Semi-purified elementary body suspensions, prepared or preserved in three different ways, have been compared as to their species-specific CF-activity as revealed both against Bedsonia-negative sera of trachoma patients (of known stage), and against psittacosis-positive sera of men and animals.

Two of these antigens (the SPG-formol-antigen and the SPG-glycerol-antigen) revealed a positive species-specific CF-reaction in 61–100% of the Bedsonia-negative serum samples obtained from trachoma patients, with titres ranging from 1/2 to 1/128.

Various parameters (as percentage proportion of positive reactors, CF-titre, duration of the disease, clinical stage of trachoma, etc.) have been analysed for correlation, and the results obtained with the different antigens are compared with one another.

The most useful of the three antigens, showing a good species-specific CF-reactivity and no anticomplementary activity, was found to be the ‘SPG-formolantigen’. However because of its group-specific reactivity, for detection of species-specific trachoma antibodies in routine, it could be used only with Bedsonia-negative samples of sera. Because of the thermolability of its species-specific component, the SPG-formol-antigen proved to be liable to deterioration.

We have pleasure in thanking to Dr F. B. Gordon for help in procuring bibliography and the viable strain of trachoma virus. We wish to express our thanks also to Mrs R. Šepetavic and to Miss M. Krečo for their technical assistance.

Calculations have been carried out which indicate that poliovirus vaccine contains sufficient antigen to account for the observed antibody response.

1. The production of weaned young from pairs or groups of three, four and five mice, each containing one male, has been compared.

2. For long-term large-scale production, small breeding groups of one male with two females are proposed.

I should like to thank Dr A. S. Parkes, F.R.S., for much helpful criticism, and Dr Walter Perry for the statistical tests.

Dilution had an adverse effect on the infectivity of 24 h cultures of a strain of Fusobacterium necrophorum, which became apparent at or near the minimum lethal dose. Thus in mice inoculated subcutaneously the mortality produced by 0·01 ml of undiluted culture was almost invariably greater than that produced by 0·1 ml of a 1 in 10 dilution. The explanation appeared to lie in the increased physical separation of bacterial cells that was the inevitable consequence of dilution.

Investigations of the biological properties of tick-borne encephalitis viruses immediately after isolation from naturally infected Ixodes persulcatus from Western Siberia has revealed their different pathogenicity for monkeys and mice. Strains highly pathogenic for mice on extraneural inoculation and for rhesus monkeys on intracerebral inoculation have been isolated, but also strains with a low extraneural pathogenicity for mice and a complete non-pathogenicity or a mild pathogenicity for monkeys on intracerebral inoculation.

The viruses have been classified into three main groups by their virulence for mice and monkeys, and their ability to grow in tissue culture at 40° C. and the findings are summarized in Table 6. Group I included viruses highly virulent for mice by any route of inoculation, which caused fatal paralytic disease in monkeys, and which grew well in chick embryo culture at 40° C.

Group II strains also had a high virulence for mice, but in monkeys caused milder disease with a peculiar clinical course indicative of primary damage to the cerebellum. About half of the infected monkeys recovered completely or with mild sequelae (ataxia, pareses of the limbs). This group grew moderately well in chick embryo cultures at 40° C. Groups I and III differed essentially in their virulence for mice by subcutaneous inoculation, and virulence for monkeys decreased distinctly with transition from group I to group III. Group III strains showed a lower reproduction rate at 40° C. In chick embryo culture than group I. Groups I and II showed good correlation between extraneural pathogenicity for mice, pathogenicity for monkeys by IC inoculation, and growth rate in chick embryo cultures at 40° C.

Group I strains were isolated chiefly from foci with a high TBE morbidity and the strains of groups II and III in foci with sporadic cases. It is, however, highly probable that in any tick-borne encephalitis focus several variant strains of differing virulence exist.

Recent experience of vaccinating volunteers with naturally attenuated group III strains suggests that safe and effective live vaccines can be developed against tick-borne encephalitis. Vaccines against many other arbovirus diseases can probably also be derived from naturally occurring strains of virus isolated from arthropods in areas of low disease but high infection rate. This approach looks more promising than the usual approach of attempting to develop attenuated strains from highly virulent strains.

In Ethiopia, the magnitude of violence against girls during COVID-19 in the study area is not known. Therefore, this study aimed to assess the violence and associated factors during COVID-19 pandemic among Gondar city secondary school girls in North West Ethiopia. An institution-based cross-sectional study was conducted from January to February 2021. Data were collected from four public and two private Gondar city secondary schools. Investigators used stratified simple random sampling to select participants and the investigators used roster of the students at selected schools. Investigators collected the data using self-reported history of experiencing violence (victimisation). Investigators analysed data using descriptive statistics and multivariable logistic regression. Investigators invited a total of 371 sampled female students to complete self-administered questionnaires. The proportion of girls who experienced violence was 42.05% and psychological violence was the highest form of violence. Having a father who attended informal education (AOR = 1.95, 95% CI 1.08–3.51), ever use of social media 1.65 (AOR = 1.65, 95% CI 1.02–2.69), ever watching sexually explicit material (AOR = 2.04, 95% CI 1.24–3.36) and use of a substance (AOR = 1.92, 95% CI 1.17–3.15) were significantly associated variables with violence. Almost for every five girls, more than two of them experienced violence during the COVID-19 lockdown. The prevalence of violence might be under reported due to desirability bias. Therefore, it is better to create awareness towards violence among substance users, fathers with informal education and social media including user females.

A total of 1203 unselected routine faecal samples from 1006 patients were cultured for Yersinia species by a cold enrichment technique. Seventy-five specimens (6·1%) from 63 patients were culture-positive for Yersinia spp. Fifty-two were Yersinia enterocolitica, 22 Yersinia frederiksenii and 1 Yersinia intermedia. The predominant Y. enterocolitica isolates belonged to biotype 1 – serotype 0:6, 30 or serotype 0:5, 27. Y. frederiksenii strains were non-typable. Forty isolates were recovered from 33 patients with gastroenteritis. During the study period 83 Salmonella spp. from 33 patients, 17 Shigella sonnei from 13 patients and 13 Campylobacter jejuni from 12 patients were cultured. Yersinia spp. was isolated in association with salmonella on three occasions, twice with rotavirus and once each with Shigella sonnei, Campylobacter jejuni and Trichuris trichiura.

The study arose from the recent finding that sub-lethal numbers of certain bacterial species greatly enhanced the infectivity of Fusobacterium necrophorum.

A severe F. necrophorum infection in mice, cured with metronidazole, produced significant though slight resistance, which was demonstrable by challenge with a minute dose of F. necrophorum (< 20 organisms) suspended in a sub-lethal dose of Escherichia coli (300 × 10 organisms) to enhance fusobacterial infectivity. In an earlier comparable experiment, challenge with F. necrophorum alone, in necessarily large doses (≥3 × lO organisms), failed to demonstrate that a single cured fusobacterial infection gave rise to resistance; such an infection neither protected against the fatal necrobacillosis produced by challenge nor prolonged survival.

A sub-lethal E. coli infection was also shown by challenge with a minute dose of F. necrophorum (< 10 organisms), suspended in a sub-lethal dose of E. coli (152 × 10 organisms), to produce significant though slight protection against necrobacillosis.

The degrees of resistance demonstrated were too slight to give any encouragement to the prospect of an effective necrobacillosis vaccine.

The use of neutral-red culture media has recently been suggested for the detection of B. coli in water supplies. Rothberger (1) grew a number of organisms on media containing various organic dyes, and found that while some species were able to bring about a reduction of the colouring matter in the medium, others produced no change. This difference in reaction was particularly marked in the case of B. typhosus and B. coli in media containing neutral-red. B. coli casused the reduction of the neutral-red to yellow with green fluorescence, whilst B. typhosus produced no change of colour beyond an occasional fading of the red. After testing a number of races of B. coli and B. typhosus, Rothberger proposed neutral-red media for the differentiation of the two organisms. Scheffler (2) confirmed in the main the work of Rothberger, and further observed that the reaction is by no means specific for B. coli. In addition to a number of bacterial species not commonly found in water, which gave the reaction, Scheffler found 3 of 13 organisms in spring and river waters, and 8 of 18 intestinal organisms from man which, though not belonging to the colon group, gave the neutral-red reaction.

The aim of this study was to determine the prevalence of gastroenteritis among children aged 4 years in South Australia. A cross-sectional survey of 9543 South Australian children aged 4 years was undertaken. Parents completed a questionnaire on behalf of their child who had attended a pre-school health check in 1998. The questionnaire covered gastrointestinal and respiratory symptoms experienced by the child in the previous 2 weeks and other risk factors for gastroenteritis. The 2-week prevalence of gastroenteritis among 4-year-old children was 14·2%. The major risk factors for gastroenteritis were presence of persons who had gastroenteritis inside the home, contact with persons who had gastroenteritis outside the home, antibiotic use and sore throat. Medical attention was sought for 20% of children who had gastroenteritis. Gastroenteritis is a significant cause of morbidity among young children and presents a considerable burden on the community. A substantial proportion of these occurrences of highly credible gastrointestinal symptoms may be manifestations of respiratory infections.

Diarrhoeal illnesses are the most frequent of notifiable diseases in Aragon. Physicians notify diarrhoea cases with presumed infectious origin on a weekly basis. Following an increase in 2005–2006, we aimed to identify the responsible organism(s) in order to inform control measures. We described seasonality of diarrhoea notifications for 1998–2004 and 2005–2006. We calculated correlations between diarrhoea notifications and enteric pathogens diagnosed in two Aragonese laboratories, and applied linear regression using coefficients of determination (r2). In 2005–2006 the winter peak of diarrhoea notifications increased from 2494 to 3357 weekly cases (34·6%) and the peak in Rotavirus diagnoses from 15 to 39 weekly cases. The correlation of diarrhoea notifications with Rotavirus was 0·05 in 1998–2004 and 0·42 in 2005–2006. The model for 1998–2004 included Salmonella enterica, Giardia lamblia and Clostridium difficile (r2=0·08) and for 2005–2006 Rotavirus and Astrovirus (r2=0·24). Our results suggest that Rotavirus contributed to the increase of diarrhoea notifications. We recommend determining the disease burden of Rotavirus in order to guide vaccination policies.

Milk from 150 local mothers has been assayed for bacteriostatic activity for milk-sensitive and milk-resistant indicator strains of Escherichia coli. Activity is greatest in colostrum which is active directly against all strains of E. coli. One week after delivery of the baby, milk is active against the milk-sensitive strain and becomes active against the milk-resistant strain in the presence of physiological amounts of bicarbonate and iron-binding protein. This activity decreases within 2–4 days on keeping milk unheated at 4 °C but is preserved for at least 4 months and often up to 2 years in milk heated to 56 °C then stored at 4 °C or in milk frozen, unheated, at −28 °C provided it is not repeatedly thawed and frozen. Later lactation milks are usually indistinguishable in activity from 1-week post-partum milk but may be less stable on storage particularly if frozen. Lyophilization in vacuo preserves activity of early-lactation milk for at least 6 months.

Heating milk to above 65 °C causes a progressive loss of activity which can be partially restored by adding bicarbonate and iron-binding protein. Iron abolishes the activity of milk and reduces that of colostrum.

1. Examination of nine type strains of Brucella, collected from various sources, by agglutination and the absorption of agglutinin test revealed distinct serological difference between Br. abortus and Br. melitensis. Differentiation could only be made by the agglutinin-absorption test, both organisms agglutinating equally with abortus or melitensis immune sera.

2. By agglutination alone differentiation could be made between a group consisting of Br. melitensis and Br. abortus strains on the one hand and a group which included one strain labelled Br. melitensis, one labelled Br. abortus, and Br. paramelitensis.

3. The agglutinin-absorption test showed that this Br. paramelitensis group comprised two strains of closely allied paramelitensis strains, and that the Br. abortus strain could be regarded as a Br. para-abortus strain.

4. Serological investigation of eight strains of Brucella isolated from patients suffering from undulant fever in Southern Rhodesia showed that six were serologically identical with type Br. abortus and two identical with what is regarded as a Br. para-abortus strain.

5. It is suggested that the melitensis-abortus group represent the “S” normal types, whereas the paramelitensis-para-abortus group represent the “R” mutant types of organisms.

1. The results of 192 blood cultures in an epidemic of enteric fever are analysed. The epidemic was caused by a double enteric infection with Salm. typhi (Vi-phage type T) and Salm. paratyphi B (Vi-phage type ‘Dundee’).

2. All of sixty –five cultures between 102 and 104∘ F. were positive, and a significant number of positive cultures at lower body temperatures were obtained. Three out of four cultures, taken when the temperature was subnormal, were positive. In seventy–one out of seventy–six cases (93·4%) a positive blood culture was obtained.

3. The highest percentage of positive isolations was obtained in the second week of disease. In the severe cases the highest percentage occurred in the third week. The reasons for this, and the findings of previous studies, are discussed.

4. No difficulty was encountered in obtaining positive blood cultures in previously inoculated individuals.

5. The average period of incubation of the cultures, required to produce a positive result, was 4–5 days, and 17% did not become positive until the ninth to eleventh day of incubation.

6. The discovery of ehloramphenicol has emphasized the need for the early diagnosis of enteric fever. This can most readily be achieved by the method of blood culture.

Monoclonal antibodies specific for rotavirus subgroup 1 (SG1) and subgroup 2 (SG2) were used to analyse by enzyme immunoassay (EIA) the subgroups of human rotavirus isolates obtained from three different parts of India during the period September 1985 to July 1987. We identified one isolate which failed to react with either SG1 or SG2 specific monoclonal antibodies, although it reacted well with a monoclonal antibody specific for group A rotaviruses. This finding suggests that it belongs to a new rotavirus subgroup. Further, another isolate was found to belong to SG1 although it had a ‘long’ electropherotype.

1. The rat population of a main sewer was studied by means of census baits.

2. In a series of poison treatments extending over 4–5 months all rats visiting the access points were eliminated.

3. At the end of this period the population was 40–65% of what it was at the beginning.

This work would not have been possible without the generous assistance once more of Mr A. R. J. Vickery, Assistant District Engineer of the Chief Engineer's Department of the London County Council and members of his staff, and without the ready co-operation of the Borough Engineer, the Medical Officer of Health and the Chief Health Inspector of the Metropolitan Borough of Bethnal Green, through which area the sewer ran.

Despite increasing migration, the impact of HIV epidemics from Central and Eastern Europe (C&EE) on the UK HIV epidemic remains small. C&EE-born adults comprised 1·2% of adults newly diagnosed with HIV in the UK between 2000 and 2007. Most C&EE-born women probably acquired their infection heterosexually in C&EE. In contrast, 59% of C&EE-born men reported sex with men, half of whom probably acquired their infection in the UK. Previously undiagnosed HIV prevalence in C&EE-born sexual-health-clinic attendees was low (2007, 0·5%) as was overall HIV prevalence in C&EE-born women giving birth in England (2007, <0·1%). The high proportion of men who have sex with men (MSM) suggests under-reporting of this group in C&EE HIV statistics and/or migration of MSM to the UK. In addition to reducing HIV transmission in injecting drug users, preventative efforts aimed at C&EE-born MSM both within their country of origin and the UK are required.

1. The weekly budgets of eighty out of ninety-nine families in four rural schools (containing 165 school children) and ninety-seven out of 200 families in one urban school (containing 183 school children) have been analysed.

2. Evidence is given that housewives, despite varying social status, spend between 9 and 11s. per man per week on food when the income is sufficient to allow this.

3. The lowest level of sufficiency in diet according to the instincts of the housewife is seen to correspond, at prices ruling in this district in the winter of 1936–7, with the cost of the diet of the British Medical Association Nutrition Report (1933) (7s. 8¾d.). This has been called standard A and compared with standard B costing 5s. 10¾d. which contains 1000 cal. and 13 g. of first-class protein a day less. Standard B is probably the lowest standard of diet which any authority would be prepared to recommend.

4. In the school in a prosperous urban district, in working class families (income not exceeding £4) where the children were fully embarked on the school period (i.e. the eldest child over 7 years but no child yet earning more than 10s. weekly), and which contained more than one child, 60% of children fell below standard A and 47·6% below standard B.

5. In the rural schools taking all the children, 72·2% were below standard A; where there was an income below 55s., 78% fell below standard A; below 40s. 85%; and below 35s. 91·7%. The figures below standard B were 40·6, 52·4, 60, and 75% respectively.

6. Both in urban and rural families, with the exception of high income groups (e.g. farmers), increase in the size of the family steadily lowers the allowance of food per unit. In medium wage earners the allowance of 9–11s. per unit per week when the family is small, is reduced to about 3s. when the family grows to a large size and before the first children begin to earn.

7. Most significant is the decline in the provision of first-class protein foods both in town and country in proportion as the family grows. Evidence is given that this contrasts markedly with the recognized needs of growth in childhood, and it is clear that in both town and country the large family in low wage groups produces a condition of extreme protein deficiency. Accepting 2s. per unit per week as a conservative estimate of the minimum expenditure upon first-class proteins, 13·2% of the school children in the urban school and 32·7% in the rural schools were subsisting on amounts suggesting protein starvation.

Ice-Cream has occasionally been proved to be the carrier of disease, and therefore a study of the ingredients used, the processes of manufacture and the bacterial content of the final product is an important branch of modern hygiene.

A tryptone-yeast extract medium enriched with glucose and serum incubated anaerobically at 41° C. was found to give a good yield of Staphylococcus aureus from air samples while suppressing the growth of 70–80% of the other airborne bacteria.

Our thanks are due to Miss S. M. Taber and Miss Patricia Wall, the Sisters in the wards where the air samples were collected, for their help. The investigation was financed from the Ministry of Health grant to St Mary's Hospital for the support of clinical research.