The results obtained point to a consistent relationship between lipolytic activity and bacteriolytic power on tubercle bacilli.

The least bactericidal extract was lung extract; the most powerful was pancreas extract.

Liver, thymus and lymphatic glands were strongly bactericidal.

Other organs, suprarenal glands, pig and cat spleen, human and cat kidney, human and ox brain, ox thyroid, cat lung, ox bone marrow and ox pituitary glands were found to be bactericidal to a lesser degree.

The human skin extract examined for bactericidal properties was fatty and cloudy in appearance and exceptionally rich in esterases1.

Even if exceptional in its esterase activity this sample of skin bears out the relationship between lipolysis and bacteriolysis of tubercle bacilli in a striking way, as it was also extremely bactericidal.

No difference was noticed between bovine and human tubercle bacilli in susceptibility to any gland extract examined.

Other acid-fast bacilli, though on the whole less susceptible than tubercle bacilli to the influence of these extracts, were bacteriolysed by them. They were also killed by one lung extract (pig's) which contained an unusually large amount of olein lipase and which had no effect on tubercle bacilli.

I wish to express my thanks to Dr W. Cramer for his kind advice and encouragement, to Dr Cobbett for his kindly criticism, to Professor Shennan and Dr Miller for human material, and to Dr Wang for several strains of tubercle bacilli.

The expenses of this Research were met in part by a grant from the Earl of Moray Trust.

Cases of western equine encephalitis in horses in 1987 in western USA and Manitoba, Canada were examined by backward trajectory analysis of winds. Culex tarsalis mosquitoes infected with western equine encephalitis virus could have been carried on southerly winds from Texas and Oklahoma to northern LTSA and from there to Manitoba. The presence of the Polar front over North Dakota and Minnesota at the end of July would have led to the landing of Cx. tarsalis in Montana and Wisconsin and prevented further carriage into Manitoba. Temperatures in southern Texas during the winter months (average daily maximum temperatures 19.7 °C and higher) would have permitted continuous transmission of western equine encephalitis virus by Cx. tarsalis in this area.

Weather factors involved in outbreaks from 1975–88 were analysed to see if epidemics in Manitoba (23 or more cases in horses) could be predicted. The conditions for epidemics could be defined as follows: (a) the number of cases in horses in LTSA was 98 or more, (b) winds were southerly with speeds 45 kmh-1 or higher, and (c) counts of Cx. tarsalis females/light trap per day were 3·2 or higher. There were 3 or fewer cases in Manitoba, when the number of cases in USA was 27 or less, even when Cx. tarsalis counts were higher than 3·2. With Cx. tarsalis counts below 3 and/or unsuitable winds, or the Polar front further south, the number of cases in Manitoba was between 0 and 17, even when the number of cases in USA was from 38–172. Without information on the extent of infection further south, the weather variables would probably be more useful in excluding the possibility of an epidemic in Manitoba than in predicting one.

In discussions of the origin of new infectious diseases, prominence is usually given to dramatic infections acquired from animals (Lassa fever, Marburg and Ebola viruses) or from the environment (legionellosis). But these infections do not spread from human to human, and their impact on mankind can never be catastrophic. If a new infectious agent is to pose a major threat to the human species, it will need to kill tens or hundreds of millions of people over a short period of time (a few years), before vaccines and antimicrobial agents can be developed or effective blocks to transmission established. The 1918 influenza pandemic (total deaths about 20 million) almost came into this world-shaking category, but many of the deaths were presumably due to secondary bacterial pneumonia and this was the pre-antibiotic era. A similar airborne pandemic occurring today could spread globally within weeks by air transport and would have a greater impact. Smallpox arose long before the world became one from an infectious disease point of view, and although it caused devastating epidemics it did not have the opportunity to develop into the ‘major threat’ category. A significant proportion of people recovered, less virulent strains of virus (variola minor) appeared, and an effective vaccine not only kept it under control in many continents but finally eliminated it from the world. The plague (Yersinia pestis) influenced the course of history in Asia and Europe [1] but oven in its respiratory form could not in those days be transferred rapidly from continent to continent.

At least 12 persons contracted clinical, and 4 persons subclinical Brucella melitensis infection during a brucellosis epidemic in the spring and summer of 1983 in Southern Germany, a region which had been free of this disease for the past 20 years. All cases of illness were traced to one infected herd of sheep. The presence of antibodies against B. melitensis was examined in 72 sera of infected patients using the following tests: agglutination, Coomb's test, two complement fixation tests with different antigen preparations (CFT 1 and 2), IgG and IgM enzyme-linked immunosorbent assay (ELISA), and opsonophagocytosis; and the occurrence of cross-reacting antibodies against Yersinia enterocolitca O9 was investigated in the agglutination and complement fixation tests. Sera from 100 blood donors and 112 other people with close contact with sheep were also examined. The results revealed the need to consider an intermediate range in the interpretation of ELISA results – due to elevated values of persons in groups at risk but without clinical signs of illness. In all other tests, however, such persons revealed the same cut-off levels as the general population. Results from all initial sera of infected persons revealed titres of optical densities above the baseline levels determined in the present study, with the exception of the Coomb's and CFT 2 tests. The agglutination test, but not brucella CFT2, revealed complete cross-reactivity between Y. enterocolitica O9 and B. melitensis. ELISA stood out as the only test which is suited to diagnosis of both recent and past infection, since ELISA IgM determination permits conclusions about the time of the onset of illness, and determination of IgG may still yield values above the cut-off level up to G23 days after the onset of illness. In 2 of the 1G infected persons, IgG ELISA was the only test revealing previous infection 424 and 528 days after the onset of illness. A procedural scheme is presented which may help to simplify the diagnosis of brucellosis.

Two tests are described for detecting antibody to the type-specific opacity factor (OF) of group A streptococci. This antibody was detected among patients convalescent from streptococcal sore throat in two communities in which out-breaks due to opacity factor-producing strains of group A streptococci occurred.

In an outbreak due to streptococci of M-type 22 there was a close correspondence between the distribution of anti-OF and of bactericidal M-antibody for the type. In a smaller outbreak due to M-type 58 streptococci, however, M-antibody was detected more often than antibody of OF.

Suspensions and dried preparations of vaccinia virus were exposed to γ-rays in cobalt-60 sources. Suspensions completely inactivated by 6–8 × 105 rad. retained measurable immunogenicity. Dried preparations could not be completely in-activated even by doses of 11 × 106 rad., although the inactivation apparently followed first-order kinetics until about one particle in 107 survived, suggesting that the populations of vaccinia virus in the preparations were heterogeneous.

Most outbreaks of viral hepatitis in India are caused by hepatitis E. This report describes an outbreak of hepatitis B in a rural population in Haryana state in 1997. At least 54 cases of jaundice occurred in Dhottar village (population 3096) during a period of 8 months; 18 (33·3%) of them died. Virtually all fatal cases were adults and tested positive for HBsAg (other markers not done). About 88% (21/24) of surviving cases had acute or persistent HBV/HCV infections; 54% (13/24) had acute hepatitis B. Many other villages reported sporadic cases and deaths. Data were pooled from these villages for analysis of risk factors. Acute hepatitis B cases had received injections before illness more frequently (11/19) than those found negative for acute or persistent HBV/HCV infections (3/17) (P = 0·01). Although a few cases had other risk factors, these were equally prevalent in two groups. The results linked the outbreak to the use of unnecessary therapeutic injections.

All the four types of acid-fast bacilli used in this investigation have proved virulent for the golden hamster. Of the four types the bovine is the most virulent for the species and, after subcutaneous inoculation, gives rise to severe generalized progressive tuberculosis, the lesions containing enormous numbers of tubercle bacilli. The human type is also highly virulent for the hamster and produces general progressive tuberculosis closely resembling that set up by bovine bacilli. Caseation of the lesions in the organs was, however, less extensive in the human than in the bovine infections but there was little difference in this respect between the glandular lesions of the two infections, and multiplication of bacilli was as profuse in one as in the other. Avian bacilli can readily multiply in the tissues of the hamster and cause death, but appear unable to give rise to macroscopic tuberculous lesions. Only one hamster was injected with avian bacilli and the result of this experiment is not in accord with those of Balfour-Jones already quoted. The vole bacillus is less virulent for the hamster than either the bovine or the human type of bacillus. Of the two hamsters injected with this type of bacillus one was killed 152 days later, its general condition then being good and its body showing plenty of subcutaneous fat. Nevertheless the organs were found to contain tuberculosis-like lesions, numerous in the spleen and liver, and the lymphatic glands generally were enlarged. The remaining hamster died 188 days after inoculation and showed generalized disease very similar to that in the last hamster. The glandular and visceral lesions of both hamsters contained very numerous acid-fast bacilli but, in striking contrast to those produced by bovine and human bacilli, showed no evidence of caseation.

Acid-fast bacilli were present in the faeces of all the hamsters; they were numerous in those of hamsters 3, 4, 5 and 2 and relatively sparse in those of hamsters 1 and 6.

In the Republic of Korea, despite the introduction of one-dose universal varicella vaccination in 2005 and achieving a high coverage rate of 98.9% in 2012, the incidence rate has been increased sevenfold. This study aimed to investigate time trends of varicella incidence rate, assessing the age, period and birth cohort effects. We used national data on the annual number of reported cases from 2006 to 2017. A log-linear Poisson regression model was used to estimate age–period–cohort effects on varicella incidence rate. From 2006 to 2017, the incidence of varicella increased from 22.5 cases to more than 154.8 cases per 100 000. Peak incidence has shifted from 4 to 6 years old. The estimated period and cohort effects showed significant upward patterns, with a linear increasing trend by net drift. There has been an increase in the incidence among the Korean population regarding period and cohort despite the universal vaccination of varicella vaccine. Our data suggest the need for additional studies to address the current gap in herd immunity.

Staphylococcal colonization and infection were studied prospectively in infants, mothers and households after childbirth at home and in hospital. Infants were treated prophylactically with frequent applications of ‘Ster-zac’ hexachlorophane dusting powder. Some were treated in addition with ‘Naseptin’ nasal disinfectant cream.

The incidence of staphylococcal sepsis in infants was much less than before the adoption of hexachlorophane prophylaxis. The sepsis rate was further reduced when ‘Naseptin’ was used in addition to hexachlorophane. Of the two prophylactic agents, hexachlorophane was the more convenient and probably the more effective. ‘Naseptin’ was difficult to employ correctly and unsuitable for routine use.

The treatment of infants with disinfectants reduced nasal carriage markedly in infants and to a smaller extent in mothers. Both agents contributed to the reductions which persisted for some weeks after treatment ceased.

Breast abscesses were almost entirely confined to mothers of infants who became nasal carriers by the second week of life.

Staphylococcal colonization of infant's skin was greater when they wore impervious garments, probably because skin moisture increased.

A method is described for comparing the resistance to penetration by aqueous fluids, under rubbing contact, of a representative series of fabrics. Untreated woven fabrics are rapidly penetrated, but some non-woven synthetic materials resist penetration for much longer and tightly woven proofed cotton fabrics for prolonged periods, even after repeated washing and sterilizing. If a wetting agent is added to water, penetration occurs more quickly, but fabrics containing natural cotton are penetrated more slowly by serum.

The same fabrics were examined by a test designed to simulate transfer of dry participate material, e.g. skin scales, through them during nursing contact. The proportionate differences observed were much greater than for air dispersal during exercise and closely resembled those obtained by a laboratory rubbing test. In particular, one of the non-woven fabrics showed much greater relative penetration when examined by these methods than the relative dispersal of skin scales through it during exercise.

The annual incidence of meningococcal disease (meningitis and septicaemia) in Taiwan was 0·94/105 population in 1953. It then declined to below 0·001 from 1980 to 1987, and re-emerged in 2000 with a rate of 0·07/105 population. In 2001 there was a further increase in incidence (43 cases, 0·19/105). Of 43 isolates of Neisseria meningitidis available for this study, including 41 from patients treated in 2001, three (7·0%) were penicillin insensitive (MIC [ges ]0·12 μg/ml), though all were β-lactamase negative; 16 (37·2%) were resistant to trimethoprim–sulphamethoxazole sulphamethoxazole (MIC [ges ]4/76 μg/ml). Serogrouping and genotype analysis revealed nine domestic clones. None of the 43 patients had any relationship (travel or contact history) with the 2000 or 2001 Hajj pilgrimage. Epidemiological information and typing results suggested wide dissemination of a limited number of domestic clones of N. meningitidis, manifesting as serogroups W-135, B and Y. Two clones of serogroup W-135 involved in the outbreak were genetically distinct from the 2000 or 2001 Hajj-related W-135 clone.

This paper describes an investigation into the successful preservation at room temperature of the bacteriophage H1 of Corynebacterium ulcerans U 103 which was extremely labile when in suspension at 4° C.

Cooling at a rate of 1° C./min. showed that the survival decreased logarithmically at temperatures between – 14 and – 45° C. Survival of broth suspensions of the corynebacteriophage were found to increase proportionally with an increase in the rate of cooling though there was a marked drop in survival at rates of approximately 900° C./min. The addition of peptone solutions was found to increase the survival over the range studied, whereas the addition of sucrose solutions had only a slight effect.

By avoiding freezing damage by cooling at rates of 450° C./min. in (a) 20% peptone solution, (b) 20% peptone and 10% sucrose, and (c) 20% peptone, 10% sucrose and 2% sodium glutamate, a study was made of the drying stage of the freeze-drying process. On drying at controlled temperatures it was found that there was no damage on rewarming to temperatures below – 21° C. after cooling to – 196° C., but that the survival immediately after drying in the absence of glutamate, showed a logarithmic relationship with the temperature of drying, lower temperatures giving better survival.

On storage for a period of 3 months at room temperature in vacuo and darkness, there was no appreciable loss in survival in the mixtures though suspensions in peptone alone showed a slight decrease. At higher temperatures this decrease in survival could be differentiated into two types of damage, each of which could be influenced by the presence of sucrose or glutamate.

We are grateful to Professor H. R. Carne for providing the initial sample of bacteriophage H 1 of Corynebacterium ulcerans U 103, and to Professor R. I. N. Greaves for his interest and encouragement during the course of this investigation.

A 9-year time-series of genotyped human campylobacteriosis cases from the Manawatu region of New Zealand was used to investigate strain-type seasonality. The data were collected from 2005 to 2013 and the samples were multi-locus sequence-typed (MLST). The four most prevalent clonal complexes (CCs), consisting of 1215 isolates, were CC48, CC21, CC45 and CC61. Seasonal decomposition and Poisson regression with autocorrelated errors, were used to display and test for seasonality of the most prevalent CCs. Of the four examined CCs, only CC45 showed a marked seasonal (summer) peak. The association of CC45 with summer peaks has been observed in other temperate countries, but has previously not been identified in New Zealand. This is the first in-depth study over a long time period employing MLST data to examine strain-type-associated seasonal patterns of C. jejuni infection in New Zealand.

This paper describes a search for Gram-negative bacteria in an operating theatre and the steps taken to reduce the level of environmental contamination.

A high rate of infection in clean wounds prompted a bacteriological survey. Potential sources of infection found, and the measures employed are described in the hope that others may be encouraged to examine familiar equipment critically and to improve hygiene even in old premises.

The choice, design, use and care of cleaning and sterilizing equipment were open to criticism. In particular, a currently popular floor-scrubbing machine provided a breeding ground for Pseudomonas aeruginosa and was distributing it in the theatre environment.

1. Three strains of virus were isolated in suckling mice from the blood of three patients suffering from dengue during a local outbreak of the disease.

2. One strain was adapted to adult mice and identified as a dengue virus of type 1. The identification was confirmed by workers in America.

3. Evidence is presented that the other two strains of virus are similar to the one fully identified.

4. Attention is drawn to the need for detailed work to find a more sensitive method of isolation for dengue viruses.

In this study within-herd prevalence of Salmonella Dublin was investigated in three age groups (calves, young stock, adult cows) during five herd visits at 3-month intervals of 14 endemically infected dairy herds. A total of 10162 paired faecal cultures and antibody measurements were used to calculate the age and temporal dynamics of seroprevalence and prevalence of positive faecal cultures. Faecal culture-positive prevalence was generally low. It was highest (5·4%) in calves during December to February. Seroprevalence varied from 0% to 70% between herds, but was generally more stable in young stock and adult cows than in calves. Hierarchical mixed-model results showed that seroprevalence was associated with the bacteriological status in calves and cows, but not in young stock. These results can be used to develop and validate theoretical infection dynamics models and to design effective control programmes for Salmonella Dublin in dairy herds.

An outbreak of leptospirosis occurred in the South of Belgium, during August 2012, in teenagers who participated in two consecutive adventure scout camps near the Semois river. Among the symptomatic patient population (ten scouts), clinical manifestations included headache (70%), myalgia (50%), fever (50%), bilateral conjunctival injection (50%), general malaise (30%), vomiting (20%), anorexia (20%) and cough (20%). Some of the cases presented elevated blood creatinine (40%), or proteinuria (30%). Three patients were confirmed by serology and one by polymerase chain reaction. Potential risk factors included direct contact with a muskrat and indirect contact with potentially contaminated environments including the river water. Prospective environmental investigation carried out near the river banks 2 weeks after the outbreak identified Ondatra zibethicus (muskrat) as one Leptospira sp. reservoir.

An unlinked anonymous survey was conducted to measure the prevalence of selected markers for HIV, hepatitis B and C infection in recruits to the UK Armed Forces to inform future screening and hepatitis B vaccination policies. During 2007, nearly 14 000 left-over samples taken from new recruits for blood typing were collected, unlinked from identifiers and anonymously tested for HIV, hepatitis C and current and past cleared hepatitis B infection. Overall, serological evidence of HIV and hepatitis C was found in 0·06% and 0·06% of recruits, respectively. Evidence of past cleared and current hepatitis B infection was found in 3·63% and 0·37% of recruits, respectively. Overall, prevalence rates were broadly consistent with UK population estimates of infection. However, HIV and hepatitis B prevalence was higher in recruits of African origin than in those from the UK (P<0·0001). Screening for these infections is an option that could be considered for those entering Services from high-prevalence countries.

Here we evaluated hospitalisation rates and associated risk factors of human immunodeficiency virus (HIV)-infected individuals who were followed up in an Italian reference hospital from 1998 to 2016. Incidence rates (IR) of hospitalisations were calculated for five study periods from 1998 to 2016. The random-effects Poisson regression model was used to assess risk factors for hospitalisation including demographic and clinical characteristics. To consider that more events may occur for the same subject, multiple failure-time data analysis was also performed for selected causes using the Cox proportional hazards model. We evaluated 2031 patients. During 13 173 person-years (py) of follow-up, 3356 hospital admissions were carried out for 756 patients (IR: 255 per 1000 py). IR decreased significantly over the study period, from 634 in 1998–2000 to 126 per 1000 py in 2013–2016. Major declines were detected for AIDS-defining events, non-HIV/AIDS-related infections and neurological diseases. Older age, female sex, longer HIV duration and HCV coinfection were associated with a higher hospitalisation risk, whereas higher CD4 nadir and antiretroviral therapy were associated with a reduced risk. Influence of advanced HIV disease markers declined over time. Hospitalisation rates decreased during the study period in most causes. The relative weight of hospitalisations for non-AIDS-related tumours, cardiovascular, respiratory and kidney diseases increased during the study period, whereas those for AIDS-defining events declined.