The incidence and clinical features of campylobacter enteritis were studied in a defined general practice population over a period of three years. Specimens of faeces were cultured from a representative sample of patients suffering from acute enteritis. Of 168 patients submitting a specimen to the laboratory 34 (20·2%) were positive for thermophilic Campylobacter species. The projected campylobacter infection rate varied from 5·4% per annum in infancy to 0·3% per annum in the 5- to 14-year-olds with a mean of 1·1% per annum for the whole study population.

During the same period campylobacters were isolated from 484 (14·9%) of 3250 patients suffering from acute enteritis whose general practitioners had sent faecal specimens to the laboratory, confirming the importance of this organism in the aetiology of acute enteritis in the community.

Good antibody responses usually follow infection with Campylobacter jejuni. A comparison of agglutination, complement fixation and immunofluorescence tests was done on 55 sera from 40 sporadic patients with diarrhoeal disease and positive cultures for C. jejuni. Results showed 82 % positive with immunofluorescence, 62 % by complement fixation but only 38 % by agglutination, using two reference strains COP and MEL as antigens. Overall 90 % of the 40 patients were positive by one or more serological tests. Paired sera from 15 patients showed a fourfold or greater rise in only five, confirming previous observations that antibody formation occurs early in the course of infection. Results also suggest that different test systems may be detecting antibodies of different specificities. Results confirm the value of serological tests, but further information on serotypes is required for selection of suitable reference strains.

The exotoxins produced by ten strains of C. ulcerans (two human, six bovine and two equine) have been studied. On the criteria of toxin–antitoxin neutralisation and immunoprecipitation tests using highly specific diphtheria and C. ovis antitoxins with crude toxic filtrates, (NH4)2SO4 concentrates, and partially purified chromatographic preparations of these, together with the presence or absence of inhibition of the action of staphylococcal beta-haemolysin, and the reaction produced when injected intradermally into rabbits, two toxins could be identified, namely diphtheria toxin and C. ovis toxin. There was no evidence for the production of a third toxin specific for C. ulcerans. Five strains produced both diphtheria and C. ovis toxins. In four diphtheria toxin predominated, but in the fifth C. ovis toxin predominated. Two strains produced only diphtheria toxin and two only C. ovis toxin, though there was good but not complete evidence that a third strain (Revell) also fell into this latter group. Considerable variation occurred in the concentration of each toxin and, where both were present, in the proportion of each.

Hospital outbreaks of severe gastroenteritis caused by multi-resistant Salmonellatyphimurium have occurred in a number of cities throughout India since 1977. The strains involved belong to phage types 66 or 122, or are untypable; the latter are derived from types 66 or 122 by acquisition of one or more of a number of temperate bacteriophages. Types 66 and 122 are closely related and react with the same phages of the S. typhimurium typing scheme.

A plasmid belonging to compatibility group FIme encoding resistance to ampicillin, chloramphenicol, kanamycin, streptomycin, sulphonamides, spectinomycin, tetracyclines, gentamicin and trimethoprim (R-type ACKSSuSpTGTm) is present in all of the multi-resistant strains. Several other plasmids have been identified including an SSu resistance determinant, a group I2, transfer factor and an R factor coding for resistance to kanamycin, streptomycin and sulphonamides which is compatible with plasmids of all the standard compatibility groups. These plasmids are only present in a proportion of the strains examined.

Examination of strains from other sources has identified a paediatric hospital outbreak in Saudi Arabia and a number of sporadic infections in Great Britain which have been caused by the same organisms. These studies show that, despite differences in phage type and plasmid content, this group of strains belongs to a single clone which has become widespread in India with some extension to other countries.

The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management.

On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers.

Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria. The Naegleria isolates were identified as N. lovaniensis, a species commonly found in association with N. fowleri.

Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools.

A number of scombrotoxin poisoning incidents which have recently occurred in the UK following the consumption of canned fish have been investigated. Symptoms are described and the relationship between the histamine content of incriminated samples and toxicity is discussed.

Twelve antimicrobial drugs were studied for their effect on the endogenous aerobic potentially pathogenic bacteria (Enterobacteriaceae, Streptococcus faecalis) in the intestines and on the colonization resistance (CR) of the digestive tract. Three subclasses of antimicrobial drugs could be recognized: (1) those which suppress the CR following low oral doses (rifamycin, penicillin V, cloxacillin, fenethicillin); (2) those in which the CR is suppressed only following relatively high oral doses (amoxycillin); and (3) those in which no obvious suppression of the CR was noticed even following substantial oral doses (nalidixic acid, cinoxacin, co-trimoxazole, oral cephalosporins, piv-mecillinam and doxycyclin). Some of the drugs in the third category were found to suppress endogenous Enterobacteriaceae (nalidixic acid, co-trimoxazole, piv-mecillinam and doxycyclin) and S. faecalis (doxycyclin) at dose levels at which they did not decrease CR.

The frequency distribution is presented of the Vi-phage types of Salmonella typhi and of the phage types of S. paratyphi A and S. paratyphi B, examined by the National Centres represented in the IFEPT from 1970 to 1974. The most common types encountered in this international study were A and E1 (= E1 a), as has been previously observed. There was, however, a wide range of types, many of which are characteristic of particular geographical zones. The occurrence of such types out of their habitual context indicates their ‘exotic’ origin, providing a useful clue to their probable source.

Plasmid-mediated chloramphenicol resistance appeared in epidemic typhoid fever for the first time during this period. It occurred in Mexico, India, Vietnam and Thailand, and has assumed important proportions. All the plasmids concerned belonged to compatibility group H 1. The study of this phenomenon continues, and the findings will appear in future reports.

Salmonella mbandaka was isolated from cattle on three dairy farms. The duration of infection was less than four weeks and none of the animals became clinically ill. The animals had all consumed a diet containing a vegetable fat supplement contaminated with S. mbandaka and this was shown to be the source of the infections. It is significant that a feed containing purely vegetable components was incriminated.

A selective membrane filtration medium is described for use in the rapid assessment of water quality in tropical countries where the incidence of faecal coliforms other than E. coli presents problems in the interpretation of results. The medium gives comparable results to MPN values obtained in the multiple tube dilution test using modified Gray's glutamate medium, and to membrane filtration counts obtained using M-FC broth and membrane-enriched Teepol broth, whilst differentiation of E. coli is enhanced.

The susceptibility to antimicrobial agents of 569 salmonella isolates collected in 1977–8 from patients in hospitals in Rome was tested. Fifty-nine per cent of all isolates were resistant to one or more antimicrobials. Resistance was most common to sulphathiazole, tetracycline, streptomycin, whereas colistin, gentamicin, tobramycin, trimethoprim-sulphamethoxazole and nalidixic acid were the most active in vitro.

Multiple resistance was most frequently found in strains of Salmonella wien and S. typhimurium (94% and 38% respectively).

A significant change in the resistance pattern of S. wien was observed between 1977 and 1978, with a significant increase of susceptibility to some antimicrobials in 1978.

Twenty-one R-plasmids transmissible to E. coli K12 were derived from 46 resistant strains of S. typhimurum.

In May 1980 an extensive outbreak of gastroenteritis occurred in a private school in the city of Rio de Janeiro. Examination of faeces and paired sera showed that this outbreak was caused by both rotavirus and a virulent strain of Shigella sonnei. In the first 19 stool samples collected seven (37%) had rotavirus only, six (32%) had Sh. sonnei only, while four (21 %) had both agents. Examination of the second and third stool collections revealed only the presence of Sh. sonnei. The 18 paired sera showed seroconversion for rotavirus in four cases (22%) and in seven cases (39 %) for Sh. sonnei. The overall attack rate of the disease was approximately 75 %, the nursery and kindergarten having higher attack rates. Students in all grades became sick at the same time, and the unimodal curve of the onset dates of symptoms indicates a common source outbreak. Evidence suggested a contaminated water supply.

An enzyme immunoassay, with phenol–water-extracted lipopolysaccharide (LPS) from Brucella abortus as antigen, was used to detect the class-specific antibody response in sera from 173 patients with B. abortus, B. melitensis or B. suis infection. Sera from 30 patients with salmonellosis, yersiniosis or tularaemia and from 25 healthy individuals served as controls. The B. abortus LPS antigen permitted a safe diagnosis of acute and chronic brucellosis with high IgM and rising IgG titres in sera collected in the acute stage of the disease, and with elevated IgG titres only in the chronic stage. The B. abortus LPS antigen also permitted a specific diagnosis with the exception of the high titres estimated in sera from patients with Yersinia enterocolitica 09 infection. The problem with that well-known reciprocal cross-reactivity was overcome by using two additional antigens: Y. enterocolitica 09 native and periodate oxidized and borohydride reduced LPS preparations. In sera from patients with brucellosis high titres were estimated against all three antigens, whereas in sera from patients with yersiniosis caused by serotype 09 high titres were measurable only with the B. abortus and the Y. enterocolitica native LPS antigens. These data suggest that the B. abortus and Y. enterocolitica 09 LPS share one antigenic determinant resistant to periodate oxidation and borohydride reduction, and that in addition the Y. enterocolitica 09 LPS has a determinant which is sensitive to periodate oxidation and borohydride reduction.

An IgM-antibody capture radioimmunoassay (MACRIA) was developed for the detection of IgM antibody specific for the human parvovirus-like agent B19. Diagnosis of infection with this agent by either antigen detection or antibody seroconversion had been made by counter-current immunoelectrophoresis (CIE) in 18 cases of aplastic crisis occurring in children with homozygous sickle-cell disease. The MACRIA described here gave positive results in 17 of these 18 cases; in the remaining case only an acute specimen taken from the patient during viraemia and late convalescent specimens taken 184 and 247 days after onset of illness were available.

The test was used to investigate 20 further cases of aplastic crisis in which neither viral antigen nor antibody seroconversion could be detected by CIE. Detection of virus-specific IgM permitted diagnosis of infection with this parvovirus-like agent in 17 of these cases. In the remaining three cases only single serum specimens taken late in convalescence, 82 days or more after the onset of symptoms, were available.

In addition to these 34 cases of aplastic crisis in which primary infection with this agent was diagnosed by MACRIA, seven cases of apparent ‘silent’ infection detected by CIE were investigated. The test permitted the discrimination between primary infection and re-exposure to the virus in six of these patients.

The use of this assay has added a considerable weight of evidence implicating primary infection with this parvovirus-like agent as an important cause of aplastic crisis in children with sickle-cell disease. Furthermore, MACRIA permits diagnosis of infection when only single serum specimens taken up to ten weeks after infection are available. Thus the use of this test will significantly facilitate the investigation of other clinical syndromes of presumptive infectious aetiology.

The single radial haemolysis (SRH) technique detected anti-B/HK/8/73 HA antibody rises in 59–85 % of paired sera from persons immunized with different influenza vaccines. In contrast, analysis of the same sera by the haemagglutination inhibition (HI) test indicated significant antibody rises in only 27–54% of paired sera. High levels of antibody were detected to influenza B/HK/8/73 and B/Singapore/222/79 viruses in post-immunization sera analysed by SRH, whereas the HI test indicated comparatively low geometric mean antibody titres. Most adults responded to immunization with influenza B virus by producing cross-reactive (CR) antibody which reacted with different influenza B viruses including the early isolate B/Lee/40.

Mice were immunized by three intraperitoneal and one intravenous injection of rubella haemagglutinin. Splenocytes from these mice were fused with the cells of a syngeneic myeloma cell line, and following culture for various periods of time, single-cell clones were derived by the technique of limiting dilution.

A total of 139 clones were derived from 13 parent hybrid cultures. To date, four of these cloned cultures have been propagated as ascitic tumours in mice. The preparation of IgG from ascitic fluid and labelling of this antibody with 125I is described. Results indicate that the use of labelled monoclonal antibodies as indicator reagents in solid-phase IgM antibody capture assays for the detection of rubella-specific IgM results in enhanced performance of these tests.

An outbreak of suspected infectious hepatitis in a primary school was investigated using sensitive diagnostic methods for hepatitis A. A total of 116 sera from children were tested for the presence of both IgM and IgG antibodies to hepatitis A (HAV). The results were compared to those obtained for samples from a control school. IgG antibodies were present in 45 % and 10% of the children in the outbreak and control schools respectively.

Antibody to cytomegalovirus (CMV) was sought in sera from Malta using immunofluorescence. Seven per cent of the infants, 36% of the school children, increasing to 100% of the adults aged over 40 years were found to have antibody. Most infection occurred in pre-school children and adults over 25 years of age. This pattern of antibody acquisition appears different from that described for other countries.