Viraemia is an important aspect of the pathogenesis of infectious diseases, but the mechanisms of entry and removal of virus from the vascular system particularly in natural hosts are poorly understood. The results of this study showed that the clearance of foot and mouth disease virus (FMDV) from the circulation of cattle and goats followed the general rules for the clearance of inert particulate materials and other viruses from the circulation. High doses of infused FMDV were cleared less efficiently than low doses, probably as a result of a depletion of the reticulo-endothelial system by the higher doses. FMDV was cleared from the circulation of cattle at a considerably slower rate than from the circulation of goats, but in both species significant individual variation in clearance was observed. These results could explain individual as well as species variations relative to the onset and duration of viraemia.

On 30 May 2006, township S in Sichuan Province, China, reported an outbreak of hepatitis A (HA) in students who had recently received HA vaccine. The concern was raised that the vaccine had caused the outbreak. We attempted to identify the source of infection and mode of transmission. A HA case was defined as onset of jaundice or anorexia since 1 April 2006 with a twofold elevation of alanine aminotransferase (ALT) and anti-HA virus-IgM in a resident of or visitor to the township. Exposures to vaccine and snacks of 90 case-students to those of 107 control-students were compared. Thirty-four per cent of cases ate ice slush compared to 4·7% of controls (OR 4·1), and 51% of cases ate snow cones compared to 17% of controls (OR 8·3). The ice snacks were made with well water. HA virus RNA was detected by reverse transcription–polymerase chain reaction from patients' blood and well water. Untreated well water poses important dangers to the public in areas where piped, potable water is available.

In autumn 2014, enterovirus D68 (EV-D68) cases presenting with severe respiratory or neurological disease were described in countries worldwide. To describe the epidemiology and virological characteristics of EV-D68 in England, we collected clinical information on laboratory-confirmed EV-D68 cases detected in secondary care (hospitals), between September 2014 and January 2015. In primary care (general practitioners), respiratory swabs collected (September 2013–January 2015) from patients presenting with influenza-like illness were tested for EV-D68. In secondary care 55 EV-D68 cases were detected. Among those, 45 cases had clinical information available and 89% (40/45) presented with severe respiratory symptoms. Detection of EV-D68 among patients in primary care increased from 0.4% (4/1074; 95% CI 0.1–1.0) (September 2013–January 2014) to 0.8% (11/1359; 95% CI 0.4–1.5) (September 2014–January 2015). Characterization of EV-D68 strains circulating in England since 2012 and up to winter 2014/2015 indicated that those strains were genetically similar to those detected in 2014 in USA. We recommend reinforcing enterovirus surveillance through screening respiratory samples of suspected cases.

Natural immunity to Haemophilus influenzae type b (Hib) invasive disease is based on antibodies arising in response to encounters with Hib or cross-reactive (CR) bacteria. The relative importance of Hib and CR contacts is unknown. We applied a statistical model to estimate the total rate of immunizing infections of Hib and CR prior to wide-scale vaccinations in Finland and the UK. The average rates of these contacts were 0.7 and 1.2 per year per child in Finland and the UK, respectively. Using a rough estimate of 0.1 Hib acquisitions per year per child in the UK based on carriage rates, the proportion of Hib among all immunizing contacts was in the order of 10%, suggesting that CR bacteria have a major role. In general, varying frequency of CR contacts may explain some differences in the pre-vaccination incidence and age-distribution of invasive disease in different countries.

Long-chain fatty acids are not appreciably bactericidal to tubercle bacilli at neutral pH, but become so even in slightly acid solution. In this way tubercle bacilli, normally resistant to 0·1 N hydrochloric acid (pH 1·0), are rapidly killed at this pH if traces of fatty acid are present, such as can be found inside test tubes that have been plugged with cotton wool and sterilized by dry heat.

The lethal effect is largely prevented by non-ionic, cationic, and to a lesser extent anionic detergents, which probably take up the fatty acid into the micelles so that it can no longer attack the bacilli.

The various fatty acids identified in the deposit from heated cotton wool were tested individually and found to be bactericidal. They comprised the usual C12 to C18 saturated acids and also oleic acid. The latter, however, showed no particular lethal toxicity in excess of that shown by, for example, palmitic acid. Shorter chained fatty acids than those represented in the deposit were less lethal.

We wish to thank Dr A. T. James for the chromatographic analyses and for advice; Dr R. J. W. Rees for carrying out counts of total acid-fast bacilli in two experiments; Messrs. Robinson & Sons Ltd, Chesterfield, for information on the industrial processes involved in the preparation of cotton wool; Mr E. J. Latham for advice on preparing glassware; and Dr J. Marks for helpful criticism of the manuscript.

The antibiotic susceptibility pattern of Vibrio cholerae O139, Bengal, an emerging intestinal pathogen has been determined by the Kirby Bauer technique and the MIC values of some antibiotics against these strains by agar dilution technique. All the strains were susceptible to tetracycline, norfloxacin, ciprofloxacin and a majority was susceptible to gentamicin (95·7%) and nalidixic acid (82·9%). Only 51% were susceptible to cefotaxime and most strains were resistant to furazolidone (95·7%), ampicillin (87·3%) and co-trimoxazole (91·5%). The study shows the importance of judicious use of antibiotics in cholera cases and the need for monitoring the susceptibility status of these strains particularly because of their ability to cause extra-intestinal infections like septicaemia.

Staphylococcus aureus strains of type 95 in Denmark have increased to a frequency of 20% of the total S. aureus population. A clonal origin and possible subdivision of these strains have been discussed. In the present investigation 35 epidemiologically unrelated S. aureus strains of type 95 as well as reference strains of other types have been analysed by other typing techniques including lectintyping, multilocus enzyme electrophoresis and pulsed-field gel electrophoresis of genomic restriction fragments. No subdivision could be achieved based on any of these methods and a clonal origin seems therefore possible.

Helicobacter pylori (H. pylori) is present in the stomach of half of the world's population. The force of infection describes the rate at which susceptibles acquire infection. In this article, we estimated the age-specific force of infection of H. pylori in Mexico. Data came from a national H. pylori seroepidemiology survey collected in Mexico in 1987–88. We modelled the number of individuals with H. pylori at a given age as a binomial random variable. We assumed that the cumulative risk of infection by a given age follows a modified exponential catalytic model, allowing some fraction of the population to remain uninfected. The cumulative risk of infection was modelled for each state in Mexico and were shrunk towards the overall national cumulative risk curve using Bayesian hierarchical models. The proportion of the population that can be infected (i.e. susceptible population) is 85.9% (95% credible interval (CR) 84.3%–87.5%). The constant rate of infection per year of age among the susceptible population is 0.092 (95% CR 0.084–0.100). The estimated force of infection was highest at birth 0.079 (95% CR 0.071–0.087) decreasing to zero as age increases. This Bayesian hierarchical model allows stable estimation of state-specific force of infection by pooling information between the states, resulting in more realistic estimates.

Experiments were made to find out whether the common communion cup is likely to serve as a vehicle for the transmission of infection.

A silver chalice and sacramental wine containing 14·5% of alcohol were used. Observations with volunteers showed that the number of organisms deposited on the rim of the chalice varied from person to person, but was usually quite small—less than 100.

Rotation of the cup was of no benefit except to those partaking during the first round, since the saliva deposited on the rim by each person in turn remained to contaminate the cup during the second round, and the combined effect of the alcohol and the silver of the chalice was not rapid enough to destroy the contaminating organisms before rotation of the cup was completed.

On the other hand the use of a linen cloth or purificator led to a diminution of about 90% in the bacterial count of the cup.

Organisms in saliva deposited on the interior of the dry chalice suffered some diminution in numbers within 8 min., presumably as the result of the disinfectant action of the silver, but the effect was too small to be of significance.

When suspended in wine and deposited on the internal surface of the chalice Escherichia coli suffered a substantial reduction within 3 min., Streptococcus pyogenes was destroyed completely; but Staphylococcus aureus was affected to a much less extent.

Various experiments designed to measure the disinfectant action of wine, and of silver and wine together, showed that the augmenting effect of silver on the disinfectant action of the alcohol was quite small. Strep. pyogenes proved to be far more sensitive to alcohol than Esch. coli, Staph. aureus and Serratia marcescens. Under the conditions of the experiment these last three organisms were not destroyed for 10–12 min., whereas Strep. pyogenes perished within 1½ min.

The results of our work are in general agreement with those of previous workers, and show that the organisms deposited on the rim of the communion cup are not destroyed within the short time—5 sec. as an average—elapsing between the partaking of the sacrament by each successive communicant.

It must therefore be admitted that the common communion cup may serve as a means of transmitting infection. Reasons are given, however, for believing that the risk of transmission is very small, and probably much smaller than that of contracting infection by other methods in any gathering of people.

Such risk as there is could be greatly diminished by the use of a purificator for wiping the cup between each communicant, and could be abolished completely by substituting individual cups or by the practice of intinction.

Hepatitis E virus (HEV) is a well-known cause of acute hepatitis. Immunocompromised subjects, including liver transplant recipients, are considered to be at risk for HEV infection, which occasionally follows a chronic course. The diagnosis of HEV infection in these patients must be based on HEV RNA testing, as serology has variable performance. The aim of this study was to assess the prevalence of HEV infection in liver transplant recipients in Greece by means of HEV RNA testing. Liver transplant recipients followed in the sole transplant centre in Greece were prospectively included. HEV RNA was detected by real-time RT-PCR. Positive samples were further analysed using a nested reverse transcription RT-PCR kit, which amplifies a 137-nucleotide sequence within the ORF2/ORF3 overlapping region to detect the HEV genotype and perform phylogenetic analysis. The mean age of the included patients (n = 76) was 54 years. The most common indication for liver transplantation was viral hepatitis (57%). The majority of the patients (75%) received a calcineurin inhibitor as part of their immunosuppressive regimen and had normal liver enzymes. HEV RNA was found positive in only 1/76 (1.3%) patient. Phylogenetic analysis showed that the sequence clustered into the HEV genotype 3 clade. This patient experienced an acute hepatitis flare, which nonetheless did not become chronic. The prevalence of HEV infection in liver transplant recipients in Greece is similar (1.3%) to that reported previously in other countries. Transplant physicians should be aware of this condition and its associated consequences.

The aim of this study was to investigate the optimal pertussis booster vaccination strategy for The Netherlands. A realistic age-structured deterministic model was designed. Assuming a steady-state situation and correcting for underreporting, the model was calibrated using notification data from the period 1996–2000. Several sensitivity analyses were performed to explore the impact of different assumptions for parameters surrounded by uncertainty (e.g. duration of protection after natural infection, underreporting factors, and transmission probabilities). The optimal age of an additional booster dose is in the range of 10–15 years, and implementation of this booster dose will reduce both symptomatic and asymptomatic infections, although the incidence of symptomatic infections in older age groups will increase. The impact of the different assumptions used in the model was in general limited. We conclude that over a wide range of assumptions, an additional booster dose can reduce the incidence of pertussis in the population.

Expansion of sandflies and increasing pet travel have raised concerns about canine leishmaniasis (CanL) spread to new areas of Europe. This study aimed to estimate the probability of CanL introduction and persistence following movements of infected dogs. Stochastic modelling was used to estimate the probabilities of (1) CanL infection during travels or imports of infected dogs (Pinf and PinfCA, respectively), (2) CanL persistence in a dog network with sandflies after introduction of an infected dog (Pper), and (3) persistence in a CanL-free region (Pper region) for N dogs moving between endemic and free regions. Different mitigation measures (MMs) were assessed. Pinf [7·8%, 95% predictive interval (PI) 2·6–16·4] and Pper (72·0%, 95% PI 67·8–76·0) were reduced by use of repellent, vaccine, prophylactic medication, and insecticide, in decreasing order of effectiveness. Testing and exclusion of positive dogs was most effective in reducing Pper region for a small N. The spread of CanL to CanL-free areas with sandflies is thus likely, but can be reduced by MMs.

Much of our current understanding about novel coronavirus disease 2019 (COVID-19) comes from hospitalised patients. However, the spectrum of mild and subclinical disease has implications for population-level screening and control. Forty-nine participants were recruited from a group of 99 adults repatriated from a cruise ship with a high incidence of COVID-19. Respiratory and rectal swabs were tested by polymerase chain reaction (PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Sera were tested for anti-SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA) and microneutralisation assay. Symptoms, viral shedding and antibody response were examined. Forty-five participants (92%) were considered cases based on either positive PCR or positive ELISA for immunoglobulin G. Forty-two percent of cases were asymptomatic. Only 15% of symptomatic cases reported fever. Serial respiratory and rectal swabs were positive for 10% and 5% of participants respectively about 3 weeks after median symptom onset. Cycle threshold values were high (range 31–45). Attempts to isolate live virus were unsuccessful. The presence of symptoms was not associated with demographics, comorbidities or antibody response. In closed settings, incidence of COVID-19 could be almost double that suggested by symptom-based screening. Serology may be useful in diagnosis of mild disease and in aiding public health investigations.

The characters of the Aronson Streptococcus from Prof. Neufeld's laboratory at the “Robert Koch” Institute in Berlin have been described. This coccus resembles the pneumococcus in many respects, viz. the appearance of the colonies on the surface of horse blood agar, its virulence and capsule production in mice and rabbits, the production of a specific precipitable substance in the peritoneal washings of infected mice, the formation of firm clumps and masses when mixed with homologous antiserum, the ease of production of active and passive immunity in mice and rabbits by intraperitoneal and intravenous inoculation, the alteration in the morphology of colonies, i.e. the appearance of R forms, associated with attenuation of virulence. It differs from the pneumococcus in the following features: the round shape of the cocci, bile-insolubility and the absence of autolysis in surface colonies, the beta haemolysis of deep colonies in horse blood agar, the production of a soluble haemolysin in broth cultures, the difficulty of producing active immunity in mice by the subcutaneous injection of heat-killed vaccines.

I have obtained the Aronson Streptococcus (Neufeld type), which Lance-field places in a group containing chiefly streptococci of bovine origin, from human throats, but there was no evidence in any instance that it was producing disease, and it seems probable that it is not pathogenic for man.

The results of my investigation of this strain are in agreement with those of Yoshioka (1923), Killian (1924) and Lancefield (1933, 1934).

There are in existence other laboratory strains designated Aronson Streptococcus. These have been found to exhibit specific characters identifying them with the Str. pyogenes. It is proposed that the name Streptococcus Aronson should be confined to strains possessing the characters of Aronson N above described.

Despite a long history of dog-transmitted human rabies outbreaks in Liberia, West Africa, no reports exist of molecular characterisation of the causative lyssaviruses. This study investigated Rabies lyssavirus (RABV) strains isolated at the dog–human interface in Monrovia, Liberia 2016 and 2017, by reverse transcription polymerase chain reaction, using primers specific for the nucleoprotein (N) gene. Out of 20 specimens (19 dog brain samples and one human saliva) tested as suspected rabies cases, three (15%) were positive. Purified amplicons from all three positive specimens were sequenced in both forward and reverse directions. Phylogenetic analysis was conducted in MEGA7 and PhyML3 to determine their relationship with RABV sequences accessioned in NCBI GenBank. The first of three RABV strains detected clustered with China lineage 2 RABVs of dogs (99% homology to KU963489 and DQ666322). The second strain segregated with Africa lineage 2 RABVs also of dog origin, and the third strain segregated with Africa lineage 3 RABVs of Southern Africa viverrids. Our results show a transcontinental strain of rabies virus co-circulating with Africa lineages in post-conflict Liberia. This finding should stimulate more effective sub-regional planning and execution of one-health actions, towards stepwise surveillance and elimination of rabies in West Africa by 2030.

We investigated and quantified the factors which may affect the prevalence of cystic echinococcosis caused by Echinococcus granulosus in Rangtang County using a multidisciplinary approach. From a previously performed field survey, epidemiological data were linked with environmental data. Altitude and land surface temperature were extracted from remote-sensing images. Cumulative logistic regression models were used to identify and quantify the potential risk factors. The multiple regression models confirmed that yaks (χ 2 = 4·0447, P = 0·0443), dogs (χ 2 = 8·3455, P = 0·0039) and altitude (χ2 = 7·6223, P = 0·0058) were positively correlated with the prevalence of cystic echinococcosis, while land surface temperature may have a negative association. The findings showed that dogs and yaks play the most important role in the transmission of cystic echinococcosis, while altitude and land surface temperature may also be involved in the transmission.

Four series of tests, A, B, C and D, have been considered in detail. In the first two series, to obtain the values of the ImD 50, percentages of survivors were transformed into probits, and the best-fitting straight lines connecting the probits with the logarithms of the doses were obtained by the method of maximum likelihood. This is the most accurate method to use. These results showed that the error of the test was large, but there were no significant differences in the slope of the probitlog dose relation in the results of tests from any one laboratory. The slope (1·46 ± 0·09) obtained from series A was greater than that from series B (0·79 ± 0·06). with a consequent increase in accuracy.

In 2013–2014, the Public Health Agency of Sweden developed a web-based participatory surveillance system, Hӓlsorapport, based on a random sample of individuals reporting symptoms weekly online, to estimate the community incidence of self-reported acute gastrointestinal (AGI), acute respiratory (ARI) and influenza-like (ILI) illnesses and their severity. We evaluated Hӓlsorapport's acceptability, completeness, representativeness and its data correlation with other surveillance data. We calculated response proportions and Spearman correlation coefficients (r) between (i) incidence of illnesses in Hӓlsorapport and (ii) proportions of specific search terms to medical-advice website and reasons for calling a medical advice hotline. Of 34 748 invitees, 3245 (9·3%) joined the cohort. Participants answered 81% (139 013) of the weekly questionnaires and 90% (16 351) of follow-up questionnaires. AGI incidence correlated with searches on winter-vomiting disease [r = 0·81, 95% confidence interval (CI) 0·69–0·89], and ARI incidence correlated with searches on cough (r = 0·77, 95% CI 0·62–0·86). ILI incidence correlated with the web query-based estimated incidence of ILI patients consulting physicians (r = 0·63, 95% CI 0·42–0·77). The high response to different questionnaires and the correlation with other syndromic surveillance systems suggest that Hӓlsorapport offers a reasonable representation of AGI, ARI and ILI patterns in the community and can complement traditional and syndromic surveillance systems to estimate their burden in the community.

In a survey undertaken in an intensive care unit, coliform bacilli were found to be responsible for most infections, Pseudomonas aeruginosa and Staphylococcus aureus being isolated much less frequently. Tracheostomy or endotracheal intubation predisposed to infection, but in our experience intermittent positive pressure ventilation did not significantly affect its incidence. Little cross-infection has occurred, and it has never been possible to incriminate the ventilators in its transmission.

We gratefully acknowledge the assistance we have received from colleagues in the Intensive Therapy Unit and the Department of Bacteriology during the course of this investigation.

We report a molecular epidemiological study of rabies virus (RABV) strains circulating in animal populations in Bhutan, and investigate potential origins of these viruses. Twenty-three RABV isolates originating from dogs and other domestic animals were characterized by sequencing the partial nucleoprotein (N) gene (395 bp). Phylogenetic analysis was conducted and the Bhutanese isolates were compared with rabies viruses originating from other parts of the world. Phylogenetic analysis showed that Bhutanese isolates were highly similar and were closely related to Indian strains and South Asian Arctic-like-1 viruses. Our study suggests that the rabies viruses spreading in southern parts of Bhutan have originated from a common ancestor, perhaps from the Indian virus strain.