Low agglutinin titres to pertussis suspensions were found in 99% of sera from a group comprising healthy adults and non-vaccinated, non-infected infants of 1–6 months of age. These are attributable to agglutinins to heat-stable antigens and/or heat labile agglutinogen 1, and cross-absorption tests must be done on the sera in order to distinguish between the two. Agglutinins to agglutinogens 2 and 3 were found in only about 20% of adult sera. Bactericidal antibody was low in titre or absent in all sera from non-exposed individuals.

Raised bactericidal antibody titres and the presence of agglutinins 2 and 3 were attributed to exposure to Bordetella pertussis antigens, either as vaccine or as infection. The variation, amongst both vaccinated and infected children, was very great. A vaccinated child who became ill responded to the infection in much the same way as a non-vaccinated child. We were unable to relate the immunity of the child to the titres either of agglutinins or of the bactericidal antibody.

The protective ability of sera from vaccinated or infected children measured in mice against small, lethal brain infections was also unrelated to the state of immunity in the children, but this protective ability was correlated with the complement-mediated bactericidal antibody titres of the sera.

The distribution of agglutinins, bactericidal antibody, and anti-haemagglutinin in serum IgG and IgM was different in vaccinated and infected children.

Twenty-two strains of enteroaggregative Escherichia coli (EAggEC), isolated from four outbreaks of diarrhoeal disease in England, were examined for a range of phenotypic attributes including the ability to produce fimbriae, haemolysins and siderophores, and cell-surface properties such as surface charge and hydrophobicity. Strains of EAggEC isolated from two of these outbreaks belonged to a diverse range of serotypes and were heterogeneous in phenotype. Strains of EAggEC isolated from the other two outbreaks belonged predominantly to serotypes O86[ratio ]H34 and O98[ratio ]H-, respectively. Only two strains expressed fimbriae and two strains produced an 18 kDa membrane associated protein (MAP), suggesting that EAggEC express a range of adhesion mechanisms to produce the cell arrangement recognized as the ‘stacked brick’ formation. The possible explanation for the diversity of EAggEC serotypes is discussed.

The incidence of Vibro parahaemolyticus in products of the Malaysian export shrimp processing industry was investigated through the stages from the catch to that of the cooked, peeled and frozen product. The organism was commonly found in freshly caught and landed shrimp, and could be detected by enrichment culture at all stages of processing. The numbers of V. parahaemolyticus in shrimp varied from nil to 4 × 104, and 19 of the 50 serotypes in the current antigenic scheme were found, O1-K38 and O1-K32 occurring most often. All the isolates were Kanagawanegative; one strain was a sucrose-positive variant. The study indicated that specifications of 102 g−1 for V. parahaemolyticus in raw tropical shelfish are too stringent but that the Malaysian shrimp industry should be able to meet this requirement for cooked shrimp.

No accepted or acceptable explanation of the phenomenon has yet been put forward. It has been suggested by the various authors and particularly by Fridericia et al. (1927) that bacterial synthesis of vitamin B in the intestine of the rat may be the explanation of the condition. Schieblich & Rodenkirchen (1929) have described a “vibrio-like” organism which they claim to be responsible for refection, but this finding has so far not been confirmed. In a recent dissertation on refection Nathan (1935) believes that the explanation is coupled with the nature of the starch in the diet rather than with an infection with a specific type of organism.

The conjunctival sacs of 100 healthy adult ewes and 20 lambs and 76 adult ewes affected by ovine keratoconjunctivitis (OKC) were examined microbiologically. Branhamella ovis was the only organism regularly isolated from healthy ewes and lambs. Mycoplasma conjunctivae was isolated from the conjunctival sac of nine ewes but its occurrence was not associated with clinical signs of ovine keratoconjunctivitis. Mycoplasma conjunctivae and Branhamella ovis were isolated significantly more often from eyes affected by OKC than from unaffected eyes.

Different genetic typing procedures were applied in an epidemiological study of Salmonella serotype Ohio. Isolates that generated identical DNA fingerprints (HincII ribotypes, ERIC and RAPD profiles) were clustered into the same lineage, and the addition of data from plasmid, integron and resistance profiles was used to differentiate types. Results led to the determination of the endemic and the emergent epidemic types at specific times, and to ascertain the clinical and epidemiological impact of each type. In the series analysed (47 clinical isolates and 3 non-clinical isolates) 11 lineages and 32 types were found. Two lineages were considered prevalent and endemic, and during an epidemiological alert (Spain, 1998) a re-emergence and spread of organisms mainly from the most frequent lineage had occurred. The combination of H-ribotype with ERIC profile, as primary markers, and resistance profile with plasmid profile, as secondary markers, was shown to be the most useful tool to trace epidemiologically Ohio.

The present study examined the effect of hepatitis B virus (HBV) and alcohol intake, and the role of hepatitis delta virus (HDV) and hepatitis C virus (HCV) in the aetiology of chronic liver disease in Albania. A total of 106 cases of liver cirrhosis or chronic hepatitis were compared to 195 control patients without these or other liver diseases. Adjusted odds ratios were 52·7 (95% CI 22·7–122) for HBV surface antigen, 26·9 (95% CI 4·9–147) for anti-HCV, 26·2 (95% CI 3·1–221) for anti-HDV, 2.4 (95% CI 1·3–4·4) for lifetime alcohol intake and 2·3 (95% CI 1–5·5) for duration of alcohol intake. Although not significant, an interaction was suggested between HBsAg and anti-HCV and between HBsAg and alcohol intake. Our study underlines the role of hepatitis viruses in the development of chronic liver diseases. Additionally, it suggests that heavy alcohol intake may magnify the effect of HBV on these diseases. HBV vaccination and alcohol abstention appear to be important strategies to reduce the risk of liver cirrhosis and chronic hepatitis in Albania.

The anticoagulant rodenticide flocoumafen was tested against warfarin-resistant Norway rats (Rattus norvegicus Berk.) infesting farm buildings. Complete control was obtained in 10–21 days (mean 14·2 days) in six treatments in which baits poisoned with 0·005% flocoumafen were maintained, in surplus, until rats ceased to feed from them. A further six treatments, in which the application of poisoned bait was restricted to periodic placements of 50 g, were also completely successful in 15–30 days (mean 21·0 days). Less poisoned bait was used in the restricted flocoumafen treatments than in the unrestricted treatments but the time taken to control the rat infestations was significantly longer.

For decades, vaccination with the 23-valent polysaccharide pneumococcal vaccine (PPV23) has been available for risk groups aged ⩾2 years to prevent invasive pneumococcal disease (IPD). Recently, a 13-valent pneumococcal conjugated vaccine (PCV13) has been licensed for use in all age groups. PCV13 may induce better protection than PPV23 because of different immunogenic properties. This called for a revision of vaccine recommendations for risk groups. We therefore reviewed literature on risk groups for IPD, and effectiveness and safety of pneumococcal vaccines and supplemented that with information from public health institutes, expert consultations and data on IPD epidemiology. We included 187 articles. We discuss the implications of the heterogenic vulnerability for IPD within and between risk groups, large indirect effects of childhood immunization, and limited knowledge on additional clinical benefits of PCV13 in combination with PPV23 for the Norwegian recommendations. These are now step-wise and consider the need for vaccination, choice of pneumococcal vaccines, and re-vaccination interval by risk group.

In three successive years, we visited petting farms (n=132), care farms (n=91), and farmyard campsites (n=84), respectively, and completed a standard questionnaire with the objective of determining the hygienic status of these farms and describing hygiene measures implemented to reduce the risk of transmission of zoonotic agents from the animals to humans. For at least 85% of the farms, the overall impression of hygiene was recorded as good. However, more attention must be paid to: informing visitors on hygiene and handwashing, provision of handwashing facilities, and a footwear cleaning facility. Examination of samples of freshly voided faeces resulted in the detection of Shiga toxin-producing Escherichia coli O157 and/or Salmonella spp. and/or Campylobacter spp. at almost two-thirds (64·9%) of the petting farms, and around half of the care farms (56·0%) and farmyard campsites (45·2%). These data reinforce the need for control measures for both public and private farms to reduce human exposure to livestock faeces and thus the risk of transmission of zoonotic diseases. Public awareness of the risk associated with handling animals or faecal material should be increased.

There are so many unexplained problems in connection with food poisoning that it is still of importance to study in detail and with care every outbreak. I have perused the records of several hundred food poisoning outbreaks, published and unpublished, and the prevailing impression left is one of regret that so many opportunities of clearing up obscurities and elucidating channels of infection have been lost by omission to push investigations home. The outbreak recorded here is in pleasant contrast and worthy of detailed study. It is noteworthy for two features. The bacillus isolated was not only isolated from the incriminated food but it was recovered from water from a tank in the slaughter-house, a rather unusual feature. This suggests a method of infection which has not hitherto been reported.

Toxoplasma gondii is a globally distributed parasitic protozoan that infects most warm-blooded animals. We incorporated a bead coupled with recombinant SAG2A protein into our Neglected Tropical Disease (NTD) multiplex bead assay (MBA) panel and used it to determine Toxoplasma infection rates in two studies in Haiti. In a longitudinal cohort study of children aged 0–11 years, the infection rate varied with age reaching a maximum of 0·131 infections/year in children aged 3 years [95% confidence interval (CI) 0·065–0·204]. The median time to seroconversion was estimated to be 9·7 years (95% CI 7·6–∞). In a cross-sectional, community-wide survey of residents of all ages, we determined an overall seroprevalence of 28·2%. The seroprevalence age curve from the cross-sectional study also suggested that the force of infection varied with age and peaked at 0·057 infections/year (95% CI 0·033–0·080) at age 2·6 years. Integration of the Toxoplasma MBA into NTD surveys may allow for better estimates of the potential burden of congenital toxoplasmosis in underserved regions.

We analysed the reported duration of incubation and symptomatic periods of norovirus for a dataset of 1022 outbreaks, 64 of which reported data on the average incubation period and 87 on the average symptomatic period. We found the mean and median incubation periods for norovirus to be 32·8 [95% confidence interval (CI) 30·9–34·6] hours and 33·5 (95% CI 32·0–34·0) hours, respectively. For the symptomatic period we found the mean and median to be 44·2 (95% CI 38·9–50·7) hours and 43·0 (95% CI 36·0–48·0) hours, respectively. We further investigated how these average periods were associated with several reported host, agent and environmental characteristics. We did not find any strong, biologically meaningful associations between the duration of incubation or symptomatic periods and the reported host, pathogen and environmental characteristics. Overall, we found that the distributions of incubation and symptomatic periods for norovirus infections are fairly constant and showed little differences with regard to the host, pathogen and environmental characteristics we analysed.

1. A simply made selective tellurite medium for the isolation of Corynebacterium diphtheriae and the identification of its types has been described.

2. The ingredients of this medium are easily obtained and can be stored for any length of time making the medium readily available at short notice.

3. Large or small quantities of the medium can be made with equal facility.

4. When grown on the medium, C. diphtheriae will produce colonies characteristic of its type, be it gravis, mitis or intermediate.

5. The appearance of the colonies has been described and has been shown to resemble closely, in the case of each type respectively, the appearances described by the Leeds workers (Anderson et al. (1931)) on their medium in the original papers.

6. The possibilities of the use of this medium for diagnostic routine swab examinations have been briefly referred to.

Although previous studies have reported Leptospira carriage in kidneys and urine of cats, the role of these animals in leptospirosis epidemiology remains poorly understood. Using molecular methods, we investigated Leptospira renal carriage in 172 feral cats from Reunion Island, an oceanic geographically isolated island located in the South West Indian Ocean. Only one out of the 172 analysed specimens tested positive for Leptospira DNA through quantitative real-time polymerase chain reaction. Using this positive sample, we could obtain sequences at three Leptospira loci (rrs2, lipL32 and lipL41) allowing to report for the first time Leptospira borgpetersenii naturally infecting cats. Comparisons with bacterial sequences from both acute human cases and animal reservoirs revealed similarities with Leptospira sequences previously reported on Reunion Island. However, the low prevalence (0.6%) reported herein does not support any major role of feral cats in leptospirosis epidemiology on Reunion Island, contrasting with results recently reported on another Indian Ocean Island, Christmas Island. The significance of these discrepancies is discussed.

A passive protection test with brucella antibodies, based on the spleen counts technique, has been described. This test has been found more sensitive than that based on lethal challenge.

Normal human sera have been shown to possess marked protecting power.

Protective activity of human sera was considerably increased following vaccination with living streptomycin-dependent brucellae, or after natural disease.

The bearing of these findings on several brucellosis problems has been briefly discussed.

The author wishes to express his thanks to Prof. A. L. Olitzki for constant advice and encouragement; to Dr H. V. Muhsam, Department of Statistics, the Hebrew University, for generous help in the statistical analysis; and to Miss R. Avraam for technical assistance.

We investigated the incidence of cases of nosocomial pathogens and risk factors in an intensive treatment unit ward to determine if the number of cases is dependent on location of patients and the colonization/infection history of the ward. A clustering approach method was developed to investigate the patterns of spread of cases through time for five microorganisms [methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter spp., Klebsiella spp., Candida spp., and Pseudomonas aeruginosa] using hospital microbiological monitoring data and ward records of patient-bed use. Cases of colonization/infection by MRSA, Candida and Pseudomonas were clustered in beds and through time while cases of Klebsiella and Acinetobacter were not. We used structural equation modelling to analyse interacting risk factors and the potential pathways of transmission in the ward. Prior nurse contact with colonized/infected patients, mediated by the number of patient-bed movements, were important predictors for all cases, except for those of Pseudomonas. General health and invasive surgery were significant predictors of cases of Candida and Klebsiella. We suggest that isolation and bed movement as a strategy to manage MRSA infections is likely to impact upon the incidence of cases of other opportunist pathogens.

The study aim was to examine the incidence and risk factors of respiratory syncytial virus (RSV) bronchiolitis hospitalisations and disease severity among infants. We compared demographic and health characteristics of children aged 0–23 hospitalised for RSV bronchiolitis (cases, n = 1227) during 2008–2018 and control children (n = 554) of the same age admitted for non-respiratory disease. RSV antigen was detected in nasal swabs by immunochromatography. Multiple logistic regression models were applied. The average annual incidence of hospitalisation for RSV bronchiolitis was 12.6 per 1000 and 1.7 per 1000 (P < 0.001) among infants and toddlers, respectively, with winter seasonality (November–March). The risk of hospitalisation for RSV bronchiolitis increased among children aged 0–5 months (OR 7.66; 95% CI 5.61–10.45) and 6–11 months (OR 12.88, 95% CI 8.48–19.55), compared to those aged 12–23 months. Additional risk factors were living in low vs. higher socio-economic status towns (OR 1.49; 95% CI 1.14–1.95), having chronic medical conditions (OR 2.75; 95% CI 1.61–4.70), birth month (October–January vs. June–September) (OR 2.19; 95% CI 1.60–2.99) and history of stay in neonatal intensive care unit at birth (OR 2.37; 95% CI 1.27–4.41). Male children and those who had pneumonia were more likely to have severe RSV bronchiolitis. In conclusion, the burden of hospitalisations for RSV bronchiolitis is high, especially in young infants. Effective preventive measures such as RSV active vaccines can reduce the risk of hospitalisations for RSV bronchiolitis among these vulnerable groups.

Few studies have used genomic epidemiology to understand tuberculosis (TB) transmission in rural and remote settings – regions often unique in history, geography and demographics. To improve our understanding of TB transmission dynamics in Yukon Territory (YT), a circumpolar Canadian territory, we conducted a retrospective analysis in which we combined epidemiological data collected through routine contact investigations with clinical and laboratory results. Mycobacterium tuberculosis isolates from all culture-confirmed TB cases in YT (2005–2014) were genotyped using 24-locus Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats (MIRU-VNTR) and compared to each other and to those from the neighbouring province of British Columbia (BC). Whole genome sequencing (WGS) of genotypically clustered isolates revealed three sustained transmission networks within YT, two of which also involved BC isolates. While each network had distinct characteristics, all had at least one individual acting as the probable source of three or more culture-positive cases. Overall, WGS revealed that TB transmission dynamics in YT are distinct from patterns of spread in other, more remote Northern Canadian regions, and that the combination of WGS and epidemiological data can provide actionable information to local public health teams.

This study investigated 21 foodborne type-E botulism outbreaks, without antitoxin administration, from 1951 to 1965 in Hokkaido, Japan, to characterize the descriptive epidemiology and evaluate the relationship between case fatality and incubation period. The median (25–75% quartile) attack rate and case fatality, which were evaluated by outbreak, were 58·3% (38·0–73·2) and 25·7% (0·1–50·0) respectively. Individual records of 64 diagnoses, including 31 deaths, were also examined using logistic regression analysis, revealing that a shorter incubation period is likely to result in a significantly higher risk of death (P=0·01). The observed case fatality was more than 50% for those who developed symptoms within the first 18 h after exposure, possibly reflecting underlying dose-dependent mechanisms. In the event of intentional contamination of food with botulinum toxin, rapidly determining the incubation periods may be critical for guiding public health response efforts.