Colony counts on mice given the same number of Salmonella always differ considerably. However, the standard error of the mean log count does not increase after the first 1·5 hr. of infection until the 8th or 10th day. These infections therefore appear to pass through an initial stage lasting a few hours, in which a varying proportion of the inoculum is killed, followed by a prolonged second stage in which the scatter in individual colony counts remains constant.

The prevalence of specific HSV-2 antibodies was studied in Tanzanian and Norwegian sexually transmitted disease (STD) patients (1095) and non-STD patients (488). Correlates to demographic and behavioural factors were evaluated. Seropositivity was determined by the non-commercial peptide-55 enzyme-linked immunoassay. The prevalence of HSV-2 antibodies was 70% in Tanzanian and 17% in Norwegian STD patients, 35% in Tanzanian blood donors and pregnant women, and 4, 7 and 14% in Norwegian medical students, blood donors and pregnant women respectively. A higher HSV-2 prevalence was associated with female sex, increasing age, previous STDs, history of genital HSV infection, coitarchal age (age at first intercourse) <15 years and HIV seropositivity. Compared to previous data, the prevalence of HSV-2 antibodies in Tanzanian STD patients has increased remarkably. In Norwegian STD patients our results are consistent with, or lower than, the prevalence previously reported in Western Europe. Demographic rather than behavioural factors were associated with higher prevalence of HSV-2 antibodies in STD patients.

Aquatic wild birds are often carriers of low-pathogenic avian influenza viruses (LPAIVs). If H5 and H7 LPAIVs are transmitted to poultry and have the opportunity to circulate, a highly pathogenic AIV may arise. Contact with aquatic wild birds is one of the most important ways in which these LPAIVs can be introduced into poultry flocks. In this study, the transmissibility of a duck-originated H5 LPAIV between ducks and chickens was analysed in a series of animal experiments, using different transmission routes. Results indicate that the outcome of virus intake by chickens exposed to infectious ducks depends on the way the virus is presented. Faecally contaminated drinking water proved to be the most efficient route by which the virus can be transmitted to chickens. The results from this study also suggest that some duck-originated H5 LPAIVs may be introduced to poultry but do not have the potential to become established in poultry populations.

Selenite F broth prepared in the laboratory from single ingredients was found to be significantly more efficient than nutrient broth in the isolation of Shigella sonnei from human faeces. It was more efficient than direct plating on deoxycholate citrate agar for diagnosing Sonne dysentery in a local outbreak. The difference was significant. There was, however, no significant advantage for enrichment over direct plating when stools posted from Bristol to Cardiff were examined.

Laboratory prepared selenite F broth was preferable to the same medium purchased commercially from two different firms. The product of one firm was significantly better than that of the other.

Two methods of sterilization of laboratory prepared selenite F broth were studied. Seitz filtered selenite was less inhibitory to the growth of small numbers of Shigella sonnei. Sterilization by heating in free steam for periods of 15 mm and over impaired the ability of selenite F broth to allow multiplication of small numbers of Shigella sonnei.

Public Health England conducts enhanced national surveillance of tetanus, a potentially life-threatening vaccine-preventable disease. A standardized questionnaire was used to ascertain clinical and demographic details of individuals reported with clinically suspected tetanus. The 96 cases identified between 2001 and 2014 were analysed. The average annual incidence was 0·13/million (95% confidence interval 0·10–0·16) of which 50·0% were male. Where reported, 70·3% of injuries occurred in the home/garden (45/64). Overall, 40·3% (31/77) cases were in people who inject drugs (PWID), including a cluster of 22 cases during 2003–2004. Where known (n = 68), only 8·8% were age-appropriately immunized. The overall case-fatality rate was 11·0% (9/82). All tetanus-associated deaths occurred in adults aged >45 years, none of whom were fully immunized. Due to the success of the childhood immunization programme, tetanus remains a rare disease in England with the majority of cases occurring in older unimmunized or partially immunized adults. Minor injuries in the home/garden were the most commonly reported likely sources of infection, although cases in PWID increased during this period. It is essential that high routine vaccine coverage is maintained and that susceptible individuals, particularly older adults, are protected through vaccination and are offered timely post-exposure management following a tetanus-prone wound.

Diagnosing streptococcal pharyngitis in children on the basis of clinical appearance and throat culture is complicated by high colonisation rates and by the ability of other pathogens to cause clinically similar disease. To characterise the epidemiology of Lancefield Group A, C and G β-haemolytic streptococcus (GAS, GCS and GGS, respectively) in children, we conducted a 2-year prospective study of 307 school children between 7 and 11 years old. GGS and GAS were commonly identified organisms both for silent streptococcal colonisation and symptomatic sore throat, while GCS was uncommonly found. Streptococcal culture positivity at the time of clinical pharyngitis was estimated to reflect true streptococcal pharyngitis in only 26% of instances, with the frequency varying from 54% for children rarely colonised to 1% for children frequently colonised. Numerous GAS emm types were identified, including several types previously associated with severe pharyngitis (e.g. emm types 1, 3 and 28). No severe complications were seen in any child. These data suggest that the clinical diagnosis of streptococcal pharyngitis is likely to remain difficult and that treatment decisions will remain clouded by uncertainty. There remains a need for organism-specific rapid point-of-care streptococcal diagnostic tests and tests that can distinguish between streptococcal colonisation and disease.

There seems to be considerable evidence in favour of the view that the immediate cause of this acute infective fever is an organism in the form of a streptococcus although there does not yet appear to be unanimity as to the specific characteristics of the latter. With regard to the secondary or indirect or predisposing causes of the complaint, the agencies which influence favourably the development and activity of the organism and consequently the prevalence of the disease, there has been a definite tendency in recent years not only to abandon the hitherto prevailing opinion on the influence of certain meteorological factors, namely, that increase in the amount of rainfall and decrease in the temperature are generally associated with increased incidence of the disease but even to assert that the action of these factors is the reverse of this.

The serological characters of 66 strains of meningococci obtained from the cerebro-spinal fluid in cases of meningitis have been studied. Serological tests of a similar nature have been applied to 86 strains of Gram-negative cocci, culturally identical with meningococci, obtained from the naso-pharynx of non-contacts. The two series have been compared in respect of agglutinability, agglutinogenic capacity, and absorptive capacity with the following results:

The majority of the spinal strains can be divided into two main groups by simple agglutination tests with selected spinal sera: about 27 can be assigned to Group I and 34 to Group II, the remaining five being relatively inagglutinable or equally agglutinated by sera of both groups.

During 2012 real-time syndromic surveillance formed a key part of the daily public health surveillance for the London Olympic and Paralympic Games. It was vital that these systems were evaluated prior to the Games; in particular what types and scales of incidents could and could not be detected. Different public health scenarios were created covering a range of potential incidents that the Health Protection Agency would require syndromic surveillance to rapidly detect and monitor. For the scenarios considered it is now possible to determine what is likely to be detectable and how incidents are likely to present using the different syndromic systems. Small localized incidents involving food poisoning are most likely to be detected the next day via emergency department surveillance, while a new strain of influenza is more likely to be detected via GP or telephone helpline surveillance, several weeks after the first seed case is introduced.

In November 2016, a woman in her 30s who stayed at an insecure, temporary housing facility, a manga café in Tokyo, Japan, for a year was diagnosed with sputum smear-positive tuberculosis (TB). Since the café had 31 staff members and provided with accommodation to many people, the local health office initiated a contact investigation. This study aims to characterise the cases found in the outbreak. A TB case was defined as a person tested bacteriologically positive for TB, or was determined to have TB by a physician. A latent TB infection case was defined as a person tested positive by interferon-γ release assay. From January 2016 through November 2017, there were 31 staff members at the manga café, of which, six developed TB disease (one smear-negative, culture-positive and five smear- and culture-negative) in addition to seven LTBI. Another long-term customer was found having sputum smear-positive TB. Variable numbers tandem repeat (VNTR) test revealed that the index patient and the long-term customer had the identical type of VNTR; however, one staff member had a different VNTR. Local health authorities should intensify screening long-term customers of such facilities for TB regularly as well as once a TB outbreak occurs.

Coronavirus disease 2019 (COVID-19) has had a tremendous impact in China and abroad since its onset in December 2019 and poses a major threat to human health. Healthcare workers (HCWs) are at the forefront of the response to outbreaks. This study reviewed literature data and found that HCWs were at high risk of infection during the COVID-19 pandemic, especially at the early stage of the epidemic, and many factors greatly affected their occupational safety. Although SARS-CoV-2 transmission was controlled in China, the Chinese experience can help protect HCWs from COVID-19 and other respiratory diseases.

The administration per-orally to mice of the non-absorbable antibiotics polymyxin E, tobramycin and amphotericin B resulted in the elimination of detectable aerobic gram-negative rods from the faecal flora without affecting the total viable aerobic count. The addition of parental cefotaxime to the regime caused a fall in the number of aerobic lactobacilli and an increase in the number of enterococci. The rise was associated with the translocation of viable enterococci to the mesenteric lymph nodes and the spleen. The changes induced by cefotaxime were reversed when the antibiotic was withdrawn. Following withdrawal of all antibiotics the total aerobic faecal flora increased to above normal levels, but there was no associated diarrhoea. Attempts to implant exogenous enterobacteria into the digestive tract resulted in only low level colonization both in treated mice and in control mice. These results may have implications for the use of this antibiotic regime for selective decontamination of the digestive tract in humans, particularly those who are immunocompromised.

Hepatitis B virus (HBV) infection is endemic in Turkey, but the main routes of transmission were not well established. This study aims to detect the exposure time to HBV and associated risk factors among children. In a sampling group of chıldren aged 0–19 years living in Edirne, antiHBc, antiHBs and HBsAg were screened by the microELISA method. A questionnaire was also completed for each child. In 717 children that were included in the study, the total antiHBc seropositivity was 5·4% and was 1·8, 0·8, 1·7, 6·8, 11·8% in 0–1, 2–5, 6–10, 11–14, 15–19 years age groups respectively. The overall HBsAg seropositivity was 1·7%. The risk of HBV infection increased after the age of 10 years (OR 7·79, 95% CI 3·01–20·16). Collective circumcision was the only independent factor according to regression analysis. Children living in Edirne should be vaccinated against HBV before reaching 11 years of age.

Antibiotic resistance plasmids from organisms that had caused serious epidemics, including those responsible for epidemics of chloramphenicol-resistant typhoid fever and dysentery in Central America, were transferred to a strain of Salmonella typhimurium and of Salmonella gallinarum. The virulence and infectivity of these R+ forms were then compared with the R− parent forms in orally inoculated chickens.

None of the R+ forms were more virulent than their R− parent forms. The mortality rates they produced were either the same as or less than that of their R− parent forms. The mortality rates were not increased by feeding the chickens on diets containing antibiotics against which the plasmids provided resistance.

The removal of the plasmids from some R+ forms of decreased virulence was not accompanied by any alteration in virulence, indicating that they were less virulent mutants of the parent strain that had conjugated preferentially. In other cases their virulence was increased, indicating that the very possession of the plasmid was involved in their decreased virulence. Of four forms of the S. gallinarum strain harbouring the plasmid that had been incriminated in the Central American dysentery outbreak, one was as virulent as the parent R− form and the other three were less virulent. Preferential conjugation by an avirulent mutant was responsible for the lack of virulence of one of them but the very possession of the plasmid appeared responsible for the decreased virulence of the other two. The decreased virulence of de-repressed F+ and I+ forms of the S. typhimurium strain was increased to that of repressed F+ form and of the parent form by plasmid removal.

Organisms of the R+ forms of the S. typhimurium strain were not excreted in larger amounts or for longer periods of time by infected chickens than organisms of the R− parent form were. Neither did organisms of the R+ forms of this strain or the S. gallinarum strain spread more rapidly or more extensively from infected chickens to in-contact chickens than organisms of the R− parent forms did. When antibiotics against which the infecting R+ organisms provided resistance were included in the diet of these chickens the R+ organisms were usually excreted in greater amounts, for longer periods of time and spread more rapidly and more extensively from the infected chickens to the in-contact chickens.

Techniques for the fractionation of C′ 1 and C′ 2, and for the specific inactivation of C′ 4 of horse complement are described, and shown to be satisfactory. These three components of complement and also conglutinin are found to be essential to the process of conglutination.

The experiments reported do not exclude the possibility of additional or unidentified fractions of horse serum playing a part in the reaction. Whether or not C′ 3 is essential to the process of conglutination could not be determined from the evidence available.

It was found that by the procedures employed the C′ 4 fraction may be supplied either from the horse complement or from the heated bovine serum added as a source of conglutinin or from both.

When horse complement and bovine antibody against sheep cells are used it is found that conglutination will only result when the complement components are absorbed on to the immune complex in a particular sequence. The sequence is that C′ 1 is absorbed first on to the sensitized cells, and then C′ 2 and C′ 4 are absorbed together. Both these components must be presented together to the sensitized cells carrying C′ 1 if conglutination is to result. Finally, conglutinin acts on the sensitized cells which have absorbed the three complement components, and conglutination results.

The significance of these findings, together with matters of a more general nature, is discussed.

1. The growth in synthetic cream of certain pathogenic bacteria may be inhibited by two methods:

(a) By limiting the ingredients to cooking fat or other fatty material, excluding margarine or butter, emulsifying agent such as methyl cellulose, sugar and salt. The cream must not then be left in contact with confectionery from which nutritive material may be absorbed. This last condition renders the method impracticable as a means of control.

(b) By the addition to synthetic cream, including those containing milk and egg, of a bacteriostatic agent such as hydrogen peroxide.

2. Contaminants may grow in emulsified fats in the absence of protein. These are probably lipolytic organisms which are able to utilize the products split from the fat. Organisms such as coagulase-positive staphylococci, Salmonella paratyphi B, and Bacterium coli, tend to die out within 24 hr. or after a few days in creams lacking protein.

3. The concentration of H2O2 necessary to inhibit the growth of test organisms is dependent on the ingredients of the cream. In the presence of butter, milk and egg yolk at least three times the concentration of H2O2 is necessary as when emulsified fat without added protein is used. The suggestion is made that concentrations of H2O2 from 0·005 to 0·02% should be added to all commercially produced synthetic cream, the actual concentration used depending on the constituents of the cream.

4. To prevent the growth of contaminating organisms in commercially produced synthetic cream, H2O2 should be added immediately after pasteurization and cooling when the bacterial count is still low. Even comparatively high concentrations of H2O2 will not inhibit or control the growth of bacteria already present in large numbers.

5. The inhibiting power of 0·012% of H2O2 remained effective in a fat-emulsion cream and also in a laboratory cream containing margarine, egg and milk for 3 weeks at + 4 and 20° C.; at higher temperatures of storage the stability of the oxidizing agent is doubtful.

6. Since synthetic cream is exposed to so many different sources of contamination, particularly in the bakery, and since there is no method of controlling the growth of pathogenic organisms that have gained access to it other than by the addition of a bacteriostatic agent, it is strongly recommended that the present regulations on preservatives should be altered to allow the addition of H2O2 in suitable concentration to synthetic cream.

We are grateful to all those who have helped in the supplies of material, and in particular we wish to thank the Public Health Department, St Pancras Town Hall; Mr E. Capstick, United Dairies Ltd.; Mr J. Valentine Backes, President, Bakery Allied Traders' Association; and also Messrs Bakcos Catering Supplies Ltd., A. Bellamy and Co. Ltd., Farma Cream Products Ltd., Krema Ltd., Malga Products Ltd., Ramsay, Braddon and Co. Ltd., Quality Foods Ltd., Sunnyside Products Ltd., Unicream Ltd., and Vitacream Ltd.

We are indebted to Mr L. Bailey for his technical assistance.

A peptide library was used to screen for regions containing potential linear B-cell epitope sites in the glycoproteins and nucleoprotein of Crimean-Congo haemorrhagic fever virus (CCHFV) in an enzyme-linked immunosorbent assay (ELISA). The library consisted of 156 peptides, spanning the nucleoprotein and mature GN and GC proteins in a 19-mer with 9-mer overlap format. Using pooled serum samples from convalescent patients to screen the library, six peptides were identified as potential epitope sites. Further testing of these six peptides with individual patient sera identified two of these peptides as probable epitope sites, with peptide G1451–1469 reacting to 13/15 and peptide G1613–1631 to 14/15 human sera. These peptides are situated on the GC protein at amino acid positions 1451–1469 (relative to CCHFV isolate SPU103/97) (TCTGCYACSSGISCKVRIH) and 1613–1631 (FMFGWRILFCFKCCRRTRG). Identified peptides may have application in ELISA for diagnostic or serosurveillance purposes.

Recent epidemiological data suggest a link between the consumption of bovine offal products and Shiga toxin-producing Escherichia coli (STEC) infection in Japan. This study thus examined the prevalence of STEC in various types of these foods. PCR screened 229 bovine offal products for the presence of Shiga toxin (stx) gene. Thirty-eight (16·6%) samples were stx positive, of which eight were positive for rfbEO157 and three were positive for wzyO26. Four O157 and one O26 STEC isolates were finally obtained from small-intestine and omasum products. Notably, homogenates of bovine intestinal products significantly reduced the extent of growth of O157 in the enrichment process compared to homogenates of beef carcass. As co-incubation of O157 with background microbiota complex from bovine intestinal products in buffered peptone water, in the absence of meat samples, tended to reduce the extent of growth of O157, we reasoned that certain microbiota present in offal products played a role. In support of this, inoculation of generic E. coli from bovine intestinal products into the homogenates significantly reduced the extent of growth of O157 in the homogenates of bovine intestinal and loin-beef products, and this effect was markedly increased when these homogenates were heat-treated prior to inoculation. Together, this report provides first evidence of the prevalence of STEC in a variety of bovine offal products in Japan. The prevalence data herein may be useful for risk assessment of those products as a potential source of human STEC infection beyond the epidemiological background. The growth characteristic of STEC O157 in offal products also indicates the importance of being aware when to test these food products.

1. Our experiments show that an intravenous injection of antigen immediately after an intravenous injection of antiserum in the guinea-pig were followed by:

(a) Acute shock and death within 5 min. The signs and post-mortem appearances were indistinguishable from acute anaphylactic shock as typically seen in the guinea-pig. Some control animals injected with antiserum only died in a way similar to those which received both antiserum and antigen. These are discussed in detail in the body of the paper.

(b) Delayed shock and death some hours later. The post-mortem appearances were those of gastro-intestinal congestion and haemorrhage resembling the changes seen in dogs dying of anaphylactic shock. Such changes were never seen in the control animals.

(c) Recovery. Practically all the animals which recovered had symptoms of respiratory embarrassment immediately following the injections of anti-serum and antigen and many had later symptoms of abdominal shock. The animals which were given an injection of antiserum only rarely had any symptoms and never abdominal symptoms.

2. It is necessary to test the antisera used by control inoculation since some antisera are toxic.

Like the skin and its appendages, the teeth, nails and hair, so also other tissues of ectodermal origin are here shown to be affected by fluorine. The action of fluorine consists in lowering the level of the calcium in the blood and tissues. The epithelia of the mouth and the salivary glands, of the nasopharynx, the conjunctivae and the lachrymal glands may be affected. Signs and symptoms are thus produced which are closely similar to those usually attributed primarily to infection. It is suggested that an infection accompanying chronic fluorine poisoning is of a secondary nature, and that it is brought about by the loss of calcium in the body.