Heterogeneity in the number of secondary tuberculosis (TB) cases per source case, the effective reproductive number, R, is important in modelling prevention strategies' impact on incidence.

We estimated mean R (Rm) and calculate the dispersion parameter of this distribution, k, using surveillance and genotyping data for U.S. cases during 2009–2018. We modelled transmission assuming cases in a cluster have matching genotypes and share characteristics related to geography, temporal proximity (i.e. serial interval) and time since U.S. arrival among non-U.S.-born persons.

Complete data were available for 55 330/85 958 cases. Varying the serial interval and geographic proximity used to derive clusters, we consistently estimated Rm<1.0 and k < 0.08; the low value of k indicates a small number of source cases produce a disproportionate number of secondary cases.

U.S. TB reproductive number has a highly skewed distribution, indicating a minority of source cases disproportionately contribute to transmission.

This study aimed to investigate differences in the antimicrobial susceptibility of members of the Mycobacterium abscessus complex (MABC): subsp. massiliense and subsp. abscessus, and to identify associations between strain genotypes and antimicrobial resistance phenotypes. A total of 383 clinical MABC isolates (subsp. abscessus: n = 218, 56.9%; subsp. massiliense: n = 163, 42.6%; subsp. bolletii: n = 2, 0.5%) were characterised using multilocus variable number tandem repeat (VNTR) typing and drug susceptibility testing. Most isolates exhibited susceptibility to amikacin, clarithromycin and azithromycin but resistance to cefoxitin and minocycline was statistically more associated with isolates unclustered by VNTR type. The Simpson's diversity indexes of VNTR typing for M. abscessus and M. massiliense isolates were 0.999 and 0.997, respectively. Genotyping of M. abscessus and M. massiliense isolates by VNTR may provide valuable information for predicting resistance phenotype.

A considerable degree of uniformity of results of the Wassermann test has been found among five pathologists.

Certain differences (chiefly in the case of weakly positive sera) have, however, been noted. Their main source lies in the use of different methods and not in any lack of personal ability or care on the part of the worker.

It is believed that the number of these could be greatly reduced by adopting a uniform method of performing the test and by standardising the details of the method.

The supply of a standard antigen and haemolysin to pathologists is recommended.

To assess the relative importance of ulcerative and non-ulcerative sexually transmitted disease in the transmission of HIV, a seroprevalence study was conducted on 2210 patients at the sexually transmitted diseases (STD) clinic of the S. Maria e S. Gallicano Hospital in Rome, between 1989 and 1994. Among male patients, by univariate analysis, strong predictors of HIV infection were homosexuality, sexual exposure to a HIV-positive partner, hepatitis B virus infection, and positive syphilis serology. An increased risk was estimated for patients with past genital herpes (odds ratio (OR) 3·86, 95% confidence intervals (CI) 0·40–18·2), and primary syphilis (OR 5·79, 95% CI 0·59–28·6). By multivariate analysis, a positive association was found with homosexuality (OR 6·9, 95% CI 2·9–16·5), and positive syphilis serology (OR 3·5, 95% CI 1·3–9·2). An adjusted OR of 2·41 was calculated for current and/or past genital herpes. These results, although not conclusive, suggest a role of ulcerative diseases as risk factors for prevalent HIV infection, and indicate that positive syphilis serology is an unbiased criterion for identifying individuals at increased risk of HIV infection.

Radioimmunoassay (RIA) for rubella-specific IgM antibodies was compared with haemagglutination-inhibition (HI) in conjunction with gel filtration for the diagnosis of rubella infection in pregnant women during a 1-year period. In total 476 women were investigated of whom 221 were tested for rubella IgM. Both techniques gave positive results with 64 sera, and RIA alone with one additional serum.

Difficulties associated with the removal of non-specific HI activity were encountered with four sera all of which were negative by RIA.

RIA was found to have practical advantages over the gel filtration method but is at present technically more difficult to perform.

A study has been made of the epidemic and endemic aspects of infective hepatitis as it affects the civilian population of Palestine. Since the data analysed pertain primarily to Jews who have migrated to the country during the last 25 years, the results must be interpreted in terms of this group, although available data for other segments of the population are presented. The analysis was based on (a) records of persons who were members of the Sick Fund of the General Federation of Jewish Labour (W.S.F.) and the Rural Sick Benefit Fund (R.S.B.F.), (b) records of infants and children under the supervision of the Hadassah Medical Organization (H.M.O.) and the Tel-Aviv municipality, (c) records of persons admitted to H.M.O. hospitals over a 20-year period, and (d) records of the Government Department of Statistics for 1944.

Sick-fund records and those of supervised children afford reasonably reliable incidence rates for these groups in various parts of the country. Hospital records, however, which have been the only source of information regarding other aspects of the disease are affected to an unknown extent by various factors which determine the selection of persons who apply for hospital care. The analysis has brought out the following points:

1. Incidence of infective hepatitis has been estimated at 100 per 10,000 of the people of Palestine. About 2 per 10,000 Jews in the population were hospitalized with the disease. Incidence was significantly greater in rural districts.

2. Incidence rose to epidemic proportions during the years 1941–4 in the various administrative subdistricts inhabited largely by Jews. On the coastal plain the epidemic reached its peak in 1942, but in the interior incidence was highest in 1943. Rates declined in 1944.

3. Fatality was generally low, but the disease may pursue a severe and even fatal course among children and pregnant women.

4. The monthly distribution of hepatitis cases varied somewhat with age and district. In general monthly indices reached their peak in December and January and dropped to a minimum in May, but among young children a subsidiary peak appeared in July and August.

5. Among native Palestinians 50% of the hospitalized patients were under 5 years of age, whereas among those born elsewhere, whether in Europe, the Mediterranean basin or the Near East, some 60% were between 15 and 29 years of age.

6. Males and females born in Palestine were equally affected, but there were more immigrant males than females in the hospitalized group of cases. Unmarried persons evidently acquired the disease sooner after their arrival than did those that were married.

In conclusion it may be said that the information derived from the hospital records suggests that the disease is endemic in Palestine and is usually acquired in childhood. Immigrants from non-endemic regions are likely to become infected soon after their arrival. The monthly distribution of infective hepatitis cases resembles that of the respiratory diseases, but the secondary rise among children in July and August suggests that flies and food contamination may play a part in transmission.

By careful investigation of the somatic antigens of the true cholera vibrios —the strains containing O factor I according to Gardner's grouping (1935)— it was found, as did Scholtens (1933), that the cholera vibrios may be divided into two serological groups: one containing the antigenic factor A and the other the antigenic factors AB.

This finding may be of importance in epidemiological investigations and in the preparation of vaccines.

Escherichia albertii is an emerging foodborne enteropathogen associated with infectious diarrhoea in humans. In February 2023, an outbreak of acute gastroenteric cases was reported in a junior high school located in Hangzhou, Zhejiang province, China. Twenty-two investigated patients presented diarrhoea (22/22, 100%), abdominal pain (21/22, 95.5%), nausea (6/22, 27.3%), and vomiting (3/22, 13.6%). E. albertii strains were successfully isolated from anal swabs collected from six patients. Each isolate was classified as sequence type ST2686, harboured eae-β gene, and carried both cdtB-I and cdtB-II subtypes, being serotyped as EAOg32:EAHg4 serotype. A comprehensive whole-genome phylogenetic analysis revealed that the six isolates formed a distinct cluster, separate from other strains. These isolates exhibited minimal genetic variation, differing from one another by 0 to 1 single nucleotide polymorphism, suggesting a common origin from a single clone. To the best of our knowledge, this represented the first reported outbreak of gastroenteritis attributed to E. albertii outside of Japan on a global scale.

The experiments now described were carried out in Lagos and Khartoum, and although the hoped-for end-result, the production of a sheep strain of neurovaccinia, was not realized, certain points of interest have arisen and are recorded in the hope that they may be of help to other workers concerned with vaccinia vaccine production.

The subjection of the scrotum of the dog for 10 minutes daily for 28 days to a stream of water at 39·5 40·0° C. does not materially affect the testes. It is unlikely that ordinary hot bathing affects male fecundity.

The Harbour of Poole lies a few miles to the West of Bournemouth. It has an area approximately of 10,000 acres, but there is only a very narrow passage between its waters and the open sea. The width of this bottle-neck entrance is about 250 yards. The last published Admiralty chart gives the rate of the incoming tide through this narrow entrance at 3¼ knots, and of the outgoing tide at 4 knots. The local opinion is that these official rates err on the moderate side. The rapid ebb and flow of the tides has an influence in the bacteriology of the oysters within the harbour.

Varicella vaccination is optional and requires self-payment. On 1 December 2018, Wuxi City launched a free varicella vaccination program for children. This study aimed to evaluate the changes in varicella incidence before and after the implementation of the policy. The data were obtained from official information systems and statistical yearbooks. We divided the period into chargeable (January 2017 to November 2018) and free (December 2018 to December 2021) periods. Interrupt time series analysis was used to conduct a generalised least-squares regression analysis for the two periods. A total of 51,071 varicella cases were reported between January 2017 and December 2021. After the implementation of the policy, there was a statistically significant decrease in the incidence of varicella (β2 = −0.140, P = 0.017), and the slope of the incidence also decreased by 0.012 (P = 0.015). Following policy implementation, the incidence decreased in all age groups, with the largest decline observed among children aged 8–14 years (β2 = −1.109, P = 0.009), followed by children aged ≤7 years (β2 = −0.894, P = 0.013). Our study found a significant reduction in the incidence of varicella in the total population after the introduction of free varicella vaccination in Wuxi City.

The effects produced upon bacteria by environmental conditions constitute factors which until recently have been studied with but too little regard to scientific accuracy, even by the bacteriologist investigating the conditions under which pathogenic bacteria occur in nature, and whilst probably leading a saprophytic existence.

1. When GDVII virus was injected into the brains of mice, subsequent intracerebral injections of mixed pertussis and diphtheria prophylactic significantly shortened the incubation period. Subsequent intramuscular injections of mixed prophylactic had no influence on the course of the infection.

2. Intramuscular inoculation of either GDVII virus or EMC virus results in a marked localization of paralysis in the injected limb. With GDVII virus, the localization probably arises from the use of the sciatic nerve route for entry into the c.n.s., and is unaffected by injection of substances into the opposite limb. With EMC virus, localization can be modified by injections into the opposite limb.

3. When GDVII or EMC virus was injected by a peripheral route other than intramuscular, intramuscular injections of vaccines or normal mouse brain suspension induced localization of paralysis in the injected limb.

4. Intramuscular inoculation of vaccines increased mortality in mice injected into the same limb muscle with GDVII virus. Within the limits tested the later the vaccines were injected relative to the virus, the greater was the effect.

5. When the vaccines used were more than a few months old, this facilitating effect was replaced by a protective effect. Mice injected intramuscularly with aged vaccines were significantly more resistant than the controls to GDVII virus injected into the same muscle.

6. Intracerebral inoculation of vaccines, and to a lesser extent other substances, increased mortality in mice which had received intramuscular inoculations of GDVII virus, by allowing virus to pass directly from the blood into the brain. This resulted in a predominance of cerebral symptoms when the vaccines were injected immediately after the virus, but not when the interval was lengthened to 48 hr.

7. The mode of action of modifying factors in neurotropic virus infections is discussed in the light of these results.

This work was done in the Department of Zoology, Oxford University, during the tenure of a grant from the Medical Research Council. I also wish to thank the Nuffield Foundation for their support of the virus research carried on in the Department.

I am most grateful to Dr F. K. Sanders for his advice and criticism, as well as for provision of technical facilities, and to Dr Donald Michie for assistance with the statistical treatment of the data, and for much other help.

Previous studies of boys at Christ's Hospital school have indicated that annual immunization with influenza virus vaccines did not significantly reduce the total incidence of influenza infection compared to unimmunized subjects. In view of the implications of this result, a similar study was conducted in ferrets to clarify these findings. Groups of ferrets were immunized or infected with a series of influenza A (H3N2) viruses over an 18-month period, and the immunity to subsequent live virus challenge was measured after each virus or vaccine exposure. The results indicated that live virus infection gave a more solid immunity than immunization with inactivated vaccine; and the serum haemagglutination-inhibiting antibody response was greater following immunization than following infection. In addition, differences in immunity could not be explained by measurements of cross-reacting and specific antibody, since the incidence of these antibodies was similar in both infected and immunized animals. The results do not suggest an explanation for the different levels of immunity induced following infection or immunization or the results obtained from the Christ's Hospital study. However, the relative contribution of various immune responses to virus or virus antigen is discussed, and it is suggested that the difference in immunity may lie in the ability of live virus infection to stimulate local antibody.

The action of air containing nitrogen peroxide upon flour, in quantities up to 300 c.c. of nitrogen peroxide to one kilogramme of flour, may be summarised as follows:—

I. The golden-yellow tint of the flour is destroyed. Immediately after bleaching no difference in tint due to excess of the bleaching agent could be observed with Lovibond's tintometer, but on keeping for several days the more highly bleached samples became decidedly yellow, while those treated with 30 to 100 c.c. of nitrogen peroxide per kilogramme became still whiter, the maximum of bleaching effect being attained within these limits.

II. The amount of nitrous acid or nitrites present in a freshly bleached flour is approximately proportional to the amount of nitrogen peroxide employed, and corresponds to about 30% of the total nitrogen absorbed, rising to 40% in the more highly bleached samples. After the lapse of several days, the proportion of nitrites present decreases considerably in the higher concentrations, but remains very nearly the same in the more slightly bleached samples.

III. Approximately 60% of the total nitrogen introduced as nitrogen peroxide into the flour during bleaching can be recovered as ammonia a short time after bleaching by reducing the aqueous extract of the flour with a copper-zinc couple, and may be assumed to be present in the flour as nitric and nitrous acids or as nitrates and nitrites. After keeping the bleached flour for some days the amount of nitric acid extracted with cold water decreases. Experiments with pure glutenin and gliadin indicated that in certain circumstances nitric acid may be withdrawn from solution or “adsorbed” by these proteins.

IV. In highly bleached flour a considerable increase in the amounts of soluble proteins and soluble carbohydrates takes place. If one kilogramme of flour is bleached with 300 c.c. of nitrogen peroxide, the amount of soluble nitrogen is doubled. This appears to be due almost entirely to the solubility of gliadin in nitric acid of certain concentrations. The simultaneous increase of soluble carbohydrates would seem to point to an intimate relationship between the gliadin and certain carbohydrates in flour.

V. If highly bleached flour is allowed to stand for some time after bleaching, the oil undergoes very considerable alteration and acquires the characteristics of an oxidised oil. About 6 to 7% of the nitrogen introduced as nitrogen peroxide during bleaching is absorbed by the oil.

VI. The absorption of nitrogen peroxide by flour does not appear to be accompanied by the production of free nitrogen, nor was any evidence obtained of the formation of diazo-compounds.

VII. Sodium nitrite was found to exert no inhibitory action on the digestion of soluble starch by saliva, but the rate of digestion was greatly retarded if the starch had been previously treated with nitrogen peroxide gas. Bleaching was found to exercise an inhibitory effect on the salivary digestion of flour.

During the experimental comparison of different types of hot-water heating systems in a school at Easter 1934 about a thousand kata readings were taken. These were taken mostly in pairs, one immediately after the other, and a third reading was taken only when the first two differed by more than about 10 per cent.