Three enzyme immunoassays were used for the serodiagnosis of Trypanosoma evansi in camels in the Sudan in order to evaluate their ability to discriminate between infected and non-infected animals. Two assays were used for the detection of trypanosomal antibodies, one using specific anti-camel IgG conjugate and another using a non-specific Protein A conjugate. The third assay detected the presence of trypanosomal antigens using anti-T. evansi antibodies in a double antibody sandwich assay. Inspection of the frequency distribution of assay results suggested that the ELISA for circulating trypanosomal antibodies using specific antisera and the ELISA for circulating antigens can distinguish between non-infected camels and infected camels exhibiting patent infections or not. The ELISA using Protein A conjugate to bind non-specifically to camel immunoglobulin did not appear to discriminate between infected and non-infected animals.

1. The effects of poison treatments on the rat populations of two sample districts of heavily infested sewers in a London borough were studied.

2. Each district had a maximum rat population represented by a census figure of about 10,000 g. wheat eaten per day, corresponding to at least 400 rats.

3. Poison treatments after prebaiting, at intervals of 6 months, reduced the rat population of each district to less than 10% of the maximum. A rapid restoration of the population followed, and the level reached in 6 months was near the maximum.

4. In both areas, direct poisoning with sodium monofluoroacetate ‘1080’ was as effective as a prebaiting treatment. Direct poisoning with zinc phosphide was relatively unsuccessful.

5. When both areas received double treatments, consisting of direct poisoning with sodium monofluoroacetate followed by a prebaiting treatment, the estimated population of one district was reduced to about 3% of the maximum. In the other area, rain made the second poisoning ineffective.

6. The rate at which the population was restored from the 3% level was even higher than the rates previously observed, and was probably too high to be accounted for solely by breeding. Evidently, invasion from the surface played a part.

7. No relationship could be established between the estimated sewer rat population densities within each district, and the known sites of surface infestation.

We are grateful to the Council and officers of the Borough in which the work was done, for unstinted help throughout the inquiry. We also owe thanks to H. V. Thompson for help in the early stages; to him and to Miss M. D. A. Lawrence for discussing the work during its progress; to Miss M. M. Spencer for help in the analysis of the records and in checking calculations; and to A. G. Jenson for mapping the districts and for drawing the figures.

We have used molecular techniques to characterize 51 group A streptococci from Scotland and 17 ‘serious disease’ isolates from other countries, in order to establish the clonal structure of invasive Streptococcus pyogenes strains circulating between 1986 and 1993. Strains were grouped by restriction endonuclease analysis, pulsed field gel electrophoresis and ribotyping patterns, and were examined for the presence of alleles of the speA gene by polymerase chain reaction and DNA sequence analysis. Serious and fatal infections in Scotland were caused by several clones. One clone (9 of 51 strains) was M type 1 and possessed the speA gene allele 2. This was the clone previously identified as causing severe infection in the USA. Another clone (5 of 51 strains) was M type 3 and had speA gene allele 3. In view of the clear association of more than one clone with severe, invasive and fatal infections, horizontal gene exchange between genotypes merits further investigation.

The introduction and rapid spread of West Nile virus (WNV) into new areas such as the American continent, associated also with the severity of the disease in humans and equids has increased concerns regarding the need to better prevent and control future WNV incursions. WNV outbreaks in equids usually occur under specific climatic and environmental conditions and, typically, before detection of WNV cases in humans. Targeting surveillance strategies in areas and time periods identified as suitable for WNV outbreaks in equids may act as an early-warning system to prevent disease in both equids and humans. This study used a GIS-based framework to identify suitable areas and time periods for WNV outbreak occurrence in one of the most important areas of equid production in Spain, i.e. Castile and Leon. Methods and results presented here may help to improve the early detection and control of future WNV outbreaks in Spain and other regions.

The objectives of this study were to determine the prevalence of scabies in an infested village; to educate the residents on self-treatment and prevention by the use of 5 % monosulfiram soap; to evaluate the short term effectiveness of this intervention by determining, 2 weeks later, the compliance to self-treatment and prevention; and to determine the prevalence rate on the second visit. In 59 households (96·7% of the village) containing 313 persons, an educational session was held and a leaflet distributed on the use and availability of the soap. Thirteen persons (4·2%) from eight households (13·6%) had scabies. After 2 weeks, 7 persons (2·2%) (2 persisting and 5 new cases) from 5 households (8·5%) were infested. Thus a cure rate of 85 % was obtained though the prevalence rate showed no statistically significant difference. Among the under 15 year olds, the numbers infected decreased from 10 to 3 while among the over 15 year olds, the numbers infected increased from 3 to 4, neither reading significance at the 5 % level.

1. Attention is called to the widespread dissatisfaction with the standard of reproducibility attained with the existing disinfectant tests.

2. It is suggested that this lack of reproducibility is inherent in any 100% mortality test.

3. The trend in all recent disinfectant developments appears to be towards greater specificity than was the case with the older products.

4. Where a comparison is being made to ascertain the true relative efficiency of two or more disinfectants, this possible specificity necessitates their examination under a wider range of conditions than has been catered for in the past.

5. A technique is suggested for use in those cases where a more limited examination will provide all the information that is required. It employs a simple culture medium, uses a measured quantity for the transfer from the medication tube, and makes use of a compensated photo-electric circuit to determine the amount of growth produced by the organisms which have survived the contact with the disinfectant.

I wish to acknowledge my grateful thanks to the directors of Messrs Cooper, McDougall and Robertson Ltd. for permission to publish this paper, and to my colleagues of the Cooper Technical Bureau for assistance in various directions.

The antimicrobial resistance of 809 Salmonella Typhimurium isolates collected from humans in Norway between 1975 and 1998 was studied. The material was subdivided into domestic and foreign isolates according to whether the patient had recently travelled abroad or not. In imported isolates the largest increase in resistance was in 1996 when 35% of the isolates were multi-resistant. The first multi-resistant isolate acquired in Norway appeared in 1994, but already in 1998 23% of the isolates domestically acquired were multi-resistant, and a majority were S. Typhimurium DT104. We found no ciprofloxacin resistance in domestically acquired isolates. Amplified fragment length polymorphism analysis was performed on selected multi-resistant isolates. The method discriminated well between different multi-resistant isolates, but not between DT104 isolates. Resistant and multi-resistant S. Typhimurium were until 1998 essentially recovered from patients who had travelled abroad, but multi-resistant isolates, mainly DT104, are now also being transmitted within the country.

The present study was undertaken to investigate the occurrence of antibiotic resistance in enteric flora in 64 children in rural Bangladesh over a 12-month period. The antibiotic resistance pattern of the isolates varied throughout the year and multiple resistance was highest during the post monsoon period. Seventythree percent of children had isolates resistant to more than three antibiotics throughout the year. Resistance to streptomycin was highest (78%), followed closely by ampicillin (72%). Of 82 multiply resistant isolates, plasmid DNA was demonstrated in 75%. Plasmid sizes ranged between 3·7 and 110 MDa, the commonest plasmids were of 70, 98 and 110 MDa. Complete or partial resistance was transferred by conjugation from 52% of the isolates, most frequently by single plasmids. The commonest plasmid incompatibility group was F11-A (46%) followed by incompatibility group P (22%). Plasmids of molecular weight 98 MDa most often hybridized with F11-A probes and those of 110 MDa with H11 probes. Plasmids from 10 transconjugants were digested with restriction enzymes and digest patterns demonstrated the presence of common plasmids. The findings show that there is a diverse, and mobile, genetic pool of resistance genes in this rural community. This genetic reservoir is potentially transferable to enteric pathogens, with major implications for public health and diarrhoeal disease control.

We investigated the epidemic pattern of chickenpox incidence among 47 prefectures in Japan. There were two peaks in chickenpox incidence in all prefectures. The first peaks appear at almost the same time in a year, while the second peaks occur at different times with relatively different types of size and shape. The feature of the second peak might characterize the epidemic pattern of chickenpox. We first introduced the second peak index, that is, the ratio of the difference between the incidence at the point of the second peak and the minimum incidence between the first and second peaks to the difference between the incidence at the point of the second peak and the minimum incidence in the year. There was a close correlation between the second peak index and the magnitude of variation in temperature within a year corresponding to the difference between the maximum and the minimum of the monthly mean of the highest daily temperature. This is the first article focusing on the close relationship between the second peak of epidemic pattern of chickenpox incidence and the variation of temperature within a year.

(1) Chickens fed on a 1/20th their body-weight daily of padi, cured or parboiled unpolished rice, or fresh (partly polished) rice, remain free from polyneuritis for at least 28 to 100 days.

(2) Chickens fed on the same ration of polished Siam rice develop symptoms of polyneuritis in from 20 to 70 days.

(3) When the polished rice is soaked in excess of water for 24 hours the birds succumb to polyneuritis in from 10 to 35 days; when the rice is soaked for 48 hours the disease appears still more readily, viz. in 15 days.

(4) Chickens fed on 1/20th their body-weight of parboiled rice which had been soaked for 24 hours also develop polyneuritis in from 13 to 39 days. This fact is of practical importance, as epidemics of beri-beri have been traced to the practice of soaking unpolished rice prior to cooking and discarding the water.

(5) Although birds fed on diets of polished rice, sago, or glucose develop polyneuritis, when fed on commercial starch they often fail to do so and merely lose considerably in weight. An explanation is offered.

(6) While fowls fed on 1/20th their body-weight of padi remain free from polyneuritis for at least 60 to 100 days, when this ration is supplemented by 1/6th the body-weight of washed unpolished rice or 1/10th of polished rice polyneuritis appears in from 20 to 30 days.

(7) On the other hand, chickens fed on rations varying from 1/5th to 1/30th of their body-weight of washed unpolished rice develop polyneuritis in about the same time, 10 to 20 days.

(8) On dietaries composed of rations of polished rice varying from 1/20th to 1/40th the body-weight and of yeast varying from 1/2500th to 1/3500th the body-weight pigeons and chickens do not develop polyneuritis until at least 32 to 100 days have elapsed, but when the carbohydrate ration is doubled by the addition of polished rice or sago the birds fall ill in from 13 to 46 days.

(9) Even when daily rations of polished rice as large as 1/10th the body-weight are fed to chickens together with varying amounts of yeast, 93 to 98 per cent, of the carbohydrate is digested and absorbed and the excreta contain no anti-neuritic substance. This shows that the rapid development of polyneuritis induced by feeding large rations of starch is not due to interference of undigested carbohydrate with the absorption of the active material.

(10) Intestinal bacteria, unlike yeast, contain little anti-neuritic substance.

The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management.

On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers.

Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria. The Naegleria isolates were identified as N. lovaniensis, a species commonly found in association with N. fowleri.

Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools.

Antisera against live cultures of 20 strains of Bacteroides fragilis produced in rabbits agglutinated homologous whole-cell as well as O-antigen suspensions with several cross-reactions. Pure specific antisera were produced by absorbing cross-reacting antigens. O-antisera reacted against O-antigens but failed to do so against most whole-cell suspensions, suggesting the presence of surface structures which might have blocked the reactions. The titres of the whole-cell antisera were not significantly higher than those of O-antisera, but the reactions were more definite and easier to read.

This system may prove useful in serological studies of B. fragilis.

The signs and symptoms exhibited by 29 patients with an acute illness in whom antibodies to hantavirus were detected are described. In the severe cases the most striking signs and symptoms were the persistence for 2 or 3 weeks of a severe sore throat with pyrexia that developed early in the illness, followed by swelling of the face, neck and extremities, with arthropathy and prolonged malaise that lasted for months. A macular erythematous rash, hepatomegaly with abnormal liver function tests, and a tendency to haemorrhage was a later feature of the severe cases. Mild cases presented with a variety of signs and symptoms that were very difficult to link together as a syndrome.

A retrospective survey was carried out for isolations of salmonellas from humans, foods and sewer swabs from food-handling premises for the period 1976–80.

The predominant serotypes isolated from humans were S. typhimurium, S. hadar, S. virchow and S. agona.

Salmonellas were found in less than 1% of cooked pork and poultry products and were not detected in cooked beef or lamb. The isolation rates for cooked offal and cooked open pet foods were 2·1% and 19·7% respectively. Isolation rates for uncooked meats ranged from 5% for beef to 36% for poultry. Most of the uncooked meats were sausages in which the predominant serotypes were S. derby, S. typhimurium, S. heidelberg and S. panama.

An attempt was made to investigate the relationship between serotypes isolated from humans and from sausages and sewer swabs. S. typhimurium and S. bredeney were predominant in humans, sausages and sewer swabs whilst S. derby, S. panama and S. give were predominant only in sausages and sewer swabs.

Influenza activity is subject to environmental factors. Accurate forecasting of influenza epidemics would permit timely and effective implementation of public health interventions, but it remains challenging. In this study, we aimed to develop random forest (RF) regression models including meterological factors to predict seasonal influenza activity in Jiangsu provine, China. Coefficient of determination (R2) and mean absolute percentage error (MAPE) were employed to evaluate the models' performance. Three RF models with optimum parameters were constructed to predict influenza like illness (ILI) activity, influenza A and B (Flu-A and Flu-B) positive rates in Jiangsu. The models for Flu-B and ILI presented excellent performance with MAPEs <10%. The predicted values of the Flu-A model also matched the real trend very well, although its MAPE reached to 19.49% in the test set. The lagged dependent variables were vital predictors in each model. Seasonality was more pronounced in the models for ILI and Flu-A. The modification effects of the meteorological factors and their lagged terms on the prediction accuracy differed across the three models, while temperature always played an important role. Notably, atmospheric pressure made a major contribution to ILI and Flu-B forecasting. In brief, RF models performed well in influenza activity prediction. Impacts of meteorological factors on the predictive models for influenza activity are type-specific.

Knowing the burden of influenza is helpful for policy decisions. Here we estimated the contribution of influenza-like illness (ILI) visits associated with laboratory-confirmed influenza among all clinic visits in a Senegal sentinel network. ILI data from ten sentinel sites were collected from January 2013 to December 2015. ILI was defined as an axillary measured fever of more than 37.5 °C with a cough or a sore throat. Collected nasopharyngeal swabs were tested for influenza viruses by rRT-PCR. Influenza-associated ILI was defined as ILI with laboratory-confirmed influenza. For the influenza disease burden estimation, we used all-case outpatient visits during the study period who sought care at selected sites. Of 4030 ILI outpatients tested, 1022 were influenza positive. The estimated proportional contribution of influenza-associated ILI was, per 100 outpatients, 1.2 (95% CI 1.1–1.3), 0.32 (95% CI 0.28–0.35), 1.11 (95% CI 1.05–1.16) during 2013, 2014, 2015, respectively. The age-specific outpatient visits proportions of influenza-associated ILI were higher among children under 5 years (0.68%, 95% CI: 0.62–0.70). The predominant virus during years 2013 and 2015 was influenza B while A/H3N2 subtype was predominant during 2014. Influenza viruses cause a substantial burden of outpatient visits particularly among children under 5 of age in Senegal and highlight the need of vaccination in risk groups.

A prospective multi-centre study was conducted to assess the microbiological pattern and prognostic factors of bacteraemia and their impact on clinical outcome. All patients admitted to 41 Italian hospitals over 2 months, from whom one or more clinically significant organisms were isolated from blood culture, were studied according to a standardized protocol and case definition. A total of 156 episodes of bacteraemia were identified in 20601 patients. There were 3·9 episodes of nosocomially acquired bacteraemia and 3·7 episodes of community-acquired bacteraemia per 1000 admissions. The most frequent pathogens isolated were Gram-negative bacteria (44·9%) but Gram-positive species accounted for 40·4% of episodes. Fungal infections due to Candida spp. were found in 3·8% of episodes, and multiple pathogens were recovered from 9·6% of episodes. The clinical response to bacteraemia was classified as sepsis in 90 episodes (57·7%), severe sepsis in 21 (13·5%) and septic shock in 26 (16·7%); 19 episodes (12·2%) showed no clinical response. The total in-hospital mortality was 25·0%. By multivariate logistic regression, the variables which independently predicted mortality were increasing age, the presence of septic shock, infection with Gram-positive bacteria or fungi and nosocomial acquisition.

The high incidence (80·1%) of Pseudomonas aeruginosa pyocine type 1 in bovine mastitis in Israel suggested some degree of selectivity under local conditions. Contrary to other reports, cattle and calves showed a high rate of faecal carriage of this organism. The water supply on farms was often contaminated. The presence of certain pyocine types in the udder, gut or water occasionally led to their transmission from one reservoir to another; however, many types did not seem to spread.

P. aeruginosa was found in association with infections in various animals and was present in many locations such as a mouse breeding house and a chick hatchery.

In a recent report (Topley, Wilson and Lewis, 1925) we described some observations on the rôle of the Twort-d'Herelle phenomenon in the epidemic spread of mouse-typhoid. In the experiments there recorded the lytic filtrate was administered by the mouth. The results obtained did not suggest that such administration exerted any appreciable influence on the spread of disease. It was shown, in a separate series of experiments, that intraperitoneal inoculation of such a filtrate afforded a marked degree of protection against subsequent inoculation of living cultures of B. aertrycke, provided that sufficient time had elapsed to allow of an immunising response, that no immediate protection was afforded by the inoculation of the lytic filtrate, and that neither immediate protection, nor subsequent immunisation, was afforded by the administration of the lytic filtrate by the mouth.

Hospital-level predictors of high rates of ‘Clostridium difficile-associated disease’ (CDAD) were evaluated in over 2300 hospitals across California, Arizona, and Minnesota. American Hospital Association data were used to determine hospital characteristics associated with high rates of CDAD. Significant correlations were found between hospital rates of CDAD, common infections and other identified pathogens. Hospitals in urban areas had higher average rates of CDAD; yet, irrespective of geographic location, hospital rates of CDAD were associated with other infections. In addition, hospitals with ‘high CDAD’ rates had slower turnover of beds and were more likely to offer transplant services. These results reveal large differences in rates of CDAD across regions. Hospitals with high rates of CDAD have high rates of other common infections, suggesting a need for broad infection control policies.