Unadapted bovine ephemeral fever (BEF) virus was isolated from cattle blood after intravenous inoculation into chicken embryos. Infected embryos died or hatched as abnormal chickens. The chick embryo was slightly less sensitive to unadapted BEF virus than were Vero cell cultures, but the use of embryos avoids the several blind passages that are required to isolate BEF virus in unweaned mice. Chick embryos were considerably less efficient than Vero cell culture or unweaned mice in detecting Vero cell-adapted and mouse-adapted BEF virus respectively.

Viraemia was demonstrated in chicken embryos at 1–4 days and in one-day-old chickens at 1–3 days after intravenous inoculation of BEF virus. BEF virus was demonstrated by isolation and by immunofluoresence in heart, brain, lung and liver of chicken embryos at 1–5 days and in lung and liver of one-day-old chickens at 1–2 days, after intravenous inoculation. The isolated viruses were confirmed as BEF virus by neutralization with immune mouse ascitic fluid. BEF neutralizing antibodies were produced in 4-week-old and adult chickens after intravenous inoculation with BEF virus.

Polyoma virus was recovered from the air of an animal laboratory housing mice infected with the virus. Air samples were obtained by means of a high volume air sampler and further concentrated by high speed centrifugation. Total concentration of the air samples was 7·5 × 107. Assay for polyoma virus was by mouse antibody production tests. Airborne polyoma virus was detected in four of six samples.

The epidemiological and drug susceptibility data on whooping cough suggested a possibility that Bordetella pertussis converts in some way to Bordetella parapertussis. To prove this, B. pertussis strain 75 was treated with N-methyl-N'-nitro-N-nitrosoguanidine and a mutant resistant to staphcillin V and eight mutants resistant to trimethoprim were isolated. The staphcillin V-resistant mutant of B. pertussis agreed with all of the criteria of B. parapertussis and the trimethoprimresistant mutants also agreed with many of these criteria. Thus, a hypothesis is presented that B. parapertussis is a mutant of B. pertussis which appeared in nature probably by a selective pressure of antibiotics.

Neutralization tests for poliovirus antibodies were carried out on 74 patients in an adult mental deficiency hospital: 37 patients with Down's syndrome and 37 non- Down's mental defectives. The distribution of antibody titres to poliovirus types 1, 2 and 3 did not differ significantly between the two groups. Most patients had antibody to at least one poliovirus typebut less than a third had antibodies at a titre of 1/8 or greater to all three types. The low level of poliovirus immunity in this population may be of epidemiological importance.

Agglutinating antibodies to somatic ‘O’ and flagellar ‘H’ antigens of S. dublin were measured in the serum of 43 pregnant heifers before intravenous or oral infection with S. dublin and in the serum of 21 uninfected control animals. The data from these animals were analysed statistically and a titre of 1/80, to both antigens, has been interpreted as of doubtful significance and a titre of 1/160 to both antigens, has been interpreted as significantly raised. Animals in which fetal infection occurred after challenge by either the intravenous or oral route developed significant increases in ‘H‘O’ titres indicating the value of measuring ‘H’ titres in the diagnosis of S. dublin abortion. In animals which were infected orally and in which infection appeared to be confined to the alimentary tract the ‘H’ titre did not become significantly raised. Lack of correlation between antibody titres and faecal excretion of S. dublin and persistence of infection in carcasses confirms that the serum agglutination test is of no value in detecting latent carriers.

Between June 1976 and August 1977 faeces were collected from 599 wild British birds caught during ringing operations at two sewage treatment works in south-east England. Samples were incubated with selenite-F broth to detect the presence of Salmonella. Salm. anatum was isolated from one bird, a Dunnock Prunella modularis an incidence of O.17 % of the total birds examined and 3.23 % of the Dunnocks. Comparisons are drawn with previously reported studies and it is suggested that sewage treatment works play little part in the transmission of Salmonella infections to wild birds feeding there.

A study of respiratory diseases in the semi-isolated community of Port Chalmers, New Zealand, began in April 1973. The intensive surveillance of a selected group of 26 families involved the weekly reporting of illness, the collection of specimens for virus, Group A streptococci and Mycoplasma pneumoniae isolation and the collection of sera at 6-month intervals. A total of 956 illnesses were reported during 32 months. The median number of illnesses per year were: infants 4·4, children 2·5, female adults 2·4 and male adults 2·0. Of all these illnesses, 57% were upper respiratory, 31% were lower respiratory and 9% were enteric. The severity of these illnesses was not greater than would be expected in open communities. Surveillance by pathogen isolation only of the whole community through the patients in the general practice was carried out concurrently.

A total of 640 nasopharyngeal swab specimens were collected from which 161 viruses, 47 Group A streptococci and 2 M. pneumoniae were isolated. The overall isolation rate was 33%. The similarities between the epidemiological patterns of respiratory disease in the open community and the isolated community are discussed.

During the first year of a study of respiratory disease in the semi-isolated community of Port Chalmers, New Zealand, an epidemic of clinical influenza occurred from which the variant influenza A/Port Chalmers/1/73 (H3N2) was isolated. Within a selected group of 26 families, 59 (46%) members had clinical or laboratory evidence of infection. During intrafamilial spread the infection frequency was highest for school-aged children (77%), followed by female adults (67%), infants (64%) and male adults (41%). The index infection in each family was a school-age child on 10 occasions, suggesting the role of this age group in the transmission of influenza A in this community. The secondary attack rate (SAR) of 58·3% was higher than expected.

In sera taken before the 1973 epidemic, 59% of family members had detectable HI antibody and 25% NI antibody to A/England/42/72 while 38% had detectable HI antibody and 8% NI antibody to A/Port Chalmers/ 1/73. The relation between pre-existing antibody and infection frequency is discussed.

Echovirus 11 in the presence of fetal calf serum was exposed to six commonly used disinfectants for times of 10, 20 and 30 s. At the end of such exposure times, skim milk neutralized disinfectant activity and residual virus was assayed using the plaque technique. The six disinfectants studied were Javex, sodium hydroxide, ethanol, Wescodyne, One Stroke Ves-Phene, and Sonacide. Although 0·25% (w/v) sodium hydroxide and 95% (v/v) ethanol were equally virucidal and significantly more so than the other four disinfectants, causing 106 reduction in 20 s, they may not be practical to use in many instances. Javex at a dilution of 1/50 (1200 parts/106 chlorine) proved to be virucidal causing 103·5 reduction of echovirus 11 in 30 s. Wescodyne (1/50) and undiluted Sonacide were relatively ineffective causing 10 reduction or less of echovirus 11 in 30 s. One Stroke Ves-Phene (1/50) was ineffective causing no significant inactivation in 30 s.

Three hundred and twenty-two strains of Bacteroides fragilis isolated from infected patients at three different hospitals were tested against 20 type specific B. fragilis antisera using the tube agglutination technique. Of these strains 41·3% were assigned to a single O-serotype, a further 20·5% were agglutinated by several antisera and could not be classified and the remainder showed no reactions. Three different serotypes were prevalent in the three hospitals and minor geographical variation was observed.

No correlation was found between serotypes and the origin of infection, but those from the blood were the most readily typable strains. No correlation was found between serotypes and biotypes of B. fragilis.

Particles released into the air by wringing the hands together were collected in a slit sampler before and after washing with bar soap, with three surgical scrubs, and after rubbing them with a spirit-based lotion. The particles were identified, their number estimated, those that bore bacteria counted, and the bacteria themselves classified. It was found that there was a significant increase, averaging 17-fold, in the number of particles carrying viable bacteria released after washing with soap. The increase in bacterial dissemination was suppressed if a surgical scrub was used in place of soap, or when the lotion was used without washing. The number of skin squames released increased by 18-fold or more after washing with soap or a surgical scrub, but not after using the lotion. This suggests that a surgical scrub should be used more widely in clinical practice, and that a spirit-based hand lotion might with advantage become a partial substitute for handwashing, particularly in areas where handwashing is frequent and iatrogenic coagulasenegative staphylococcal infection common.

A microneutralization test for serotyping of FMD viruses is described. It is based on earlier observations by Booth, Rweyemamu & Pay (1978) that dose-response relationships in quantal microneutralizations often deviated from linearity. The typing test described therefore utilizes undiluted virus preparations. In about 90% of samples a positive typing was obtained in contrast with about 50% for the complement fixation test. The test was also found to be susceptible to minimal quantities of heterotypic viral contamination.

For strain differentiation the microneutralization test was carried out as a checkerboard test. When compared with the complement fixation test it was found to be more specific. The necessity to utilize virus-neutralization test systems for comparing (FMD) virus strains particularly for the purpose of vaccine selection is emphasized. The two dimensional microneutralization test has been applied to a study of comparing FMDV vaccine strains for Europe, South America, the Middle East and East Africa.

Nasal swabs were taken from 492 babies born consecutively to residents of two South Wales towns soon after their discharge from maternity hospitals. Staphylococcus aureus was isolated from 352 babies (72%) and in 79 (22%) of these it was resistant to at least one antibiotic. By the time these babies were a year old the prevalence of both sensitive and resistant strains had fallen, so that only 12% still carried nasal staphylococci, but 64% of these organisms were then resistant to penicillin. Administration of penicillin to the baby seemed to be a more important factor in selecting resistant organisms than other antibiotics given to the baby, any antibiotic treatment to other members of the household, or discharge from hospital.

The results presented in this paper confirm the existence of two types of tetracycline resistance in Shigella sonnei. One group of strains had a high level of resistance to tetracycline and oxytetracycline, with a variable level of minocycline resistance. The second group had a lower level of tetracycline resistance and were sensitive to minocycline. After conjugation with E. coli K12 the selected E. coli transconjugants had the same levels of resistance as the parent Sh. sonnei strain, with one exception. Sh. sonnei 87 was resistant to a high level of tetracycline, but was able to transfer only low level resistance. It is suggested that Sh. sonnei 87 carries two plasmids: pSU1, a conjugative plasmid conferring a low level of tetracycline resistance, and pSU2, a non-conjugative plasmid which confers a high level of resistance to tetracycline.

Five methods for the enumeration of micro-organisms in food (pour plate, surface spread plate, surface drop, agar droplet, and microdilution) were used in parallel to examine 100 samples selected from a wide range of food products.

Statistical analyses of the results showed that the regression and correlation coefficients between the methods were highly significant; the lowest correlation coefficient derived for any pair of methods was 0·979. A variation in count between the methods of less than 0·5 log10 cycles was given by 98% of the samples.

Analysis of the operation times and material requirements of each method showed that substantial savings in cost, time, space and support labour were achieved with the microdilution and agar droplet techniques as compared with the conventional pour plate and spread plate methods.