In a group of 32 adult volunteers given subunit influenza virus vaccine containing 250 international units (i.u.) of A/Victoria/3/75, 250 i.u. of A/Scotland/ 840/74 and 300 i.u. of B/Hong Kong/8/73, there were substantial increases in the geometric mean homologous haemagglutination-inhibiting (HI) antibody titres. There was also substantial boosting of the antibodies to the earlier variants of the Hong Kong (H3N2) series and to a later variant of the Asian (H2N2) series. There was no boosting of antibodies to the A/FM/1/47 strain, a representative member of the H1N1 series, but two individuals showed substantial rises to A/PR/8/34 (H0N1).

There were increases in the HI titre of antibodies cross reactive with two recent isolations, A/Texas/1/77, and A/Victoria/35/77, but the majority of vaccinees failed to reach antibody titres likely to be protective against such strains.

Cooked chicken was allowed to spoil in a normal kitchen refrigerator (variable temperature) and at a standard4 °C. After 10 days' storage, bacteria were isolated from the chicken. It was found that the numbers oforganisms at variable refrigeration temperature were tenfold higher than those at a uniform 4 °C. In an attempt to find the sources of contamination, swabs were made of different areas of the kitchen. Many of the bacteria isolated from the spoiled chicken, were also isolated from the kitchen environment.

When pure cultures of organisms isolated from spoiled chicken were inoculated into sterile cooked chicken and held at 4 °C, the main spoilage organisms were found to be Pseudomonas putida and Aeromonas hydrophila, which were also isolated from the refrigerator where the chickens were stored in the kitchen.

Aeromonas hydrophila was found in significantly high numbers on plates, cutting knives, chopping boards and cold water taps.

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.

Replication of vaccinia and monkeypox viruses was impeded in the presence of 5-bromodeoxyuridine (BUdR) in RL-33 cells derived from rabbit lung tissue. The different degree of inhibition was found among strains of those viruses, in which it was evident that five strains (CV-1, Lister, IHD, Dairen-I and Ikeda) of vaccinia viruses resulted in more reduced yields of infectious virus than four strains (Sen-19, Orang Utan, Copenhagen and Sierra Leone) of monkeypox viruses. There was also strain variation in BUdR sensitivity within vaccinia viruses but not in the case of monkeypox viruses.

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 relative immunogenicity in mice of whole influenza virus, and virus split with different disrupting agents, was compared. Using the single radial immunodiffusion test to estimate the haemagglutinin antigen concentration in different virus preparations, it was found that, in general, split virus preparations induced substantially lower titres of HI antibody in mice than whole virus after one or two injections of the antigen.

A house to house survey was done from October 1972 to March 1974, covering 52952 individuals of urban population at Lucknow and 50156 individuals of rural population of Unnao district, to find out the incidence of polio-like paralysis in our population. Among 12874 urban children up to 8 years old 8·2/1000 had polio-like paralysis while 4·6/1000 children of the rural population of 13554 children were affected. The incidence was significantly higher in the urban population. In the preschool age group almost 1 out of every 100 children was affected. A higher number of children were affected during 1968–9 and 1971–2, though it did not reach epidemic proportion. The findings show that paralytic polio is a serious problem in our country where poliomyelitis is endemic: this is contrary to the views generally held so far.

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.

Samonella johannesburg has been prevalent in Hong Kong since 1973 and most strains were resistant to a multiplicity of antibiotics. The susceptibility of S. johannesburg strains isolated in a 5-year period from 1973 to 1977 to eight antimicrobial drugs including ampicillin (A), streptomycin (S), tetracycline (T), chloramphenicol (C), Kanamycin (K), sulphadiazine (Su), trimethoprim (Tm) and gentamicin (G) was tested by the agar dilution method. The proportion of strains resistant to chloramphenicol and ampicillin increased steadily during the 5-year period while those resistant to tetracycline decreased dramatically. This change was associated with an alteration of predominant patterns of antibiotic resistance: strains with the resistance pattern A.S.T.C.K.Su predominated in years 1973, 1974 and 1975 while those with the resistance pattern A.S.C.K.Su predominated in years 1976 and 1977. Analysis of the resistance patterns of S. johannesburg strains isolated from the same cases showed that the resistance pattern A.S.C.K.Su was more stable, and changed less frequently to other patterns of resistance than strains with the resistance pattern A.S.T.C.K.Su. In donor salmonella strains with the A.S.T.C.K.Su resistance pattern, transmissible factorscarrying resistance to A.S.T.C.K.Su in to to, to A.S.T.C.Su, A.T.C.K.Su and to A or T alone were demonstrated. In donor salmonella strains with the A.S.C.K.Su resistance pattern, transmissible factors carrying resistance to A.S.C.K.Su in toto and to A.S.K.Su were detected. The significance of the carriage of such transmissible resistance factors by this Salmonella is briefly discussed.

The possible sources for the epidemic of bluetongue in Portugal at the beginning of July 1956 were examined. Introduction through authorized importation of domestic or wild ruminants was not feasible, since no cattle, sheep or goats were imported and the wild ruminants were confined to Lisbon Zoo, which was too far from the initial outbreaks. Weather maps were examined to see if the wind could have carried infected Culicoides midges from North Africa. On 21 June 1956 infected midges in Morocco could have been taken offshore by southeast winds and then carried by south winds unusual at that time of year to the south coast of Portugal. The 200–300 km sea crossing would have taken some 10 h and been by day when air temperatures near the sea surface were about 18–20 °C. Bluetongue had not been reported at that time in Morocco, and the possibility of the presence of the virus in Moroccan animals without clinical signs is discussed.

Summary Surface waters in 14 selected sites were examined for the presence of salmonella using modified Moore's swabs. The sites included an upland impounding reservoir, 3 rivers and 10 streams within Lancashire and Cheshire, selected because of their accessibility to farm livestock. Salmonellas were isolated from 22 out of the 57 swabs examined representing 10 sites. The probable source of pollution was shown to be sewage or farm effluent and an examination of sites over a wider area may be expected to produce similar results.

The significance of these findings is discussed in relation to the epidemiology of salmonella infections and the possible disinfection of effluent discharges.

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.

The anticoagulant rodenticide brodifacoum was tested against house mice (Mus musculus L.) infesting farm buildings. In six trials, treatment success was assessed from the results of census baitings conducted before and after treatment. With 0·005% brodifacoum in canary seed/corn oil bait, the control achieved ranged between 92·7% and 100%, mean 98·8%. Two mouse populations were eradicated in 3 to 4 weeks but a few individuals survived each of the other four treatments which lasted 6 weeks. The effectiveness of brodifacoum against mice is compared with that of 0·1% calciferol and 0·025% warfarin in combination. It is concluded that brodifacoum and calciferol/warfarin are equally effective in controlling M. musculus but that brodifacoum treatments need to be conducted fora relatively longer period.

This paper presents the hypothesis that some cases of cholera might be due to effluent discharge from aircraft. The theoretical case is borne out by inspection of data on the physical conditions pertaining between high altitudes and ground level. A study of the distribution of isolated outbreaks and single cases of disease and their relation to major airline routes showed a reasonable correspondence. Sporadic outbreaks of cholera in Europe between 1970 and 1975 were found to lie within the flight paths of regular airline services from Calcutta, where cholera is endemic, to the Northern Hemisphere. Laboratory studies on the stability of Vibrio cholerae to conditions likely to be encountered in droplets falling from high altitude to the ground suggested that significant numbers of organisms might survive. It should be noted that in this study no account was taken of the effect of ultra-violet light on viability and it is known that at high altitudes the ultraviolet light component of solar radiation is much higher than at ground level. Results of experiments where small numbers of organisms were inoculated into relatively poor media showed that rapid growth ensued and that sufficient organisms were produced to give an infective dose of Vibrio cholerae in 1–10 ml/fluid. It could be concluded that human infection could easily occur by ingestion of fluids such as milk or soup which had some time earlier received a fortuitous but slight contamination from the air. Investigation of one disinfectant (chloramine T) showed that it reacted rapidly and in a complex manner with peptone. One effect of this reaction was the elimination of bactericidal activity and it seems likely that, as at present employed, chloramine T is of doubtful value in aeroplanehygiene. One important conclusion that arises from this work is that if cholera can be spread, even only occasionally, by effluent from aircraft then close investigation should be made of the possibility of other bacteria and viruses being spread in a similar way.

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.

A series of 2092 cultures of Salmonella typhimurium isolated from human, animal and other sources in 57 countries were differentiated into 204 phage types and 19 primary and 147 full biotypes. Different biotypes belonged to the same phage type and different phage types to the same biotype, so the combination of typing methods differentiated strains more finely than either method alone: 574 different ‘phage type/biotypes’ were distinguished in 1937 cultures belonging to the 204 recognized phage types.

The combination of biotyping with phage-typing was valuable in studying the phylogeny and spread of epidemic strains by distinguishing clones of different biotype within the same phage type and by confirming the relationship between cultures isolated from widely dispersed clones and that between cultures isolated before and after a clone had undergone variation in phage type, biotype, colicin type or antibiotic-sensitivity pattern.

A widespread outbreak of infection with S. typhimurium phage type 141 in Scotland comprised independent dissemination of three clones of different biotypes, if, 9f and 31bd. During its epidemic spread in cattle in Britain between 1962 and 1969, another strain underwent variations in phage type (type 44 to type 29), biotype (type 26a to types 26d, 26bd, 26dgi, 26dz and 26i) and antibiotic sensitivity. A group of 275 non-fimbriate, non-inositol-fermenting and non-rhamnose fermenting (FIRN) strains, particularly associated with avian infections and thought to be clonal in origin, contained 27 phage types and 22 full biotypes in the primary biotypes 29–32.

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.

Between 1969 and 1972 three quality control studies were set up to investigate the variation in results that was occurring between and within laboratories performing routine tests for the diagnosis of rubella infection. No attempt was made to standardize the test in these studies, and a wide range in titres of sera was reported. The aims of the present studies were:

(i) to investigate in greater detail whether results were more reproducible between laboratories if test sera were compared with control sera of known potency and the results given in international units of activity, and

(ii) to ascertain whether results between laboratories would be more reproducible if a standard test procedure was used.

Eleven laboratories participated in testing 38 sera on three separate occasions by a prescribed standard technique and by that used routinely in each laboratory. Eight of the 38 sera consisted of four pairs of duplicate samples.

Analysis of results of the study showed that the reproducibility between laboratories was substantially improved when the test sera were compared with a control serum of known potency and when a standard test procedure was used.

Variation in results between laboratories was least when a control serum of low rather than high potency was used. Variation within laboratories can be reduced by increasing the number of times the control and test sera are tested.

Since the rubella antibody content of the British Standard anti-rubella serum is expressed in international units, the potency of the control and results of test sera should also be expressed in such units.

The development of a Klebsiella serotyping method by counter-current immunoelectrophoresis (CIE) is described.

Antisera were prepared against the capsular antigens of 72 type strains and tested for the specificity and strength of their precipitin reactions with antigens from homologous and heterologous serotypes. All antisera produced strong reactions with their homologous antigen: when diluted to titre 63 were highly specific, 3 cross-reacted strongly and 6 weakly with one other antigen. Pools of antisera for screening purposes were constructed on the basis of common cross-reactions: component serotypes of each pool could be detected strongly and specifically.

The technique is simple to perform, fairly rapid, and economical in the use of antisera. Results can be read easily and quickly and the intensity of cross-reactions compared directly. The technique appears to be more specific and is less time consuming than the Quellung method, but further assessment of its efficacy in typing routine clinical cultures is necessary.

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.