We have tried to detect prenatal infection in 34 infants whose mothers were re-infected with rubella virus during pregnancy and in six infants whose mothers had primary subclinical rubella during pregnancy. Two methods of assessment were used: first, serum obtained soon after birth was tested for IgM antibody; secondly, serum obtained after the age of 8 months was tested for specific IgG.

The 34 women with re-infections had increases in IgG antibody titre but no IgM response. No evidence of prenatal infection was found in 33 of their 34 infants. One infant was found to have IgG antibody at the age of 11 months. This infant was IgM-negative at birth and had a rubelliform rash at the age of 5½ months; it therefore probably contracted post- rather than pre-natal infection. Fetal infection from maternal re-infection during pregnancy is probably rare.

The six women with primary subclinical rubella produced both IgG and IgM classes of antibody. Three of their six infants showed serological evidence of intrauterine infection. One, infected when its mother was 8 weeks pregnant, had clinical evidence of congenital rubella. Primary subclinical rubella during pregnancy therefore carries a significant risk of fetal infection.

Because of the difference in outcome, great care should be taken to distinguish between primary infection and re-infection when investigating symptomless increases in antibody titre after contact with rubella during pregnancy.

A large outbreak of campylobacter enteritis associated with the consumption of free school milk is described. The outbreak had an abrupt onset, and lasted for about 3 weeks; it involved mainly school children in the 2–4 and 5–7 year old age groups. During this period it was established from epidemiological and microbiological data that some 2500 children were infected. The source of the epidemic was almost certainly contaminated milk, although bacteriological proof could not be obtained. Biotyping of isolates was of considerable epidemiological value and showed the involvement of two distinct strains, one of which was dominant. Epidemiological evidence of limited person to person transmission of the infection was obtained; febrile convulsions as a prodromal sign of the illness was recognized for the first time. Strains of Campylobacter jejuni, and samples of patients' serum collected during this outbreak have enabled subsequent studies to be initiated on the serotyping of the responsible organism, on the serological response of patients infected with the organism, and on experimental infection of the bovine udder which demonstrated its potential as a source of C. jejuni in raw milk. A careful search of the literature suggests that this is the largest documented outbreak of campylobacter enteritis.

Two outbreaks of campylobacter enteritis in residential student populations are described. In the first outbreak, 34 of 240 students in one hall of residence became ill over the course of 4 or 5 days. A single serotype of C. jejuni was isolated from samples of faeces. Sera collected demonstrated that the students had little pre-existing antibody and antibody responses were demonstrated in those who were infected. About 30% of students with serological evidence for infection with C. jejuni did not have gastro-intestinal symptoms.

In the second outbreak, 77 of 300 agricultural students developed symptoms over a period of 3 weeks. Unpasteurized milk was the source of infection. Two serotypes of C. jejuni were isolated from faeces. Antibody responses were detected to both these serotypes and to another serotype, suggesting the presence of at least 3 serotypes in the milk. Bactericidal antibody consistent with recent infection was found in all students with symptoms and in 63% of students in the absence of symptoms, indicating the possible development of immunity. The high prevalence of antibody in these students was correlated with the habitual consumption of unpasteurized milk.

Laboratory and field trials were conducted to determine the efficacy of the anticoagulant rodenticide bromadiolone against the house mouse (Mus musculus). In laboratory feeding tests, family groups of warfarin-resistant mice maintained in pens and conditioned to feeding on plain foods were offered pinhead oatmeal bait containing bromadiolone at 0·005%. Overall mortality in replicated 21-day poison treatments was 55/58 or 94·8%. Six field trials were carried out, using the same poison bait, against mice infesting farm buildings. Treatment success, estimated from the results of census baitings conducted before and after treatment, ranged between 60·4% and 100%, mean 92·4%. In equivalent field trials using difenacoum, another newly developed anticoagulant rodenticide, the control achieved ranged between 70·2% and 100%, mean 96·0%.

Five field trials, three involving bromadiolone and two difenacoum, were not completely successful and the surviving mice were removed for laboratory examination. In 21-day toxicity tests, each animal was fed the poison bait offered to it earlier in the field. Bromadiolone and difenacoum gave kills of 12/21 (57·1%) and 9/11 (81·8%) respectively. The possible emergence of mouse populations resistant to these anticoagulants is considered.

Brodifacoum was evaluated in the laboratory against the two gerbils, Tatera indica and Meriones hurrianae and the house rat, Rattus rattus. The acute oral LD50 for these rodents was found to be 0·10 mg/kg, 0·083 mg/kg and 0·77 mg/kg respectively. Feeding tests with 0·002% and 0·005% brodifacoum produced a 100% mortality after a 3-day feeding period in the gerbils and after a 4-day period in R. rattus. The anticoagulant is toxic at both the concentrations to all three species but is less palatable in comparison to plain baits. Results of this laboratory evaluation indicates that 0·002% brodifacoum-treated bait can be effectively used against T. indica, M. hurrianae and R. rattus.

Antigenic variants of A/Texas/77 (H3N2) virus were selected in vitro using monoclonal antibody to virus haemagglutinin (HA). The antigenic variants and parental A/Texas/77 viruses were used to evaluate the frequency of anti-HA antibodies in the sera of children and adults using single-radial-haemolysis (SRH) tests. Twenty to 41 % of selected sera from adults, which contained antibody to the parental A/Texas/77 virus, failed to react with the different antigenic mutant viruses. A higher proportion of sera from children (37–58%) failed to react with the antigenic variants. Certain human sera and particularly those of children would appear to possess a more limited antibody repertoire to influenza HA, potentially allowing new antigenic variants to escape neutralization and spread in the community.

A five year collaborative study of influenza in volunteer families from 1973–78 covered a period in which there were outbreaks every year but no major epidemics of influenza. Volunteers over the age of 15 years were bled before and after each of the five winters, and virus isolation was attempted from as many as possible when they reported episodes of illness. Children under 15 in the volunteer families were also swabbed when they were ill. Although most families experienced one or more attacks by influenza viruses, there was little transmission within families.

A group of 269 pupils of the Harbour and Transport Training Institute in Rotterdam (group A), aged 13–20 years, and of 109 patients of the Dr Mr Willem van den Bergh Foundation at Noordwijk (group B), aged 11–21 years, were immunized with a whole virus vaccine containing 10, 20, or 40 μg HA of A/USSR/92/77 (H1N1) influenza virus. A booster vaccination was administered 6 weeks later with 20 μg HA of the same virus. Many of the participants had been immunized during the two preceding years with a whole virus vaccine containing A/New Jersey/8/76 (H1N1) (A/NJ/76) virus. The side-effects, mostly of a moderate nature, increased with the dose of virus in the vaccine. In group A side effects were least frequent in the vaccinees who had never received A/NJ/76 vaccine. A single dose of A/USSR/77 vaccine did not produce satisfactory levels of homologous antibodies. After booster immunization with 20 μg HA of A/USSR/77 virus participants showed a higher homologous antibody response in all vaccine-dose groups if they had not been immunized with A/NJ/76 virus in previous years. After primary and especially after booster immunization with A/USSR/77 virus, a very high response against A/NJ/76 virus and adequate levels of A/NJ/76 antibody were found in participants who had been immunized previously with A/NJ/76 virus. Those who had not been immunized with this virus previously showed no or a very low antibody response to A/NJ/76 virus.

The technique of radial haemolysis (SRH) was used to assess the response to infection with different strains of influenza B virus, to determine the persistence of antibody following such infection and to examine sera from boys entering school at age 11 years. The technique detected 95 % of infections and in primary infection the antibody response was mainly to the infecting strain. Re-infections resulted in a broad response, both to the homotypic strain and to strains more distantly related. Antibody to the homotypic strain persisted for at least 3 years but in some individuals the reaction with heterotypic strains tended to become weaker – resulting in zones of incomplete lysis – or was lost. Examination of the sera collected on entry to the school showed that about 60 % of the boys bled before B/Hong Kong became widespread in the United Kingdom had antibody to strains representative of those isolated in the 1960s and few boys had antibody to B/Hong Kong. After 1974 antibody to B/Hong Kong and later strains became more common while antibody to earlier strains was less frequently detected. The significance of the results as an estimate of past experience is discussed.

Six hundred and eighty three samples of chicken giblets were examined for salmonellas. Three hundred and forty nine of these were neck and crop specimens and 334 were combined liver and heart samples. Two hundred and ten, in all, contained salmonellas.

The technique of examination included pre-enrichment in buffered peptone water at 37 °C for 18 h and subculture to three enrichment media: Muller-Kauffmann tetrathionate, selenite F and Rappaport's magnesium chloride malachite green broth. Inocula from buffered peptone water to 10 ml of tetrathionate and selenite were 1 ml in each case. The inoculum from the pre-enrichment medium to 10 ml of Rappaport was 0·005 ml. Tetrathionate and selenite were incubated at 43 °C for 48 h. Rappaport's medium was incubated at 37 °C for 48 h. Subcultures from all three enrichment broths were made at 24 h and 48 h to brilliant green MacConkey agar. Selective agars were incubated at 37 °C for 24 h.

The most successful technique for salmonella isolation used Rappaport's medium, which was significantly more efficient than either tetrathionate or selenite. This finding reinforces results obtained using sewage polluted natural water as test material and it is suggested that routine examination of environment samples for salmonellas could be based on Rappaport's medium alone.

If S. typhi, S. dublin or subgenus III salmonellas were likely to be present in the sample, the technique described here would require modification.

The distribution of salmonellas along the gastrointestinal tract and in associated lymph nodes were studied in 100 sheep and 100 cattle at slaughter. Animals were chosen from those slaughtered on the first day of the week, since this meant that they were likely to have been held at the abattoir for several days and thus to be at high risk of salmonella infection. The contents of the rumen, abomasum, ileum, caecum and rectum were sampled, together with the lymph nodes draining each of these sites.

Of the cattle, 77 were carrying salmonellas, including 61 with infected lymph nodes, whereas only 43 sheep were infected, 14 of them with infections in the nodes. The lower prevalence in sheep than in cattle might be explained by a shorter time between leaving the property and slaughter. In both species, within the gastrointestinal tract salmonellas were most frequently found in the caecum and rectum and least frequently in the abomasum. In cattle salmonellas were frequently present, usually in large numbers, in the lymph nodes draining the ileum, caecum and colon, but rarely in the ruminal and abomasal nodes; however this difference was not apparent in sheep. Over 70 % of infected animals yielded more than one serotype, the maximum number isolated from any one animal being ten.

A total of 19200 children, all contacts or relatives of known leprosy patients, and all free of visible leprosy lesions, were included in a controlled trial of BCG vaccination against leprosy in Uganda between 1960 and 1964. They were followed for an average of 8 years, during which time 261 developed early leprosy lesions. A less comprehensive follow-up was carried out for a further 5 years, when 8 more cases of leprosy were identified.

In the main intake, between 1960 and 1962, 16150 tuberculin-negative or weakly tuberculin-positive (Heaf Grades O-II) children were allocated by an effectively random process to either a BCG-vaccinated or an unvaccinated control group. Both groups were seen and examined in an identical fashion for leprosy at approximately 2-year intervals, and precautions were taken to ensure unbiased assessment of new cases of leprosy. After 8 years, 41 cases of leprosy had been identified in the BCG-vaccinated group, and 201 in the control group, a percentage reduction in the BCG-vaccinated group compared with the control group of 80%. The percentage reduction was similar for those initially tuberculin-negative, and for those initially weakly positive, and did not depend upon the age at vaccination. It was also similar for both sexes, for contacts of lepromatous and contacts of non-lepromatous leprosy, for children having contact with one or more than one patient, and for differing grades of physical contact and genetic relationship with a patient. The protective effect of BCG vaccination continued over the 8-year period, although it may have fallen off slightly at the end.

In a group of 1074 strongly tuberculin-positive (Heaf Grades III-IV) children followed in parallel with the other two groups a total of 16 cases of leprosy were identified. When adjusted for age, this incidence is 58% lower than that in the unvaccinated control children who were initially tuberculin-negative, indicating a protective effect against leprosy of naturally-acquired strong tuberculin sensitivity.

Between 1970 and 1975, one new case of leprosy was identified in a child who had initially been strongly tuberculin-positive and had therefore not been vaccinated, one in a BCG-vaccinated child, and 6 in control children. Although the follow-up in this period was less comprehensive than that in the main part of the trial, the ascertainment of cases was unlikely to have been biased towards either vaccinated or control children. These results indicate a continuing protective effect of BCG up to 12–13 years after vaccination.

Radioimmunoassay (RIA) for rubella-specific IgM antibodies was compared with haemagglutination-inhibition (HI) in conjunction with gel filtration for the diagnosis of rubella infection in pregnant women during a 1-year period. In total 476 women were investigated of whom 221 were tested for rubella IgM. Both techniques gave positive results with 64 sera, and RIA alone with one additional serum.

Difficulties associated with the removal of non-specific HI activity were encountered with four sera all of which were negative by RIA.

RIA was found to have practical advantages over the gel filtration method but is at present technically more difficult to perform.

A total of 321 Salmonella typhimurium strains of bovine origin obtained in northern Japan during the period 1970–1979 were tested for drug resistance and detection of conjugative R plasmids. Three hundred and eighteen (99·1 %) of these strains were resistant to one or more drugs. The isolation frequency of multiply drug-resistant strains tended to increase year by year. Two hundred and thirty-seven (74·5%) of these resistant strains carried conjugative R plasmids. A total of 308 R plasmids including 174 (56·5 %) thermosensitive (ts) R plasmids were derived from the 237 drug-resistant strains, indicating that 71 (30·0%) strains have two different conjugative R plasmids in a single host cell. Of the 308 R plasmids examined for fertility inhibition (fi), 167 ts and 131 non-ts R plasmids were fi−. Of the 60 ts R plasmids examined for incompatibility, 50 were classified into H1 group and 10 into H2 group. Of the 52 non-ts R plasmids examined, 35 were classified into the Iα group and the remaining plasmids were untypable in our tests. Mercury resistance marker was found in about 20% of H1 R plasmids coding for multiresistance, and all of H2 R plasmids coded for resistance to tellurite. The clonal distribution of an S. typhimurium strain which carried an H1 R plasmid coding for resistance to six drugs and mercury was recognized in 1978 and 1979.

Corynebacterium haemolyticum infections are described for the first time in Sri Lanka. In a period of 2 years from 1978–80 C. haemolyticum was isolated from the pharynx of 9 patients with tonsillitis and from local septic lesions in 7 other patients. Association with other pathogens was common. No patients had a rash. The properties of the isolates are described.

During a period when 245 patients were infected by or harboured gentamicinresistant enterobacteria, random sampling showed hand carriage in 33% of affected patients but in only 5 % of attendant staff. Only klebsiellae were isolated from the latter. Recovery was commoner from the hands of bed-ridden patients or faecal carriers and significantly more frequent for klebsiellae (37 %) and enterobacter (33 %) than citrobacter (5·6 %) and E. coli (5·0 %). Similarly, survival on forearms of volunteers was much longer for klebsiellae and enterobacter than for citrobacter or E. coli (means respectively were 70, 45, 10 and 13 min), and on dry surfaces (means respectively were 28, 26, 3 and 7h). Klebsiellae were isolated from 17 of the 56 dry environmental surfaces sampled. The presence of plasmid resistance determinants had no effect on survival times, either on the skin or following drying onto formica surfaces. On dry surfaces 9·5% of E. coli but only 1·3% of klebsiellae lost resistance to gentamiein. These findings accord well with recent experience in which gentamicin-resistant klebsiellae have been involved to a much greater extent than other resistant enterobacteria in hospital infection.

The Microbact-24E and the Microbact-12E systems are two new miniaturized identification systems for the identification of organisms belonging to the family Enterobacteriaceae. These two systems were compared to the API-20E system for the identification of 352 fresh clinical isolates of Enterobacteriaceae. All three systems were easy to use and came complete with computerized profile registers to assist with final identification of the isolates. The Microbact-24E identified 98 %, the API-20E and MB-12E identifying 94·3% and 88·6% respectively. Where different identifications were obtained with the Microbact-24E and API-20E conventional biochemical tests, motility and serology were performed. The Microbact-24E system proved to be a very accurate and convenient means of identifying members of the family Enterobacteriaceae.

Bacteroides spp. were isolated from the faeces of neonates and identified by rapid modifications of established conventional methods. Gram-negative anaerobic bacilli were recovered from 12 out of 16 neonates and a heavy growth of Bacteroides spp. was obtained from all 12 specimens. Twelve representative isolates from each subject were selected for identification; 141 of the 144 Bacteroides isolates belonged to the B. fragilis group and three to the B. melaninogenicus/oralis group. Eight species were represented within the B. fragilis group. B. vulgatus (c. 46%) and B. thetaiotaomicron (c. 30 %) were the predominant species. B. fragilis, the type-species of the group, formed only a small proportion of neonatal faecal flora. The proportional representation of individual species were similar to that found in adults but B. asaccharolyticus was not represented.

Echovirus type 11 (echo 11) has been isolated at the virus laboratory of Fairfield Hospital, Melbourne, Australia, in 20 of the 28 years since the laboratory was established. During this time two major epidemics have occurred; the first, in 1971–2 involved 90 patients with aseptic meningitis or respiratory illness. The second began in June 1979 and lasted for 11 months, during which echo 11 was isolated from 174 patients admitted to Fairfield Hospital, other Victorian and Tasmanian hospitals and a children's reception centre. The patients' illnesses included viral meningitis (66%), fever (10%), respiratory infections (7%) and gastroenteritis (2%). One baby died.

Echo 11 was recovered from nasopharyngeal swabs or aspirates, cerebrospinal fluid and faecal specimens and was isolated most frequently in the Borrie cell line. Isolates were readily identified by immune electron microscopy and/or neutralization tests.

Steatorrhoea was a significant feature in an outbreak of rotavirus gastroenteritis which affected adults and infants in hospital. Fat globules or fatty acid crystals were obvious by light microscopy (LM) in faeces from 14 of 25 patients examined. Ten of the fatty stools and two of the remainder were very pale. By electron microscopy (EM) a rotavirus was seen in 11 of the 14 fatty faeces and in only two of 11 specimens without visible fat.

In a further study of pale or fatty faeces 20 such specimens sent for laboratory examination from patients not involved in the hospital outbreak were compared microbiologically with a similar number which were neither pale nor fatty. Viruses were found by EM in 11 (55%) of the pale or fatty stools; eight rotaviruses, two astroviruses and an uncultivable adenovirus were seen; one further patient had acute jaundice. In contrast, no viruses were seen by EM in the twenty specimens which were normally pigmented and without evident fat.

Steatorrhoea was significantly associated with rotavirus infection of the alimentary tract which usually presented as a fatty enteritis. We conclude that rotaviruses certainly, and other viruses possibly, can impede both the digestion of fat and the pigmentation of the faeces. Inspection and LM of faeces are easy. In acute enteritis a fatty or pale stool is an indication for virological examination.