Despite advances in health care in the tropics, and the inputs of international and voluntary organisations, famine and disaster continue to cause major devastation in many developing countries. In the aftermath of acute disasters such as earthquakes or cyclones and in chronic post-famine relief camps, mortality rates may be 20–30 times greater than those in ‘normal’ years [1]. The interaction of malnutrition, crowding, poor environmental sanitation, and changes in host parasite relationships due to migration or environmental change, result in communicable diseases playing a major role in excess morbidity and mortality.

The use of ribosomal RNA (rRNA) gene restriction patterns to study the molecular epidemiology of Neisseria meningitidis was investigated. Ninety-four isolates of Neisseria meningitidis were characterized by their rRNA gene restriction patterns with 16 + 23 S rRNA from Escherichia coli as a probe. Thirteen rRNA gene restriction patterns were recognized; each of these patterns represented between 1 and 30 isolates. Isolates with the outbreak-associated phenotype B15P1.16 (sulphonamide resistant) all gave a single rRNA gene restriction pattern but this pattern also contained isolates with other phenotypes. Further discrimination between isolates was achieved by comparison of banding patterns resulting from restriction endonuclease digestion of chromosomal DNA with Bgl II. This gave a banding pattern consisting of about ten bands which was simple to interpret. Using this technique 94 isolates were classified in 54 patterns containing between 1 and 14 isolates. Restriction endonuclease analysis with Bgl II characterized outbreak-associated isolates with the phenotype B15P1.16 and enabled strains not typable by conventional methods to be identified as probable outbreak-associated isolates. The techniques should prove useful for epidemiological studies.

Restriction digest fragments of DNA from 46 clinical isolates identified as Corynebacterium group D2, were separated by electrophoresis, Southern blotted onto nylon membranes and hybridized to a ribosomal RNA gene probe. The resulting band patterns were subjected to unweighed pair-group cluster analysis. Representative strains from the main clusters were compared with similarly prepared band patterns from type strains of human Corynebacterium species.

The results indicate that strains identified as Corynebacterium group D2 represent a unique taxon and that computer-assisted analysis of rRNA gene restriction fragment polymorphism (ribotyping) could be a useful technique in epidemiological studies of these bacteria.

Recovery from disseminated candidosis is associated with seroconversion to a 47 kDa breakdown product of the Heat Shock Protein (HSP) 90 of Candida albicans. Cloning, sequencing and epitope mapping has allowed the delineation of the immunodominant epitopes LKVIRKNIVKKMIE and STDEPAGESA. Monoclonal and polyclonal antibodies specific to these epitopes are used to show that all strains of C. albicans tested produce HSP 90 in both the yeast and mycelial phases. Homologous proteins are demonstrated in Saccharomyces cerevisiae, Candida parapsilosis and Corynebacterium jeikeium but not in Torulopsis glabrata. Evidence is presented for the existence of two distinct HSP 90s in C. albicans. The first of these is expressed constitutively whilst the second is produced on heat shocking the yeast from 23 to 37 °C.

An enzyme-linked immunoassay (ELISA) has been developed to detect serum Immunoglobulin antibodies G and M to Treponema hyodysenteriae in vaccinated, experimentally infected and naturally infected swine. Naturally infected swine gave ELISA titres that were similar to experimentally infected swine, but were significantly less than the titres of vaccinated swine. When serum from naturally infected swine was used to probe nitrocellulose blots of sodium dodecyl sulphate–polyacrylamide gel electrophoresed whole cell proteins of T. hyodysenteriae, the immunoblotting patterns showed IgG antibodies were produced against many T. hyodysenteriae protein antigens and against lipopolysaccharide (LPS). The IgG antibodies directed against LPS were serotype-specific for that LPS and could be used to identify the serotype involved in the T. hyodysenteriae infection in that herd. IgM immunoblots also reacted with the many protein antigens but were less specific for LPS antigen, with a substantial degree of crossreaction between the LPS of all serotypes.

The data demonstrate that a microplate enzyme-linked immunosorbent assay, coupled with immunoblotting, is a very specific and sensitive test for detection of antibody to Treponema hyodysenteriae in swine.

DNA- fingerprints (Hind III) of Streptococcus uberis field isolates from New York State and Europe showed substantial homogeneity, but were different to those of the type strain of the newly proposed psychrophilic species S. parauberis. S. uberis strains had major SDS-heat extracted antigens of molecular masses (Mr) < 14, 40–41, 42–43, 59–61, 80–86 and 118–122 kDa following immunoblotting with rabbit hyperimmune sera. Bovine sera and milk reacted with the 40–41 and 118–122 kDa antigens. Variations in the Mr of particular bands were too unevenly distributed to permit formation of subgroups. Although cross reactive, the sizes of the antigens of S. parauberis strain NCDO 2020 were substantially different to those of S. uberis, the most prominent antigen having a Mr of 50 kDa. The antigenic and genetic data therefore strongly support the introduction of S. parauberis as a distinct species. S. uberis strains reacted with antiserum to Lancefield groups B, E, G and P, their grouping reactions showing no correlation with DNA and immunoblot fingerprints. Lancefield grouping of S. uberis therefore appears to have little value in identification.

The PhenePlate (PhP) biochemical fingerprinting system is an automated method for typing of bacteria, based on the evaluation of the kinetics of biochemical reactions, performed in microtitre plates. In the present study the PhP-Klebsiella/Enterobacter (KE) system was evaluated for typing of Enterobacter cloacae and employed to study the epidemiology of faecal E. cloacae strains isolated from infants in 22 Swedish neonatal wards. The PhP-KE system showed a high reproducibility and discrimination for E. cloacae isolates. Among 64 epidemiologically unrelated E. cloacae strains, 49 distinct phenotypes were found, and the diversity index was 0·985. E. cloacae was found as a part of the dominating Gram-negative aerobic bacterial flora in 83 out of 953 infants studied. The incidences of E. cloacae colonization varied between 0 and 35% in different wards, but in contrast to previous data for Klebsiella spp. and Escherichia coli, there was little evidence of spread of particular strains in the wards. We also discuss two different measures of nosocomial transmission of bacterial strains: transmissible strains and epidemic index.

A total of 123 drug-resistant and drug-sensitive Shigella flexneri types 1–6, and their Escherichia coli K12 transconjugants were used for plasmid profile analysis by agarose gel electrophoresis. Resistance factors (R-factors) were further characterized by incompatibility testing.

The overall distribution of small plasmids in S. flexneri showed that a cryptic plasmid of about 4·6 Kb was found in all serotypes, and a plasmid of about 4·2 Kb was found in serotypes 1–4. Shigella flexneri types 2, 4 and 6 showed a 6·5 Kb plasmid which correlated with SSu-resistance. All S. flexneri serotypes harboured large plasmids of about 217 Kb. Plasmid profile analysis of S. flexneri in Ethiopia showed a high degree of uniformity within individual serotypes. However, there was a limited variability which, at times, could be useful for epidemiological investigation. Shigella flexneri serotypes 1–6 harboured resistance plasmids with diverse molecular weights but mostly belonging to incompatibility groups N and X.

This study presents the findings of a national survey of 1482 cases of salmonellosis reported to Environmental Health Departments in England and Wales between August 1988 and March 1989. A questionnaire survey of ill individuals and the environmental health officers who investigated them sought information about costs which were imposed upon public health authorities, the health sector, individuals and their families and the costs to the wider economy in terms of lost production.

Costs of £996339 were identified. Over half (£507555) resulted from lost production due to sickness absence and more than a third (£392822) were costs to the public sector which resulted from health care and local authority investigation of cases. The remaining costs (£95962), although the smallest proportion of the total, indicated that salmonellosis can have a significant impact on affected individuals and their families.

Sera from patients with yersiniosis. shown to contain antibodies to Yersinia enterocolitica O9; and sera from patients with haemolytic uraemic syndrome (HUS) caused by Escherichia coli O157, were used to investigate serological cross-reactions between Y. enterocolitica O9 and E. coli O157. Lipopolysaccharide (LPS) was isolated from strains of Y. enterocolitica O9 and E. coli O157 and reacted with sera by immunoblotting and ELISA. Sera from patients with HUS contained antibodies to the LPS of E. coli O157 only; 80% of sera from patients with yersiniosis contained antibodies to the LPS of Y. enterocolitica O9 and E. coli O157. This one-way cross-reaction was also detected using hyperimmune rabbit antisera.

A total of 221 cockroaches (Blatta and Periplaneta spp.), collected in hospitals, houses, animal sheds, grocery stores and restaurants, in yarious parts of South Kanara District, a south-west coastal region of India, were studied bacteriologically for the presence of various salmonellas. Salmonellas were isolated from 4·1% of these cockroaches. Nine strains of salmonellas were recovered, belonging to five serotypes – Salmonella bovismorbificans, S. oslo, S. typhimurium, S. mbandaka and S. braenderup, the former two being the commonest serotypes. All salmonellas were resistant to one or other of 11 antibacterial drugs used in the susceptibility test. Isolation of salmonellas from cockroaches collected from the livestock premises and human dwellings suggested that they may act as significant reservoirs of salmonella in nature. Recovery of serotypes, phage types and R- types that were commonly isolated from humans and animals of this locality, suggested a transmission role for cockroaches. By harbouring potentially pathogenic, drug-resistant salmonellas, these wandering arthropods may pose dangerous infective hazards to humans and animals.

In 1990 we reported that milk bottles pecked by jackdaws and magpies were a probable source of human Campylobacter infection. During April to June 1990 an extended study of Campylobacter infections was carried out in the Gateshead area. Prior to the study a health education programme was undertaken in an attempt to reduce human infection. Fifty-nine cases of human infection were recorded and 52 were interviewed. Thirty were entered into a case control study which demonstrated a very strong association between consumption of pecked milk and human Campylobacter infection (X2 = 12·6, P < 0·0004). It was estimated that between 500 and 1000 jackdaws (Corvus monedula) were present in the area where milk bottles were pecked and 63 isolates of Campylobacter were made from the bill and cloaca. Target bottles were put out in the early mornings and Campylobacters were isolated from 12 of 123 pecked bottles. Typing of the Campylobacters revealed a wide distribution of strains amongst birds, pecked milk and human infections. The health education programme had only limited success.

An outbreak of infection caused by a previously undescribed Gram-negative bacterium affected people attending a hot (37 °C) spring spa in France in 1987. Thirty-five case of pneumonia and two cases of meningitis occurred. None of these patients died. Attack rates were significantly higher for patients above 70 years old and for male patients. An epidemiological comparison of the 26 hospitalized eases with 52 matched controls suggests that spa treatment early on the first day (OR = 4·8) and attendance at the vapour baths (OR = 10·7) were significant risk factors for acquiring the infection. Person-to-person spread was not thought to have occurred. The same bacterium was isolated from the hot spring water. All strains studied shows a single rRNA gene restriction pattern. Epidemiological data indicated that the thermal water was the source of infection. This outbreak stresses the need for increased surveillance of infections in people attending hot spring spas.

The morphology of faecal microflora of nine healthy human volunteers was studied by digital image analysis of microscopic slides. Weekly specimens were collected during an 8-week period. Seven morphometrical parameters were derived: the means and medians of components 1, 2 and 3, and morphometrical entropy. Statistically significant differences among subjects were found for means of components 1 and 2, medians of components 1, 2 and 3, and entropy. The stability in normal circumstances provides an excellent basis for the detection of pathological change in gut flora balance.

The relationship between visual inspections carried out by environmental health officers and microbiological examination was studied in 89 restaurants. Using 30 variables a standardized inspection procedure was developed and each of the premises was assessed in six main areas – structure and design, cleaning and cleanliness, personal hygiene, risk of contamination, temperature control, and training and knowledge about food hygiene. Selected foods and specimens from hands, surfaces, and wiping cloths were examined. There were significant associations between all six areas of the inspections. The structure and design were significantly related to the combined score from all the other areas (P < 0·001). There were no highly significant associations between microbiological examination and visual assessments. The microbial contamination of wiping cloths, however, was related to the cleaning and cleanliness (P = 0·005). Microbial sampling provided additional information to inspections and was a valuable aid. Further development of this risk-assessment approach could provide an effective system for monitoring potential health risks in high-risk food premises.

We have developed a nucleic acid dot-blot hybridization test for the detection of astroviruses in stool samples. The test was not as sensitive as electron microscopy for the detection of low numbers of well preserved astrovirus particles, but was able to identify astroviruses in stools containing particles of indistinct morphology. In total, this procedure identified astroviruses in more samples than did electron microscopy, and the data indicate that the incidence of astroviruses may be substantially underestimated.

Numerous investigators have reported an increased incidence of pneumonia caused by Gram-negative bacilli and other secondary pathogens in transplant recipients infected by cytomegalovirus (CMV). To determine if CMV infections are related to colonization of the upper respiratory tract by Gram-negative bacilli, we examined prospectively 22 renal transplant recipients with sequential bacteriological, virological and biochemical examinations performed just prior to and at various times after transplantation. Only 11% of subjects had Gram-negative bacilli isolated from gargle specimens prior to transplantation, as compared to 54% after transplantation. More importantly, after transplantation, subjects with active CMV infections were more likely to have prolonged oropharyngeal carriage of Gram-negative bacilli than subjects without CMV infections (36% v.. 25%). During active CMV infections, the rate at which Gram-negative bacilli were isolated from gargle specimens rose from 28 to 47%. During culture-positive CMV infections, the isolation rate reached 57% and was significantly different from that of CMV-negative samples (P < 0·01). The increased rate of Gram-negative bacillary isolation from gargle specimens during CMV infections was not a function of type of immunosuppresive agents used, rejection episodes, antibiotic administration, concomitant hepatitis B, Epstein–Barr (EBV) virus, or herpes simplex virus infections, or alterations in salivary fibronectin concentrations.

Between 1987 and 1989, the prevalence of antibody to cytomegalovirus (CMV) was determined, by the ELISA method, in serum samples from 1494 apparently healthy subjects, 3–18 years old. Subjects were selected by a systematic cluster sampling from five geographical areas in Italy. The overall prevalence of antibody was 64·2%, increasing from 54·4% in 4–6-year-olds to 73·3% in subjects 17–18 years old (P < 0·01). Prevalence of antibody was significantly higher in females (P < 0·05) and in subjects residing in the South of Italy (P < 0·01). A significant association was found with sociodemographic factors. Subjects belonging to a household with six or more persons had a 1·5-fold risk (C.I. 95% = 1·11–2·04) and subjects whose fathers had less than 6 years of schooling had a 1·4-fold risk (C.I. 95% = 1·1–1·87) of previous exposure to CMV infection. The high prevalence (74·4%) of young women who are naturally immune when entering childbearing years does not guarantee that there will be a low risk of fetal infection.

The prevalence of antibodies to human T-cell lymphotropic virus type I (HTLV-1) was determined in high-risk groups and normal adults in Egypt. Among 647 individuals tested, 6 (0·9%) were confirmed positive by western blot analysis. These included 2 (0·7%) of 279 drug addicts, 1 (3·3%) of 30 patients with sexually transmitted diseases, and 3 (2·2%) of 133 healthy individuals. Antibody was not detected in 47 blood recipients or 158 prostitutes. There was no correlation between sex or geographical location and HTLV-I infection. Fifty-three of the 647 sera (8%) were initially reactive by ELISA, but only 12 sera were repeatedly reactive. Since only 4 of these repeatedly reactive sera were confirmed by the western blot, the frequency of false positives using the DuPont screening ELISA was 1·2% (8/643). Two additional sera, confirmed positive by western blot, had been reactive, but not repeatedly, by ELISA. In comparison to the prevalence of HTLV-I antibody among risk groups in many parts of the world, the prevalence in Egypt was low.

Duplicate neutralization tests were done on 401 avian and 101 human sera from island residents collected in the Coral Sea and on Australia's Great Barrier Reef against 19 known arboviruses. Antibodies to a potentially harmful flavivirus, Gadget's Gully virus, were equally present (4%) in both avian and human sera. Antibodies to another flavivirus, Murray Valley Encephalitis, and an ungrouped isolate, CSIRO 1499, were also present in both populations with non-significantly different incidences. Antibodies to Upolu, Johnston Atoll, Lake Clarendon, Taggert, Saumarez Reef and CSIRO 264 viruses were restricted to seabirds. Island residents with antibodies to Ross River and Barmah Forest viruses are thought to have been exposed to these viruses on the mainland as antibody to both viruses was absent among seabirds. These results indicate that consideration should be given to tick-associated arboviruses as potential public health hazards on islands where both seabird and human activities interact.