS and RGS in the high-intensity contact group was 1·55 times higher than in the low-intensity group (P < 0·001). LRS and RGS incidence was similar in nurses at both schools. During low contact periods it corresponded to that of the medical technologists.

The occupational risk of acquiring minor respiratory infections for paediatric student nurses was estimated by performing serological examinations with influenza A, B, C, parainfluenza, mumps, respiratory syncytial virus, adenovirus and Mycoplasma pneumoniae at 6-month intervals over a period of 4 years in paediatric student nurses at two schools of nursing and students at one school of medical technology, litre increases against all tested agents occurred 1·86 times more often in the student nurses than in the medical technology students, the most frequent agents in both groups being influenza A and B. No difference in the relative distribution of the agents could be verified in the two occupational groups. Data on the protective value of pre-infectious antibody levels for influenza A, B, and coronavirus OC43 and on the importance of the spread of single agents among classmates are presented.

The study examines the distribution of Trichuris trichiura infection in a village community in St Lucia, West Indies. The infection intensity of the same age-stratified population was assessed (by drug expelled worm burden and faecal egg count) at the initiation of the study, and after 17 months of reinfection following treatment. The frequency distribution of worm numbers per person was similar at both periods of sampling. There was a significant correlation between the initial infection intensity of an individual, and the intensity acquired by the same individual following the 17 month period of reinfection. This relationship was observed in a broad range of host age classes. The study provides firm evidence that individuals are predisposed to heavy (or light) T. trichiura infection.

Botulism in UK cattle has been confirmed by demonstrating type C botulinum toxin in sera from affected animals. Evidence is presented indicating the source of intoxication to be poultry carcasses containing type C Clostridium botulinum and its toxin. The organism was also found in poultry litter and in alimentary tract samples from slaughtered animals. The implications of these findings are discussed.

The bacteriological status of beef carcasses was monitored at a commercial abattoir before and after two stages of modernization to the beef slaughterline which included changing from cradle dressing to dressing on an overhead rail, and the introduction of hot water spray cleaning of carcasses. Although small significant (P < 0·05) differences in bacterial count occurred among carcass sites within modernization stages, significant visit within stage variation and stage × site interactions prevented any significant change in overall count being observed among stages and carcass sites. Principal components analysis revealed small changes in the distribution of bacterial numbers on the sites sampled.

Trimethoprim resistance was examined in faecal bacteria obtained from chickens, sheep, cattle and pigs. The incidence of trimethoprim resistance in porcine strains was 17% (157/922) and, whereas 15·8% (146/922) of these bacteria were highly resistant, only 4% (37/922) of the isolates possessed trimethoprim resistance plasmids. Highly resistant porcine strains were obtained from 44% of the pig farms (41/93) but transferable trimethoprim resistance was found in isolates from 11% (10/93) of the farms. There was an association between the carriage of trimethoprim resistance plasmids and certain farms. Most of the resistance plasmids were not identical with those found in human clinical bacteria but one porcine plasmid was the same as the most ubiquitous trimethoprim resistance plasmid in Edinburgh.

A total of 270 serum samples collected in Chiang Mai province were examined for antibodies against leptospira using the microscopic agglutination test (MAT). Four of 40 serum specimens from patients who visited the hospital with the common cold, were positive with a titre of 20. Twelve (10·4%) of the 115 samples in the Doi Saket district showed a positive reaction. Only 2 of 115 sera of school children in Chiang Mai city had antibodies.

Specific serovars detected were Leptospira hebdomadis (5), L. australis (3), L. icterohaemorrhagiae (2), L. bataviae (2), and one each of L. canicola, L. javanica and L. pyrogenes. One case of mixed infection with L. hebdomadis and L. javanica, and L. auhnnnalis and L. australis were observed.

The hospital records of 242 patients with diagnostic chlamydial complement fixation (CF) titres (seroconversion and/or titre ≥ 64) found among 60000 patients screened for suspected viral illnesses were reviewed to study the clinical conditions associated with positive CF serology for Chlamydiae. After excluding typical genital C. trachomatis infections, the majority of the remainder were considered to represent C. psittaci infections. Respiratory symptoms were the most common clinical manifestations of chlamydial infections detectable by CF, but the majority (58%) of the patients did not have pneumonia. Abdominal, neurological as well as urinary tract symptoms were common. Cutaneous, joint, cardiac, genital and ocular manifestations were also noted. Fever (≥ 38·5 °C) was present in 62% of the patients. The ESR was raised (≥ 20 mm/h) in the majority of the patients (83%), but the leucocyte count was usually (86%) within normal limits. Because the clinical spectrum of C. psittaci infections is apparently broad, serological tests for detecting antibodies to C. psittaci (e.g. CF) should be used widely in various clinical conditions and not for patients with pneumonia alone.

An outbreak of 24 cases of hepatitis A in Aberdeen was traced to a large hotel in the city by epidemiological investigation. Food-specific questioning of those affected, their fellow diners and hotel staff, coupled with serological studies, implicated raspberry mousse prepared from frozen raspberries as the source of the infection. The raspberries were probably contaminated at the time of picking.

National surveys of the virulence of field strains of myxoma virus were carried out in 1975 (128 virus strains) and in 1981 (123 strains), using the virulence testing method employed in a similar survey in 1962. Results showed that the virulence of field strains had increased between 1962 and 1975, and again between 1975 and 1981. The increases in virulence are thought to be a result of the development of resistance to myxomatosis in wild rabbit populations. The effects of the changes in virulence and resistance are discussed.

An analysis of the meteorological conditions showed that the first outbreaks of myxomatosis in S.E.England in 1953 could have resulted from wind carriage of insects infected with myxoma virus from northern France. South-easterly winds on the night 11–12 August would have carried the insects 120–160 km from the Départements of Nord, Pas de Calais and Somme across the English Channel to near Edenbridge, Kent. The flight would have taken 6·5–8·5 h at wind speeds of 15–22 km h−1. On the night 11–12 August, temperatures increased with height (inversion) up to 500 m; at ground level temperature was around 19 °C and at 500 m was 25 °C. Insects would have travelled up to the top of the inversion arriving on 12 August as the inversion declined. Two or possibly three generations of infection would have taken place before the disease was seen around the middle of September 1953. The most likely insect was the mosquito Anopheles atroparvus which breeds along the coastal marshes of England and northern France and which has been shown experimentally and in the field to transmit myxoma virus mechanically.

The mite fauna of dust from cloth-covered seats of four passenger trains and bedding from a British Rail linen store in Glasgow was investigated; 22 samples containing 4488 mg of dust from a total surface area of 5·5 m2 were taken. Sixteen samples were positive for mites and 33 specimens belonging to 10 species were found. The most common species were Dermatophagoides pteronyssinus (Trouessart), Glycyphagus domesticus (De Geer), G. destructor (Schrank) and Euroglyphus maynei (Cooreman). The species composition bore considerable resemblance to that of house dust (although the density of mites was far lower) and the mites have probably been transported from homes via clothing and pets. Only five intact specimens, which may have been alive at the time of sampling, were found. The dust from trains consisted mostly of particles of soot. Very few skin scales, the food source of house dust mites, were detected. The small numbers of intact mites found and the absence of an identifiable food source make it unlikely that permanent populations of mites survive in upholstered seats on trains.