bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors affecting the growth of virus of foot-and-mouth disease on surviving explants of bovine tongue epithelium
Authors: Morrow A. W , Buckley L. S
Published: May 2009

A simple, laboratory scale, stirred system has been developed to examine conditions of culture necessary for optimum return of infective virus from explants of surviving bovine tongue epithelium, with particular bias towards large-scale procedures.

Control of hydrogen-ion concentration and aeration of the culture are emphasized.

The authors wish to thank Dr I. A. Galloway and Dr J. B. Brooksby for their helpful advice in preparing this paper, Mrs J. Lansley for her untiring technical assistance and Mr J. Goodridge who constructed the culture apparatus.
The site of specific substances in capsulated organisms
Authors: Barber Cella
Published: May 2009

Applying a method of selective separation of the specific high polymers the intracellular site of the specific substance in the Copenhagen strain of Pneumococcus Type II was demonstrated, by electron microscopy; the specific polymeric material assumed to form the capsule is situated within the bacterial cell and the electron density of this material is sufficiently high to permit its detection.

The possibility of obtaining electron micrographs of the polymeric substances as contained in the cells or after their diffusion into the medium or when secreted as slime, suggests that the current concept of the capsules as the site of the specific substances may have to be reviewed.

The electron micrographs were made by Dr A. Petrovici to whom I express my thanks.
Physical and serological investigation of Rift Valley fever antigens
Authors: Levitt Julia , Polson A.
Published: May 2009

1. Extracts containing non-infective soluble antigens have been prepared from the tissues of mice infected with a pantropic or any of three neurotropic strains of Rift Valley fever virus. The antigens were detectable by complement-fixation and gel-precipitin tests using antisera prepared in mice.

2. The extracts appeared to contain at least two antigens separable by electrophoresis and distinguishable by Ouchterlony tests. The faster migrating minor antigen occurs sparsely and was not further examined.

3. No distinction, physical or immunological, was observed between the major antigen derived from the four strains.

4. In gel diffusion-filtration experiments with granulated 7 % agarose, the major antigen appeared to be polydisperse containing particles with diffusion rates ranging from at least as low as that ofBurnupena cinctahaemocyanin to almost as high as that of haemoglobin.

5. Centrifugal analysis indicated the presence of particles having sedimentation constants of about 8, 29 and greater than 100 Svedberg units. These particles have a density of about 1·27 g./ml. If all the particles of the major antigen are spherical, with a density of 1·27 g./ml., the three size groups have diameters of about 7–8, 14 and < 26 mμ.

6. The diffusion coefficient of the smallest particle was estimated to be 6·06x 10−7cm.2/sec. corresponding to a sphere 7 mμ in diameter, or 4·78 x 10−7cm.2/ corresponding to a sphere 9 mμ in diameter depending on which of two values for the diffusion coefficient of mouse γ-globulin is used in the calculation.

7. In density gradient zone electrophoresis at pH 8·6, the principal antigen migrated at about the same rate as haemoglobin and appreciably slower than the virus. The authors are indebted to Prof. A. Kipps for his continued interest in this work, and to Dr T. H. Mead for valuable criticism of this paper. This investigation was supported in part by a Public Health Service research grant Al 04044–02 from the National Institute of Health, Bethesda, U.S.A.
Survival of shigellae in food
Authors: Taylor Barbara C. , Nakamura Mitsuru
Published: May 2009

The survival and persistence ofShigella sonneiandS. flexneriin various food preparations were studied. The length of survival and the rate of decrease in surviving fractions varied considerably depending upon the menstruum and the holding temperature. This study points out the potential hazards involved in consuming food products that may be contaminated by shigellae.
Simultaneous active and passive immunization of guinea-pigs against tetanus
Authors: Smith J. W. G.
Published: May 2009

1. Simultaneous active and passive immunization of guinea-pigs using tetanus toxoid adsorbed on to aluminium hydroxide produced a higher antitoxin response than simultaneous immunization using plain toxoid. The response was also better than that produced by plain toxoid alone.

2. A 24 hr. interval between the injection of plain toxoid and the subsequent injection of antitoxin gave no better results than when toxoid and antitoxin were given at the same time.

3. The response to simultaneous immunization, using adsorbed toxoid, of guinea-pigs sensitized to horse serum, was superior in the first 6 weeks to that of guinea-pigs which had not been sensitized.

4. The suggestion that simultaneous active and passive immunization of man should be performed with adsorbed toxoid rather than plain toxoid is supported by these results.
A complement fixation technique for the quantitative measurement of antigenic differences between strains of the virus of foot-and-mouth disease
Authors: Davie John
Published: May 2009

1. A complement fixation test has been developed to measure the minor antigenic differences which occur between strains of the virus of foot-and-mouth disease of the same immunological type.

2. Strain-specific sera were prepared from each of the virus strains examined and then titrated with each of the antigens.

3. The amounts of complement fixed in each reaction were measured in the region of maximal fixation where the antigen and antibody were present in optimal proportions.

4. Heterologous antigen-antibody reactions were compared with the homologous reaction in each test and expressed as cross-fixation ratios.

5. Pairs of antigens could then be compared by taking the product of their cross-fixation ratios one with the other. The values of cross-fixation product so obtained ranged from 1·0 between identical strains to 0·01 between strains of different immunological type.

6. Strains of virus which exhibit cross-fixation products of 0·5 or more with one another have been classified within subtype groups.

I wish to acknowledge the guidance and encouragement of Dr J. B. Brooksby, Director of the Animal Virus Research Institute, Pirbright, and the technical assistance of Mr E. Scoates.
The development of skin resistance and hypersensitivity following inactivated vaccinia virus vaccines in rabbits
Authors: McNeill T. A.
Published: May 2009

A study was made of the development of skin resistance and delayed hyper-sensitivity to vaccinia virus after immunization with inactivated vaccinia virus in rabbits. These vaccines are shown to increase skin resistance, and it is also shown that the development of this resistance is dependent upon the virus content of the vaccine. Skin resistance is shown to be related to the titre of circulating antibody rather than to the degree of delayed hypersensitivity. Possible reasons for conflicting reports in the literature on this subject are discussed.

An unusual skin reaction was seen in some animals when challenged with live virus after immunization with inactivated vaccine. The nature of these reactions is discussed.
Prevalence of toxoplasma antibodies in sera from Greece and Africa
Authors: Fulton J. D. , Fleck D. G. , Payne R. A.
Published: May 2009

Sera from healthy Greeks, Liberians and East Africans were tested for dye test and direct agglutinating toxoplasma antibodies. At a titre of 1/16 or more 137/228 Greeks, 84/133 Liberians, 2/13 Bondei infants, 3/7 Bondei adults, 3/9 Masai infants and 20/43 Baganda adults gave a dye test positive result. This confirms the wide-spread occurrence of this infection.
Streptococcal infection in young pigs. II. Epidemiology and experimental production of the disease
Authors: Elliott S. D. , Alexander T. J. L. , Thomas J. H.
Published: May 2009

1. In streptococcal infection of piglets the causative agent (PM streptococcus) was isolated from the throats of a high proportion of infected animals and from their apparently healthy litter-mates.

2. The PM streptococcus was isolated from the noses of three out of forty-three normal sows. In one sow the streptococcus was also isolated from the throat.

3. Bacteriaemia was induced in piglets up to the age of 17 days by inoculating into the nose and throat broth cultures of the PM streptococcus. Blood cultures were usually positive within 24 hr., and secondary involvement of the joints and meninges frequently occurred during the ensuing few days.

4. Serum taken from piglets 5 weeks after experimental infection and administered subcutaneously protected susceptible piglets against subsequent infection with PM streptococci.

5. The possibility of preventing streptococcal infection in piglets by active immunization of the sow is discussed.
Further studies with quadruple vaccine
Authors: Dane David S. , Haire Margaret , Dick George , Briggs E. Moya , Connor T. J.
Published: May 2009

Reactions to the pertussis component of the original commercial batches of quadruple vaccine against poliomyelitis, diphtheria, tetanus and pertussis (Quadrilin, Glaxo Laboratories) gave some cause for concern. Severe reactions were found to be more common in infants under 6 months of age than in older infants.

A modified quadruple vaccine, which has been used in N. Ireland since October 1964, was found to give rise to significantly fewer and milder reactions. This vaccine when given in three doses separated by intervals of 6–9 weeks and 6 months to fifty-eight infants most of whom were 6–7 months of age at the start of immunization was found to give a satisfactory immunological response.
Immunogenicity of experimental trachoma vaccines in baboons: I. Experimental methods, and preliminary tests with vaccines prepared in chick embryos and in HeLa cells
Authors: Collier L. H. , Blyth W. A.
Published: May 2009

Parallel titrations of a strain of trachoma (MRC–221) and one of inclusion conjunctivitis (MRC–4) in the baboon conjunctiva and in chick embryos suggest that ten to twenty 50% egg infective doses are equivalent to one 50% baboon infective dose; but that at least 1000 egg infective doses are needed to induce moderate or severe infections in all of a given number of baboons.

For vaccine experiments in baboons, a system of scoring physical signs and presence of inclusion bodies was devised; the significance of differences in vaccinated and control animals in their response to conjunctival challenge was determined by analysis of variance. An aqueous suspension of live MRC–4 grown in the yolk sac was given as two subcutaneous doses and one intravenous dose at weekly intervals, and protected all of six baboons challenged with the homologous strain; three similarly spaced subcutaneous doses were less effective. The immunity induced by this vaccine waned considerably during the ensuing 15 months. Vaccine prepared from a live ‘fast-killing’ variant of MRC–4 grown in HeLa cells was less effective than MRC–4 itself in protecting baboons against infection with the parent strain.

Although both yolk sac and HeLa cell vaccines induced the formation of antibody fixing complement with trachoma group antigen, the serum titres in individual animals at the time of challenge were unrelated to the degree of protection; during a 15 month observation period there were pronounced falls in the titres of antibody induced either by vaccination or by challenge with egg-grown TRIC agent.

We wish to thank Dr I. Sutherland (M.R.C. Statistical Research Unit) for his helpful advice during the early stages of this work. We are also greatly indebted to Mr P. Avis (Pfizer Ltd.) for his advice and for undertaking the statistical computations; and to Miss Anne Smith and Miss Pay Storey (M.R.C. Trachoma Research Unit) for doing the complement fixation tests.
The inhibition of growth of vaccinia and cowpox viruses in RK 13 cells
Authors: Baxby Derrick , Rondle C. J. M.
Published: May 2009

The growth of vaccinia and cowpox in RK13 cells was studied by measurement of infective virus production, gel diffusion and haemagglutination. The effects of virus growth inhibitors on the normal course of infection were then followed. Although the results with the two viruses were essentially similar some differences were detected between them. Inhibitors of DNA synthesis permitted production of many virus-specific soluble antigens. Compounds which inhibit DNA function and compounds that affected energy-yielding reactions had more dramatic effects. The different results obtained suggested that the synthesis of virus-specific materials was sequential and a possible part of the sequence is suggested.
Age susceptibility and excretion ofSalmonella typhimuriumin calves
Authors: Robinson R. A. , Loken K. I.
Published: May 2009

Two groups of calves were dosed orally with 104, 105, and 106S. typhimuriumat approximately 2 days of age and at 14–21 days of age. No obvious clinical signs were observed with this strain, but younger calves excreted the salmonellas in the faeces for longer periods than older animals. The younger animals also excreted more salmonellas per gram of faeces in the first week following dosing. These observations may explain why salmonella cross-infection is likely to occur where very young calves are congregated. Following cessation of excretion of salmonellas in the faeces and subsequent slaughter of calves, examination of all the mesenteric, caecal, and colic lymph nodes showed these to be the most useful sites for recovery of salmonellas.

Provided good nutrition and hygienic conditions prevail, calves retained on their farm of origin for longer periods are more likely to recover from neonatal salmonella infections.
Evidence for a two-stage model of microbial infection
Authors: Meynell G. G. , Maw Joan
Published: May 2009

Colony counts on mice given the same number ofSalmonellaalways differ considerably. However, the standard error of the mean log count does not increase after the first 1·5 hr. of infection until the 8th or 10th day. These infections therefore appear to pass through an initial stage lasting a few hours, in which a varying proportion of the inoculum is killed, followed by a prolonged second stage in which the scatter in individual colony counts remains constant.
Inhibition by pyrimidine analogues of the synthesis of folic acid by trachoma agents
Authors: Reeve P. , Taverne Janice , Bushby S. R. M.
Published: May 2009

Trimethoprim, a 2,4-diaminopyrimidine derivative which inhibits the growth of some bacteria by interfering with folic acid synthesis, inhibited the growth of several strains of the trachoma agent. Inhibition was most clearly demonstrated by measuring prolongation of mean death time of groups of chick embryos inoculated with a single lethal dose of agent. Over a certain range, prolongation was proportional to the logarithm of concentration of inhibitor; higher concentrations were toxic for the embryo. On a weight basis, trimethoprim was not as active as sulphafurazole. Inoculation in conjunction with sulphafurazole resulted in slight potentiation of activity. A related pyrimidine derivative, the antimalarial drug pyrimethamine, also significantly inhibited the growth of one strain of trachoma.

In cell culture, trimethoprim decreased the number of inclusions formed by a suspension of the trachoma agent and induced morphological changes in the inclusions similar to those caused by sulphafurazole.

Inhibition of the growth of the trachoma agent in the chick embryo was reversed by leucovorin calcium. It is concluded that, as with bacteria, the drug acts by blocking the folio acid cycle and that the trachoma agent most probably contains a dihydrofolate reductase.
Bacteria in a hospital nursery: laboratory and clinical studies
Authors: Winton F. W. , Keay A. J.
Published: May 2009

Two hundred and twenty-two infants and fifty-one staff were examined for carriage ofStaphylococcus pyogenesand Gram-negative bacilli, and the presence of these bacteria in the ward environment was also investigated. Staphylococci were phage-typed and tested for sensitivity to antibiotics. Assessment of clinical infection caused by these bacteria was made.

Infant carriage ofStaphylococcus pyogeneswas maximal on the sixth day, 73·1 % of umbilical swabs yielding significant growth. Carriage of Gram-negative bacilli was maximal on the fifth day, 31·7% of umbilical swabs being positive. Where special nursing was enforced, i.e. premature baby unit, isolation of Gram-negative bacilli was very infrequent.

The low nasal carriage of staphylococci seen in infants and nursing staff is attributed to traces of penicillinase-resistant penicillins in the ward air.

Staphylococcus pyogeneswas recovered from 23 % of ward surfaces, and constituted 0·7% of the air-borne flora. In contrast, Gram-negative bacilli were recovered from 4·7 % of surfaces, and composed only 0·15% of the air-borne flora.

Phage group I constituted 73·0, 44·9 and 41·2% of strains from infants, staff and ward environment respectively.

Antibiograms were grouped into three categories, A, B and C. Category A (sensitive to chloramphenicol, erythromycin and methicillin but penicillin-resistant) composed 79·0% of infants' strains, being found mostly in group I, but was rare among staff strains.

Of 54 specimens taken from 40 infants showing evidence of infection,Staphylococcus pyogeneswas isolated from 16, of which 14 were category A. Gram-negative bacilli were isolated 7 times. Only 21 infants required antibiotic therapy (9·3%) and none were infected with Gram-negative bacilli—this contrasts with the frequency of these bacilli in nursery infection today.

Ward air is considered to be the maindepotofStaphylococcus pyogenes. Infant ‘dispersers’ are probably the principalsourceof the air-borne staphylococci. Infants and staff abstract from the air those staphylococci which become their colonizing strains. No transfer is thought to occur from the staff to the infants. Transmission of Gram-negative bacilli is similar in that the infants are the principal source and the air the maindepotof these bacteria. Nasal colonization by Gram-negative bacilli is low, this is possibly due to poor colonizing properties. Infant umbilical carriage almost certainly results from endogenous faecal spread.

We are grateful to Dr J. C. Gould, Director, Central Microbiological Laboratories, Edinburgh, for his continued interest and advice, and to Mr J. C. Ferguson and Mrs M. M. Winton for skilled technical assistance. This study would not have been completed without the co-operation of Sisters McCartney and Struthers and their nursing staff.
Langat virus encephalitis in mice I. The effect of the administration of specific antiserum
Authors: Webb H. E. , Wight D. G. D. , Platt G. S. , Smith C. E. G.
Published: May 2009

1. When mice are infected intraperitoneally with Langat virus only a small proportion develop clinical encephalitis, but all mice have substantial titres of virus in the brain and also incontrovertible histological evidence of encephalitis.

2. When specific antibody is given intraperitoneally or intravenously to mice during the first 3 days after intraperitoneal infection with Langat virus, the viraemia (normally maximal during this period) is depressed, the production of antibody is depressed or delayed, and the incidence of clinical encephalomyelitis is increased significantly.

3. Specific antibody given intraperitoneally or intracerebrally before infection, protects the animals from encephalitis.

4. These findings are discussed in terms of the histology of the central nervous system of the affected mice.

We are very grateful to Miss S. J. Illavia, B.Sc., and to Miss G. E. Fairbairn for their skilled technical assistance; and to Mr S. Peto of the Microbiological Research Establishment for statistical advice.

This work was made possible by a generous grant from the Wellcome Trust and the Endowment Funds of St Thomas's Hospital
Elevated temperature incubation of enrichment media for the isolation of salmonellas from heavily contaminated materials
Authors: Harvey R. W. S. , Price T. H.
Published: May 2009

In three separate series, samples were examined for salmonellas by culture in selenite F broths incubated at 37 and 43° C. The samples used were:

(1) Gauze swabs placed in sewage.

(2) Gauze swabs placed in drains in abattoirs.

(3) Sewage-polluted river water.

In each series the higher temperature gave better results.

The modification of tetrathionate broth for incubation at 43° C. and the adjustment of the incubation temperature to suit more inhibitory enrichment broths is discussed. The medium of Rappaport, Konforti & Navon (1956) is not suited to incubation at 43° C.

We should like to acknowledge the help of Prof. Scott Thomson in the preparation of this paper, and the capable technical assistance of Mr T. R. Liddington and Mr John Morgan. We are also indebted to Dr H. Campbell, Senior Lecturer in Medical Statistics in the Welsh National School of Medicine, for his advice and to Mr M. C. Finniear, Deputy Public Analyst of the Glamorgan County Public Health Laboratory, for the calculation of molar tetrathionate in Rolfe's tetrathionate broth.
The epidemiology of respiratory infection in an isolated Antarctic community
Authors: Cameron A. S. , Moore B. W.
Published: May 2009

The results of a combined clinical and laboratory study of respiratory infections among members of an Australian Antarctic expedition are presented. Virus isolation and serological methods were employed, but the aetiological agent or agents responsible for respiratory infections in this group were not revealed.

The clinical findings were correlated with published and unpublished studies on comparable communities, and the following broad pattern of the epidemiology of respiratory tract infections in such groups has emerged. The assembly on board ship of a party from widely separated areas often leads to infections after embarkation. On long voyages these infections may burn out, but frequently new cases are still appearing when the party arrives in Antarctica. Symptoms in sufferers at this time become more severe, suggesting that the sudden environmental change from the warmth of an air-conditioned ship to the harsher Antarctic conditions may influence the course of the respiratory infections. With isolation established in Antarctica, further cases rarely appear. On exposure to the relief party, however, infections can be expected, and it is noted that morbidity is usually low and symptoms are mild, indicating an apparent heightened resistance to infection in the acclimatized party while still on the ice.

This study has further shown that most of these men, on returning to urban societies, contracted moderately severe upper respiratory tract infections in contrast to their apparent resistance when under Antarctic conditions.

The suitability of these groups for experimental study, including the inoculation of volunteers, was discussed and suggestions were made for future work.
A new approach to development of live vaccine against tick-borne encephalitis
Authors: Smorodintsev A. A. , Dubov A. V. , Ilyenko V. I. , Platonov V. G.
Published: May 2009

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.
Protection from microbial contamination in a room ventilated by a uni-directional air flow
Authors: Lidwell O. M. , Towers A. G.
Published: May 2009

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.
Frequency of rubella antibodies among adult population in Greece
Authors: Papaevangelou George J.
Published: May 2009

No significant sex difference in the incidence of immunity to rubella at the ages of 20–25 was found in a comparative study of young adults from the Greater Athens area as well as from the rural department of Corinthia. The immunity to rubella of Greek adults on a national scale was then studied in a respresentative sample of 1200 males 20–25 years old. In 83·2% of them neutralizing antibodies to rubella were detected. A statistically higher proportion of immunes was found among those from urban areas. The factors responsible for the relative prevalence of immunity to rubella in various population groups are discussed.
A selective motility medium for routine isolation ofSalmonella
Authors: Harper J. , Shortridge K. F.
Published: May 2009

A modified Shigella—Salmonella medium in semi-solid agar was shown to inhibit the spread of most faecal organisms through a Craigie tube, while selectively allowing the passage ofSalmonella.

A medium for routine use is described.

Over a period of 3 years, in this laboratory, 90% of specimens from which salmonellas were isolated gave positive results with this medium. Over 40% of these specimens would have been reported as negative if the method had not been in use. However, 10% would have been missed if this method alone had been used. It should therefore be used in conjunction with other culture methods, of which direct plating on SS agar was the most successful in this series.
Antibody against influenza A2 virus neuraminidase in human sera
Authors: Schild G. C. , Newman R. W.
Published: May 2009

1. High titres of neuraminidase-inhibiting antibody were detected in convalescent human sera following natural influenza A2 infections.

2. Such antibody was encountered infrequently in acute serum samples. Antibody persisted only 5–6 months after infection in the four individuals from whom serial serum specimens were available.

3. Following immunization with killed influenza virus vaccines (with adjuvant) neuraminidase inhibiting antibody was detected in human sera. The titres were in general lower than those detected in convalescent human sera.

4. The specificity of the neuraminidase-inhibiting antibody in human and animal antisera was studied. Tests with convalescent human sera using purified neuraminidase preparations and with a recombinant virus containing A2 neuraminidase and haemagglutinin distinct from that of human influenza A viruses enabled the conclusion that the antibody detected was specific for influenza A 2 neuraminidase.

We wish to thank Dr D. A. J. Tyrrell of the Clinical Research Centre, Mill Hill, London, for human serum specimens, Dr D. Breeze of Evans Medical Ltd., Liverpool, for sera from an influenza vaccine trial and Dr M. S. Pereira of the Public Health Laboratory, Colindale, London, for serial serum samples from persons who had influenza in 1957. Dr M. S. Pereira carried out the haemagglutination-inhibition tests and complement fixation tests on these sera.

We are grateful to Dr H. G. Pereira and Dr D. A. J. Tyrrell for valuable discussions during the course of this study, and to Professor C. H. Stuart-Harris for his comments on the manuscript.
Quantitative aspects ofMycoplasma pneumoniae-cell relationships in cultures of lung diploid fibroblasts
Authors: Larin N. M. , Saxby N. V. , Buggey D.
Published: May 2009

The FH strain ofMycoplasma pneumoniaewas studied in experimentally infected cultures of lung diploid fibroblasts. The multiplicity of infection was found to have a profound influence on the distribution of the cell-associated and extra-cellular mycoplasmas. At a high multiplicity there was very little difference between the ratio of cell-associated and extracellular mycoplasmas. In contrast, with a low multiplicity the cell-associated mycoplasmas predominated and with further reductions of the inoculum only the cell-associated mycoplasmas could be detected. The significance of these findings is discussed. It is suggested that caution has to be exercised in the determination of the potency of antibiotics against mycoplasma by methods employing acellular media alone, and it is desirable to utilize also appropriate cell culture models. A possible approach to designing such models is provided by this study.

We express our appreciation to the Tissue Culture Laboratory, Pfizer Limited, Sandwich, for kindly supplying us with cell cultures. We furthermore thank the Board of Directors, Pfizer Limited, for permission to publish this study. The helpful discussions with our colleagues Drs D. Jackson and G. M. Williamson in preparing the manuscript are acknowledged with thanks.
Bacterial contamination on the surface of hospital linen chutes
Authors: Whyte W. , Baird G. , Annand R.
Published: May 2009

A survey of 13 linen chutes in eight hospitals was carried out to assess the amount of bacterial contamination on the inner walls of these chutes. It was shown that the average bacterial count in these chutes was low by general hospital standards (19·7 bacterial colonies per Rodac plate). This concentration was eight times less than the average concentration found on the floor surface at each linen disposal and collection point (153 bacterial colonies per Rodac plate).

Three chutes sampled during the survey were periodically cleaned but appeared to derive only very limited benefits from the cleaning method they used.

Tests carried out on three linen chutes showed that the bacterial surface contamination of a sterilized chute could normally reach a maximum concentration in a period of between 4 and 24 hr.

It is concluded that so long as good engineering practices are used in the construction of linen chutes the bacterial contamination on their inner surface should not contribute to the problem of hospital cross infection. For this reason, and because of the impracticability of sterilizing linen chutes at very short intervals of time, it is considered that cleaning of chutes would serve no practical purpose.

Thanks must be recorded to the authorities of all those hospitals who gave their permission for us to study their linen disposal chutes and afforded us every assistance.

We should also like to thank Mr W. Carson, Leader of the Building Services Research Unit, for his help and encouragement.

The work reported was a part of an investigation into the design of linen disposal chutes sponsored by the Western Regional Hospital Board, Scotland.
Haemorrhagic smallpox
Authors: Downie A. W. , Fedson D. S. , Vincent L. St , Rao A. R. , Kempe C. H.
Published: May 2009

In practically all acute fulminating smallpox infections—haemorrhagic type I cases—there is severe viraemia with 104 or more infective particles of virus per ml. of blood. In most of these patients soluble antigen can be demonstrated in serum by precipitation in agar gel tests, or by the complement-fixation technique. In late haemorrhagic cases (type II) the degree of viraemia is less and soluble antigen is less often demonstrated in the blood. Five of forty type II patients recovered. The majority of the 77 patients studied were adults and bore scars of previous vaccination. Thirteen were pregnant women and 10 of these suffered from type I infections.

The antibody response in patients who survived 6 days or longer as determined by the estimation of precipitins, CF antibodies and neutralizing antibodies in serum, was considerably less than that seen in non-haemorrhagic smallpox patients.

In acute fulminating smallpox infections, the finding of virus or soluble antigen in the blood is of value in establishing the diagnosis. Soluble antigen is usually found in the blood of patients suffering from severe viraemia and with the methods used has been demonstrated only in patients who are to die of their disease. Haemorrhagic smallpox represents a generalized virus infection of unusual severity in patients who show little resistance to their infection. The cause of this unusual susceptibility is unknown but there is little evidence that specific allergy to the virus is a feature of this form of the disease.

This investigation was supported in part by Public Health Service Grant AI–1632–16 VR from the National Institute of Allergy and Infectious Diseases, by the World Health Organization and by the Marcus T. Reynolds III Fund.
Conjunctivitis and subclinical infection in smallpox
Authors: Kempe C. H. , Dekking F. , Vincent L. St , Rao A. R. , Downie A. W.
Published: May 2009

Attempts were made to demonstrate variola virus in the conjunctival exudate of 84 smallpox patients who developed conjunctivitis in the acute stage of the illness or during convalescence. Variola virus was isolated from 60 but not from the remaining 24. Of the 64 from whom virus was isolated the conjunctivitis developed from the onset up to the 15th day of illness. From conjunctivitis developing later virus was not recovered. In some patients who developed conjunctivitis early in the disease we failed to recover virus from the conjunctival exudate.

Of 55 close family contacts who stayed in hospital with smallpox patients four developed smallpox. In 21, conjunctivitis but no other illness developed. From 12 of these, variola virus was recovered from the conjunctival exudate and four of these 12, who were further investigated, showed after the appearance of conjunctivitis antibody titres similar to those seen in typical smallpox cases. From nine of the contacts who developed conjunctivitis virus was not recovered. One of these had antibody titres in serum collected before the onset of conjunctivitis which indicated recent smallpox infection. In another there was a marked antibody rise during her hospital stay although examination of conjunctival exudate on three separate occasions failed to yield variola virus. Twenty-six family contacts who developed no illness in hospital had antibody determinations made on sera collected soon after admission to hospital. In eight of these antibody titres were such as to indicate recent smallpox infection although there were no signs, in the form of scarring, or history of recent smallpox infection. These findings have been discussed in relation to the occurrence of minimal and subclinical infection in close family contacts of smallpox patients.

This investigation was supported in part by Public Health Service Grant AI–1632–16 VR from the National Institute of Allergy and Infectious Diseases, by the World Health Organization and by the Marcus T. Reynolds III Fund.
A survey of infectious mononucleosis in the North-East Regional Hospital Board area of Scotland, 1960–9
Authors: Davidson R. J. L.
Published: May 2009

This report, based largely on 1258 laboratory proven cases of infectious mononucleosis (IM) detected in the North-Eastern Regional Board area of Scotland during the years 1960–9 inclusive, describes and discusses some of the epidemio-logical and diagnostic aspects of the disease.

During the period of study, the annual rate of incidence increased fourfold from 11·1 to 44·3 cases per 100,000 population. Evidence is presented to indicate that this does not represent a true increase in prevalence but reflects improvements in disease detection. The annual incidence rates as reported by the C.D.S. for 1967–9 inclusive are regarded as a considerable underestimation of the ‘true’ incidence of the disease. Over a 3-year period an annual incidence equivalent to 100 per 100,000 population was found in each of two selected group practices. This value was constant and is thought to approximate the ‘ true’ incidence of symptomatic, seropositive IM in the general community.

Of the 1258 seropositive cases, 48·7 % were males and 51·3 % females. The peak age incidence was 15–19 years for both sexes. Twenty-one per cent of the cases were in children under 15 years and only 8·1 % in adults older than 25 years. No significant variation was found in the seasonal or urban/rural incidence. Marked differences were found in the leucocyte patterns of seropositive and ‘seronegative’ cases.
Serological studies with human papova (wart) virus
Authors: Ogilvie Marie M.
Published: May 2009

Methods for demonstrating antibody to wart virus by complement fixation and passive haemagglutination tests are described and compared with the precipitin test of Almeida & Goffe (1965). The results reveal the much greater sensitivity of the passive haemagglutination method, particularly in the detection of the immunoglobulin M class of antibody. Both complement-fixing and precipitating antibody were detected in sera from patients whose warts had undergone a spontaneous resolution.

The presence of antibody to wart virus was demonstrated in sera from persons who had had warts up to 10 years previously, and in a few cases from those who thought they had never had warts.

The antigenic identity of virus from hand warts and plantar warts of the simple and mosaic types was revealed, and some evidence was obtained for similar identity of the virus from genital warts.
The natural history of molluscum contagiosum in Fijian children
Authors: Hawley T. G.
Published: May 2009

A 10-month follow-up of 14 Fijian children suffering from molluscum contagiosum showed that the condition could last from about 6 months to about 3 years, but that any one lesion was present for only 2 months. There could be temporary relief from new lesions for at least 2 months; when complete remission occurred, it could be comparatively rapid. It is suggested that individual lesions should not be treated, in order to avoid scarring and because of their relatively rapid disappearance.
Salmonellosis in general practice. Observations of cases and their households in Enfield
Authors: Thomas Mair E. M. , Mogford Hilary E.
Published: May 2009

Nine hundred and seventeen Salmonella infections in 580 households were confirmed during a laboratory study of diarrhoea in general practices in a large urban area during the years 1953–68. This was an annual incidence of about 2/10,000 population. Salmonellas were found in nearly 2% of new cases of diarrhoea investigated. Plural infections were found in 36% of the households studied and 18% of all contacts examined were shown to be infected. Among these contacts the infection rate was higher for children (24%) than for adults (16%). The duration of infection was longer than 2 months in nearly a quarter of the cases followed up, and intermittent excretion was observed in one-fifth. The commonest serotype was Salmonella typhimurium, but its incidence in the district declined especially after 1964. S. typhimurium infection provoked a severer enteritis but less general symptoms than did other salmonellas. Children were more susceptible than adults to salmonella infection, to illness and to prolonged excretion, but symptoms in index cases were as severe in adults as in children.
Clearance of antibiotics from the intestines after termination of antibiotic decontamination
Authors: van der Waaij D. , Lekkerkerk-van der Wees J. E. C. , Heidt P. J.
Published: May 2009

The clearance of neomycin and kanamycin from the intestines after stopping oral supply has been determined in mice. Both antibiotics, although given in different doses, were excreted in essentially the same way; the clearance being a little faster than logarithmically in both cases. The importance of this observation with regard to isolation and the moment of reconventionalization is discussed.
The survival and growth ofBacillus cereusin boiled and fried rice in relation to outbreaks of food poisoning
Authors: Gilbert R. J. , Stringer M. F. , Peace T. C.
Published: May 2009

A number of outbreaks of food poisoning attributed toBacillus cereushave been reported recently and all have been associated with cooked rice usually from Chinese restaurants and ‘take-away’ shops.

Tests were made to assess the heat resistance ofB. cereusspores in aqueous suspension, the growth of the organism in boiled rice stored at temperatures in the range 4–55° C., and the effect of cooking and storage on the growth of the organism in boiled and fried rice. The spores ofB. cereussurvived cooking and were capable of germination and outgrowth. The optimum temperature for growth in boiled rice was between 30° and 37° C. and growth also occurred during storage at 15° and 43° C.

To prevent further outbreaks it is suggested that rice should be boiled in smaller quantities on several occasions during the day, thereby reducing the storage time before frying. After boiling the rice should either be kept hot (> 63° C.) or cooled quickly and transferred to a refrigerator within 2 hr. of cooking. Boiled or fried rice must not be stored under warm conditions especially in the range 15–50° C.
Epidemic vomiting
Authors: Smith H. C. T.
Published: May 2009

Two outbreaks of epidemic vomiting are described. One affected 107 students and staff at a college of education out of a total of 398 persons. The other affected 172 pupils and staff out of 357 at a secondary school. Evidence is presented that in both cases infection was acquired in the dining hall of the institution concerned but no specific item of food was found as a likely cause. The literature is reviewed. Possible mechanisms of spread are suggested.
The Action of Dysentery Bacilli on Nitrites and Nitrates
Authors: Logie W. J.
Published: May 2009

(1) Dysentery strains from various sources have been examined with respect to their power of reducing nitrates to nitrites and of further destroying nitrites. All the strains with one exception (B. Neisser Ac.) reduced nitrates to nitrites. None of the strains which fail to ferment mannite (Shiga type) destroyed nitrites. Those dysentery strains which form acid from mannite differ amongst themselves in regard to their action on sugars and also in their effect on nitrites. Of the eight mannite-fermenting strains examined, two (B. dysenteriae Jürgens and B. Neisser Nc.) failed to destroy nitrites.

(2) B. dysenteriae Jürgens, although closely related to B. dysenteriae Flexner, differs from it both in its action on litmus-whey and in failing to destroy nitrite. It must therefore be considered a different strain. B. dysenteriae Jürgens is remarkable as being the only one of the strains examined which forms indol and at the same time fails to destory nitrites. It is consequently the only one which gives the cholera-red reaction.

(3) The addition of glucose (i.e. of a carbohydrate from which acid can be formed) enables Shiga strains to destroy nitrite.

(4) In the presence of an abundant supply of oxygen all the strains fail to destroy nitrites and nitrates.

(5) In glucose-containing media the inhibitory effect of oxygen is less marked.

(6) Under anaerobic conditions Shiga strains and B. dysenteriae Jiirgens still fail to destroy nitrites.
Report on Experiments Undertaken to Discover whether the Common Domesticated Animals of Terceira Island are Affected by Plague
Authors: De Souza Antonio , Arruda Jacintho , Pinto Manuel
Published: May 2009

We have recently had the opportunity of studying a plague epidemic that broke out on Terceira Island, Azores, in 1908. Terceira Island contains a population of 45,000 souls, the epidemic spread over 27 parishes. About 260 persons were attacked, with a mortality of about 48%.
Typhoid Fever and Mussel Pollution
Authors: Buchan George F.
Published: May 2009

(1) 855 primary cases of typhoid fever in households in Birmingham were investigated.

(2) In 124 or 14·5% of these cases a history of mussel eating within four weeks of the onset of the disease was obtained.

(3) In 17 instances the histories were conclusive of mussel infection.

(4) The curve of mussel-typhoid cases arranged in their weeks of commencement tallies closely with the importation of mussels into Birmingham.

(5) Mussel infection is one of the causes contributing to the autumnal rise of enteric fever.

(6) Some of the sources from which mussels are sent to the Birmingham market are known to be exposed to dangerous sewage contamination.

(7) 65 samples of mussels obtained on entering the Birmingham market from 22 different known sources were analysed bacteriologically.

(8) The results in terms of (a) the total number of organisms, (b) the number of glucose-fermenters, (c) the number of spores of Bacillus enteritidis sporogenes, and (d) the number of Streptococci shew that pollution to a dangerous degree of a large proportion of mussels placed on the market for human consumption exists.

(9) 14 experiments were carried out in relation to mussels subjected to mussels subjected to moist heat at 100°C.

(10) These shew that the ordinary method of cooking to mussels does not remove the risk of typhiod infection and that mussels may be heated in a steam steriliser at 100° C. continuously for as long as four and a half hours without sterilisation.

(11) Legisaltion is necessary to prohibit the gathering of mussels for human consumption from mussel beds exposed to sewage contamination.