The development of a Klebsiella serotyping method by counter-current immunoelectrophoresis (CIE) is described.

Antisera were prepared against the capsular antigens of 72 type strains and tested for the specificity and strength of their precipitin reactions with antigens from homologous and heterologous serotypes. All antisera produced strong reactions with their homologous antigen: when diluted to titre 63 were highly specific, 3 cross-reacted strongly and 6 weakly with one other antigen. Pools of antisera for screening purposes were constructed on the basis of common cross-reactions: component serotypes of each pool could be detected strongly and specifically.

The technique is simple to perform, fairly rapid, and economical in the use of antisera. Results can be read easily and quickly and the intensity of cross-reactions compared directly. The technique appears to be more specific and is less time consuming than the Quellung method, but further assessment of its efficacy in typing routine clinical cultures is necessary.

Campylobacter sp. is the most common cause of acute bacterial gastroenteritis in Sweden and the incidence has been increasing. Case-control studies to identify risk factors have been conducted in several countries, but much remains unexplained. The geographical distribution of campylobacter infections varies substantially, and many environmental factors may influence the observed pattern. Geographical Information Systems (GIS) offer an opportunity to use routinely available surveillance data to explore associations between potential environmental risk factors showing a geographical pattern and disease incidence, complementing traditional approaches for investigating risk factors for disease. We investigated associations between campylobacter incidence and environmental factors related to water and livestock in Sweden. Poisson regression was used to estimate the strength of the associations. Positive associations were found between campylobacter incidence and average water-pipe length per person, ruminant density, and a negative association with the percentage of the population receiving water from a public water supply. This indicates that drinking water and contamination from livestock may be important factors in explaining sporadic human campylobacteriosis in Sweden, and that contamination occurring in the water distribution system might be more important than previously considered.

A collection of 346 strains of Streptococcus milleri from a variety of human sources was examined culturally and biochemically, and for the presence of Lancefield group antigens. Most of the strains were non-haemolytic and ungroupable, but 25% were β haemolytic and 19% were α haemolytic; 28% possessed a group antigen (A, 5%; C, 6%, F, 14%, G, 3%). These antigens were present in 69% of β-haemolytic but in only 13% of α-haemolytic or non-haemolytic strains; β haemolysis occurred in 82% of group-F strains, 43% of other groupable strains and 11% of ungroupable strains.

The following reactions were given by > 80% of S. milleri strains: hydrolysis of arginine and aesculin, a positive Voges–Proskauer reaction, and acidification of trehalose, lactose, salicin and sucrose. A minority of strains showed enhancement of growth by CO2, bile tolerance, NaCl tolerance, and ability to acidify other sugars, notably mannitol, raffinose and melibiose. Departures from the modal pattern of biochemical reactions showed a weak correlation with the type of haemolysis and the presence or absence of a group antigen but were not sufficiently systematic for clear-cut subdivisions to be recognized within the species.

S. milleri therefore appeared to comprise a ‘central’ group of non-haemolytic strains that rarely formed a Lancefield-group antigen, in which the aesculin reaction was nearly always positive, lactose was usually acidified, and a considerable minority showed enhancement of growth by CO2 and bile tolerance. Deviations from this pattern were of two main types. (1) ‘Loss’ of one or more of these reactions, which tended to be associated with β-haemolysis and presence of a group antigen. In these respects, α-haemolytic strains tended to occupy an intermediate position. (2) ‘Gain’ of the ability to acidify additional sugars, notably raffinose and melibiose or mannitol; this occurred mainly among otherwise typical non-haemolytic strains that were rarely groupable.

Only 12% of isolations from the bloodstream of patients suffering from systemic infections were β haemolytic and only 18% possessed a group antigen, but a considerably greater proportion of those from visceral abscesses were β haemolytic (28%). Among isolations from superficial lesions in some body sites there were considerably greater proportions of β-haemolytic and groupable strains; thus, nearly one-half of those isolated from the abdomen other than the female genital tract were β-haemolytic and over one-half were groupable. On the other hand, strains from the teeth and gums were nearly always non-haemolytic and ungroupable, and most vaginal isolations were of non-haemolytic strains with a wide sugar-fermentation pattern.

It has been shown that it is possible to investigate the colonization resistance in individual mice by determining the concentration of a certain contaminant (S.R.-E. coli) in the faeces during the first 4 days after contamination. Experimental contamination is contra-indicated in many cases such as in individuals with decreased resistance to infection. Particularly in this group, the value of the colonization resistance should be determined. It appeared to be possible to determine the colonization resistance in such individuals by quantitative biotyping of the Enterobacteriaceae species in the faeces on several consecutive days.

Forty ponies immunized with inactivated virus vaccine containing A/equine/Miami/63 (H3N8) virus and six unvaccinated, seronegative ponies were experimentally challenged with a representative of recent equine H3N8 virus isolates, A/equine/Newmarket/79. All unvaccinated ponies became infected as judged by virus excretion, febrile responses and antibody responses, but only two of the vaccinated ponies were fully protected. Pre-challenge antibody levels to A/Newmarket/79 virus detected by single radial haemolysis (SRH) correlated well with the degree of clinical protection but the levels required for complete protection (SRH zones > 65 mm2) were high. The importance of these results in relation to conventional vaccination procedures against equine influenza is discussed.

Post-infectious irritable bowel syndrome (PI-IBS) has been established as a sequel of infectious intestinal disease (IID). The aim of this study was to estimate the burden of PI-IBS caused by the pathogens Campylobacter, Salmonella and Shigella, and to compare this with other outcomes associated with these pathogens. The attributable risk of PI-IBS due to bacterial pathogens was calculated and linked to national data on gastroenteritis incidence and measures for severity and duration of illness in order to estimate the burden of PI-IBS. One year post-infection, IBS developed in 9% of patients with bacterial IID. The burden of PI-IBS adds over 2300 disability adjusted life years to the total annual disease burden for the selected pathogens. PI-IBS is a frequent sequel of IID, resulting in a considerable disease burden compared to other outcomes. If this relationship is not considered, this will result in an underestimation of the disease burden of IID.

Forty-one newly sequenced isolates of Arctic and Arctic-like rabies viruses, were genetically compared to each other and to those available from GenBank. Four phylogenetic lineages of Arctic viruses were identified. Arctic-1 viruses circulate in Ontario, Arctic-2 viruses circulate in Siberia and Alaska, Arctic-3 viruses circulate circumpolarly, and a newly described lineage Arctic-4 circulates locally in Alaska. The oldest available isolates from Siberia (between 1950 and 1960) belong to the Arctic-2 and Arctic-3 lineages and share 98·6–99·2% N gene identity with contemporary viruses. Two lineages of Arctic-like viruses were identified in southern Asia and the Middle East (Arctic-like-1) and eastern Asia (Arctic-like-2). A time-scaled tree demonstrates that the time of the most recent common ancestor (TMRCA) of Arctic and Arctic-like viruses is dated between 1255 and 1786. Evolution of the Arctic viruses has occurred through a northerly spread. The Arctic-like-2 lineage diverged first, whereas Arctic viruses share a TMRCA with Arctic-like-1 viruses.

Foot and mouth disease (FMD) is a major animal health problem within Southeast Asia (SEA). Although Indonesia and more recently the Philippines have achieved freedom from FMD, the disease remains endemic on continental SEA. Control of FMD within SEA would increase access to markets in more developed economies and reduce lost productivity in smallholder and emerging commercial farmer settings. However, despite many years of vaccination by individual countries, numerous factors have prevented the successful control of FMD within the region, including unregulated ‘informal’ transboundary movement of livestock and their products, difficulties implementing vaccination programmes, emergence of new virus topotypes and lineages, low-level technical capacity and biosecurity at national levels, limited farmer knowledge on FMD disease recognition, failure of timely outbreak reporting and response, and limitations in national and international FMD control programmes. This paper examines the published research of FMD in the SEA region, reviewing the history, virology, epidemiology and control programmes and identifies future opportunities for FMD research aimed at the eventual eradication of FMD from the region.

Since new vaccines and anti-viral drugs for influenza have become available, collation of actual and country-specific epidemiological data is essential. Since respiratory syncytial virus (RSV) is a well known paediatric airway pathogen and some epidemiological data exist already, a comparison between influenza and RSV seems warranted. From July 1996 to June 2001 the naso-pharyngeal aspirates (NPA) of children from birth to 16 years of age, admitted to one of the two paediatric hospitals in Kiel, Germany, were investigated by a nine-valent multiplex reverse transcriptase PCR assay. NPA were investigated in 60·8% of 3469 children admitted with an acute respiratory tract infection. Community-acquired or nosocomial infections (in parentheses) due to influenza A were diagnosed in 122 (10) children, due to influenza B in 14 (2) and due to RSV in 325 (24) cases. Patients with influenza A (median 752 days) and influenza B (median 966 days) were older than patients with RSV (median 168 days). The spectrum of disease presentation was broader in influenza than in RSV. In each winter, admissions with influenza were less common than those with RSV. Influenza B only occurred in 2 of the 5 years. The cumulative, population-based incidences per 100 000 children 0–16 (0–5, >5–16) years of age were 53 (123, 22) for influenza A, 16 (30, 9) for influenza B and 165 (453, 4) for RSV. Cardiac conditions and asthma were the major risk factors for admission to hospital with influenza A (RR 9·8, 4·1) and RSV (8·5, 2·1) infections. Underlying conditions were most common in influenza B. Low gestational age doubled the risk for admission to hospital with influenza A infection, but did not show a dose–effect relationship as in RSV. The burden of influenza-positive hospitalizations was about one third that of RSV. The incidence was similar to reports from the United States. Targeting children with underlying conditions, especially cardiac conditions and asthma in the German immunization programme is appropriate, as long as no policy for vaccination of the general paediatric population exists.

Campylobacter is the most common known source of human bacterial enteritis in the developed world and poultry is considered the main source. Broilers often become colonized with Campylobacter during rearing, and then contaminate the farm environment. The objective of this study was to identify Campylobacter-positive environmental reservoirs on farms, as these pose a risk to broiler flocks becoming colonized with Campylobacter. We considered the temporal aspects of exposure and colonization. A longitudinal study monitored six conventional rearing farms over 2 years. The broiler flocks, catchers' equipment, vehicles, shed surrounds, shed entrance, other equipment, farm entrance, other animals, puddles, dead birds, mains water and drinkers were systematically sampled 2–4 times per flock. A multivariable generalized estimating equation model was used to assess associations between contaminated environmental sites and colonized broiler flocks. The associations were adjusted for confounders and other known risk factors. To further assess temporality of contamination, the sequence of contamination of the different environmental sites and the flocks was established. Contaminated shed entrances and anterooms, contaminated drinkers and shedding of Campylobacter by other animals such as cattle, dogs, wildlife and rodents were significantly associated with positive flocks. The reservoir of ‘other animals’ was also the reservoir most commonly positive before the flock became colonized. The other sites usually became contaminated after the flock was colonized.

1. The basic observations of Piekarski (1937–40) and F. Neumann (1941) on Feulgen-positive, chromatinic structures, going through a regular cycle of division, in the cells of Bact. coli and Proteus vulgaris are confirmed and the view that these structures are nuclear in nature is accepted.

2. The chromatinic structures in bacteria from old cultures, although usually distinguishable from the cytoplasm, are too small to be resolved accurately. After transfer to a fresh nutrient medium the chromatinic structures increase in size and give rise to short, often dumbbell shaped, rods (chromosomes) which multiply by splitting lengthwise in a plane more or less parallel with the short axes of the bacterium.

3. The chromatinic structures of Bacl. coli and of Proteus vulgaris are essentially the same as those previously described in myxobacteria and actinomycetes (Badian, 1930, 1933, 1936) and in various well-known aerobic spore-forming bacteria (Badian, 1933, 1935; Robinow, 1942).

4. A single cell of Bact. coli or Proteus vulgaris contains one chromatinic body or one or two pairs of these, representing primary and secondary division products.

5. Few bacteria from young cultures are single cells. When fixed through the agar with Bouin's mixture and stained briefly with Giemsa's solution, bacteria from young growing cultures of Bact. coli, Proteus vulgaris, B. mesentericus and B. megatherium assume a banded appearance indicating that each bacterium consists of two, three or four separate cells.

6. A plasmolysing treatment has been applied to B. megatherium which provides direct proof of the composite structure of this bacillus by inducing its component protoplasts to shrink away independently from the outer supporting cell wall.

I wish sincerely to thank Dr H. B. Fell for the hospitality offered to me at the Strangeways Laboratory, for her sustained interest in this investigation and for her help in preparing the manuscript for the press. I have also pleasure in admitting my indebtedness to Prof. E. G. Pringsheim for much helpful criticism and advice in matters relating to the bacterial cell wall.

In 1999–2000 we conducted a one-year, retrospective population-based survey in Norway to estimate the incidence of gastroenteritis and study the association with selected exposures. A self-administered questionnaire was mailed to 3000 persons selected at random from the population registry, with 250 persons being contacted each month. The response rate was 61%. The incidence of acute gastroenteritis was 1·2 per person-year. The incidence was higher for women than for men. Of the total of 171 cases, 29 (17%) consulted a physician, 13 (8%) reported that a stool sample was taken, and 7 (4%) were admitted to hospital. Among children aged less than 15 years, drinking water from a private water supply was associated with illness, while using chlorinated water was protective. Among adults aged 20–40 years, travelling abroad was associated with illness. The incidence in our survey is similar to rates found by FoodNet in United States.

The epidemiology of notified cases of campylobacter gastroenteritis in adults in Nottingham Health District was investigated using a case-control study with a postal questionnaire to ascertain data on risk factors. Over a 14-month period 531 cases (a 73% response rate of all laboratory confirmed cases) and 512 controls replied.

Conditional logistic regression analysis was used to determine independent associations with infection. These included foreign travel (odds ratio (OR) 3·4; 95% confidence intervals (CI) 2·0–5·7), diabetes mellitus (OR 4·1, CI 1·1–17), medication with omeprazole (OR 3·5, CI 1·1–12) and H2 and H2 antagonists (OR 3·7, CI 1·3–15), contact with puppies (OR11·3, CI1·2–105), eating chicken (OR 1·4, CI 1·1–1·8) and drinking milk from bottles with tops damaged by a bird (OR 3·3, CI 1·0–11). Preparing main meals (OR 0·9, CI 0·8–1·0) and drinking delivered milk (OR 0·6, CI 0·4–0·9) were associated with a reduced risk of campylobacter infection.

Foreign travel was reported in 25% of cases and another 15% had significant associations with other risk factors. The majority of cases, 60%, remained unexplained, indicating the need for further evolution of sporadic cases.

1. A study of the freely chosen diets of sixty-three men of the English middle class has been made by the “individual” method. All food was weighed for the period of a week, and the amounts of protein, animal protein, fat, carbohydrate, calories, calcium, total and available phosphorus and total and available iron in the individual diets have been calculated. Detailed and averaged results for the diets are given.

2. The average calorie intake was 3067 per day, but a very wide variation was observed (1772–4955 calories), and it is suggested that the adoption of 3000 calories as the requirement of an individual man may be most misleading.

3. There was a definite, but mathematically insignificant, decrease in calorie intake with increasing age. The individual variation at each age was so great, however, that no rules for the guidance of individuals as to their dietary requirements at different ages can possibly be formulated.

4. No significant correlation existed between calorie intake and body weight.

5. The proportion of calories derived from fat was higher than any figures previously recorded in this country. The proportion of calories derived from carbohydrate was correspondingly lower.

6. The total calcium, phosphorus and iron intakes were 0·87 g., 1·61 g. and 16·8 mg. per day respectively. 98 per cent, of the total phosphorus eaten was in an “available” form, while only 66 per cent, of the iron could be considered to be physiologically available.

7. A similar study has been carried out on six unemployed men, and the chemical composition of these diets is compared with that of employed, middle-class individuals.

Acknowledgments. The author wishes to thank Dr R. A. McCance for his enthusiastic encouragement and help, Miss M. Verdon-Roe for her assistance with the calculations, and all the subjects of the investigation for their willing co-operation. Part of the expense of this investigation were defrayed by a personal grant from the Medical Research Council.

Infections due to Salmonella enteritidis are increasing worldwide. In the United States, between 1985 and 1989. 78% of the S. enteritidis outbreaks in which a food vehicle was identified implicated a food containing raw or lightly cooked shell eggs.

Under a US Department of Agriculture regulation published in 1990, eggs implicated in human food-borne S. enteritidis outbreaks were traced back to the source flock. The flock environment and the internal organs of a sample of hens were tested for S. enteritidis. We compared the S. enteritidis phage types of isolates from 18 human, egg-associated outbreaks and the 15 flocks implicated through traceback of these outbreaks. The predominant human outbreak phage type was recovered from the environment in 100% of implicated flocks and from the internal organs of hens in 88% of implicated flocks we tested. The results support the use of phage typing as a tool to identify flocks involved in human S. enteritidis outbreaks.

In September 2000 an outbreak of influenza-like illness was reported on a cruise ship sailing between Sydney and Noumea with over 1100 passengers and 400 crew on board. Laboratory testing of passengers and crew indicated that both influenza A and B had been circulating on the ship. The cruise coincided with the peak influenza period in Sydney. Morbidity was high with 40 passengers hospitalized, two of whom died. A questionnaire was sent to passengers 3 weeks after the cruise and 836 of 1119 (75%) responded. A total of 310 passengers (37%) reported suffering from an influenza-like illness (defined as cough, fever, myalgia and weakness) and 528 (63%) had seen a doctor for illness related to the cruise. One-third of passengers reported receipt of influenza vaccination in 2000; however neither their rates of influenza-like illness nor hospitalization were significantly different from those in unvaccinated passengers. A case–control study also found no significant protective effect of influenza vaccination. With the increasing popularity of cruise vacations, such outbreaks are likely to affect increasing numbers of people. Whilst influenza vaccination of passengers and crew may afford some protection, uptake and effectiveness may not be sufficient to prevent outbreaks. Surveillance systems and early intervention measures, such as antiviral therapies, should be considered to detect and control such outbreaks.

In the 15 months, February 1976 to April 1977, more than 241 patients became colonized with a strain of Klebsiella aerogenes, capsular serotype K2, resistant to most antibiotics. Urinary tract infection was the most common clinical manifestation but bacteraemia and, occasionally, infections of other sites were encountered. The main reservoir of the epidemic klebsiella was the gut, urine and skin of colonized patients. Gut carriage among staff was very uncommon. The most susceptible patients were elderly males, with debilitating illnesses and urinary tract abnormalities, especially if they were catheterized or receiving antibiotics. Likely vehicles for spread were the hands of staff, and contaminated bedpans and urinals. Control measures were directed at these factors. At the end of April 1977 no new cases had occurred for 3 months in the ward in which the outbreak began, and which had been the main focus of infection, and only 5 patients in the affected hospitals were known to be colonized by the epidemic klebsiella.

A quantitative risk assessment model investigating the risk of human infection with campylobacter from the consumption of chicken meat/products is currently being formulated. Here such an approach is used to evaluate the probability that a random bird, selected at slaughter from Great Britain's national poultry flock, will be campylobacter-positive. This is determined from the probability that a flock chosen at random contains at least one colonized bird and the within-flock prevalence of such a flock at slaughter. The model indicates that the probability bird chosen at random being campylobacter-positive at slaughter is 0·53. This probability value has associated uncertainty, the 5th percentile being 0·51 and the 95th percentile 0·55. The model predicts that delaying the age at first exposure to campylobacter can have a significant impact on reducing the probability of a bird being campylobacter-positive at slaughter. However, implementation of current biosecurity methods makes this difficult to achieve.

Serpulina pilosicoli was isolated from 8 of 43 (19%) faecal specimens obtained from feral waterbirds sampled around a small lake at Perth Zoological Gardens, Western Australia, and from 3 of 7 (43%) samples of the lake water. The organism was only isolated from 1 of 204 (0·5%) samples from captive birds and animals in the zoological collection. Multilocus enzyme electrophoresis analysis of the isolates showed that they were genetically diverse, and none had identical electrophoretic profiles as those previously obtained from human beings, dogs, pigs and other avian species. To determine the survival time of S. pilosicoli in water, cells of strain 1648 were seeded into lake and tap water, and incubated at 4, 25 and 37°C. The organism could be recultured from lake water for up to 66 days at 4°C, and for 4 days at 25°C. A healthy human volunteer who drank water seeded with S. pilosicoli strain Wes B became colonized, and developed abdominal discomfort and headaches. Contamination of water by faeces may represent a source of S. pilosicoli infection for both humans and animals.

1. Antisera prepared in rabbits or calves against live Salmonella dublin gave mice some degree of protection against oral infection with this organism. Both antiserum prepared against heat-killed S. dublin and dead vaccines prepared in a variety of ways produced little or no immunity.

2. A rough variant of S. dublin of low virulence for mice, no. 17 A, produced a reasonably good immunity against oral infection with S. dublin in mice but not in calves. Mice that survived injection with another rough variant that possessed a considerable degree of virulence for these animals, no. 51, were immune to oral infection with S. dublin. Experimentally and naturally, this variant and, to a lesser extent, 9S, a smooth variant of S. gallinarum of reduced virulence, produced an appreciable degree of immunity in calves against S. dublin infection; none of the calves injected with these variants showed any signs of ill-health as a result.

3. Two rough variants of S. cholerae-suis, nos. 3 and 6, possessed a considerable degree of virulence for mice; those that survived were resistant to oral infection with S. cholerae-suis. Experimentally and naturally, both variants produced an appreciable degree of immunity in pigs.

4. Mice that survived vaccination with the rough S. cholerae-suis variant no. 6 were resistant to oral infection with S. dublin. Those that survived vaccination with the rough S. dublin variant no. 51 were resistant to oral infection with S. cholerae-suis and S. typhi-murium; they were fully susceptible to parenteral administration of Escherichia coli and Erysipelothrix rhusiopathiae.

5. Vaccination with S. cholerae-suis variants 3 and 6 and S. dublin variant 51 provoked the formation of H but not O antibodies. These variants were never found to mutate from rough to smooth in vitro or in vivo.