The bactericidal action of hexyl resorcinol vapour on airborne clouds of a variety of micro-organisms including pathogens and a virus has been investigated. In addition to killing rates comparable with those found by previous investigators, a phenomenon, which we have called the initial kill, has been demonstrated and experiments carried out to explain its mechanism. Under certain circumstances it enhances the elimination of viable bacteria very substantially.

We are indebted for technical assistance to Corporal J. C. G. Harris, R.A.F., to Messrs B. F. Courtnay and C. M. R. Pitman, and to members of the Virus Research and Field Trials Sections.

Reduction of the antioxidant capacity of plasma has been linked with the impairment of an effective immune response and so we hypothesized that the carriage rate of Neisseria meningitidis in asymptomatic subjects might correlate with the levels of antioxidants in plasma. To this end we took pharyngeal swabs from 339 children in Marquesado Basic Health Zone, Granada, Spain and in addition determined the total antioxidant capacity (TAC) in plasma samples from these subjects. The overall prevalence of N. meningitidis carriage was 5·9% (mean age 7·1 years) with rates of 10·3% in children aged ⩽3 years, 3·9% between 4 and 7 years and 2·4% in older subjects. Plasma TAC for the ⩽3-year-olds was 0·13 for carriers and 1·10 for non-carrier controls (P=0·04), 0·13 for carriers aged 4–7 years (controls 0·63) and 0·28 for carriers aged >7 years (controls 0·52). We analysed the association between TAC in plasma (<0·37 – 2 s.d.) and the carrier state of N. meningitidis. In the carrier state, the odds ratio for this association (TAC in plasma <0·25) was 8·44 (95% CI 1·5–48·9). These findings may suggest a reduced immune response in the host favourable to nasopharyngeal persistence of meningococci.

Drug-resistant paediatric tuberculosis (TB) is an overlooked global problem. In Italy, the epidemiology of TB has recently changed and data regarding drug-resistant forms in the paediatric setting is scanty. The aim of this case series was to report the cases of drug-resistant TB, diagnosed between June 2006 and July 2010 in four Italian tertiary centres for paediatric infectious diseases, in children and adolescents living in Italy. Twenty-two children were enrolled, of these 17 were resistant to one or more drugs and five had multidrug-resistant TB. All but one child were either foreign born or had at least one foreign parent. Twenty-one patients completed their treatment without clinical or radiological signs of activity at the end of treatment, and one patient was lost to follow up. The outcomes were good, with few adverse effects using second-line anti-TB drugs. Although this series is limited, it might already reflect the worrisome increase of drug-resistant TB, even in childhood.

Investigation of the viricidal effect of a mixture of ethylene oxide and carbon dioxide on two viruses, Columbia SK and vaccinia, yielded favourable results. Since ethylene oxide also exerts a germicidal effect, it offers simple and inexpensive disinfection of certain materials, especially those of low thermostability.

Some months ago Prof. M. J. Stewart (1933) gave an address on silicosis in which he covered the whole of the pathology of the various types of the disease. It may seem strange, therefore, that the same subject should be chosen for discussion so shortly afterwards. My apologia is that silicosis presents manysided problems and that since Prof. Stewart's paper appeared the claim has been ventured that the cause of silicosis has been demonstrated. Discussions have been taking place during the past twelve months at the Institution of Mining and Metallurgy—discussions stimulating in themselves and showing the necessity of further research along old and new avenues.

We investigated the virulence gene carriage and molecular type characteristics of Staphylococcus aureus isolates from bloodstream infections (BSIs) and skin and soft tissue infections (SSTIs) in children. A total of 71 isolates, 16 of which were methicillin-resistant S. aureus (MRSA), were investigated by PCR for virulence-associated gene profiles, sequence type and spa type. This revealed that 76·7% and 53·7% of the SSTI and BSI isolates, respectively, exhibited simultaneous carriage of ⩾10 virulence genes. Compared to BSI isolates, carriage rates for hla, hlb, cna, clfA, seb, sec and pvl genes were significantly higher in SSTI isolates. By contrast, carriage of eta, etb and sea was significantly higher for BSI isolates. Thirty-four sequence types (STs) and 36 spa types were identified in the 71 isolates and included 14 novel STs and four novel spa types. ST59-MRSA-IV/V-t437 was the most common clone in the MRSA isolates. We concluded that virulence determinants are widely distributed in isolates of S. aureus strains from children with BSIs and SSTIs, with an unexpectedly high rate in SSTI isolates. Future profiling of S. aureus virulence determinants may allow the prediction of severity and outcome for children with these infections.

Salmonella enterica serovar Wangata (S. Wangata) is an important cause of endemic salmonellosis in Australia, with human infections occurring from undefined sources. This investigation sought to examine possible environmental and zoonotic sources for human infections with S. Wangata in north-eastern New South Wales (NSW), Australia. The investigation adopted a One Health approach and was comprised of three complimentary components: a case–control study examining human risk factors; environmental and animal sampling; and genomic analysis of human, animal and environmental isolates. Forty-eight human S. Wangata cases were interviewed during a 6-month period from November 2016 to April 2017, together with 55 Salmonella Typhimurium (S. Typhimurium) controls and 130 neighbourhood controls. Indirect contact with bats/flying foxes (S. Typhimurium controls (adjusted odds ratio (aOR) 2.63, 95% confidence interval (CI) 1.06–6.48)) (neighbourhood controls (aOR 8.33, 95% CI 2.58–26.83)), wild frogs (aOR 3.65, 95% CI 1.32–10.07) and wild birds (aOR 6.93, 95% CI 2.29–21.00) were statistically associated with illness in multivariable analyses. S. Wangata was detected in dog faeces, wildlife scats and a compost specimen collected from the outdoor environments of cases’ residences. In addition, S. Wangata was detected in the faeces of wild birds and sea turtles in the investigation area. Genomic analysis revealed that S. Wangata isolates were relatively clonal. Our findings suggest that S. Wangata is present in the environment and may have a reservoir in wildlife populations in north-eastern NSW. Further investigation is required to better understand the occurrence of Salmonella in wildlife groups and to identify possible transmission pathways for human infections.

In 1978, 22 staff members of the National Institute of Virology, Pune, India, were given two doses of human diploid cell antirabies vaccine (HDCV) for primary pre-exposure prophylactic immunization; the interval between the two doses being approximately 4 weeks. Eighteen of these 22 vaccinees were given a booster dose 1 year later. All 18 vaccinees developed protective levels of antibody; most of them had antibody levels exceeding 10 IU/ml.

In 1984, 5 years after the booster dose, 11 (79·0%) of 14 vaccinees tested still possessed neutralizing antibody levels ranging from 0·5 IU/ml to 10 IU/ml. Fourteen days after the administration of a booster dose, the antibody levels ranged from 10 to ≥ 100 IU/ml for all except one vaccinee (5·2 IU/ml). These findings demonstrate that the majority of vaccinees retained detectable neutralizing antibody after pre-exposure prophylaxis for as long as 5 years and that a single booster dose thereafter evoked a good antibody response.

Toxoplasmosis caused by the protozoan parasite Toxoplasma gondii occurs worldwide. Infections range from asymptomatic to life-threatening. T. gondii infection is acquired either via bradyzoites in meat or via oocysts in the environment, but the relative importance of these path ways and the different sources remains unclear. In this study, possible risk factors for toxoplasmosis in the Netherlands were investigated. A case–control study was conducted including persons with recent infection and individuals with a negative test result for IgM and IgG for T. gondii between July 2016 and April 2021. A total of 48 cases and 50 controls completed the questionnaire. Food history and environmental exposure were compared using logistic regression. Consumption of different meats was found to be associated with recent infection. In the multivariable model, adjusted for age, gender, and pregnancy, consumption of large game meat (adjusted odds ratio (aOR) 8.2, 95% confidence interval 1.6–41.9) and sometimes (aOR 4.1, 1.1–15.3) or never (aOR 15.9, 2.2–115.5) washing hands before food preparation remained. These results emphasize the value of the advice to be careful with the consumption of raw and undercooked meat. Good hand hygiene could also be promoted in the prevention of T. gondii infection.

TLR3 and IL-10 play a crucial role in antiviral defence. However, there is a controversy between TLR3 rs3775291 and IL-10 rs1800871 polymorphisms and the risk of hepatitis B virus (HBV) infection. The purpose of this study is to explore the relationship between the two single nucleotide mutations and the risk of HBV infection by meta-analysis. Medline, EMBASE, Web of Science, CNKI, China Wanfang database were searched for the case-control studies on the relationship between TLR3 rs3775291 and IL-10 rs1800871 polymorphism and susceptibility to HBV, updated to June 2020. The data were analysed by Stata 15.0 software. A total of 22 articles were included. The results showed that in the analysis of IL10 rs1800871 polymorphism and the risk of HBV infection, the pooled OR was 1.21 (95% CI 1.06–1.37), 1.28 (95% CI 1.04–1.56) and 1.20 (95% CI 1.06–1.37) and 1.40 (95% CI 1.07–1.83) in the allele model (C vs. T), dominant model (CC+CT vs. TT), recessive model (CC vs. CT+TT) and homozygous model (CC vs. TT), respectively. There was no statistical significance in the heterozygote model. A subgroup analysis of the Asian population showed similar results. The analysis of TLR3 rs3775291 polymorphism and the risk of HBV showed that in the allele model (T vs. C), the pooled OR was 1.30 (95% CI 1.05–1.61). Except for the recessive model, no significances were found in other genetic models. In conclusion, TLR3 rs3775291 and IL-10 rs1800871 polymorphisms are associated with the risk of HBV. Allele C and genotype CC at IL10 rs1800871 loci, as well as allele T and genotype TT at TLR rs3775291 loci, may increase susceptibility to Hepatitis B infection.

A community outbreak of legionellosis occurred in Barrow-in-Furness, Cumbria, during July and August 2002. A descriptive study and active case-finding were instigated and all known wet cooling systems and other potential sources were investigated. Genotypic and phenotypic analysis, and amplified fragment length polymorphism of clinical human and environmental isolates confirmed the air-conditioning unit of a council-owned arts and leisure centre to be the source of infection. Subsequent sequence-based typing confirmed this link. One hundred and seventy-nine cases, including seven deaths [case fatality rate (CFR) 3·9%] were attributed to the outbreak. Timely recognition and management of the incident very likely led to the low CFR compared to other outbreaks. The outbreak highlights the responsibility associated with managing an aerosol-producing system, with the potential to expose and infect a large proportion of the local population and the consequent legal ramifications and human cost.

The following paper is based on the results obtained by cultivating and experimenting with strains of Meningococcus from 45 different cases of Meningitis. Twenty-five of these occurred in Epidemic areas and 20 were Sporadic cases occurring in London. The Epidemic strains are referred to throughout this paper as E. 1, E. 2, E. 3, etc., and the London strains (Sporadic) as L. 1, L. 2, L. 3, etc. For most of the Epidemic strains I am indebted to Dr M. Macdonald of the Lightburn Hospital, Shettlestone, and to Dr C. B. Ker of the Fever Hospital, Edinburgh. Also I have used strains sent to the Lister Institute by Professor Symmers from Belfast and by Dr Buchanan from Glasgow.

We studied 7 patients with nosocomial Legionnaires' disease to determine the relationship between isolates of Legionella pneumophila recovered from potable water and those recovered from patients. Potable water was cultured from all rooms in which patients had stayed prior to the diagnosis of Legionnaires' disease. The 38 isolates of L. pneumophila (31 environmental, 7 patient) were resolved into 9 distinct patterns by pulse-field gel electrophoresis (PFGE), 3 by plasmid content and 2 each with monoclonal antibodies and conventional agarose gel electrophoresis of small fragments of DNA.

Using PFGE it was determined that 4 of the 7 patients were infected with L. pneumophila identical to an isolate recovered from the potable water supply in one of the rooms each had occupied prior to the diagnosis of Legionnaires' disease. Patients had resided in a mean of 3·57 rooms before a diagnosis of nosocomial Legionnaires' disease. We conclude that in the setting of contaminated potable water and nosocomial Legionnaires' disease water from all the rooms which the patient has occupied prior to this diagnosis should be cultured. PFGE of large DNA fragments discriminated best among the isolates of L. pneumophila.

We report the clinical, microbiological, and epidemiological features of an emerging serotype, Shigella boydii 20. We interviewed patients about symptoms, and history of travel and visitors during the week before illness onset. Seventy-five per cent of the 56 patients were Hispanic. During the week before illness onset, 18 (32%) travelled abroad; 17 (94%) had visited Mexico. Eight (21%) out of 38 who had not travelled had foreign visitors. There were eight closely related patterns by PFGE with XbaI. S. boydii 20 may be related to travel to Mexico and Hispanic ethnicity. Prompt epidemiological investigation of clusters of S. boydii 20 infection may help identify specific vehicles and risk factors for infection.

We performed a systematic review to estimate the effectiveness of vaccination, in addition to chemoprophylaxis, in preventing meningococcal disease among household contacts. Medline, EMBASE, EMGM, and EUIBIS were used for data collection. Studies reporting on at least 100 primary cases and on subsequent cases in household settings with follow-up of more than 2 weeks after onset of disease in the primary case were reviewed. A meta-analysis was used to calculate the average attack rate in household contacts given chemoprophylaxis 14–365 days after onset of disease in the primary case. In total, 652 studies were identified, five studies and one unpublished report met the inclusion criteria. The weighted average attack rate was 1·1/1000 household contacts (95% CI 0·7–1·7). This review supports vaccination of household contacts in addition to chemoprophylaxis to reduce the risk of meningococcal disease among household contacts of a case caused by a vaccine-preventable serogroup.

Suppose that λ is the average density per unit volume in a suspension of infective particles such as virus particles. To estimate λ the usual method is to make up a series of inocula of various dilutions containing expected numbers of particles …λi−1, λi, λi+1,… which are known multiples of λ. Each of these is then tested by inoculation in a host such as an egg. We consider only the case where the dilution series is twofold (λi=λ2i, say) and the same number of eggs, N, is tested at each dilution. Then if we are sure that an egg is infected if and only if the inoculum contains at least one infective particle, the probability that the egg remains sterile is Pi=exp {− λ2i}. If each particle is not certainly infective but has a probability p of infecting the egg, the probability of sterility of an egg chosen at random is exp {− λp2i} provided that p does not vary from egg to egg. It is then only possible to estimate λp from the results.

Contacts of leprosy patients have a higher risk of developing clinical leprosy. Being a contact is defined socially, but with the introduction of geographical information systems (GIS) in infectious disease epidemiology, it is necessary to relate spatial distance to social distance. We measured the distances between patients and their socially defined contacts in northwest Bangladesh. Contact categories differ in mean distance to the index patients. Sixty-seven per cent of the high-risk contacts lived within 10 metres (m), while all low-risk contacts lived >10 m from the index patient. Classification based on intervals of spatial distance creates categories that contain contacts of different socially defined categories, illustrated by a category of people living between 10 m and 20 m consisting of 47% of high-risk contacts and 52% low-risk contacts. Classification of contacts based on the spatial distance, as performed with GIS techniques, produces other groups than with social definitions.

Q fever has been associated with exposure to domesticated livestock and the agricultural industry. However large population-based studies examining the relationship are lacking. This report sought to describe the association between Coxiella burnetii infection and participation in agricultural work in the 2003–2004 National Health and Nutrition Examination Survey. Adjusted logistic regression analysis showed that agricultural workers were six times more likely to have antibody evidence of C. burnetii infection than those employed in other occupations (odds ratio 6·5, 95% confidence interval 1·7–25·3). These findings suggest that agricultural workers may experience greater C. burnetii infection and emphasize an important need for more detailed study of people engaged in this work.

Encephalitis lethargica (EL) was first reported in 1917 in central Europe. It became epidemic in the winter of 1918/1919 concurrently with the pandemic of influenza, and by then had reached Russia and North America. It spread throughout the world in epidemic form, mainly in the succeeding winters, up to 1927. By then about 65 000 cases had been reported, although the true number worldwide can only be guessed at. EL mortality was about 30% in the acute stage, and similar during recurrences. Half of the survivors had persistent or recurrent neuro-psychiatric illness, with Parkinsonism a frequent end stage. Most contemporary observers attributed EL to a virus and some believed it was specifically a post-influenzal complication. The epidemiology of EL mostly points to an infective cause, e.g. a seasonal respiratory or gastrointestinal virus with infrequent encephalitic expression but the ability to persist, flare and progressively damage the brain. However, any link with the influenza virus strain of 1918/1919 remains hypothetical. The aetiological theories that have been applied to EL are reviewed and the question is raised whether broader laboratory investigation might now reveal a continuing low endemicity of EL and identify its cause.

1. Fletcher and Lesslar's observations on two serological types of tropical typhus have been fully confirmed.

2. The antigenic relationship between the indologenic B. proteus X 19 and the non-indologenic Kingsbury strain is of the same order as that obtaining between the X 19 and X 2 types of B. proteus X.

3. The Kingsbury strain is an antigenic variant derived from the original X 19 culture and represents another serological type of B. proteus X. The symbol XK is suggested for this type.

4. Sera from cases of classical European typhus and of endemic typhus of the United States of America and of Australia have been tested for the occurrence of main and group O agglutinins for the known types of B. proteus X.

5. H agglutination as source of error in the diagnosis of typhus cases is illustrated by some examples.

6. Sera from cases of tsutsugamushi from Sumatra and Japan react with type XK like the Malayan cases of this disease described by Fletcher and co-workers.

7. This latter reaction is of the order of group O agglutination. It is suggested that antigenically the virus of tsutsugamushi corresponds to another serological type of B. proteus X which is yet unknown.

8. The data published on the serum reactions in Rocky Mountain spotted fever and in the “fièvre exanthématique” of Marseilles are analysed. It is suggested that these two diseases represent further serological varieties of typhus.

9. The significance hitherto attached to negative agglutination tests with B. proteus X and to negative cross-immunity tests obtained with some typhuslike diseases requires revision in the light of recent observations.