1. For the particular toxin tested, the intravenous m.l.d. for mice was 60 times and the intramuscular m.l.d. for mice 100 times, the guinea-pig sub cutaneous m.l.d.

2. Antitoxin has the same neutralising power for toxin in mice as in guinea-pigs.

Early investigation of travel-related cases in an outbreak of an emerging infectious disease can provide useful information to epidemiologists to characterize the exposure, while they may differ in demographic profiles from cases reported in the country where the outbreak has occurred. During the spring 2011 E. coli outbreak in Germany, we proposed a methodological approach to collect a minimal set of demographic and clinical data that are relatively easy to obtain and available at an early stage of an outbreak investigation. Ninety-eight STEC O104 travel-related cases were reported in a survey by seven EU countries, Switzerland, Canada and the USA. We found a mean incubation period (n = 50) of 8·5 days, which confirmed previous estimations communicated by the Robert Koch Institute. No significant association was found between the duration of the incubation period and possible demographic and clinical factors, although the older the age, the shorter the incubation period that was observed. Such approach and observations are informative for further investigations of outbreaks of enterohaemorrhagic E. coli or other emerging infectious diseases.

A reassortant swine-origin A(H3N2) virus (A/swine/BinhDuong/03-9/2010) was detected through swine surveillance programmes in southern Vietnam in 2010. This virus contains haemagglutinin and neuraminidase genes from a human A(H3N2) virus circulating around 2004–2006, and the internal genes from triple-reassortant swine influenza A viruses (IAVs). To assess population susceptibility to this virus we measured haemagglutination inhibiting (HI) titres to A/swine/BinhDuong/03-9/2010 and to seasonal A/Perth/16/2009 for 947 sera collected from urban and rural Vietnamese people during 2011–2012. Seroprevalence (HI ⩾ 40) was high and similar for both viruses, with 62·6% [95% confidence interval (CI) 59·4–65·7] against A/Perth/16/2009 and 54·6% (95% CI 51·4–57·8%) against A/swine/BinhDuong/03-9/2010, and no significant differences between urban and rural participants. Children aged <5 years lacked antibodies to the swine origin H3 virus despite high seroprevalence for A/Perth/16/2009. These results reveal vulnerability to infection to this contemporary swine IAV in children aged <5 years; however, cross-reactive immunity in adults would likely limit epidemic emergence potential.

THe experiments recorded here were initiated following upon the occurrence in this country of foot-and-mouth disease in a cow, which a short time previously had been injected for the purpose of inducing oestrus with a pituitary extract imported from the Continent. Mr D. A. E. Cabot, M.R.C.V.S., Chief Veterinary Officer of the Ministry of Agriculture, made reference to this interesting case in a discussion on foot-and-mouth disease at the First Imperial Veterinary Conference held in London (1938). Confirmation of the nature of the infection was obtained by the inoculation of test animals under experimental conditions with suitable material collected from the injected animal. Further investigations were made. Three ampoules containing pituitary extract were obtained from the distributors in London of the imported commercial preparation under discussion. These ampoules belonged to the same batch as the ampoule with the extract from which the cow had been inoculated. Messrs A. Eccles, M.R.C. V.S. and A. M. Graham, M.R.C.V.S., at the Experimental Station of the Foot-and-Mouth Disease Research Committee at Pirbright, tested this material for virus infectivity by the inoculation of cattle and guinea-pigs. They reported that all three samples of pituitary extract were contaminated with the virus of footand-mouth disease. In addition they produced evidence that the immunological type of the virus recovered from the extract in the ampoules was the same as that of the virus recovered from the cow, viz. Vallée and Carré 0. This and additional information left no doubt that the outbreak of the disease had been produced by the inoculation of the pituitary extract, and further that this extract had been prepared from the pituitary glands of cattle, which were very probably in the early stages of infection with foot-and-mouth disease at the time of slaughter.

A carrier has been found of at least three phage types of Salmonella paratyphi B. Investigation has shown that phage-mediated conversion could account for this multiplicity of types according to the following scheme.

It is not possible, however, to exclude the actual occurrence of repeated infection with different phage types.

I am grateful to Dr E. S. Anderson of the Central Enteric Reference Laboratory, Colindale, for his interest and advice during the course of this investigation, and to Dr Helen A. Wright of the University of Edinburgh who provided the many cultures and so introduced me to this problem.

The supernatant fluids of batch and continuous cultures of Brucella strains contained up to 100 mg/i of soluble RNA which could be recovered by precipitation with lysozyme. This RNA fraction had many of the properties of ribosomal RNA and was single-stranded, sensitive to ribonuclease, with an approximate sedimentation constant of 5S, a molecular weight of about 35000 daltons and an adenine; guanine; cytosine; uracil content of 17·5 26·5 33; 23 mol% respectively. RNA fractions from lysozyme precipitates evoked high titres of Brucella agglutinins on injection into rabbits and induced acute inflammatory responses in guinea-pig skin. Highly purified RNA fractions prepared by phenol extraction of lysozyme precipitates did not evoke antibodies to Brucella abortus.

In a recent paper in this Journal by Marshall et al. (1985), which described the bacterial endonuclease DNA analysis (BRENDA) of several Escherichia coli 0126 strains, the following statement was found in the summary: ‘The isolates from the outbreak produced indistinguishable DNA electrophoretic patterns in spite of their assignment to seven different H serotypes… These results support the epidemiological evidence that a single-strain outbreak had occurred, and they cast doubt on the value of H typing for this particular investigation.’ The same 0126 strains that were enterotoxigenic (ST) were treated in two earlier papers (Bettelheim & Reeve, 1982; Bettelheim, 1984) and also on these two earlier occasions the authors raised doubt about the stability of E. coliH typing results.

Any description of the outbreaks of venereal disease is of necessity bound up with the migration of races, or parts of races, with wars and the consequent dislocation of the social system resulting from them. There are many inferences available from current writers showing how this contagious disease was spread and there is a good deal of reason to believe that some, at least, of the numerous cases of “leprosy” for which provision was made on frequent trade routes in past times were really cases of venereal disease.

Recent New Zealand and Australian isolates of Salmonella typhimurium phage type 179 were studied for relatedness by colony incompatibility. This established that all but one strain of the New Zealand groups probably formed a clone despite carrying a variety of plasmids. The Australian strains showed a far greater diversity. This study demonstrates the epidemiological usefulness of the colony incompatibility reactions.

The pathological histology of plague in man and experimental plague in animals has already been the subject of several researches, notably those of Aoyama (1896), Yamagiwa (1897), Albrecht and Gohn (1897), Dürck (1904) and Hamdi (1904) in the case of human plague, and of van der Stricht (1897), Honl (1897), Lustig and Zardo (1897), Babes and Livadite (1897), Albrecht and Gohn (1900) and Sata (1900) in the case of experimental plague.

In a study of the influence of environmental and other conditions on the growth and nutrition of the children of the poorer classes in the city of Glasgow, it seemed desirable to determine how far a homogeneous stock was being dealt with since there was some danger that racial variations might modify the results of the investigation.

The kernel of modelling transmission dynamics of infectious diseases lies in constructing the force of infection (FOI). Traditionally, it was based on mass-action law. In this paper, we show, based on survey data of Escherichia coli O157 infection on Scottish cattle farms, that the actual form of FOI deviates greatly from mass-action law. Further, control effectiveness deviates qualitatively: the epidemic of mass-action FOI can be controlled with a control effort larger than the so-called herd immunity, while the epidemic inferred from the survey data of E. coli O157 infection was shown to be difficult to control. This indicates that, at least for E. coli O157 infection on cattle farms, it is risky to rely on models of transmission dynamics that were based on mass-action law to design the optimal intervention programme for infectious diseases. This suggests the importance of collecting epidemic data and model selection from data-driven models to infer the most likely model of transmission dynamics.

The distribution of serogroups of thermophilic campylobacters isolated in Israel from human patients (2421 isolates), chicken (942), turkeys (158), cattle (398), wild birds (234) and other sources, was studied.

Among the human isolates, 74 ROG-serogroups were identified. The six most commonly isolated of these (1,18; 11; 12; 8,23; 4 and 5,39) were found frequently in chickens. Only four common serogroups in man were also common in cattle, three in turkeys and two in wild birds.

Two common serogroups in man (1,18 and 5,39) were prevalent all over the country, while others were regionally distributed. When the prevalence of different serogroups in Israel was compared to that in Canada, some groups were common to both countries and others were common in only one or the other.

Campylobacter jejuni accounted for 86·7% to 92·1% of the isolates from man, chickens, turkeys, cattle and most of the wild birds. C. coli was found in 34·4% of isolates from cattle egrets and in 70·5% of those from pigs.

Retrospective data evaluated increases in advanced medical support for children with medically attended acute respiratory illness (MAARI) during influenza outbreak periods (IOP). Advanced support included hospitalisation, intensive care unit admission, or mechanical ventilation, for children aged 0–17 years hospitalised in Maryland's 50 acute-care hospitals over 12 influenza seasons. Weekly numbers of positive influenza tests in the Maryland area defined IOP for each season as the fewest consecutive weeks, including the peak week containing at least 85% of positive tests with a 2-week buffer on either side of the IOP. Peak IOP (PIOP) was defined as four consecutive weeks containing the peak week with the most number of positive influenza tests. Off-PIOP was defined as the ‘shoulder’ weeks during each IOP. Non-influenza season (NIS) was the remaining weeks of that study season. Rate ratios of mean daily MAARI-related admissions resulting in advanced medical support outcomes during PIOP or Off-PIOP were compared with the NIS and were significantly elevated for all 12 study seasons combined. The results suggest that influenza outbreaks are associated with increased advanced medical support utilisation by children with MAARI. We feel that this data may help preparedness for severe influenza epidemics or pandemic.

Pneumonia is a leading cause of death in New York City (NYC). We identified spatial clusters of pneumonia-associated hospitalisation for persons residing in NYC, aged ⩾18 years during 2010–2014. We detected pneumonia-associated hospitalisations using an all-payer inpatient dataset. Using geostatistical semivariogram modelling, local Moran's I cluster analyses and χ2 tests, we characterised differences between ‘hot spots’ and ‘cold spots’ for pneumonia-associated hospitalisations. During 2010–2014, there were 141 730 pneumonia-associated hospitalisations across 188 NYC neighbourhoods, of which 43.5% (N = 61 712) were sub-classified as severe. Hot spots of pneumonia-associated hospitalisation spanned 26 neighbourhoods in the Bronx, Manhattan and Staten Island, whereas cold spots were found in lower Manhattan and northeastern Queens. We identified hot spots of severe pneumonia-associated hospitalisation in the northern Bronx and the northern tip of Staten Island. For severe pneumonia-associated hospitalisations, hot-spot patients were of lower mean age and a greater proportion identified as non-Hispanic Black compared with cold spot patients; additionally, hot-spot patients had a longer hospital stay and a greater proportion experienced in-hospital death compared with cold-spot patients. Pneumonia prevention efforts within NYC should consider examining the reasons for higher rates in hot-spot neighbourhoods, and focus interventions towards the Bronx, northern Manhattan and Staten Island.

The process of removal of bacteria from the air of a room of which part only is irradiated with ultra-violet light is discussed.

Formulae are derived for the rate of disappearance of bacteria from the air in such circumstances and for The equilibrium levels reached when bacteria-carrying particles are being continuously introduced into the air at a constant rate. These formulae include terms for the effect of simultaneous ventilation and for the effect of sedimentation of the bacteria-carrying particles.

The results of a short series of tests are compared with those calculated from these formulae and the two found to agree reasonably well on the assumption that the air within both the irradiated and nonirradiated zones is effectively mixed.

Figures are given over a range of humidities for the sensitivity of salivary organisms to ultra-violet irradiation when suspended as small particles in the air.

A chart is presented for the evaluation of the mean radiation intensity within a rectangular volume produced by a point source situated within or on the boundaries of the volume.

Data concerning numerous severe epidemics of poliomyelitis were surveyed for information useful in estimating the size of the immune component of the population by age groups of 1 year. The New York epidemic of 1916 and the Mauritius epidemic of 1945 were chosen as the most suitable for this purpose. It is shown that there was a regularly progressive decline in attack rates for successively older age groups from 2 to 8 years in New York. The attack rate in 8-year-olds was less than 10 % as large as that in 2-year-olds. It is noted that a difference of this magnitude could be accounted for by immunizing infections amounting to 30 % per year for 6 years.

A similar analysis of age specific attack rates during the Mauritius epidemic shows progressive declines of 28, 60, 50 and 53 % for the successive age groups 5–9. An average annual infection rate of 45 % over a 4 year period could account for the ten-fold difference in infection rates between 5-year-olds and 9-year-olds.

An immunizing infection rate of 30 % a year would lead to a pattern of immunity in which the seven youngest age groups had a total susceptible component of 30 % at the beginning of a ‘ poliomyelitis season’. Twenty per cent would remain susceptible at the end of the season when spread of virus terminated.

An annual immunizing infection rate of 45 % would bring about a situation in which 21 % of the five youngest age groups were susceptible at the start of a period of viral prevalence and 12 % at the end. Alternatively, one could consider that on Mauritius there may have been a continuous prevalence of virus in a population in which approximately 15 % of the five youngest age groups were susceptible at any time.

It is suggested that the essentially similar attack rates among children 3–5 years old on Mauritius may have reflected a 3-year period during which homotypic virus was not prevalent, in contrast to its great prevalence during the years prior to that time.

A more detailed discussion and analysis of additional data concerning age-specific attack rates in poliomyelitis will be found in the thesis submitted by Dr Sample to the University of Washington School of Medicine entitled, ‘Some observations on statistical and theoretical epidemiology of infectious diseases, principally poliomyelitis’, in 1955. This is obtainable by Inter-library Loan from the Health Sciences Library, University of Washington, Seattle.

We wish to express our sincere thanks to Dr Blair M. Bennett and Dr William E. Reynolds of the University of Washington for their advice on the statistical and epidemiologic aspects of this study.

Sensitivity, specificity and predictive values of an enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against bovine leukaemia virus (BLV) were evaluated using a representative sample of 145 serum pools, comprising from 3 to 48 individual sera. The sample was constituted according to the frequency distribution of the negative and positive pools analysed during a screening involving the whole cattle population of Belgium. Sensitivity and specificity were estimated to 88·9% and 100% and the predicted negative and positive values were 99·9% and 100%, respectively. These results indicate the use of serum pools is suitable for the detection of BLV infected herds in eradication campaigns.

THE following experiments form part of the general scheme of research undertaken with the object of providing a sound scientific basis for methods of fish preservation and storage.

The bacteriological part of the investigation was first undertaken by the author a year ago and the time has been spent in endeavouring to become acquainted with the peculiarities and characteristics of herring bacteria. There is still a large amount of work to be done in this field before practical experiments on a large scale can be carried out to yield really satisfactory results.