Examination of sera from 184 children aged between 0 and 12 years and 161 adults revealed a close correlation between age and the level of humoral anti-RS virus immunity. Secretory IgG antibodies were found in children in their first months of life. Evidence for their release into secretions from the serum was obtained. This might explain the positive correlation between serum antibody levels in women recently confined with the morbidity due to RS virus in children during their first months of life. Secretory IgA antibodies were found from 4 months untill old age. The secretions of children and adults contained virus-neutralizing activity which was non-immunoglobulin in nature, as well as antibodies. However, in contrast to secretory antibody this material did not prevent development of severe RS virus infections.

In 1986 and 1987 foot-and-mouth disease virus (FMDV) serotype A was isolated from outbreaks of disease in Saudi Arabia and Iran. Selected virus isolates were antigenically distinct from the prototype A22 virus strain (A22/Iraq/64), but were serologically related to each other. However, polyacrylamide gel electrophoresis showed that whilst the respective Saudi Arabian structural polypeptides were homogeneous, those from an Iran isolate were distinct. Direct sequencing of part of the P-1D (VP1) gene demonstrated considerable difference in nucleotide homology between the two groups of viruses; the Saudi Arabian viruses were closely related to each other but only distantly related to both the A22 prototype virus strain and the Iranian virus isolate. The latter viruses were only slightly more closely related to each other. Thus there appeared to be at least two distinct FMDV type A variants co-circulating in the Middle East, both of which differed considerably from the classical A22 subtype.

The stool samples of 75 patients with gastroenteritis and/or loose and watery faeces at three hospitals and one clinic in Zaria were examined for Cryptosporidium. The stool samples were concentrated by the formol–ether method and stained with safranin–methylene blue. Sixteen (21%) samples were positive. The rate of detection was higher among females (27%) than males (17%) and among adults (29%) than children (8%). The study confirmed the presence and possible significance of Cryptosporidium, which is a known zoonotic protozoan, in the aetiology of human gastroenteritis in Zaria, Nigeria.

During much of the present century, the population of herring gulls in Britain has increased rapidly (Cramp, Bourne & Saunders, 1973; Chabrzyk & Coulson, 1976; Monaghan & Coulson, 1977). Accompanying this changes was an increased utilization by these birds of human waste as a food supply, particularly sewage and refuse emanating from our towns and cities (Monaghan, 1983; Horton et al. 1983). This, coupled with their habits of roosting on agricultural land and water storage reservoirs and of breeding on inhabited buildings, has given rise to concern over the role of these birds in the spread of disease to man and domestic animals (e.g. Fenlon, 1981; Reilly et al. 1981; Butterfield et al. 1983; Monaghan et al. 1985; Girdwood et al. 1986).

An antiglobulin enzyme-linked immunosorbent assay for rubella-specific IgG1 and IgG3 was adapted to measure antibody avidity by incorporating a mild protein denaturant, diethylamine (DEA), into the serum diluent. Sera were tested at varying dilutions, both with and without DEA, if they contained sufficient specific IgG1 or IgG3. The optical density (OD) was measured and curves were plotted. The highest OD (V) was noted and halved (V/2). The distance between the OD curves at V/2 was measured as the DEA shift value.

Sera were examined from people whose sera contained rubella-specific antibodies as a consequence of infection or vaccination in the distant past (24 sera), recent primary rubella (66 sera), symptomatic reinfection (11 sera) or asymptomatic reinfection (64 sera). For specific IgG1 the DEA shift value was <O·6 for cases of rubella in the distant past, compared with >0·8 for the first month after primary infection. The maximum DEA shift value for the sera from cases of reinfection was 0·65.

No serum from cases of rubella in the distant past contained sufficient specific IgG3 to estimate avidity. The sera collected within 1 month of onset of primary rubella gave DEA shift values >O·7 compared with sera from reinfections, which gave DEA shift values <O·6, except for two sera from a case of symptomatic reinfection.

Thus the assessment of specific IgG subclass avidity is of value in differentiating serologically primary rubella from reinfection.

Two hundred and seventy-five consecutive clinical isolates of coagulase-negative staphylococci, including strains associated with disease, contaminants and skin colonizers, were speciated, tested for slime production and for their sensitivity to a range of antibiotics. Staphylococcus epidermidis was the most commonly identified species, comprising 63% of all isolates. Slime production was detected in half the strains of Staph. epidermidis, Staph. haemolyticus and Staph. Saprophyticus but was rare in other species. Most Staph. haemolyticus strains and approximately half of the Staph. epidermidis strains were resistant to five or more antibiotics. A significant association was found between slime production and multiple antibiotic resistance. For catheter-associated strains, clinical relevance was predictable by species i.e. Staph. epidermidis. Multi-resistant slime-positive Staph. haemolyticus strains, although infrequently associated with disease, were common skin colonizers, presumably acquired from the hospital environment. We describe a practical and inexpensive scheme for thespeciation of human coagulase-negative staphylococcal isolates.

Gastric campylobacter-like organisms (CLO) were isolated from gastric tissues removed at sacrifice from 17 mature ferrets; all animals were colonized, but no macroscopic mucosal lesions or histological features of chronic gastritis were seen. The isolates resembled Campylobacter pylori in many cultural and biochemical characteristics, and produced substantial urease activity, but there were sufficient differences from C. pylori to suggest that ferret gastric CLO represents a separate species. Comparison of human C. pylori and ferret gastric CLO may help to clucidate the pathogenicity of the former in patients with gastritis, and the ferret may serve as a useful animal model for the study of C. pylori infection.

Removal of thermophilic campylobacters from sewage at three different stages of treatment at a trickling filter sewage works has been assessed. Samples of incoming sewage, primary sedimentation effluent and final effluent were taken daily from 06.00 h to 20.00 h for 5 consecutive days and the numbers of campylobacters determined by using a most probable number method. Each sample was cultured using 2 h pre–enrichment followed by enrichment in Preston broth for 48 h and detection by plating. Over 78% of the incoming campylobacters were removed after primary sedimentation and < 0.1% remained in the final effluent. Campylobacter jejun biotype I and biotype II constituted 81.5% and 15.9% respectively of the 232 isolates tested. Serotypes common in sewage were common in human faces. It appears that the trickling filter sewage works removes most of the campylobacters entering the sewage works, but large numbers, estimated to be approximately 1010, are released into the environment daily from a local sewage works.

Five rubella antigens were evaluated in an antiglobulin enzyme-linked immunosorbent assay for rubella-specific IgG subclass antibody. One monoclonal anti-human IgG subclass antibody was used for each of IgG1, IgG2 and IgG4, but two were compared for IgG3. A total of 101 sera were tested from cases of rubella in the distant past and from cases of primary rubella, reinfection and following immunization. Only one serum gave a discrepant result for specific IgG1, being positive with only one rubella antigen, a commercially prepared antigen coated on to microtitre wells (Enzygnost; Behringwerke). No sera contained detectable specific IgG2. Only four sera contained specific IgG4, and this was detectable only with Enzygnost antigen. For specific IgG3 little difference was observed between the two monoclonal anti-human IgG3 subclass antibodies; only two very weakly positive sera gave discrepant results. However, varying results were obtained for specific IgG3 with the different antigens. Enzygnost gave more positive results for specific IgG3 with most categories of sera.

It is concluded that the differences between various reports of the rubella-specific IgG subclass profile cannot be explained entirely by the use of different rubella antigens.

Between 1980–5, 224 outbreaks of salmonellosis associated with poultry-meat were reported in Scotland. In total 2245 persons were affected, 12 of whom died. Twenty-one salmonella serotypes were identified from those affected, while 33 serotypes were isolated from poultry during routine monitoring and disease investigation. Existing measures to prevent the spread of salmonellae within poultry flocks and processing plants are failing. It is suggested that irradiation of poultry-meat may be the only effective method of reducing the public health problem of poultry-borne salmonellosis.

Colonization of the intestine by putative pathogens was followed longitudinally in a cohort of 56 infants born during one calendar year in a rural Mexican village with faecal cultures taken every fortnight and every time a child had diarrhoea. The frequency of isolation of pathogens during episodes of diarrhoea was compared with that of matched controls from the same cohort. Incidence of diarrhoea during the first year of life was 98%, diminishing to 93% during the second year. The incidence curves for each year were not significantly different (P > 0·1). Isolation of enteropathogenic Escherichia coli, enterotoxigenic Escherichia coli producing heat-stable (ST) and/or heat-labile (LT) enterotoxins and rotaviruses was significantly higher in infants with diarrhoea during the first 2 years of life. In the case of shigella, although no significant differences were found by semester of life, 13 of 16 children in which these strains were found had diarrhoea. Isolation of Salmonella spp., Campylobacter spp. and protozoa were not significantly different in the two groups during the period studied. Strains showing localized adherence to HEp-2 cells or the presence of colonization factor antigens I or E8775 were found with significantly higher frequency in children with diarrhoea. Eighty-two percent of ST+ or LT+ ETEC strains isolated produced one of the three known colonization factors.

Campylobacter organisms isolated from water samples taken weekly from ponds and land-drains in the City of Hull were compared with isolates from humans. Of 314 campylobacter organisms isolated from patients, 237 (75.5%) of the strains were identified as typical Campylobacter jejuni, whilst of 125 identified strains isolated from the water samples, 85 (68%) resembled C. jejuni in most respects but were hippurate hydrolysis negative by the Hwang and Ederer method. The ponds and land drains in the city were therefore not a source of campylobacteriosis in the people living near these water courses. The atypical C. jejuni strains isolated from the environment may be mistaken for the C. jejuni strains which cause human infection. It is therefore essential that such strains are fully identified before attributing human and animal infections to their ingestion.

A seroepidemiological survey was conducted on subjects who had received a full vaccination course with live attenuated poliovirus 2–16 years before. For strains 1 and 2 prevalence of seropositives and median values dropped gradually during the first 10 years; strain 3 showed a much earlier decline. Environmental displacement of wild poliovirus by the attenuated, less immunogenic strain might eventually induce a ‘gap’, should complacency hamper needed vaccination efforts.

Three human volunteer experiments were performed in which river water expected to contain campylobacter organisms was ingested. Despite the ingestion of over 44000 organisms in one experiment, the subject did not suffer any symptoms, nor were campylobacter organisms excreted, nor was an antibody response to the ingested strains detected. The campylobacter organisms ingested resembled Campylobacter jejuni on colonial and microscopic morphology but were hippurate negative, and were distinct from C. coli. These environmental campylobacter strains appear to be non-pathogenic, however they may be mistaken for C. Jejuni or C.coli if they are not fully identified.

Recent reports of the isolation of microorganisms from used soap bars have raised the concern that bacteria may be transferred from contaminated soap bars during handwashing. Since only one study addressing this question has been published, we developed an additional procedure to test this concern. In our new method prewashed and softened commercial deodorant soap bars (0·8% triclocarban) not active against Gram-negative bacteria were inoculated with Escherichia coli and Pseudomonas aeruginosa to give mean total survival levels of 4·4 × 105 c.f.u. per bar which was 70-fold higher than those reported on used soap bars. Sixteen panelists were instructed to wash with the inoculated bars using their normal handwashing procedure. After washing, none of the 16 panelists had detectable levels of either test bacterium on their hands. Thus, the results obtained using our new method were in complete agreement with those obtained with the previously published method even though the two methods differ in a number of procedural aspects. These findings, along with other published reports, show that little hazard exists in routine handwashing with previously used soap bars and support the frequent use of soap and water for handwashing to prevent the spread of disease.

The efficacy of interferon A (rIFN-α2A), an Escherichia coli-derived interferon, in the prophylaxis of acute upper respiratory tract infection, was evaluated in a community-based double-blind placebo-controlled study in the Australian winter of 1985. The trial population of 412 healthy volunteers (190 males and 222 females, aged 18–65 years) self-administered 1·5, 3·0 and 6·0 megaunits (MU) of interferon A per day or a placebo, intranasally for 28 days.

The period of study coincided with an outbreak of H3N2 influenza A (detected in 35 of the 107 acute specimens) as well as substantial numbers of respiratory syncytial virus and adenovirus infections. Rhinoviruses were isolated from only three specimens. In many cases, subjects had laboratory and clinical evidence of having had more than one respiratory tract infection during the period of the study. Viruses were detected in 54 or 107 acute specimens (49%).

No statistically significant differences were noted between the various treatment groups in the incidence of laboratory-proven viral infection (virus isolation and/or antibody response). Analysis of reported symptoms indicated that blood-tinged mucus and nasal stuffiness occurred more frequently with higher doses of interferon. There appeared to be no clinical benefit from the use of interferon A in the amelioration of symptoms.

The strain of methicillin-resistant Staphylococcus aureus (MRSA) prevalent in south-east England produced in one acute hospital in a year 40 infections (bacteraemia, pneumonia and surgical wound, skin and urinary tract infections) with three attributable deaths. Rigorous measures succeeded in controlling the outbreak despite its extent, but our results suggest that less stringent measures could fail to control outbreaks of this scale. Several subsequent localized outbreaks within the hospital, probably caused by separate re-introductions of MRSA from other hospitals, were controlled by re-instigation of control measures on individual wards. The overall success of the intervention was shown by the decline in the incidence of MRSA infections from 27 in the 6 months beforehand to 2 in the most recent 6 months, and by the decline in the prevalence of colonization among patients 10 or more days in hospital from 52% immediately before the intervention to 3% 7 months after it. The incidence of attributable morbidity and death without control measures warrants a concerted effort to tackle the epidemic in all affected hospitals in Britain.

Serratia marcescens was isolated in pure culture from cases of septic abortion in 4 cows on one farm and 10 buffaloes on two other farms. A reddish vaginal discharge was observed after abortion in all animals and in the internal organs of the aborted fetuses. All but two of the isolates produced prodigiosin, and two of the isolates from buffaloes were atypical in that they fermented raffinose. O-serological, bacteriophage and bacteriocin typing revealed four different strains. All cows were infected by the same strain, and this strain was also isolated from the semen of a breeding bull on the same farm. In another farm a strain of serotype O 14 was isolated from 6 of 10 buffaloes, and two other distinct strains were isolated from the remainder. The strain from the cattle was sensitive to gentamicin and so were two of the buffalo isolates. The infected cows were treated with intra-uterine gentamicin and the organism disappeared from cervical mucus after 3 days. Each animal after abortion showed a raised titre of agglutinating antibody to their respective isolate. A survey of 1172 healthy buffaloes and cattle gave an incidence of 1·8% with raised titres towards S. marcescens.

In-patients at a London hospital over one year from whom the south-east England strain of ‘epidemic’ methicillin-resistant Staphylococcus aureus (MRSA) was isolated were compared with in-patients with strains of methicillin-sensitive Staphylococcus aureus (MSSA). MRSA were virtually entirely hospital-acquired; isolates before 10'days were uncommon and related to recent previous admission. Thereafter first isolates occurred at a fairly constant daily rate of about 1·9 per 1000 in-patients. Acquisition of MSSA after more than 4 days in hospital occurred at a similar constant rate. Such strains were less likely to be penicillin-sensitive than strains isolated in the first 4 days after admission (11 vs. 22%) and were considered to be hospital-acquired. The single MRSA strain caused 40 infections in a year, about half of all hospital-acquired staphylococcal infections. Patients prescribed anti-staphylococcal antibiotics and patients with indwelling cannulae both had about a ninefold increased risk of acquiring MRSA. There was no reciprocal increase in MSSA infections after control measures had substantially reduced the number of MRSA infections.

Eighteen strains of Salmonella choleraesuis subsp. choleraesuis serovar Typhi (S. typhi) isolated from blood of patiens in Japan who had visited Indonesia and returned before the onset of typhoid fever were found to possess the H-antigen z66reported by Guinée et al. (1981) but had the naturally occuring H-antigen d. They were not lysed by any of the phages of the Vi phage typing system. After passage through semi-solid medium containing H-z66 antiserum, H-antigens of 11 of 18 cultures with H-z66 phage changed to H-j and those of 2 others to H-d, while the remaining 5 were immobilized. With cultures in the H-d or H-j phages, change of the H-antigens did not occur when they were cultured in semi-solid medium containing homologous H-antiserum. These phase induction experiments as well as colony examination of original cultures suggest that H-z66 phase is unstable and tends to change of H-antigen to H-d or H-j occured without difficulty probably represented a mixed population of cells in the H-z66 and H-d or H-j phases. Since none of 856 isolates from Japan or fromimported cases of typhoid fever from Southeast Asia other than Indonesia exhibited the H-z66 antigen, it was concluded that the focus of typhois fever caused by S. typhi in H–z66 phase was probably in Indonesia.