bluuebunny/crossref_metadata_2025 huggingface dataset:
The measurement of the duration of infection in paratyphoid fever
Authors: George T. C. R. , Harvey R. W. S. , Thomson Scott
Published: May 2009

Cases of paratyphoid fever are often not diagnosed until the second, third or subsequent weeks of illness. When calculating clearance rates of a series of cases the calculations must be based only on the numbers known to be positive at the week under consideration. If based throughout on the total number of cases the rates of clearance in the early weeks are greatly reduced.

Cases for which laboratory records are incomplete must not be entirely rejected when calculating clearance rates but must be retained in the population for as long as they were known to be positive.

Analyses designed to show the duration of infection in paratyphoid fever can only be made with accuracy under the most favourable conditions.

A large number of cases of paratyphoid fever were repeatedly examined bacteriologically to establish the duration of the infection as distinct from the clinical illness. After an initial lag the proportion of cases remaining infected fell logarithmically until the carriers revealed themselves.

We are grateful to many medical officers for information about their cases, and to Dr Lewis Fanning and Dr Ian Sutherland for much helpful criticism.
The effect of storage on the coliform and Bacterium coli counts of water samples
Authors:   By the Public Health Laboratory Service Water Sub-Committee
Published: May 2009

This investigation has been concerned with the changes that occur in the coliform and faecal coli content of water samples on storage at room and refrigerator temperatures for 6 hr. as compared with those occurring after 24 hr. storage.

The examination was conducted by a 70-tube method using twofold diminishing volumes.

The percentages of samples showing a significant change corresponding to at least a doubling or halving of the coliform content on storage were: (a) at room temperature after 6 hr. 24.7%, and after 24 hr. 38.3%; (b) at refrigerator temperature after 6 hr. 25.0%, and after 24 hr. 33.9%. The percentages of samples showing a significant change in the faecal coli content on storage were: (a) at room temperature after 6 hr. 18.7%, and after 24 hr. 34.6%; (b) at refrigerator temperature after 6 hr. 10.4%, and after 24 hr. 25.0%. The changes were preponderantly decreases and most of the large changes occurred after 24 hr.

The investigation has shown that fewer changes occur after 6 hr. storage than after 24 hr. storage, and that storage for 6 hr. at refrigerator temperature is preferable to storage for 6 hr. at room temperature. Even so, some samples show significant changes after 6 hr. storage at refrigerator temperature; the coliform content is significantly altered in 25% of samples and the faecal coli content in 10% of samples.

Samples of water should, therefore, be examined as soon as possible after collection, certainly within 6 hr., and during the period of transport to the laboratory they should be kept cold, if possible by ice.
An investigation ofNeisseria gonorrhoeaeby a red cell sensitization technique
Authors: Chanarin I.
Published: May 2009

Two antigens, probably polysaccharide in nature, were extracted from smoothgonococci.

One of these could be adsorbed on to red cells and sensitized these cells to the action of a gonococcal antiserum. The factors concerned in this adsorption were investigated. The antigen, which was shown by a mirror absorption technique to be of two distinct types, was lost with the S-R change.

The second antigen was detected by its ability to fix complement in the presence of an immune serum.

It is suggested that these two antigens form a complex which determines the nature of the surface of the smooth gonococcus.

I wish to thank Dr J. C. Thomas, Provincial Pathologist, for the facilities for carrying out these investigations; Prof. M. van den Ende and Dr A. Kipps for helpful and constructive criticism; and Miss E. Bennett, Miss B. Jefferies, Mr L. Heitman, Mrs S. Maddison, and Mr G. C. Buckle for technical assistance.
Staphylococcus pyogenes: the antibiotic sensitivity of strains isolated from human carriers
Authors: Gould J. C. , McKillop Elizabeth J.
Published: May 2009

Strains ofStaphylococcus pyogenesable to grow in 0·1 unit/ml. of penicillin produced penicillinase and were regarded as resistant. The majority of the remaining strains had the same sensitivity as the standard sensitive staphylococcus.

Five hundred and three strains were isolated from pre-clinical medical students from 1950 to 1953, and 24% were penicillin-resistant. Two per cent were streptomycin-resistant and none were resistant to chloromycetin, aureomycin or terra-mycin. Two hundred and forty-six of the strains were isolated from persistent and intermittent carriers, but only 14% were penicillin-resistant.

Another 183 strains were isolated from persons unattached to hospital, and 14% were resistant to penicillin. Only one strain was streptomycin-resistant; one was chloromycetin-resistant and none were resistant to the other antibiotics.

Among persistent and intermittent carriers, more than 7 times as many penicillin-resistant strains were isolated from those who had had previous penicillin therapy as from those who had not.

It was concluded that the administration of antibiotic increases the number of resistant strains in the community.
The susceptibility of some desert rodents to experimental infections with Shigella and Brucella organisms
Authors: Floyd Thomas M. , Hoogstraal Harry
Published: May 2009

Desert rodents often have been used successfully as laboratory animals in parasitology (Abdel Azim & Cowper, 1950; Adler & Feldman-Muhsam, 1952; Delanoe, 1929; Kuntz & Malakatis, 1954; Nicolle, Anderson & Colas-Belcour, 1927; Sergent & Poncet, 1951 a, b) and virology (Durand & Laigret, 1932; Gear & Davis, 1942; Noury, 1948; Snyder, Zarafonetis & Liu, 1945; Van Rooyen & Danskin, 1944; Zarafonetis, 1945). However, with the exception of investigations into the role of some of these animals as mammalian reservoirs of plague (Ristorcelli, 1938; Tikhomirova, 1934; Wassilieff, 1933), no reports have been found of their use for experimental bacterial infections.
Viricidal action of ethylene oxide gas
Authors: Klarenbeek A. , van Tongeren H. A. E.
Published: May 2009

Investigation of the viricidal effect of a mixture of ethylene oxide and carbon dioxide on two viruses, Columbia SK and vaccinia, yielded favourable results. Since ethylene oxide also exerts a germicidal effect, it offers simple and inexpensive disinfection of certain materials, especially those of low thermostability.
An investigation into the viricidal action of Teepol, sodium hydroxide, propylene glycol and Dettol
Authors: Klarenbeek A.
Published: May 2009

Teepol, sodium hydroxide, and Dettol failed to exert a viricidal effect on Columbia SK virus. The same virus was inactivated by 90% propylene glycol after exposure for 24 hr. at 4° C. The viricidal effect of propylene glycol was neutralized by 0·2% furacine.
A localized outbreak of dengue fever in Kuala Lumpur: serological aspects
Authors: Smith C. E. Gordon
Published: May 2009

1. Sera from an outbreak of about forty cases of dengue fever due to dengue-1 virus have been studied using the neutralization, haemagglutinin-inhibition, and complement-fixation tests.

2. The neutralization test was the most specific and the complement-fixation test the least so.

3. The neutralization test is essential for clear identification of the causal virus by serological means, and serial serum specimens from each patient must be examined.

4. The haemagglutinin-inhibition test can be used to screen patients in outbreaks where some cases have been fully identified by neutralization tests.

5. Homologous neutralizing antibodies persist in high titre for at least 30 weeks after infection, while heterologous antibodies have disappeared by that time.

6. Both haemagglutinin-inhibiting and complement-fixing antibodies to homologous and heterologous viruses usually persist for at least 30 weeks, although the homologous titres tend to be highest.

7. The implications of these findings in serological surveys are discussed.

8. Some evidence suggesting the occurrence of inapparent infections during the epidemic is presented.

I am greatly indebted to my staff for help with this work: especially to my senior technician, Che Ali bin Mohamed Amin, and to Che Mohamed bin Omar who drew the figures.
The use of survival time in the analysis of neutralization tests for serum antibody surveys
Authors: Smith C. E. Gordon , Westgarth D. R.
Published: May 2009

An analytical method based on survival-time response is described for use in survey neutralization tests with the neurotropic viruses in mice. The method is simple and has been shown to give consistent and comparable results, which enable tests which have been carried out with different doses of virus to be compared.
Staphylococcus aureusin the infant upper respiratory tract: I. Observations on hospital-born babies
Authors: Hurst Valerie
Published: May 2009

Pernasal and throat swabs taken on 106 newborn babies showed that 99% harboured coagulase-positiveStaph. aureusby the time they left the hospital nursery. When the strains isolated from thirty-four of them were phage typed and tested for penicillin sensitivity, it was found that thirty-three (97%) carried at least one penicillin-resistant strain. Phage typing of their subsequent cultures, taken as they became older, demonstrated that they retained these strains for very long periods. Of the twenty-one still under observation at 6 months of age, eleven (53%) were carrying one or more of their original hospital strains, and an additional three (14%) still were consistently yielding an untypable strain believed to be identical to that acquired in hospital. Similarly, of those remaining under observation for the last 6 months of their first year, at least 50% continued to carry their hospital strains.

These babies frequently retained the hospital strains in their throats longer than in their noses. Although their nasal cultures often became negative after the first few months of life, the original hospital strains continued to be recovered from the throats. This would indicate that the throat culture is more accurate than the nasal culture in determining staphylococcal carriers among this age group. Antibiotic-resistant staphylococci in the infant throat may have considerable epidemiological significance, since babies tend to widely distribute their saliva.

The observations suggest that the staphylococci acquired at birth become a normal component of the upper respiratory flora, and may thus prevent new strains of staphylococci from becoming established later. This may explain why newborn babies retain the antibiotic-resistant staphylococci of the hospital much longer than do adult patients. Antibiotic-resistant strains among the general non-hospital population will be increased steadily by babies born in hospitals.
Resistance to reinfection in experimental mouse typhoid
Authors: Hobson Derek
Published: May 2009

Mice surviving infection with a strain ofSalm. typhimuriumof reduced virulence developed a progressive resistance to reinfection with virulent strains.

The degree of resistance was greater than that of vaccinated mice, although the primary infection had not caused any significant degree of natural selection or higher serum titres of O antibody.

The previously infected animals responded to reinfection with a virulent strain ofSalm. typhimuriumby gradually restraining bacterial growth. Many of the survivors eradicated the reinfecting strain.

The possible reasons for the difference between vaccinated mice and survivors of previous infection have been discussed.

I am indebted to the Medical Research Council for the provision of a grant towards the expenses of this investigation and to Mr T. Norris and Miss Italia S. Alderton for technical assistance.
Experiments with the soluble antigen of rabies in suckling mouse brains
Authors: van den Ende M. , Polson A. , Turner G. S.
Published: May 2009

A study has been made of the properties of soluble antigen in the brains of infant mice infected intracerebrally with the Flury strain of rabies virus.

Soluble antigen is produced at the same time as infective virus, and reaches a high concentration in a period of 2–3 days.

It can be partially purified by precipitation at pH 4·3. It is partially resistant to the action of trypsin, RNAse and DNAse. It is relatively stable at pH 6–10.

Experimental results suggest that the soluble antigen remains antigenically active after heating at 56° C. and treatment with 0·5% phenol or 0·35% formal-dehyde, but that such heating markedly reduces the ability to stimulate formation of neutralizing antibody.

Rabbits and mice appear to differ in the production of neutralizing antibody following immunization against soluble antigen in which residual live virus was inactivated by heat, phenol or formaldehyde.

It is suggested that this difference may depend on the different susceptibility to traces of incompletely inactivated virus remaining in the immunizing antigens.

The authors are grateful to Miss T. Madsen for her assistance in some aspects of this work. Dr N. Sapeika kindly made available facilities for the in vitro anaphylaxis experiments.

Financial assistance was received from the Nkana-Kitwe and Chingola Poliomyelitis Research Funds.
Observations pointing to the conjunctiva as the portal of entry in salmonella infection of guinea-pigs
Authors: Moore B.
Published: May 2009

In the course of salmonella epizootics in guinea-pigs due to Salm. enteritidis and Salm. typhi-murium, respectively, salmonella conjunctivitis was widespread, and conjunctival swabbing was found to be a more effective procedure for detecting the spread of infection than the examination of rectal swabs. Eye-swabbing with segregation of eye-positive guinea-pigs and their cage-mates was apparently successful in controlling two Salm. enteritidis epizootics.

Later experimental observations showed that the conjunctival route was a far more effective one for producing systemic salmonella infection in guinea-pigs than the oral route. The 50% spleen infecting dose by the conjunctival route was of the order of 100 organisms, while a dose of 100,000,000 organisms of the same strain of Salm. enteritidis was ineffective by mouth. Blood-borne invasion from the primary conjunctival lesion occurred by the lymphatic route. Gut infection of guinea-pigs infected experimentally throughout the eye was secondary to spleen infection and probably occurred by excretion of salmonellae through the gall-bladder.

The importance of the conjunctival route in natural salmonella infections of guinea-pigs was confirmed by goggling experiments, which showed that, except in animals with complicating conditions such as pregnancy, effectively goggled guinea-pigs were highly resistant to infection in environments heavily contaminated with Salm. enteritidis which produced high infection rates in ungoggled control animals.

I am very grateful to my technician, Mr G. Sandys, for his enthusiastic help, particularly with the goggling experiments.
The mechanism of the ‘Welsch phenomenon’
Authors: Banič S.
Published: May 2009

The disappearance of the resistant mutant from an artificial mixture of normal antibiotic-sensitive organisms and a resistant mutant after varying numbers of subcultures is known as the Welsch phenomenon. Welsch's observations have been confirmed and experiments devised to show that the resistant strain disappears because it grows more slowly than the normal sensitive strain which eventually, during the successive subcultures, overgrows it.
Streptococcal infections among children in a residential home: I. Introduction and definitions: the incidence of infection
Authors: Holmes Margaret C. , Williams R. E. O. , Bloom C. V. , Hirch Ann , Lermit Ann , Woods Eileen
Published: May 2009

1. In a children's home with an average population of about 460 children aged from 0 to 15 years, 473 attacks of acute sore throat, 354 attacks of otitis and 314

attacks of other acute febrile respiratory tract illness were recorded in the 30 months from November 1950 to April 1953.

2. The attack rate for all forms of illness and at all ages was higher among children in a reception group, who were mostly recently arrived in the home, than it was in the permanent residents.

3. Of all ifinesses with the principal signs or symptoms referable to the throat, the proportion that yieldedStreptococcus pyogenesrose from about 34 % in the 1–2-year- old children to about 74% in the children aged 10 years or more. Streptococcal sore throats made up about 8% and about 38 % of all febrile respiratory tract illnesses in the same two age groups.

4. The attack rate for streptococcal sore throat varied from month to month between 0 and 6 5 % of the children at risk; only one period of substantially increased prevalence was observed and there was no indication of any seasonal trend. Non-streptococcal sore throat varied between FO and 20 % per month. It was not possible to recognize any epidemics of streptococcal otitis; non-strepto coccal otitis had a definite winter prevalence associated with the rise in the total of non-streptococcal respiratory disease.

5. There was a slight indication that tonsillectomized children had rather milder attacks of sore throat than non-tonsifiectomized under the routine sulphamezathine treatment adopted. About 86 % of all children stifi harboured the causative streptococcus in their throat on discharge from hospital. The tonsifiectomized children lost their throat, but not their nose, streptococci in convalescence more rapidly that the non-tonsillectomized. Among throat carriers, the tonsifiectomized children carried streptococci in their nose more often than the non-tonsilectomjzed at all stages in their illness and convalescence.

6. Bacteriological examination of excised tonsils did not often reveal the presence of streptococci that had been undetected in throat swabs. Twenty-one of twenty- two children who had had a streptococcal respiratory tract ifiness treated with suiphamezathine within the 3 months preceding their tonsifiectomy were found to harbour the same streptococcus in their tonsifiar tissue; only four of eighteen children whose illness had been treated with penicillin still harboured the streptococcus.

Streptococcal infections in children. I 61
Epidemic Kerato-Conjunctivitis—An Adenovirus Infection
Authors: Sommerville R. G.
Published: May 2009

Two strains of adenovirus Type 3 were isolated from fifty-nine patients suffering from epidemic kerato-conjunctivitis. Serological examination of a further group of fifty-nine patients revealed that neutralizing antibody to adenovirus Type 8 usually developed when the duration of the disease exceeded 14 days, and that at the same time a smaller number of patients also developed low titre neutralizing antibody to Type 3 adenovirus. From the evidence presented it is suggested that adenovirus Type 8 was the infecting organism in the majority of cases, and that when neutralizing antibody to Types 3, 6 or 7 adenovirus was present this probably represented a non-specific effect of stimulation by a heterotypic strain of adenovirus. Insignificant antibody titres by C.F. tests were frequently associated with high titres of neutralizing antibody hi the late convalescent phase of the illness.

I would like to express my gratitude for assistance in obtaining material for the investigation to the following clinicians: Dr J. Winning, Dr J. Marshall, Dr A. Mellick and Dr A. M. W. Thomson of the Eye Infirmary, Glasgow, and to Dr E. McNaught of the Ophthalmic Institution, Glasgow; for supplies of adenovirus seed to Dr B. E. Andrews, Central Public Health Laboratory, Colindale and Dr D. A. J. Tyrrell, Virus Research Laboratory, Sheffield; and for technical assistance to C. McLean, F.I.M.L.T., H. G. Carson, F.I.M.L.T. and J. Kerr.
Some cultural characteristics ofStaphylococcus aureusstrains from superficial skin infections
Authors: Parker M. T.
Published: May 2009

1. A collection of 1389 strains ofStaphylococcus aureusof human origin was examined by the following tests: phage typing, antibiotic resistance, ability to inhibit the growth ofCorynebacterium diphtheriae, the egg-yolk reaction and the serum opacity reaction.

2. Nearly all strains ofStaph. aureusType 71 were penicillin resistant, inhibitedC. diphtheriae, gave a negative egg-yolk reaction, and produced a zone of opacity on horse-serum agar.

3. The penicillin resistance of Type 71 strains is unlikely to have arisen as a result of the therapeutic use of penicillin, and is probably a natural characteristic of the type.

4.Staph. aureusstrains which gave a negative egg-yolk reaction and a positive serum opacity reaction occurred almost exclusively in superficial lesions. The majority of them were members of Type 71, or were penicillin-resistant members of phage-group III. It is suggested that these organisms can cause superficial inflammation, but are usually unable to invade deeper tissues.

I wish to thank Dr A. J. H. Tomlinson for valuable information about his unpublished work on impetigo. Thanks are also due to many colleagues who have provided cultures and clinical information, to Dr R. E. O. Williams for typing phages, and to Mr L. E. Simmons for technical assistance.
A comparison of complement-fixation titres in poliomyelitis-infected tissue-culture fluids and mouse brains
Authors: Selzer Golda
Published: May 2009

Ultra-centrifugation of emulsions from suckling mouse brains infected with the MEF1 strain of poliomyelitis virus separates a non-infective antigen, or soluble antigen, from infective virus. This antigen is responsible for most of the complement fixation and explains the high titres obtained. On the other hand, the same virus, and also Mahoney, Type 1 poliomyelitis virus, grown in monkey kidney tissue culture, fail to produce this soluble antigen, and this is probably a factor in the low complement-fixing titres obtained in tests with these fluids.

The author would like to express her appreciation of Miss M. Butchart's valuable technical assistance.
Transmission of group A streptococci: III. The effect of drying on the infectivity of the organism for man
Authors: Rammelkamp Charles H. , Morris Alton J. , Catanzaro Frank J. , Wannamaker Lewis W. , Chamovitz Robert , Marple Earl C.
Published: May 2009

The sources of airborne bacteria within living quarters are minute droplet nuclei which remain suspended in the air following expulsion from a carrier and contaminated particles which have become suspended from dried environmental deposits. Since group A streptococci may be isolated from environmental deposits in populations experiencing an epidemic of streptococcal respiratory disease (Loosli, Lemon, Wise & Robertson, 1952), it has been assumed that contaminated particles of dust serve as an important reservoir of infection. Indeed, many of our measures employed to control respiratory infection in recent years have been directed against this reservoir.
The development of homologous neutralizing antibody during a Type 1 poliomyelitis epidemic
Authors: Miles J. A. R. , Austin F. J. , Caughey J. E.
Published: May 2009

1. Sera taken from seventy-nine individuals who had been examined for poliomyelitis antibodies shortly before a Type 1 epidemic, were examined for the development of antibodies to polio-virus 6 months after the epidemic.

2. Ten of eleven (91%) susceptibles aged 5–7 years, 44% of those aged 8–9 years, 25% of those aged 10–14 and only one of fifteen (7%) 15 years or more old had developed neutralizing antibodies to Type 1 polio-virus.

3. In the school which the younger subjects attended, one boy developed paralytic poliomyelitis while the school was in session, but the amount of minor illness in the epidemic period was not significantly different from the 3-year average.

4. The comparison between these findings and the notification rate for the province suggested that the chance of an infection with polio-virus during this epidemic, leading to a clinically recognizable attack of the disease, might have been as much as eighteen times higher in adolescents and adults than in the 5–9 age group.

5. The epidemiological significance of these results is discussed.

We have pleasure in acknowledging our indebtedness to Dr J. H. S. Gear for the report on the sera collected before the epidemic, to Dr W. Murphy, Medical Officer of Health, for data about notifications, to Dr A. M. Douglas for assisting by collecting some of the bloods, to the Principal and staff of John McGlashan College for their readiness to assist us at all times and to all those subjects who allowed us to take a further specimen of their blood for this investigation.
Brill–Zinsser disease; the possibility of its occurrence in Britain
Authors: Lawy H. S. , Beattie C. P. , Bensted H. J.
Published: May 2009

1. Of 318 Polish refugees now living in this country 30% gave a history of typhus fever; nearly half of these had complement-fixing antibodies to a titre of 1–5 or more to epidemic typhus. A further 12% without such a history similarly had these antibodies making a total of 22% of 318 refugees. None of the 174 British born controls had antibodies up to this titre.

2. Brill-Zinsser disease may occur from time to time among immigrants or visitors from typhus endemic areas to this country, but it is unlikely to be a serious problem.

3. The clinical diagnosis of Brill-Zinsser disease may not be easy because the characteristic rash is not always to be seen. Any patient of Eastern European origin or who has a history of typhus complaining of fever and severe headache should be examined serologically by the rickettsial agglutination or the complement-fixation test for specific epidemic typhus antibodies. The Weil-Felix reaction may be positive, but a negative result will not exclude a diagnosis of Brill-Zinsser disease.

We acknowledge with gratitude the help, interest and advice of Dr E. S. Murray, of the School of Public Health, Harvard University and Dr Janet Niven and also the technical assistance of Mr J. P. Brooks, FIMLT. We have to thank Messrs Lederle for their kindness in supplying the rickettsial antigens and in addition those who helped us to obtain the specimens and the volunteers who supplied them.
An improved assay method for neutralizing antibodies against influenza viruses
Authors: Groth S. Fazekas de St , Withell J. , Lafferty K. J.
Published: May 2009

1. A method has been developed for the assay of antisera against influenza viruses.

2. Surviving bits of allantois-on-shell serve as host tissue, eighty to one hundred units being provided by a single egg. The test is set up in plastic trays, and uses a simple synthetic medium.

3. The method has worked equally well with the ten representative strains of influenza virus tested. It surpasses the orthodox techniques of neutralization in mice or whole eggs as regards sensitivity, accuracy and economy.
The Antibody Response in Man Following Infection With Viruses of the pox Group: II. Antibody Response Following Vaccination
Authors: McCarthy K. , Downie A. W. , Bradley W. H.
Published: May 2009

Following primary vaccination no antibody was detected up to the tenth day. After this time neutralizing antibody and antihaemagglutinin were present in the majority of individuals, while, with the technique used, complement-fixing antibody was found in less than half those examined. Neutralizing antibody may be found in the blood more that 20 years after primary vaccination; by this time very few show antihaemagglutinin and then only in low titre. Complement-fixing antibody was not found more than 6 months after primary vaccination.

In revaccinated individuals the antibody response tended to be higher than after primary vaccination and, when it occurred, often appeared within a week.This suggeststhat prompt revaccination of smallpox contacts may offer even greater protection than does primary vaccination.

The neutralization test is a better measure of immunological response than are either of the other two tests, for these may give a negative result even though there may be a well-marked rise in neutralizing antibody. The ‘early’ type of reaction to revaccination was associated with an antibody response in only about half the subjects examined. In the remainder, the skin reaction, although identical in appearance, must be regarded as allergic in nature and not accompanied by increase in immunity.
The Dose-Response Relationship Between Influenza Viruses and the Surviving Allantois
Authors: Groth S. Fazekas de St , White D. O.
Published: May 2009

It is shown that bits of allantois-on-shell cut from any one egg do not differ either in susceptibility to infection by influenza viruses or in yield of haemagglutinin. For this reason the dose-response curve within any egg is Poissonian.

Bits cut from different eggs vary both in susceptibility and in haemagglutinin yield. Unlike in whole eggs however, the scatter is so small that it can be demonstrated only by refined tests done on a large number of subjects. For practical purposes the dose-response curve may still be taken as Poissonian.

Susceptibility and yield vary independently of one another.

The data are used to define the accuracy of infectivity tests in bits of allantois-on-shell; the expected errors are given both for straight replication and for tests done with different reagents, by different operators, or at different times.
Salmonellae and shigellae in a group of rural South African Bantu school children
Authors: Bokkenheuser V. , Richardson N. J.
Published: May 2009

1. Faeces from rural, outwardly healthy Bantu school children from a Native Reserve region have been bacteriologically examined seven times at regular intervals over a period of one year.

2. Of 75 children, 44·0% experienced at least one salmonella infection and 29·3% one shigella infection; considering the infections together, salmonellae or shigellae were recovered from 72·0% of the individuals. The observations are discussed and the view is expressed that over a period of one year, practically all children experience one, and many of them several, attacks by these pathogens.

3. In the majority of cases, the infections appeared to be subclinical and of short duration. There was no evidence proving the existence of chronic carriers.

4. Salmonelloses showed a seasonal dependence with the highest incidence in early summer, i.e. December. Shigelloses was distributed evenly throughout the year.

5. The recovered salmonellae were of twenty types.Salm. typhi, Salm. paratyphi A, BandCwere not isolated. Members of all shigella groups were encountered.

6. All the recovered strains from the Tlaseng area were sensitive to streptomycin, chioromycetin, terramycin, achromycin and neomycin, and most of them to aureomycin and erythromycin. In comparison, salmonella strains isolated from the Johannesburg urban area showed signs of increased resistance to the same antibiotics.

7. Water was probably implicated in the conveyance of the infections.

We should like to express our thanks to the Director of this Institute, Prof. E. H. Cluver, for permission to publish this paper; to Mr R. G. Robinson for assessing the micro-organisms' sensitivity/resistance to antibiotics; to Dr P. A. Christensen for statistical advice; and to Dr A. R. P. Walker (of the Human Biochemistry Research Unit, Council for Scientific and Industrial Research), who incurred the major portion of the expenses of transport by permitting us to accompany him during his investigation on bilharziasis and nutritional state in the Bantu school children.
An improved device for sampling bacterial populations on blankets
Authors: McQuade A. B. , Sutherland W. J. A.
Published: May 2009

One of the major difficulties in determining the cleanliness of blankets for use in hospital wards is the estimation of bacterial contamination remaining on the blanket after washing. Present procedures are either cumbersome or not readily reproducible. Procedures for measuring bacterial contamination on fabrics may be based on dispersion of the bacteria as an aqueous or as an airborne cloud. As aerial sampling has the advantages that it may be rapid and simple and can be used to sample blankets which have been washed with a bactericide the possibilities of this principle were investigated. A simple method has been developed (Blowers & Wallace, 1955) in which the blanket is scraped manually by the edge of an agar plate so that the bacterial dust is thrown on to the exposed agar surface, but this procedure is difficult to control. There are wide differences in surface properties of blankets, and consequently in the amount of fibrous material shaved off by the Petri dishes. Puck, Robertson, Wise, Loosli & Lemon (1946) worked on the principle of hitting an area of taut blanket and sampling the aerial cloud so formed, but as their apparatus was not convenient for routine sampling in wards an improved version has been developed.
Laboratory investigations of a carrier of multiple phage types of Salmonella paratyphi B
Authors: Bernstein A.
Published: May 2009

A carrier has been found of at least three phage types of Salmonella paratyphi B. Investigation has shown that phage-mediated conversion could account for this multiplicity of types according to the following scheme.

It is not possible, however, to exclude the actual occurrence of repeated infection with different phage types.

I am grateful to Dr E. S. Anderson of the Central Enteric Reference Laboratory, Colindale, for his interest and advice during the course of this investigation, and to Dr Helen A. Wright of the University of Edinburgh who provided the many cultures and so introduced me to this problem.
Variations in natural resistance to tuberculosis
Authors: Gray David F. , Graham-Smith Heather , Noble John L.
Published: May 2009

1. ‘Resistant’ and ‘susceptible’ species of animals appear to be more or less equally susceptible to lung infection with equal doses of tubercle bacilli. Therefore it is pertinent to ask whether recognized natural differences in species resistant are in fact significant. For example, in terms of death rates (i.e. of overall resistance) the C57 mouse is at least as susceptible to tuberculosis as the guinea-pig and much more so than man.

2. Resistant, moderately susceptible and susceptible strains of mice as determined by death rates when exposed to large infecting doses, were equally susceptible to intranasal infection with small numbers of tubercle bacilli.

3. A state of tolerance of the parasite by the host lasting for about 3 weeks was observed in all mouse strains, regardless of ultimate strain resistance.

4. Pre-allergic deaths commenced in all groups when the tuberculous processes left insufficient normal lung to support life, but the deaths stopped first in the resistant strain and last in the susceptible strain, coinciding approximately in each strain with the onset of allergy.

5. Acquired immunity, once established, appeared not to vary in quality from one mouse strain to another, at least during 3 months' observation.

6. Racial or strain variations in the resistance of mice to tuberculosis are therefore natural, only in the sense that speed of onset of acquired immunity is probably genetically determined for each strain.

7. It is suggested that both species and racial variations in natural resistance to pulmonary infection are insignificant. Differences in the subsequent course of the disease appear to be explainable by the rapidity, efficiency and duration of the acquired immune response.
Strontium 90 in dairy milk produced in central Europe during 1957–1960
Authors: Nosek J. , Santholzer W.
Published: May 2009

The connexion between radioactive fall-out and the fission products was demonstarted by Blifford, Lockhart & Baus (1956), and the connexion between radioactive fall-out and radioactive strontium was reported by Libby also in 1956. Previous to the publication by Santholzer, Macků, Podrimek & Horak (1958) and Santholzer (1959) of records relating to the increased radioactive fall-out in areas in Central Europe (50° 10′ N. lat., 15° 50′ E. long.) which were not far distant from the area occupied by these University buildings, we had already decided to follow regularly the strontium 90 (90Sr) content of cow's milk produced in the area concerned.
Vaccination of man with attentuated live adenovirus
Authors: Hitchock Griselda , Tyrrell D. A. J. , Bynoe M. L.
Published: May 2009

Eighteen volunteers were given live adenovirus attenuated by passage in pig kidney tissue culture. Thirteen were given adenovirus Type 7 and five were given adenovirus Type 4. All volunteers who were given Type 7 and who had no homologous neutralizing antibody on inoculation showed antibody rises. Except in one volunteer not in isolation no signficant symptoms were seen.

It is suggested that adenoviruses attenuated in this way might be useful for large-scale vaccination programmes.
The dissemination of Salmonella typhi, S. paratyphi A and S. paratyphi B through the organs of the white mouse by oral infection
Authors: Gerichter C. B.
Published: May 2009

A dose of 5 × 109S. typhi (strain Ty2) and S. paratyphi B (strain HB3) administered to white mice orally, caused an infection of various organs of the mouse, namely: spleen, liver, kidneys, lungs, gall-bladder, mesenteric lymph nodes, jejunum and of the blood stream. The percentage of infected spleens was higher than that of other organs.

With the above-mentioned dose of Ty2, the infection of the liver was found to be five times higher than that of the gall-bladder. The infection of the latter lasted for about 8–9 days, whereas that of the liver for 18–19 days.

The bacteria appeared in the various organs: liver, spleen, kidneys, and lungs in about 2 min. after oral infection, and in the blood stream after about 20 sec.

The speed and intensity of the invasion of micro-organisms from the gastrointestinal tract to the blood stream depends neither upon the volume of the dose (0·5 ml. or 0·1 ml.), nor upon the content of the mouse's stomach.

The M.I.D. for the blood stream of the mouse by oral infection is about 5 × 105 bacteria for Ty2, HB3 and AH6.

In blood samples collected by cardiac puncture 2–3 min. after oral infection, an average of 5 × 102 micro-organisms/ml. blood was found. The count of bacteria increased and reached its peak after 20 min. (about 3 × 103 bacteria). After that period, the number decreased: 1·6 × 103 after 1 hr., 8 × 102 after 2 hr. and 1·7 × 102 after 3 hr. In spite of this considerable decrease, the blood did not became sterile until after several days.

In the infected spleen (by oral infection) an inverse process was observed: at the beginning only a small number of micro-organisms was found (about 5 × 10/100 mg. spleen), but afterwards the number of bacteria increased (1·2 × 102 after 24 hr. and 5 × 102 after 4 days).

In mice infected by the subcutaneous route with a dose of 5 × 109 bacteria, the number of micro-organisms in the blood stream did not differ significantly from that found after oral infection, whereas infection by intraperitoneal route caused a severe infection. When 5 × 107 micro-organisms (LD50) were administered by intraperitoneal route, 107 bacteria appeared in the blood stream of the moribund mice while in the spleen about 4·1 × 107 were found.

The author wishes to express his appreciation to Prof. I. Gurewitch and to Dr R. Rozansky from the Department of Clinical Microbiology, the Hebrew University-Hadassah Medical School, Jerusalem, for their advice and criticism.
The use of new antigens in the complement-fixation test for acute poliomyelitis
Authors: Selzer Golda
Published: May 2009

A complement-fixation test for acute poliomyelitis using unheated antigens derived from suckling mouse brain infected with poliovirus Type 1 or Type 2 is described.

The results of tests in 62 patients clinically diagnosed as cases of acute poliomyelitis in a recent epidemic and in 26 controls are recorded.

The CF tests were positive in 100% of 53 cases with poliovirus Type 1 and/or Type 2 in stool. A positive result was obtained in 23 (76%) of 30 cases whose sera were examined in the first 7 days of illness.

Negative tests of the initial serum samples were found in 15 (28·5%) of 53 cases, but all these became positive in titres of 40 or 80 on testing of convalescent serum.

In 31 (69%) of 45 cases whose sera were re-tested between the 3rd and 4th weeks of illness the CF antibody levels rose, reaching titres of 80 or 160 in most instances. Of the remaining 14 cases only one dropped in insignificant degree (from titre 320 to 160) and the 13 stationary results had been positive in titres of 40–160 on initial tests most of which were performed in the 2nd week of illness.

Homotypic CF antibody response without crossing was found in 37 (71%) of 52 cases with Type 1 or Type 2 virus in stool. In the cases of crossing the heterotypic antibody response was either transient, diminishing or stationary in all and in only low titre in most instances.

In 26 control cases there were seven positive CF tests, but one of these was nonspecific, five were in lowest titres, and one case appeared to have had recent poliomyelitis infection.

Heating the antigens did not broaden the reaction. It caused only slight loss of potency except in two cases in which the CF titre increased substantially.

The antigenic preparation described appears to be superior to antigens of other origin in the diagnosis of acute poliomyelitis by complement-fixation tests, as positive tests are recognized earlier in the illness and the titres are higher. Homotypic results were obtained in all cases and no instance of false negative occurred in this series.

I would like to thank the medical staff of the Cape Town City Hospital for Infectious Diseases for the trouble taken in collecting stools and paired sera, and Prof. Kipps for his interest in this work. I am indebted to Miss Karin Larssen for valuable technical assistance.
Dulcitol–sucrose–salicin–iron–urea agar (DSSIU)—a new medium for differential diagnosis of Salmonellae
Authors: Papadakis J. A.
Published: May 2009

A new dulcitol–salicin–sucrose–iron–urea medium is described which, on the basis of a single-tube culture, tests the fermentation of three sugars, H2S production and urea hydrolysis.

On this medium 91% of 228 Salmonellae gave easily recognized characteristic reactions, simulated only by some strains of theBethesda-Ballerupgroup. Proteus strains and most paracolon strains gave equally characteristic pictures.

The reactions of some other Enterobacteria are described. It is suggested that the medium is good enough to deserve extended trial in routine work.
Measurement of the physical decay of aerosols by a light scatter method compared to a radioactive tracer method
Authors: Dimmick Robert L.
Published: May 2009

The physical behaviour of aerosols atomized into stirred settling chambers, or into rotating drums, was examined by a radioactive tracer method and by a light scatter method. With suitable corrections, there was no difference between the two methods of measuring of physical decay. The tracer method is advantageous in that the data so obtained are on an absolute basis, whereas data from scattered light measurements are relative. The latter method, however, is less time consuming, provides an immediate notification of instrument performance and does not require that material be removed from the aerosol chamber for sampling purposes.
Aerosol sampling methods for the virus of foot-and-mouth disease and the measurement of virus penetration through aerosol filters
Authors: Thorne H. V. , Burrows T. M.
Published: May 2009

Single and multi-jet liquid impingers and membrane-filters were found to be efficient sampling devices for aerosols generated from suspensions of the virus of foot-and-mouth disease (FMD). Concentration of the aerosol samples with an adsorbent, Attaclay, facilitated the detection of small amounts of virus. Sodium dodecyl sulphate could be used for elution as the virus of FMD is resistant to this anionic detergent.

The penetration of these aerosols through various air filtration media was determined using impinger samplers. A glass fibre paper was found to be the most efficient with a virus penetration of less than 0·001%.

We wish to thank Dr D. W. Henderson and Dr H. M. Darlow, of M.R.E. and Mr R. G. Dorman of C.D.E. Porton for valuable prefatory discussions and advice. We are also indebted to Miss S. Cartwright for inoculating mice, to Miss M. Shoobridge and Mr S. Taylor for technical assistance, and to Vokes Ltd. for supplying materials.
Staphylococcal nasal carriage in mothers, babies and staff in a maternity hospital
Authors: Anderson K. F. , Coulter J. R. , Keynes D. Ruth
Published: May 2009

The nasal carriage of 407 mothers before, during and after admission to a maternity hospital and that of their babies during and after hospital stay was investigated together with the nasal carriage by the hospital staff.

The nasal carrier rate among mothers admitted to hospital was 38%, 40% of these strains being resistant to penicillin.

The nasal carrier rate among the nursing staff was 38 and 72% of these were resistant to penicillin.

If a population is swabbed only once approximately 25% of the carriers will be missed. Those showing slight carriage were no more likely to be missed than those showing heavy carriage. The concentration of organisms in the nose is evidently varying continuously.

Heavy carriers are no more likely to transmit than light carriers and it is therefore not right to report on the profusion or otherwise of growth if that implies a greater chance of transmission.

The biggest increase in resistance among nursing staff strains occurred in the non-typable group which could be explained by resistance to phage developing concurrent with resistance to antibiotics.

The difference in phage-distribution between patient and staff strains centred in group II which formed 19% of patient strains but only 7% of hospital strains.

The carrier rate was no higher for those with a history of hospital admission within 12 months or without a history of staphylococcal sepsis.

Those giving a history of penicillin therapy had the same resistance rate as those without a history of such therapy.
Oral humatin (paromomycin) in chronic enteric carriers
Authors: Eastwood J.
Published: May 2009

A clinical trial to determine the effect of oral Humatin therapy on the course of the chronic enteric carrier state in a group of twenty-seven typhoid and paratyphoid B carriers is described. It is concluded that the drug when administered orally in this group of carriers fails in the dosage given to effect a cure of the carrier state.
Diagnostic uses of cholera bacteriophages
Authors: Mukerjee S.
Published: May 2009

1. Apart from strain identification of V. cholerae for epidemiological studies by phage-typing and determination of their S-R dissociation cholera bacteriophages may be utilized for other valuable diagnostic aids in the laboratory.

2. The universal susceptibility of V. cholerae strains to group IV cholera bacteriophage and universal lyso-resistance of El Tor vibrios to it provide a specific method for differentiating between the two species of vibrios. This test is simple and convenient for routine diagnostie use and should be of special value for identifying non-haemolytic El Tor vibrios, which are otherwise liable to be missed.

3. The marked insensitivity of the NAG vibrios to cholera bacteriophages, particularly their total insusceptibility to the phage of group II, enables these strains to be readily distinguishable from V. cholerae.

4. Cholera bacteriophages which are stable on maintenance and storage in the laboratory can conveniently be supplied absorbed on filter disks for the use of the smaller laboratories.
A method for preparing smallpox vaccine on a large scale in cultured cells
Authors: Kaplan C. , Micklem Lisel R.
Published: May 2009

A tissue culture system using chick embryo cells gave bacteria-free vaccinia virus suspensions of sufficient potency to use as a vaccine. Clinical trials with vaccines prepared by this method gave similar results to those with sheep lymph vaccine.