bluuebunny/crossref_metadata_2025 huggingface dataset:
A Survey by the sewage swab method of latent enteric infection in an urban area
Authors: Moore B , Perry Col. E. L. , Chard S. T.
Published: May 2009

By a combination of a swab sampling method, modern cultural techniques and Vi-phage typing, a survey for enteric organisms has been made of the sewerage system of a town of about 10,000 inhabitants.

The location of typhoid and paratyphoid B carriers by systematic swabbing of sewers in accordance with cultural findings has been proved feasible.

Two paratyphoid B carriers and one typhoid carrier were discovered by this method. Evidence was obtained of the presence of at least six other foci of paratyphoid infection in the town.

Paratyphoid bacilh were repeatedly isolated from a river flowing through the town. The possible role of river pollution in the maintenance of endemic enteric infection in the area is discussed.

The methods used in this survey might be applied with advantage to the elucidation of unsolved enteric outbreaks, to the control of food-handling establishments and to epidemiological studies of other infections in which the causative organism gains access to sewage.

We are indebted to Mr R. W. Pinney and Mr W. E. Coles, who did by far the greater part of the work of laying the sewage swabs and sending them to the laboratory; to Mr L. M. Blanchard, Surveyor, Sidmouth U.D.C., for his assistance with the preparation of maps of the area; to Dr A. Felix for his kindness in typing the enteric strains isolated; and to Mr R. N. Brown and Mr S. Barlow for much assistance in the development of cultural techniques.
Significance of tests for non-infectivity of foot-and-mouth disease vaccines
Authors: Henderson W. M.
Published: May 2009

An appreciation of the chance of failing to detect small amounts of infectivity is the main consideration in the design of any test for non-infectivity. The absence of infectivity can never be proved, and many samples must be tested and found negative before there is reasonable assurance that a supposedly non-infective vaccine is safe to use.

The highest percentage,p, of samples likely to be infective for various numbers of negative observations,n, has been calculated from the expression (1−p)n=Pfor different levels ofP, the chance of failure to detect a positive. For example, if 100 observations are made and found negative the percentage of infective samples would be unlikely (P= 0·05) to exceed 3·0 and highly unlikely (P= 0·01) to exceed 4·5. It is suggested that at least this number of observations be made.

The particular problem of detecting foot-and-mouth disease virus by inoculation of a susceptible host is considered in relation to the theoretical requirements of a test of sound design.

The multiple intradermal tongue inoculation of a number of cattle is the method that best meets these requirements. It is shown that this method is the most sensitive for the detection of foot-and-mouth disease virus, at least twenty observations can be provided by one animal, the presence of non-infective but antigenic material in the inoculum does not hinder the detection of a trace of active virus, and an estimate of the initial susceptibility of the tongue tissue of non-reactors can usually be obtained.

Although a much larger volume can be tested by subcutaneous inoculation, disadvantages of this route are shown to be that with some strains very large amounts of virus are required for infection, only one observation is provided by each animal, the presence of non-infective but antigenic material in the inoculum may mask the presence of active virus, and non-reactors to an immunizing dose of vaccine cannot subsequently be tested for a measure of their initial susceptibility relevant to this route of inoculation.

I am indebted to Dr J. O. Irwin, of the Statistical Research Unit, London School of Hygiene and Tropical Medicine, for advice on the use of the binomial distribution and for his helpful criticism of the manuscript; to Dr Ian A. Galloway, Director of this Institute for his interest and encouragement and to Mr W. J. Brownsea for technical assistance during the work described in this and the previous paper.
Effect of ACTH, cortisone, sphingomyelin, sphingosine and phenergan (antihistamine) in inhibiting the skin reaction in cattle sensitized toTrichomonas foetusantigen
Authors: Kerr W. R. , Robertson Muriel
Published: May 2009

1. ACTH, cortisone, sphingomyelin and sphingosine produce a delayed in-hibition of the skin reaction in cattle sensitized toTrichomonas foetusantigen when they are injected intramuscularly. The inhibition is greatest 6–9 hr. after injection of the inhibitor, but may sometimes be further delayed. This reaction is associated with an absolute lymphopoenia of slightly variable duration.

N-acetylsphingosine retains the desensitizing effect of crude sphingomyelin and is of much the same potency as cortisone acetate of Merck.

2. The lymphopoenia associated with the injection of ACTH and cortisone occurs also with sphingosine, and these three substances are also alike in not producing the desensitizing effect until some hours after the injection.

3. Phenergan, a synthetic anti-histamine, has a different action, and its desensitizing effect which appears to depend on a direct antagonizing of the oedema-provoking substance resulting from the junction of antibody and antigen (hapten) takes effect apparently as soon as the injected drug itself is present at the site of the injection of the specific testing fluid.

4. Methods of testing the capacity of the hormones and drugs to prevent the skin reaction locally and to nullify the action of thein vitroantigen-antibody mixtures which can produce a reaction in normal animals are described.

Phenergan alone of the substances dealt with has any power to act locally. Phenergan mixed with the antigen-antiserum complexin vitroprevents the formation of the characteristic swelling in a normal animal.

Phenergan mixed with the specific testing fluid prevents the development of the skin reaction when the mixture is injected intradermally into a sensitive animal.

Cortisone and sphingosine do not have this action.

We are indebted to the Medical Research Council for supplies of ACTH and cortisone and to Sir Charles Harington for N-acetylsphingosine.

The personal encouragement of Prof. H. G. Lamont and the support afforded by the Ministry of Agriculture, Northern Ireland, are gratefully acknowledged.
Observations on the antigenic structure ofPseudomonas aeruginosa
Authors: van den Ende M
Published: May 2009

Twenty-four selected strains ofPseudomonas aeruginosahave been classified on the results of precipitin tests with trichloracetic acid extracts into six serological groups.

This differentiation was confirmed by O agglutination.

Four of the six serological groups can be further subdivided according to their sensitivity to one or more of nine phages.

Alcohol treatment reduces agglutinability of some strains, particularly if alcohol is added to very concentrated suspensions of bacteria in the preparation of O suspensions.

The precipitation method has been applied to eighty successive strains ofPs. aeruginosaisolated, and with the available sera seventy-two could be placed into one or other of the six serological groups.

I am grateful to Mr G. S. Turner and Miss D. L. Deeks for their able and enthusiastic assistance in this work, and to all the members of my staff for their constant helpful co-operation.

The Virus Research Unit was in receipt of additional financial assistance from the Nkana-Kitwe and Chingola Poliomyelitis research funds.
The estimationin vitroof small amounts of diphtheria antitoxin by means of a haemagglutination technique
Authors: Fisher Stephen
Published: May 2009

1. Treatment of washed sheep erythrocytes with dilute solutions of tannic acid rendered them capable of adsorbing diphtheria toxin from solution. Diphtheria toxoid was not adsorbed under similar conditions.

2. Cells thus sensitized with diphtheria toxin were agglutinable by a proportion of children's sera and human cord sera; sera of rabbits, mice and horses, immunized with soluble or adsorbed diphtheria toxoid, also agglutinated sensitized cells, as did also the sera of children suffering from diphtheria and treated with antitoxic serum. Clear-cut results were usually obtained, but the end-point of titrations on horse sera was, in some cases, difficult to determine.

3. Using intradermal toxin neutralization tests, a highly significant linear relationship was demonstrated between the haemagglutinating titres of children's sera for the sensitized red cells, and the antitoxin content of their sera. The antitoxin content corresponding to the smallest detectable amount of haemagglutinating antibody was 0·008 unit per ml. serum.

4. The haemagglutinating titre was an accurate measure of the mean antitoxin level of a group of sera and a close measure of the antitoxin content of most specimens in individual tests.
Studies on the susceptibility of Rickettsia burneti to chemical disinfectants, and on techniques for detecting small numbers of viable organisms
Authors: Malloch R. A. , Stoker M. G. P.
Published: May 2009

1. The susceptibility of the Henzerling strain of R. burneti to phenol, formalin, ‘Lysol’, ‘Dettol’, ‘Cetavlon’, and ether was investigated.

2. Preliminary investigation of techniques showed that, with one passage, guinea-pigs, mice and fertile hens' eggs were of similar susceptibility to small numbers of viable organisms, but the greater feasibility of sub-passage from the eggs increased the sensitivity and made this the technique of choice.

3. Under the condition of testing, ‘Lysol’ was the most active disinfectant. Treatment of the rickettsial seed with 1% ‘Lysol’ at 37° C. was in fact the only effective method for destroying completely the infectivity in 3 hr.

4. Some living organisms survived contact for 3 hr. with each of the other chemicals in concentrations up to 1%. A rough quantitative comparison of these agents was made.

5. The failure of 1% phenol to destroy R. burneti raised the possibility of this organism surviving as a contaminant in vaccine lymph. This problem was investigated and is discussed.
The properties of differentSalmonellaVi antigens
Authors: Felix A.
Published: May 2009

The labile Vi antigens ofSalmonella typhi, Salm. paratyphi AandB, and ofSalm. typhi-muriumwere compared, especially in their response to various chemical and physical agents.

1. Inactivation by dilute acid:

(a) The TVi antigen is the most resistant to acid treatment, the BVi antigen is most readily inactivated and the AVi antigen holds an intermediate position.

(b) Pure Vi sera may be obtained by absorption with acid-treated bacilli, but this technique gives irregular results.

(c) Contrary to Kauffmann's statements, the TVi antigen is not ‘destroyed’ by acid treatment.

2. Inactivation by dilute alkali:

(a) All the Vi antigens so far tested are susceptible to dilute alkali.

(b) Complete inactivation, or extraction, of the Vi antigens is ensured when the yield of alkali-treated bacteria represents no more than 25% of the original bacterial count.

(c) The most reliable method of preparing a pure Vi serum is by absorption of the Vi + O serum with alkali-treated organisms of the same strain as that employed in immunization.

(d) Immunization with alkali-treated bacilli results in the elaboration of pure 0 antisera entirely devoid of Vi antibody.

3. Inactivation by heat (in aqueous suspensions):

(a) The TVi antigen is the one most readily inactivated, the BVi antigen is the one most resistant and the AVi antigen holds an intermediate position.

(b) These differences are only of minor significance, since similar differences have been established for the TVi antigen itself when it is contained in the two varieties of Vi strain of Salm. typhi.

4. Treatment with alcohol:

(a) Most of the properties of the threeSalmonellaVi antigens remain unimpaired by alcohol treatment.

(b) The physico-chemical behaviour of alcohol-treated or heated bacilli, as exemplified by agglutinability by pure Vi antiserum, depends on the presence of other constituents of the bacterial cell.

5. Treatment with formalin:

(a) The Vi agglutinability of the differentSalmonellais preserved undamaged for long periods of time. The 0 inagglutinability ofSalm. typhiis also well maintained.

(b) It is not yet known whether formolized AVi and BVi antigens undergo an alteration that leads to ‘functional deficiency’ of the corresponding antibody similar to that of the altered T Vi antibody.

6. Treatment with phenol produces a reversible inactivation of the agglutinogenic activity of the T Vi antigen but not of the A Vi and B Vi antigens.

7. The inadequacy of the symbols employed by Kauffmann for expressing the changed reactivity of differently treated antigens is emphasized.
The experimental infection of calves with Mycobacterium Ulcerans
Authors: Tolhurst Jean C. , Buckle Glen , Wellington N. A. M.
Published: May 2009

Skin lesions with histopathology similar to that seen in lesions in man have been produced in calves by the experimental inoculation of cultures of Myco. ulcerans. Sensitization of infected calves to mammalian tuberculin as well as to ulceranin has been demonstrated.

It is considered unlikely that cattle are a reservoir of infection for man.

The expenses of this investigation were met by a research grant from the Board of Management, Alfred Hospital.

We are indebted to Dr A. V. Jackson, Director of Pathology, Alfred Hospital, for the reports on histopathology.
The experimental reproduction of enterotoxaemia in piglets
Authors: Field H. I. , Goodwin R. F. W.
Published: May 2009

1. Whole cultures ofClostridium welchii, Type C (organisms plus toxin), produced enterotoxaemia and death when fed to new-born piglets.

2. The disease could rarely be produced by suspensions of washed organisms given in the same way but was readily initiated by feeding bacteria-free toxin from Type C cultures.

3. Piglets dying from enterotoxaemia induced by bacteria-free toxin showed all the extensive pathological changes of the natural disease; their intestines contained Type C organisms and far greater quantities of toxin than had been given by mouth.

4. Type C organisms could not be demonstrated in the intestines of piglets from healthy litters of the same age, although such animals were carriers of the Type A strain.

5. The clinical signs, with particular reference to the development of hypo-glycaemia, and the pathology of both natural and experimentally induced cases of enterotoxaemia are described.

6. In the light of these findings the pathogenesis and epidemiology of enterotoxaemia in the piglet are discussed.

We wish to thank Mrs B. L. Wardale and Mr P. J. D. V. Brett for general assistance. This study was aided financially by a general grant to one of us (R.F.W.G.) from the Agricultural Research Council.
Variation of host resistance to influenza viruses in the allantois
Authors: White D. O. , de St Groth S. Fazekas
Published: May 2009

1. Methods are described for altering the susceptibility of the surviving allantois to infection by influenza viruses.

2. Under natural conditions susceptibility is a linear function of age between 10 and 18 days of incubation. The drop is 0·11 log10unit per day for all strains of influenza tested.

3. In whole eggs this decline is masked by the effect of acid allantoic fluid which prevents infection when the pH falls below 6. The effect is not directed against the virus particle, nor does it do permanent damage to the cell, as surviving tissues are equally susceptible whatever the pH of the allantoic fluid that bathed themin ovo.

4. Surviving membranes can be made less susceptible by incubating the eggs at 35° rather than 38° C.; by maintenance for 24 hr.in vitro; by use of deficient or inappropriate medium. These methods lower susceptibility more for some strains than for others.

5. All treatments which lower susceptibility also increase its variation from egg to egg.
The comparative rodenticidal efficiency of five anti-coagulants
Authors: Bentley E. W. , Larthe Yvonne
Published: May 2009

1. Results are presented of palatability tests and chronic toxicity tests with five anti-coagulant rodenticides at a variety of concentrations against wild Rattus norvegicus, R. rattus and Mus musculus. These results are compared with similar data for warfarin. Estimates are also given of the acute oral toxicity of two of the five, fumarin and diphacinone, to white rats.

2. The toxicity of the compounds vis-à-vis warfarin is examined from the standpoint of the risks to domestic animals involved in their use as rodenticides.

3. Coumachlor, 2-isovaleryl-1, 3-indandione and 2-naphthyl-1, 3-indandione are considered to be less effective than warfarin against R. norvegicus. Their effectiveness against R. rattus remains to be demonstrated.

4. Fumarin appears to be about as good as warfarin against R. norvegicus and R. rattus at similar concentrations. It appears to be slightly less effective against M. musculus.

5. Diphacinone at 0·0025% is regarded as a good alternative to 0·005% warfarin against R. norvegicus. At 0·0125% it is probably more effective against R. rattus than is 0·025% warfarin. The two poisons are about equally effective at this strength against M. musculus, but diphacinone is probably slightly more dangerous for domestic animals.

6. The results of a small number of field trials with fumarin and diphacinone are briefly summarized.

So many of our colleagues and others have helped at some stage or other of our investigations that it would be tedious to mention them all by name. We must, however, single out for our special thanks Mrs M. Rowe and Miss E. Taylor who carried out a large number of the laboratory tests, Mr A. Taylor on whose chemical experience and facilities we have freely drawn and Mr C. H. B. Worrall, Miss B. Jones, Mr S. R. Surtees and Mr J. H. Cuthbert (Department of Agriculture for Scotland) who carried out the field trials.
Observations on the growth in nutrient broth of mixtures ofEscherichia colistrains, and of faecal specimens harbouring pathogenicEscherichia coliserotypes
Authors: Dixon J. M. S.
Published: May 2009

Experiments were made with five pathogenic serotypes and five non-pathogenicEsch. colistrains to study the competitive growth of mixed coli cultures in nutrient broth. In associations incubated at either 37 or 44°C. the organism inoculated in smallest numbers increased proportionately after 18 or more hours' incubation. The greater the initial disparity, the greater was the increase. Broth culture favoured the pathogenic strains only when these were numerically inferior in the inoculum. The tendency to numerical equation increased with increasing length of incubation.

A study was made of the use of nutrient broth as an aid to the isolation of pathogenicEsch. colistrains from the faeces of infants. 120 positive specimens were examined. Nutrient broth incubated at 44° C. was the most successful method, and when used as a complement to direct plating resulted in an additional 19·6% of positive specimens. The main value of nutrient broth as an enrichment method is in the examination of the faeces of suspected carriers and convalescent patients, in which the pathogen is likely to be outnumbered by non-pathogenicEsch. colistrains.

I wish to thank Prof. Scott Thomson for his advice and helpful criticism, and Dr R. W. S. Harvey for his interest and encouragement.
The fate of131I-labelled diphtheria toxin and toxoid in the skin of immune and allergic guinea-pigs
Authors: Long D. A.
Published: May 2009

Highly purified crystalline diphtheria toxin-protein, and toxoid prepared from it, were labelled with131I, without change of potency, and injected intradermally into immune and allergic guinea-pigs. It is probable that actively immunized guinea-pigs localize these antigens and that localization is due to hypersensitivity of a type that cannot be transferred with serum; it is possibly of the delayed (tuberculin-type) of allergy.

It is a pleasure to acknowledge the gift of highly purified (crystalline) diphtheria toxin, and toxoid prepared from it, from Dr C. G. Pope of the Wellcome Research Laboratories, England. Dr S. P. Masouredis of the Central Blood Bank of Pittsburgh kindly labelled these antigens, using the technique he devised. Dr W. J. Kuhns generously provided the human precipitating and non-precipitating diphtheria antitoxin*.

The collimator head was made by Mr J. Nechaj of the University of Pittsburgh.

All these collaborators gave me advice on matters of which I was ignorant; for this I am grateful.
Infra-red spectroscopy and its application to microbiology
Authors: Norris K. P.
Published: May 2009

Colorimeters and non-recording spectrophotometers for visible and ultra-violet light have been used for many years and are to be found in most microbiological laboratories. With the need for greater speed of operation, recording instruments are now coming into more general use. During the last two decades recording infra-red spectrophotometers have been developed and these have enabled the absorption measurements on micro-organisms to be extended into the infra-red region of the spectrum. Two factors have tended to retard the use of infra-red spectrophotometry. One is the high initial cost of the equipment and the other is the large absorption of infra-red radiation by water. Despite these difficulties, a considerable amount of work has now been done and it seems profitable to review the varied applications to which infra-red spectroscopy has already been put and to indicate the results which have been obtained by its use.
Fate of tubercle bacilli in early experimental infection of the mouse
Authors: Gray David F.
Published: May 2009

1. The question of a possible eclipse phase during the first week of experimental mouse tuberculosis has been examined.

2. Using fluorescence microscopy to examine sections and to perform counts of stainable bacilli for comparison with counts of culturable bacilli in the lungs it was found that bacilli multiplied very slowly during the first 5 days, and rapidly from about the sixth day onwards.

3. At all times there was close agreement between stainable and culturable bacilli in the lungs.

4. During the lag phase, the bacilli occurred as widely scattered, often weakly acid-fast cells that were difficult to defect by Ziehl–Neelsen staining.

5. Active removal of bacilli by phagocytes is believed not to be important at this stage.

6. After 5 or 6 days, clusters of bacilli, rapidly increasing in number and size and strongly acid fast, were readily detected in the lungs.
The influence of ambient temperature on the course of myxomatosis in rabbits
Authors: Marshall I. D.
Published: May 2009

Ambient temperature profoundly affects the mortality rate and symptomatology in rabbits infected with an attenuated strain of myxoma virus. Simulated summer temperatures allowed at least 70% of infected rabbits to recover, whereas only 8% recovered when held at simulated winter temperatures. Similar fluctuating high temperatures did not reduce the lethality of rabbitpox or of a highly virulent strain of myxoma virus.

On the chorio-allantoic membrane of developing chicken embryos the proliferation of myxoma virus was almost completely inhibited at 39° C., but the yield of rabbitpox virus was not reduced at this temperature.

The serological response and viraemia in rabbits held under different conditions of ambient temperature were investigated. Low temperatures resulted in high titres of circulating virus and soluble antigens, whereas at high temperatures anti-body appeared early. Haemolysin production was not affected by ambient temperature.

The widely variable response of rabbits infected with the attenuated strain of myxoma virus when held at mild temperatures indicates that there is a considerable variation in the innate resistance of the host to the invasion of the virus. This resistance is enhanced by high and reduced by low ambient temperatures, so that the host response is relatively uniform under these conditions. The precise nature of this innate resistance has not been elucidated.

Now that attenuated strains of virus are common and many rabbits exhibit enhanced genetic resistance, seasonal temperatures will have an important influence on the mortality rate in epizootics of myxomatosis.

It is a pleasure to acknowledge the skilled technical assistance of Mr A. Brand.
Some observations on the role of coliphages in the number of Escherichia coli in oxidation ponds
Authors: Pretorius W. A.
Published: May 2009

No evidence was found to support the view that coliphages as such play an important role in reducing the number of E. coli in sewage water when it is treated in oxidation ponds. Coliphages seem to have greater powers of survival than E. coli in oxidation ponds.
Transmissible drug resistance in an epidemic strain ofSalmonella typhimurium
Authors: Datta Naomi
Published: May 2009

Among 309 cultures ofSalmonella typhimurium, phage-type 27, fifteen, isolated from eight patients, were found to be resistant to the three drugs, streptomycin, tetracycline and sulphathiazole. This triple resistance could be transferred by growth in mixed broth culture to a strain ofSkigella sonneiand back again to sensitive cultures ofS. typhimurium. In whole cultures the resistance was stable, but spontaneous loss could be demonstrated in a small proportion of the organisms in such cultures. No elimination of resistance was demonstrated after treatment with acriflavine. Resemblances to the multiple drug resistance in enteric bacteria reported from Japan are noted.

The author is most grateful to Dr E. S. Anderson, Director of the Enteric Reference Laboratory, Colindale, N.W. 9, for phage-typing the cultures ofSalmonella typhimurium, and to Dr K. Patricia Carpenter, Director of the Dysentery Reference Laboratory, for supplying cultures ofSh. sonneiwhich were essential for the experimental work.
Dynamics of infection of the blood stream and internal organs of white mice withSalmonella typhiby intraperitoneal injection
Authors: Gerichter B. , Boros D. L.
Published: May 2009

An LD 50 doseS. typhi(strain Ty was injected intraperitoneally into white mice, and the number of micro-organisms was determined after 1 min. and subsequently, in the blood, and after 3 hr. and subsequently, in the spleen and liver. The course of the infection was observed for 34 days.

The number of bacteria gradually increased in the blood stream during the first post-infective hours. It was possible to differentiate by external signs from the sixth post-infective hour and onwards between sick animals and recovering ones. This difference corresponded to the bacterial concentration in the blood stream and internal organs.

In the sick animals the increase in the bacterial count of blood stream continued till 9–10 hr. after the inoculation, when it reached its first peak. During the following 8 hr. a clear decrease in the blood count was evident which was attributed to the ‘clearing mechanism’ of the blood. The onset of a new bacterial rise in the blood stream appeared 18 hr. after the inoculation and reached a second peak during the further 6–8 hr.

In contrast to the observed decrease in the bacterial blood count, a steady and gradual increase in the count of the internal organs was seen; it was steadily progressive till the exitus.

In the recovering animals a steady decrease in the bacterial blood count was recorded. Between 24 and 26 hr. the number of micro-organisms in the blood and spleen was found to be 400 times less in the recovering animals than in the moribund ones. From 48 hr. and onwards a slow and gradual decrease in the bacterial count of the surviving animals was observed. The blood became sterile after 25 days. In the spleen and liver of the surviving animals after 48 hr. a new increase in the bacterial count is evident, accompanied by hyperplasia of the spleen. The number of bacteria reached a new peak in the liver on the third day and in the spleen on the fourth day after the infection.

Subsequently a slow and gradual decrease in the bacterial count was observed in both organs, but even after 34 days a small number of persisting bacteria in the spleen and liver tissue may be found.
The bactericidal properties of compounds which protect living cells against freezing damage
Authors: Nash T.
Published: May 2009

Most air disinfectants fail at low relative humidity. Those which remain active appear to be the same compounds which, in other circumstances, can protect living cells against the lethal damage caused by freezing to low temperatures and then thawing. The compounds are either simple glycols, whose respective activities in the two fields are already known, or the weaker Lewis bases, whose air disinfectant properties have not hitherto been investigated. It is suggested that both freezing protection and bactericidal action are due to the special solvent properties of these compounds, which come into play when most of the water usually present has been removed, by freezing or by drying respectively.

I am indebted to Dr 0. M. Lidwell for the loan of air sampling equipment, and to Dr L. N. Owen and to the Shell Chemical Co. for the gift of various diols.
Observations on the distribution ofStaphylococcus aureusin the atmosphere of a surgical ward
Authors: Rountree Phyllis M. , Beard Mary A.
Published: May 2009

The environment of two contiguous surgical wards was examined over a period of twelve months by means of a slit sampler, settle plates and blanket sweep plates. At the same time, nasal swabs were taken each week from the patients and all cases of sepsis examined bacteriologically.

Phage typing of more than 3600 isolations ofStaph. aureusshowed that there was one predominant strain in the air, bedding, patients' noses and infected wounds.

There was no relationship between the total number of bacteria in the ward air and the numbers ofStaph. aureus.

The recovery of large numbers ofStaph. aureusfrom the air at certain periods was associated with a high contamination rate in the blankets and with an increased incidence of staphylococcal sepsis.

Not all nasal carriers ofStaph. aureuscontaminated their bedding. There was evidence that some patients became nasal carriers of strains of staphylococci previously isolated from their bedding.

Some evidence was obtained that blankets may play a role in the transmission of staphylococci from patient to patient.

This work was supported by a grant from the Australian National Health and Medical Research Council. Our thanks are due to Mrs Elisabeth Bradshaw for her technical assistance and to Prof. John Loewenthal for his interest and for permission to study his wards.
The incidence of sepsis in the Royal Air Force
Authors: Miller D. L.
Published: May 2009

In 1956–58 septic lesions in men of the R.A.F. accounted for about 3% of all admissions to sick-quarters or hospital and about 5% of admissions excluding respiratory disease; 1% of all men in the service were admitted with sepsis each year. Incidence fell with age, particularly up to the age of 25 years. The rates for women were about 50% higher.

Recruits experienced more than twice as much sepsis as trained men and boy apprentices. Officers had only half the admission rate of other ranks. These contrasts could have been explained by differences in age. There was no evidence of seasonal variation in the incidence of sepsis, but in recruits and boy apprentices epidemics of sepsis unrelated to season occurred.

I am indebted to Dr J. C. McDonald and Professor R. E. O. Williams for helpful criticism, to Professor P. Armitage for statistical advice and to the Director-General, Royal Air Force Medical Services, for permission to publish the results.
Chrome typhoid vaccine
Authors: Vella E. E.
Published: May 2009

1. Experimental typhoid vaccines, treated by 1% formalin and 0·02% chrome alum (KCr(SO4)2.12H2O), as suggested by Japanese workers were prepared and tested by the usual in vitro and in vivo tests.

2. Agglutination tests, antibody production in rabbits, active and passive mouse protection tests confirm the stability of the Vi antigen of the vaccine, if properly stored, and the good protection afforded to laboratory animals in both the active and passive mouse protection tests.

3. It is suggested that only a full-scale field trial in a typhoid endemic area can give the answer as to the real efficacy and/or superiority of the chrome vaccine over other typhoid vaccines.
Antibodies ofToxoplasma gondii
Authors: Fleck D. G.
Published: May 2009

1. That the number of toxoplasma organisms in the dye test affects the titre of the test serum is confirmed.

2. Evidence is presented that the toxoplasma cytoplasm-modifying substance present in the peritoneal exudate of mice injected with large numbers of toxoplasma organisms more than 3 days previously is probably antibody.

3. Various chemicals including detergents were capable, in high concentration, of producing a false positive dye test.

4. Evidence is presented that there are two complement-fixing antigens, one with a low sensitivity and a low density, the other with a high density and a sensitivity close to that of the dye test. Heating the heavy antigen to 56° C. for 1 hr. removes most of its anticomplementary effects without altering its complement-fixing activity.

5. The light antigen mentioned above was capable of producing a precipitation line in agar double-diffusion experiments, but did not inhibit dye-test antibody when mixed with an equal volume of antiserum in the dye test.

6. The heavy antigen inhibited dye test antibody when mixed with an equal volume of antiserum in the dye test.
Epidemiology of toxoplasmosis
Authors: Fleck D. G.
Published: May 2009

Sera sent for routine examination from hospitals in south England and Wales were examined and compared with sera from the normal population. Choroiditis was the only disease syndrome showing a significantly higher proportion of positives than normal.

Cats were shown to be unlikely vectors of toxoplasma infection, at least by scratching.

Thanks are due to many pathologists throughout the country who sent sera and details of cases. Normal children's sera were kindly sent to me by Dr A. D. Evans of the Public Health Laboratory, Cardiff, Dr A. Macrae, Colindale, and Dr Margaret Wilson, Public Health Laboratory, Sheffield. Dr Patricia Bradstreet kindly sent me details of requests for cat scratch antigen.

Mr R. Payne carried out the dye tests and Mr H. J. Godwin of the Department of Pure Mathematics, University College of Swansea, kindly checked the statistical calculations.

Many thanks are due to Dr R. J. Drummond and his staff of the National Blood Transfusion Service (Welsh Region) for supplying the sera from blood donors.
Optimum moving averages for the estimation of median effective dose in bioassay
Authors: Bennett B. M.
Published: May 2009

Optimum forms of moving averages are derived for the estimation of LD 50 in the situation where no assumptions are made about the form of the dose-response distribution. The theory is also applied to uses of moving averages based on the angular transformation of the percentage response. A numerical example illustrates this application, and its results are compared with the corresponding probit and logit estimates.
Growth, toxigenicity and virulence ofPseudomonas aeruginosa
Authors: Liu Pinghui V. , Mercer Charles B.
Published: May 2009

The virulence ofPseudomonas aeruginosaappears to depend on both its ability to grow in the serum of animals and its ability to produce various types of extra-cellular toxins. No strain ofPs. aeruginosalacking either of these qualifications was ever found to be virulent to animals.

The ability of various sera of animals to inhibit growth ofPs. aeruginosaappears to depend largely on their content of specific antibodies to each serological type of the surface antigens (the slime layer) and, therefore, susceptibility of animals to the infections ofPs. aeruginosa, even within one species, varies considerably from one individual to another.

This work was supported by a research career development award of the U.S. Public Health Service to the senior author (GM-K3–15).
An antigenic variant of the Hong Kong/68 influenza A 2 virus
Authors: Pereira Marguerite S. , Schild G. C.
Published: May 2009

Both the haemagglutinin and the neuraminidase of influenza A 2 virus have undergone progressive antigenic drift since this subtype first appeared in 1957.

In 1968 a strain showing a much greater antigenic difference was isolated in Hong Kong. This variant has been responsible for epidemics throughout the world in the past 2 years.

In the second year of its prevalence a small proportion of strains isolated showed a small but definite antigenic change, related principally to the haemagglutinin component.

This new variant formed about 4 % of all strains investigated and was detected in Britain, Portugal, France and New Zealand.
Recoveries of Salmonella ndolo from desiccates exposed to 100°C under various conditions with respect to desiccant, desiccant temperature and atmosphere
Authors: Annear D. I.
Published: May 2009

Desiccates of Salmonella ndolo dried in sodium glutamate have been exposed to 100° C. in air or in vacuo; in the presence of wet or dry P2O5; and with desiccant maintained at either 25° or 100° C. Of the eight treatments thus compared, rapid killing occurred where the desiccate was heated in vacuo and in the presence of dry P2O5 maintained at 100° C. There was little difference among the death-rates of the other seven treatments. Sublimation of the P2O6 with resultant attack on the desiccate would appear to be responsible for the rapid killing in the treatment where it was observed.
The hygiene and marketing of fresh cream as assessed by the methylene blue test
Authors:   Public Health Laboratory Service Working Party, Mogford Hilary
Published: May 2009

The hygiene and marketing of fresh cream in England and Wales was investigated by a working party of the Public Health Laboratory Service (PHLS) between 1 October 1968 and 31 July 1969. Thirty-one cream-producing dairies were visited and observations made in the light of the Code of Practice published by the Milk and Milk Products Technical Advisory Committee of the Ministry of Agriculture, Fisheries and Food, and the Scottish Home and Health Department. Suggestions are made in this report to strengthen the code.

A total of 5184 samples of fresh cream comprising 4385 heat-treated, 282 clotted and 517 untreated were examined. Details of production, age of the cream, distance and mode of distribution along the retail chain were available for most samples, and this history was, as far as possible, related to the laboratory findings. In the laboratory the samples were examined by the methylene blue test, colony count, conform andEscherichia coliI test and for pathogens.Staphylococcus aureuswas grown from 59 out of 3417 samples of cream; 54 of these were from untreated cream. Phage typing indicated that a proportion of these strains were of animal, presumably bovine, origin. Other human pathogens isolated included one each ofSalmonella typhimurium, Brucella abortus, E. colitype O126 andClostridium welchii.

It appeared that heat-treated cream was much better, bacteriologically, than untreated; and that large dairies, in general, had better premises, more hygienic methods of preparation and the advantages of mechanical filling and capping of cartons; thus they offered the consumer a better product, bacteriologically, than some of the smaller dairies.

A statistical analysis of the results of the tests used showed the methylene blue test, in spite of some anomalies, to be of more use as a screening test than any of the others. As this test is cheap and easy to carry out, the working party thought that it should be the test of choice. In view of the known anomalies, however, the working party recommends that the test should remain a screening or advisory test and have no penal function. Results should be reported as follows: cream not decolorizing the dye in 4 hr. at 37° C. (± 0·5°) after overnight incubation at 20° C. (± 0·5°) would be accepted as satisfactory; between ½ and 4 hr. at 37° C. (± 0·5°) as fairly satisfactory; but if the dye were decolorized at the end of the overnight incubation the sample would be provisionally classified as ‘unsatisfactory; requires further investigation’. A repeat sample would then be examined. If samples were repeatedly unsatisfactory, consultations would be arranged between the local authority, the laboratory and the dairy, with perhaps inspection of the dairy premises and retail storage conditions and further, more searching tests on samples made in an effort to eradicate production faults.
Pyocine typing as an epidemiological marker in Pseudomonas aeruginosa mastitis in cattle
Authors: Ziv G. , Mushin Rose , Tagg J. R.
Published: May 2009

Pyocine typing was used for the characterization of 134 Pseudomonas aeruginosa strains isolated from bovine mastitis. The scheme of Gillies & Govan (1966) was adopted with some modifications, and the procedure gave 89·6% typability. Pyocine type 1 strains were most commonly encountered and were followed in frequency by types 10 and 3. The introduction of two additional indicator strains allowed for division of these types into subtypes.

In spite of some limitations, discussed in the paper, the pyocine typing scheme proved to be useful in ‘marking’ P. aeruginosa strains and in following their association with bovine mastitis in various herds.
Pseudomonas aeruginosa in a Regional Burns Centre
Authors: Dexter F.
Published: May 2009

The construction of a Regional Burns Centre in Pinderfields General Hospital, Wakefield, presented an opportunity to study Pseudomonas aeruginosa infection in patients with extensive burns. During the first year (Barclay & Dexter, 1968) a system of disinfection and bacteriological control created conditions permitting more detailed studies to be undertaken which resulted in a significant reduction of infection and cross-infection.
Investigations of Allerton-type herpes virus infection in East African game animals and cattle
Authors: Plowright W. , Jessett D. M.
Published: May 2009

Neutralization tests with a strain (BA) of Allerton-type herpes virus, derived from a buffalo (Syncenis caffer) were carried out on 924 sera from 17 species of E. African game animals and on cattle sera from Tanzania (2001), Kenya (792) and Uganda (410).

Buffalo populations throughout E. Africa showed a very high rate of infection, with all animals over 2 years of age serologically positive. Antibody was present in some giraffe, waterbuck and hippopotamus sera and, less frequently, in impala, eland, bushbuck and oryx. Data are provided on the titres of positive samples; the mean titre of buffalo sera increased with age.

Cattle in many localities of N. Tanzania and S. Kenya showed a very high rate of infection, 85–95% of sera from animals more than 2-years old containing antibody; the titres recorded were lower than those in buffaloes. Very high infection rates were also found in Karamoja and Teso (Uganda) and also in some other areas of Kenya, whilst a considerably lower incidence of infection was detected in W. Nile Province of Uganda and in central Tanzania. Differences in infection rates may have been related to herd size and husbandry practices.

It was shown that a wave of infection was probably spreading through cattle in N. Tanzania at about the same time as an outbreak of disease occurred in buffaloes and it is suggested that virus transmission may have been by biting flies.

No clinical signs attributable to the virus were reported in cattle but mouth lesions similar to those recorded in buffaloes, or nasal lesions, could have passed undetected. Allerton-type virus probably produces a range of clinical syndromes in cattle, closely resembling those associated with some herpes viruses in primates but infection is seldom related in the field to either pseudo-lumpy skin disease, mammillitis or stomatitis.
The evaluation of a live salmonella vaccine in mice and chickens
Authors: Knivett V. A. , Stevens W. K.
Published: May 2009

Mice vaccinated with a live attenuated strain ofSalmonella dublinwere protected against heavy challenge infections ofS. dublin, S. typhimurium, S. choleraesuisandS. anatum. Oral and subcutaneous vaccination were equally effective. When day-old chicks were orally vaccinated and subsequently challenged withS. typhimurium, the growth of the challenge organism was considerably reduced or eliminated from the livers of the vaccinated chicks whereas most of the non-vaccinated were heavily infected. Field trials with vaccinated day-old chicks showed that they suffered no setbacks in growth, stress, loss of appetite or adverse side effects.
The British reference preparation for influenza virus haemagglutinin
Authors: Westwood M. , Woodward P. M. , Perkins F. T.
Published: May 2009

The two methods for measuring the haemagglutinin content of an influenza virus suspension are the haemagglutinating (HA) and chick cell agglutinating (CCA) techniques and both measure the same biological activity. With the establishment of an international reference preparation for influenza virus haemagglutinin (type A), however, it seems logical to express the haemagglutinin content of influenza vaccines in international units. Accordingly a collaborative study was arranged in order to obtain agreement on the number of units to be assigned to a British reference preparation for influenza haemagglutinin. It was agreed that the preparation contains 190 i.u. per ampoule and 1 i.u. is contained in 0·0622 mg. of the dried material.
Strontium chloride B and E.E. enrichment broth media for the isolation ofEdwardsiella, SalmonellaandArizonaspecies from tiger snakes
Authors: Iveson J. B.
Published: May 2009

Strontium chloride B medium and E.E. broth have been found effective in the recovery ofEdwardsiella, SalmonellaandArizonaspecies from the cloacal contents of tiger snakes (Notechis scutatus). Strontium chloride B medium was superior to E.E. broth.

At least one bacterial species was detected in each of the 60 reptiles examined, and all three organisms were recovered from each of 29 snakes on a single examination.

Strontium chloride M, strontium selenite and Rappaport enrichment media and bismuth sulphite agar, although satisfactory for the isolation ofSalmonellaandArizonaspecies, were found unsuitable forEdwardsiella tarda.
Beta-haemolytic streptococci in saliva
Authors: Ross P. W.
Published: May 2009

Viable counts of beta-haemolytic streptococci per ml. of saliva were made in the following groups: (1) children with acute streptococcal sore throat, (2) children with acute non-streptococcal sore throat, (3) children who had no sore throat but were streptococcal throat carriers, (4) children who neither had a sore throat nor were streptococcal throat carriers.

The mean counts from cases of streptococcal sore throat and from streptococcal carriers were respectively 1·4 × 106 and 2·5 × 105 per ml.

In a comparison of the efficiency of the throat swab, sublingual swab and specimen of saliva in isolating beta-haemolytic streptococci from the upper respiratory tract, culture of saliva produced the best results.
Interaction of porcine mycoplasmas with fresh animal serum
Authors: Roberts D. H.
Published: May 2009

When fresh animal serum was dropped onto seeded mycoplasma agar plates, inhibition of growth frequently occurred. This effect was dependent on the mycoplasma serotype and on the animal species from which the fresh serum came. This activity of fresh animal serum was heat-labile and would not diffuse through the agar medium. Growth of all the porcine mycoplasma serotypes was inhibited by fresh sheep serum.M. hyorhinis, M. hyopneumoniae, B 3 and the P 45 strains were insensitive to fresh horse serum. The addition of fresh horse serum to specificM. hyorhinisrabbit antiserum-impregnated disks appeared to have a synergistic effect and the combination ofM. hyorhinisantiserum-impregnated disk and fresh horse serum always inhibited the growth ofM. hyorhinisstrains.