The prevalence of infections caused by Mycobacterium bovis was estimated in two populations of wild animals in the south west of England. A variety of mammalian species was trapped on farm land where incidents of infection with tuberculosis had occurred in cattle. Bacteriological analysis of lymph node samples and lesions showed that the only animals acting as a reservoir for M. bovis were badgers. Examination of arthropod ectoparasites of infected badgers proved negative for M. bovis and suggests that these are unlikely to act as vectors in transmission of the disease.

A relatively simple method for the detection of intra-specific variation of Mycobacterium bovis is described, based on the ability of strains to utilize or remove amino acids from solution. Using the method, 31 strains of M. bovis, isolated from badgers and cattle, have been divided into four major groups with some additional sub-groups and intermediate strains. Preliminary results suggest that the biotypes observed are relatively stable. The method was used in the investigation of an outbreak of bovine tuberculosis in cattle in Gloucestershire where badgers were implicated as a source of infection. The results suggested that transmission of infection had occurred on at least two or three separate occasions. It is suggested that the method could be used in studying the epidemiology of bovine tuberculosis in wild animals, cattle and man.

During 1977 and 1978, 172 samples from 14 batches of domestic meat waste were examined for the presence of salmonellae. Each batch was derived from the domestic refuse collected from approximately 120 houses. Thirty-five strains of ten salmonella serotypes were isolated from 32 samples from 8 batches. The probable origin of these serotypes and their significance when domestic waste is exposed to predation by birds and animals on refuse tips is discussed.

Serum samples from 14 patients whose burns had become infected with streptococci of groups A (11 patients), C (one patient) or G (two patients), and from 19 burned patients without bacteriological evidence of streptococcal infection were examined for anti-streptococcal antibodies. Tests were made for anti-streptolysin O (ASO), anti-hyaluronidase (AH), anti-deoxyribonuclease B (anti-DNAase B) and antibody against M-associated protein (MAP). Sera from the patients with streptococcal infections were also examined, when this was practicable, for ‘bactericidal’ (anti-M) antibody and for antibody against the opacity factor (OF) of the infecting serotype.

In patients infected with group A streptococci, the ASO response was generally poor, except in patients infected with strains of type T12/M12, and the AH response was rather similar, but most of the patients gave a rapid and vigorous anti-DNAase B response, except when the burn was small or colonization occurred very late. Antibody to the M and MAP antigens, and to OF (when the infecting strain formed this), was weak and transient, or absent, except in three of four patients infected with streptococci of type T12/M12.

Five different types of liquid soap were studied in hospital wards, each during two months' use. Altogether 1306 finger print samples were taken from the hands of the staff by sampling twice a week and the acceptability of the soaps was measured by a questionnaire. During the use of different soaps only slight differences were found in the numbers of total bacteria or in the occurrence of Staph. aureus and gram-negative bacilli on the hands. During the use of the emulsion-type product studied, several persons who had dermatological problems had lower mean bacterial counts of the fingers than during the use of the other soaps. This soap was also favourably accepted by the staff. After over one year's use of pine oil soap and alcohol, the staff of the hospital was satisfied with the method. However, several persons with skin problems admitted to not using soap or alcohol. The considerable differences found in the acceptability of soaps imply that for use in hospital the choice of a soap acceptable to the nursing staff is important in promoting proper hand hygiene.

The faecal microflora of breast-fed infants, weaned children and adults has been examined in rural Nigeria and urban U.K. Breast-fed infants had a similar anaerobic flora dominated by bifidobacteria but bacteroides were isolated in less than a quarter of either community. Weaned children in both communities had greater numbers of bacteroides and clostridia than breast-fed infants. Even higher numbers of bacteroides and clostridia were present in U.K. adults but not in Nigerian adults. Numbers of bacteroides and clostridia were greater in a group of Nigerian infants drinking cow's milk than those receiving breast milk alone and lower in a group of weaned children with diarrhoea compared with uninfected subjects.

Chlorhexidine-containing cream is often used as an antimicrobial barrier to ascending urinary tract infection in patients with indwelling urethral catheters. The cream is dispensed in small tubes for personal use but repeated use of a tube still entails a potential infection hazard. The extent of cream contamination was analysed by emulsifying it in 1 % peptone broth with 1 % Tween-80 added as a wetting agent, and culturing quantitatively for bacteria and fungi by membrane filtration. Twenty-three per cent of cream samples and 35 % of swabs taken from outside the tube beneath the screw cap demonstrated microbial contamination. Isolates included potential pathogens such as enterococci, staphylococci, Proteus mirabilis, Pseudomonas aeruginosa, opportunists like Moraxella spp. and diphtheroids, and contaminants such as Bacillus spp., micrococci, and a mould of the genus Cladosporium. Contamination of cream with a particular bacterial strain was found to precede urinary tract infection with the same microbe. We recommend that chlorhexidine cream for this use be dispensed in single dose units to ensure sterility.

In 1976, an epidemic caused by infections with an influenza virus antigenically similar to A/Victoria/75 (H3N2) occurred in Houston, Texas. During this outbreak, 37 families (155 members) enrolled in the Houston Family Study were under observation. The families lived throughout the metropolitan area (Houston, Texas), and were representative of low income groups. The overall frequency of infection in family members was 27·7%. The frequency of infection was the highest for infants under one year of age and for their older siblings, 14 (37·8%) of 37 and 17 (33·3%) of 51, respectively. Eighteen (48·6%) of the 37 families had at least one infected member. Twelve of the 18 ‘infected’ families had school aged children, whereas only three of the 19 ‘non-infected’ families had school aged children (P < 0·01). These infected families were also larger and had increased household density (persons/rooms). The levels of pre-existing HI antibodies to A/Victoria/75 and A/Port Chalmers/73 were inversely related to frequencies of infection and illness associated with A/Victoria/75 virus. Three children required hospitalization as direct consequence of their infection with this H3N2 influenza virus. Antibody response to infection was related to previous experience with antigenically-related influenza A (H3N2) viruses according to Francis', ‘doctrine of original antigenic sin.’

The ability of the pyrogenic silica Aerosil 380R to exclude non-specific serum inhibitors (NSI) of rubella virus haemagglutination was evaluated. The developed procedure was compared with the kaolin, heparin/MnCl2 and dextran sulphate/CaCl2 methods.

Aerosil and kaolin were found superior for the elimination of non-specific inhibitors and high density lipoproteins (HDL). The other methods left NSI and HDL in a majority of the sera, occasionally in high titres. Aerosil seemed to be somewhat more efficient than kaolin in NSI and HDL exclusion. The Aerosil method offers the opportunity to detect sera with rubella antibody titres < 10. Among eight such sera, six were shown to contain rubella antibodies, while two were false positives.

The response of Acomys cahirinus to three anticoagulant rodenticides was investigated in the laboratory. In contrast to the other commensal rodents Rattus rattus and R. norvegicus, this species appears to be naturally very resistant to warfarin, difenacoum and brodifacoum. It is considered unlikely that anticoagulant poisons would be effective in the field for the control of A. cahirinus.

Over a 24 month period on six paediatric wards of different designs 169 cases of possible hospital-acquired respiratory virus infection were investigated. A variety of viruses was isolated from 82 cases, the most common being respiratory syncytial virus, influenza, parainfluenza, adenoviruses and rhinoviruses. A further 73 children developed respiratory symptoms between 3 and 300 days after admission but viruses were not demonstrable by the techniques used. These children were thought to have hospital-acquired infection nonetheless. Thirteen children were shown not to have acquired infection as the cause of their intercurrent illness. Most acquired infections occurred where toddlers were in cots in open wards. Children with trauma, including non-accidental injury, congenital malformations, mental retardation, failure to thrive or neoplasia were most likely to become infected. Almost 20 % of children suffered from croup or lower respiratory tract illness as a result of their acquired infection. The figure was 41 % if those less than 12 months old were considered alone. Most episodes settled quickly but in a few children investigations or surgery were delayed for a few days.

Young Rhesus monkeys (Macaca mulatta) were infected orally with a human strain of Campylobacter jejuni. The disease induced was mild, with inappetence and diarrhoea of short duration, but prolonged intermittent excretion of the bacteria in the faeces occurred. Bacteraemia was generally present for 2–3 days and later the organisms localized in the liver and gall bladder. Recovered animals, when challenged with the same strain, showed no clinical symptoms, no bacteraemia, and excreted the organisms in the faeces for only 3 days.

Recent New Zealand and Australian isolates of Salmonella typhimurium phage type 179 were studied for relatedness by colony incompatibility. This established that all but one strain of the New Zealand groups probably formed a clone despite carrying a variety of plasmids. The Australian strains showed a far greater diversity. This study demonstrates the epidemiological usefulness of the colony incompatibility reactions.

Pseudomonas aeruginosa was isolated from the ears of 18 of the 25 members of a team of competitive swimmers who complained of painful discharging ears. This group of swimmers trained twice daily in the pool, in the early morning and late afternoon. In contrast swabbing of the ears of a similar group of 54 competitive swimmers who used the pool only in the afternoon revealed only one swimmer with P. aeruginosa. Investigation of the swimming pool revealed that chlorination was often inadequate when the first group of swimmers were training in the early morning. Strains of P. aeruginosa were isolated from various sites around the pool and from the bag of a vacuum used to clean the pool.

Pyocin typing, serotyping and phage typing were performed on all isolates. The dominant strain recovered from the swimmers' ears was found to be almost identical to that from the vacuum bag and belonged to serotype 0–11 which has been particularly associated with outbreaks of P. aeruginosa infection in whirlpools in the United States.

These results support the hypothesis that there is a direct correlation between the development of otitis externa and swimming in water contaminated with P. aeruginosa.

Baiting with 0·005% bromadiolone in medium oatmeal or soaked wheat completely controlled infestations of warfarin-resistant rats on farms when surplus amounts of the poisoned baits were maintained until rats ceased to feed on them. The speed with which control was achieved was the same as with other anticoagulants that have been tested in this way.

Poison baiting with 0·005% bromadiolone for only 1, 4 or 7 days achieved respectively about 49, 77 and 81% control of similar farm rat infestations.

Modified brilliant green agar (BGA), Muller-Kauffmann tetrathionate, Rappaport's and selenite F broths were compared for their efficiency in isolating salmonellas from pigs and their excreta. It was concluded that BGA and Rappaport's broth were the media of choice. Where searches were made for Salmonella choleraesuis alone, the use of a trehalose McConkey agar provided a rapid method of differentiating S. cholerae-suis, which does not ferment trehalose, from the majority of other salmonellas, which do ferment trehalose.

Casualties were collected from two farms where infection with S. cholerae-suis was endemic. The isolation rates of S. cholerae-suis from different carcase sites were compared in order to determine the relative importance of the salivary, upper respiratory and faecal routes of excretion. S. cholerae-suis was isolated from numerous carcase sites in carriers including the salivary glands, tonsils, trachea and lungs. However, isolations from the nasal passages, mouth, pharynx and gastro-intestinal tract of carriers were either infrequent or absent. When, in a further study, S. cholerae-suis was isolated from only 3/414 faeces, 1/170 nasal swabs and not at all from 170 oral swabs taken from live pigs, it was concluded that there must be more significant modes of transmission than from the salivary glands, upper respiratory or gastro-intestinal tracts. Cannibalism was considered to be a possibility.

In contrast to S. cholerae-suis, other salmonellas were frequently isolated from randomly collected faeces and from the gastro-intestinal tract as well as other sites in casualties.