The presence of genetic resistance to myxomatosis in a sample of wild rabbits from one area in England was reported in 1977. Rabbits from three other areas in Great Britain have been tested subsequently, and all cases showed similar resistance to a moderately virulent strain of myxoma virus. Rabbits from one area also showed a significant degree of resistance to a fully virulent strain of virus.

It is concluded that genetic resistance to myxomatosis is widespread in wild rabbit populations in Britain. The implications of the results are discussed in relation to the co-evolution of the disease and its host.

Three hundred volunteers were divided into two age groups, 14–30 years and 31–60 years. Each participant was immunized intramuscularly with a subunit, whole virus or adsorbed whole virus vaccine, containing A/Bangkok/I/79 (H3N2), A/Brazil/ 11/78 (H1N1)and B/Singapore/222/79 influenza virus. Serum haemagglutination-inhibition (HI) antibody response, protection, and reactogenicity were studied after one and two doses of the vaccines. Primary immunization induced much higher percentages of HI antibody titres ≥ 100 against all three vaccine viruses and much higher geometric mean titres (GMT) in volunteers with pre-immunization titres ≥ 18 as compared to those with pre-immunization titres < 18. Secondary immunization did not result in an increase of GMTs or antibody titres ≥ 100 in volunteers with pre-immunization titres < 18. On the whole, the response to the subunit vaccine was similar to that to the other two vaccines. To influenza B/Singapore/222/79 virus the response was lowest after administration of the whole virus vaccine in the age group 31–60 years. Over 50% of the HI titres ≥ 100 found after immunization in the different vaccine and age groups were still present after one year. Serologically established infections during the winter months following immunization amounted to 15% in the subunit vaccine group, 6% in the whole virus vaccine group, and 10% in the adsorbed whole virus vaccine group. Local and systemic reactions to all three vaccines were mild in nature. Local reactions after primary immunization were much less frequent following administration of the subunit vaccine as compared to the other two vaccines, especially in the younger age group. In comparison to primary immunization, after booster immunization the incidence of local reactions was higher for the subunit vaccine and lower for the adsorbed whole virus vaccine. In the age group 14–30 years the incidence of local reactions after primary as well as booster immunization was much greater in females than in males, especially when the adsorbed whole virus vaccine was used.

Rubella vaccination histories were taken from 333 young women working in the head office of a retail organization: 29% said they had had vaccine and 47% said they had not. The remainder did not know. Forty-six per cent of those ≤ 25 years old (who should have been offered vaccine at school), and 6% of those > 25 years old, said they had been vaccinated. When screened for immunity to rubella by radial haemolysis (RH) 3% had a low level of antibody (< 15 i.u./ml) and 11% had no antibody. After immunization with Cendevax the specific rubella IgM response was measured by an IgM antibody capture radioimmunassay (MACRIA). It was only detectable in the group without RH antibody, and was present in 26/31 of them. The Ig M response to Cendevax was strongest in specimens taken 20–39 days after immunization, but in 10 out of 11 cases tested was still present at around 71 days. The specific Ig M responses to Cendevax were very similar to those in women given Almevax in an earlier study, when measured in parallel tests.

Taking both vaccines together, specific Ig M was present in 35 out of 36 vaccinees without pre-existing antibody tested between 40 and 77 days post-immunization. Detection of specific IgM by MACRIA would therefore be an effective means of determining susceptibility retrospectively in rubella vaccinees found to be pregnant.

The duration of immunity following a single administration of rinderpest cell culture vaccine, of 90 or more monolayer passages, was studied in E. African zebu (Boran) and grade (cross-bred European) cattle. All animals were kept for periods of 6–11 years in rinderpest-free environments; groups of them (in all 23 Borans and 10 grades) were then challenged by parenteral or intranasal inoculation of virulent virus or by contact exposure to reacting cattle. Nasal excretion of virus was studied daily over the 10-to 14-day period following challenge, and simultaneous attempts were made to detect viraemia. The neutralizing antibody response was followed at 6-month intervals over the whole post-vaccination period and then daily for 10 days and at longer intervals to 3 weeks after challenge.

All 33 animals which were exposed by various routes failed to react clinically and a rinderpest viraemia was never detected. No transmission of virus from the vaccinates to susceptible in-contact controls occurred within 14 or more days, from the 20 animals which could be so tested. Clearcut serological responses to challenge were seen in six cattle (four Borans and two grades) which were challenged after 7 years or more; these reactions were all delayed to the 9th or 10th days, i.e. they were not typically ‘anamnestic’.

These results are discussed in relation to mass vaccination campaigns for the control of rinderpest and from the comparative viewpoint of measles vaccination in man.

Pregnancies were identified in which maternal IgG antibodies against rubella virus were not detectable by single radial haemolysis. Twenty paired maternal/cord sera were then tested for haemagglutination-inhibiting (HI) activity against rubella virus without kaolin pretreatment of the sera. In the absence of specific antibody, the HI activity observed could thus be ascribed to the effect of non-specific inhibitors. The HI activity in maternal sera was significantly (P < 0·001) higher than that in cord sera. The 20 pairs of sera were similarly tested against a bunyavirus, an alphavirus and a flavivirus, both with and without kaolin pretreatment. The results showed non-specific inhibitors were found to higher titre in maternal sera, with the difference being statistically significant (P < 0·001) for each of the three viruses.

A general practice population of around 3900, under continuous clinical and laboratory surveillance, experienced 20 outbreaks of influenza between March 1960 and March 1976. Four epidemics were caused by subtype H2N2 type A viruses, seven by subtype H3N2 type A viruses and nine outbreaks by type B viruses. The age of every person proved virologically to have influenza is related to the age structure of the community and to the phase of the epidemic in which the virus-positive specimens were collected. Children 0–15 years old suffered a higher incidence rate than adults 16–90±. Pre-school children 0–4 suffered the highest rate of infection by viruses of both influenza A subtypes, whereas older schoolchildren 10–15 suffered the highest rate of type B infections. Despite these high incidence rates neither pre-school nor schoolchildren appear to have been the major disseminators of any of these influenza viruses in the community.

Adults of all ages suffered a high rate of infection even into extreme old age, and the indiscriminate age distribution among adults was sustained in the successive epidemics. Such age-patterns are not those caused by a highly infectious immunizing virus surviving by means of direct transmissions from the sick, whose prompt development of the disease continues endless chains of transmissions. An alternative epidemic mechanism – whereby the virus does not spread from the sick but becomes latent in them, reactivating seasonally so that they later infect their companions – would produce age patterns similar to those recorded here for influenza patients. The suggested mechanism is illustrated by a simple conceptual model and the influenzal age patterns are discussed in relation to the recycling of influenza A subtypes.

In 1980, an outbreak of a mild illness involving twenty pupils and four adults in a boys' boarding school was identified serologically as psittacosis. Intensive epidemiological investigations did not uncover the source. It is suggested either that sources of chlamydia other than avian exist, which may produce a milder illness than the avian type, or that human-to-human spread of a mild form of chlamydiosis occurs.

A model for contact transfer of micro-organisms by hand has been extended to include representatives of bacterial species responsible for a majority of hospitalacquired infections. The ability of the organisms to transfer from contaminated fabrics to hands and from hands to sterile fabrics was measured, as was their ability to survive on the skin of the hands. There were differences between the species. Staphylococcus saprophyticus transferred well to the hand but not as well from hand to fabric as the other species; it survived well on skin. Pseudomonas aeruginosa, Klebsiella aerogenes and Serratia marcescens transferred moderately well overall and also survived on the skin. These results were in contrast to those obtained with a strain of Escherichia coli and one of Streptococcus pyogenes.

The contact transfer model was used to investigate the use of small volumes of alcohol in preventing transfer via the hands. An alcohol handrub of either 0·3 ml 80% ethanol or 0·3 ml 70% isopropanol gave reductions in transfer slightly less than that of a soap and water wash. Raising the volume, and consequently the contact time, to 0·5 ml 70% isopropanol gave a 14000-fold reduction in transfer, statistically indistinguishable from that of a thorough soap and water wash (9800-fold reduction).

Campylobacters were sought in swabs taken from work surfaces, sinks and floors of four kitchens–i.e. hospital, university, cook-freeze and commercial, processing frozen or fresh chickens. Each kitchen was visited on four occasions. In the large commercial kitchen environmental contamination was found on each visit, whereas campylobacters were isolated on six of the twelve visits to the other kitchens. The hands of operatives were contaminated with campylobacters on only two of the 45 swabs taken during processing. Cleaning with detergent and hot water (or steam) and drying appears to be sufficient to remove the organism from the environment.

Evidence of carriage of campylobacters by the birds was obtained on all 16 visits. In the three kitchens where only frozen birds were used the organism was isolated from 30% and 9·8% of swabs taken from the internal and external surfaces respectively, while 41 % of giblets and 22·2% of thawed juices yielded campylobacters. The external surface of 30 (88%) of 34 fresh birds grew campylobacters.

Faecal samples from 110 horses, 115 pigs, 111 sheep and 123 cows were examined for the presence of Aeromonas hydrophila, which was also sought in the available drinking water.

The overall faecal rate was 11·8%, but significantly more bovine than other samples were found to be positive. There was significant association between the isolation of A. hydrophila from all animal faeces and its presence in drinking water, but this was not found when individual animal groups were analysed separately. An enrichment technique increased the total number of isolates by 77·1 %. Strains of differing origins could not be differentiated by biotyping, although fermentation of sorbitol was associated with bovine isolates. There was a strong positive correlation between positive reactions for V–P, gluconate oxidase and haemolysis of rabbit erythrocytes, tests which had previously been shown to correlate with production of enterotoxin and cytotoxin. Biotypes giving positive reactions for these tests were most frequently isolated from cows, sheep and untreated water, and less frequently from pigs and horses. Most strains of A. hydrophila were resistant to amoxycillin, carbenicillin and cephradine, and sensitive to gentamicin, chloramphenicol and neomycin.

Isolates from the intestinal Escherichia coli flora of 28 members of five families (including parents, children, and household pets) in Amherst, Massachusetts, and Rochester, New York, were characterized by the electrophoretic mobilities of 12 enzymes to estimate the extent of sharing of strains among associated and unassociated hosts. Among the 655 isolates examined, 60 different combinations of electromorphs (electrophoretic types or ETs), each representing a distinctive multilocus genotype, were identified, of which 85% were recovered from only a single individual. On average, 11 % of the ETs isolated from the same family were shared by two or more members; 4·9% of ETs were shared among members of unassociated families living in the same city; and only 2% were shared by families in different cities. All three ETs that were recovered from multiple hosts in the present study are widespread clones that have been isolated from many other host individuals in North America and Sweden.

Three variables were included in a study to determine their effect on the incidence of Salmonella typhimurium in broilers challenged at four days of age. Variables included the presence or absence of a feed additive, avoparcin; the use of new or used litter and the initiating dose of salmonella. Cloacal swabs were taken from approximately 600 chicks at weekly intervals for 45 days. At 104, 106 and 108 c.f.u./chick there was a direct association of challenge dose and the incidence of positive chicks for the first several weeks. Chicks raised on used litter showed an appreciable reduction in susceptibility to salmonella when compared to control animals on fresh litter. As the birds approached slaughter age, the influence of litter hygiene and challenge dose diminished under the conditions of this study. Avoparcin in the diet at 10 p.p.m. had no enhancing effect on salmonella shedding at any time during the 45-day sampling period. The implications of competitive exclusion are discussed.

The results of serotyping of 10953 salmonella isolates from humans over a 10-year period, 1973–82 at the Bacteriology Division, Institute for Medical Research, Malaysia are presented. A total of 104 serotypes from 22 ‘O’ groups were encountered; 95 isolates were considered untypable. The three most predominant serotypes, namely Salmonella typhi, S. typhimurium and S. weltevreden together accounted for 54·1% of all isolates whilst the 25 most frequent serotypes accounted for 93·6% of the total. Whilst the commoner serotypes occurred regularly throughout the study period, the rarer ones tended to appear only in one year, when they might be associated with an outbreak, and never again.

The pattern of serotypes, though quite similar to the one seen in neighbouring Singapore, is different from those experienced in other places such as Hong Kong, Jakarta, Bangladesh and Manchester.

Sera from healthy blood donors from different parts of New Zealand, collected between 1977 and 1980, were analysed by the microagglutination technique for antibodies against Brucella abortus. Populations from both urban and rural areas were studied. The technique was shown to be capable of handling the 3351 sera studied and thus to be a useful screening test to assess the immune status of large populations. The results demonstrated some of the effects on the human population of the successful bovine brucellosis eradication programme.