A 10 min education programme was developed which, if effective in changing the behaviour of pregnant women, would eliminate or greatly reduce the risk of congenital toxoplasmosis. It was taught in 26 randomly selected (case) prenatal classes offered to women early in their pregnancy. The remaining 26 (control) classes received routine class material which did not mention toxoplasmosis. A questionnaire was administered to all women prior to this early class (pre-test) and again after the last prenatal class, held just prior to delivery (post-test). Changes in pet, food and personal hygiene behaviour between the pre- and post-test were determined and a score calculated by adding points for change towards those behaviours recommended in the programme and subtracting points for change in the opposite direction. Cat owners in case classes had a significantly higher score in pet hygiene behaviour than those in control classes (P < 0·05). No significant difference was found between the food or personal hygiene scores of women in case and control classes, possibly because of low power. However, although behaviours did not differ on the pre-test, women in case classes had significantly better cooking methods for roast beef and hamburger on the post-test (P < 0·05 and P < 0·01 respectively). It is concluded that this programme is effective and should be offered to all women in order to reduce congenital toxoplasmosis incidence.

Antibody titres toStreptococcus suis type 2 were measured with an enzyme linked immunosorbent assay (ELISA) in four occupational groups in New Zealand. No veterinary students, 9% of dairy farmers. 10% of meat inspectors and 21% of pig farmers were seropositive to S. suis type 2. The development of antibody to S. suis type 2 was associated with occupational contact with pigs or their meat products. Subclinical infection withS. suis type 2 appears to occur in humans and the antibody produced is of only short duration. The annual incidence of subclinical infection and seroconversion in pig farmers may approach 28%. ThusS. suistype 2 may be one of the most infectious potentially zoonotic agents present in New Zealand, although very rarely resulting in clinical disease.

A new epidemiologic typing method based on electrophoresis of esterases had been developed for differentiating between clinical isolates of Branhamella catarrhalis. Twenty-two epidemiologically significant strains obtained from three Chest Units, a Paediatric Intensive Care Unit and a Paediatric Unit were compared with 54 randomly selected strains and 4 reference strains, including the species type strain, ATCC 25238. Thirty-four distinct zymotypes were characterized by polyacrylamide-agarose gel electrophoresis of the 80 strains. One infrequent zymotype was found in 2 neonates and another in 2 adults with nosocomial bronchopulmonary infections, suggesting the nosocomial spread of 2 outbreak strains of B. catarrhalis. A more frequent zymotype was isolated from 3 neonates with nosocomial bronchopulmonary infection and from 2 children with nosocomial rhinopharyngitis. The remaining 12 epidemiologically significant strains were of varied zymotypes. This work demonstrates that esterase electrophoresis is a suitable, readily reproducible, stable typing system applicable to the wide range of strains found in B. catarrhalis nosocomial infections.

A simple and reproducible typing system based on restriction fragment size of chromosomal DNA was developed to compare isolates of Streptococcus uberis obtained from the bovine mammary gland. The endonuclease giving the most useful restriction patterns was Hind III, although seven other endonucleases (Bgl 1, Eco R1, Not 1, Pst 1, Sfi 1, Sma 1, Xba 1) were also tested in the system. An image analyser was used to obtain a densitometric scan and a graphic display of the restriction patterns. Such a system will allow large scale data storage for future computer-aided comparison.

In the spring term of 1985 there was a protracted outbreak of upper respiratory tract febrile illness consistent with a clinical diagnosis of influenza in a boys' boarding school, which lasted from 23 January to 29 March. Although influenza virus infection was confirmed in 89% of cases in the first half of the term, 53% of the cases which occurred in the second half of the term had no evidence of infection with influenza virus. Between 5 February and 31 March 28 boys presented with skin rashes consistent with a clinical diagnosis of erythema infectiosum; 68% of these were associated with parvovirus B19. Investigation of the cases of clinical influenza with no identified respiratory pathogen revealed a 58% infection rate with B19. B19 DNA was identified in either throat swabs or acute stage bloods of nine pupils with influenza-like symptoms.

Cohort studies revealed that 44% of pupils aged 15–16 years were immune before the outbreak compared with only 17% of pupils aged 11–12 years. Infection in the younger group was common and was associated with influenzalike illnesses as well as rashes. Forty-eight per cent of those who did not report any symptoms were also infected with B19.

In March 1988 a general practitioner notified two cases of hepatitis A in a private boarding school. Epidemiological investigation, including testing for salivary antibodies revealed a further five cases and established immunity to, and recent infection with, hepatitis A virus (HAV). The pattern of the outbreak was described. A number of practices which would encourage cross-infection were corrected. Normal human immunoglobulin was given to contacts.

Repeat salivary testing 10 weeks later revealed that two more boys had becomereactive for anti-HAV, though at a low titre. These may have been serologicalresponses to HAV infection modified by the passive immunization.

Nosocomial infection or colonization due to enterococci with high-level resistance to vancomycin (minimal inhibitory concentrations [MICs] between 64 and > 2000 mg/L) has occurred in 41 patients with renal disease. These vancomycin-resistant enterococci were cultured from many sources including blood. All but one strain contained one or more plasmids ranging in molecular weight from 1·0 to 40 Megadaltons (MDa). Vancomycin resistance was transferable by conjugation to a susceptible recipient strain of Enterococcus faecalis but this was not always associated with plasmid DNA. The emergence of transferable high-level vancomycin resistance in enterococci causing significant clinical infections is of particular importance since vancomycin is widely regarded as a reserve drug for the management of infections with multi-resistant Gram-positive organisms.

Three hundred and fifty-eight stool and 131 sputum specimens from 40 cystic fibrosis (CF) patients and 100 toilet sinks were investigated for occurrence of Pseudomonas aeruginosa; 67% (21/31) of the patients with chronic P. aeruginosa lung infections carried the organism repeatedly in the stool but the organism was found only once in the stools of nine uninfected patients. P. aeruginosa stool carriage was correlated to high P. aeruginosa numbers in patients' sputa. Typing of P. aeruginosa with a DNA probe showed identity of sputum and stool strains. Seven patients repeatedly carried additional stool strains, not found in the sputum, suggesting intestinal colonization. No differences were seen in the clinical state of patients with P. aeruginosa-negative stool samples and patients with positive stool samples. Toilets in households of P. aeruginosa-infected CF patients were significantly more often contaminated with P. aeruginosa (42%) than toilets in households of non-infected CF patients (20%; P < 0·03). The study shows that P. aeruginosa-infected CF patients may harbour the organisms also in the intestinal tract, and may spread the bacteria into toilets.

A series of clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) from two hospitals in China was examined. Fragment patterns obtained by digestion of total cellular DNA with restriction enzymes were used to characterize the isolates, in combination with phage-typing, antibiotic resistance profile, and plasmid profile. Digestion of total cellular DNA with restriction enzymes was most useful in discriminating between isolates and yielded additional information on the relatedness of non-identical isolates. In one hospital a single strain, resistant to a large number of antibiotics, had apparently become endemic. In the second hospital a number of distinct but related strains were present. The isolates were also related but not identical to the strain of MRSA endemic at the London Hospital.

A total of 1786 blood donors were screened for the presence of anti-hepatitis A antibod (anti HAV). 64·5% of the donors were found to be positive. The prevalence of the antibody was found to be age-related, 55% at 18 years and 75% at 65 years. No relationship was noted between the presence of antibody, foreign travel or a specific destination. Assay of antibody levels in selected seropositive individuals gave a mean level of 5· IU/ml.

The prevalence of infection in this selected population is important in thecontext of passive immunization with normal human immunoglobulin and for defining a policy of immunization with hepatitis A vaccines, which are currently undergoing clinical trials.

A survey was made of serotype association and multiple antibiotic resistance in strains of Pseudomonas aeruginosa in Europe. Of 208 epidemiologically distinct strains from 16 laboratories in 10 countries, 48 were resistant to carbenicillin (MIC > 128 μg/ml) and gentamicin (MIC > 4 μ g/ml), and 12 of these strains were of serotvpe O 12. Representative O 12 strains from different countries were compared with two multiresistant O 12 strains isolated 5 years apart, from a British burns unit and the antibiotic sensitive serotype reference strain. All O 12 strains were similar by phage and pyocin typing but lysogenic phage profiles indicated that two strains (the later burns isolate and the serotype strain) were distinct from the others. Electrophoretic characterization of outer membrane proteins, lipopoly- saccharides and esterase enzymes corroborated the relationship of the strains and restriction fragment length polymorphism of DNA fragments hybridized with a cDNA probe copy of rRNA from P. aeruginosa provided further proof of their relatedness. We propose that the uniformity of characters of multiresistant O 12 P. aeruginosa in Europe is suggestive of a common origin for the strains.

Firemen have been considered at occupational risk of hepatitis (HBV) infection, but proof is lacking. The aim of this study was to assess the degree of risk by determining the prevalence of serological markers of past infection with HBV in members of the West Yorkshire Fire Service. Sera from 173 firemen, 9·3% of the brigade, were tested for antibodies to HBV surface antigen and to core antigen. Those containing anti-HBs≥10 IU/L or anti-core antibody, were also tested for antibody to HBe antigen. The presence of more than one marker was used to define past infection. One sample satisfied this criterion, giving a prevalence rate of 0·6%. This compares with a rate of 1% in London blood donors. We conclude that the group shows no evidence of having been at increased risk of HBV infection. A comprehensive vaccination policy for firemen might be questionable

A total of 108 raw water samples was collected from 36 wells at nine shanty settlements around Port Harcourt, Nigeria, over a period of 7 months. Samples were analysed for their bacteriological quality. Selected bacterial strains isolated from the samples were tested for their susceptibility to ten commonly used antibiotics. The organisms isolated include Pseudomonas spp., Klebsieila spp., Staphylococcus spp., Proteus spp., Enterococcus faecalis, Aeromonas spp., Escherichia coli, Chromobacterium spp., Flavobacterium spp., and Serratia spp.

Out of 300 strains tested, 23 (6·9%) were susceptible to all the antibiotics, 277 (92·3%) were resistant to at least one antibiotic and 232 (77·3%) were resistant to two or more antibiotics. The epidemiological significance of these results is discussed.

Graded doses of live and heat-killed cells of Campylobacter jejuni were injected into the yolk-sac of 5-day-old chick embryos, and the 50% lethal dose (LD50) was determined 7 days later. A strain dependent virulence was seen. In the diluted series of cultures the LD50 values for live campylobacter ranged from 106 c.f.u. beyond the last dilution showing growth, that is to less than one organism per embryo. When the 22 strains were tested as heat-killed cells, the chick embryo LD50 values retained the same relative order of toxicity obtained with viable cells, but the LD50 values were increased by + 1 to + 4 log units. Heat-killed cells from strains known to be invasive, but non-toxigenic, were still lethal for the embryos, suggesting that viability was not solely necessary for virulence. Semi-pure lipopolysaccharide from a non-virulent strain of C. jejuni was not toxic to the embryos, but semi-pure and ultracentrifuge-purified lipopolysaccharide from the most lethal campylobacter strains gave LD50 values in the order of 3·0 μg lipopolysaccharide per ml (0·6 µg per embryo) in the yolk-sac assay. No relationship between serotype and lethality was seen. Injection into the yolk-sac appears to be an easy, rapid and reproducible in vivo assay of the virulence of C. jejuni.

A total of 160 consecutive isolates of Neisseria gonorrhoeae was collected over a 3-month period. They were tested for their susceptibility to penicillin, erythromycin and spectinomycin and the auxotype and the serotype determined. We have evaluated two sampling methods, the collection of every fifth isolate and the first 20 isolates (10 male and 10 female) each month, to determine whether either is representative of the total population. There was no significant difference between either method of sampling and the total for detecting the predominant auxotypes and serovars or the distributions in antibiotic susceptibility. It is possible to monitor major changes in a gonococcal population, particularly susceptibility to antibiotics, using a sample of the total population.

The efficacy and acceptability of yeast-derived recombinant hepatitis B vaccine given by the intradermal route was investigated in 221 health care volunteers. Two hundred and sixteen received a full course of three doses of vaccine. Only one subject was withdrawn because of a significant adverse reaction (psoriasis). The vaccine stimulated an antibody response in 81%. The response to the vaccine was better in women than in men (87% compared with 71%, p = 0·007) and in women below the age of 40 years compared with older women (94% compared with 76%, p = 0·01). For men the response showed a sequential decline with age for each decade (90% responders from age 29 or less, 72% aged 30—39 and 65% aged 40 or more, p = 0·04). Retrospective enquiry showed that over 90% had found the intradermal route acceptable and 59% would prefer vaccine by the intradermal route in preference to intramuscular notwithstanding local reactions. Although the seroconversion rate was of a high order in younger women the antibody titres were not high with only 9 of 215 recipients developing titres >1000 mIU/ml, a level which could be expected to ensure prolonged immunity. A fourth intradermal dose of vaccine given to 60 volunteers who had shown a low response (<38 mIU/ml) or no serological response to a three-dose course stimulated a good booster effect (to 150—600 mIU/ml) in only 5 (8%).

The diphtheria immunity status was determined with the passive haemagglutination technique in 503 sera of 10–90-year-old persons from Warsaw and Olsztyn Provinces. Donors of sera were students, teachers, pregnant women, employees of industry and medical service. The immunity was highest (90% of titers 0·1 lU/ml or higher) in persons below 20 years of age and in persons above 60 years of age (55%). Between these two groups, gaps in immunity exist, the proportion of those immune varying from 36–50% in the 20- 60-year-old groups.

The outer membrane proteins of 38 Yersinia pestis isolates from all known plague foci of north-east Brazil were analysed by SDS-PAGE. Approximately 20 bands were consistently found in all strains analysed and 11 were selected for comparative studies. Although qualitative differences among the electrophoretic profiles of outer membrane proteins of wild Y. pestis isolates were not observed, quantitative alterations were clearly noted for most of these proteins. No particular quantitative alteration of the electrophoretic profile of outer membrane proteins could be associated with the period of isolation and geographic origin of the isolates. The 64 kDa outer membrane protein was significantly expressed in higher amounts among Y. pestis strains isolated from a recent plague outbreak. The possible use of electrophoretic profiles of outer membrane proteins of wild Y. pestis isolates as a tool for epidemiological studies and for the analysis of virulence determinants is discussed.

Sera from an outbreak of acute respiratory illness in a boys boarding school originally thought to have been due to psittacosis (1) have been re-examined and evidence is presented that suggests that the outbreak was caused by Chlamydia pneumoniae, strain TWAR (2).

The study arose from the recent finding that sub-lethal numbers of certain bacterial species greatly enhanced the infectivity of Fusobacterium necrophorum.

A severe F. necrophorum infection in mice, cured with metronidazole, produced significant though slight resistance, which was demonstrable by challenge with a minute dose of F. necrophorum (< 20 organisms) suspended in a sub-lethal dose of Escherichia coli (300 × 10 organisms) to enhance fusobacterial infectivity. In an earlier comparable experiment, challenge with F. necrophorum alone, in necessarily large doses (≥3 × lO organisms), failed to demonstrate that a single cured fusobacterial infection gave rise to resistance; such an infection neither protected against the fatal necrobacillosis produced by challenge nor prolonged survival.

A sub-lethal E. coli infection was also shown by challenge with a minute dose of F. necrophorum (< 10 organisms), suspended in a sub-lethal dose of E. coli (152 × 10 organisms), to produce significant though slight protection against necrobacillosis.

The degrees of resistance demonstrated were too slight to give any encouragement to the prospect of an effective necrobacillosis vaccine.