1. Additional quantitative studies of the survival of micro-organisms in aerosols are reported.

2. Substitution of nitrogen for oxygen in the ambient medium decreases k′2, the rate of secondary loss of viability of M. candidus, Esch. coli and S. marcescens, by 30–50%.

3. The rate of primary decay (k′1) of Esch. coli does not appear to be affected by a similar change of atmosphere.

4. The rate of secondary decay, k′2, of M. candidus appears to increase two-to three-fold for 10°C. increments in temperature.

5. Treatment of suspensions of Esch. coli with petroleum ether alone or containing lipid material increases k′1 in aerosols generated from such suspensions.

6. Treatment of Myco. phlei with petroleum ether appears to lower resistance to subsequent sonic irradiation.

These observations are consistent with the hypothesis that differences in the physical and chemical structure of micro-organisms are reflected in constants k′1, k′2 and b.

We gratefully acknowledge the effective interest of two former assistants, T. Grant Maple and Eugene Mills, as well as the careful, effective, and conscientious work of our technical assistants, Ann Barr, Nora Galins, Cynthia Hartwig, Grace C. Leigh, Elizabeth Neidhardt, Paulette Slaney and Martha Szerslip, who have at different times helped secure the data presented here. Mrs Joseph J. Ecker deserves special thanks for care in the preparation of the manuscript.

A mathematical model was used to evaluate the impact of the Italian Measles National Elimination Plan (NEP), and possible sources of failure in achieving its targets. The model considered two different estimates of force of infection, and the possible effect on measles transmission of the current Italian demographic situation, characterized by a below-replacement fertility. Results suggest that reaching all NEP targets will allow measles elimination to be achieved. In addition, the model suggests that achieving elimination by reaching a 95% first-dose coverage appears unlikely; and that conducting catch-up activities, reaching high vaccination coverage, could interrupt virus circulation, but could not prevent the infection re-emerging before 2020. Also, the introduction of the second dose of measles vaccine seems necessary for achieving and maintaining elimination. Furthermore, current Italian demography appears to be favourable for reaching elimination.

A method of drying bacteria is described, in which the bacterial suspension was made in 40% sodium glutamate, and 0·1 ml. volumes of this in 8 ml. ampoules were dried in vacua while being held in a water bath at 25°C. After 1 hr. with the pump still running, the ampoules were immersed in water at 100° C. The partly dried suspension expanded rapidly into a homogeneous white foam. After 30 min. the ampoules were taken off the manifold; small tubes containing dry P2O5 were inserted in the ampoules which were then sealed in air. Preliminary results with three organisms, Salmonella ndolo, Staphylococcus aureus and Serratia marcescens showed high survivals immediately after the ‘foaming’ period, and good stability after 1 or 2 days at 100°C.

Children may be at higher risk for carriage of antimicrobial-resistant bacteria because of higher usage of antimicrobials. They also have higher rates of Shiga toxin-producing Escherichia coli (STEC) infections than other population groups. Some infections, particularly in children, are asymptomatic, but still lead to the excretion of large numbers of bacteria and viruses that may cause clinical disease in other individuals. That is one reason why, in Lower Saxony as in other German federal states – asymptomatic carriers of STEC are excluded from nurseries and schools until three consecutive stool samples test negative in order to prevent secondary cases. The prevalence of children who are asymptomatic STEC carriers is unknown. But if it is high, this measure would have substantial socioeconomic effects on families. Infections with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are an increasing problem for public health, especially for hospitals. However, there are no reliable estimates of the prevalence of asymptomatic ESBL-E carriers in Lower Saxony, as there is no mandatory requirement to report these carriers. In order to discuss the exclusion policies for children attending nurseries and ascertain a baseline of ESBL-E carriers, we conducted a cross-sectional study. The aim was to determine the prevalence of ESBL-E and STEC and identify risk factors for carriage in nursery children without diarrhoea (asymptomatic) aged 0–6 years in four selected districts in Northern Germany. During April–September 2014, we collected stool specimens with the support of voluntarily participating nurseries. We tested for STEC by PCR and for ESBL-E on chromogenic agar. Questionnaires answered by parents contained data on eating and drinking habits, outdoor activities, prior antibiotic treatment and animal contact for each participating child. We compared the epidemiological characteristics of ESBL-E carriers vs. non-carriers by using univariable analysis (P value, odds ratio and 95% confidence interval). We could not perform a statistical analysis for STEC carriers due to the low numbers of positive STEC specimens. Of 224 asymptomatic nursery children, we found a prevalence of 2·3% for ESBL-E carriage and 0·5% for STEC carriage. Asymptomatic ESBL-E carriers were more likely to have consumed raw milk, have had contact with pet rodents, or to have taken antibiotics during the preceding 6 months. We also found a high proportion of raw milk consumption (11%). We suggest that the low STEC prevalence in asymptomatic children supports the current practice of excluding STEC carriers from nurseries. The association between ESBL-E carriage and raw milk consumption and contact with pet rodents needs further investigation.

Worldwide, early detection systems have been used in public health to aid the timely detection of increases in disease reporting that may be indicative of an outbreak. To date, their application to animal surveillance has been limited and statistical methods to analyse human health data have not been viewed as being applicable for animal health surveillance data. This issue was investigated by developing an early detection system for Salmonella disease in British livestock. We conclude that an early detection system, as for public health surveillance, can be an effective tool for enhanced surveillance. In order to implement this system in the future and extend it for other data types, we provide recommendations for improving the current data collection process. These recommendations will ensure that quality surveillance data are collected and used effectively to monitor disease in livestock populations.

Studies of the effect of Hong Kong (HK) influenza vaccine were made in adults and children in Great Britain during 1968 and 1969. The vaccines were administered intramuscularly and also by intranasal spray. The serum antibody response was studied in 284 subjects. Most developed rising titres to vaccine given intramuscularly and few to vaccine given intranasally. Deoxycholate-split vaccine was as potent as conventional whole virus vaccine. Antibody titres were maintained for months. Over 4000 subjects in factories, offices and schools were observed during the epidemic. The incidence of disease was not significantly reduced by either form of vaccination. A survey was made of epidemics in boarding schools in which some of the pupils had been vaccinated, in six with commercial polyvalent vaccine and in five with HK; there was a lower incidence of influenza in two schools vaccinated 2 or 4 weeks earlier with HK vaccine.

A relatively simple method for the detection of intra-specific variation of Mycobacterium bovis is described, based on the ability of strains to utilize or remove amino acids from solution. Using the method, 31 strains of M. bovis, isolated from badgers and cattle, have been divided into four major groups with some additional sub-groups and intermediate strains. Preliminary results suggest that the biotypes observed are relatively stable. The method was used in the investigation of an outbreak of bovine tuberculosis in cattle in Gloucestershire where badgers were implicated as a source of infection. The results suggested that transmission of infection had occurred on at least two or three separate occasions. It is suggested that the method could be used in studying the epidemiology of bovine tuberculosis in wild animals, cattle and man.

A total of 321 Salmonella typhimurium strains of bovine origin obtained in northern Japan during the period 1970–1979 were tested for drug resistance and detection of conjugative R plasmids. Three hundred and eighteen (99·1 %) of these strains were resistant to one or more drugs. The isolation frequency of multiply drug-resistant strains tended to increase year by year. Two hundred and thirty-seven (74·5%) of these resistant strains carried conjugative R plasmids. A total of 308 R plasmids including 174 (56·5 %) thermosensitive (ts) R plasmids were derived from the 237 drug-resistant strains, indicating that 71 (30·0%) strains have two different conjugative R plasmids in a single host cell. Of the 308 R plasmids examined for fertility inhibition (fi), 167 ts and 131 non-ts R plasmids were fi−. Of the 60 ts R plasmids examined for incompatibility, 50 were classified into H1 group and 10 into H2 group. Of the 52 non-ts R plasmids examined, 35 were classified into the Iα group and the remaining plasmids were untypable in our tests. Mercury resistance marker was found in about 20% of H1 R plasmids coding for multiresistance, and all of H2 R plasmids coded for resistance to tellurite. The clonal distribution of an S. typhimurium strain which carried an H1 R plasmid coding for resistance to six drugs and mercury was recognized in 1978 and 1979.

To investigate the potential of poultry products as the source of human infections associated with quinolone-resistant campylobacters, 140 human and 75 poultry isolates of nalidixic acid-resistant campylobacters were collected between 1996 and 1998, and analysed by two molecular typing methods. By the analysis of restriction fragment length polymorphism of the flagellin gene, 33 distinct patterns were obtained, with 18 of which shared by both human (89%) and poultry (93%) isolates. By the pulsed-field gel electrophoresis of SmaI-restricted macrofragments, 105 different profiles were obtained, and 11 were found in both human (40%) and poultry (23%) isolates. When the two typing methods were combined, 112 unique genotypes were obtained, 11 of which were shared by both populations, including 53 (38%) human isolates and 14 (19%) poultry isolates. Although domestic poultry products are still important sources of the quinolone-resistant campylobacter infections in humans, there are other factors that might contribute to these increasing infections simultaneously. A more stringent policy in the use of antimicrobial agents in food animals can no longer be ignored.

To assess the measles seroepidemiology of healthcare workers (HCWs), from 2004 to 2009 all newly recruited staff at a university hospital in Taiwan, were tested for specific immunoglobulin G antibodies for measles virus using enzyme-linked immunosorbent assays. A total of 1584 HCWs were included. The positivity rate of measles antibody for physicians and nurses was about 90%. The positivity of measles antibody in different age groups was 78·1%, 93·9% and 94·2% for 20–29, 30–39 and ⩾40 years age groups, respectively. Equivocal results were more frequent in the 20–29 (17·1%) years age group. A lack of antibody against measles was reported for 66 (4·2%) of those tested. Medical student (8·3%) and housekeeping personnel (5·3%) had the greatest lack of antibodies. This study demonstrates the waning measles immunity in younger HCWs in Taiwan, which poses the potential risk of nosocomial transmission of measles. Periodic surveillance and revaccination of susceptible HCWs is recommended.

1. Sodium fluoracetate (1080) has been tested in the field as a poison for Rattus norvegicus and R. rattus.

2. Direct poisoning (without Prebaiting) was used in thirteen tests on R. norvegicus. In eight of these tests censuses showed kills of at least 89% in three tests the poison failed, and in two the results were equivocal.

3. Of three similar tests against R. rattus two were successful and one was a failure.

4. Six tests of 1080 after prebaiting gave five successes (including one against R. rattus), and one in which the estimated kill was about 82%.

5. In five out of six tests populations of R. norvegicus which had survived baiting with 1080 showed shyness (refusal) of the poison when it was given in a new bait base.

6. The LD 50 of 1080 for a strain of white rats was found to be 3·8 mg./kg. (approx. range 2·8–5·2).

7. A number of wild brids and some domestic animals were accidentally killed during the tests despite stringent precautions taken in laying the bait and in warning occupiers.

8. It is concluded that: (a) although 1080 is probably more effective in direct poisoning than other poisons used in the past, it does not give as consistent results as the standard poisons do after prebaiting; (b) 1080 is too dangerous for general use.

A subtyping methodology for Campylobacter, Comparative Genomic Fingerprinting (CGF40), has been described recently. The objective of this study was to assess the utility of CGF40 as a tool to enhance routine public health surveillance of campylobacteriosis. Isolates of Campylobacter from across the province were requested and sent for CGF40 subtyping. Epidemiological data from cases reported to public health officials in Nova Scotia, Canada, from January 2012 to March 2015 were linked with blinded CGF40 subtyping results. CGF40 was epidemiologically valid; subtyping discerned known epidemiologically related isolates and augmented case-finding. Predominant sources and locations of subtype detection from the national reference database showed some study subtypes were rare and even novel to the database, while others were more commonly identified over multiple years and with exposures locally and internationally. A case-case study design was applied to examine risk factors for the most common CGF40 subtypes detected. Differences in the epidemiology of different CGF40 subtypes were observed. Statistically significant associations were noted for specific subtypes with rural residence, local exposure, contact with a pet dog or cat, contact with chickens, and drinking unpasteurized milk. With prospective use, CGF40 could potentially identify unrecognized outbreaks and contribute to epidemiological investigations of case clusters.

An enzyme-linked immunoassay (ELISA) has been developed to detect serum Immunoglobulin antibodies G and M to Treponema hyodysenteriae in vaccinated, experimentally infected and naturally infected swine. Naturally infected swine gave ELISA titres that were similar to experimentally infected swine, but were significantly less than the titres of vaccinated swine. When serum from naturally infected swine was used to probe nitrocellulose blots of sodium dodecyl sulphate–polyacrylamide gel electrophoresed whole cell proteins of T. hyodysenteriae, the immunoblotting patterns showed IgG antibodies were produced against many T. hyodysenteriae protein antigens and against lipopolysaccharide (LPS). The IgG antibodies directed against LPS were serotype-specific for that LPS and could be used to identify the serotype involved in the T. hyodysenteriae infection in that herd. IgM immunoblots also reacted with the many protein antigens but were less specific for LPS antigen, with a substantial degree of crossreaction between the LPS of all serotypes.

The data demonstrate that a microplate enzyme-linked immunosorbent assay, coupled with immunoblotting, is a very specific and sensitive test for detection of antibody to Treponema hyodysenteriae in swine.

A dengue vaccine is expected to be available within a few years. Once vaccine is available, policy-makers will need to develop suitable policies to allocate the vaccine. Mathematical models of dengue transmission predict complex temporal patterns in prevalence, driven by seasonal oscillations in mosquito abundance. In particular, vaccine introduction may induce a transient period immediately after vaccine introduction where prevalence can spike higher than in the pre-vaccination period. These spikes in prevalence could lead to doubts about the vaccination programme among the public and even among decision-makers, possibly impeding the vaccination programme. Using simple dengue transmission models, we found that large transient spikes in prevalence are robust phenomena that occur when vaccine coverage and vaccine efficacy are not either both very high or both very low. Despite the presence of transient spikes in prevalence, the models predict that vaccination does always reduce the total number of infections in the 15 years after vaccine introduction. We conclude that policy-makers should prepare for spikes in prevalence after vaccine introduction to mitigate the burden of these spikes and to accurately measure the effectiveness of the vaccine programme.

Various variables that might influence the rapid and sustained virological response to recombinant PEG-IFN-α-2a were explored in Iraqi HCV-infected patients with haemoglobinopathy. Forty-three patients were evaluated for the relationship between rapid virological response (RVR), IL-28B polymorphism, viral load, liver enzyme levels, blood group, ultrasound findings, or HCV genotype and the sustained virological response (SVR) achievement. The overall RVR was 55·81% while the overall SVR was 53·49%. SVR in patients that achieved RVR was 82·61% (P = 0·0004). A significant association was found between initial alanine transaminase levels and viral load with SVR achievement (P = 0·025) and (P = 0·004), respectively. Thirty-two (74%) out of 43 of our samples were host genotyped at the IL-28B locus as CC, a significant association was found between CC group and SVR achievement (P = 0·04). Of our samples, 23/43 (53%) were typed as HCV genotype 4, 10/43 (23%) as genotype 1, 9/43 (20·9%) as genotype 3 and 1/43 (2·3%) as genotype 2. A significant association was found between genotype 3 and SVR achievement (P = 0·006). Multivariate analysis showed that only RVR achievement independently associated with SVR in the Iraqi population (P = 0·00). These results can be used to classify the patients requiring the more expensive new direct-acting antiviral drugs.

This article describes an outbreak of Q fever involving 24 men (five prison officers and nineteen detainees) in one of H.M. Detention Centres. The evidence collected points strongly to the consumption of raw milk as the route of infection. This appears to be the first milk-borne outbreak of Q fever to be reported in Britain.

Following its reintroduction in 1978 influenza A H1N1 spread widely in the child population. By the autumn of 1979, 75% of 11-year olds entering a boys' boarding school had detectable antibody. The protective effect of previous experience could be assessed during two outbreaks in the school. In the first outbreak in 1979, 90% of those known to have been infected in the previous year were protected against reinfection. In 1983 after strains of the H1N1 subtype had undergone antigenic drift a large outbreak occurred. It was estimated that past infection conferred protection against clinical influenza in 55%. Where past infection resulted in the presence of antibody which reacted with the outbreak strain the attack rate was further reduced. A large number of sub-clinical infections was detected in all groups.

This paper describes a matched case-control study to determine the efficacy of BCG vaccine in preventing the occurrence of leprosy in southern Malaŵi, a previously unstudied area. The BCG immunization rate amongst 145 individuals with leprosy was 44.8%, compared to 62.5% in 290 matched controls. The protective efficacy of BCG vaccine against leprosy in this region was estimated to be 63.6%; smallpox immunization had no effect. These findings support the view that BCG vaccine should be considered as a control measure in areas where leprosy is endemic.

Reporting of percutaneous injuries (PIs) to the Chinese Exposure Prevention Information Network (EPINet) became mandatory for all public and tertiary referral hospitals in Taiwan in 2011. We have estimated the number of microbially contaminated PIs and the national PI incidence using a retrospective secondary data analysis approach to analyse 2011 data from the Chinese EPINet to determine the types of PI, mechanisms of occurrence and associated risks. The results revealed a national estimate of PIs between 6710 and 8319 in 2011. The most common incidents for physicians were disposable syringes, suture needles, and disposable scalpels; while for nurses they were disposable syringes, intravenous catheters, and lancets. About 13·0% of the source patients were seropositive for hepatitis B virus (HBV) surface antigen, 13·8% were seropositive for hepatitis C virus (HCV), and 1·1% seropositive for human immunodeficiency virus (HIV). From these results we estimate that annually 970 full-time healthcare workers (HCWs) would be exposed to HBV, 1094 to HCV, and 99 to HIV. This study improves our understanding of the mechanisms and risks of PIs and informs the development of more efficient preventive measures to protect HCWs from such injuries.

For some years past a careful record has been kept of the method of feeding, not only of all children dying of epidemic diarrhoea, but also of all babies under one year of age in the houses of the working classes, which are visited year by year in the course of routine house-to-house inspections by the sanitary inspectors in my department. It is impossible to ask the necessary questions at every house, but in most houses information has been given without difficulty, and it may be taken as certain that the 1259 babies living in 10,308 houses who are classified in the first four columns of Table I belong approximately to the same social stratum as the 121 babies dying from diarrhoea who are classified in the four last columins of the same table.