1. The tuberculin reaction properly applied is a reliable test of the presence of tuberculosis in cattle.

2. A method of segregation is described by which any herd can be rendered tuberculin negative in three to four years without diminution of the herd.

3. Evidence is given that recovery from a tuberculous infection can take place in cattle.

4. Calves can only be infected with tuberculosis after birth, such an infection may, however, take place extremely rapidly within the first few days of life.

5. Artificial feeding of calves with sterilised milk must be supplemented by some vitamine-containing food, otherwise “joint ill,” corresponding to rickets in human beings, will develop at about the third or fourth month. Bull calves are more susceptible to “joint ill” than heifers.

Vedder and Clark (1912), reporting observations on polyneuritis gallinarum based on experiments lasting for several years during which time over 200 fowls were used, make the following statement with regard to the relation between the amount of polished rice eaten and the time of development of neuritis.

During my work in Yucatán (tropical Mexico) I observed that we nearly always found by the current analysis of urine, a well pronounced indican reaction, certainly in more than 80% of the cases examined; and frequently the blue colour obtained by the Obermeyer or Jaffé reaction was so strong that one would have been inclined, if in Europe, to postulate the presence of intestinal obstruction or some serious intestinal disorder. Experience soon taught us however that the reaction had not the same significance in Yucatán and probably in other tropical countries as it possesses elsewhere. With the object of studying the underlying causes I suggested to one of my assistants an investigation of the indole-producing power of B. coli isolated from the faeces of different individuals. The results which have been published in a dissertation (Hernandez, 1908) were naturally very incomplete but the work led me to realise the importance of a quantitative indole-determination, and, as I did not find described in the literature any method suitable for our purpose, I proceeded to work out a method for myself. I used the Salkowski test, with nitrite of potassium, sulphuric acid, and extraction with amyl-alcohol, preparing a series of tubes containing determined quantities of indole in progressive concentrations. The indole I distilled from bacterial cultures. The scale kept well, having been preserved for three years in the dark and only brought into the light when in use.

1. The tuberculin reactions of 259 Hong Kong Chinese, mostly adults, were determined by the Mantoux method. Each individual was tested with various dilutions of both old tuberculin and tuberculo-protein.

2. Of 215 subjects above the age of twenty, 93·1 per cent, yielded positive reactions to old tuberculin in dilutions of 1/1000 or higher.

3. Tuberculo-protein compared with old tuberculin of similar dilutions did not yield such a high percentage of positive reactions, seldom produced such vigorous reactions and never caused vesiculation. (This may have been due to deterioration.)

Since the emergence of Middle East respiratory syndrome coronavirus (MERS-CoV), Singapore has enhanced its national surveillance system to detect the potential importation of this novel pathogen. Using the guidelines from the Singapore Ministry of Health, a suspect case was defined as a person with clinical signs and symptoms suggestive of pneumonia or severe respiratory infection with breathlessness, and with an epidemiological link to countries where MERS-CoV cases had been reported within the preceding 14 days. This report describes a retrospective review of 851 suspected MERS-CoV cases assessed at the adult tertiary-care hospital in Singapore between September 2012 and December 2015. In total, 262 patients (31%) were hospitalized. All had MERS-CoV infection ruled out by RT–PCR or clinical assessment. Two hundred and thirty (88%) of the hospitalized patients were also investigated for influenza virus by RT–PCR. Of these, 62 (27%) tested positive for seasonal influenza. None of the patients with positive influenza results had been vaccinated in the year prior to hospital admission. Ninety-three (36%) out of the 262 hospitalized patients had clinical and/or radiological evidence of pneumonia. This study demonstrates the potential benefits of pre-travel vaccination against influenza and pneumococcal disease.

Serosurveillance is an important epidemiologic tool for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), used to estimate infection rates and the degree of population immunity. There is no general agreement on which antibody biomarker(s) should be used, especially with the rollout of vaccines globally. Here, we used random forest models to demonstrate that a single spike or receptor-binding domain (RBD) antibody was adequate for classifying prior infection, while a combination of two antibody biomarkers performed better than any single marker for estimating time-since-infection. Nucleocapsid antibodies performed worse than spike or RBD antibodies for classification, but can be useful for estimating time-since-infection, and in distinguishing infection-induced from vaccine-induced responses. Our analysis has the potential to inform the design of serosurveys for SARS-CoV-2, including decisions regarding a number of antibody biomarkers measured.

The sporicidal activity of two solutions which have been used in the production of ‘sterile’ pre-injection swabs has been investigated. Propylene oxide (3·4 % w/w) and chlorhexidine diacetate (0·6% w/w), both made up in approximately 65% w/w propan-2-ol, were artificially contaminated with spores of Bacillus subtilis var. niger and swabs were impregnated with these; surviving spores were enumerated at various temperatures and times of storage. Chlorhexidine diacetate had no sporicidal activity, whereas the activity of propylene oxide was dependent on temperature. The former should not be considered a sterilant and the latter can only be considered such if a controlled incubation period at an elevated temperature is employed.

A case recently tried before Mr Justice Warrington (The Flour Oxidising Co., Ld. v. J. and R. Hutchinson) has brought to light, what I do not imagine is a matter of common knowledge, namely that large quantities of flour both in this country and abroad are artificially bleached in order it would appear primarily to satisfy the fancy of the public for white bread. The popular taste for the appearance of their food naturally leads the caterers to satisfy it; the yellowness of milk and its richness are usually associated together in the mind of the man in the street consequently it is very difficult now-a-days to purchase milk which has not been artificially coloured.

Candidemia is a life-threatening infectious disease that has varying incidences. Previous studies revealed the differences in clinical characteristics and outcomes between non-hospital-onset (NHO) and hospital-onset (HO) candidemia. This 4-year retrospective research included adult patients with candidemia in a tertiary medical centre in Taiwan, and cases were categorised as NHO and HO candidemia. Survival analysis and risk factors associated with in-hospital mortality were performed using the Kaplan–Meier method and multivariate Cox proportional-hazards models. The analysis included 339 patients, and the overall incidence was 1.50 per 1,000 admission person-year. Of the cases, 82 (24.18%) were NHO candidemia, and 57.52% (195/339) of patients were diagnosed with at least one malignancy. C. albicans was the most commonly isolated species, accounting for 52.21%. Patients with NHO candidemia had a higher proportion of C. glabrata but a lower ratio of C. tropicalis in comparison to the HO group. The all-cause in-hospital mortality rate was 55.75%. Multivariate Cox proportional-hazards models showed that NHO candidemia was a better outcome predictor (adjusted hazard ratio, 0.44). The administration of antifungal therapy within 2 days was a protective factor. In conclusion, NHO candidemia showed distinct microbiological characteristics and a better outcome than HO candidemia.

A study is described of influenza A anti-neuraminidase antibodies in the sera of young people of three different age groups. Each serum was individually absorbed with viruses containing the N2 neuraminidases of 1957, 1968 and 1972. Rabbit antisera prepared against the viruses were similarly absorbed. Results obtained with the animal sera suggested that these neuraminidases were antigenically distinct, but the human sera had a broader range of anti-neuraminidase activity and gave indication of asymmetric antigenic relationships. Earlier workers who surveyed anti-haemagglutinin antibodies reported that the virus of primary infection absorbed all antibodies, and the virus of secondary infection only those directed against itself. We too found that the virus of secondary infection absorbed only homologous anti-neuraminidase antibody. However, although the primary infecting virus did absorb some secondary antibody, this absorption was incomplete and it lessened with the lengthening of the time interval between the primary and secondary infecting viruses. A similar pattern was seen with anti-haemagglutinin antibodies.

Absorption of anti-neuraminidase antibodies from human sera proved much more difficult than absorption of anti-haemagglutinin antibodies particularly after repeated influenza virus infections. The relative rarity of antigenic shift in the neuraminidase subunit also creates problems in the interpretation of results of serum neuraminidase antibody surveys.

Bile is often referred to as if its chemical composition was constant and that by treating samples of bile with extractives similar results would be obtained, whereas samples of human bile differ to such an extent that the term bile in itself signifies little. Two samples of human bile may differ to such an extent that while one sample has the qualities of true bile as regards its bile salt content the other may be entirely devoid of lytic action on red blood cells. Numerous experiments made with human bile obtained during life and from the post mortem room have shown this to be correct. The actual bile salt content of bile can be judged by boiling the bile to remove much of the protein, and also to destroy bacterial activity and then contrast the haemolytic activity of the treated sample with a 1 per cent, solution of bile salt in normal saline.

1. The chain of evidence incriminating the house fly as a disseminator of typhoid fever is at present fairly complete, but many of the links are weak and not thoroughly strengthened by experimentation.

2. The bulk of experimental work has hitherto been done under highly unnatural and artificial circumstances and the results so obtained cannot be accepted unreservedly as giving a correct view of conditions in nature.

3. The experiments described in the present paper show that flies can ingest typhoid bacilli from natural matter, i.e. human faeces and urine, and carry them for a certain period of time.

4. There is no evidence to show that the typhoid bacilli multiply in the house fly. On the contrary the evidence goes to show that they are not adapted for prolonged life on or in the fly.

5. It thus follows that the house fly is a purely mechanical carrier of the typhoid bacillus and is not a natural “host” in the strict sense of the term.

6. Many bacilli closely resembling B. typhosus in cultural characteristics appear to be natural or, at least, common inhabitants of the intestine of the house fly. These are extremely likely to be mistaken for B. typhosus unless the most stringent tests are employed.

7. As might be expected there is evidence to show that a process of bacterial selection occurs in the fly's intestine. Some bacteria appear to flourish but others are rapidly eliminated. Among the latter must be numbered B. typhosus.

I have to thank my colleagues at the Lister Institute, particularly Dr Ledingham, Dr Henderson Smith and Dr Petrie, for much valuable help and advice during the course of these investigations. To Prof. Bainbridge, Dr Arkwright, Dr Penfold and Dr Macalister my thanks are also due, inasmuch as they helped to smooth over many difficulties both theoretical and practical.

Towards the end of the 19th century there was a need for standardized tests to determine the efficiency of disinfectants against the newly discovered bacterial pathogens. Methods had been developed in which disinfectants were tested on organisms soaked into thread or coated onto garnets. However, more appropriate were tests based on contact between dilutions of disinfectant and suspensions of organisms, which could be subcultured to detect residual infectivity.

The occurrence of antibody to myxoma virus in wild rabbits following epizootics is highest in the semi-arid north-west of Victoria and lowest in temperate southern Victoria. Occurrence ranges up to about 90% in the north-west and to about 70% in the south except on the Western Plains where epizootics are rare and antibody occurrence seldom exceeds 30%.

The establishment of the European rabbit flea may be changing the pattern of occurrence of antibody in the north-west by causing spring outbreaks of myxomatosis. It is suggested that the effects of the replacement of a simple recurring system of epizootic and breeding season several months apart by the occurrence of myxomatosis twice in the same year, once coincident with the breeding season, will be complex. The occurrence of detectable antibody may be less dependent on the infection rate and may be dependent to some extent on the relative timing of spring myxomatosis and the breeding season.

Concentrations of the rodenticide ergocalciferol (vitamin D2) in samples of rodent baits laid in foodstores and in the laboratory were monitored over several months. Bait samples were solvent extracted and ergocalciferol concentration determined by high pressure liquid chromatography (HPLC). Ergocalciferol levels were constant for more than 21 days in dry samples and did not fall by more than 30% in 100 days. When water (10% w/w) was added to the baits in the laboratory the ergocalciferol concentration fell by approximately 30 % in 30 days. In these wet laboratory samples there was a rapid visible growth of fungus and in normal rodent control use baits should have been replaced when such deterioration became evident.

C.coli is a significant cause of foodborne gastroenteritis worldwide, with the majority of cases attributed to C.jejuni. Although most clinical laboratories do not typically conduct antimicrobial susceptibility testing for C.coli, the rise in resistant strains has underscored the necessity for such testing and epidemiological surveillance. The current study presents clinical isolate characteristics and demographics of 221 patients with C.coli (coli and jejuni) infections in Northern Israel, between 2015 and 2021. Clinical and demographic data were collected from patient medical records. Susceptibility to erythromycin, tetracycline, ciprofloxacin, and gentamicin was assessed using the standard E-test. No significant correlations were found between bacterial species and patient ethnicity, patient gender, or duration of hospitalization. In contrast, significant differences were found between infecting species and patient age and age subgroup (P < 0.001). Furthermore, erythromycin resistance was observed in only 0.5% of the study population, while resistance to ciprofloxacin, tetracycline, and gentamicin was observed in 95%, 93%, and 2.3% of the population, respectively. The presented study underscores the need for routine surveillance of C.coli antibiotic resistance.

The twenty-four young women and one man treated in an ultra-clean isolation ward should have had a low incidence of staphylococcal infection on grounds of age, sex and clean environment alone. However, they apparently acquired new strains of Staph. aureus at the rate of 4·7/100 patient weeks (3·9 multiple resistant strains/100 patient weeks) from the sixth week after admission onwards.

Environmental factors contributing to infection included introduction of resistant strains by the patients on admission, contact between patients in the unit, and failure to eliminate nasal carriage in staff and patients.

Host susceptibility was increased by malignancy, and by antibiotic and cytotoxic therapy. The nasal carriage rate of Staph. aureus was significantly greater for patients with repeated episodes of leucopenia induced by cytotoxic drugs.

Immunoelectrophoresis of ultrasonically disrupted Haemophilus equigenitalis (contagious equine metritis organism) cells against rabbit and equine antisera disclosed at least 11 precipitating antigens. Two of these, a polysaccharide and a lipopolysaccharide–protein complex, were of high molecular weight and located on the cell surface. The remaining antigens were intracellular and were small- to medium-sized proteins.

The surface antigens were the most significant in relation to the serological response in infected horses. They also reacted with sera from apparently healthy cattle, but the reason for this was not determined. No serological cross-reaction between H. equigenitalis and species of Achromobacter and Moraxella was detected.

For a considerable number of years, Belfast has suffered from a high typhoid fever death-rate, and the investigations embodied in the following pages were undertaken at the request of the Corporation, with the purpose of determining the sanitary measures required to prevent, as far as possible, the occurence of typhoid fever in the city.