A new fast-growing mycobacterium, designated strain QGD101T, was isolated from the sputum of an 84-year-old man suspected of tuberculosis in Wuhan Medical Treatment Center, Hubei, China. This strain was a gram-staining-negative, aerobic, non-spore-forming and catalase-positive bacterium, which was further identified as the NTM by PNB and TCH tests. The moxifloxacin and levofloxacin exhibited strong suppressing function against QGD101T with MIC values of 0.06 and 0.125 µg/ml after drug susceptibility testing of six main antimicrobial agents on mycobacteria. Based on the sequence analysis of 16S rRNA, rpoB, hsp65 and 16S-23S rRNA internal transcribed spacer, the strain QGD101T could not be identified to a species level. Mycobacterium moriokaense ATCC43059T that shared the highest 16S rRNA gene sequence similarity (98%) with strain QGD101T was actually different in genomes average nucleotide identity (78.74%). In addition, the major cellular fatty acids of QGD101T were determined as C18:1ω9c, C16:0 and C18:2ω6c. The DNA G + C content was 64.9% measured by high performance liquid chromatography. Therefore, the phenotypic and genotypic characterisation of this strain led us to the conclusion that it represents a novel species of mycobacteria, for which the name Mycobacterium hubeiense sp. nov. (type strain QGD101T = CCTCCAA 2017003T = KCTC39927T) was proposed. Thus, the results of this study are very significant for the clinical diagnosis of tuberculosis and future personalised medicine.

Serology data are an increasingly important tool in malaria surveillance, especially in low transmission settings where the estimation of parasite-based indicators is often problematic. Existing methods rely on the use of thresholds to identify seropositive individuals and estimate transmission intensity, while making assumptions about the temporal dynamics of malaria transmission that are rarely questioned. Here, we present a novel threshold-free approach for the analysis of malaria serology data which avoids dichotomization of continuous antibody measurements and allows us to model changes in the antibody distribution across age in a more flexible way. The proposed unified mechanistic model combines the properties of reversible catalytic and antibody acquisition models, and allows for temporally varying boosting and seroconversion rates. Additionally, as an alternative to the unified mechanistic model, we also propose an empirical approach to analysis where modelling of the age-dependency is informed by the data rather than biological assumptions. Using serology data from Western Kenya, we demonstrate both the usefulness and limitations of the novel modelling framework.

The chemical changes which occur in the dissolved solids of sewage on discharge into sea-water have been investigated by several workers (see references 1–11). Some observation on the difference of these changes to those occurring in polluted fresh water have been made by Letts and Richards (6,11). In regard to waters whose saline composition is not such as to preclude their admissibility for potable purposes on this account, Liversidge(12) has made a brief communication on the variation in the free and albuminoid ammonia.

The result of bacteriological research indicates that the material infected is probably not large compared to the total amount used, and that in suspected samples of both hair and bristles anthrax bacilli can be isolated either by inoculation of animals or by plate cultivation.

Difficulties are met with in the inoculation of animals owing to the presence of the bacillus of malignant oedema, which, unless special methods are used as shown by Duncan, will often mask the presence of the anthrax bacillus altogether.

In separation by means of agar plates the presence of bacilli very closely resembling anthrax again leads to error. Three types of these bacilli have been met with in hair and bristles; viz.: Bac. A2 or Bac. anthracoides of Bainbridge, possibly the same as Bac. subtilis, the Bac. A1, and Bac. A. The last two do not exactly correspond with any known bacilli, and so far as we know at present are of little importance, but in view of the experiments of Gilruth showing that guinea-pigs, rabbits, and sheep can resist the inoculation of large doses of virulent anthrax bacilli completely, provided these organisms are mixed with a larger quantity of some other organisms which are non-pathogenic to these animals, and that a small amount of immunity to pure anthrax is conferred, it is certain that the presence of these anthrax-like bacilli, evidently closely related to the anthrax bacillus, cannot but be of benefit; and it is possible that further experiments may show that injections of them mixed with cultures of anthrax bacilli of varied virulence may confer a higher degree of immunity than do mixtures of anthrax with other non-pathogenic bacilli, as shown by Gilruth (1904).

Two hundred and fifty clinical strains of Candida albicans and six isolates from a cross-infection outbreak were studied for their ability to assimilate 19 carbohydrates in the API-20C system (API Laboratory Products Ltd., Basingstoke, UK). The assimilation profiles were stable on repeat testing; at intervals in the 72 h duration of the test; and when incubated at different temperatures.

Although not a complete system of biotyping, the API-20C system shows high typability, and fair reproducibility and discrimination, having a limited role in indicating which isolates should be typed by more elaborate methods.

Catheter-related blood-stream infections (CRBSIs) are the most common healthcare-associated blood-stream infections. They can be diagnosed by either semi-quantitative or quantitative methods, which may differ in diagnostic accuracy. A meta-analysis was undertaken to compare the diagnostic accuracy of semi-quantitative and quantitative methods for CRBSI. A systematic search of Medline, Scopus, Cochrane and Embase databases up to January 2020 was performed and subjected to a QUADAS (quality assessment of diagnostic accuracy studies 2) tool to evaluate the risk of bias among studies. The pooled sensitivity and specificity of the methods were determined and heterogeneity was evaluated using the χ2 test and I2. Publication bias was assessed using a Funnel plot and the Egger's test. In total, 45 studies were analysed with data from 11 232 patients. The pooled sensitivity and specificity of semi-quantitative methods were 85% (95% CI 79–90%) and 84% (95% CI 79–88%), respectively; and for quantitative methods were 85% (95% CI 79–90%) and 95% (95% CI 91–97%). Considerable heterogeneity was statistically evident (P < 0.001) by both methods with a correspondingly symmetrical Funnel plot that was confirmed by a non-significant Deek's test. We conclude that both semi-quantitative and quantitative methods are highly useful for screening for CRBSI in patients and display high sensitivity and specificity. Quantitative methods, particularly paired quantitative cultures, had the highest sensitivity and specificity and can be used to identify CRBSI cases with a high degree of certainty.

In resource-limited countries, the lack of widespread screening masks the true situation of COVID-19. We conducted this study to assess SARS-CoV-2 spread by detection of specific antibodies and to determine associated factors. A population-based cross-sectional study was conducted. Subjects were tested for the presence of two antibodies (IgM and IgG) specific to SARS-CoV-2. Data collection was done using a smartphone with the KoboCollect application. Prevalence of antibodies was estimated with 95% confidence intervals. Logistic regression was used to determine factors associated with positive serological test. A total of 9,094 persons were tested in 4,340 households. The mean age was 30.18 ± 18.65 years, 46.5% male. The overall seroprevalence (prevalence, 95% CI) of SARS-CoV-2 antibodies was (48.2% [47.2%–49.2%]). Being vaccinated, having been in contact with a COVID-19 patient, being older than 50 years, living in a union, having secondary education and having tertiary education were factors independently associated with the likelihood of having anti-sars-CoV-2. We estimate in February 2022 that 48% persons had antibodies against the COVID-19 virus, more among those vaccinated. Vaccination intensification in low prevalence departments will reduce the risk of new outbreaks.

In an attempt to determine the frequency of virus infections of the gastrointestinal tract, the duration of virus shedding in faeces and its relation to outbreaks of illness of any kind, faecal samples were collected from children attending a day nursery at a Lisbon institution.

In this study, ten children were surveyed from their enrolment at the nursery, weekly specimens of faeces being collected over a period of 1 year. A total of 459 samples were obtained. In addition four of these children were also followed-up from their first week of life to their enrolment at the nursery, 79 samples being collected during this period.

Viruses were detected in a high percentage (44·4%) of these stools, including strains of oral vaccine polioviruses together with viruses isolated in routine cell cultures and by electron microscopy (EM). These viruses were detected in both healthy and ill babies.

The possible association between viruses isolated in cell cultures or detected by EM and illness was examined and the results show that the asymptomatic excretion of viruses is frequent, particularly in children within this age group.

The investigation of plasmid similarity is an important component in the surveillance of antimicrobial resistance and in the detection of epidemic plasmids. The use of restriction endonucleases in the classification of transferable, multiply-resistant plasmids from faecal Enterobacteriaceae isolated at the Children's Emergency Hospital, Khartoum was investigated. Twenty-four transconjugant plasmids, coding for 11 different resistance patterns, each of molecular weight 62 MDa. were studied using four restriction enzymes; Pst I, Eco R I, Hind III and Ara II. Fifteen different digest profiles were obtained. Restriction profiles discriminated between plasmids with differing resistance patterns and demonstrated homology of plasmids with common resistance patterns. Restriction endonuclease digest patterns provide a potentially rapid and reproducible method of plasmid classification, that could contribute towards surveillance systems in tropical countries with a high prevalence of antimicrobial resistance.

Ross River virus (RRV) is the most common mosquito-borne infection in Australia. RRV disease is characterised by joint pain and lethargy, placing a substantial burden on individual patients, the healthcare system and economy. This burden is compounded by a lack of effective treatment or vaccine for the disease. The complex RRV disease ecology cycle includes a number of reservoirs and vectors that inhabit a range of environments and climates across Australia. Climate is known to influence humans, animals and the environment and has previously been shown to be useful to RRV prediction models. We developed a negative binomial regression model to predict monthly RRV case numbers and outbreaks in the Darling Downs region of Queensland, Australia. Human RRV notifications and climate data for the period July 2001 – June 2014 were used for model training. Model predictions were tested using data for July 2014 – June 2019. The final model was moderately effective at predicting RRV case numbers (Pearson's r = 0.427) and RRV outbreaks (accuracy = 65%, sensitivity = 59%, specificity = 73%). Our findings show that readily available climate data can provide timely prediction of RRV outbreaks.

Myxomatosis on the Western Plains is an enzootic disease in contrast with the epizootic pattern which is general in eastern Australia. The most unusual aspects are the presence of significant numbers of diseased rabbits throughout the winter and the continuously low percentage of rabbits with antibodies to myxoma virus.

Climatic and topographic conditions are unsuited to the production of the high densities of mosquitoes necessary for widespread epizootics. Under these conditions the effects of less efficient methods of myxomatosis transmission are apparent. The unusual epidemiology of myxomatosis has resulted in selection for virulence of the virus similar to that which has occurred under summer epizootic conditions. All field strains are now in the mid range of virulence.

Previous studies have suggested that a hospital patient's risk of developing healthcare facility-onset (HCFO) Clostridioides difficile infections (CDIs) increases with the number of concurrent spatially proximate patients with CDI, termed CDI pressure. However, these studies were performed either in a single institution or in a single state with a very coarse measure of concurrence. We conducted a retrospective case-control study involving over 17.5 million inpatient visits across 700 hospitals in eight US states. We built a weighted, directed network connecting overlapping inpatient visits to measure facility-level CDI pressure. We then matched HCFO-CDIs with non-CDI controls on facility, comorbidities and demographics and performed a conditional logistic regression to determine the odds of developing HCFO-CDI given the number of coincident patient visits with CDI. On average, cases' visits coincided with 9.2 CDI cases, which for an individual with an average length of stay corresponded to an estimated 17.7% (95% CI 12.9–22.7%) increase in the odds of acquiring HCFO-CDI compared to an inpatient visit without concurrent CDI cases or fully isolated from both direct and indirect risks from concurrent CDI cases. These results suggest that, either directly or indirectly, hospital patients with CDI lead to CDIs in non-infected patients with temporally overlapping visits.

The explosive outbreak of COVID-19 led to a shortage of medical resources, including isolation rooms in hospitals, healthcare workers (HCWs) and personal protective equipment. Here, we constructed a new model, non-contact community treatment centres to monitor and quarantine asymptomatic and mildly symptomatic COVID-19 patients who recorded their own vital signs using a smartphone application. This new model in Korea is useful to overcome shortages of medical resources and to minimise the risk of infection transmission to HCWs.

In September 2002, facsimiles were sent to 360 primary-care physicians alerting them to a local outbreak of Q fever. The physicians subsequently submitted serology samples on significantly more patients than in a previously comparable period in 2001. Facsimile cascade assists effective communication with primary-care physicians in an outbreak investigation.

1. When fleas bit through films of Tuberculin, Vaccine Lymph, and Staphylococcus Emulsion lying upon the human skin, no inoculation was observed in 188 instances out of 195. In six of the experiments with Tuberculin, inoculation followed, which possibly was not due to the flea-bites. Controls gave positive results.

2. When the same materials were rubbed over recent flea-bites, no inoculations followed. Controls were positive.

3. A very minute dose of Tuberculin, such as might be conveyed by a flea's proboscis, will produce a recognisable reaction in a susceptible person.

4. The bearing of the results on the question of plague transmission is discussed.

Two units, within a mouse-breeding colony, with different breeding systems, have been compared from the point of view of general healthiness of the breeding stock. In one unit the monogamous-pair system, involving post-partum oestrus mating, was employed and in the other the harem system, with isolation of the pregnant females for each litter-down until after the post-partum oestrus. The two units were housed separately and had different staffs. The monogamous-pair unit was accommodated in four small rooms not directly connected; the harem unit in two larger connecting rooms. The methods of cageing, bedding, feeding, watering, care, culling and subsequent procedures were identical for both units and the same system of recording individual detailed information relating to health and breeding was followed for the two units. The size of the two populations studied was 1198 and 1024, respectively, the larger number belonging to the harem unit in which the mice were retained for a significantly longer period. These mice were moved more frequently and handled much more often.

Apart from a small outbreak of Tyzzer's disease (in the harem-bred unit) and sporadic cases in both units spread over the whole period of the survey—some 3–4 years—the general health of the two units was good. There were no cases of salmonella infection, mousepox, pasteurellosis or other serious infections. Throughout the period both units maintained a high standard of productivity and there was no evidence that the mating of the monogamous pairs at the post-partum oestrus led to any weakness or ill health. As would be expected, however, the losses from death and culling were greater among the females in both units.

The health record of the monogamous-pair bred unit was consistently higher than that of the harem-bred unit. There were more cases of Tyzzer's disease in the harem-bred mice and more evidence generally of ill health in this unit. Infertility was three times greater with the harem-bred mice as compared with those in the monogamous-pair unit.

Details of the two systems are discussed and although the records maintained for the two may not be strictly comparable it is concluded that, under the conditions obtaining, the monogamous-pair breeding system yielded a healthier colony of mice than the harem breeding system.

I should like to thank Dr J. S. Patterson and Mr R. Cook for placing many of their records at my disposal, Mr S. Peto and his staff for carrying out much of the tedious compilation of data, and Dr D. W. Henderson, F.R.S., for affording me facilities for this work. To these I am especially grateful for their interest, advice and assistance.

The prevalence of Chagas disease has decreased in the Americas region due to vector control measures. However, non-vectorial transmission through blood transfusions and organ transplantation has gained importance in recent years. Screening among blood and organ donors are essential to reduce Trypanosoma cruzi transmission and could provide information to estimate population prevalence. We conducted a cross-sectional study on the prevalence of immunoglobulin G (IgG) antibodies against T. cruzi in healthy blood donors, solid organ donors and heart transplant recipients from 2012 to 2019. We found a total of 99 357 IgG T. cruzi results during the study period. The cumulative seroprevalence in healthy blood donors was 0.13% (95% confidence interval (CI) 0.10–0.15), in organ donors was 0.53% (95% CI 0.06–1.92) and in heart transplant recipients was 3.03 (95% CI 0.07–15.75). Seroprevalence trend in healthy blood donors showed annual increase between 2012 and 2015, decreasing in the following years. No trend was seen in organ donors neither heart recipients. Adjusted rates did not show difference by sex and age among blood donors. No significant increases in seroprevalence T. cruzi were found during the study period. T. cruzi transmission remains low.

1. Immunity cannot be completely explained by antigen-antibody reactions, even if the term ‘antibodies’ be made sufficiently elastic to include various obscure properties which are exhibited, in vivo, in the actively immune animal. Various other factors have to be considered. One of these is the influence of stimuli upon the vital capacities of bacteria.

2. Transmissible bacterial autolysis appears to be due to a stimulus acting upon the growing bacterial cell and leading to the splitting off of a certain number of daughter-cells which are non-viable, and consequently undergo autolysis.

3. Transmissible autolysis is not due to a stimulus sui generis but is no more than a particular incident in the general phenomena of bacterial variation.

4. The secretions of bacteria in pure culture may stimulate, control, or retard their growth and may lead to the production of variants.

5. When introduced into the animal body, bacteria encounter stimulants of animal origin which may be either favourable or unfavourable to their growth and are to be distinguished from the stimulants attributable to the bacteria themselves.

6. One aspect of the differences between natural immunity and natural susceptibility may be interpreted as due to differences in the stimuli inherent in the particular animal species and to consequent differences in their effects upon the particular bacterial species.

7. Similarly, when no better explanation is available, the acquired immunity (active or passive) of a susceptible animal may be interpreted as a change of the animal's stimulant action from one which was favourable (or indifferent) to the growth of a bacterium to one which is adverse, i.e., a stimulant to the reproduction of daughter-cells which are non-viable in the animal body.

8. Leucocytes are one of the sources of material possessing two kinds of properties, viz., (a) stimulant action on the growth capacities of cells (both bacterial and animal) and (b) enzyme action on the constituents which living and dead cells possess in common. The older researches on the characters of leucocytic extracts were occupied with (b), though they may occasionally be linked up with (a), since there are some indications that their leucocytic material was also acting as „lytic substance.”

9. In some cases it must remain, for the present, an open question whether demonstrable antibacterial action is attributable to some more or less obscure enzymes or to what I have termed „stimuli.”

10. A stimulus may be a substance which is also an antibody, and its stimulative properties may be highly specific. But it would be absurd to assume that for each special kind of stimulative effect there is a special and chemically distinctive kind of stimulus. Both stimuli and antibodies usually possess a wide range of different combining affinities which cannot be explained on the „mosaic” theory that each different combination is due to the presence (in the stimulus or antibody) of a different chemical group.

11. A stimulus, as distinct from a food, causes the bacterial cell to function in a particular way but is not incorporated as part of the structure of the cell. This convenient distinction, however, does not imply that there is necessarily a sharp line of demarcation between a stimulus and a food.

No hygienist has any doubt that diseases of the intestinal tract, especially the enteric fevers, may be spread by the consumption of shellfish. Clinical experience, often repeated, led to this conclusion long before the bacteriologist had been able to detect the presence of the causative organism in the shellfish. In fact it is only within the past year that definite proof has been afforded by the exceedingly valuable work of Wilson (1928), who found B. typhosus in cockles taken from Belfast Lough.