Plagge in 1886 observed that but few water filters prevented the direct transmission of micro-organisms and that all gave contaminated filtrates after being a few days in operation. This result has been widely confirmed, especially by Woodhead and Wood (1894, 1898), and by Bulloch and Craw (1906). Plagge considered that in the case of those filters which did not permit of the immediate or direct transmission of germs the subsequent failure of the filters was due to the gradual growth of the organisms through the filter mass, a view which has been adopted by v. Esmarch (1902) and is generally accepted.

1. Salmonella typhi, strain Ty2, grown in vivo and employed as acetone-dried vaccine possessed a higher immunizing potency than the descendants of the same parent strain grown in vitro and employed as vaccine.

2. When 2 × 108in vitro-grown bacteria were employed as challenge, the immunizing effects of both types of vaccine were more marked than after administration of 2 × 108in vivo-grown bacteria as challenge.

3. The higher potency of the in vivo-grown vaccine was apparent in all experiments, whether the challenge strain was grown in vivo or in vitro.

4. Immunogenic substances were isolated from infected organs of mice and guinea-pigs, and an immunogenic substance from the peritoneal fluid of the infected guinea-pigs was concentrated by precipitation with ethanol.

Studies on climate variables and food pathogens are either pathogen- or region-specific, necessitating a consolidated view on the subject. This study aims to systematically review all studies on the association of ambient temperature and precipitation on the incidence of gastroenteritis and bacteraemia from Salmonella, Shigella, Campylobacter, Vibrio, and Listeria species. PubMed, Ovid MEDLINE, Scopus, and Web of Science databases were searched up to 9 March 2023. We screened 3,204 articles for eligibility and included 83 studies in the review and three in the meta-analysis. Except for one study on Campylobacter, all showed a positive association between temperature and Salmonella, Shigella, Vibrio sp., and Campylobacter gastroenteritis. Similarly, most of the included studies showed that precipitation was positively associated with these conditions. These positive associations were found regardless of the effect measure chosen. The pooled incidence rate ratio (IRR) for the three studies that included bacteraemia from Campylobacter and Salmonella sp. was 1.05 (95 per cent confidence interval (95% CI): 1.03, 1.06) for extreme temperature and 1.09 (95% CI: 0.99, 1.19) for extreme precipitation. If current climate trends continue, our findings suggest these pathogens would increase patient morbidity, the need for hospitalization, and prolonged antibiotic courses.

The impact of influenza and pneumonia on individuals in clinical risk groups in England has not previously been well characterized. Using nationally representative linked databases (Clinical Practice Research Database (CPRD), Hospital Episode Statistics (HES) and Office for National Statistics (ONS)), we conducted a retrospective cohort study among adults (≥ 18 years) during the 2010/2011–2019/2020 influenza seasons to estimate the incidence of influenza- and pneumonia-diagnosed medical events (general practitioner (GP) diagnoses, hospitalisations and deaths), stratified by age and risk conditions. The study population included a seasonal average of 7.2 million individuals; approximately 32% had ≥1 risk condition, 42% of whom received seasonal influenza vaccines. Medical event incidence rates increased with age, with ~1% of adults aged ≥75 years hospitalized for influenza/pneumonia annually. Among individuals with vs. without risk conditions, GP diagnoses occurred 2–5-fold more frequently and hospitalisations were 7–10-fold more common. Among those with obesity, respiratory, kidney or cardiovascular disorders, hospitalisation were 5–40-fold more common than in individuals with no risk conditions. Though these findings likely underestimate the full burden of influenza, they emphasize the concentration of disease burden in specific age and risk groups and support existing recommendations for influenza vaccination.

In the two preceding communications we have discussed the calcium balances and weight increase of natives, both adult and growing, on certain institution diets, with and without additions.

Various considerations pointed to a relative or absolute deficiency of calcium in the above diets. The experimental additions made, therefore, were (1) a mineral mixture reproducing closely the ash of cows' milk; (2) cod-liver oil; (3) cod-liver oil plus the mineral mixture; (4) olive oil plus KI; (5) milk.

The Ethiopian government has several initiatives to expand and intensify the dairy industry; however, the risk of bovine tuberculosis (bTB) spread is a challenge. To assess the rate of expansion and risk factors for transmission of bTB within-herds, we carried out a repeated cross-sectional survey at two time points, 2016/17 and 2018, in three regional cities, namely, Gondar, Hawassa and Mekelle, representing the emerging dairy belts of Ethiopia. The total number of herds involved was 128, comprising an average of 2303 cattle in each round. The Single Intradermal Comparative Cervical Tuberculin (SICCT) test was used to identify reactor status and data on herd-level risk factors were collected using a structured questionnaire. In the first survey, the apparent prevalence of bTB, as measured by the SICCT test, was 4.5% (95% CI 3.7–5.4%) at the individual animal-level and 24% (95% CI 17.5–32%) at the herd-level. There was no statistically significant change in the overall apparent prevalence or regional distribution at the second survey, consistent with the infection being endemic. The incidence rate was estimated at 3.6 (95% CI 2.8–4.5) and 6.6 (95% CI 3.0–12.6) cases/100 cattle (or herd)-years at the animal- and herd-levels, respectively. Risk factors significantly associated with the within-herd transmission of bTB were age group and within-herd apparent prevalence at the start of the observation period. We noted that farmers voluntarily took steps to remove reactor cattle from their herds as a consequence of the information shared after the first survey. Removal of reactors between surveys was associated with a reduced risk of transmission within these herds. However, with no regulatory barriers to the sale of reactor animals, such actions could potentially lead to further spread between herds. We therefore advocate the importance of setting up regulations and then establishing a systematic bTB surveillance programme to monitor the impact prior to implementing any control measures in Ethiopia.

1. The effects of morphine, heroin, codeine, dilaudid, dicodid and eukadol upon the caecum and colon are described.

2. Small quantities of morphine produce a rapid increase in tone and amplitude of movements lasting many hours. Large doses result in a spastic contraction of the intestine with diminution of peristaltic movements.

3. The effects of heroin closely resemble those of morphine; it usually produces a greater increase in tone than morphine but the movements are not so great. Heroin is about 30% more active than morphine.

4. Codeine appears to be the weakest member of the series. It causes a slight increase in tone and peristaltic movements which never last very long.

5. Dilaudid produces effects which closely resemble those of morphine and heroin but it is approximately 7.5 times more potent than morphine. Intestinal tone is increased at first but may be subnormal at the 3 or 4 hr. stage. The maximum amplitude of peristaltic movements is seen at the 3 hr. stage.

6. Dicodid increases the tone, and particularly the peristaltic movements. The effects upon the general tone are moderate, much less than those of morphine, heroin or dilaudid. The increase in the amplitude of the movements is, however, much greater than with any other of the drugs. It differs from the others in producing its effects only after a long latent interval of 1–2 hr.

7. Eukadol increases the peristaltic movements in a marked way and is more active in this respect than either morphine or heroin, but is inferior to dicodid. Its effects upon tone are very transient and never very marked.

8. The effects of all these drugs upon the tone and peristaltic movements are at once abolished by adrenalin or atropine. Except morphine and eukadol, these drugs failed to produce their effects when administered after full doses of atropine.

9. The injection of hypophysin during the phase of increased muscular activity following the injection of these drugs, always causes an immediate abolition or diminution of the peristaltic movements and loss of tone to a subnormal level. There is however a rapid recovery from this state and approximately 5–10 min. later the movements are increased to an amplitude far in excess of that seen perior to the injection of hypophysin.

Since the discovery of ABO blood types, there has been mounting evidence of the association between blood types and infectious diseases. However, so far, there is rarely available research about the potential role of ABO blood types in haemorrhagic fever with renal syndrome (HFRS) infection. Our aim was to investigate the relationship between ABO blood types and the development of HFRS infection in Qingdao, China. We carried out a retrospective study enrolling 116 HFRS patients as the case group and 373 healthy subjects as the control group. ABO blood type distribution was analysed using the Chi-square test and logistic regression analysis. Results showed that the distribution of ABO blood types between the two groups was significantly different (X2 = 18.151, P < 0.05). Blood type B was less frequently observed [odds ratio (OR), 0.404; confidence interval (CI), 0.238–0.684; P < 0.01], while blood type AB was more frequently observed in the case group (OR, 2.548; CI, 1.427–4.549; P < 0.01). Since significantly more males were affected than females, we further analysed the data by gender as well as blood types and obtained consistent results for males. Our findings indicated that populations with blood type AB might be more prone to HFRS infection, whereas those with blood type B might be less susceptible to HFRS infection, which will help to make risk stratification in infection control.

The general consideration of these results only tends to confirm the conclusions already arrived at. A uniform type of life evidently tends to a fairly uniform excretion of tissue cells from the udder. The case of Goat II also emphasises the effect of outside causes in increasing temporarily this excretion, while some of the samples of human milk show plainly that very high cell counts are not by any means necessarily connected with any diseased or disordered condition of the mammary gland.

We again emphasise the view we have already stated, viz. that in the cow the udder must be looked upon as an organ which has by breeding and selection been brought to an artificial condition of milk secretion and that this has been accompanied by a stimulation of the tissues to cell proliferation and that this proliferation may quite easily be caused to become abnormally great, leading to the appearance of an increased number of cells in the secretion. In support of this view we lay great stress on the fact constantly noticed by us, viz. that when the cell count is high for any reason, the cells themselves are always well-defined, showing little signs of degeneration, and also stain in a much more characteristic and definite manner, a fact which is diffcult to explain if they are to be considered to be blood elements.

Strains of Corynebacterium diphtheriae isolated from a small outbreak in the restricted environment of a Mental Hospital were examined. All belonged to one serotype, but there was marked variation in diphthericin type, in sensitivity to bacteriophages and in the minor antigens possessed. One strain was non-virulent and laboratory-produced variants of this non-virulent strain showed changes in some of the characteristics used in the identification and typing of the organism, such as diphthericin type, sensitivity to bacteriophages and diphthericins, virulence, starch fermentation and, to a lesser extent, in antigenic structure. The epidemiological and experimental findings are consistent with the hypothesis that the strains isolated, both in the hospital and in the laboratory, were derivatives of a single parent and the mechanism of some of the variations could be related to changes in some structural component such as the cell membrane or the cell wall.

Pen and field trials were conducted to assess the performance of the acute rodenticide pyriminil against the house mouse (Mus musculus L.). Four types of poison treatment were carried out using penned family groups of warfarin-resistant mice supplied with alternative plain foods. In each treatment pyriminil was included at 2% in a wholemeal flour/pinhead oatmeal/corn oil bait. Mortality was highest (46/54; 85·2%) when poison bait was offered for 4 days following 3 days of pre-baiting The same pre-baiting and poisoning technique was adopted in five field trials carried out against mice infesting farm building The efficacy of each poison treatment was estimated from the results of pre- and post-treatment census baitings; treatment success ranged between 53·7% and 96·7%, mean 80·5% It is concluded that pyriminil treatments are best carried out after a period of pre-baiting and that when pyriminil is used in this manner it is about as effective as zinc phosphide for the control of mice

In epidemiological studies of infectious disease, researchers often rely on specific cues of the host, such as clinical signs, as surrogate indicators of pathogen presence. A selection bias would manifest if the specific visual cues used in sampling for the pathogen were not representative of the full range of signs caused by the strains of that pathogen. In our molecular epidemiological studies of Escherichia coli associated with avian cellulitis in broilers, we collect carcasses at the processing plant based on visual cues of lesion morphology. Therefore, the objectives of this study were to: (1) explore the potential impacts of selection bias in an application of infectious disease epidemiology, and (2) utilize a validation protocol to assess the potential for selection bias in our molecular epidemiological studies of E. coli and avian cellulitis. In two different trials, E. coli DNA fingerprints were compared between birds that our observers collected and the birds that the observers missed. Using Fisher's exact tests and simulation models, we determined that the isolates collected by the observers were not significantly different from the isolates missed by the observers (P>0·60 in both trials). Our method of selecting birds suspected of having cellulitis did not significantly bias our inferences about the population of E. coli associated with cellulitis in the flock. We encourage more investigators to critically assess the relationship of the sample to the target population in epidemiological studies of infectious disease.

Recently conflicting statements have been published in various countries on the prevalence and increased mortality from cancer, i.e. malignant disease in general. Statistics show a definite upward trend in the annual death rate from cancer, but opinions differ as to whether the increased mortality represents the actual increase in the incidence of the disease or is explained by such factors as the increased average age at death, improved methods of diagnosis and more careful records of the cause of death.

The amount of clerical work involved, and the ramifications of the record system used, in an animal laboratory, are conditioned by the purpose for which the colony is maintained, and dependent upon how anxious its custodians are to control its size and guide its future. If, for instance, ease of operation and minimization of clerking is to be the overriding consideration one may secure a good supply of young rats by the simple process of allowing a flock of adult animals the freedom of a warm room containing bedding and food. One enters at intervals to clean and feed, and, eventually, to remove, for experimental work, those youngsters that look big enough to fend for themselves, taking care, at the same time, to leave a few of each sex to grow to maturity and guarantee the next generation. An occasional census of population and production is all that is necessary in the way of records.

In a paper on “The Spread of Bacterial Infection” (Journal of Hygiene, xix. No. 4, March 22, 1921) Dr W. W. C. Topley has shown the results of many months' observation of the progress of an epidemic in a population of mice. The author thus describes the experiment: “This experiment lasted from May 21, 1919, until June 11, 1920.…The epidemic started about the middle of October, 1919, and continued in the manner to be described until the conclusion of the experiment.…The period May 21 to September 17 is omitted.…During this time there was no indication of the active spread of infection.…The whole experiment may be divided roughly into four periods. The first extends from May 21 to Sept. 17, and has been referred to already. From Sept. 18 and onwards, only normal mice were added to the cage. From this date until Jan. 5, 1920, the mice were added in such a way as to keep the total number in the cage roughly constant. From Jan. 6 to April 27, 1920, three normal mice were added each day, except on two occasions when none was added. The number of mice in the cage during this period varied from day to day, reaching a maximum immediately before each considerable wave of mortality, and falling to a minimum just before its cessation. During the final period from April 28 to June 11, 1920, two normal mice were added daily instead of three.”

During the past four years it has been part of our routine work to examine samples of ground waters from wells and springs in various portions of Ohio, and, in so doing, organisms have been obtained from time to time conforming to the tests usually given as differentiating faecal bacteria.

In 2007–2008, the city of Rio de Janeiro underwent an epidemiological change, with increases in the incidence in children and in severe forms of dengue. To describe the clinical profile and spatial distribution of dengue we performed an ecological study based on dengue surveillance data using the Brazilian classification (2005): dengue fever, dengue haemorrhagic fever (DHF) and dengue with complications. χ2 test was used to describe the clinical and socio-demographic variables (P < 0.05). Spatial distribution of incidence and case-fatality was explored with thematic maps, Moran and Geary indices (P < 0.05). Of the total of 151 527 dengue cases, 38 808 met the inclusion criteria; 42.4% <18 years; 22.9% dengue with complications and 2.7% DHF. Case-fatality was higher in infants (1.4%) and in DHF (7.7%). Bleeding was more frequent in adolescents and adults while plasma leakage was more common in preschoolers and schoolchildren. The highest incidence was found in the West Zone of the city, in a different area from that of the worst case-fatality (P < 0.05). Although the incidence of DHF was higher in schoolchildren, infants showed higher case-fatality. The area with the highest case-fatality did not present the highest incidence, which suggests problems in the organization of health services.