The prominence recently given to the Rous sarcoma has increased the confusion of hypotheses about malignancy. With a view to clarification, one may say that there are three simple hypotheses of outstanding importance, viz.: (1) the living virus hypothesis, which regards living viruses as the actual and effective cause of both the avian and the mammalian disease; (2) the autogenous enzyme hypothesis, which ascribes both diseases to the development within living cells of an ens malignitatis resembling an enzyme rather than a virus; and (3) the “chronic irritation” hypothesis, which explains mammalian malignancy on this principle and considers fowl sarcoma to be of a different nature.

Two phenotypes of human influenza A(H1N1) virus are currently circulating in Japan. One (group 1) agglutinates both chicken and goose red blood cells (CRBC and GRBC), the other (group 2) agglutinates GRBC but not CRBC. In the 1995/6 season, group 2 viruses accounted for 70% of the H1N1 viruses isolated in MDCK cells. The 1995/6 viruses were located on two branches of the genetic tree. One branch contained both group 1 and group 2 viruses and the other branch contained only group 2 viruses. Group 2 viruses had aspartic acid at residue 225 in the haemagglutinin (HA) protein, the key amino acid residue for group 2 phenotype. The HA protein of group 1 viruses had a change from aspartic acid to asparagine at residue 225 and the expressed HA protein of these viruses adsorbed CRBC. Serial passage of group 2 viruses in MDCK cells or embryonated chicken eggs caused these viruses to gain the ability to agglutinate CRBC. MDCK-adapted viruses had the same amino acid sequences of HA polypeptide as the original ones, but egg-adapted viruses had changed amino acid sequences. The expressed HA protein from one egg-adapted virus that originally belonged to group 2 adsorbed CRBC.

The incidence of reported infections of non-typhoid Salmonella is affected by biases inherent to passive laboratory surveillance, whereas analysis of blood sera may provide a less biased alternative to estimate the force of Salmonella transmission in humans. We developed a mathematical model that enabled a back-calculation of the annual seroincidence of Salmonella based on measurements of specific antibodies. The aim of the present study was to determine the seroincidence in two convenience samples from 2012 (Danish blood donors, n = 500, and pregnant women, n = 637) and a community-based sample of healthy individuals from 2006 to 2007 (n = 1780). The lowest antibody levels were measured in the samples from the community cohort and the highest in pregnant women. The annual Salmonella seroincidences were 319 infections/1000 pregnant women [90% credibility interval (CrI) 210–441], 182/1000 in blood donors (90% CrI 85–298) and 77/1000 in the community cohort (90% CrI 45–114). Although the differences between study populations decreased when accounting for different age distributions the estimates depend on the study population. It is important to be aware of this issue and define a certain population under surveillance in order to obtain consistent results in an application of serological measures for public health purposes.

We evaluated the incidence rate of culture-positive central nervous system tuberculosis (CNS TB) in France in 2007 and its time trend between 1990 and 2007. We used a capture–recapture analysis by using data recorded in 2007 by the mandatory notification system and the national network of the National Reference Centre (NRC). The 2007 sensitivity of the NRC was 79·4%. The previous sensitivity for 2000 (75·6%) and that for 2007 yielded a pooled estimate of 77·4% (95% confidence interval 64·8–88·0), which was used to extrapolate the number of culture-positive CNS TB cases from those reported in four surveys (1990, 1995, 2000, 2007). The extrapolated number of culture-positive CNS TB cases fell from 90 to 35 between 1990 and 2007, and the extrapolated incidence rates fell from 1·6 to 0·55 cases/million (P < 0·001). This favourable trend should be closely monitored following the change of the BCG vaccination policy in 2007.

Enteric fever occurs in both temperate and tropical countries, and its spread depends mainly on the sanitary conditions prevailing, on the degree of purity of the drinking water, particularly in the country districts where no general water supplies exist, and on the degree of efficiency of the sewage disposal systems.

1. The incidence of haemolytic streptococci in the patients of a Hospital School for rheumatic children was determined over a period of 1 year.

2. In the total of 1644 throat and 1644 nasal swabs, group A strains were isolated from 20 throat and two nasal swabs. Eighty-seven strains of Lancefield's groups C and G and 54 strains of groups other than A, C, or G were isolated

3. There was no evidence of cross-infection.

4. Factors contributing to the low incidence of group A strains and the absence of cross-infection are discussed.

5. The carriage of groups C and G strains did not appreciably affect the erythrocyte sedimentation rate.

6. Although no direct evidence is available, the experience of the present study suggests that the incidence of streptococci in an institution for rheumatic children may be reduced by: (a) bacteriological screening before admission; (b) regular swabbing and Lancefield's grouping of streptococci isolated for the early detection of group A strains; and (c) administration of penicillin or sulphadiazine prophylactically to even a limited number of children.

We thank Prof. R. S. Illingworth for his advice in the writing of this paper, Dr J. L. Emery for laboratory facilities, Dr R. E. O. Williams for his advice in the planning of the investigation, and the matron and sisters of Ash House Hospital School, Sheffield, for their assistance.

The expenses of the investigation were defrayed by a grant from the Medical Research Council.

Nasal colonization with Staphylococcus aureus occurred in 18% of babies leaving a maternity unit and had risen to 40% by 6 weeks after birth. S. aureus was first acquired by 34·5% of babies after discharge. Female infants were more likely to be colonized than males. Colonization was not significantly different between babies receiving standard postnatal care and those nursed on the Special Care Baby Unit.

Crystal violet (CV) tests showed that purple-reacting isolates accounted for approximately 60% of strains, whether first detected at hospital discharge or subsequently acquired. Purple-reacting strains, once acquired, were significantly better able to persist than non purple-reacting strains and formed a cumulatively higher proportion of the strains isolated at 6 weeks after birth than at hospital discharge. CV purple-reactions were significantly associated with lysis by phages of groups III and I and non-purple-reactions were significantly associated with lysis by phages of group II and/or 94/96.

Maternity units remain a significant route whereby strains of S. aureus with some characteristics associated with a hospital origin gain access to the community.

Experiments I–VIII.

I shows that under the conditions shown the plates were covered with innumerable colonies 7 feet above ground level to ground level. The beds and trestles were used to keep the hut always uniform.

II shows that 8 feet above ground, i.e. on top of the crossbeams, the same conditions obtain.

III, IV, V, and VI show that the same condition exists in the area between the beds or trestles. The beds make no difference, better or worse.

VII shows practically the same condition high up on the beam between the beds. The inverted plates naturally show less colonies, as the organisms mostly fall on to the plates.

VIII confirms the above.

There is only one conclusion to draw from these experiments, and that is that practically speaking there is no difference in the number of organisms on the ground floor and 8 feet above it, in the ordinary men’s sleeping huts, Barrack Design 230/14.

(1) A number of Dysentery bacilli of the mannite-fermenting type have been isolated from an English asylum.

(2) These bacilli may be divided into two sub-groups, (a) those that do, and (b) those that do not (1) ferment sorbite and (2) form indol in peptone beef broth in six days.

(3) Several attempts to infect a monkey with sorbite-fermenting strains were not successful.

(4) No Dysentery bacilli were found in an examination of a considerable number of flies infesting the surroundings of chronic and acute cases of bacillary dysentery.

My thanks are due to Dr H. de R. Morgan for kindly co-operation in part of this work, to Dr J. C. G. Ledingham for his valuable advice and assistance at all times, and to Dr W. F. Menzies for supplying the material for examination.

1. The appearance and disappearance of typhoid bacilli in the faeces in these four cases bore no relation to changes in the diet nor to the physical state of the stools, but the later they appeared the shorter was the duration of their appearance.

On the disappearance of typhoid bacilli from the stools the intestinal flora tended to become more simple.

2. B. coli was the only organism invariably present at every examination.

3. Streptococci were very much more abundant in the earlier stages of the disease, when milk formed the greater part of the diet, than in the later stages.

4. In two cases where boils occurred on the body the causative organism had previously been isolated in large numbers from the faeces.

5. With stools slightly alkaline to litmus the flora in these cases was relatively simple and fermentative in type. There is no apparent advantage, therefore, in giving a high carbohydrate diet except in cases of marked alkalinity and putrefaction.

The titres of the complement-fixation test and the agglutination test run parallel in rabbit sera, but not in human sera. These facts are explained in connexion with the specificity of complement.

1. The abscesses in the viscera, especially the spleen, and in the peripheral lymphatic glands, some of which contain living plague bacilli, which have been previously described as “chronic plague in rats” are shown to be plague lesions in the process of healing. The name “resolving plague” is more appropriate.

2. These lesions are found most frequently towards the close of, and immediately after, the acute plague epidemic.

3. They have been found frequently in rats in Belgaum and Poona, and a re-examination of Bombay rats shows that they also occur there. We had previously only found them in the Punjab villages.

Mice given an intraperitoneal injection of 0.5 mg. Corynebacterium parvum (dry weight) before vaccination with heat-killed (HK) or acetone-killed (AK) Salmonella typhimurium vaccine and later challenged intraperitoneally with S. typhimurium strain 1566, showed a statistically significant increase in mortality when compared with mice that had received only C. parvum but no vaccine. They also showed a higher mortality rate than mice receiving only HK or AK vaccine or mice that had received no vaccine before challenge. Prior administration of C. parvum to mice that are vaccinated with HK or AK vaccine appears to make them more susceptible to an intraperitoneal challenge with S. typhimurium. This was more apparent with HK vaccine than with AK vaccine.

The following contribution to the aetiology of cerebrospinal meningitis is published with a view to calling attention to the possible part played by dust in the causation of this disease. The strong connection between dusty occupations and cases of cerebrospinal fever, as here detailed afford, it is believed, a prima facie presumption that dust may be one of the vehicles of the specific germ.

Good fixation of complement was obtained with the infective virus fraction of the Mahoney Type 1 poliomyelitis virus which had been adapted to suckling mice. The presence of a soluble antigen, specific to Type 1 virus, was also demonstrated but was small in amount.

The infective virus fraction of the suckling mouse adapted MEF1 Type 2 poliomyelitis virus produced as good fixation of complement as did Type 1, but the fixation of complement by the MEF1 soluble antigen was far greater than that obtained with the Mahoney strain.

The author would like to thank Prof. A. Kipps for his interest and encouragement and Miss M. Butchart for her valuable technical assistance. She is also indebted to Dr H. Malherbe of the Poliomyelitis Research Foundation, Johannesburg, for the Type 1 monkey immune serum.

We investigated whether there are differences between the natural history of B and C chronic hepatitis in a southern Italian population, and whether the chronic viral hepatitis population was modified by the introduction of the anti-HCV test in 1989. We examined clinical charts of 1120 patients consecutively admitted to our division from January 1979 to December 1998 with the histological diagnosis of chronic viral hepatitis (304 from 1979 to 1988; 816 from 1989 to 1998). We found significant differences only in age at diagnosis (higher in the second decade, P=0·001), and in aetiology (HBV decreased in the second decade, P<0·0001). We were able to follow up 449 patients for 2–20 years (311 with HCV and 138 with HBV infection), and found that chronic HCV evolved to cirrhosis more frequently than did chronic HBV; but in both types time to development of cirrhosis and the incidence of death were similar. Our data confirm that a higher onset age of HBV and of HCV is frequently observed in those subjects who have a faster disease progression.

Nine isolates from pigs persistently infected with a recent Italian isolate of swine vesicular disease (SVD) virus, ITL/9/93, were collected sequentially over 121 days and were characterized antigenically and biochemically. There was an accumulation of amino acid (aa) substitutions in the capsid proteins throughout the carrier state that could be correlated with alterations in antigenicity in virus isolates collected late stage in infection. The aa substitutions detected mainly occurred in VP1 and antigenic changes were detected in late isolates both at antigenic site 1, resulting in loss of binding of Mab 4GO7, and at a closely located site which has not yet been named, recognized by Mab C29. In further experiments groups of pigs were exposed to a range of SVD viruses, but no virus was isolated beyond 16 days post infection (dpi) nor viral RNA detected beyond 42 dpi. Attempts to transfer infection to sentinel pigs introduced some time after initial infection of the original pigs were largely unsuccessful. The carrier state was established in only one out of five experimental infections of pigs with SVD virus and can therefore be considered a rare sequel to infection with SVD virus and is of limited significance in the epidemiology of the disease.