Pour thousand two hundred and forty six samples of retail processed food were examined for the presence of Escherichia coli. Overall 12% of samples contained this organism, cakes and confectionery being more frequently contaminated (28%) than meat and meat based products (9%). Contamination was more frequent in the summer months than in the colder weather and 27% of the contaminated foods contained > 103E. coli/g. E. coli from meat and meat based products were more commonly resistant to one or more antibiotics (14%) than were confectionery strains (1%). The significance of these findings in relation to the E. coli population of the human bowel is discussed.

The efficacy of three anticoagulant rodenticides for use against the Indian field mouse, Mus booduga, was evaluated in the laboratory. The poisons, namely warfarin, bromadiolone and brodifacoum, were all found to be toxic enough at the concentrations normally used against other commensal and field rodents. With brodifacoum (0·00125%), bromadiolone (0·005%) and warfarin (0·025%), 83% of the animals died respectively after 1, 1 and 6 days' feeding. It is suggested that brodifacoum and bromadiolone might be more economical than warfarin for use in practical rodent control.

A report is made of a total of 438 simultaneous blood serum and milk ring tests, and an attempt made to evaluate the milk ring test as a diagnostic aid in individual animals.

The ring test has been used to test the bulk milk from some 370 herds providing the greater part of the raw milk supply for Edinburgh.

The incidence of viable Br. abortus in raw milk samples taken in the Edinburgh area has been studied together with the ring test reaction of such samples.

The survey has shown that:

(1) The ring test is correct in some 93 % of cases in detecting cows whose blood serum will be found positive to the brucella agglutination test.

(2) The ring test, if carefully carried out, is a simple time-saving and accurate screening test for detecting herds possibly infected with brucella.

(3) A high proportion of herd milks (53 %) giving a positive reaction to the ring test is disclosed, and the probable effect of vaccination with strain 19 in giving rise to this figure is noted.

(4) The relatively high incidence (at least 10·5%) of Br. abortus in Edinburgh milk supplies is noted.

Thanks are tendered to Dr Bruhn of the Veterinary School, and Dr Bendtsen, Veterinary State Serum Institute, both of Copenhagen and to Dr Stableforth of the Ministry of Agriculture and Fisheries Laboratory at Weybridge, for providing samples of stained antigen. Thanks are also due to the Bacteriology Department, Edinburgh University, for providing material from guinea-pigs and for relevant information; to J. Norval, Esq., M.R.C.V.S., for permission to obtain samples from the slaughterhouse, and also to the dairies and farmers who granted facilities for taking samples and to Miss Elma Chapman for assistance in the laboratory studies and in taking samples.

The aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producing Escherichia coli (STEC) and Campylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n = 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) for E. coli serotypes O26, O103, O111, O145 and O157. The number of samples positive for E. coli O26 (30/72) was high compared to E. coli O103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). Eighteen E. coli O26 and 53 C. jejuni isolates were recovered from samples by bacterial culture. E. coli O26 and C. jejuni isolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. All E. coli O26 isolates could be divided into four clusters and the results indicated that E. coli O26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types of C. jejuni isolated from the cattle and 22 from water. An analysis of the population structure of C. jejuni isolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.

The isolation of Fusobacterium necrophorum present in small numbers in heavily contaminated material such as faeces or soil is hampered by the lack of an efficient selective medium and by the high minimum infective dose of the organism. A sensitive method for the detection and isolation of faecal strains of F. necrophorum type A was based on the subcutaneous injection of faeces, suspended (5% w/v) in broth culture of Actinomyces (Corynebacterium) pyogenes or Staphylococcus aureus to increase fusobacterial infectivity, into mice pretreated with clostridial antitoxins. When necrobacillosis developed F. necrophorum was identified microscopically in tissue from the advancing edge of the lesion and isolated on a partly selective medium.

The enhancement of fusobacterial infectivity produced by A. pyogenes and by S. aureus was high, but the latter was slightly the more efficient, enabling as few as 80 F. necrophorum organisms/g of faeces to be detected.

Use of the method showed that 3 of 16 wallabies had F. necrophorum in their faeces at the time of examination. Numerous epidemiological applications are suggested.

A mineral oil adjuvant failed to enhance or to prolong the somewhat shortlived immunity induced in baboons by trachoma/inclusion conjunctivitis (TRIC) vaccines, and was of little or no value in increasing or prolonging the formation of group complement-fixing (CF) antibody. Vaccines prepared with protamine sulphate or with calcium phosphate were no more immunogenic than the untreated parent suspensions.

Cross tests with aqueous vaccines revealed antigenic differences in the TRIC agents examined, in terms of their ability to protect against conjunctival challenge. Strain MRC–1/OT differed from MRC–17 and from MRC–4, and MRC–187 from MRC–4f.

The four Gambian trachoma agents tested were much less effective than the MRC–4 strain of inclusion conjunctivitis in inducing group CF antibody in baboons. The titre of circulating antibody bore no relation to the state of immunity to conjunctival challenge.

In three baboons given mineral oil adjuvant vaccine and in one given aqueous vaccine the conjunctival responses to subsequent challenge were significantly enhanced. This reaction may be an expression of a hypersensitive state induced by relatively ineffective vaccines; like immunity, it is unrelated to the titre of CF antibody in the serum.

In the present paper we describe the results of further investigations on the life-history of Piroplasma canis in the blood of the dog. In our last paper (x. 1906) we described and figured the movements of the parasite and the mode of multiplication in the dog's blood, and since that time we have confirmed most of our previous observations, and added further facts. The technique of these examinations was fully explained in that paper (p. 604), and it is only necessary to state here that all our later observations on living blood have been made at a temperature of 35°—40°C. The drops of blood were mounted on clean glass slides and cover-glasses kept at this temperature, and were placed as rapidly as possible on the stage of a microscope kept at a similar temperature in a Nuttall's thermostat and examined under a oil immersion lens. In fact we have endeavoured to make our observations in such a manner that the blood should be altered as little as possible.

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.

Two statistical analyses are suggested to compare the success rates in isolating and identifying pathogenic organisms from specimens achieved by different laboratories participating in a quality control scheme. An example is given in which the analyses are applied to 25 laboratories that received 30 simulated specimens.

The mechanism of spread of an epidemic of variola minor (alastrim) occurring in 1956, in Vila Guarani, a semi-rural school district of the City of São Paulo, Brazil, is examined. Cases were grouped according to time and space relationships corresponding to either a household or a school class, as once variola minor was introduced into a household or a school class spread was independent of occurrences in neighbouring social units. The constant occurrence of a single introduction in school classes and households implied that the chance for transmission of the disease outside the homes or the school was very small. The secondary attack rate was higher in households than in school classes. Twenty households with cases had more pre-school children and school children and a lower vaccination level than twenty-two neighbouring households without cases but also including one or more persons who were known to have had personal contacts with patients.

Examination of the chain of contagion clearly shows that spread in the school was directly and indirectly responsible for the majority of cases in the epidemic, for the peak of the epidemic curve and for the extent of topographical spread of the epidemic. This predominant role of the school was accentuated by incomplete preventive measures (vaccination campaign and isolation of patients) applied late in the epidemic and it is attributed to the following facts, (a) There was a single school in the district, and school children were thus concentrated, (b) The school was the only place of the district where persons living in different neighbourhoods had regular, repeated contacts, (c) The great majority of school children had had no previous variola and many had no vaccination scar, (d) The social activities of school children gave them the highest potential as transmitters of variola minor.

The toxic effect of certain products of Pseudomonas aeruginosa on guinea-pig alveolar macrophages has been studied in an attempt to account for the apparent infrequency with which certain strains of this species are associated with respiratory infection. Tests were carried out on strains derived from the respiratory tract, strains from infection at other sites, and strains from the inanimate hospital environment which were believed not to have been responsible for infection (‘environmental’ strains).

Haemolysin, pigments, enzyme-containing fractions, slime and cell-wall fraction all exhibited toxic activity against macrophages in an in vitro system, although for any given strain of Ps. aeruginosa the haemolysin was by far the most potent factor. The activity of this factor against macrophages was directly proportional to its haemolytic activity against human erythrocytes. The haemolysin fractions of environmental strains, which have previously been found to have little activity on erythrocytes, were also less active against macrophages than haemolysin preparations from ‘infective’ strains.

It is therefore postulated that the ability of a strain of Ps. aeruginosa to initiate respiratory infection may be related to the degree of haemolysin production. The activity of other fractions against macrophages is more variable, but they may contribute in different ways to the development of infection once entry into the lung has been achieved.

The study was conducted to determine whether pre-enrichment would increase sensitivity of detecting Streptococcus (Str.) aqalactiae, Staphylococcus (S.) aureus, and mycoplasma in bovine milk. Two procedures were followed, one involving direct inoculation of milk on bovine blood agar, and the other involving preenrichment in broth followed by inoculation on agar. Logistic regression was used to predict the probability of isolation as a function of culture procedure and two additional covariates. the California Mastitis Test (CMT) score of the milk and the type of sample (indicating sample storage temperature and herd mastitis status). A total of 13778 milk samples was cultured for each of the three bacteria. By using results of both direct inoculation and pre-enrichment, the probability of isolation compared to use of direct inoculation only and adjusted for effects of other variables was increased 3·6-fold for Str. agalactiae, 1·6-fold for S. aureus and 1·7- fold for mycoplasma. The probability of isolation for all three bacteria increased as the CMT score increased. For Str. agalactiae, there was a statistical interaction predicting that enrichment improved the odds of isolation more from milk with high CMT scores than from milk with low scores. Results indicate that preenrichment can substantially increase the sensitivity of bacteriological screening of dairy cows for mastitis caused by Str. agalactiae, S. aureus, and mycoplasma.

One thousand, nine hundred and seventy-seven pharmaceutical products used in the home were examined for microbial contamination. Viable micro-organisms were recovered from 14.0% of samples. Medicines used in the home are apparently not exposed to the same opportunities for contamination as those used in hospital.

Susceptibilities to amphotericin B and fluconazole of 628 clinical yeast strains collected from 22 hospitals in Taiwan were determined. A total of 53 isolates (8·4%) were resistant to fluconazole. Each hospital had different resistance rate to fluconazole ranging from 0% to 24%. None of the 186 isolates from eight of the 22 hospitals was resistant to fluconazole. In contrast, isolates from nine of the remaining 14 hospitals had greater than 10% resistance rate to fluconazole. Consistently, 88·9% (8/9) fluconazole-resistant C. albicans isolates were from hospitals having a high resistance rate to fluconazole. The prevalence of various Candida spp. in each hospital was different. A positive association was found between the prevalence of C. tropicalis and the resistance rate to fluconazole for individual hospitals. Although only three isolates (0·5%) were resistant to amphotericin B, a co-resistance to both amphotericin B and fluconazole was observed, which highlights the emerging problem of drug resistance.

The novel coronavirus, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), is the causative agent of the 2020 worldwide coronavirus pandemic. Antibody testing is useful for diagnosing historic infections of a disease in a population. These tests are also a helpful epidemiological tool for predicting how the virus spreads in a community, relating antibody levels to immunity and for assessing herd immunity. In the present study, SARS-CoV-2 viral proteins were recombinantly produced and used to analyse serum from individuals previously exposed, or not, to SARS-CoV-2. The nucleocapsid (Npro) and spike subunit 2 (S2Frag) proteins were identified as highly immunogenic, although responses to the former were generally greater. These two proteins were used to develop two quantitative enzyme-linked immunosorbent assays (ELISAs) that when used in combination resulted in a highly reliable diagnostic test. Npro and S2Frag-ELISAs could detect at least 10% more true positive coronavirus disease-2019 (COVID-19) cases than the commercially available ARCHITECT test (Abbott). Moreover, our quantitative ELISAs also show that specific antibodies to SARS-CoV-2 proteins tend to wane rapidly even in patients who had developed severe disease. As antibody tests complement COVID-19 diagnosis and determine population-level surveillance during this pandemic, the alternative diagnostic we present in this study could play a role in controlling the spread of the virus.

Four groups of sows were inoculated, either once or twice, with O1BFS 1860 foot and mouth disease oil-emulsion vaccine during pregnancy and samples of serum. for analysis, were collected at intervals for > 300 days.

The pregnant sows responded well to vaccination regardless of their state of gestation. Single vaccination produced protective levels of antibody (> 1·53 log10SN50) in 3 out of 4 sows while double vaccination produced protective levels in all 6 sows tested. Anti-FMD IgM antibodies could be detected for 40–60 days after vaccination or revaccination. Anti-FMD IgG antibodies appeared within 10 days of vaccination and persisted, in each sow, for the duration of the study. The anti-FMD IgA response observed was less easy to characterize due to significant animal to animal variation. Although there was no evidence of a fall in the neutralizing antibody titres over one year post vaccination the anti-FMD IgG antibody population did show signs of a change in its heterogenity and avidity.

This report presents the parasitological, bacteriological, mycological and physicochemical data obtained from both surface water and beach sand of a lake used for water sports. These show that the lake is contaminated in both winter and spring by water which overflows from the River Maine, and is self-purified by a mechanism of ‘lagunage’. In summer signs of pollution are at their lowest level although use of the complex is at its peak. Conversely, the amoebic flora, which is independent of the usual criteria of pollution, predominates in summer, and serves as a marker for the need for increased surveillance. The sand of the beaches does not appear to show any infectious hazard. Environmental pressure will doubtless change these data over a period of time, and it is planned to monitor this.

The relative efficiencies of three commercially available dehydrated Rappaport–Vassiliadis media have been compared with a similar medium prepared from individual constituents in our own laboratory. An inoculation ratio of 1 : 100 was found to be optimal for each of the media tested. Laboratory produced RV-medium was significantly better than the three commercial preparations after 24 h incubation. However, when the duration of incubation was extended to 48 h, there was no significant difference in the number of salmonella isolates obtained when using our own RV medium and that produced by Oxoid Ltd and Difco Ltd (P > 0·05). All of these three media were, however, significantly more effective than the medium produced by Lab.M.(P <0·01).

A survey of unopened ice cream, ice cream in use, and ice-cream-scoop water (n=91) was conducted to determine the effect of scoop water hygiene on the microbiological quality of ice cream. An aerobic plate count around 106 c.f.u. ml−1 was the modal value for scoop waters. Unopened ice creams generally had counts around 103–104 c.f.u. ml−1 and this increased by one order of magnitude when in use. Many scoop waters had low coliform counts, but almost half contained >100 c.f.u. ml−1. E. coli was isolated in 18% of ice creams in use, and in 10% of unopened ice creams. S. aureus was not detected in any sample. Statistical analysis showed strong associations between indicator organisms and increased counts in ice cream in use. EC guidelines for indicator organisms in ice cream were exceeded by up to 56% of samples.