In an article on Pneumonoconiosis published in 1935 I attempted to simplify the problem of lung diseases caused by exposure to dust in industry by means of a classification which might allow of the placing of individual cases into appropriate categories. The importance of some such classification has been emphasized during the past year or so by the gradual realization of the fact that, especially in the South Wales coalfield, cases of more or less disabling lung conditions are frequently met with which cannot conscientiously be fitted into the category of “silicosis”, as defined at the International Conference at Johannesburg in 1930. These cases cannot be “certified” for compensation under existing Statutes, and yet present a picture of respiratory distress and dyspnoea on exertion which marks them out as quite unfit for work.

This study aimed to estimate the natural history and transmission parameters based on experimental viral shedding and symptom dynamics in order to understand the key epidemiological factors that characterize influenza (sub)type epidemics. A simple statistical algorithm was developed by combining a well-defined mathematical scheme of epidemiological determinants and experimental human influenza infection. Here we showed that (i) the observed viral shedding dynamics mapped successfully the estimated time-profile of infectiousness and (ii) the profile of asymptomatic probability was obtained based on observed temporal variation of symptom scores. Our derived estimates permitted evaluation of relationships between various model-derived and data-based estimations, allowing evaluation of trends proposed previously but not tested fully. As well as providing insights into the dynamics of viral shedding and symptom scores, a more profound understanding of influenza epidemiological parameters and determinants could enhance the viral kinetic studies of influenza during infection in the respiratory tracts of experimentally infected individuals.

Although true meningococci are represented in serum 1, as shown by the high agglutination figure reached with serum 1 in the case of subculture 8, it appears that the antigenic value of strain 1, as represented in serum 1, finds its chief expression in “giant” forms, the morphological equivalent of films 3, 14, 17, 23, 31 A, from the subcultures which give the highest readings with serum 1 (except 8), being mainly that of “giant” forms in various stages of development. As I showed in 1916 “giant” forms may be either large, small or intermediate in size, and can at once be distinguished from true meningococci on the warm-stage by the fact that they often multiply by unequal binary fission, and by the further fact that they often undergo in addition endo-chromatinolysis, giving rise directly to meningococci which then divide in the ordinary vegetative manner. These fertile “giant” forms are readily distinguishable form forms undergoing genuine involutionary changes, both by the sterility of the latter when observed on the warm stage and by their feebly-staining properties.

Different countries, especially Brazil, that have faced recurrent dengue epidemics for decades and chikungunya epidemics since 2014, have had to restructure their health services to combat a triple epidemic of arboviruses – Zika, dengue and Chikungunya – transmitted by the same vector, mainly Aedes aegypti, in 2015–2016. Several efforts have been made to better understand these three arboviruses. Spatial analysis plays an important role in the knowledge of disease dynamics. The knowledge of the patterns of spatial diffusion of these three arboviruses during an epidemic can contribute to the planning of surveillance actions and control of these diseases. This study aimed to identify the spatial diffusion processes of these viruses in the context of the triple epidemic in 2015–2016 in Rio de Janeiro, Brazil. Two study designs were used: cross-sectional and ecological. Sequential Kernel maps, nearest-neighbour ratios calculated cumulatively over time, Moran global autocorrelation correlograms, and local autocorrelation changes over time were used to identify spatial diffusion patterns. The results suggested an expansion diffusion pattern for the three arboviruses during 2015–2016 in Rio de Janeiro. These findings can be considered for more effective control measures and for new studies on the dynamics of these three arboviruses.

Surveillance for gastroenteritis rarely detects small, intra-familial outbreaks. This study examined intra-household transmission of gastroenteritis using prospectively collected data from 2811 participants (600 households) in a community-based study. There were 258 household clusters of gastroenteritis during the 15 months of observation involving 774 residents (28% of total). Age <6 years and attendance at a day care/kindergarten were associated with increased likelihood of inclusion in a cluster. The reach of illness into the household was extensive, with 63% of household members affected by symptoms during clusters. Simultaneous and secondary transmission of gastroenteritis appeared equally common. In only 20% of clusters did more than one member submit a faecal specimen. Of clusters where two or more specimens were submitted, concordance in laboratory confirmation of pathogens was 18·8%. Our results show that clustering of gastrointestinal symptoms within households occurs commonly, but reliance on pathogen notification data will substantially underestimate the true frequency of gastroenteritis clusters.

The usefulness of the complement-fixation test in differential diagnosis between vesicular stomatitis and foot-and-mouth disease has been demonstrated on two ‘field’ specimens of virus from Mexico. Examples are given of the practical applications of the other methods for this differential diagnosis.

The cell membrane of Mycoplasma gallisepticum was isolated by lysing the cells with digitonin. Chemical and density-gradient analyses and electron microscopy showed the isolated membranes to be relatively free of cytoplasmic contaminants. The density of the membranes exceeded that of other mycoplasma membranes, indicating a higher protein content. Small vesicular extensions seen in the sectioned membranes were interpreted as empty blebs.

The isolated membranes, but not the cytoplasmic fraction, elicited in chickens the production of growth-inhibiting, agglutinating and haemagglutination-inhibition antibodies to M. gallisepticum in titres resembling those obtained by injection of whole cells. The peak of the serological response varied with the serological test employed. The rapid slide-agglutination test became positive as early as 3 days after the first injection of only 50 μg. of membrane protein. The haemagglutination-inhibition antibody titre reached its peak at about 10 days after the first injection, while that of the growth-inhibiting antibodies was reached only at about 25 days. The addition of adjuvant to the membrane antigen did not improve the production of the growth-inhibiting antibodies in chickens, but it produced some improvement in rabbits. Our results support the thesis that the chief immunogens of M. gallisepticum reside in the cell membrane of this organism.

Our knowledge of the antigens of the typhoid bacillus has recently been enlarged by the investigations of Felix & Pitt (1934).

It has been recognized that the Vi antigen, newly established by these workers, is not only a very important factor in immunity, but also apparently a more labile substance than the O antigen hitherto regarded as the portion of the typhoid soma vitally concerned with the production of prophylactic immunity.

Haemagglutination inhibition (HI) antibodies against the influenza viruses A/Hong Kong/8/68 (H3N2) and B/Nederland/77/66 were determined in 420 paired sera from mothers and newborns (umbilical cord sera), sampled in 1970–1.

A higher concentration of antibodies against influenza A virus was found more frequently in neonatal than in maternal sera. By contrast, low titres against influenza B virus were more frequently observed in neonatal than in maternal sera. Maternal age, duration of pregnancy, and birth-weight did not affect the results of the tests.

It is suggested that the titre of the newborn against an epidemic influenza virus can be predicted from that of the mother. Furthermore, the maternal titre may be an indication of the susceptibility of the newborn infant to influenza infections.

The food court at a shopping mall is a potential transfer point for pathogenic microbes, but to date, this environment has not been the subject of detailed molecular microbiological study. We used a combination of culture-based and culture-independent approaches to investigate the types and numbers of bacteria present on food court tables, and on a food court cleaning cloth. Bacteria were found at 102–105 c.f.u./m2 on food court tables and 1010 c.f.u./m2 on the cleaning cloth. Tag-pyrosequencing of amplified 16S rRNA genes revealed that the dominant bacterial types on the cleaning cloth were genera known to include pathogenic species (Stenotrophomonas, Aeromonas), and that these genera were also evident at lower levels on table surfaces, suggesting possible cross-contamination. The evidence suggests a public health threat is posed by bacteria in the food court, and that this may be due to cross-contamination between cleaning equipment and table surfaces.

This is a review of existing data on the burden of shigellosis in Thailand to determine trends, vulnerable groups, predominant species and serotypes, and antimicrobial resistance patterns. Diarrhoea and dysentery morbidity and mortality data from 1991 to 1999 was collected from the routine surveillance system and demographic data from the government census. International and local literature published between 1988 and 2000 was systematically reviewed. Based on the routine surveillance system, the annual incidence of bacillary dysentery decreased from 1·3 to 0·2/10000 persons per year. The remaining burden is highest in children <5 years of age at 2·7/10000 persons per year. In comparison, a prospective study utilizing active surveillance found an incidence in children <5 years of age that was more than 100-fold higher at 640/10000 persons per year. Despite the decrease in morbidity and mortality based on routinely collected data, shigellosis remains an important problem in children <5 years of age in Thailand.

Significant ethnic and socio-economic disparities exist in infectious diseases (IDs) rates in New Zealand, so accurate measures of these characteristics are required. This study compared methods of ascribing ethnicity and socio-economic status. Children in the Growing Up in New Zealand longitudinal cohort were ascribed to self-prioritised, total response and single-combined ethnic groups. Socio-economic status was measured using household income, and both census-derived and survey-derived deprivation indices. Rates of ID hospitalisation were compared using linked administrative data. Self-prioritised ethnicity was simplest to use. Total response accounted for mixed ethnicity and allowed overlap between groups. Single-combined ethnicity required aggregation of small groups to maintain power but offered greater detail. Regardless of the method used, Māori and Pacific children, and children in the most socio-economically deprived households had a greater risk of ID hospitalisation. Risk differences between self-prioritised and total response methods were not significant for Māori and Pacific children but single-combined ethnicity revealed a diversity of risk within these groups. Household income was affected by non-random missing data. The census-derived deprivation index offered a high level of completeness with some risk of multicollinearity and concerns regarding the ecological fallacy. The survey-derived index required extra questions but was acceptable to participants and provided individualised data. Based on these results, the use of single-combined ethnicity and an individualised survey-derived index of deprivation are recommended where sample size and data structure allow it.

National health statistics report a 2·5-fold increase in laboratory-confirmed Chlamydia trachomatis (CT) cases over the last decade in Switzerland where no CT screening programme exists. We obtained essential denominator information to describe the epidemiology of CT in the canton of Basel-Stadt, an urban canton in north-western Switzerland. Laboratories reporting at least two CT infections from Basel-Stadt residents to the SFOPH in 2010 provided demographic and test-related data. CT positivity rates were calculated for 2002–2010. The influences of test year, age, sex and laboratory on CT positivity were investigated in a multivariable model. Positivity differed between sexes and age groups. In our sample of 32 034 records, female and male CT positivity rates were 4·7% and 11·1%, respectively. Test year was significantly associated with test outcome in the multivariable analysis but no time trend was observed. CT positivity did not change over the past 9 years in Basel-Stadt. In contrast to other European countries without CT screening, we found no evidence that the observed increase of Chlamydia cases in the national notification system represents an epidemiological trend, but rather results from an increased testing frequency.

Temperature has a profound influence on the rate at which changes appear in a carcase. A very low temperature indefinitely postpones the apparent changes.

The optimum temperature seems to coincide with that which is most suitable to the activities of ferments and bacteria present in the living body. Alterations in temperature, such as occur in exposed carcases, during the day and night, probably influence putrefaction by their effects on bacterial activity, antagonism, and symbiosis. Variations in temperature conditions may produce changes more profound than would appear likely on superficial consideration. The optimum temperature for one group of organisms is different from the optimum conditions for another. Changes in temperature, therefore, especially if they are of some duration, are apt to favour some groups at the expense of others, and influence in this way the whole sequence of subsequent events.

Water is necessary to the growth of bacteria. It permits of their migration in the tissues, allows their ferments to act, distributes by diffusion the substances on which they live, and dilutes the toxic products of their activity.

The effects of temperature and moisture cannot be dissociated for it is in combination that these factors exert their greatest influence.

In a hot dry atmosphere the removal of water by evaporation may be so rapid that a small carcase may become desiccated before putrefaction has advanced far. In hot arid countries a variety of influences inimical to putrefaction are at work, especially when carcases are resting on dry sand. The strong sunlight tends to destroy the skin organisms, which we believe to be the most important agents in producing putrefaction. The skin soon becomes horny in consistency, imprisoning the organisms within it, and preventing their invasion of the tissues. The horny skin protects the carcases from moisture from any source, and the exudation of fluid finally results in mummification.

In a hot moist atmosphere sunlight is robbed of much of its bactericidal power, and the conditions most favourable to putrefaction prevail. Moisture from the air, rain water and water from the ground are absorbed and keep the skin moist. Suitable conditions for the growth and penetration of skin and soil organisms are thus created. Very soon the superficial layers of the epidermis are loosened and the sodden skin permits the autolytic enzymes, passing from the deeper parts, to exert their action on it and assist the putrefactive organisms. The aerobic conditions now prevailing in the skin aid disintegration. The protective influence of the skin is thus lost, and water has free access to the underlying tissues, where it exerts its elutriating and solvent effects. The products of putrefaction are diluted and removed and the dissemination of organisms favoured. Oxidation now plays some part in the process and disintegration proceeds rapidly. The presence of maggots seems to hasten putrefaction.

Such considerations ought to be sufficient to suggest the inadvisability of treating decomposing animal matter with watery solutions of antiseptics as is so often done. Here we may point out that the flesh can be completely macerated from the bones in six days, if a carcase is kept in water at 37° F. The progress is especially rapid, if the water is changed after three days, and the products which seem to inhibit bacterial growth removed.

Within a few days of death, the time varying with the conditions, certain phenomena are noticed if a carcase is kept under observation. It becomes distended with gas, fluid exudes from it, and the skin over certain areas becomes green. These phenomena are usually regarded as evidences of putrefaction. Since in properly treated carcases they are not followed by disintegration of the proteins, which form the main constituents of the body, and since they appear to be due partly to enzyme action and partly to the action of intestinal bacteria of the colon-type on such constituents as carbohydrates, and not to the action of putrefactive organisms, we consider that we are justified in regarding these phenomena as precursors of true putrefactive changes. By the latter term we understand the disintegration of the tissues by putrefactive organisms, a process accompanied by the elimination of foul-smelling products.

The evidence on which this conclusion is based has been given in detail in this section, and here we propose to discuss only the more important considerations.

In developed countries the majority of hepatitis C virus (HCV) infections occur in injecting drug users (IDUs) with prevalence in IDUs often high, but with wide geographical differences within countries. Estimates of local prevalence are needed for planning services for IDUs, but it is not practical to conduct HCV seroprevalence surveys in all areas. In this study survey data from IDUs attending specialist services were collected in 52/149 sites in England between 2006 and 2008. Spatially correlated random-effects models were used to estimate HCV prevalence for all sites, using auxiliary data to aid prediction. Estimates ranged from 14% to 82%, with larger cities, London and the North West having the highest HCV prevalence. The methods used generated robust estimates for each area, with a well-identified spatial pattern that improved predictions. Such models may be of use in other areas of study where surveillance data are sparse.

Historical outbreaks can be an important source of information in the understanding of norovirus evolution and epidemiology. Here, we revisit an outbreak of undiagnosed gastroenteritis that occurred in Shippensburg, Pennsylvania in 1972. Nearly 5000 people fell ill over the course of 10 days. Symptoms included diarrhea, vomiting, stomach cramps, and fever, lasting for a median of 24 h. Using current techniques, including next-generation sequencing of full-length viral genomic amplicons, we identified an unusual norovirus recombinant (GII.Pg/GII.3) in nine of 15 available stool samples from the outbreak. This particular recombinant virus has not been reported in recent decades, although GII.3 and GII.Pg genotypes have been detected individually in current epidemic strains. The consensus nucleotide sequences were nearly identical among the four viral genomes analysed, although each strain had three to seven positions in the genome with heterogenous non-synonymous nucleotide subpopulations. Two of these resulting amino acid polymorphisms were conserved in frequency among all four cases, consistent with common source exposure and successful transmission of a mixed viral population. Continued investigation of variant nucleotide populations and recombination events among ancestral norovirus strains such as the Shippensburg virus may provide unique insight into the origin of contemporary strains.

Healthcare-associated infections (HAIs) are a major worldwide public-health problem, but less data are available on the long-term trends of HAIs and antimicrobial use in Eastern China. This study describes the prevalence and long-term trends of HAIs and antimicrobial use in a tertiary care teaching hospital in Hefei, Anhui, China from 2010 to 2017 based on annual point-prevalence surveys. A total of 12 505 inpatients were included; 600 HAIs were recorded in 533 patients, with an overall prevalence of 4.26% and a frequency of 4.80%. No evidence was found for an increasing or decreasing trend in prevalence of HAI over 8 years (trend χ2 = 2.15, P = 0.143). However, significant differences in prevalence of HAI were evident between the surveys (χ2 = 21.14, P < 0.001). The intensive care unit had the highest frequency of HAIs (24.36%) and respiratory tract infections accounted for 62.50% of all cases; Escherichia coli was the most common pathogen (16.67%). A 44.13% prevalence of antimicrobial use with a gradually decreasing trend over time was recorded. More attention should be paid to potential high-risk clinical departments and HAI types with further enhancement of rational antimicrobial use.

Fever is a common adverse event following measles vaccination, more frequent among older children and those receiving Measles-Mumps-Rubella-Varicella vaccine vs. Measles-Mumps-Rubella vaccine, two factors associated with a better antibody response. However, the role of fever in the immunogenicity of measles-containing vaccines (MCV) is unclear. We performed a post-hoc pooled analysis of data of 5 216 11 to 22 month-old children receiving MCV from 2004 to 2012 in Europe and USA to evaluate the association between post-immunisation fever and antibody response, measured by geometric mean concentrations (GMCs). We further evaluated fever as an effect modifier or a mediator in the associations between the type of MCV or the age at first vaccination and vaccine immunogenicity. After the first dose, fever was associated with 60% higher GMCs (95% CI 1.51–1.68). For children vaccinated at ⩾12 months, the fever did not modify and minimally mediated (2% to 3%) the association between age and antibody response. Fever mediated 18% of the association between type of MCV and GMCs. In a model including fever, age and type of vaccine, fever was the strongest predictor of GMCs. These results suggest that fever is associated with a stronger measles antibody response independently of age and type of MCV.

This study describes risk factors associated with mortality among COVID-19 cases reported in the WHO African region between 21 March and 31 October 2020. Average hazard ratios of death were calculated using weighted Cox regression as well as median time to death for key risk factors. We included 46 870 confirmed cases reported by eight Member States in the region. The overall incidence was 20.06 per 100 000, with a total of 803 deaths and a total observation time of 3 959 874 person-days. Male sex (aHR 1.54 (95% CI 1.31–1.81); P < 0.001), older age (aHR 1.08 (95% CI 1.07–1.08); P < 0.001), persons who lived in a capital city (aHR 1.42 (95% CI 1.22–1.65); P < 0.001) and those with one or more comorbidity (aHR 36.37 (95% CI 20.26–65.27); P < 0.001) had a higher hazard of death. Being a healthcare worker reduced the average hazard of death by 40% (aHR 0.59 (95% CI 0.37–0.93); P = 0.024). Time to death was significantly less for persons ≥60 years (P = 0.038) and persons residing in capital cities (P < 0.001). The African region has COVID-19-related mortality similar to that of other regions, and is likely underestimated. Similar risk factors contribute to COVID-19-associated mortality as identified in other regions.

Orthobunyaviruses, tri-segmented, negative-sense RNA viruses, have long been associated with mild to severe human disease in Africa, but not haemorrhagic fever. However, during a Rift Valley fever outbreak in East Africa in 1997–1998, Ngari virus was isolated from two patients and antibody detected in several others with haemorrhagic fever. The isolates were used to identify Ngari virus as a natural Orthobunyavirus reassortant. Despite their potential to reassort and cause severe human disease, characterization of orthobunyaviruses is hampered by paucity of genetic sequences. Our objective was to obtain complete gene sequences of two Bunyamwera virus and three Ngari virus isolates from recent surveys in Kenya and to determine their phylogenetic positioning within the Bunyamwera serogroup. Newly sequenced Kenyan Bunyamwera virus isolates clustered closest to a Bunyamwera virus isolate from the same locality and a Central African Republic isolate indicating that similar strains may be circulating regionally. Recent Kenyan Ngari isolates were closest to the Ngari isolates associated with the 1997–1998 haemorrhagic fever outbreak. We observed a temporal/geographical relationship among Ngari isolates in all three gene segments suggesting a geographical/temporal association with genetic diversity. These sequences in addition to earlier sequences can be used for future analyses of this neglected but potentially deadly group of viruses.