bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolations of subgenus III salmonellas (arizonas) in Cardiff, 1959–1971
Authors: Harvey R. W. S. , Price T. H. , Hall Mary L. M.
Published: May 2009

Isolations of subgenus III salmonellas (arizonas) made in the regional Public Health Laboratory, Cardiff, between 1959 and 1971 are reviewed. The techniques of isolation are listed for the various materials examined. The necessity of using bismuth sulphite agar as a plating medium is stressed, as some strains might appear on brilliant green MacConkey agar as rapid lactose fermenters and be missed. The serotypes isolated in Cardiff are discussed with reference to isolations by other authors. The culture of a subgenus III salmonella from pig faeces is described. It is thought that this is the first record of such an isolation from a pig in the United Kingdom.
Fluctuations in the titre of antibody to a soluble antigen of myxoma virus in field populations of rabbits,Oryctolagus cuniculus(L.), in Australia
Authors: Williams R. T. , Dunsmore J. D. , Sobey W. R.
Published: May 2009

Results are presented on tests carried out over the past 5 years to measure the antibody titre of various rabbit populations to a soluble antigen of myxoma virus. In an unexpectedly high percentage of immune rabbits the antibody fell below measurable titres, and later rose to measurable titres without the advent of an observable epizootic of myxomatosis. The re-stimulation of the immune response is discussed in terms of re-infection and virus reactivation.
An ‘in-production’ method for testing the sterility of infusion fluids
Authors: Rycroft J. A. , Moon D.
Published: May 2009

The addition of dehydrated broth powder to a random selection of bottles from each batch of infusion fluids before sterilization, followed by incubation of the bottles after sterilization, provides a method of sterility testing which possesses many advantages over the traditional method of culturing small samples from bottles after sterilization.
The quantitative bacteriology of some commercial bivalve shellfish entering British markets
Authors: Ayres P. A.
Published: May 2009

Incidents of non-specific illness associated with the consumption of oysters have highlighted the lack of published information on the bacteriology of shellfish suitable for consumption. Investigations showed that the majority of molluscan shellfish entering English markets conform to the accepted standard of less than 5 Escherichia coli/ml. tissue. The numbers of E. coli were related to the sanitary quality of the growing area but no relation could be established between numbers of E. coli and coliforms, faecal streptococci or Clostridium welchii. The numbers of non-specific bacteria varied considerably but shellfish from sources associated with non-specific illness yielded relatively high counts at 37° C. The results showed that there was no justification for a standard based on total plate counts, which often exceeded 106/g. Such a standard would have to be coupled with spoilage or the incidence of non-specific illness. The relation between the numbers of non-specific bacteria growing at 20 and 37° C. appears to be a useful measure for assessing the likelihood that raw shellfish are a public health risk.
The effect of thermal pollution on the distribution ofNaegleria fowleri
Authors: De Jonckheere J. , Van Dijck P. , van de Voorde H.
Published: May 2009

The distribution in the environment ofNaegleria fowleri, the causal agent of primary amoebic meningoencephalitis has been investigated in this study.N. fowleriwas isolated only from a thermally polluted canal. These amoeboflagellates were not isolated from another thermally polluted canal in the neighbourhood indicating that, apart from high temperature, other factors are involved in the selective proliferation ofN. fowleri.This species was absent in all other samples originating from two canals, a stream, two lakes, several reservoirs and slow sandfilters of a water supply service and also a water distribution network. Many other amoebae able to grow at 42° C. were found in different places. Most of theN. fowleristrains isolated were not virulent for mice, although they showed all the characteristics of the pathogenic strains.
Endemic infection in surgical wards
Authors: Berbee Gertruide A. M. , van Furth R. , Noble W. C.
Published: May 2009

Endemic infection in male surgical wards has been studied during three periods. There was some infection due to gram-negative bacilli, though Staphylococcus aureus remained as the single most important pathogen even in the absence of epidemic spread. Beta haemolytic streptococci were isolated in large numbers from the lesions of four patients with deep wound infection. Changes introduced in the pattern of post-operative care reduced sepsis due to Staph. aureus, reduced the severity of wound infection and apparently decreased the need for antibiotic therapy. Patients who became infected were retained in hospital longer than those who escaped clinically apparent infection.
Observations on the epidemiology of Rift Valley fever in Kenya
Authors: Davies F. G.
Published: May 2009

The epizootic range of Rift Valley fever in Kenya is defined from the results of virus isolations during epizootics, and from an extensive serological survey of cattle which were exposed during an epizootic. A study of the sera from a wide range of wild bovidae sampled immediately after the epizootic, showed that they did not act as reservoir or amplifying hosts for RVF.

Virus isolation attempts from a variety of rodents proved negative. Rift Valley fever did not persist between epizootics by producing symptomless abortions in cattle in areas within its epizootic range. A sentinel herd sampled annually after an epizootic in 1968 revealed not one single seroconversion from 1969 to 1974. Certain forest and forest edge situations were postulated as enzootic for Rift Valley fever, and a small percentage of seroconversions were detected in cattle in these areas, born four years after the last epizootic. This has been the only evidence for the persistence of the virus in Kenya since 1968, and may be a part of the interepizootic maintenance cycle for Rift Valley fever in Kenya, which otherwise remains unknown.
An investigation of the family background of acute haemophilus infections of children
Authors: Turk D. C.
Published: May 2009

Nose and throat swabs, for culture ofHaemophilus influenzaetype b, and blood samples, for measurement of antibodies specific for that serotype, were collected from members of 28 families from which children had been admitted to hospital with acuteH. influenzaetype b infections (mainly meningitis or epiglottitis). The patients with meningitis were younger than those with epiglottitis and had more siblings, with a marked predominance of sisters. Investigations within a few days of admission of the affected children to hospital detected carriers ofH. influenzaetype b (19 altogether) in 13 of the 28 families, including 9 of the 13 families with 3 or more children. Members with raised antibody titres forH. influenzaetype b (suggesting the presence of the organism for at least a few weeks) were found in 17 of the 25 families from which blood samples were obtained, including all 11 families with 3 or more children. Most of the patients probably acquired their infections from within their own families, and siblings under 11 years old were of predominant importance both as carriers and as potential sources of the patients' infections. Persistence of the organism within families for up to 6 months was demonstrated. Possible reasons for the difference in age-incidence between haemophilus meningitis and epiglottitis and for the occurrence of the former in babies with older sisters are suggested, and also a possible connexion between the results of this survey and the likely value of immunization againstH. influenzaetype b.
Salmonellosis in Indonesia: phage type distribution of Salmonella paratyphi A
Authors: Sanborn W. R. , Hablas R. , Komalarini S. , Sinta  , Trenggonowati R. , Sadjimin T. , Atas  , Sutrisna
Published: May 2009

The distribution of phage types among 221 human strains of Salmonella paratyphi A in Indonesia was studied. Approximately 50% were phage type 5, a rare type elsewhere in the world. Most other isolates were the cosmopolitan phage type 1. The ratio of phage type 1–5 was compared for two cities on Java, Jakarta and Yogyakarta. The ratios were significantly different, phage type 5 predominating in Jakarta. The ratio of phage types among 10 S. paratyphi A strains isolated from Jakarta river water was similar to that found in Jakarta patients.
A comparison of typing methods forSerratia marcescens
Authors: Anderhub B. , Pitt T. L. , Erdman Y. J. , Willcox W. R.
Published: May 2009

A simple method for the bacteriocine typing ofSerratia marcescenswithout the use of induction was sought. The results of a mutual inhibition experiment with 89 unrelated cultures indicated that a bacteriocine-susceptibility method would give more discrimination between strains than would a bacteriocine-production method. A cross-streaking technique for bacteriocine-susceptibility typing without previous induction was developed, and its performance was compared with that of another susceptibility-typing method in which cell-free lysates of the producer strains were obtained by induction with mitomycin C.

Replicate typing of the same collection of cultures by both methods indicated that small variations in pattern were common and that larger variations occurred occasionally. Differences in pattern of less than two strong reactions in the mito-mycin-C induction method, and of less than three strong reactions in the cross-streaking method, should therefore not be taken as evidence that strains can be distinguished.

Sets of cultures ofSer. marcescens, 178 in total, from a number of supposed incidents of infection in hospitals, were used to evaluate the two bacteriocine-typing methods; all of the cultures were also O serogrouped. Comparison of the typing patterns of members of the same O serogroup from clear-cut incidents of infection confirmed that results of acceptable reliability could be obtained by either bacteriocine-typing method by the application of the appropriate 'difference' rule. When so interpreted, the cross-streaking method appeared to be slightly the more discriminatory.

The greatest discrimination between strains was obtained by the use of a 'hierarchical' typing system in which the strains were first O serogrouped, and the cross-streaking method of bacteriocine typing was then used to make subdivisions within O serogroups.
A selective oleic acid albumin agar medium for the cultivation ofMycobacterium bovis
Authors: Gallagher J. , Horwill D. M.
Published: May 2009

The modification of Middlebrook's 7H11 oleic acid albumin agar medium by the addition of fresh bovine serum and lysed sheep red cells to encourage growth ofMycobacterium bovisis described. The improved medium was made selective by the addition of antibiotics and a comparative trial of this medium and the guineapig test in the isolation ofM. bovisfrom badger tissues is reported. A close agreement between the two tests was found; the guinea-pig test detected 95% of all isolations and culture detected 91%.
Attempts to control clothes-borne infection in a burn unit: I. Experimental investigations of some clothes for barrier nursing
Authors: Hambraeus Anna , Ransjö Ulrika
Published: May 2009

Clothes-borne transmission is an important way of spread of infection from patient to patient which is not interrupted by common cotton gowns. New barrier garments were designed from spun-bonded olefin that, in particle penetration tests, was 100 times better as a filter than cotton cloth. Three designs, a gown, a loose coverall and a close coverall, were compared with each other and with conventional cotton gowns in experimental exercise and nursing procedures. Staphylococcus aureus from burned patients were used as markers. The close coverall was 4–7 times better than the loose coverall or gown in preventing the soiling of clothes worn underneath it, but appeared to permit substantially more transfer from garments underneath it to a mock ‘patient’ and to the air than did the looser garments. A cotton gown reduced the soiling of clothes underneath it by more than 10 times and the contamination of a mock patient by more than 30 times as compared with no barrier garment. The close coverall further diminished the contamination of clothes but not the transfer to the patient. The possible mechanisms for the discrepancy between particle transmission tests and experimental procedures are discussed.
Surveys of hospital infection in the Birmingham region: I. Effect of age, sex, length of stay and antibiotic use on nasal carriage of tetracycline-resistant Staphyloccus aureus and on post-operative wound infection
Authors: Ayliffe G. A. J. , Brightwell K. M. , Collins B. J. , Lowbury E. J. L. , Goonatilake P. C. L. , Etheridge R. A.
Published: May 2009

Cross-sectional surveys of infection in relation to ward structure and practice were made in 38 hospitals between 1967 and 1973, including repeat surveys in 12 hospitals. The survey team (a research nurse and a senior microbiologist or technician) visited one ward a day and entered data on patients, including appearance of wounds seen at change of dressings, on the structure of the ward, and on ward practices; bacteriological swabs were taken from noses of all patients and staff of wards visited and from infected or open wounds, also from some environmental sites. Effect of age, sex, length of hospital stay and antibiotic use on carriage of tetracycline-resistant Staphylococcus aureus and on post-operative sepsis are considered here.

Clinical infection (sepsis), further classified as ‘severe’, ‘moderate’ or ‘mild’ in accordance with a code of physical signs, including inflammation and suppuration, was found in 6·1% of clean undrained operation wounds. Drained wounds and those through hollow, heavily colonized viscera (‘contaminated’ wounds) had higher sepsis rates than undrained and ‘clean’ wounds; there was less sepsis with closed drainage and with small drains. Staph. aureus (24%) was the commonest single bacterial species, but gram-negative bacilli (50%) were found in a much larger proportion of septic wounds. The results showed that the infection rate was lowest among patients between 20 and 40 years old. Infection was significantly more common in male than in female patients.

Nasal carriage of tetracycline-resistant Staph. aureus, used as an index of hospital-acquired infection, was commonest in geriatric patients and least common in gynaecological patients. There was correlation between nasal carriage of tetracycline-resistant staphylococci and age of the patient, length of hospital stay, sex, (male greater than female), operative treatment, and treatment with tetracycline, ampicillin and nitrofurantoin, but not with penicillin.
Effects of antibiotics on the survival ofSalmonellain the American cockroach
Authors: Klowden Marc J. , Greenberg Bernard
Published: May 2009

The faecal survival ofSalmonella typhimuriumorally administered to restrained American cockroaches maintained on an antibiotic diet was investigated. Significant reductions in median numbers of total aerobic faecal microorganisms were noted in insects fed antibiotics daily, and whenSalmonellawas introduced to this modified micro-environment, it persisted for 44 days in all specimens. Multiplication of the pathogen was also observed in these insects, with numbers often exceeding 103times that of the initial input. This differs significantly from our previous results showing that the pathogen is unable to multiply in conventional cockroaches. Attempts to restore the normal flora by feeding a faecal suspension from untreated cockroaches resulted in a decrease in numbers ofSalmonellaexcreted, but did not result in their elimination. Carcasses of infected cockroaches retained viableSalmonellafor at least 60 dayspost mortem, or 104 days after the infective meal.
A standard technique for the isolation ofSalmonellafrom animal feeds
Authors: Smith P. J.
Published: May 2009

Two trials were carried out by 9 and 47 laboratories to evaluate the reproducibility and sensitivity of a standard technique for the isolation of salmonellas from animal feeding stuffs.

The trials involved the examinations of test samples containing known numbers of salmonellas by a buffered peptone water pre-enrichment technique. Statistical analysis of the results of the trials showed that the method was capable of detecting salmonellas in most probable numbers as low as 2·3 per 100 g and that no significant differences in performance were observed between laboratories.

The standard technique described is recommended for the examination of animal feed and conforms to international recommendations.
A hospital epidemic caused by a gentamicin-resistantKlebsiella aerogenes
Authors: Curie Kathleen , Speller D. C. E. , Simpson Rosemary A. , Stephens Mary , Cooke P. I.
Published: May 2009

In the 15 months, February 1976 to April 1977, more than 241 patients became colonized with a strain ofKlebsiella aerogenes, capsular serotype K2, resistant to most antibiotics. Urinary tract infection was the most common clinical manifestation but bacteraemia and, occasionally, infections of other sites were encountered. The main reservoir of the epidemic klebsiella was the gut, urine and skin of colonized patients. Gut carriage among staff was very uncommon. The most susceptible patients were elderly males, with debilitating illnesses and urinary tract abnormalities, especially if they were catheterized or receiving antibiotics. Likely vehicles for spread were the hands of staff, and contaminated bedpans and urinals. Control measures were directed at these factors. At the end of April 1977 no new cases had occurred for 3 months in the ward in which the outbreak began, and which had been the main focus of infection, and only 5 patients in the affected hospitals were known to be colonized by the epidemic klebsiella.
Bacterial contamination in a modern operating suite. 3. Importance of floor contamination as a source of airborne bacteria
Authors: Hambraeus A. , Bengtsson S. , Laurell G.
Published: May 2009

The redispersal factor for bacteria-carrying particles from a contaminated floor was determined after mopping, blowing and walking activity. Walking gave the highest redispersal factor, 3·5×10−3 m−1, which was three times higher than for blowing and 17 times higher than for mopping. The mean die-away rate for the bacteria-carrying particles used was 1·9/h without ventilation and 14·3/h with ventilation. It was calculated that in the operating rooms less than 15% of the bacteria found in the air were redispersed floor bacteria.
The behaviour of f2 coliphage in activated sludge treatment
Authors: Balluz S. A. , Butler M. , Jones H. H.
Published: May 2009

A model activated sludge treatment plant was used which was functionally very similar to a full-scale plant. It was inoculated with f2 coliphage and the titres of virus in the influent, the mixed liquor and the effluent were monitored regularly. The distribution of the virus in the solids and liquid fractions of the mixed liquor was in the ratio of 18:82 and 20–4 % of the influent virus was recovered in the effluent. After inoculation was stopped the titre of virus in the solids fraction of the mixed liquor remained high and unaltered for up to 70 h, whereas the value for effluent reverted to the low background titre originally present. These results are discussed in relation to those reported for poliovirus and it is concluded that f2 coliphage is not a suitable model for studies of the behaviour of human enteroviruses.
Excess mortality from influenza in a large urban population, Rome, Italy, 1956–76
Authors: Ragona G. , Giunchi G. , Rocchi G. , Muzzi A. , De Felici A.
Published: May 2009

Influenza activity was studied in the Rome population from 1956 to 1976 by analysis of mortality from respiratory causes and from all causes. During cold weather months, type A influenza virus was associated, as a rule, with epidemic excess deaths at two year intervals while type B virus was prevalent twice during epidemic excess mortality periods. Excess absenteeism from work and virus isolation data were also compared with epidemic excess mortality during four consecutive years. The evidence obtained indicated that influenza virus isolation alone does not represent a reliable index of epidemic influenza activity in this population. The proportion of deaths attributed to respiratory causes consistently increased in every epidemic, the most pronounced increases occurring during large epidemics. The break-down by age of deaths from respiratory causes in the course of two epidemic periods showed that the percentage distribution of deaths was essentially the same as in non-epidemic periods. This evidence indicates that the same factors influencing the age-related distribution of mortality from respiratory causes during non-epidemic periods, probably affect the fatal outcome of influenza during epidemics.
Detection of airborne polyoma virus
Authors: McGarrity Gerard J. , Dion Arnold S.
Published: May 2009

Polyoma virus was recovered from the air of an animal laboratory housing mice infected with the virus. Air samples were obtained by means of a high volume air sampler and further concentrated by high speed centrifugation. Total concentration of the air samples was 7·5 × 107. Assay for polyoma virus was by mouse antibody production tests. Airborne polyoma virus was detected in four of six samples.
Serum antibody to poliovirus in patients in a mental deficiency hospital, with particular reference to Down's syndrome
Authors: McKay Eric , Hems Gordon , Massie Alexander , Moffat Margaret A. J. , Phillips Kathleen McL.
Published: May 2009

Neutralization tests for poliovirus antibodies were carried out on 74 patients in an adult mental deficiency hospital: 37 patients with Down's syndrome and 37 non- Down's mental defectives. The distribution of antibody titres to poliovirus types 1, 2 and 3 did not differ significantly between the two groups. Most patients had antibody to at least one poliovirus typebut less than a third had antibodies at a titre of 1/8 or greater to all three types. The low level of poliovirus immunity in this population may be of epidemiological importance.
Salmonellosis in wild birds feeding at sewage treatment works
Authors: Plant C. W.
Published: May 2009

Between June 1976 and August 1977 faeces were collected from 599 wild British birds caught during ringing operations at two sewage treatment works in south-east England. Samples were incubated with selenite-F broth to detect the presence of Salmonella. Salm. anatum was isolated from one bird, a Dunnock Prunella modularis an incidence of O.17 % of the total birds examined and 3.23 % of the Dunnocks. Comparisons are drawn with previously reported studies and it is suggested that sewage treatment works play little part in the transmission of Salmonella infections to wild birds feeding there.
The relative effectiveness of commonly used disinfectants in inactivation of echovirus 11
Authors: Drulak Murray , Wallbank Alfred M. , Lebtag Ingrid
Published: May 2009

Echovirus 11 in the presence of fetal calf serum was exposed to six commonly used disinfectants for times of 10, 20 and 30 s. At the end of such exposure times, skim milk neutralized disinfectant activity and residual virus was assayed using the plaque technique. The six disinfectants studied were Javex, sodium hydroxide, ethanol, Wescodyne, One Stroke Ves-Phene, and Sonacide. Although 0·25% (w/v) sodium hydroxide and 95% (v/v) ethanol were equally virucidal and significantly more so than the other four disinfectants, causing 106reduction in 20 s, they may not be practical to use in many instances. Javex at a dilution of 1/50 (1200 parts/106chlorine) proved to be virucidal causing 103·5reduction of echovirus 11 in 30 s. Wescodyne (1/50) and undiluted Sonacide were relatively ineffective causing 10 reduction or less of echovirus 11 in 30 s. One Stroke Ves-Phene (1/50) was ineffective causing no significant inactivation in 30 s.
Microneutralization tests for serological typing and subtyping of foot-and-mouth disease virus strains
Authors: Rweyemamu M. M. , Booth J. C. , Head Morwen , Pay T. W. F.
Published: May 2009

A microneutralization test for serotyping of FMD viruses is described. It is based on earlier observations by Booth, Rweyemamu & Pay (1978) that dose-response relationships in quantal microneutralizations often deviated from linearity. The typing test described therefore utilizes undiluted virus preparations. In about 90% of samples a positive typing was obtained in contrast with about 50% for the complement fixation test. The test was also found to be susceptible to minimal quantities of heterotypic viral contamination.

For strain differentiation the microneutralization test was carried out as a checkerboard test. When compared with the complement fixation test it was found to be more specific. The necessity to utilize virus-neutralization test systems for comparing (FMD) virus strains particularly for the purpose of vaccine selection is emphasized. The two dimensional microneutralization test has been applied to a study of comparing FMDV vaccine strains for Europe, South America, the Middle East and East Africa.
Differentiation ofMycoplasma mycoidessubsp.mycoidesfrom certain closely related caprine mycoplasmas by mycoplasmaemia and cross-protection tests in mice
Authors: Hooker J. M. , Smith G. R. , Milligan R. A.
Published: May 2009

In recent years, mycoplasma taxonomists have found that numerous mycoplasma strains from goats are serologically indistinguishable fromMycoplasma mycoidessubsp.mycoides, the causative agent of contagious bovine pleuropneumonia (CBPP), by routinely used tests, e.g. the metabolism-and growth-inhibition tests. As a result, such organisms are now openly referred to asM. mycoidessubsp.mycoides.

Seven of these so-calledM. mycoidessubsp.mycoidesstrains from goats were compared with two strains ofM. mycoidessubsp.mycoidesfrom CBPP, and with one strain ofM. mycoidessubsp.capri, by means of two in-vivo tests, namely, (1) a test of the ability of each strain, injected intraperitoneally into mice, to produce mycoplasmaemia, and (2) a cross-protection test in mice. Of the seven strains, only one (‘O goat’) was indistinguishable from genuineM. mycoidessubsp.mycoides; it also had small colonies resembling those of genuineM. mycoidessubsp.mycoides. The other six were easily distinguished from genuineM. mycoidessubsp.mycoides, and they produced large colonies. These six strains and others like them should no longer be given a name that fails to distinguish them from the causative agent of CBPP.

Cross-protection tests showed that the seven goat strains referred to above differed fromM. mycoidessubsp.capri.
A survey of trimethoprim resistance in the enteric bacterial flora of farm animals
Authors: West B. , White G.
Published: May 2009

For 29 months the Veterinary Investigation Centres, covering the whole of Great Britain, forwarded trimethoprim-resistant gram negative enteric bacteria to the Wellcome Research Laboratories. These were examined for degree of resistance, presence and type of R factors. Trimethoprim resistance was found in 0·6 % of the total number of strains examined by the Veterinary Investigation Centres. Trimethoprim R factors were demonstrated in one quarter of the resistant strains, and R factors were found in two strains ofSalmonella typhimurium. It was concluded that while the incidence of trimethoprim resistance revealed by the survey gave no cause for alarm, the detection of resistant strains, and particularly R factors, indicated that the drug should continue to be used only for specific therapeutic purposes.
Investigation of cross-infection in isolation wards of different design
Authors: Mckendrick G. D. W. , Emond R. T. D.
Published: May 2009

A survey was conducted in seven hospitals to assess the risk of cross-infection with the highly infectious air-borne diseases, varicella-zoster and measles, in isolation wards of different design. Existing wards and isolation techniques were found to afford a high degree of protection, but there was considerable variation in the incidence of cross-infection related to ward structure, ward practice and the availability of trained staff. Recommendations are made for the design of new isolation wards and for safe practice.
The preparation of simulated water samples for the purpose of bacteriological quality control
Authors: Gray R. D. , Lowe G. H.
Published: May 2009

As part of the bacteriological quality control programme of the Public Health Laboratory Service, we were asked to investigate the possibility of providing simulated water samples for distribution to the laboratories. For this purpose it was necessary to find some means whereby suspensions of coliform organisms and Escherichia coli could be kept relatively stable in number at room temperature for a period of 7–10 days. This, it was finally found, was best achieved by adding selected strains of the organisms to improved formate lactose glutamate medium (Gray, 1964) without the lactose but with added boric acid to a final concentration of 1·8%.

The procedures adopted in the successful quality control programme are described.
Observations on environmental contamination in a microbiological laboratory
Authors: Harvey R. W. S. , Price T. H. , Joynson D. H. M.
Published: May 2009

Contamination of a laboratory environment with pathogenic or non-pathogenic micro-organisms may be relevant to safety of technicians and quality of technical performance. Two widely separated incidents in 1968 and 1974 initiated a study of aspects of the laboratory environment. Water-baths, water of syneresis and portions of salmonella cultures spurting out of the sterilizing flame were examined. The water of water-baths was shown to be contaminated from the fluid cultures incubated in them. This raised questions of potential cross-contamination and reporting of false positives. Water of syneresis was sometimes contaminated with salmonellas. A few quantitative counts were made. The range of counts varied between 16 salmonellas per ml. and 13,000,000 salmonellas per ml. Five hundred portions of salmonella cultures and 571 portions of Shigella sonnei cultures which had spurted from the sterilizing flame were examined. All these samples failed to grow salmonellas or shigellas.

Precautions necessary to avoid environmental contamination are briefly discussed.
Point and interval estimation in the combination of bioassay results
Authors: Armitage P. , Bennett B. M. , Finney D. J.
Published: May 2009

A procedure for combining evidence from different biological assays is shown to be equivalent both to generalized least-squares and to maximum-likelihood estimation. By appropriate nesting of hypotheses, the likelihood function can be used to test the agreement between the assays and to obtain probability limits for the combined estimate of potency. The properties of these limits are examined, with particular reference to the situation, unusual but not impossible in practice, in which the values of relative potency that they define consist of several disjoint segments instead of a single interval. The connexion with general theory of estimating linear functional relations is pointed out.
The response to oral poliovaccine in persons aged 16–18 years
Authors: Smith J. W. G. , Lee J. A. , Fletcher W. B. , Morris C. A. , Parker D. A. , Yetts Risha , Magrath D. I. , Perkins F. T.
Published: May 2009

Serum neutralizing antibodies to polioviruses were titrated in serum samples from 182 police cadets aged 16–18 years before and, in 168 of the cadets, 6 weeks after vaccination with a single dose of oral polio vaccine (OPV). Faecal excretion of poliovirus was also followed. Vaccination histories were obtained and confirmed whenever possible.

Pre-vaccination antibody could not be detected against type 1 in 9·3% cadets, against type 2 in 2·7% and against type 3 in 7·7%. Absence of antibody to at least one virus type was found in 14·3 % of the cadets.

In 93 cadets in whom vaccination histories could be confirmed 40 had received only inactivated polio vaccine (IPV) previously; of these 23% lacked antibody to at least one virus type, and they had less intestinal immunity to a challenge dose of OPV than those previously given OPV. Only two of the cadets known to have had OPV were non-immune – both had received a single dose following full courses of IPV. However, cadets who had received OPV had their last dose of vaccine more recently (average 4.6 years) than those who had received only IPV (all 12 years or more).

The serum antibody response to a single booster dose of OPV, and the faecal excretion of each type of virus after vaccination, showed an inverse relation to the corresponding pre-vaccination antibody concentration. A single dose of OPV did not reliably boost the immunity of those who possessed adequate immunity, and a failure to respond was also observed in a proportion of the cadets with no detectable antibody, mostly in the case of type 3 antibody and particularly if antibody to types 1 or 2 virus was also absent. No evidence was obtained that intestinal immunity could be expected in the absence of detectable circulating antibody.

The reasons for the absence of a serological response to OPV in some subjects are discussed and consideration is given to the practical significance of the findings. It is suggested that reinforcement of polio immunity at school-leaving is important, particularly at the present time when many of those aged 16–18 years will have been vaccinated only with IPV. A single does of OPV is not ideal for this purpose, not only because a small proportion of persons are liable to be left unprotected, but also because failure to produce a reliable boost in persons with adequate immunity at the time of vaccination gives rise to the possibility that they may become susceptible later in adult life.
The serotypes ofBordetella pertussisisolated in Great Britain between 1941 and 1968 and a comparison with the serotypes observed in other countries over this period
Authors: Bronne–Shanbury Caroline J. , Miller Delphine , Standfast A. F. B.
Published: May 2009

Classification, by agglutinogens, of 634 isolates ofBordetella pertussiscollected from 1941 to 1968 in Great Britain demonstrated that a change from a predominantly 1,2,0,4 serotype (75% of those examined during 1941–4) to a predominantly 1,0,3,0 serotype (73% of those examined during 1966–8) occurred sometime after 1953. Furthermore, evidence from the examination of isolates collected between 1941 and 1953 suggests that the change may have been gradual. Isolates of serotype 1,2,3,4 made up 20–30% of the total of our cross-country selection for the periods 1941–4, 1946–9, 1950–3 and 1966–8, but over shorter periods in individual areas the percentage varied from negligible to as high as half of those isolated. Results from other countries show a similar drift towards a 1,0,3 serotype but more often from a 1,2,3 than from 1,2,0 serotype.

The value, in epidemiological studies, of extended information obtained by monospecific typing sera to all six, rather than only two or three agglutinogens, and confirmation of the results by agglutinin production is demonstrated: for instance not all 1,0,3 isolates were identical.
Growth of foot-and-mouth disease virus in the upper respiratory tract of non-immunized, vaccinated, and recovered cattle after intranasal inoculation
Authors: McVicar J. W. , Sutmoller P.
Published: May 2009

‘Mention of a trademark or a proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture, and does not imply its approval to the exclusion of other products that may also be suitable.’

Non-immunized, vaccinated, and recovered cattle were inoculated intranasally with various doses of foot-and-mouth disease virus. Samples of oesophageal-pharyngeal (OP) fluid were taken periodically for up to 7 days after inoculation and virus titres of these samples were plotted as pharyngeal virus growth curves.

In non-immunized cattle, the length of the lag period and of the growth period were inversely proportional to the dose of virus given. Maximum titres were observed when clinical signs were first detected. Three of the 10 cattle studied had virus growth rates that were lower than rates of others given the same dose of virus, and clinical signs appeared later than expected in these three cattle.

Cattle vaccinated with an inactivated virus oil-adjuvant vaccine had pharyngeal virus growth curves that were similar to those obtained from non-immunized cattle for 30 h. after inoculation. Titres of virus in OP fluid samples taken 2–7 days after inoculation were substantially lower in cattle with a high pre-exposure serum mouse protection index than titres from partly-immunized or non-immunized cattle.

Nine of 14 recovered cattle had detectable but reduced virus growth after intranasal inoculation with homologous virus. Five recovered cattle inoculated with heterologous virus reacted similarly to non-immunized animals.
Effect of various milk feeds on numbers ofEscherichia coliandBifidobacteriumin the stools of new-born infants
Authors: Hewitt J. H. , Rigby Janet
Published: May 2009

Escherichia coliwas found in a similar proportion of stool specimens from infants who were breast-fed and from others fed on three different artificial-milk preparations. WhenE. coliwas present its mean colony count in the stools of breast-fed infants was within the range of the mean counts for infants receiving the artificial-milk feeds.

There was no consistent relation between high counts of bifidobacteria (Lacto-bacillus bifidus) and low counts ofE. coli.This suggests that measures aimed at implanting or stimulating the growth of bifidobacteria in the large intestine of artificially fed infants may not greatly influence theE. colipopulation therein.

The results are discussed in relation to the protection of artificially fed infants fromE. colienteritis.
Urinary infection in children in general practice: a laboratory view
Authors: Maskell R. M. , Pead L. J.
Published: May 2009

Children with urinary infection present at first to their general practitioners; paediatricians to whom they may be referred must assess the validity of the bacteriological diagnosis made at that time. With this in mind an analysis has been made of the laboratory findings in 2204 mid-stream urine specimens from 1586 children between the ages of two and 12 years examined at the request of their general practitioners during the course of one year.

The contamination rate was shown to be low; 8% of the specimens from boys and 19% of those from girls showed definite infection, and the ratio of infections in boys to girls was 1:4. There was a considerable difference in the infecting organisms in the sexes.

Analysis of the reasons for sending the specimens revealed that a high percentage of children who complained of urinary symptoms did not have infection. Of the children complaining of enuresis only there was a significantly greater incidence of infection in girls than in boys.

In the absence of any large studies of urinary infection in domiciliary practice, data from a laboratory which serves many practitioners can contribute to know ledge of the disease.
Decline of maternal antibodies to plague in Norway rats
Authors: Williams James E. , Eisenberg George H. G. , Cavanaugh Dan C.
Published: May 2009

The decline of maternal antibodies to the fraction I antigen ofYersinia pestiswas investigated in newly weanedRattus norvegicusobtained from dams vaccinated with strain EV76(51f) ofY. pestis.IHA titre decreased by 50% each 7.3 days and CF titre declined 50% each 10.0 days in young rats. An analysis of available data indicated that maternal IHA and CF antibodies could persist to 3 months of age. Therefore, positive serologic reactions in youngR. norvegicus, detected in the course of serological surveys, could be the result either of active immunization after exposure to the plague bacillus or of transient passive immunization (i.e. maternal antibody).
Prevalence of antibody to hepatitis B surface antigen among staff in an Edinburgh hospital
Authors: Burrell C. J. , Tonkin R. W. , Proudfoot E. , Leadbetter G. , Cowan P. , Lockerbie L. , Gore S. , Lutz W. , Marmion B. P.
Published: May 2009

Antibody to hepatitis B surface antigen was detected by radioimmunoprecipitation in 74 (5·5%) of 1336 staff members in a large general hospital in Edinburgh, in 14 (2·9%) of 480 volunteer blood donors in the area, and in 12 (6·1%) of 197 pregnant women attending for the first time at the ante-natal clinic in the hospital. Rates of antibody prevalence rose with age in the sample of hospital staff and in that of the blood donors, particularly among males. On the other hand, in the ante-natal patients antibody prevalence declined with age.

The rates in hospital staff were higher than those in blood donors of comparable age and sex, and high titres of antibody were more common in the staff group. However, no association was found between antibody prevalence and a history of clinical hepatitis, blood transfusion, or recognized contact with cases of hepatitis. Staff who had previously worked in an infectious disease hospital did not show increased antibody prevalence, indicating that simple isolation measures have been adequate to minimize exposure to hepatitis B.

No particular prevalence of infection was seen in physicians and surgeons, in the nursing staff, or in workers in clinical diagnostic laboratories, hospital administration or other areas. One group clearly showing increased antibody prevalence was staff currently working, or who had worked, in the Haemodialysis Unit; this correlated with the outbreak of dialysis-associated hepatitis in 1969–70. However, no evidence suggested that significant dissemination of infection had occurred to other defined groups of hospital staff. Elevated rates were also observed in a small sample of kitchen and portering staff, and in obstetric medical and nursing staff; the latter observations indicate a need for further investigation to identify unsuspected exposure to hepatitis B virus.
The susceptibility of Tatera indica, Nesokia indica and Bandicota bengalensis to three anticoagulant rodenticides
Authors: Greaves J. H. , Rehman A. B.
Published: May 2009

Three South-Asian rodent pest species were tested for susceptibility to anticoagulant rodenticides. Wheat flour containing 0·025% warfarin, 0·0375% coumatetralyl or 0·005% difenacoum was fed to 260 Tatera indica, 140 Nesokia indica and 81 Bandicota bengalensis for 1–56 days. Tatera was about as susceptible to anticoagulants as Rattus rattus has been reported to be. Nesokia and Bandicota were extremely variable: though the majority were highly susceptible, the slopes of the dose-mortality curves were close to zero. The difenacoum diet appeared to be more toxic than the warfarin diet to all three species, but less toxic than the coumatetralyl diet to Tatera and Nesokia. All of the anticoagulants were eventually lethal to all of the animals tested.
Bacteriostasis of Escherichia coli by milk: I. Colonization of breast-fed infants by milk resistant organisms
Authors: Dolby Jean M. , Honour Pauline , Valman H. B.
Published: May 2009

Human milk has a bacteriostatic effect on Escherichia coli in vitro. The milks of 40 mothers were tested for this effect against E. coli isolated from their stools, from those of their own babies, and from those of babies not breast-fed. The milks had a direct bacteriostatic effect, not dependent on complement, on some but not all the strains of E. coli. Breast-fed babies receiving supplementary bottle feeds were colonized with milk-resistant strains, whereas bottle-fed babies and, surprisingly, babies completely breast-fed were colonized equally with milk-sensitive and milk-resistant strains, as were the mothers. These results suggest that the bacteriostatic effect of human milk, demonstrable in vitro does sometimes operate in vivo.

The antibacterial activity of human milk is not influenced by the O, H or K antigens of E. coli and is effective against other Gram-negative organisms, e.g. Salmonella, Klebsiella, Proteus.
Epidemiological analysis of factors influencing rate of progress inEchinococcus granulosuscontrol in New Zealand
Authors: Burridge M. J. , Schwabe C. W.
Published: May 2009

The factors influencing the rate of progress inEchinococcus granulosuscontrol in New Zealand were analysed by hydatid control area using stepwise multiple regression techniques. The results indicated that the rate of progress was related positively to initialE. granulosusprevalence in dogs and the efficiency with which local authorities implemented national control policy, and negatively to the Maori proportion in the local population and the number of dogs per owner. Problems in analysis of the New Zealand data are discussed and improved methods of monitoring progress in hydatid disease control programmes are described.
The persistence of poliovirus in activated sludge treatment
Authors: Balluz S. A. , Jones H. H. , Butler M.
Published: May 2009

A model activated sludge treatment plant was used which was functionally very similar to a full scale plant. It was inoculated with poliovirus either continuously or with a single dose and the amounts of virus in the influent, mixed liquor and effluent were monitored regularly. The distribution of the virus in the liquid and solid phases of the mixed liquor was very unequal with about 85% of the virus associated with the suspended solids fraction. Only small amounts of virus were recovered from the effluent and after inoculation was stopped virus rapidly became indetectable. The efficiency of the plant with regard to removal of virus was closely related to its capacity to remove suspended solids and the adsorption of virus to solids and its inactivation is briefly discussed.
The prevalence and epidemiology of toxoplasmosis in Ontario
Authors: Tizard Ian R. , Chauhan S. S. , Lai C. H.
Published: May 2009

The results of testing 7060 human serum specimens obtained in the Province of Ontario, Canada, were analysed for the presence of antibodies toToxoplasma gondii.Of these samples 38% were serologically positive at a titre of 1/16 or greater. The age-specific rates climbed from 2·7% in infants between 6 months and 1 year of age, to about 50% in individuals aged 25 years or over. Variations in prevalence were noted between different areas within the province and evidence is put forward to show that an inverse relation exists between urban size and toxoplasma prevalence. Seasonal and annual variations were not shown to be significant. On the basis of a very small sample of specimens, cat ownership did not appear to cause a significant increase in the risk of acquiring this infection.