A trial of an experimental live influenza B vaccine has been described.

The virus it contained was active and produced infections, antibody rises and clinical reactions.

Second and third vaccinations had much less effect than the first. Resistance to revaccination was only partially reflected in the serological response.

It seems that another factor, probably local antibody, exerts a considerable influence on resistance to infection with influenza viruses.

We are greatly indebted to Dr P. G. Higgins of the Public Health Laboratory, Cirencester, who went to much trouble to provide us with specimens from patients with influenza; to Dr H. G. Pereira of the National Institute for Medical Research for the antigenic analysis of the vaccine virus; to Messrs Sankey Ltd., Bilston, Wolverhampton, for their unfailing courtesy and forbearance throughout the trial; to the volunteers for their enthusiastic co-operation in the face of some discom forts; and to Messrs Pfizer Ltd., Sandwich, for originally providing facilities for the preparation of the vaccine.

In particular we wish to record our gratitude for the invaluable technical help of Miss Pamela Ball of the Common Cold Research Unit, Mrs Maria Gregory of the Bacteriology Department of Liverpool University, Mrs L. Johnson of the Virus Laboratory of New Cross Hospital, Wolverhampton, and Mr A. Westoby, an assistant in the practice of Dr Tyler.

Investigations of the biological properties of tick-borne encephalitis viruses immediately after isolation from naturally infected Ixodes persulcatus from Western Siberia has revealed their different pathogenicity for monkeys and mice. Strains highly pathogenic for mice on extraneural inoculation and for rhesus monkeys on intracerebral inoculation have been isolated, but also strains with a low extraneural pathogenicity for mice and a complete non-pathogenicity or a mild pathogenicity for monkeys on intracerebral inoculation.

The viruses have been classified into three main groups by their virulence for mice and monkeys, and their ability to grow in tissue culture at 40° C. and the findings are summarized in Table 6. Group I included viruses highly virulent for mice by any route of inoculation, which caused fatal paralytic disease in monkeys, and which grew well in chick embryo culture at 40° C.

Group II strains also had a high virulence for mice, but in monkeys caused milder disease with a peculiar clinical course indicative of primary damage to the cerebellum. About half of the infected monkeys recovered completely or with mild sequelae (ataxia, pareses of the limbs). This group grew moderately well in chick embryo cultures at 40° C. Groups I and III differed essentially in their virulence for mice by subcutaneous inoculation, and virulence for monkeys decreased distinctly with transition from group I to group III. Group III strains showed a lower reproduction rate at 40° C. In chick embryo culture than group I. Groups I and II showed good correlation between extraneural pathogenicity for mice, pathogenicity for monkeys by IC inoculation, and growth rate in chick embryo cultures at 40° C.

Group I strains were isolated chiefly from foci with a high TBE morbidity and the strains of groups II and III in foci with sporadic cases. It is, however, highly probable that in any tick-borne encephalitis focus several variant strains of differing virulence exist.

Recent experience of vaccinating volunteers with naturally attenuated group III strains suggests that safe and effective live vaccines can be developed against tick-borne encephalitis. Vaccines against many other arbovirus diseases can probably also be derived from naturally occurring strains of virus isolated from arthropods in areas of low disease but high infection rate. This approach looks more promising than the usual approach of attempting to develop attenuated strains from highly virulent strains.

1. Foot-and-mouth disease broke out on three pig farms of the Spetchley area of Worcestershire after the virus had been carried to them in skimmed milk.

2. A study of the natural features of the area and of the climatic conditions during the outbreak show that the wind could have carried the virus from one or other of these three to twenty-six others of the total thirty-two farms infected.

3. Bringing the cattle from the fields and keeping them in their sheds offered no protection. Nine farmers did so but the only effect was that the onset of infection was delayed for a day or so.

4. The direction in which cow-sheds faced likewise made no difference. Openings in the walls for ventilation obviously allowed virus to be carried inside.

Mr J. S. Needham, M.R.C.V.S., first showed me that the wind could have been responsible for the spread of the disease in the Spetchley outbreak. I am glad to be able, after my study, to support his view. I am indebted to Mr V. Harris, Officer-in-charge, R.A.F. Meteorological Station, Pershore, Worcestershire, for the climatic details.

A tryptone-yeast extract medium enriched with glucose and serum incubated anaerobically at 41° C. was found to give a good yield of Staphylococcus aureus from air samples while suppressing the growth of 70–80% of the other airborne bacteria.

Our thanks are due to Miss S. M. Taber and Miss Patricia Wall, the Sisters in the wards where the air samples were collected, for their help. The investigation was financed from the Ministry of Health grant to St Mary's Hospital for the support of clinical research.

The inactivation kinetics of CELO virus were studied in the presence of 1/4000 formaldehyde. Inactivation of the virus by formaldehyde at 4° C. was not complete after 14 days incubation. Formaldehyde inactivation at 36° C., however, was rapid and no virus was detected after 24 hr. incubation.

Neutralizing antibody to CELO virus was detected in 20–88% of sera tested from five flocks of hens. This suggested dissemination of the virus in England and Scotland. However, no CELO virus neutralizing antibody at a serum dilution of 1/8 was detected in 142 normal human sera or in 229 sera from persons who had been immunized with egg grown, inactivated influenza virus vaccine.

We would like to thank Professor C. H. Stuart-Harris and Drs J. E. Wilson, D. A. Martin and D. Breeze for their help and their criticisms of the manuscript.

Dr G. C. Schild kindly supplied a number of the human sera used in the study. The study was financed in part by the National Fund for Research in Poliomyelitis and other Crippling Diseases and by the British Empire Cancer Campaign.

The relationship of pre-operative nasal and skin carriage of Staphylococcus aureus to wound colonization and sepsis was studied in 269 patients. Thirty-seven per cent of 96 carriers developed wound colonization as compared to 16 % among non-carriers (a statistically significant difference). The wound sepsis rates were 17 % and 9 % respectively. The combination of nasal and skin carriage was an important factor, since the sepsis rate among skin carriers (most of whom were nasal carriers as well) was 22%. Among carriers, the homologous strain was recovered from the majority of wound colonizations and from all instances of wound sepsis. A carrier strain also was recovered from 52% of the wounds colonized and from 50% of septic wounds in the entire study group. Profuse nasal carriage resulted in a significantly greater number of septic wounds (31%) than sparse carriage (9%). Wound cultures before closure, and skin from the initial incision site only once yielded a patient's carrier strain or a strain of Staph. aureus that was later recovered from the wound. The results indicate that measures designed to control the carrier state or to isolate the wound from the external environment should reduce wound sepsis by approximately one half.

Excellent technical aid was furnished by Eleanor Ford, R. N., Edith E. Silverman, Adrienne Marus, M. S., and Patricia Welch.

Secondary schoolchildren in England were asked to assess thermal conditions in winter according to subjective sensations of warmth. Conditions of normal occupancy and activity were maintained and optimum conditions established in terms of four thermal measures by regression analysis of over 2500 assessments by boys and girls. The comfort zone was delineated as that within which 60% of the children were comfortable and in terms of the commonly used dry-bulb temperature this zone lay between 59 and 70° F. in still air. The optimum conditions for children were also compared with those recommended for adults.

Salmonella senftenberg was isolated from 168 patients and staff of a general hospital whereas it was isolated from only seven other sources (four of which were unquestionably associated with the hospital) in the surrounding area during the same period. It was isolated in the hospital in 19 of the 48 months of the period. Two clear-cut episodes were recognized against a background of sporadic isolation. Four-fifths of the patients and staff excreting the organism had no symptoms. Only two are known to have been severely ill, though in some patients very ill for other reasons life may have been shortened a little.

The original source of the organism, whether from the farm or from raw materials such as meat or poultry, was not found.

Serum specimens collected in 1966 from individuals of different age groups were studied for the presence of haemagglutination inhibition (HI) antibody to four influenza viruses. All sera were from individuals of blood group A or O and in no instance was the incidence of antibody to a virus strain significantly greater for persons of blood group O compared with similar aged individuals of blood group A. This finding for HI antibody to A 2/Singapore/1/57 is different from similar studies of serum specimens collected in 1961–3. It is suggested that the change in the immune status of a population, with reference to blood-group status, is due to repeated exposure to infection; this changing pattern of immune status is discussed.

Similar studies of HI antibody to adenovirus type 3 and 7 in human sera from persons of blood group A and O shows a changing pattern with increasing age. These results are consistent with the findings for influenza virus and are discussed. Repeated exposure of a population to infection results in obscuring genetically determined variations in susceptibility.

I would like to thank Professor M. G. McEntegart, Professor of Medical Microbiology, and Professor C. H. Stuart-Harris, Professor of Medicine, for their advice and criticism, and Miss D. Coles, F.I.M.L.T., and Mrs P. Robinson for expert technical assistance.

It was possible to demonstrate from retrospective records that a link existed between contaminated animal feedstuffs, turkeys and an outbreak of Salmonella senftenberg infection at Ryhope Hospital. Possibly infected or contaminated turkeys were supplied to the hospital from two turkey farms in one of which the birds were fed on contaminated white fish meal and the other had had infected birds.

This work was carried out months after the events described and would not have been possible without the help and co-operation of the Public Health Laboratory Service, The Veterinary Field, Investigation and Research Services, Houghton Poultry Research Station, The Medical Officer of Health for Brighton, Dr Rosetta Parker, and the various feed companies involved, who very kindly made their records available to us.

Between August 1964 and November 1965 Salmonella senftenberg was isolated from poultry, sheep and cattle on eight farms in England and Scotland. From an analysis of the case records its presence would appear to be incidental; but it may contribute to poultry mortality by acting in conjunction with other intercurrent infections or following stressful events such as severe debeaking or cold brooder conditions.

I should like to thank the officers of the veterinary field investigation and research services who made available their records and notes for this work, and who visited the farms and hatcheries, but especially Mr R. Duff, Veterinary Laboratory, Lasswade, for his reports on the turkey poults from farm A; also Dr Betty Hobbs and Mr B. Hanson for their valuable criticisms.

Experiments have been carried out on the extent to which movement of persons in a room ventilated by a horizontally directed uniform air velocity can transport airborne bacteria from one position to another. More than 107 particles approximately 13 μ in diameter (settling rate in air about 1 ft./min.) carrying spores of Bacillus subtilis var. niger were liberated in each experiment and the numbers reaching the different parts of the room were estimated by those recovered on exposed settling plates. At air velocities of 35 ft./min. and over, no particles could be certainly found to have moved against the direction of air flow except into areas actually entered by persons, and the numbers found in these areas were between 100 and 1000 times less than would have been expected in rooms turbulently ventilated with the same volume of air. There was some transport of particles transversely across the air-flow lines but at 4 ft. distance from the area where movement of persons was taking place the numbers had fallen substantially below 1/100 of those to be expected in a turbulently ventilated room.

The results recorded at an air velocity of 22 ft./min. were significantly less satisfactory.

Our thanks are due to the N.W. Metropolitan Regional Hospital Board, to the Hospital Management Committee of St Charles' Hospital, London, W10, and especially to the hospital engineer for accommodating the experimental room and facilitating its operation.

Some effects of freeze-thawing on the T 4 bacteriophage have been studied. The results indicated that most of the inactivation of rapidly thawed samples was due to osmotic damage, whereas inactivation of slowly thawed samples appeared to be correlated with the eutectic temperature of the suspending medium. Peptone significantly increased the survival of slowly thawed T 4 phage. The particular constituents of peptone largely responsible for this protection were separated as two distinct peptide fractions, using G 25 Sephadex.

This work has been supported in part by grants from the Medical Research Council and the Office of Naval Research under contract F61052–68-C-0041.

Primary kitten kidney cultures are frequently contaminated with wild feline infectious enteritis (FIE) virus and this led the authors to develop feline embryo diploid cell lines. Monolayer cultures were prepared from the lungs or from eviscerated and decapitated carcases of embryos obtained by Caesarian section from healthy pregnant queens. At about the 30th passage, these cells lost their fibroblastic morphology to become polygonal. After a further thirty passages the monolayers exhibited foci of low cell density circumscribed by bands of cells stacked in disorganized arrangement. All the developed cell lines were susceptible to infection with FIE virus and produced intranuclear changes resembling those described by Johnson (1965) in primary kitten kidney monolayers.

On four occasions the cell lines became contaminated with Mycoplasma and although there was evidence that the virus could infect the cells, there was no production of infective virus.

A simple karyotype was devised in which the 38 chromosomes were arranged in three groups according to the arm-length ratio and the percentage mean index length. After the 50th passage many of the nuclei of lung-derived cultures exhibited abnormal chromosomes resulting from ring formation or translocation, whilst those of embryo culture demonstrated a new modal chromosome number of 37.

We are grateful to Mrs L. Hitchcock and Mrs P. Waller, A.I.S.T., for technical assistance, to Mr E. A. Jones, A.I.I.P., for the photomicrographs and to Dr R. H. Johnson, University of Bristol, for supplying the leopard and mink enteritis viruses.

A retrospective survey of Coxiella burnetii infection in North-Western England and North Wales was made in five Public Health Laboratories for the years 1962–6 inclusive. Groups of the normal population and of persons occupationally exposed to infection were tested for the presence of antibody and the incidence of infected milk was investigated in seven counties.

Forty-one cases of C. burnetii infection were diagnosed in 7046 patients investigated serologically for the presence of viral and rickettsial antibodies. In just over a quarter of the patients there was evidence of occupational hazard or a history of drinking raw milk. The remainder gave no relevant history.

We would like to express our thanks to Dr C. M. Patricia Bradstreet of the Standards Laboratory, Colindale, for the supply of antigen, and to the numerous clinicians who allowed us access to their case records.

1. Ninety-seven (83.6%) of 116 reptiles, comprising 70 lizards, 40 snakes, 4 tortoises and 2 crocodiles, yielded isolations of organisms in the Salmonella and/or Arizona groups.

2. The reptiles were captive or free-ranging; the former were drawn from all states of mainland Australia, while the latter were from West Australia only.

3. The relative prominence of Salmonella serotypes containing numerically high somatic antigens, the finding of new serotypes, of multiple infections, and of strains in subgenera II and III was remarked.

4. The lack of evidence of differences in the serotypes isolated from captive or wild reptiles (except for the isolation of S. typhimurium in creatures closely associated with man and his domestic fauna), and the apparent absence of a specific geographical distribution of serotypes in reptiles, lent support to the con clusion that reptiles provide a natural reservoir for Salmonella and Arizona strains in Australia. The possible spill-over to man, his domestic animals and his food stuffs is discussed.

It is a pleasure to record our indebtedness to Dr Joan Taylor for her continuous interest and support in providing confirmation and identification of many Salmonella serotypes; to Dr W. H. Ewing and later Dr R. Rhode for serotyping the Arizona strains; to Dr G. M. Storr, Curator of Reptiles in the Museum of Western Australia, for identifying the reptiles and to Dr W. S. Davidson, Commissioner of Public Health, Western Australia, for permission to publish.

1. An outbreak of ‘Winter Vomiting Disease’ is described involving women at a University Hall of Residence. Of the 165 women exposed, 74 vomited in the first 24 hr., and 17 more over the next 4 days.

2. Public health investigations were negative.

3. On the hypothesis that the vomiting was at least partly hysterical it was predicted that the affected would have higher N scores than the unaffected on the Eysenck Personality Inventory; that they would have a higher frequency of past attendance at the University Health Centre; and that they would be non-randomly distributed through the Hall and its annexes. All these predictions proved to be incorrect.

4. There is some slight but consistent evidence to suggest that there is a neurotic component in the small group of 28 who felt nauseated but did not vomit.

5. The histogram of time of vomiting has two peaks. It is shown that 71 out of the first 74 cases can be accounted for on the hypothesis of contamination of the food at both lunch and dinner on the first day of the outbreak, with the mean response coming 7 hr. after eating.

6. It is suggested that these results make a food-borne agent a more likely explanation of ‘Winter Vomiting Disease’ than the currently favoured airborne virus acting via the central nervous system.

The costs involved in the psychiatric side of this investigation were defrayed by a grant from the Clinical Research Committee of the Middlesex Hospital. We would like to thank the Chairman and members of the Committee for making these funds available and for their interest and confidence. We would also like to thank Dr A. W. Beard, Consultant Physician at the Middlesex Hospital for his advice and support.

A variety of factors that affect lecithinase activity and lecithinase production by Cl. welchii were studied. The lecithinase activity was time and temperature dependent. The optimum temperature varied from 30° to 46° C. according to the strain of Cl. welchii employed. Maximum lecithinase activity was produced after 12–60 hr. There was considerable strain variation. This could easily account for the differences in the published data.

Commercial purified lecithinase was more readily destroyed by heat than the lecithinase produced by Cl. welchii in culture media. The enzyme inactivation pattern at 60° C. was similar to that at 90° C. This is not in agreement with the reports of others who found that less enzyme was inactivated at the higher temperatures.

Acid pH values completely inactivated the enzyme. However, alkaline pH values did not significantly destroy the enzyme. The lecithovitellin reaction was completely inhibited at pH values of 1–5. The optimum pH for the reaction was around pH 7–8.

The production of lecithinase was dependent upon the pH of the culture medium. One strain produced measurable lecithinase at pH values of 5·5–8·5, whereas another strain produced lecithinase only at pH values 6–5–7–5.

Lecithin stimulated the production of lecithinase in a chemically defined medium.

The lecithinase and haemolytic activity of thirty strains of Cl. welchii isolated from food, faeces, and soil, was studied. The strains from foods produced smaller amounts of lecithinase and were, in general, less haemolytic than the strains isolated from soil and faeces.

The haemolytic activity of Cl. welchii on erythrocytes from different animal species displayed considerable variation. Sheep erythrocytes were the most sensitive to the action of alpha toxin, whereas rabbit blood was most sensitive to haemolysis by theta toxin. The degree of haemolysis was also dependent upon the concentration of the enzyme, and temperature and length of incubation.

The haemolytic activity of commercial lecithinase was observed to be similar to the haemolytic activity of the alpha toxin of Cl. welchii. This finding provides further evidence that the haemolytic and lecithinase activities of Cl. welchii are due to one substance, the alpha toxin. Exposure of commercial lecithinase to heat resulted in the destruction of its haemolytic properties.