A two-minute strep A direct swab test (SADST) was used to detect the presence of Lancefield group A streptococci (GAS) from the throats of 207 patients with pharyngitis at a primary-care clinic. The results were compared with a standard culture method. Fifty-one specimens were positive and 156 specimens were negative for GAS by culture. The SADST had a sensitivity of 96% (49 of 51) and specificity of 98·7% (154 of 156). The predictive values of a positive and negative SADST, for GAS, were 96% and 98·7 % respectively. The SADST showed negative reactions with five specimens containing beta-haemotytic streptococci other than GAS and 34 known stock cultures other than GAS. Our results indicate that SADST is a rapid, simple, convenient and reliable test to use for diagnosis of GAS pharyngitis at primary care clinics, physicians' offices and clinical laboratories.

Nasal carriage of Staphylococcus aureus was studied in a cohort of infants born to the residents of two towns in South Wales. The children were followed up to the age of 5 years, nasal swabs being taken annually after a more detailed survey during the first year. The carriage-rate of S. aureus reached a minimum of 10–15% at one year and then rose steadily to 41% at five years. From the age of two years about 90% of the organisms isolated were resistant to penicillin. There was a marked tendency for children to carry the same strains from year to year, but carriage during the first year of life did not predict carriage at the age of five.

Dengue virus type 3 genotype III (DENV-3/III) is widely distributed in most dengue-endemic regions. It emerged in Malaysia in 2008 and autochthonously spread in the midst of endemic DENV-3/I circulation. The spread, however, was limited and the virus did not cause any major outbreak. Spatiotemporal distribution study of DENV-3 over the period between 2005 and 2011 revealed that dengue cases involving DENV-3/III occurred mostly in areas without pre-existing circulating DENV-3. Neutralisation assays performed using sera of patients with the respective infection showed that the DENV-3/III viruses can be effectively neutralised by sera of patients with DENV-3 infection (50% foci reduction neutralisation titres (FRNT50) > 1300). Sera of patients with DENV-1 infection (FRNT50 ⩾ 190), but not sera of patients with DENV-2 infection (FRNT50 ⩽ 50), were also able to neutralise the virus. These findings highlight the possibility that the pre-existing homotypic DENV-3 and the cross-reacting heterotypic DENV-1 antibody responses could play a role in mitigating a major outbreak involving DENV-3/III in the Klang Valley, Malaysia.

We simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3–47·7] and 44% (95% CI 36·4–51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3–49·0) and 36% (95% CI 27·9–44·0), respectively. Simulation of risk may be useful as a tool to classify local and regional hospitals according to their risk of nosocomial TB transmission, and to facilitate the design of hospital infection control plans.

The object of the inquiry reported upon in this paper was to determine whether there was any measurable association between the development of intelligence and the incidence of disease in school children.

A study was made of the available statistical data bearing on the epidemiology of typhoid in Palestine. It apears from this analysis that:

1. The typhiod epidemicity is not due to a single source such as contaminated water or food. The seasonal prevalence of the disease corresponds with the normal seasonal incidence of typhiod, and is, therefore, in the nature of a contact infection.

2. There is no striking difference in age, sex or race susceptibility. In Tel Aviv the age group 5–14 shows a lower incidence than the corresponding age group in Jerusalem or the higher age group 15–29 in Jerusalem and Tel Aviv. There is, however, no difference in susceptibility between the age group 15–29 in Jerusalem and that in Tel Aviv.

3. From a graphic comparisos, the calculation of the coefficient of correlation of the limited experience (six years), and a comparison of the prevalence of the disease in the immigrant and indigenous population, there appears to be a significant correlation between the net population increment and epidemicity. These results, if confirmed by a longer experience, are in accord with those obtained in the remarkable mice experiments conducted by the English and American investigators.

4. Although, at the beginning, the morbidity and mortality is higher in the immigrant group, there is an evident tendency at equalisation, and in the second year the incidence in the indigenous population is the same as that among the immigrants.

5. The above results indicate the path of control: (a) every immigrant, particularly those between the ages 5–29, should be properly vaccinated against typhoid. By raising the resistance of the new population, the possibility of epidemics among them, and consequently later among the resident population, will be averted; (b) the reduction of endemic typhoid can be brought about by reducing the dosage of the infectious microbes. This can only be brought about by concentration of effort on the early detection and isolation of cases and the vaccination of all contacts. These two measures would seem to offer a prompt and relatively simple solution to the typhoid problem in Palestine.

In terms of the rate of positive diagnoses the indirect fluorescent antibody (FA) test was rather more effective than iodine for demonstrating trachoma (TRIC) inclusions in conjunctival scrapings, but the degree of advantage was not statistically significant. In duplicate scrapings stained at random by one or the other method, FA staining yielded the higher inclusion count significantly more often than did iodine. Some inclusions that failed to stain with FA were found on subsequent staining with Giemsa. A method is described for improving the post-FA Giemsa staining of conjunctival smears stored at subzero temperatures. Given adequate facilities, the FA stain is preferable to iodine for demonstrating TRIC inclusions in the conjunctiva; but the iodine method, properly used, holds advantages for field use.

The results of immunization of 523 children from 9 months to over 5 years of age with two attenuated measles vaccines, ‘Denken’ and ‘Biken’, are described. The clinical reactions following vaccination with both vaccines were mild, but Denken vaccine produced more rashes than the Biken vaccine. The serological conversion was satisfactory for both vaccines but a higher titre of neutralizing and haemagglutination-inhibiting antibodies was found in children immunized with Denken vaccine. The incidence of severe reactions or complications was negligible in this trial. The immunity to diphtheria or tetanus was not altered by vaccination with live measles vaccine.

1. Rabbit cells show a marked variation in agglutination when reacting with apparently homologous iso-antisera.

2. This phenomenon has been investigated in two ways:

(a) Samples of apparently homologous antisera have been absorbed with (i) strongly agglutinating cells, (ii) poorly agglutinating cells. It was found that strongly agglutinating cells absorbed the antibody completely and rapidly from the serum, whilst poorly agglutinating cells, though they absorbed it completely, did so much more slowly. Also, when a serum which had been absorbed with poorly agglutinating cells until these no longer reacted with it was titrated against strongly agglutinating cells, these were still strongly agglutinated. This showed a source of serious error when investigating new sera by absorption techniques and when using weak antisera for grouping purposes.

(b) Poorly agglutinating cells were injected into rabbits, and the antisera so obtained were examined against strongly agglutinating cells and against the poorly agglutinating cell used as the antigen. The antibody response was poor; two out of eight rabbits developed an antibody, and strongly agglutinating cells reacted more strongly with these antisera than the poorly agglutinating cells which had been used as the antigen.

3. Three hypotheses for this variation in agglutination have been put forward and discussed:

(a) That the variation is due to cross reactions between numbers of closely related antigen-antibody systems. The results of the investigations 2 (a) and 2(b) suggest that this is unlikely.

(b) That the disposition of antigen sites on the surface of the red cell is a factor determining the agglutinability of the cell. It is considered that this might play a subsidiary role in the phenomenon as it is shown in the rabbit.

(c) That rabbit red cell agglutinability is mainly determined by the number of antigen sites on the cell available to the antibody. The experimental results can be explained on this hypothesis, and it is suggested that this may be the main factor accounting for the behaviour of rabbit red cells. It is pointed out that supporting evidence for this is afforded by measurements with radio iodinated antisera.

The purpose of this study was to investigate the microbiological quality of liver pâté. During 2012–13, a total of 870 samples, unrelated to the investigation of food-poisoning outbreaks, were collected either at retail (46%), catering (53%) or the point of manufacture (1%) and were tested using standard methods to detect Salmonella spp. or Campylobacter spp., and to enumerate for Listeria spp., including Listeria monocytogenes, Clostridium perfringens, coagulase-positive staphylococci including Staphylococcus aureus, Bacillus spp., including Bacillus cereus, Escherichia coli, Enterobacteriaceae, and aerobic colony counts (ACCs). Seventy-three percent of samples were of satisfactory microbiological quality, 18% were borderline and 9% unsatisfactory. Salmonella spp. or Campylobacter spp. was not recovered from any sample. The most common causes of unsatisfactory results were elevated ACCs (6% of the samples) and high Enterobacteriaceae counts (4% of samples). The remaining unsatisfactory results were due to elevated counts of: E. coli (three samples); B. cereus (one sample at 2·6 × 105 cfu/g); or L. monocytogenes (one sample at 2·9 × 103 cfu/g). Pâté from retail was less likely to be contaminated with L. monocytogenes than samples collected from catering and samples from supermarkets were of significantly better microbiological quality than those from catering establishments.

Sixty three samples of dairy creamery effluent were examined for the presence of mycobacteria. Thirty two strains were isolated from 27 samples. These were classified as follows: M. fortuitum (13), M. peregrinum (6), M. gordonae (5), M. marianum (scrofulaceum) (4), unidentified (4).

Ten strains, representative of the groups isolated, were tested for their effect on experimental animals. None were pathogenic for guinea pigs or mice but a number produced a minimal amount of skin sensitization in guinea pigs to avian and mammalian tuberculin.

During the winter of 1967–8 Sonne dysentery affected neighbouring North London primary schools. This was not simply due to cross-infection between the two schools, for two different, unusual strains of Sh. sonnei were distinguished. One was a novel kanamycin-resistant colicine type 7 strain, and as far as we know this was the first school outbreak due to such a strain to be documented. The other strain was kanamycin-sensitive and of colicine type 0 with a rare specific requirement for aspartic acid. There was some evidence to suggest that the kanamycin-resistant strain was more infective for adults and possibly more pathogenic than the kanamycin-sensitive.

Studies on the transfer of drug resistance and of colicinogeny revealed that the factor determining colicine type 7 was carried on a transmissible plasmid, a new observation. Various drug resistances were also transmissible experimentally, and some were spontaneously unstable. Non-transferable ampicillin-resistance in the colicine type 7 strain and aspartic acid dependence in the colicine type 0 strain enabled all but one of the isolates to be classified into two distinct lines. No common ancestor was found and it was concluded that although occurring together they must have arisen from separate sources.

In order to evaluate the role of the RAD51 G135C genetic polymorphism on the risk of gastric cancer induced by Helicobacter pylori infection, we determined allele frequency and genotype distribution of this polymorphism in Bhutan – a population documented with high prevalence of gastric cancer and extremely high prevalence of H. pylori infection. The status of RAD51 G135C was examined by restriction fragment length polymorphism analysis of PCR amplified fragments and sequencing. Histological scores were evaluated according to the updated Sydney system. G135C carriers showed significantly higher scores for intestinal metaplasia in the antrum than G135G carriers [mean (median) 0·33 (0) vs. 0·08 (0), P = 0·008]. Higher scores for intestinal metaplasia of G135C carriers compared to those of G135G carriers were also observed in H. pylori-positive patients [0·3 (0) vs. 0·1 (0), P = 0·002] and H. pylori-positive patients with gastritis [0·4 (0) vs. 0·1 (0), P = 0·002] but were not found in H. pylori-negative patients. Our findings revealed that a combination of H. pylori infection and RAD51 G135C genotype of the host showed an increasing score for intestinal metaplasia. Therefore, RAD51 G135C might be the important predictor for gastric cancer of H. pylori-infected patients.

Healthcare-associated infections in veterinary hospitals are commonly attributed to Salmonella enterica, particularly in large animal facilities, and are characteristically associated with widespread environmental contamination. The objective of this study was to investigate factors influencing the likelihood of identifying environmental contamination of a veterinary hospital with S. enterica, while exploring different analytic methods to model complex factors that may influence this ecology. Environmental surveillance samples were collected in a large veterinary hospital as part of a long-term infection control programme. Data were collected retrospectively from the electronic medical records database. Many easily measured variables were complex in nature (i.e., they represented variance that is unmeasured or unidentified as a specific factor) necessitating the use of alternative analytic methods (variable cluster and principal components analyses) to provide perspective regarding the complex data structure and latent factors that may be contributing to this ecology. Subsequently, multivariable logistic regression was performed using generalised estimating equations. Results suggest the probability of detecting Salmonella in the environment increased as demand on personnel increased (e.g., in a busy hospital). Veterinary personnel need to remain vigilant in implementing practices that we believe empirically will mitigate risk for widespread environmental contamination and sustained transmission among patients (i.e., rigorous hygiene for personnel and the environment).

Gas production by coliform organisms and Escherichia coli from lauryl tryptose lactose broth (LTLB) was compared with that from brilliant green (lactose) bile broth (BGB). These media were compared with lauryl tryptose mannitol broth (LTMB) with and without added tryptophan for both gas and indole production. At 37 °C, LTLB and BGB were both satisfactory for gas production, but at 44 °C, LTLB gave fewer false-negative results and was thus significantly less inhibitory than BGB. However when LTLB and LTMB were compared as single-tube confirmatory media, LTLB give a high proportion of false-negative reactions in the indole test at 44 °C. The substitution of mannitol for lactose and the addition of tryptophan yielded a satisfactory medium for both confirmation of gas production and the demonstration of indole at 44 °C.

Dengue virus, commonly transmitted by mosquitoes, causes a human disease of significant social impact and presents a serious public health problem in Brazil. This report describes the unusual emergence of DENV-4 in northern Brazil after a nearly 30-year-long absence. DENV-4 genotype I is of Asian origin and was identified in the serum of patients receiving treatment at a hospital serving the Salvador area (Brazilian state of Bahia). The identification of dengue virus serotypes through molecular and phylogenetic analysis is essential for predicting disease severity or fatal illness, principally in endemic countries such as Brazil.

The objective of the study was to assess whether genotypic characterization by means of DNA-fingerprinting pattern (DFP) and multilocus enzyme electrophoresis (MEE) profile as compared to phenotypic characterization would improve the differentiation of Neisseria meningitidis strains associated with outbreaks from strains associated with sporadic cases of meningococcal disease. In addition, the differentiation of serogroup C carrier strains from those associated with an outbreak of serogroup C meningococcal disease was investigated.

A total of 118 N. meningitidis strains were available for the study: 59 from patients involved in outbreaks of meningococcal disease (2 serogroup B and 2 serogroup C), 37 from patients considered to be sporadic cases and 22 serogroup C carrier strains.

Among the 59 strains from patients involved in outbreaks the 4 strains isolated from the patient registered as the first in each outbreak were designated the index strains. Among the remaining 55 outbreak strains 52 were either DFP-identical or DFP-indistinguishable when compared with the one relevant out of the 4 index strains. This was only the case for 17 of the 37 strains isolated from sporadic cases caused by the same serogroup of meningococci during the outbreak periods, and 5 of the 22 meningococcal strains isolated from healthy carriers. Among the 56 (52 + 4) DFP-identical or DFP-indistinguishable outbreak strains 5 different electrophoretic types were identified by MEE.

Among 59 assumed outbreak strains a total of 4 were identified as genotypically distinct. Among the 37 mainly DFP-indistinguishable or DFP-different strains from sporadic cases 17 different ETs were identified, and among the 22 mainly DFP-different carrier strains 13 different ETs were identified. Two strains among those selected from sporadic cases were identical to the outbreak strain. None of the local serogroup C carrier strains isolated during the outbreak of serogroup C disease were identical to the outbreak strain.

Both DNA-fingerprinting and MEE improved the differentiation of meningococci when compared with phenotypic characterization. The results indicate that tracing a virulent strain within an open group of contacts is irrelevant.

The objective of this study was to assess the use of statistical algorithms in identifying significant clusters of Salmonella spp. across different sectors of the food chain within an integrated surveillance programme. Three years of weekly Salmonella serotype data from farm animals, meat, and humans were used to create baseline models (first two years) and identify weeks with counts higher than expected using surveillance algorithms in the third (test) year. During the test year, an expert working group identified events of interest reviewing descriptive analyses of same data. The algorithms did not identify Salmonella events presenting as gradual increases or seasonal patterns as identified by the working group. However, the algorithms did identify clusters for further investigation, suggesting they could be a valuable complementary tool within an integrated surveillance system.

Although pneumonic plague is listed by the Centers of Disease Control in the leading ‘critical biological agents’, very few studies exist on this subject. In this study, a mathematical compartment model was used to describe the geographical and temporal spread of an epidemic of pneumonic plague following its use as a biological weapon. Univariate and multivariate analyses were performed in order to assess the key parameters for the control of an outbreak in France. If interventions were taken 10 days after an attack, a reference scenario of 1000 index cases in Paris would lead to 2500 deaths. The results of the study indicate that the rapidity of onset of interventions has the largest effect on the final size of the epidemic, followed by wearing masks, treating contacts preventively and quarantine. Limiting inter-regional mixing does little to reduce casualties, although it does confine them to a single region.

The goals of this article are: (i) to understand how individual characteristics affect the likelihood of patients defaulting their pulmonary tuberculosis (PTB) treatment regimens; (ii) to quantify the predictive capacity of these risk factors; and (iii) to quantify and map spatial variation in the risk of defaulting. We used logistic regression models and generalized additive models with a spatial component to determine the odds of default across continental Portugal. We focused on new PTB cases, diagnosed between 2000 and 2013, and included some individual information (sex, age, residence area, alcohol abuse, intravenous drug use, homelessness, HIV, imprisonment status). We found that the global default rate was 4·88%, higher in individuals with well-known risk profiles (males, immigrants, HIV positive, homeless, prisoners, alcohol and drug users). Of specific epidemiological interest was that our geographical analysis found that Portugal's main urban areas (the two biggest cities) and one tourist region have higher default rates compared to the rest of the country, after adjusting for the previously mentioneded risk factors. The challenge of treatment defaulting, either due to other individual non-measured characteristics, healthcare system failure or patient recalcitrance requires further analysis in the spatio-temporal domain. Our findings suggest the presence of significant within-country variation in the risk of defaulting that cannot be explained by these classical individual risk factors alone. The methods we advocate are simple to implement and could easily be applied to other diseases.