A surveillance programme is described which is intended to assess the effects of influenza virus infections on communities at large by collating influenza virus isolations and consultations for respiratory infections from general practices with new claims for sickness benefit and deaths from all causes. Particular importance is attached to relating virus isolations to symptomatic respiratory disease seen in practices of known age and sex structure.

The distribution in the environment of Naegleria fowleri, the causal agent of primary amoebic meningoencephalitis has been investigated in this study. N. fowleri was isolated only from a thermally polluted canal. These amoeboflagellates were not isolated from another thermally polluted canal in the neighbourhood indicating that, apart from high temperature, other factors are involved in the selective proliferation of N. fowleri. This species was absent in all other samples originating from two canals, a stream, two lakes, several reservoirs and slow sandfilters of a water supply service and also a water distribution network. Many other amoebae able to grow at 42° C. were found in different places. Most of the N. fowleri strains isolated were not virulent for mice, although they showed all the characteristics of the pathogenic strains.

Measurements have been made of the extent of air exchange between patient rooms in a fully air-conditioned hospital using a tracer-gas method.

When the rooms were ventilated at about six air changes per hour, had an excess airflow through the doorway of about 0.1 m.3/sec. and the temperature difference between rooms and corridor was less than 0.5° C., concentrations of the tracer in rooms close to that in which it was being liberated were 1000-fold less than that in the source room. This ratio fell to about 200-fold in the absence of any excess airflow through the doorways. Considerable dilution took place along the corridors so that the concentration fell by around 10-fold for every 10 m. of corridor.

Experiments were conducted simultaneously with gas and particle tracers to determine the relative loss of particles between source and recipient sites in the hospital ward units. The magnitude of this loss could be accounted for by the assumption of sedimentation from well-mixed air masses during the time required for movement between source and recipient sites. As a consequence of this loss the degree of isolation between patient rooms for airborne particles was between 4 and 25 times greater than that for gaseous contamination, which reflects the actual transport of air between the rooms.

The design and construction of portable spinning-disk particle generators suitable for field studies is discussed.

A mathematical model is described for the transport of gaseous or airborne particulate material between rooms along ventilated passageways.

Experimental observations in three hospitals lead to a value of about 0.06m.2/sec. for the effective diffusion constant in air without any systematic directional flow. The ‘constant’ appears to increase if there is any directional flow along the passage, reaching about 0.12 m.2/sec. at a flow velocity of 0.04 m./sec.

Together with previously published methods the present formulae make it possible to calculate the expected average amounts of gaseous or particulate material that will be transported from room to room in ventilated buildings in which the ventilation and exchange airflows can be calculated.

The actual amounts transported in occupied buildings, however, vary greatly from time to time.

Groups of patients with lepromatous and tuberculoid leprosy and hospital staff from six leprosaria in East Africa and ‘non-contact’ groups of villagers or staff from general hospitals have been skin tested with 10 reagents. These were prepared by ultrasonic disintegration from M. tuberculosis, M. duvalii, M. chelonei and 7 other species identified in the Ugandan environment. Comparisons were made of the percentages of positive reactors in each study group for each reagent. The ‘specific’ defect of lepromatous patients was found to apply to a variable extent to six of the species tested, but not to M. tuberculosis, M. avium or M. ‘A*’. The defect applied most noticeably to M. nonchromogenicum and M. vaccae, suggesting that they are more closely related to M. leprae than are the other species tested. The reagent Chelonin produced unexpected and anomalous results in the lepromatous group. It is suggested that this was due to an unusually slow clearing of Arthus' reaction.

Twenty-eight pigs died in an outbreak of streptococcal meningitis in an East Anglian herd. Most were 10–14 weeks old. The outbreak lasted from January to April and was finally controlled by antibiotic therapy. A similar number of losses had occurred in the previous year though no diagnosis had then been made.

The causal agent appeared to be a haemolytic streptococcus belonging to group D and provisionally designated Streptococcus suis type 2. It is probably identical with de Moor's group R streptococcus which causes a similar disease in the Netherlands. It is serologically distinct from Streptococcus suis type 1 which causes meningitis in piglets. Type 2 infection in pigs appears to be widespread in England and Wales and to occur in animals up to the age of at least 14 weeks.

A comparison is drawn between Str. suis meningitis in pigs and group B streptococcal meningitis in human infants.

Intravenous provocation (IVP) tests demonstrated that hydroxypropylmethylcellulose (MC) was able to elicit anaphylactic signs in cattle vaccinated with foot-and-mouth disease (FMD) vaccine produced at one centre but not with similar vaccine produced at another. The former vaccine also provoked serum reagins which were demonstrated by passive cutaneous anaphylaxis (PCA) tests in goats.

Reaginic sera which reacted specifically with MC were used in PCA tests to screen samples taken serially from the vaccine production lines. The reactions observed suggested that a substance with MC or similar specificity was present in the antifoaming agent routinely added to vaccines.

An investigation into the cause of bacterial contamination of bottles of non-injectable water has been reported. A method of monitoring such bottles has also been described. The roles played by autoclave spray-cooling water and inadequate bottle seals in the contamination of fluids have been examined. Possible methods of reducing the risk of contamination are discussed and the design of an improved method of closure of sterile bottled fluids is stressed. Bacteriological examination is shown to be a more accurate index of the true rate of contamination than measurement of dye concentrations of bottle contents.

The results of testing sera from 111 patients with rubella-like illnesses and 283 contacts of patients with rubella-like illnesses are described. A sensitive haemagglutination-inhibition test was used in conjunction with fractionation of serum proteins when this was indicated. It was concluded that the testing of serum protein fractions for IgM and IgG rubella antibody greatly increased the effectiveness of laboratory diagnosis. Evidence is presented that during the study period subclinical rubella was relatively uncommon in adults and that the accuracy of clinical diagnosis was high.

The Limulus test detected endotoxins in the plasma of burned and unburned mice infected with different species of gram-negative bacteria. Individual strains of different species of gram-negative bacteria produced different amounts of endotoxin in the plasma of infected mice. Plasma from mice given lethal infections showed very high concentrations of endotoxin. Low concentrations of endotoxin in the plasma were tolerated by mice but high concentrations were invariably fatal. A polyvalent pseudomonas vaccine reduced endotoxin in the plasma of mice given lethal infections of Pseudomonas aeruginosa.

Bacteriological tests alone are not capable of predicting the keeping quality of cream, since taints can develop which are due to non-bacterial action. When spoilage is due to bacterial growth, the water agar test was found to be more accurate than the other tests that were examined.

The names Citrobacter koseri, Levinea malonatica and Citrobacter diversus are synonymous. As a result of the study of representative strains of these organisms an antigenic scheme comprising seven O antigens has been proposed. The examination of a further 165 strains from clinical sources suggests that an additional seven antigens should be included in the scheme. The serological and biochemical reactions of the test strains for all 14 O antigens are described.

165 strains of Citrobacter koseri isolated from clinical specimens were studied and their biochemical reactions determined. They were examined serologically by means of a scheme consisting of 14 O antigens. The sources of the clinical specimens were tabulated and the epidemiological information was summarized. The clinical significance of these findings is discussed.

The faecal flora of 55 children (aged 8 days to 8 years) and 16 adults was determined. All the children were artificially fed from birth. The faecal flora of the youngest age group was generally less complex and less predictable than that of adults. Some bacterial groups commonly found in adult stools, for example bacilli, lactobacilli and yeasts, were rarely found in the youngest infants. Most of the changes towards the adult pattern took place between 4 and 12 months. The faecal flora of children aged 1–4 years generally resembled that of adults, although lactobacilli were still infrequently isolated.

Sixty-three samples of the more solid material (sludge) separated from the effluent plants of dairy factories were examined for the presence of salmonellas and brucellas. Salmonellas were isolated from two samples (S. heidelberg. [1]; S. indiana [1]). No brucellas were isolated. None of the samples supported the growth of S. dublin. Salmonellas added to effluent sludge at a concentration of 106 organisms/ml, survived less than 70 days.

The sludge from dairy factory effluent plants does not appear to be a source for the spread of salmonellosis or brucellosis.

The serological relationship between Brucella spp., Yersinia enterocolitica IX, and the group N salmonella serotypes S. godesberg, S. landau, S. morehead, S. neusdorf, S. soerenga and S. urbana was examined using agglutination, antiglobulin, complement fixation, immunodiffusion and fluorescent antibody methods.

Antisera to the group N salmonella serotypes all reacted to significant titres in agglutination and complement fixation, but not antiglobulin or immunodiffusion tests with smooth brucella antigens. These antisera also reacted in agglutination, but not antiglobulin, tests with Y. enterocolitica IX. They did not react significantly in any tests with rough brucella antigens.

Conversely, antisera to smooth Brucella spp. agglutinated group N salmonellas to low titre and Y. enterocolitica IX to titres similar to those given against the homologous strain. Antiserum to Y. enterocolitica IX on the other hand reacted with smooth brucella antigens to high titre in agglutination, complement fixation and antiglobulin tests, and with the group N salmonella antigens to substantial titres in agglutination tests.

In direct fluorescent antibody tests, smooth Brucella strains and Y. enterocolitica IX reacted strongly with FITC-labelled antibody to Br. abortus whereas the group N salmonella strains reacted weakly.

In tests with monospecific antisera to the A and M determinants of Br. abortus and Br. melitensis respectively, Y. enterocolitica IX reacted only with the antiserum to the A determinant whereas group N salmonellas reacted to low titre with both A and M antisera.

The results of cross-absorption tests confirmed this relationship and suggested that the O30 antigens of group N salmonella serotypes contained antigenic determinants similar to, but not identical with, the antigenic structure shared by smooth Brucella spp. and Y. enterocolitica IX.