Variation in the incidence of invasive pneumococcal disease across South and West England, in 1995, was measured through a survey of microbiology laboratories. A 100% response rate was achieved. The incidence by laboratory varied between 5·2 and 20·4 per 100000 catchment population (P<0·001). Adjusting for pneumococcal vaccine uptake rate in over 65 year olds, hospital admission rates, blood culture system used and for the age and sex structure of the population, did not account for this variation. When blood culture sampling rates were included in a logistic regression model, the variation between laboratories was much less and of lower statistical significance (P=0·019). Higher rates of blood culture sampling were associated with a higher incidence of invasive pneumococcal disease. Consistently high sampling should be encouraged because a higher diagnostic rate should result in more selective prescribing of antibiotics, and secondly because improved ascertainment of severe pneumococcal infections is a prerequisite for the evaluation of new pneumococcal conjugate vaccines.

Eight cases of Salmonella senftenberg infection in infants were identified in the first half of 1995 in England, five were indistinguishable S. senftenberg strains. A case-control study showed an association between illness and consumption of one brand of baby cereal (P=0·03). The cereal manufacturer reported isolating S. senftenberg in June 1994 from an undistributed cereal batch. Outbreak strains and the cereal strain were all plasmid-free in contrast to other human isolates of S. senftenberg in the same period. Changes in the production process were implemented to prevent further contamination.

Surveillance centres should strengthen the detection and investigation of outbreaks of gastrointestinal infection in susceptible groups, especially young children. In this outbreak, the study of only five cases led to identification of the vehicle of infection. Even when few cases are reported, epidemiological investigation in conjunction with molecular typing may lead to public health action which prevents continuing or future outbreaks.

We conducted a study to evaluate risk factors for developing typhoid fever in a setting where the disease is endemic in Karachi, Pakistan. We enrolled 100 cases with blood culture-confirmed Salmonella typhi between July and October 1994 and 200 age-matched neighbourhood controls. Cases had a median age of 5·8 years. In a conditional logistic regression model, eating ice cream (Odds ratio [OR]=2·3; 95% confidence interval [CI] 1·2–4·2, attributable risk [AR]=36%), eating food from a roadside cabin during the summer months (OR=4·6, 95% CI 1·6–13·0; AR=18%), taking antimicrobials in the 2 weeks preceding the onset of symptoms (OR=5·7, 95% CI 2·3–13·9, AR=21%), and drinking water at the work-site (OR=44·0, 95% CI 2·8–680, AR=8%) were all independently associated with typhoid fever. There was no difference in the microbiological water quality of home drinking water between cases and controls. Typhoid fever in Karachi resulted from high-dose exposures from multiple sources with individual susceptibility increased by young age and prior antimicrobial use. Improving commercial food hygiene and decreasing unnecessary antimicrobial use would be expected to decrease the burden of typhoid fever.

In 1994, 171 (27%) of all positive blood cultures in our hospital were due to Acinetobacter species. Of these, 138 cultures were considered significant, 91 (66%) were community-acquired and 47 (34%) were nosocomial. Most acinetobacter bacteraemia in children [les ]1 year old was community-acquired, while nosocomial infection was more common in children >1 year old (P=0·01). Most children [les ]5 years old were severely malnourished. The incidence of bacteraemia was lowest during the post-monsoon to early winter months. Acinetobacter bacteraemia associated mortality was twice (16%) that of all other patients (7·7%, P < 0·0005) and accounted for 4·5% of all hospital deaths during the study period. Bacteraemia caused by Acinetobacter species is an important cause of morbidity and mortality among our patient population with diarrhoeal disease.

We assessed the quality of evidence for the use of erythromycin in preventing secondary transmission of pertussis to close contacts of primary cases. A literature search was undertaken and identified papers were reviewed critically. Thirteen original papers and 1 manuscript met the inclusion criteria for review (3 randomized controlled trials, 4 analytical studies and 7 descriptive studies). Evidence from both experimental and analytical studies showed little effect of the use of erythromycin in preventing secondary transmission. Its effect is at best modest when compared with the protection conferred by use of good quality whole cell vaccine. Three studies reported adverse events with erythromycin prophylaxis; these were mainly nausea, vomiting and abdominal pain. In countries where effective pertussis vaccines are in use, erythromycin use should be confined to close contacts of cases, particularly unimmunized children or partially immunized infants who would be most susceptible to the complications of pertussis, or adults who come into close contact with vulnerable children.

In 1990, to study regional prevalences and risk factors of Helicobacter pylori infection in healthy young adult males, sera were collected from a nationwide sample of 1659 males (mean age 20·7 years) at introduction into the Air Force School for military students in Caserta, Italy. An enzyme-linked immunosorbent assay was used to detect H. pylori specific immunoglobulin G antibodies. The observed overall seropositivity rate was 17·5% (95% CI 15·7–19·4). Prevalence was higher in southern Italy and in the Italian islands as compared with northern Italy and central Italy (21·3% vs. 9·5%). Multiple logistic regression analysis showed that residence in southern areas and islands was the strongest predictor of the likelihood of H. pylori seropositivity; number of siblings in the household was marginally associated; years of father's schooling was not a significant predictor. H. pylori positive subjects were more likely positive for antibodies to hepatitis A virus infection (anti-HAV) than those H. pylori negative (35·4% vs. 24·9%; Odds Ratio 1·7, 95% CI 1·3–2·2). Adjustment for the confounding effect of sociodemographic variables weakened this association (OR 1·3, 95% CI 1·0–1·7). These findings suggest that differences in environmental conditions rather than in socioeconomic status may have played the major role in the different spread of H. pylori infection across the country.

Restriction fragment length polymorphism (RFLP) was used for the differentiation of 80 Coxiella burnetii isolates derived from animals and humans in Europe, USA, Africa and Asia. After NotI restriction of total C. burnetii DNA and pulsed field gel electrophoresis (PFGE) 20 different restriction patterns were distinguished. The index of discrimination for this typing system was 0·86. Comparison and phylogenetic analysis of the different RFLP patterns revealed evolutionary relationships among groups that corresponded to the geographical origin of the isolates. This finding was confirmed by genetic mapping. No correlation between restriction group and virulence of isolates was detected.

The prevalence of canine and human rabies in Thailand has decreased significantly during the last decade. This has been associated with an increasing number of human post-exposure treatments. Educational efforts, mass vaccination of dogs and cats and the use of safe and effective vaccines have all made an impact. The proportion of fluorescent antibody positive dogs, among those examined for rabies averaged 54% indicating that rabies is still a major public health threat. Canine rabies vaccination is not usually performed in animals <3 months old. However, this study revealed that 14% of rabid dogs were <3 months old and 42% were [les ]6 months old. This is the age group most likely to interact with humans and other dogs. Our study also supports the World Health Organization's recommendation that observing suspected rabid dogs for 10 days is an adequate and safe practice.

The prevalence of sexually transmitted diseases (STD) among women visiting antenatal (ANC) and gynaecological clinics in Gondar, north-west Ethiopia, was investigated. Between April and August 1995, 728 women consented to enter the study. Prevalence rates were 5·9% (41/693) for chlamydial antigen in cervix, 18·8% (113/600) for syphilis (Treponema pallidum haemagglutination assay [TPHA]) and 25·3% (150/593) for HIV. Active syphilis (RPR)+, TPHA+ was detected in 7·4% (44/597). HIV infection rate was higher among women with higher age of first marriage and low gravidity. It was significantly associated with young age, urban residence, and presence of genital ulcer (odds ratio [OR]=6·3), and lymphadenopathy (OR=2·8) on examination. Women seropositive for syphilis had married at an earlier age, were significantly older and had changed husbands. Low gravidity and age <30 were independently significant risk factors for cervical chlamydial antigen positivity which was predominantly asymptomatic. Significant association was observed between HIV infection and syphilis (OR=2·6). Active syphilis was associated with chlamydial (OR=3·4) and HIV infection (OR=4·1). The rate of 23·4% and 15·1% of HIV seropositivity among ANC attenders and rural women respectively is an indicator of the rapid progression of the HIV epidemic in the area.

A seroepidemiologic study of herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) was performed on Japanese adults. Serum samples collected between 1985–9 from a total of 536 healthy adults, female prostitutes, males with sexually transmitted diseases (STD), homosexual men, and pregnant women were studied by immunodot assays using HSV type-specific antigens, glycoproteins G (gG1 and gG2). HSV-1 infections correlated mostly with age and was widely prevalent among subjects <40 years. HSV-2 prevalence varied greatly among subgroups defined by sexual activity and was associated with risk behaviours for prostitution, infection with STD, and homosexual activity. HSV-2 seroprevalence was highest among prostitutes (80%), lowest among pregnant women (7 %), and intermediate in STD patients (23%) and homosexuals (24%). Because HSV-1 infection during childhood has been decreasing, primary genital HSV-2 infection, with its higher frequency of clinical manifestations, will become a greater burden to the public health in Japan.

A survey of beef carcases in abattoirs in the UK was carried out in order to estimate the prevalence of contamination with verocytotoxin – producing Escherichia coli (VTEC) serogroup O157. Contamination with verocytotoxin-producing E. coli (VTEC) O157 was confirmed in 0·47% of the 4067 (95% confidence limits 0·22–1·00%) of neck muscle samples. A significant tendency for carcases present in the same abattoir on the same day to have similar results was found, thus suggesting cross contamination.

VTEC O157 was found in 0·83% of 6495 bovine faeces samples routinely submitted for diagnostic purposes to Veterinary Investigation Centres in England and Wales. Of the samples from cattle less than 6 months old, 3·7% of 68 samples from animals without gastrointestinal disease were positive for E. coli O157, in contrast to 0·75% of 2321 samples from cases of gastrointestinal disease. No association with season or herd type (beef or dairy) was found.

During a survey of foal diarrhoea between 1991 and 1994, Clostridium perfringens was significantly associated with disease with 56% of cases infected [1]. The contribution of enterotoxigenic C. perfringens to this association, was assessed by use of the reverse passive latex agglutination test for enterotoxin (RPLA; Oxoid Unipath) and vero cell toxicity neutralized by antitoxin on stored faecal samples and sporulated faecal isolates of C. perfringens. Polymerase chain reaction (PCR1) based on the DNA sequence for the whole enterotoxin gene [2] yielded a fragment from an equine isolate of the anticipated size which, cloned into plasmid M13 phage, had a sequence essentially identical to the published sequence. Consequently, all faecal isolates were also tested by PCR1 and for a part of the enterotoxin gene (PCR2).

Significant association with diarrhoea (controls not in contact with cases) was found with positive RPLA tests on faeces (OR=13, P=0·002) and isolates (OR=4·57, P=<0·0001), vero cell toxicity of isolates (OR=1·78, P=0·026), and PCR1 (OR=nd, P=0·029) but not PCR2 or vero cell toxicity of faeces. Significant association with diarrhoea was also found for isolates negative by RPLA (OR=3·91; CI 2·05–7·57; P<0·0001) or PCR1 (OR=4·81; CI 2·84–8·20; P<0·0001). Many of the isolates from RPLA positive faeces and verotoxic isolates were PCR negative and no evidence could be found for the presence of the enterotoxin gene in a random selection of RPLA positive/PCR negative isolates by gene probe on chromosomal DNA and PCR reaction product or vero cell toxicity neutralized by specific antiserum. Failure of the vero cell toxicity on faeces to be associated with diarrhoea or for cytotoxicity of cultures and RPLA on cultures to agree with the PCRs was believed to be related to the presence of other cytotoxins, the inherent cytotoxicity of equine faeces and to the poor specificity of the commercial antiserum used in the test.

Enterotoxigenic C. perfringens could not account for the overall association of C. perfringens with foal diarrhoea because (a) cultures positive by PCR, RPLA or cytotoxicity were not significantly more common amongst isolates from cases than controls; and (b) the proportion of isolates from cases positive by PCR (PCR1 or PCR2) was too small at 9·7%.

A collection (164) of isolates of Bordetella bronchiseptica made predominantly from cats (132) but also from dogs (15), pigs (12) and other species was examined by pulsed field gel electrophoresis following macrorestriction digestion with XbaI. Each isolate was analysed twice and the patterns were entirely reproducible. The isolates fell into 17 different strains (>3 bands different) and within strains there were numerous subtypes. Feline isolates fell into 12 of the 17 strains. In general, cats housed together had similar or identical strains and subtypes of B. bronchiseptica. There was no difference in the PFGE patterns of isolates made from carrier cats and those from cats with respiratory disease. Isolates from pigs and dogs were in general similar to the feline isolates and there was no great evidence for species specificity. The PFGE pattern of feline and canine isolates were more related to whether the animals were housed together rather than whether they came from dogs or cats.