We studied the genetic diversity and the population structure of human isolates of Histoplasma capsulatum, the causative agent of histoplasmosis, using a randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) assay to identify associations with the geographic distribution of isolates from Mexico, Guatemala, Colombia and Argentina. The RAPD-PCR pattern analyses revealed the genetic diversity by estimating the percentage of polymorphic loci, effective number of alleles, Shannon's index and heterozygosity. Population structure was identified by the index of association (IA) test. Thirty-seven isolates were studied and clustered into three groups by the unweighted pair-group method with arithmetic mean (UPGMA). Group I contained five subgroups based on geographic origin. The consistency of the UPGMA dendrogram was estimated by the cophenetic correlation coefficient (CCCr = 0.94, P = 0.001). Isolates from Mexico and Colombia presented higher genetic diversity than isolates from Argentina. Isolates from Guatemala grouped together with the reference strains from the United States of America and Panama. The IA values suggest the presence of a clonal population structure in the Argentinian H. capsulatum isolates and also validate the presence of recombining populations in the Colombian and Mexican isolates. These data contribute to the knowledge on the molecular epidemiology of histoplasmosis in Latin America.

Futher experience with the method of measuring the precipitum obtained when experimenting with precipitating antisera has shown that finer degrees of reaction cannot be satisfactorily determined by means of the apparatus described by Nuttall. In the latter apparatus capillary tubes were used in which to measure the precipitum therein deposited. It is true that capillaries as far as possible of the same calibre were used, nevertheless we have found that different readings were obtained when experimenting with tubes of varying calibre, variations evidently due to physical causes which prevent an equal degree of “packing” of the deposit in tubes of unequal width. We have modified the method after finding that calibrated tubes of uniform bore gave more constant results, and have devised a simple apparatus which greatly facilitates the making of measurements.

Cold water (10° C) at ultra-high pressure (38·5–49 kg/cm2) was compared with (a) hot water (65·6–82·2° C) at low pressure (4·2–5·6 kg/cm2) and (b) hot water containing a detergent (2% (w/v) sodium silicate). Seven sites were examined in a beef abattoir and six in a bacon factory.

Three surfaces in the beef abattoir had lower residual colony counts (higher reductions) after hot water/low pressure than after cold water/high pressure. However, the differences were not significant (P > 0·05). The range of the mean log10 count/cm2 before cleaning was 4·02–5·15, and after cleaning 1·73–2·32 (hot water) and 1·9–2·85 (cold water).

On three of the remaining sites, the three methods were compared. The total differences between treatments were not significant (P > 0.05), although there was an effect of surface and an interaction between surface and treatment. The cold water produced lower residual counts on three sites in the bacon factory than the hot water (45–54°C). However, the differences were not significant on the remaining surfaces.

Mineral oils recovered from the peritoneal cavity of injected mice showed in all sixty-one instances, with the exception of liquid paraffin, a fall in the refractive index. This phenomenon is presumably due either to a chemical change (? oxidation or reduction) in the constituents of the oils brought about by the juices of the animal organism, or to a mechanical change resulting from the removal of selected constituents to other parts of the animal. This test will possibly prove to be superior to that of skin applications and estimation of the refractivity constants for measuring the amount of carcinogenic constituents in mineral lubricating oils and it has the advantage of necessitating the use of only one animal instead of 100. We are of opinion that our experiments may be of far-reaching importance. They carry us a definite step nearer to the understanding of the mechanism of cancer formation.

Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced as a biological control agent. However, little is known about the rate at which this evolutionary change occurred. We collated data from challenge trials that estimated rabbit resistance to myxomatosis in Australia and expressed resistance on a continuous scale, enabling trends in its development to be assessed over 45 years up to 1995. Resistance initially increased rapidly, followed by a plateau lasting ten years, before a second rapid increase occurred associated with the introduction of European rabbit fleas as myxoma virus vectors. By contrast, in the United Kingdom, where rabbit flea vectors were already present when the myxoma virus initially spread, resistance developed more slowly. No estimates of rabbit resistance to myxomatosis have been made for almost 30 years, despite other highly lethal rabbit pathogens becoming established worldwide. Continued testing of wild-caught rabbits in Australia to determine current levels of resistance to myxomatosis is recommended to assess its current effectiveness for managing pest rabbits. Given the economic and environmental significance of invasive rabbits, it would be remiss to manage such biological resources and ecosystem services poorly.

Methicillin-resistant Staphylococcus aureus (MRSA) transmission in hospital wards is associated with adverse outcomes for patients and increased costs for hospitals. The transmission process is inherently stochastic and the randomness emphasized by the small population sizes involved. As such, a stochastic model was proposed to describe the MRSA transmission process, taking into account the related contribution and modelling of the associated microbiological environmental contamination. The model was used to evaluate the performance of five common interventions and their combinations on six potential outcome measures of interest under two hypothetical disease burden settings. The model showed that the optimal intervention combination varied depending on the outcome measure and burden setting. In particular, it was found that certain outcomes only required a small subset of targeted interventions to control the outcome measure, while other outcomes still reported reduction in the outcome distribution with up to all five interventions included. This study describes a new stochastic model for MRSA transmission within a ward and highlights the use of the generalized Mann–Whitney statistic to compare the distribution of the outcome measures under different intervention combinations to assist in planning future interventions in hospital wards under different potential outcome measures and disease burden.

Co-agglutination between the somatic agglutinins of B. typhosus and B. paratyphosus B occurs more frequently than between the flagellar agglutinins in the sera of typhoid and paratyphoid B fever cases. These co-agglutinins may develop early or late in the course of the disease.

It is suggested that the agglutinin absorption test is capable of distinguishing whether or not true co-agglutinins have been developed to the flagellar and somatic antigens of B. typhosus or B. paratyphosus B.

The problem of the comparative nutritive value of bread made from the various high grade white or “patents” flours and the so-called “standard” meal is of some interest. The inclusion of a considerable portion of the bran in standard bread is claimed to increase largely the nutritive value of the bread. It has been known for many years that wholemeal bread containing the bran particles was especially useful as an article of diet for persons suffering from constipation, the laxative effect being due partly to the mechanical presence of indigestible fibre, partly to the irritation of the intestinal wall by the sharp bran particles causing increased peristalsis. This effect is to some extent lost after prolonged feeding.

Dengue infection in China has increased dramatically in recent years. Guangdong province (main city Guangzhou) accounted for more than 94% of all dengue cases in the 2014 outbreak. Currently, there is no existing effective vaccine and most efforts of control are focused on the vector itself. This study aimed to evaluate different dengue management strategies in a region where this disease is emerging. This work was done by establishing a dengue simulation model for Guangzhou to enable the testing of control strategies aimed at vector control and vaccination. For that purpose, the computer-based dengue simulation model (DENSiM) together with the Container-Inhabiting Mosquito Simulation Model (CIMSiM) has been used to create a working dengue simulation model for the city of Guangzhou. In order to achieve the best model fit against historical surveillance data, virus introduction scenarios were run and then matched against the actual dengue surveillance data. The simulation model was able to predict retrospective outbreaks with a sensitivity of 0.18 and a specificity of 0.98. This new parameterisation can now be used to evaluate the potential impact of different control strategies on dengue transmission in Guangzhou. The knowledge generated from this research would provide useful information for authorities regarding the historic patterns of dengue outbreaks, as well as the effectiveness of different disease management strategies.

A Technique for drying serum proteins from the frozen state has been described by Greaves & Adair (1939). For war requirements the procedure has been to dry in 12 oz. medical flats into each of which is put 200 c.c. of serum. The bottles are then placed in a −20° C. cold room on shelves slightly inclined to the horizontal. The inclination is to allow the maximum quantity of serum to be dried consistent with the exposure of a reasonable surface area from which to dry. This method of freezing produces a wedge-shaped block of serum in the bottle (Fig. 1) and is very efficient. Large amounts of serum for the use of the Army have been dried in this manner by Greaves and his colleagues.

The poliomyelitis epidemic of 1937 in Denmark was investigated by means of information obtained about each individual case.

It occurred in the usual season, culminating in September. The districts involved were limited largely to Zealand, including Copenhagen. It is of particular interest that the disease occurred also in rural districts that were the sites of similar epidemics in 1933 and 1934.

It is noted as a peculiar fact that poliomyelitis seems to be unable to invade the whole of Denmark within one season.

The 1937 epidemic comprised 1200 notified cases, of whom 599 developed paralysis and 113 died. Everything suggests that the number of non-paralytic cases was far greater than the number of cases notified. Influenza and angina were notified with striking frequency in the districts where poliomyelitis prevailed.

The morbidity, frequency of paralysis and mortality were greater among males than among females.

A change in the age distribution during the past 35 years is pointed out. In 1937, 30% of the patients were over 15 years, and about 14% over 20 years; of those who died 45% were over 15 years, 20% over 20 years.

Convalescent serum was not employed in Copenhagen, but in the provinces 489 patients were treated with, and 400 without, serum. The principles of the treatment were the same as in 1934. Serum was given early in the disease, as a rule intravenously.

Data from the 1997–2004 Surveys of Prevalent HIV Infections Diagnosed were analysed by three geographical areas of residence and treatment to describe the heterogeneous growth of the HIV epidemic in England and provide projections to 2007. Between 1997 and 2004, the number of diagnosed HIV-infected adults resident in England increased by 163% (14223 to 37459). Within the ‘London environs’ the increase was 360% (742 to 3411), within the rest of England 219% (4417 to 14088) and within London 120% (9064 to 19960). By 2004, the London environs had the largest proportion of infections acquired through heterosexual sex (and in particular women) and the most recently diagnosed population. Projections indicate over half of diagnosed HIV-infected adults will live outside London by 2007. The epidemiology of diagnosed HIV infection within the London environs is likely to be a predictor of future trends in England overall.

Detailed instructions are given for the preparation of a purified and stabilized suspension of vaccinia elementary bodies. This is intended to take the place of crude glycerinated calf or sheep lymph vaccine. The technique consists of a series of procedures involving mechanical disintegration of the skin pulp, maintenance of dispersion by means of a non-ionic detergent, fractional centrifugation and bacterial disinfection. Stability of the purified virus is secured by suspending it in a dilute buffer containing peptone and polyvinylpyrrolidone. Experiments are described which illustrate the remarkable heat resistance of the virus in this suspending medium. The PVP-peptone also serves as an excellent menstruum for lyophilization. Production of this vaccine should be well within the competence of any properly equipped virus laboratory. Clinical trials are in progress.

All the work involved in the performance of the tissue culture assays was carried out by my former assistant Mr Edmund Bischoff. It is a pleasure to acknowledge both his technical skill and his enthusiasm. Mr T. C. Campbell provided the crude calf pulp used in the preparation of some of the purified suspensions.

Various species of the Order Sarcosporidia, some of which have been studied with great care, infest the muscles of different kinds of birds and mammals. Muscle parasites resembling the one described below do not, however, appear to have been described.

Ever since artificial media have been used for the cultivation of micro-organisms, the question as to what is the best reaction—that is the degree of acidity or alkalinity—has been a moot point. It has been assumed gratuitously that there is an optimum reaction which is the same for all the common bacteria met with in the laboratory. In recent years however some attempts have been made to settle the question definitely, notably by Eyre and Deelemann. On enquiring what reaction of medium was adopted in six different London laboratories, Eyre found that very divergent standards were used, ranging from 20 units of acidity to 10 units of alkalinity on his scale. (20 units of acidity implies that 20 c.c. of normal alkali must be added to each litre to make it neutral to phenolphthalein. In the case of alkalinity the indicated number of c.c. of normal acid must be added.) The importance of having a definite reaction had until recently not impressed itself upon the majority of bacteriologists. The possibility that although many organisms may grow on media of comparatively widely differing reactions, yet only one of these reactions may be suitable for the growth of a more delicate kind, had been overlooked. Consequently they failed to grow bacteria which by careful adjusting of the reaction of the medium could be readily cultivated. Martin (1910), for example, has lately pointed out the ease with which gonococcus can be made to grow on serum agar if the reaction is carefully adjusted. In later years the subject has assumed still more importance in connection with the production of bacterial toxins, which have been submitted to a large amount of investigation. In the production of diphtheria toxin it was soon recognised that bouillon containing more alkali than is usually employed for ordinary bacteriological work, yielded the most toxin, and even various devices were invented to avoid the initial production of acid which usually takes place as the consequence of bacterial growth in a sugar-containing medium. Madsen (1896) has made a thorough examination of the factors governing the production of diphtheria toxin. By following the reaction of a growing culture from day to day he found two different types of growth occur,—one in which the medium increases in acidity without abatement, and such cultures are atoxic; in the other the primary increase in acidity is followed by a decrease, and subsequent increase in alkalinity. These cultures are sometimes toxic. The two conditions seemed to have relation to the amount of alkali added in the preparation of the bouillon, in that a strongly alkaline medium gave an alkaline end reaction while a less alkaline medium gave sometimes an acid and sometimes an alkaline end reaction.

Although an effective whooping cough vaccine has been available in the UK since the 1950s, its current association with neurotoxicity has resulted in poor uptake: as a consequence major epidemics (with significant morbidity and mortality) arc still being experienced.

Component (sub-unit) vaccines, which incorporate those antigens thought to be concerned with generating a protective effect, have been developed and are now available for field testing. This paper addresses how such a vaccine might be evaluated, the organization of a trial and the difficulties to be expected.

1. B. dysenteriae of Flexner has been found in the stools of 17 out 19 cases of asylum dysentery; no evidence of the presence of the Shiga type was obtained.

2. In 18 cases examined one week to 14 months after an attack of dysentery, B. dysenteriae was found only once (3 weeks).

3. No evidence has been obtained of the presence of B. dysenteriae the faeces of ward contacts (26 cases) with either normal or diarrhoeic stools.

4. The fermentative reactions of B. dysenteriae of Flexner towards maltose and cane-sugar are variable.

The following study completes the examination of the data derived from certain physical and physiological measurings of adolescent boys at the Manchester Grammar School, taken during the last ten years with a view to enquiring whether any definite relationship could be discovered between such measurings, considered singly or in combination, and either general scholasticattainments or special aptitudes in school sports and games. If such relationship, indicating either general or particular aspects of health and vitality, could be discovered, then, although spontaneity of choice in classroomand playing-fields should always be jealously guarded, yet the cause of many failures might be revealed and such innate energy as the boy may possess be directed into more appropriate channels.

Within China's Poyang Lake region, close interactions between wild migratory birds and domestic poultry are common and provide an opportunity for the transmission and subsequent outbreaks of highly pathogenic avian influenza (HPAI) virus. We overlaid a series of ecological factors associated with HPAI to map the risk of HPAI in relation to natural and anthropogenic variables, and we identified two hotspots for potential HPAI outbreaks in the Poyang Lake region as well as three corridors connecting the two hotspot areas. In hotspot I, there is potential for migratory birds to bring new avian influenza (AI) strains that can reassort with existing strains to form new AI viruses. Hotspot II features high-density poultry production where outbreaks of endemic AI viruses are likely. The three communication corridors that link the two hotspots further promote HPAI H5N1 transmission and outbreaks and lead to the persistence of AI viruses in the Poyang Lake region. We speculate that the region's unevenly distributed poultry supply-and-demand system might be a key factor inducing HPAI H5N1 transmission and outbreaks in the Poyang Lake region.