Mycobacterium marinum, formerly known as ‘Mycobacterium balnei’, is a free-living organism which causes disease in fish and occasionally in man. When such infections occur in man they are usually associated with some aquatic activity, e.g. swimming, fishing, boating and keeping tropical fish. For this reason, the organism has been called a ‘leisure-time pathogen’ by Feldman, Long & David (1974) and the disease a ‘hobby hazard’ by Heineman, Spitzer & Pianphongsant (1972).

Four hundred and sixty admissions for whooping cough to three hospitals between 1974–9 were reviewed. Many children had a long illness. More than half of them had severe or moderately severe coughing spasms and a quarter had pronounced feeding difficulties. The incidence of clinical pneumonia and convulsions was low and there were no deaths. The disease continues to be much more severe in infancy. There was some evidence that the disease declined in severity over the period studied. A number of factors including increased use of erythromycin may have contributed to this change.

A widespread epidemic of severe dysentery in Zaire and neighbouring Central African countries was caused by a multiply drug-resistant strain of Shigella dysenteriae 1. Early isolations were resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracyclines (R-type = ACSSuT). Later in the epidemic strains resistant to trimethoprim (Tm) became prevalent and a few strains resistant to kanamycin (K) or nalidixic acid were also isolated. All resistances except nalidixic acid were encoded by plasmids of incompatibility groups X (ACT) or I1 (ACSSuTTm) and the epidemic strain also carried an SSu plasmid and a number of cryptic plasmids. The Inc X plasmid from this epidemic is the same as that in Sh. dysenteriae 1 strains isolated in Somalia in 1976 whereas the epidemic strains from the Shiga outbreaks in Central America, 1969 to 1971, and Sri Lanka, 1979, carried plasmids of group B. This epidemic demonstrates that when a multiresistant strain includes resistance to trimethoprim, nalidixic acid is a suitable alternative therapeutic agent.

The purpose of this study was to assess the feasibility, acceptability and effect of an in-home water chlorination programme in a rural village. Previous studies at this site showed high levels of faecal coliforms in household water, high diarrhoea rates in children, and enterotoxigenic Escherichia coli and rotaviruses were the most common pathogens isolated from patients. Household water came from a pond and was stored in clay pots. No homes had sanitary facilities. A blind, cross-over trial of treatment of household water with inexpensive hypochlorite by a community health worker was carried out over 18 weeks among 20 families. Water in the clay pots was sampled serially, and symptom surveillance was done by medical students. The programme was generally acceptable to the villagers and no change in water use patterns were apparent. The mean faecal coliform level in the chlorinated water was significantly less than in the placebo treated samples (70 vs 16000 organisms/dl, P < 0·001). People living in houses receiving placebo treatment had a mean of 11·2 days of diarrhoea per year, and the highest rate of 36·7 was among children less than 2 years old. Diarrhoea rates were not significantly different among the participants while exposed to water treated with hypochlorite. We conclude that a low-cost programme of this type, which utilizes community resources, is logistically feasible, appears to be culturally acceptable in this setting, and can result in a marked reduction in water contamination. The lack of effect on diarrhoea rates suggests that improvement in water quality may affect morbidity only when other variables relating to faecal–oral agent transmission are ameliorated at the same time.

For many years strains of Escherichia coli belonging to particular serotypes (EPEC) were a common cause of outbreaks of infantile enteritis in Europe and North America. E. coli 0142. H6 was first isolated from infants with diarrhoea in Indonesia in 1960 and a further outbreak occurred in Mexico in 1965. Between 1967 and 1972 outbreaks of infantile enteritis caused by E. coli 0142 were reported in hospitals in Scotland, England, Northern Ireland and Eire. Sporadic cases occurred in Canada in 1972 and a further outbreak occurred in Arizona, U.S.A. in 1975. Strains from all these incidents were examined by biochemical and serological methods. Their resistance to antimicrobial drugs was determined and their resistance plasmids characterized; their plasmid profiles were visualized by agarose gel electrophoresis. The cumulative evidence suggests that strains isolated in the British Isles all belonged to a single clone and were related to those isolated in Indonesia, the U.S.A. and Canada. However, the strains from Mexico appeared to be unrelated. This study demonstrates that single clones of enteropathogenic E. coli may spread throughout the world, causing outbreaks of diarrhoeal disease and acquiring resistance to antimicrobial drugs.

The most widely used indicator of the sanitary quality of recreational waters is the coliform group of bacteria. Present techniques of coliform enumeration are imprecise, and this fact is too often overlooked in routine water quality surveys as well as in research efforts seeking quantitative relationships between coliform density and the health effects of recreational waters. To illustrate this point, three years of data gathered by the New York City Department of Health as part of their routine beach water sampling programme were re-analysed, taking the limited precision of each coliform estimate into account. Re-analysis showed 56·6% of the data were not significantly different (P > 0·05) from the standard being used. This large percentage of the data was of little value in determining the acceptability of the waters being sampled relative to the standard being used and thus represented a substantial waste of time and expense. Of the remaining data, half indicated acceptable water quality and half indicated unacceptable water quality relative to the standard. These three years of data, therefore, gave little information on the acceptability of the water quality at this location with respect to the standard being used. The data further suggest significant differences in coliform density within sample dates. It is recommended that in future water quality surveys, or in studies of the health effects of recreational waters as related to coliform density, emphasis should shift from maximizing the number of sample dates to maximizing the number of replicate determinations made per sample date.

Hospital infections caused by strains of Staphylococcus aureus non-typable (NT) by phages have occurred in three Spanish hospitals since 1981. Reverse typing allowed characterization of the strains in all three cases.

We describe a community outbreak of campylobacter enteritis associated with the consumption of untreated milk, apparently contaminated by two cows with campylobacter mastitis. The outbreak occurred in two phases. Strains of Campylobacter jejuni of the Penner serogroup complex 4, 13, 16, 50 and Preston biotype code 6100 were isolated from patients in both episodes and from the faeces of the cattle, milk filters, bulk milk and retail milk. Milk samples from two of 40 milking cows were found to contain C. jejuni, and the wheys from these two cows had high titres of antibody to C. jejuni detected by ELISA techniques.

A μ-capture ELISA was developed for detecting Mycoplasma pneumoniae specific IgM, and compared with an indirect immunofluorescent antibody (IFA) technique and an indirect ELISA. μ-capture ELISA and IFA compared well and were found to be the most sensitive assays. The IFA test can be completed in 2 h whilst the results of the μ-capture ELISA can be available in 24 h. Both tests are amenable to routine diagnostic use and have similar sensitivity. Indirect ELISA was found to be less sensitive and less specific, giving high assay values with several sera having undetectable M. pneumoniae CF antibody or CF antibody in low titre. Serum samples obtained from 11 patients at various times after M. pneumoniae infection showed maximum antibody levels within the first month by all assays, with a gradual fall in amount of IgM with time when assayed by μ-capture ELISA, a more gradual decline by IFA and hardly any decline with indirect ELISA. It was concluded that the indirect ELISA is unsuitable for the investigation of possible M. pneumoniae infection because the sustained high assay values with serum samples taken many months after infection, make interpretation of the test results very difficult.

Three influenza A (H3N2) reassortant whole virus vaccine strains with differing antibody-inducing capacities in hamsters were investigated morphologically and antigenically. Although initial measurements of virion circumference, from electron micrographs of vaccine preparations, suggested a relationship of small virion size with low immunogenicity, subsequent immunization with, and morphological investigation of, vaccine virions separated on sucrose gradients, failed to obtain populations whose antibody-inducing capacity clearly correlated with constituent virion density, size, morphology or integrity.

However, antigenic investigation using single radial haemolysis (SRH) and monoclonal antibodies revealed significant differences in antigenic specificity between the strains. Furthermore, a series of H3N2 isolates, derived using standard reassortment procedures, also showed differences in antigenic specificity in their haemagglutination-inhibition (HI) reactions with monoclonal antibodies after five passages in allantois-on-shell cultures. Variation between these isolates and their A/Victoria parent virus could be detected using SRH and hamster sera raised against each isolate.

These results demonstrate variation between candidate influenza A virus vaccine strains, all possessing the same surface (H3N2) glycoproteins, expressed as a consequence of the reassortant system used for their production.

Five hundred and seventy-one camel sera collected after an epizootic of Rift Valley Fever were examined for antibody to the virus. Clinical disease had not been observed in cattle and sheep in the ecosystems shared with the camels. Positive sera with high titres of serum neutralizing antibody were found in 22% of camels at one of the seven sampling sites.