There are few applications of virology to clinical medicine that have received more attention than the laboratory diagnosis of rubella. Many laboratories attempt it and most readers of this journal will be familiar with the techniques that have been used. It would therefore be superfluous to review the ‘state of the artm’ had there not recently been an innovation that is likely to alter laboratory practice in this field.

An inhibitor ‘fingerprinting’ technique was used to test 120 group B and 50 group C streptococcus strains for production of inhibitory activity. The incidence of inhibitor production was low. Five of 70 group B streptococci of animal origin and one of 50 from human sources consistently produced inhibitory activity. Six of 20 animal strains and three of 30 human strains of group C streptococci were inhibitor producers. These included two Streptococcus dysgalactiae, three S. equisimilis and four S. zooepidemicus.

The temperature of incubation and species of origin of the blood used in the culture medium were critical determinants of inhibitor production. Investigation of inhibitors for their spectrum of activity, heat stability, sensitivity to trypsin, dialysability and mode of action indicated that five of the group B and seven of the group C streptococci produced inhibitors that had bacteriocin-line properties. Three bovine strains of group B streptococci produced very similar inhibitory activity. A greater variety of bacteriocin-like substances was detected in the group C streptococcus strains. Two of the S. zooepidemicus strains were each found to Produce more than one inhibitory substance.

An investigation into the incidence of hydatid disease was carried out in the Hebridean islands of Lewis and Skye. The results showed that 20% of the sheep were infected and 10% of the dogs harboured Echinococcus granulosus. Sporadic human cases continue to occur but using serological tests we were unable to show evidence of subclinical infection in the population sampled.

The majority of Shigella flexneri strains isolated in England and Wales are from infections contracted abroad. Most of these strains are drug-resistant, over 75% being resistant to streptomycin and sulphonamides, sulphonamides alone or streptomycin, sulphonamides and tetracyclines. A selection of resistant strains was tested for resistance transfer and the plasmids identified were characterized by compatibility grouping.

Streptomycin and sulphonamide resistance was usually determined by a non-autotransferring plasmid which may be mobilized by standard transfer factors, or by the plasmid which conferred tetracycline resistance where this was present. The remaining resistant strains were predominantly resistant to four or more drugs. These strains carried autotransferring plasmids of a variety of compatibility groups, of which groups B, I1 and FII were the most common.

A microagglutination method for determining the agglutinating and ‘blocking’ antibodies to Brucella abortus is described. A collection of sera from healthy blood donors in two rural areas of New Zealand were tested by the microagglutination methods and the standard methods in tube. The results are compared and show that where discrepancies occur, these are due to the microagglutination methods being more sensitive. It is concluded that these are suitable methods for screening populations.

When a 1:5 mixture of trimethoprim (TMP) and sulphadiazine was fed to pigs intra-nasally infected with Bordetella bronchiseptica, 10 mg/kg/day was shown to be highly effective in suppressing the organism. This dose level had little effect on numbers of TMP-resistant coliforms in faeces, but oral doses of 30 mg/kg/day eventually selected a resistant population. It is suggested that the proliferation of resistant coliforms would be minimized by administration of the lowest oral dose rates of antibacterial drugs compatible with efficacy.

During the ten-year period 1971–80 isolates of meningococci from 85 cases of meningococcal disease (MD) in South Australia, from 66 children, 6 adolescents and 13 adults, were examined. These comprised 69 cases of meningitis and 16 cases of bacteraemia without meningitis. Thirty-three (39%) of all cases of MD occurred in children less than 1 year of age, the median age was 19 months. Serogroup B accounted for 61 (72%) cases of MD, group A seven (8%), group C seven (8%), group W135 five (6%), group Y three (4%) and group X one (1%); in addition there was a single case of Neisseria lactamica infection.

The annual prevalence of MD in South Australia for the period was 11 cases per 100000 for children under the age of 2 years and 0·7 cases per 100000 overall. The prevalence was highest in winter (45% cases) and spring (26%) and lowest in summer (13%). The overall mortality rate was 8%. Four of the 21 infants under the age of 6 months died (mortality rate 19 %) whereas none of the 32 children aged from 6 months to 14 years died (P = 0·02). Amongst the survivors, three children had deafness, which was bilateral and severe in two.

Trimethoprim resistance was plasmid-encoded in all trimethoprim-resistant Salmonella typhimurium and in the majority of trimethoprim-resistant salmonellas of other serotypes isolated since 1970 from humans and food animals in Britain. In S. typhimurium, non-autotransferring plasmids of compatibility group 3 and autotransferring plasmids of group H2 predominated. The predominance of these plasmid types has resulted from the spread of clones of trimethoprim-resistant strains of phage types 18,170 and 204c. In other salmonellas, a variety of plasmid compatibility groups have been identified. Almost all plasmids which conferred resistance to trimethoprim also coded for sulphonamide resistance.

A seroepidemiological survey for toxocaral infection was performed using samples from children and adult women in the Yamaguchi area of Western Japan, An enzyme-linked immunosorbent assay using excretory–secretory antigen was applied to these sera. Of samples tested, 3·1% from children and 3·7% from women were positive. It was found that regression analysis of positive rates by age between 20 and 70 or more years was significant in the positive direction. The positive rates from urban, rural and fishing areas were 5·7, 3·9 and 1·7% respectively. Also, the rates from northern, western and eastern parts in the research area were 5·7, 4·7 and 0·5% respectively. These findings suggested that environmental factors are important for toxocaral infection. Further, the rate for 108 samples who answered that they have owned dogs was 6·2% compared to 2·9% of 422 respondents who denied an experience of owning dogs. This fact suggested thatattention should be paid to dog breeding for prevention and control of toxocaral infection in man.

Sera were collected from female cattle in 118 commercial herds being subjected to a programme to eradicate brucellosis by test and slaughter, in an area in which vaccination of heifer calves with Brucella abortus strain 19 was compulsory. Of 4583 sera positive by the Rose Bengal plate test, the brucellosis radioimmunoassay was positive for 1524, the complement fixation test for 1363 and the indirect haemolysis test for 1141. These figures, and supporting evidence from the eradication programme, suggest that the radioimmunoassay may be a useful supplementary test in problem herds.

A collection of more than 300 strains belonging to either Lancefield group C or group G was made. The cultures had been isolated either sporadically from patients with serious disease or as apparent clusters from various nosocomial outbreaks. T-protein antigens were sought. So far, nine distinct serotypes have been found among the group G streptococci and seven serotypes amongst the Streptococcus equisimilis (group C) strains. Of the sixteen serotypes, four were the original T-types 7, 16, 20 and 21 described by Griffith (1934). Because of the similarities of representatives of the two groups to Lancefield group A streptococci (Griffith, 1934; Maxted & Potter, 1967) a few strains not unexpectedly carried T antigens usually seen in group A streptococci. Using this scheme it has been possible to serotype 76% of S. equisimilis strains of human origin and 82% of group G streptococci from human clinical material. A small collection of group C and group G streptococci of animal origin could not be serotyped with the experimental T-antisera.

Infection of guinea-pigs by intranasal (i.n.) instillation of 109 viable organisms of two newly isolated strains of Legionella pneumophila (74/81, serogroup 1; 166/81, serogroup 3) did not induce disease, but 104 organisms administered as a small particle aerosol (< 5 μm diameter) produced a fatal widespread bronchopneumonia within 3 days. Milder illness and less extensive bronchopneumonia were also produced in rhesus monkeys and marmosets by one of these two strains (74/81). Mice were resistant to induction of disease by aerosols of both these two strains, though organisms did persist in the lungs for at least 4 days. Both of these L. pneumophila strains were pathogenic for guinea-pigs by aerosol infection over a wide range of doses but the serogroup 1 type strain (NCTC 11192) was not. There was no mortality after infection of guinea-pigs by intranasal instillation of any of these strains but all proved to be fatal after intraperitoneal (i.p.) injection of large doses. Guinea-pigs, rhesus monkeys and marmosets exposed to aerosol infection with L. pneumophila provide relevant models for studying the pathogenesis of Legionnaires' disease.

The pattern of phage types of 2553 strains of Salmonella typhi isolated over the 10-year period 1970–9 was studied. During the period 29 different phage types were encountered, not including the categories of ‘untypable strains’, ‘degraded Vi-strains’ and Vi negative strains. For the period as a whole, the commonest phage types encountered were A (20·9%), E1 (14·8%), D1 (10·3%), degraded Vi positive strains (10·3%), untypable Vi strains (7·3%), C4 (7·1%), D2 (4·4%), E2 (3·9%) and type 25 (2·6%). There were phage types which appeared in the early years of the period and then disappeared (types B2, D9 and D1-N). Others only made their appearance in recent years (K1 and 53). Notable differences were also seen in the predilection of some phage types for certain geographical areas.

The epidemiology of enterotoxigenic Escherichia coli (ETEC) was studied in children without diarrhoea in two remote Aboriginal communities in tropical north-western Australia. Serial surveys of the same individuals during different seasons showed that isolations were much more frequent in the wet monsoonal summer than in the dry winter. All E. coli were isolated from symptomless children aged 5 years or less; in addition, clearance of ETEC carriage without treatment was observed in all individuals within 3 months of isolation. Of the 58 ETEC strains isolated, 40 had either an H32 or an O126 antigen. Five O antigens which have never been associated with ETEC (O2, O41, O71, O77 and O157) were found. A recently proposed system to detect ETEC, using groups of polyvalent antisera, would have detected only 3 out of these 58 ETEC strains.

One hundred and nineteen volunteers were divided into five groups, and each volunteer inoculated subcutaneously with an aqueous subunit B/Hong Kong/73 vaccine containing 40, 20, 10, or 5 μg of HA or saline alone in a 0·5 ml volume. The incidence of reactions was recorded 24 h after inoculation. One month following immunization the serum HI antibody to B/Hong Kong/73 virus was measured; each volunteer was inoculated intranasally with live, attenuated influenza B (RB77) virus; and the incidence of infection by the challenge virus was determined by HI antibody response.

The results showed that the incidence of reactions to all doses of vaccine were relatively low, the severity mild, and the duration short. However, the incidence of reactions was highest for those given 40 μg HA and least for those given 5 μg HA. The serum HI antibody responses to vaccine showed a dose-response relationship. For volunteers given 40 μg HA, 22 (96%) showed a fourfold rise in antibody titre and all volunteers had antibody titres of > 40 following immunization: for volunteers given 5 μg HA the g.m.t. increased from 16·6 to 86·1; and for those given 10 and 20 μg HA the response was intermediate. Following challenge, the lowest incidence of infection was seen in volunteers given the highest dose of vaccine. However, all doses of vaccine induced some protection against challenge virus infection, and the incidence of infection was directly related to the serum antibody titre at the time of challenge. The 50% protection titre of serum HI antibody was estimated as 15 to 20.

Human rotaviruses from the states of Rio de Janeiro, São Paulo and Pará of Brazil were analysed by RNA electrophoresis. At least some bands characteristic of rotavirus double-stranded RNA were detected in 138 (86·8%) of 159 faecal samples in which the presence of rotavirus had been demonstrated by enzyme immunoassay. Of the RNA-positi ve samples, 18 (13·0%) were classified as subgroup 1, 94 (68·1%) as subgroup 2, and 26 (18·8%) could not be classified due to absence of visible bands 10 and 11. Subgroup 2 was more frequent in the three states. All strains of subgroup 1 detected in Rio de Janeiro were associated with a single short-lived school outbreak. All strains of subgroup 1 resembled each other in electrophoretie pattern, irrespective of geographical origin, although minor differences could be detected by co-electrophoresis. Subgroup 2, on the other hand, showed a great degree of electrophoretic heterogeneity and could be divided into several sub-categories.

A detailed investigation into the effect of modifying the incubation temperature of the complement-fixation (CF) test is described. For varicella-zoster virus cytomegalovirus and rubella virus, increasing the incubation temperature progressively increased the sensitivity of the CF test to reach a maximum at 15°C, at which temperature the geometric mean titre of seropositive samples was significantly greater than that found at 4°C. For these three viruses, each serum shown to contain IgG antibodies by ultrasensitive radioimmunoassay procedures was detected by CF following incubation at 15°C. No false-positive reactions occurred at 15°C, but it was our impression that anticomplementary activity was enhanced at this temperature. Significant increases in antibody titre at 15°C were also seen when measles virus, respiratory syncytial virus, adenovirus and Mycoplasma pneumoniae were employed as CF antigens. The results demonstrate that the CF test should be performed at 15°C if optimum sensitivity is to be achieved. The ability of the test to detect significant rises in antibody titre was not impaired at the higher incubation temperature.

Hybridomas secreting monoclonal antibodies to HBsAg and HBcAg were prepared from immunized mice. An antibody capture radioimmunoassay was used to detect and select appropriate hybrids for propagation and cloning. The advantages of this assay were discussed. The resulting monoclonal antibodies were compared with conventional polyclonal antisera for the detection of virus antigens in liver tissue and found to give excellent results.