Intradermal inoculation of the tongue, subcutaneous, intracutaneous and intra-venous inoculation were compared in determining the relative facility with which foot-and-mouth disease infection can be produced in cattle.

In seven experiments using six virus strains, least virus was required to infect by the intradermal tongue route, but wide variation was observed between the amount of virus required to infect by this route and by the subcutaneous, intracutaneous or intravenous routes. The smallest difference between tongue and subcutaneous inoculation was not significant, and the largest difference was that 250,000 times more virus was required to infect by the subcutaneous route. The readiness with which infection is produced by routes other than intradermal inoculation of the tongue may be greatly influenced by the strain of virus used.

Intranasal instillation of the virus was also compared with intradermal tongue inoculation. As with subcutaneous inoculation, more virus was required for infection by the intranasal route and, similarly, the results suggest that considerable variation would be found in the amount of different strains required.

A correlation is suggested between this variation and the variation observed in the ‘invasiveness’ of strains in cattle exposed to contact infection.

Attention is drawn to the significance of the observations recorded in this paper in relation to tests of foot-and-mouth disease vaccines for non-infectivity.

Viruses from the recent epidemic of swine vesicular disease (SVD) in Europe have been isolated and characterized by antigenic and genetic methods to examine the likely epidemiological origins of the disease. Antigenic analysis was performed on 77 SVD viruses (SVDV) isolated in Europe between 1966 and 1994 using two panels of monoclonal antibodies (MAb) in a trapping ELISA. Genetic analysis of 33 of the SVD viruses by reverse transcription-polymerase chain-reaction (RT-PCR) amplification and nucleotide sequencing of the 1D (VP1) coding region was also performed. Comparison of the nucleotide sequences with each other and with three other previously published SVDV sequences revealed four distinct groups which correlated exactly with the results of the pattern of reactivity with MAbs. The first group consisted solely of the earliest SVD virus isolated (ITL/1/66) while the second group comprised viruses present in Europe and Japan between 1972 and 1981. The third group consisted of viruses isolated from outbreaks of SVD in Italy between December 1988 and June 1992. Viruses isolated between 1987 and 1994 from Romania, the Netherlands, Italy and Spain formed a fourth group. The genetic and antigenic similarity of the most recent virus isolates from Western Europe to a virus isolated in Romania 5 years previously suggests that the possible origin of the recent epidemic of swine vesicular disease in Western Europe was in Eastern Europe.

The aim of the European Sero-Epidemiology Network is to establish comparability of the serological surveillance of vaccine-preventable diseases in Europe. The designated reference laboratory (RL) for measles, mumps, rubella (MMR) prepared and tested a panel of 151 sera by the reference enzyme immunoassay (rEIA). Laboratories in 21 countries tested the panel for antibodies against MMR using their usual assay (a total of 16 different EIAs) and the results were plotted against the reference results in order to obtain equations for the standardization of national serum surveys. The RL also tested the panel by the plaque neutralization test (PNT). Large differences in qualitative results were found compared to the RL. Well-fitting standardization equations with R2⩾0·8 were obtained for almost all laboratories through regression of the quantitative results against those of the RL. When compared to PNT, the rEIA had a sensitivity of 95·3%, 92·8% and 100% and a specificity of 100%, 87·1% and 92·8% for measles, mumps and rubella, respectively. The need for standardization was highlighted by substantial inter-country differences. Standardization was successful and the selected standardization equations allowed the conversion of local serological results into common units and enabled direct comparison of seroprevalence data of the participating countries.

Listeriosis is a rare but severe foodborne disease with low morbidity and high case-fatality rates. Pregnant women, unborn and newborn babies are among the high-risk groups for listeriosis. We examined listeriosis cases reported to the enhanced surveillance system in England and Wales from 1990 to 2010 to identify risk factors influencing outcome. Cases were defined as pregnancy-associated if Listeria monocytogenes was isolated from a pregnant woman or newborn infants aged <28 days. Of the 3088 cases reported, pregnancy-associated listeriosis accounted for 462 (15%) cases and 315 cases resulted in a live birth. Several factors were identified as affecting the severity and outcome of listeriosis in pregnancy in both mother and child including: presence or absence of maternal symptoms, gestational age at onset of symptoms, and clinical presentation in the infant (meningitis or septicaemia). Deprivation, ethnicity and molecular serotype had no effect on outcome.

Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, showed the appearance of the O4[ratio ]K68 serovar for the first time in March 1998 alongside the continued predominant incidence of the O3[ratio ]K6 serovar. Strains belonging to both these serovars have been reported to possess pandemic potential. The genomes of O3[ratio ]K6 and O4[ratio ]K68 strains and for comparison, non-O3[ratio ]K6 and non-O4[ratio ]K68 strains isolated from two different countries, India and Thailand, were examined by different molecular techniques to determine their relatedness. The O3[ratio ]K6 and O4[ratio ]K68 strains from Calcutta and Bangkok carried the tdh gene but not the trh gene. Characterization of representative strains of these two serovars by ribotyping and by arbitrarily primed-polymerase chain reaction (AP-PCR) showed that the isolates had identical ribotype and DNA fingerprint. Pulsed-field gel electrophoresis (PFGE) performed with the same set of strains yielded nearly similar restriction fragment length polymorphism (RFLP) patterns for the O3[ratio ]K6 and O4[ratio ]K68 isolates from Calcutta and Thailand. Phylogenetic analysis of the NotI RFLP showed that the O3[ratio ]K6 and O4[ratio ]K68 strains formed a cluster with 78–91% similarity thus indicating close genetic relationship between the two different serovars isolated during the same time-frame but from widely separated geographical regions. The non-O3[ratio ]K6 and non-O4[ratio ]K68, in contrast, showed different ribotype, AP-PCR and PFGE patterns.

1. Group variants devoid of type antigen, described in the previous section, provide material for ascertaining the various components of the antigen in the mannitol-fermenting dysentery bacilli.

2. Flexner Y, as defined by Andrewes and Inman, is not a valid type. The strains which are regarded as being of this type, such as Y Hiss and Russell and Y Lentz, are old strains which have lost their type antigen and possess only group antigen. The reason why many newly isolated strains are identified as Y is because the antiserums used for their recognition contain more group than type agglutinin.

3. The four Flexner types V, W, X, and Z, each possess a distinctive type antigen and share a complex group antigen. They do not, as suggested by Andrewes and Inman, possess minor quantities of each other's type antigen.

4. 103, P 119, and the 88-Newcastle-Manchester series have also distinctive type antigens, and share the same group antigen with V, W, X, and Z.

5. It is considered that the existing Flexner group should be extended to include all organisms which have a type-specific antigen and share this common group antigen. The three types in (4) should therefore be placed in the group and named accordingly.

6. Six types which have the biochemical reactions of the Flexner group, and which have individual type antigens but no Flexner group antigen, are provisionally placed in a separate loose group.

We examined the incidence rate and prognosis of tuberculosis in a cohort of patients with liver cirrhosis in Denmark. In a study cohort of 22675 patients with liver cirrhosis, we identified 151 cases of tuberculosis from 1977 to 1993. The incidence rate was 168·6 per 100000 person-years of risk, and the highest incidence rate was among men above 65 years of age, with an incidence rate of 246·0 per 100000 person-years of risk. The 30-day case-fatality rate was 27·3% and the 1-year case fatality rate was 47·7%. The results demonstrate that patients with liver cirrhosis are at increased risk of tuberculosis. Additionally, it is suggested that liver cirrhosis is an independent risk factor for tuberculosis, and that patients with liver cirrhosis who acquire tuberculosis have a poor prognosis.

A review is given of some of the literature concerned with bacterial infections and immunity in invertebrates and cold-blooded vertebrates. Among the former, insects have been most fully studied, although a certain amount is known of the immunological reactions of marine invertebrates. Diseases of insects are mainly generalized, bacteraemic conditions, and the great majority are caused by Gramnegative cocco-bacilli. Diseases of cold-blooded vertebrates also are usually generalized, but bacteria from a very wide variety of groups have been isolated from them.

It is probable that this resemblance in the infections of these widely separated groups of animals is due to the fact that, unlike mammals and birds, with whose reactions we are more familiar, the regulation of their temperature and the constitution of their body fluids is not exact. This toleration of wide variations of their own physical and chemical constitution must reduce their sensitivity to the changes produced by infection, and hence decrease the likelihood of a local reaction, designed to confine the invading organism to the immediate region of its point of entry, i.e. a local inflammation.

The production of humoral antibodies appears to be almost universal in the animal kingdom, although greatly affected by changes in temperature.

The effect of temperature upon the balance between host and parasite is also discussed. This question bears upon the problem of occasional pathogenesis by saprophytes. Even among mammalian pathogens the borderline between parasite and saprophyte is an indistinct one, especially in such cases as Proteus and Pseudomonas pyocyanea, and even those species which are usually regarded as exclusively parasitic may readily be constrained to adopt a saprophytic existence on artificial culture. Where cold-blooded animals are concerned the boundary is even more difficult to draw, and it is possible that under suitable conditions, bacteria which are normally saprophytes may be capable of causing infection. This point will be impossible of proof until more sensitive means of definition of bacterial species are discovered.

The analysis of a series of haemolytic streptococci of scarlatinal origin by agglutinin absorption experiments has revealed the existence of three chief types. Among 81 strains from scarlatinal throats 37 have been shown to belong to one or other of the three types; 12 have been classified as Type 1, 14 as Type 2 and 11 as Type 3. In addition, two strains have been found which absorbed the agglutinin from both Types 1 and 3 sera.

Weekly (August 2003–December 2008) numbers of five common paediatric diseases and the incidence of respiratory viruses were obtained from a children's hospital in Singapore and correlated with climate data using multivariate time-series techniques. Upper respiratory tract infections were positively correlated with the incidences of influenza A, B, respiratory syncytial virus (RSV) and parainfluenza viruses (types 1–3 combined). Lower respiratory tract infections were positively correlated with only the incidence of RSV. Both upper and lower respiratory tract infections were negatively correlated with relative humidity. Asthma admissions were negatively correlated with maximum temperature and positively correlated with the incidence of influenza B and increasing hours of sunshine. Although sporadic cases of adenovirus infection were identified, not enough cases were available for a more detailed analysis. Gastroenteritis and urinary tract infections, included as control diseases, were not correlated significantly with any climate parameters. These correlations are compatible with current understanding of respiratory virus survival under certain climate conditions and may assist the prediction of disease burdens and hospital resource planning in such tropical environments.

To estimate the incidence of Lyme borreliosis in France, describe its clinical presentations, and assess its potential risk factors, we conducted a nationwide prospective study in the French Sentinelles Network, consisting of 1178 general practitioners (GPs). Of these, 875 (74%), i.e. 1·6% of all French GPs, participated in the study from May 1999 to April 2000. Eighty-six cases of Lyme disease were reported and validated, of which 77 (90%) consisted of erythema migrans. At national level, the incidence was estimated at 9·4/100000 inhabitants. Compared to the French general population, Lyme disease patients were older (P<10−4), more were living in rural areas (P<10−3), and amongst the working population, more were farmers (P<10−3) and fewer, salaried workers (P<0·005). Cervidae density correlated strongly with the estimated regional incidence of Lyme disease (r=0·82). Both incidence data and identified risk factors can help to target measures for its prevention and treatment.

Suspensions of FMD virus treated with 0·05% formalin at 26° C. for periods up to 144 hr. remained infective for cattle, although the infectivity could not be detected in the presence of aluminium hydroxide. Infectivity was detected in similar virus suspensions which had been treated with 0·05% AEI at 37° C. for 8 hr. but not in suspensions treated for 12 hr.

Vaccines prepared from these suspensions were antigenically potent and serum neutralization tests demonstrated the development and regression of serum antibody. The AEI vaccines were at least as potent as the corresponding formalin vaccines.

Ribotyping with the restriction enzyme XbaI was used to study the dynamics of carriage of non-encapsulated Haemophilus influenzae (NCHi) in Aboriginal infants at risk of otitis media. Carriage rates of NCHi in the infants in the community were very high; the median age for detection was 50 days and colonization was virtually 100% by 120 days of age and persisted at a high level throughout the first year of life [1]. Eighteen different ribotypes of NCHi were identified from 34 positive swabs taken from 3 infants over a period of 9 months. The same ribotypes were recovered for up to 3 months from consecutive swabs of individual infants, and 12 of 27 swabs (44·4%) yielded two ribotypes from four colonies typed. Statistical analysis suggested that most swabs would have been positive for two ribotypes if enough colonies had been typed although the second most frequent ribotype was detected on average in only 13% of strains. Early colonization and carriage of multiple ribotypes of NCHi may help to explain the chronicity of carriage and thus the persistence of otitis media in Aboriginal infants.

A cross-sectional telephone survey was conducted in Denmark throughout 2009 to determine the incidence of acute gastrointestinal illness (AGI). Using the Danish population register, a random population sample stratified by gender and age groups was selected and mobile or landline phone numbers found. Representative numbers of interviews were performed by gender, age group and month. A recently proposed international case definition of AGI, including cases with diarrhoea and/or vomiting in a 4-week recall period, was used. A total of 1853 individuals were included and 206 (11·1%) fulfilled the case definition; 78% reported diarrhoea. This corresponds to an overall standardized incidence rate of 1·4 (95% CI 1·2–1·6) episodes of AGI per person-year. The incidence rate was generally higher in the younger age groups; only being 2·3, 1·9 and 0·80 per person-year in the 0–9, 10–39 and ⩾40 years age groups, respectively. The incidence rate estimates were considerably higher when calculated from shorter recall periods.

Pigs were infected by the intranasal instillation of a large dose (ca. 107·0 ID 50) of a highly virulent strain of African swine fever virus (ASFV) and the progress of the infection was studied by the ‘routine titration approach’ (Mims, 1964) using pig bone marrow cultures.

Virus growth was established within 16–24 hr. in the retropharyngeal but not in the alimentary or nasal mucosae or the tonsils. By 24–40 hr. the virus was consistently present in the retropharyngeal lymph nodes, almost invariably the medials; titres in these nodes exceeded those in the associated mucosa by 48–72 hr. Generalization, presumed to have occurred via the tracheal lymph ducts and the blood stream, was generally demonstrable after 72 hr., i.e. by the time of the onset of pyrexia or 24 hr. prior to this.

On average 11% of the total infectivity in the blood was present in the plasma, with the rest assumed to be cell-associated. A mean of about 45% of the total infectivity was recovered in erythrocyte fractions in which the concentration of leucocytes had been materially reduced; fractions with increased leucocyte counts contained relatively little virus and it was concluded that the great majority of circulating virus was closely associated with the erythrocytes. Adsorption of ASFV to normal pig erythrocytes was demonstrated in vitro.

The greatest concentrations of virus were recorded in the lymph nodes, especially those of the cephalic region, and in the spleen, where titres commonly attained 108·0 to 109·0 HAD 50/g. and exceeded those in the blood. They were, therefore, thought to be the source of much circulating virus, although there was some evidence that the liver, lungs and bone marrow may also have contributed, at least in some animals. There was no evidence that the mucosae of the alimentary and respiratory tracts or the kidney, myocardium and brain were a source of significant amounts of virus. The virus demonstrable in Peyer's patches did not exceed that in the intervening ileal mucosa.

Although contact transmission of ASF does not normally occur during the first 12–24 hr. of fever, considerable amounts of virus were usually present in the nasal and intestinal mucosae at 72 hr. It was probable that this infectivity was due to the blood content and that excretion did not occur until the epithelium was breached.

Three pigs, all of which had lesions of a portal cirrhosis, showed a delayed or restricted generalization of virus, in comparison with the other twenty-eight animals which behaved according to a regular pattern.

We are grateful to Mrs M. O'Sullivan and Mrs E. Douglas for painstaking technical assistance and to Mr C. S. Rampton, A.I.M.L.T., for the preparation of the figures.

Campylobacter jejuni was an almost regular finding in chickens and in minced meat from pigs and cattle sold in ordinary food stores. The bacteria survived on the food at 4 °C for one week and frozen at – 20 °C for three months. None of the stains tested survived heat treatment at 60 °C for longer than 15 min. C. jejuni is apparently a frequent guest in most kitchens. Correct food handling and heat treatment to at least 60 °C for 15 min should be enough to prevent infection.

Sequencing of part of the 1D gene of foot-and-mouth disease virus was used to determine the relationships between SAT-2 viruses isolated from outbreaks which occurred in cattle in Zimbabwe and Namibia and in impala in South Africa between 1979 and 1989. The results demonstrated that the outbreaks in different countries were unrelated. Surprisingly close relationships were shown between all SAT-2 viruses isolated from cattle in Zimbabwe since 1983 but the two major epizootics which occurred in 1989 were caused by viruses which were clearly different. Conversely, two apparently unrelated outbreaks in impala in South Africa were caused by viruses which could not be distinguished.

The death certificates for cancer of the lung and of the larynx in males from England and Wales for the years 1921–32 inclusive, numbering 18,280, have been investigated.

Sources of error in statistical work on death certificates are discussed.

Latterly autopsies have been made upon about 28 per cent, of cases of cancer of the lung, and 9 per cent, of cases of cancer of the larynx. The increase in the recorded cases of lung cancer is not nearly accounted for by the increase of data obtained by autopsy.

The agricultural and coal-mining industries show a low incidence of cancer of the lung and of the larynx.

The factors which lead to silicosis appear not to be very active in producing cancer of the lung or larynx, but in metal grinders the incidence of cancer of the lung is 2¼ times that in the general population. A group of open-air occupations, where there is exposure to the dust of roads, have rather high ratios for cancer of the lung and of the larynx with the exception that motor drivers have a normal liability to cancer of the larynx. On the whole, no occupation involving exposure to any kind of dust has been found in which there is any very high incidence of cancer of the lung or larynx. Cases of cancer of the lung in asbestos workers are described in recent literature, but none has been found among the certificates considered here (up to 1932).

Workers exposed to coal gas and tar, and those engaged in the preparation and sale of tobacco, tend to show an increased prevalence of cancer of the lung.

Occupations concerned with the supply of alcohol have a high incidence of cancer of the larynx.

To investigate the occupational incidence of cancer thoroughly one should have before one, simultaneously, comparable figures for cancer of all parts of the body which could be effected by an external agent.

With regard to the view, that the recent rapid increase in recorded deaths from cancer of the lung is due to the detection of more cases by improved diagnosis, the very moderate ratio (129) for cancer of the lung in medical men is noteworthy, for this is an occupation where the availability of the existing methods for the detection of cancer is presumably at a maximum.

Data are given of the prevalence of cancer of the lung and larynx in men and in women, and of the rate of increase in the two sexes in recent years. The greater incidence of cancer of the lung upon men than upon women is discussed. The recent rate of increase of cancer of the lung in men is found to be not much greater than that in women, when these increases are reckoned in percentages.

The increase in recorded cases of cancer of the lung may be due to (1) an actual increase; (2) improvement in diagnosis; (3) fashion in diagnosis; or to any combination of these factors. A comparison is made between the increase of cancer of the lung, and of cancer of the prostate; the number of deaths attributed to cancer of the prostate appears to have reached a steady level.

No special occupations have been found to which the increase in the total of cases of cancer of the lung can be attributed; rural workers show an increase which is not much less than that in the general population.

No evidence has been found that tarring of roads has affected the incidence of cancer of the lung upon the general population. Such data as are available suggest that coal tar in the atmosphere, whether derived from roads, domestic chimneys, or any other source, does not readily give rise to cancer of the lung. Cotton-mule spinners show an especially small liability to cancer of the lung although they inhale air sprayed with an oil which produces cancer of the skin.

Improvements in diagnosis must have led to the detection of a larger proportion of the existing cases of cancer of the lung; whether there has been an actual increase in these cases cannot be decided from the data presented here, but a source of evidence on this question is suggested.

We are indebted to the Registrar-General for the data considered in this paper, and also for kindly permitting us to use some figures which have not yet been officially made public. We have received much assistance in the classification of occupations from some members of the Staff of the General Register Office, to whom we wish to express our gratitude. We wish to thank also Dr J. C. Bridge, Senior Medical Inspector of Factories, for information upon various matters, and especially upon silicosis. We are greatly indebted to Miss L. D. Henderson for much assistance in carrying out the calculations.

A form of ultramicroscope apparatus is described which enables the evaporation of mist droplets to be followed for long periods. A rough method of estimating the size distribution in aerosols is also given.

The rates of evaporation of particles of various phenol solutions have been studied, the solutions chosen being of possible interest as aerial germicides. It is shown that the typical evaporation curve for a binary mixture consists of three parts, which in actual cases need not all be present. Sometimes the more detailed history of an evaporation can be deduced from the results.

The approximate effective size distributions in mists of hexyl-resorcinol—propylene-glycol solutions have been measured and compared with the evaporation rates.

It is shown that the efficiency of aerial germicides is partly a function of their volatility, and three rough classes are distinguished. But biological evidence is adduced which suggests that the solubility of the germicides in water may be of equal importance, and that the liquid in which the germicide is dissolved is not without effect.

A centrifuge is described which enables the maximum particle size in a mist to be limited to a desired value.

Methods of estimating quantitatively germicidal aerosols are discussed, and a method described which has been found to give reasonably accurate results in practice. Tentative experiments have been made to determine whether the materials studied are likely to cause corrosion of metals, etc., after pro-longed use.

The collision theory of aerial disinfection is discussed, as is also the applicability of Langmuir's treatment of the evaporation of fine particles in mixtures.

The development of the experimental technique involved in the biological investigations appertaining to air disinfection has been discussed, together with the numerous fallacies arising and the means by which these have been overcome.

The construction of a special pair of experimental chambers is described, and details given, both as regards the bacteria and germicides, of the exact experimental conditions under which the most consistent results can be obtained.

The requisite characteristics of germicidal mixtures which could be utilized for air disinfection are considered, and examples of suitable germicides and solvents are given. The method of recording and evaluating the results of a varied assortment of experiments is explained to facilitate inter se comparison.

Examples are given of the lethal effectiveness in the air of several germicides in broth emulsions, both with and without the presence of serum, on stock cultures of selected types of bacteria. The sensitivity to the germicides of the bacteria making up the flora of the average normal saliva is compared with that of broth emulsions of bacteria.

10% hexyl-resorcinol dissolved in propylene-glycol+0·05 % sulphonated lorol (“S2”) was the most effective all round germicidal mixture of those tested. Various other germicides were found equal in germicidal activity in the air, but for reasons stated have been deemed unsuited for use in the presence of man.

The relationship between germicidal efficiency in the air and mist particle size and persistence has been studied by means of centrifuged mists. Particles of 0·5–1·0μ radius are shown to be the most useful in dealing with bacterial particles containing organic matter. Laboratory cultures, emulsified in broth, have been sterilized in mist dispersions by droplets of bactericides at least as small as 0·25μ radius.

Tests on the penetrating abilities of bactericidal mists and bacteria through certain cloths have been performed.

Experiments to demonstrate the surface sterilizing properties of aerosols have been performed, and examples of differences in effect on horizontal and vertical surfaces are noted.

The degree of tolerance of man and animals (mice) for a number of phenolic substances and some organic solvents has been compared with the degree of tolerance of bacteria for the same substances.

The tests on man have been confined to the detection by the special senses of the substances suspended in the air as a fine mist.

The tests on animals were designed to show acute and chronic effects, the results being recorded in terms of clinical symptoms and pathological changes in the organs. A record was also kept of the findings as regards protozoal parasites of the host, and compared with the normal incidence among ordinary laboratory stock.

Tests on bacteria were instituted for the purpose of gaining information on the host-parasite tolerance ratio for our germicides when in the air and when in the test-tube.

A study of the growth phases of pleuropneumoma has been carried out by two new methods: (1) a new fixing and staining technique, (2) a new dark-ground method. The results obtained by the two methods are in good agreement, and the life cycle of the organism of bovine pleuropneumoma and related microbes as revealed by means of both methods has been described.