Young adult mice were inoculated intravenously with strains JB or Peter C of Mycoplasma pulmonis. A few were inoculated intranasally with strain JB. This strain but not Peter C was isolated for 50 days or more from the urines of more than half of the mice. Those of strains TO, C3H and CBA, but not CFLP, were susceptible. Recovery of mycoplasmas was intermittent and sometimes the numbers isolated varied within individual mice and between mice of a particular strain, ranging from 5 × 101 to <5 × 107 colour-changing units/ml. Fifty serial passes of M. pulmonis, strain JB, in mycoplasmal medium resulted in attenuation, the organisms after inoculation of TO mice not being recovered from the urine and excretion not being stimulated by treating the mice with progesterone. At autopsy, the organisms of early passage were usually but not invariably isolated from the kidneys of mice that had been urinary excretors. About half of the latter had no renal histopathological changes. The others had usually minimal renal perivascular lymphocytic infiltrates but occasionally more widespread inflammatory changes. The findings may have relevance to the spread of mycoplasmal infection within mouse colonies and suggest that an association between such infection and nephritis in other species, including man, should be sought more closely.

The results obtained in these investigations were negative throughout, but perhaps are worth recording as tending to show that the formation of such ‘anti-bodies’ as cytolysins and precipitins is not a necessary reaction on the part of any living organism to the presence of foreign cells or substances.

Hantaviruses are endemic in the Balkans, particularly in Serbia, where sporadic cases and/or outbreaks of hantaviral human disease have been reported repeatedly, and evidenced serologically. Here, we present genetic detection of Dobrava-Belgrade virus (DOBV) hantaviral sequences in wild rodents trapped in central Serbia. All the animals were pre-screened serologically by indirect immunofluorescence (IF) test and only those with a positive finding of hantaviral antigens were further tested by polymerase chain reaction. Of the total of 104 trapped animals, 20 were found to be IF positive and of those three were positive for hantaviral RNA: one Microtus arvalis for Tula virus, and one each of Apodemus agrarius and Glis glis for DOBV. Phylogenetic analysis of the obtained sequences implies putative DOBV spillover infection of A. agrarius and G. glis from Apodemus flavicollis. However, future investigations should help to identify the most common natural host and geographical distribution of DOBV in its reservoir hosts in Serbia.

Among 469 US military veterans with an Escherichia coli clinical isolate (2012–2013), we explored healthcare and non-healthcare risk factors for having E. coli sequence type 131 and its H30 subclone (ST131-H30). Overall, 66 (14%) isolates were ST131; 51 (77%) of these were ST131-H30. After adjustment for healthcare-associated factors, ST131 remained positively associated with medical lines and nursing home residence. After adjustment for environmental factors, ST131 remained associated with wild animal contact (positive), meat consumption (negative) and pet cat exposure (negative). Thus, ST131 was associated predominantly with healthcare-associated exposures, while non-ST131 E. coli were associated with some environmental exposures.

The last 30 years have been changes in emphasis in the study of streptococci and streptococcal diseases. Earlier work concentrated mainly on the sources and methods of cross-infection and descriptive epidemiology of Streptococcus pyogenes in its major manifestations of respiratory, cutaneous and invasive infection and in the complications of rheumatic fever (RF), scarlet fever (SF) and post-streptococcal glomerulonephritis (PSGN).

The single radial haemolysis test is conveniently practical and economical and promises to have wide applicability in the study of influenza antibodies in human populations. It can also be adapted for preliminary examination of new virus isolates during epidemics.

Using this test a rather higher proportion of the population in the Highland Region of Scotland was found to possess antibody to a recent epidemic strain of influenza (A/Scotland/74) than was the case in the south of England. Antibody was detected and apparently evenly spread throughout all but the most remote island communities. Some evidence of the spread of the subsequent variant, A/Victoria/75, was obtained. Most of the school children in our study had high antibody titres to recent strains but the proportion with high antibody titres to these strains declined speedily from the age of 17 years onwards.

The main Neisseria meningitidis adhesion molecules, type IV pili (Tfp) and Neisseria adhesion A (NadA), play important roles in the pathogenesis of invasive meningococcal disease. PilE is the major Tfp subunit. In this study, the prevalence and genetic diversity of pilE and nadA were investigated in the prevalent serogroups and clonal complexes (CC) of N. meningitidis isolated in China. All serogroup A strains belonging to CC1 and CC5 and all CC11 serogroup W135 strains were clustered into class II PilE clades. All serogroup C and most of serogroup B isolates except CC8 and ST5642 were class I PilE clades. Class II pilE sequences were highly conserved. All isolates belonging to class I PilE isolates were nadA negative. However, nadA-positive strains were exclusively found in CC5 and CC11 isolates (class II PilE). This study showed that PilE and NadA may be related to epidemic or endemic meningococcal disease.

The chief object of the research here recorded was to try and bring this Colony into line with other plague centres from which valuable figures on this subject have already been recorded.

At present, there is scarce evidence about the burden associated with the isolation of COVID-19 patients. We aimed to assess the differences between COVID-19 and other influenza-like illnesses (ILIs) in disease burden brought by isolation. We conducted an online survey of 302 respondents who had COVID-19 or other ILIs and compared the burden of isolation due to sickness with one-to-one propensity score matching. The primary outcomes are the duration and productivity losses associated with isolation, the secondary outcome is the health-related quality of life (HRQoL) valuation on the day of the survey. Acute symptoms of outpatient COVID-19 and other ILIs lasted 17 (interquartile range (IQR) 9–32) and 7 (IQR 4–10) days, respectively. The length of isolation due to COVID-19 was 18 (IQR 10–33) days and that due to other ILIs was 7 (IQR 4–11) days, respectively. The monetary productivity loss of isolation due to COVID-19 was 1424.3 (IQR 825.6–2545.5) USD and that due to other ILIs was 606.1 (IQR 297.0–1090.9) USD, respectively. HRQoL at the time of the survey was lower in the COVID-19 group than in the ‘other ILIs’ group (0.89 and 0.96, P = 0.001). COVID-19 infection imposes a substantial disease burden, even in patients with non-severe disease. This burden is larger for COVID-19 than other ILIs, mainly because the required isolation period is longer.

The biological characters, and pathological effects in animal inoculation, of a strain of B. whitmori from Saigon are described. It is the most virulent strain of the organism from a human source that has so far been encountered. The case from which the organism was recovered was an example of the septicaemic from of melioidosis.

In a previous communication (1906) it was shown by Bulloch and Craw that the Doulton “white filter” prevented the direct transimmission of micro-organisms, and that the filtrates from highly contaminated waters were germ free until sufficient time had been given for the bacteria to grow through the filter mass. It was demonstrated, in fact, that the Doulton filter was at least as efficient in the retention of micro-organisms as the best material on the market, viz. the Pasteur-Chamberland filter, and excelled the latter in its rate of filtration. It was pointed out that, with the possible exception of Kieselguhr, filters, only porcelain bougies could be relied upon to prevent direct transmission of germs. During the past year we have tested the relative efficiency of porcelain and Kieselguhr filters, in particular the Doulton porcelain filter and the Berkefeld Kieselguhr filter. A few samples of the Slack and Brownlow filter (sand and porcelain mixture?) were also tested.

Typing techniques are laboratory methods used in outbreak management to investigate the degree to which microbes found within an outbreak are related. Knowledge about relational patterns between microbes benefits outbreak management, but inevitably also tells us something about the relational patterns of the people hosting them. Since the technique is often used without explicit consent of all individuals involved, this may raise ethical questions. The aim of this study was to unravel the complex ethical deliberation of professionals over the use of such techniques. We organised group discussions (n = 3) with Dutch outbreak managers (n = 23). The topic list was based on previously identified ethical issues and discussions were analysed for recurrent themes. We found that outbreak managers first and foremost reflect on the balance of individual harm with public health benefit. This key question was approached by way of discussing four more specific ethical themes: (1) justification of governmental intervention, (2) responsibility to prevent infections, (3) scientific uncertainty and (4) legal consequences. The themes found in this study, rephrased into accessible questions, represent the shared ethical understanding of professionals and can help to articulate the ethical dimensions of using molecular science in response to infectious disease outbreaks.

Under warm weather conditions, contamination from milking machine rubber parts can be effectively controlled by simple, practicable methods. Milk drawn by machines so treated is equal in sanitary quality to that produced by careful hand milking.

The chloramine-brine treatment proved to be quite as effective as the hot water treatment in controlling bacterial contamination, while superior from the standpoint of economy and simplicity.

The stock diet for rats and mice, diet 41 cubed, can be rendered sterile to broth by autoclaving at 15 lb./sq. in. for 20 min. without impairment of the nutritive value for breeding mice.

In former reports by us, considerable attention was devoted to a study of the number and nature of the cellular elements in milk.We found that cells, sometimes in enormous numbers, are present in all milk (cow, goat, ass, man), that considerable variations in number occur without apparent cause, and that the presence of the slighter forms of non-suppurative mastitis does not seem to influence definitely the number of these cells.

Cryptosporidium is a zoonotic protozoan parasite with public health importance worldwide. The objectives of this study were to (1) conduct a meta-analysis of published literature for oocyst shedding and diarrhoea outcomes, and (2) develop recommendations for standardization of experimental dose–response studies. Results showed that for the outcome of oocyst shedding in faeces, the covariates ‘experimental species’, ‘immunosuppression’, ‘oocyst dose’ and ‘oocyst dose’ × ‘age’ were all significant (P ⩽ 0·05). This study suggests that exposing mice, piglets, or ruminants, and using immunosuppressed experimental hosts, is more likely to result in oocyst shedding. For the outcome of diarrhoea in experimentally infected animal species, the key covariates ‘experimental species’, ‘age’ and ‘immunosuppression’ were significant (P ⩽ 0·2). Therefore, based on the results of this meta-analysis, these variables should be carefully reported and considered when designing experimental dose–response studies. Additionally, detection of possible publication bias highlights the need to publish additional studies that convey statistically non-significant as well as significant results in the future.

The principle of the aerosol centrifuge is described, and an elementary mathematicaltreatment is given.

The relations between the behaviour of the centrifuge and its dimensions, speed and airflow have been tested experimentally on three machines. It is shown that the mathe-matical formulae given are an adequate basis for design.

Various applications are mentioned.

Shigella flexneri 4a caused sustained outbreaks in a large long-stay psychiatric centre, Taiwan, 2001–2006. Trimethoprim-sulphamethoxazole (SXT) prophylaxis was administered in 2004. We recovered 108 S. flexneri 4a isolates from 83 symptomatic (including one caregiver) and 12 asymptomatic subjects (11 contacts, one caregiver). The isolates were classified into eight antibiogram types and 15 genotypes (six clusters) by using antimicrobial susceptibility testing and pulsed-field gel electrophoresis of NotI-digested DNA, respectively. These characteristics altered significantly after SXT prophylaxis (P < 0·05), with concomitant emergence of SXT-resistant isolates in two antibiogram types. P01 (n = 71), the predominant epidemic genotype, caused infection in two caregivers and five patients under their care; two P01 isolates were recovered from the same patient 6 months apart. These results indicate the importance of sustained person-to-person transmission of S. flexneri 4a by long-term convalescent, asymptomatic or caregiver carriers, and support the emergence of SXT-resistant strains following selective pressure by SXT prophylaxis.

In Canada, vaccination policies against the 2009 influenza H1N1 pandemic (H1N1pdm09) were modified at different times during the autumn wave. We hypothesized that ethnicity and place of residence influenced the odds of vaccination. To test this hypothesis, we used vaccination databases for the entire province of Manitoba, and obtained the age distribution of vaccination for First Nations (FN) and non-First Nations (non-FN) populations. We used regression analysis to determine the effect of ethnicity and location of residence on odds of vaccination. We found that individuals with FN identity were over 2.8 times [95% confidence interval (CI) 2.79–2.87] more likely to receive vaccination compared to non-FN individuals. For the FN populations, on-reserve residency was associated with 5.15-fold (95% CI 5.00–5.30) higher odds of vaccination compared to off-reserve residency. Our study highlights the importance of demographic and geographical variables in developing strategies for vaccine prioritization.

The numbers and types of bacteria in thirty-nine samples of dried whale meat of the 1946–7 and 1947–8 Antarctic whaling seasons have been investigated.

The total number of bacteria was low for this type of product and there were about equal numbers of clostridia and aerobic bacteria.

A detailed examination of the clostridia present showed that they were of types commonly found in material from mammalian sources.

No Clostridium pathogenic to the mouse was found, although some cultures on prolonged incubation killed mice by ammonia poisoning. Ammonia poisoning was produced by injection of cultures and never by oral administration.