As a result of some preliminary investigations upon the aetiology of an asthmatic type of disability among workers in carding-rooms of cotton mills, Maitland, Heap and Macdonald (1932) showed that it was possible to extract from some samples of cotton dust a substance which gave the biological reactions of histamine. The dust was that to which affected workers would be exposed. The amount of histamine recovered varied from 0·02 mg. to less than 0·004 mg. per g. of dust. Different bulk samples of dust contained unequal amounts, and the amount also varied in different fractions of one sample graded according to the size of dust particles. It was thought that the finer fractions contained the larger amounts of histamine and that some bulk samples were, relatively at any rate, histamine free.

The seroprevalence of human T-lymphotropic virus type I (HTLV-I), in relation to that of human immunodeficiency virus type 1 (HIV-1), was determined in a comparative unlinked anonymous antenatal and neonatal (for indirect measurement of maternal antibodies) serosurvey in the Gauteng region of South Africa, using dried blood spots (DBS) and modified particle agglutination assays. Samples were confirmed to be antibody positive by western blot. A total of 2582 DBS collected during 1993 and 1994 from subjects of African, European and coloured origin were tested. Ten were confirmed as positive for HTLV-I and 128 for HIV-1. No antibodies to HTLV-I or HIV-l were demonstrated in the 221 women of European and coloured origin who were screened. The HTLV-I seroprevalence rate in subjects of African origin appeared to increase from 0% in 1993 to 0·49% in 1994, while HIV-1 seroprevalence rates of 5·2% and 5·4% were recorded for 1993 and 1994 respectively. No significant differences in HTLV-I and HIV-1 seroprevalence rates were noted for the two areas investigated. These results indicate that HTLV-I should be included in infection control programs, and provide baseline data for monitoring the possible spread of HTLV-I in the heterosexual population in this region.

The protection afforded by similar concentrations of different dengue virus serotypes against a subsequent challenge of West Nile virus was studied in hamsters. The New Guinea C strain of dengue 2 virus gave the best protection. It was found that the anamnestic neutralizing antibody response induced by the challenge West Nile virus against West Nile virus in hamsters, previously immunized with dengue 2 virus, might play a major role in the cross-protection observed in this system.

1. A description is given of active forms and cysts of an amoeba found in wild London rats, and morphologically identical with E. histolytica.

2. When inoculated into the caeca of young rats, the amoebae invade the wall and produce lesions.

3. Acute infections produced in experimental rats respond to treatment with emetine hydrochloride.

4. The naturally infected rats were restricted to a localized focus, in which cases of human amoebiasis were discovered, thus providing circumstantial evidence of the human origin of the infection, and throwing light on the possible role of rats as reservoir hosts.

Protein A of Staphylococcus aureus contains a polymorphic Xr-region characterized by a tandem repeat of eight amino acid units. In this study, the diversity of genes encoding the repeat regions and their relatedness among S. aureus strains was analyzed. Ten different protein-A types characterized by repeat numbers 4–13 were identified in a total of 293 clinical isolates. The protein-A type with 10 repeat units (10 repeats) in the Xr-region was most frequently detected in methicillin-resistant S. aureus, whereas the majority of methicillin- susceptible strains were distributed almost evenly into protein-A types with 7–11 repeats. Strains that belonged to a single coagulase type were classified into multiple protein-A types, e.g. strains with the common coagulase types II and VII were differentiated into 7 and 8 protein-A types, respectively.

Nucleotide sequence analysis of the Xr-region of 42 representative strains revealed the presence of 37 different genotypes (spa types), which were constituted by a combination of several of 24 different repeat unit genotypes. Based on the similarity in arrangement of repeat unit genotypes, 34 strains with different repeat numbers were classified into 5 genetic clusters (C1–C5). The clusters C1, C2 and C3 consisted exclusively of strains with identical coagulase types II, III, and IV, respectively. These findings suggested that the protein-A gene of S. aureus has evolved from a common ancestral clone in individual clusters independently.

Before the war diphtheria, measles, tuberculosis and whooping cough were the most important of the better-defined causes of death amongst young children in the London area. The large numbers of deaths registered from these four diseases in the age group 0–4 years in the Metropolitan Boroughs alone between 1931 and 1938, together with the deaths recorded under bronchitis and pneumonia, are set out in Table 1.

1. The authors concluded in a previous paper that the most reliable single test for the detection of Bact. coli was incubation in MacConkey's broth at 44° C, such a test for Bact. coli alone being necessary in shellfish because of occasional multiplication of other coliforms in purified mussels. The present investigation is an attempt to verify this finding on a broader basis.

2. A description is given of the isolation of 1600 cultures of coliform organisms from polluted mussels, sewage, and faeces (human, cow, sheep and sea birds). Their classification according to ‘IMViC’ reactions and the production of gas in MacConkey's broth at temperatures of 37, 41, 44, 45 and 46° C. is given.

3. Of the + + − − type, 1036 out of 1065 cultures (97·3%) were found to produce gas in MacConkey's broth at 44° C. A balance is noted between the + + − − type which does not produce gas at 44° C. (irregular I) and the two irregular types which do so (irregular II and irregular VI). Such a balance was reported by Bardsley (1938).

4. From the cultures examined it is confirmed that incubation at 44° C. is the most suitable temperature for use with MacConkey's broth for permitting the maximum number of Bact. coli to produce gas while inhibiting the maximum number of other coliforms.

Fifty-seven bacterial isolates previously identified as Bordetella avium or B. hinzii were characterized by restriction enzyme analysis (REA) and/or ribotyping. Twenty restriction endonucleases were evaluated for REA. Digestion of chromosomal DNA from the 42 B. avium and 15 B. hinzii isolates with Hinf I produced 8 and 7 distinct fingerprint profiles, respectively. Digestion with DdeI further discriminated these Bordetella species and produced 12 fingerprint profiles for B. avium and 4 profiles of B. hinzii. In addition, B. avium isolates were clearly distinguishable from B. hinzii isolates by ribotyping with the restriction endonuclease PvuII. The ribotype patterns of these two species of Bordetella were unique when compared to previously reported ribotype patterns for B. bronchiseptica isolates. Since it was possible to discern differences among isolates within each Bordetella species by REA analysis, we suggest that REA could be used in developing a typing system based on the fingerprint profiles generated.

The object of this paper is to describe the immunizing procedures that have proved to be the most suitable up to the present time for preparing a potent serum from the horse for the treatment of typhoid fever. The principles on which the methods are based have their origin in the studies of Felix and his collaborators on the antigenic structure of Salmonella typhi. The technical details that follow will, we hope, assist those who are interested in the preparation of the serum as a therapeutic agent to obtain products which maintain a consistently high level of potency. This objective is not readily attained, but is of paramount importance, because the clinical use of products that fall below the permissible limits of potency would tend to bring discredit upon the serum as a specific remedy owing to insufficient dosage. The adoption of standards of potency that are prescribed by an official authority is an obvious desideratum and would guard against this risk, but in the meantime we shall be pleased to help by providing the requisite cultures and serological reagents.

Leptospirosis is the most widespread zoonosis in humans worldwide. In the United States, widespread detection of antibodies to leptospirosis have been identified in feral swine (Sus scrofa) with the highest detection of serovars, Bratislava, Icterohaemorrhagiae, and Pomona. Over the past few years, feral swine populations have expanded their geographical range and distribution in the United States with reports in at least 39 of 50 states. Since feral swine serve as reservoirs for serovars that can infect humans, it is important to understand the risk of transmission. In order to learn more about the probability that feral swine shed infectious leptospires, we collected kidneys and paired serum when possible from 677 feral swine in 124 counties of 29 states. These counties had previously been identified as antibody positive for Leptospira interrogans serovars Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae or Pomona. Although exposure to these same six serovars of leptospirosis continued to be high (53% overall) in the counties we sampled, we detected leptospiral DNA in only 3·4% of feral swine kidneys tested. Based on these results, it appears that although feral swine can serve as a source of infection to humans, especially in those who are more likely to encounter them directly such as wildlife biologists, veterinarians, and hunters, the risk may be relatively low. However, further studies to examine the relationship between leptospiral shedding in the urine and kidneys in addition to culturing the organism are recommended in order to better understand the risk associated with feral swine.

Enhanced surveillance for Hib infection, initially covering Wales and five English regions, began in 1990 and in 1995 was extended to the whole of England and Wales. To determine whether changes in the ascertainment of Haemophilus influenzae may have affected estimates of Hib disease incidence, data from January 1990 to December 2003 were analysed. A total of 8887 and 4020 (45%) cases of H. influenzae and Hib respectively were reported. The proportion of isolates that were serotyped increased over time, and therefore reported incidence may have underestimated the true incidence in the early years of the study. Adjusting for this under-ascertainment, the incidence in children aged <5 years declined from a peak of 28·3/100 000 in 1991 to 0·97/100 000 in 1998 and increased to 3·8/100 000 in 2003. Following the implementation of universal vaccination a dramatic decline in the true incidence of invasive Hib disease occurred. The observation of the subsequent resurgence was real but the highest incidence reached was 85% below the corrected incidence in the pre-vaccine era. Continued high-quality surveillance is needed in order to accurately monitor and detect changes in disease incidence.

During the 11-year period from 1997 to 2007, 321 isolates of Listeria monocytogenes from sporadic cases of invasive listeriosis were reported to the national reference laboratory in Israel. Of these isolates, 113 (35%) were identified from perinatal cases, and 208 (65%) from non-perinatal cases. The prevalent serovars were 4b, 1/2b, 1/2a and 4c. Serovar 4b was identified in 80·5% of the perinatal isolates (P=0·0162), while the number of 1/2b and 1/2a strains increased in the ⩾60 years old group (P=0·0285). Resistance to tetracycline was found in eight 4b isolates. The seasonal distribution showed that 206 isolates (64·2%) were submitted during the hot season (May–October). The estimated morbidity for the study period was 4·4 per million. The incidence of invasive listeriosis was higher in the perinatal group (5·6/100 000), than in individuals aged ⩾60 years (1·5/100 000).

This study investigated individual and contextual factors associated with the duration of diarrhoeal episodes in 693 young children living in a large Brazilian city who were followed-up for at least 3 months. The outcome is analysed as a continuous variable, by means of a hierarchical conceptual model organizing the factors in meaningful blocks. A total of 2397 episodes were recorded (median duration 2 days, interquartile range 1–3 days). Low percentage of households connected to the sewerage system in the neighbourhood, low family purchasing power, high agglomeration, mother aged <19 years, low zinc content in child's diet, and episode severity were significantly associated with longer duration (0·26–0·69 days more). Purchasing power effect was largely mediated by environmental conditions, characteristics of the child, and hygienic behaviour. Environmental conditions acted as a possible effect modifier, enhancing the effect on duration of diarrhoea of the child not having being vaccinated against measles or breastfed for >6 months.

In discussing a case of meningitis caused by B. paratyphosus B, Brahdy (1925) calls attention to the extreme rarity of such a condition. An exhaustive survey of the literature led Brahdy to the discovery of only eight cases of paratyphoid meningitis, these being recorded by French or German observers.

The efficacy of interferon A (rIFN-α2A), an Escherichia coli-derived interferon, in the prophylaxis of acute upper respiratory tract infection, was evaluated in a community-based double-blind placebo-controlled study in the Australian winter of 1985. The trial population of 412 healthy volunteers (190 males and 222 females, aged 18–65 years) self-administered 1·5, 3·0 and 6·0 megaunits (MU) of interferon A per day or a placebo, intranasally for 28 days.

The period of study coincided with an outbreak of H3N2 influenza A (detected in 35 of the 107 acute specimens) as well as substantial numbers of respiratory syncytial virus and adenovirus infections. Rhinoviruses were isolated from only three specimens. In many cases, subjects had laboratory and clinical evidence of having had more than one respiratory tract infection during the period of the study. Viruses were detected in 54 or 107 acute specimens (49%).

No statistically significant differences were noted between the various treatment groups in the incidence of laboratory-proven viral infection (virus isolation and/or antibody response). Analysis of reported symptoms indicated that blood-tinged mucus and nasal stuffiness occurred more frequently with higher doses of interferon. There appeared to be no clinical benefit from the use of interferon A in the amelioration of symptoms.

A single application of the male chemosterilant, α-chlorhydrin, to a problem sewer rat infestation resulted in reductions of rat numbers and distribution which was comparable to effects of warfarin baiting methods. Rat numbers were reduced by more than 85% by both methods. More rapid mortality and recruitment were evident for warfarin effects; the α-chlorhydrin treated population had a longer lag phase of growth so that reinfestation of sewer habitat to pre-treatment numbers, and distribution over a 40 square block area, required approximately 1·5–2 times longer after α-chlorhydrin treatment when compared with warfarin treatment. Comparisons of changes in rat densities in infested sewers following the two treatments indicate that recovery of warfarin treated populations is achieved by reproductive recruitment followed by dispersal while α-chlorhydrin treated populations recover by slower immigration and later reproductive recruitment. Alpha-chlorohydrin should be a useful addition to a limited arsenal of rat control agents because of its specificity for the Norway rat, its single dose effectiveness as a toxicant-chemosterilant, and its short environmental half-life.

We examined pertussis hospitalizations among infants aged <1 year between 2006 and 2008 using the nationwide inpatient database in Japan. A total of 660 infants hospitalized for pertussis were identified. Peak incidence occurred at age 1 month and infants aged 0–2 months (too young for pertussis vaccination) and ⩾3 months (eligible for at least one dose of vaccination) accounted for 44·5% and 55·5% of hospitalizations, respectively. Complications related to pertussis were found in 165 (25·0%) cases, including one death; the age at admission did not differ significantly between patients with and those without complications (mean age 4·1 vs. 4·5 months, P=0·12). Seventeen patients required mechanical ventilation. Of the 17 cases, 14 infants were aged <3 months and three infants were aged ⩾3 months. Our findings highlight that the vaccination schedule against pertussis may often be delayed in Japan.

In January, 1914, Dr J. H. Reford, Uganda Medical Staff, reported the discovery, in the blood of a dog belonging to a European missionary, of a trypanosome showing marked morphological resemblance to the human parasite, the so-called Trypanosome rhodesiense. The dog had made a single journey through the morsitans belt south of Masindi. It died after a short and severe illness characterised by marked emaciation and keratitis. Dr Reford recognised a certain number of trypanosomes in which the nucleus was displaced posteriorly, and also sundry irregular, more or less rounded-off forms. Miss Robertson, who had just completed a tour in this same fly belt, examined some of Dr Reford's slides and expressed her agreement with his view as to the affinities of the organism to the Rhodesian trypanosome. As she had not met with any trypanosomes of the gambiense-brucei group during her experiments in the same district, Miss Robertson, in a report to the Principal Medical Officer dated 20th January, 1914, laid considerable stress on the importance of the find and discussed at some length the pros and cons of the arrival of the dreaded South African organism in this already overburdened Protectorate.

We analysed nation-wide reported measles cases during the 1988–9 epidemic and found that longer duration and wider spread were two major characteristics of the outbreak. All the 22 county/city index cases were reported with a delay of > 4 days and 64% were aged 5–14 years. This epidemic occurred mainly among 5–14-year-old school-children (59%), infants under 1 year (19%), and pre-school children (18%). The overall attack rate was 0·63 cases per 10000 population, with the highest attack rate (7·4 cases per 10000 population) occurring in infants. Among 280 confirmed cases <15 months of age, 9-month-old infants (42 cases) had a higher risk of measles and peaked at 10 months (49 cases). This epidemic started in March 1988 among 5–9-year-old children in the northern suburban area, then spread to Taipei City and neighbouring counties or cities. It continued to spread from the northern to southern and western areas during the summer vacation and New Year holidays. Multiple logistic regression analysis showed that the delay of measles reporting was strongly associated with the cases infected early in the epidemic (OR= 6·9, P < 0·001) and reported from teaching hospitals (OR = 2·6, P < 0·001). The reappearance of high attack rates among 5–9-year-old children in the 1985 and 1988–9 measles epidemics in Taiwan indicated the persistence of pockets of susceptible individuals even after mass immunization.

Topical medicaments used by patients with diseases of the skin were examined for microbial contamination. Ps. aeruginosa was isolated from stock pots of a diluted emulsifying ointment used as a soap substitute in the bath. Cross-con tamination between patients and medicament was subsequently shown to have occurred.