Showing papers in "Epidemiology and Infection in 1994"

The prevalence of Escherichia coli O157.H7 in dairy and beef cattle in Washington State.

Abstract: Escherichia coli O157.H7 was found in 10 of 3570 (0.28%) faecal samples from dairy cattle in 5 of 60 herds (8.3%). Several tentative associations with manure handling and feeding management practices on dairy farms were identified. Faecal/urine slurry samples, bulk milk samples, and milk filters from dairy herds were negative for E. coli O157.H7. E. coli O157.H7 was also isolated from 10 of 1412 (0.71%) faecal samples from pastured beef cattle in 4 of 25 (16%) herds. The prevalence of E. coli O157.H7 excretion in feedlot beef cattle was 2 of 600 (0.33%). The identification of cattle management practices associated with colonization of cattle by E. coli O157.H7 suggests the possibility that human E. coli O157.H7 exposure may be reduced by cattle management procedures.

Immunomagnetic separation as a sensitive method for isolating Escherichia coli O157 from food samples.

Abstract: Minced beef samples inoculated with Escherichia coli O157 were cultured in buffered peptone water supplemented with vancomycin, cefsulodin and cefixime (BPW-VCC) and subcultured to cefixime tellurite sorbitol MacConkey (CT-SMAC) agar both directly and after immunomagnetic separation (IMS) of the organism with magnetic beads coated with an antibody against E. coli O157 (Dynabeads anti-E. coli O157, Dynal, Oslo). E. coli O157 was recovered from initial inocula of 200 organisms/g by direct subculture and 2 organisms/g by IMS. Twelve strains of E. coli O157 of different combinations of phage type, H antigen and toxin genotype were all recovered from initial inocula of two organisms/g by IMS. Non-specific binding of other organisms to the magnetic beads could be reduced by washing of the beads in PBS with Tween-20 0.002-0.005% E. coli O157 was not bound by magnetic coated with an unrelated antibody. During investigation of a dairy herd that was possibly linked to a small outbreak of infection with E. coli O157, the organism was isolated from 2 of 279 forestream milk samples from individual cattle; both isolates were made only by the IMS technique. IMS is rapid, technically simple, and a specific method for isolation of E. coli O157 and will be useful in epidemiological studies.

The detection of antibodies against peste des petits ruminants virus in cattle, sheep and goats and the possible implications to rinderpest control programmes.

Abstract: Monoclonal antibody-based competitive ELISA (C-ELISA) have been used for the specific measurement of antibodies to both rinderpest and peste des petits ruminants (PPR) viruses in cattle, sheep and goats. Examination of serum samples from sheep and goats in Gambia, before and after vaccination with rinderpest vaccine, suggested that antibodies to PPR virus could prevent an immune response to the rinderpest vaccine. Cattle sera from Nigeria and Ghana showed a high prevalence of antibody against PPR virus which may explain the difficulty experienced in some countries in achieving high post-vaccination immunity levels against rinderpest. Because antibodies against PPR virus are both cross-neutralizing and cross-protective against rinderpest virus further vaccination in the presence of antibodies against PPR virus may be a waste of national resources. This paper presents serological evidence for the transmission of PPR virus from sheep and goats to cattle and highlights the need to include PPR serology in the sero-monitoring programme to give a better indication of national herd immunity.

Detection of mecA, femA , and femB genes in clinical strains of staphylococci using polymerase chain reaction

Abstract: MecA, a structural gene located on the chromosome of Staphylococcus aureus, characterizes methicillin-resistant S. aureus (MRSA), and femA and femB(fem) genes encode proteins which influence the level of methicillin resistance of S. aureus. In order to examine effectiveness of detecting mecA and fem genes in identification of MRSA, the presence of these genes in 237 clinically isolated strains of staphylococci was investigated by polymerase chain reaction (PCR). An amplified mecA DNA fragment of 533 base pairs (bp) was detected in 100% of oxacillin-resistant S. aureus, in 16.7% of oxacillin-sensitive S. aureus, in 81.5% of S. epidermidis, and in 58.3% of other coagulase-negative staphylococci (CNS). While the PCR product of femA (509 bp) or femB (651 bp) was obtained from almost all the S. aureus strains except for five oxacillin-resistant strains (2.5%), neither of these genes were detected in CNS. Therefore, the detection of femA and femB together with mecA by PCR was considered to be a more reliable indicator to identify MRSA by differentiating it from mecA-positive CNS than single detection of mecA.

Epidemic cholera in Ecuador: multidrug-resistance and transmission by water and seafood.

Abstract: To determine risk factors for cholera in an epidemic-disease area in South America, a case-control investigation was performed in Guayaquil, Ecuador, in July 1991. Residents > 5 years old who were hospitalized for treatment of acute, watery diarrhoea and two matched controls for each were interviewed regarding sources of water and food, and eating, drinking, and hygienic habits. Interviewers inspected homes of case-patients and controls to document water treatment, food-handling, and hygienic practices. Faecal specimens and shellfish were cultured for Vibrio cholerae O 1. Isolates were tested for susceptibility to a variety of antimicrobial agents. Drinking unboiled water (odds ratio [OR] = 4.0, confidence interval [CI] = 1.8-7.5), drinking a beverage from a street vendor (OR = 2.8, CI = 1.3-5.9), eating raw seafood (OR = 3.4, CI = 1.4-11.5), and eating cooked crab (OR = 5.1, CI = 1.4-19.2) were associated with illness. Always boiling drinking water at home (OR = 0.5, CI = 0.2-0.9) was protective against illness. The presence of soap in either the kitchen (OR = 0.3, CI = 0.2-0.8) or bathroom (OR = 0.4, CI = 0.2-0.9) at home was also protective. V. cholerae O 1 was recovered from a pooled sample of a bivalve mollusc and from 68% of stool samples from case-patients. Thirty-six percent of the isolates from stool specimens were resistant to multiple antimicrobial agents. Specific prevention measures may prevent transmission through these vehicles in the future. The appearance of antimicrobial resistance suggests the need for changes in current methods of prevention and treatment.

Sources of sporadic Yersinia enterocolitica infections in Norway: a prospective case-control study.

Abstract: Yersinia enterocolitica is a recognized cause of gastroenteritis in northern Europe. During October 1988-January 1990, a prospective case-control study was performed to address risk factors associated with sporadic Y. enterocolitica infections in southeastern Norway. Sixty-seven case-patients (mean age 23.4 years, range 8 months-88 years) and 132 age-, sex- and geographically-matched controls were enrolled in the study. Multivariate analysis of the data showed that persons with Y. enterocolitica infection reported having eaten significantly more pork items (3.79 v. 2.30 meals, P = 0.02) and sausage (2.84 v. 2.20 meals, P = 0.03) in the 2 weeks before illness onset than their matched controls; only one patient had eaten raw pork. Patients were also more likely than controls to report a preference for eating meat prepared raw or rare (47 v. 27%, P = 0.01), and to report drinking untreated water (39 v. 25%, P = 0.01) in the 2 weeks before illness onset. Each of these factors was independently associated with disease, suggesting a link between yersiniosis and consumption of undercooked pork and sausage products and untreated water. Efforts should be directed towards developing techniques to reduce Y. enterocolitica contamination of pork and educating consumers about (1) proper handling and preparation of pork items and (2) the hazards of drinking untreated water.

Estimated costs of postoperative wound infections. A case-control study of marginal hospital and social security costs.

Abstract: A cohort of 4515 surgical patients in ten selected intervention groups was followed. Three hundred and seventeen developed postoperative wound infections, and 291 of these cases were matched 1:1 to controls by operation, sex and age. In comparison to the controls the cases stayed longer in hospital after the intervention and had more contact after discharge with the social security system. Using data from a national sentinel reference database of the incidence of postoperative wound infections, and using national activity data, we established an empirical cost model based on the estimated marginal costs of hospital resources and social sick pay. It showed that the hospital resources spent on the ten groups, which represent half of the postoperative wound infections in Denmark, amounted to approximately 0.5% of the annual national hospital budget. This stratified model creates a better basis for selecting groups of operations which need priority in terms of preventive measures.

Smoking, the environment and meningococcal disease: a case control study

Abstract: This case control study investigated environmental factors in 74 confirmed cases of meningococcal disease (MD). In children aged under 5, passive smoking in the home (30 or more cigarettes daily) was associated with an odds ratio (OR) of 7.5 (95% confidence interval (CI) 1.46-38.66). ORs increased both with the numbers of cigarettes smoked and with the number of smokers in the household, suggesting a dose-response relationship. MD in this age group was also significantly associated with household overcrowding (more than 1.5 persons per room) (OR 6.0, 95% CI 1.10-32.8), with kisses on the mouth with 4 or more contacts in the previous 2 weeks (OR 2.46, 95% CI 1.09-5.56), with exposure to dust from plaster, brick or stone in the previous 2 weeks (OR 2.24, 95% CI 1.07-4.65); and with changes in residence (OR 3.0, 95% CI 1.0-8.99), marital arguments (OR 3.0, 95% CI 1.26-7.17) and legal disputes in the previous 6 months (OR 3.10, 95% CI 1.24-7.78). These associations were independent of social class. Public health measures to lower the prevalence of cigarette smoking by parents of young children may reduce the incidence of MD. The influence of building dust and stressful life events merits further investigation.

Sequence heterogeneity of the eae gene and detection of verotoxin-producing Escherichia coli using serotype-specific primers.

Abstract: The distribution of the Escherichia coli attaching and effacing (eae) gene in strains of verotoxin-producing E. coli (VTEC) isolated from cattle and humans was studied. The majority of strains isolated from humans with bloody diarrhoea or HUS and cattle with severe diarrhoea were eae positive (82 and 83% respectively). In contrast, 59% of VTEC isolated from asymptomatic cattle were eae negative and of the remaining 41% that were eae positive, the majority were serotype O157. H7. The nucleotide sequence of the 3' end of the eae gene of enteropathogenic E. coli (EPEC) of serotype O55. H7 was found to be almost identical to that of serotype O157. H7. Specific primers are described which detect the eae sequences of VTEC serotypes O157. H7, O157. H-, and EPEC serotypes O55. H7 and O55. H-. The nucleotide sequence of the 3' end of the eae gene of serotype O111. H8 differed significantly from that of O157. H7. Primers were developed to specifically identify the eae sequences of VTEC serotypes O111. H- and O111. H8. We conclude that whereas the majority of VTEC associated with disease in cattle and humans possess the eae gene, the gene itself may not be necessary to produce haemorrhagic colitis and HUS. Sequence heterogeneity in the 3' end of eae alleles of VTEC permits specific identification of subsets of these organisms.

Prevalence of human astrovirus serotypes in the Oxford region 1976-92, with evidence for two new serotypes.

Abstract: Results of serotyping on 291 astrovirus-positive stools collected between 1976 and 1992 showed that about two-thirds (64.9%) were serotype 1. Infections were more frequent in the fourth quarter of the year and there was a suggestion that during the past 5 years serotype 1 has occurred with greater frequency in alternate years. Evidence is provided for the existence of two new serotypes, 6 and 7.

Application of pulsed-field gel electrophoresis to the epidemiological characterization of Staphylococcus intermedius implicated in a food-related outbreak.

Abstract: An outbreak of food intoxication involving over 265 cases in western United States occurred in October 1991. Staphylococcus intermedius was implicated as the aetiologic agent. Representative outbreak isolates (five clinical and ten from foods) produced type A enterotoxin. DNA fragments generated by four restriction endonucleases and analysed by pulsed-field gel electrophoresis (PFGE) provided definitive evidence that all isolates from nine different counties in California and Nevada were derived from a single strain. The PFGE pattern of these outbreak isolates was distinct from those of a heterogeneous collection of seven S. intermedius strains of veterinary origin and five unrelated S. aureus laboratory strains. The data show a significant PFGE pattern heterogeneity not only among members of different Staphylococcus species but also within members of the same species and even the same enterotoxin type. The results indicate that PFGE is a valuable strain-specific discriminator for the epidemiological characterization of S. intermedius. To our knowledge, this represents the first documented foodborne outbreak caused by S. intermedius. These findings suggest that the presence of S. intermedius and other species such as S. hyicus in food should be reason for concern.

Contamination of hospital linen by Bacillus cereus.

Abstract: An investigation into two cases of post-operative Bacillus cereus meningitis revealed that hospital linen laundered by a batch continuous washing machine was heavily contaminated by B. cereus spores. The washing machine, detergents, other chemical additives and the water supply were eliminated as the source of contamination. It was found that the linen introduced into the washing machine had a high B. cereus spore content and that this was still present after the wash process. The spores were not killed by either the heat disinfection stage of the wash or the addition of chemical disinfectants and were not removed by the dilution in the process. The multiplication of B. cereus was thought to have occurred on used, damp linen stored in plastic bags, particularly when ambient temperatures were high. An increase in the water flow through the washing machine was the only measure associated with a decrease in B. cereus on laundered linen.

Contamination of hands and work surfaces with Salmonella enteritidis PT4 during the preparation of egg dishes.

Abstract: Salmonella enteritidis PT4 was recovered from fingers following the breaking of intact shell eggs artificially contaminated in the contents with the bacterium. Kitchen utensils used to mix egg dishes were salmonella-positive, sometimes after washing. Following the preparation of batter or the mixing of eggs, S. enteritidis was recovered from work surfaces over 40 cm from the mixing bowl. The bacterium survived well in thin, dry films of either batter or egg and, from an initial level of one cell per cm2, could be recovered from formica work surfaces 24 h after contamination.

Antigenicity and immunogenicity of equine influenza vaccines containing a Carbomer adjuvant

Abstract: Equine influenza vaccines containing inactivated whole virus and Carbomer adjuvant stimulated higher levels and longer lasting antibody to haemagglutinin in ponies than vaccines of equivalent antigenic content containing aluminium phosphate adjuvants. Five months after the third dose of vaccine containing Carbomer adjuvant, ponies were protected against clinical disease induced by an aerosol of virulent influenza virus (A/equine/Newmarket/79, H3N8). In contrast ponies which received vaccine containing aluminium phosphate adjuvant were susceptible to infection and disease. There was an inverse correlation between prechallenge levels of antibody detected by single radial haemolysis (SRH) and duration of virus excretion, pyrexia and coughing. All ponies with antibody levels equivalent to SRH zones of > or = 154 mm2 were protected against infection and all those with levels > or = 85 mm2 were protected from disease.

Information on which to base assessments of risk from environments contaminated with anthrax spores.

Abstract: Although there has been a considerable amount of research conducted into Bacillus anthracis, the causative agent of anthrax, the data are widely disseminated in the scientific literature and are therefore not always easy to assimilate. In view of continuing concern about potential anthrax contamination in environmental materials and sites, this review brings together the currently available information relating to the health hazards from B. anthracis. The relevance of the available information for risk assessment purposes is assessed.

Serodiagnosis of Crimean-Congo haemorrhagic fever.

Abstract: Several methods for demonstrating antibody to Crimean-Congo haemorrhagic fever virus were compared on serum samples taken from 101 patients during the acute stage of illness and at intervals for up to 59 months thereafter, with emphasis on early detection of the immune response. The deaths of 23 patients on days 5-14 of illness were ascribed to the effects of the disease; two patients died later from other causes. Very few of the patients who died from the acute illness mounted an antibody response detectable by the methods tested. Four patients who died and 18 who recovered were treated with immune plasma collected from recovered patients. Treated patients acquired IgG antibody from the plasma, but it was possible to discern the onset of an endogenous IgM response in those individuals who survived the disease by all of the methods tested. Indirect immunofluorescence (IF) tests detected IgM and/or IgG antibodies at the earliest on day 4 of illness in about 10% of patients who survived the disease, and by day 9 all survivors had antibodies demonstrable by IF. A biotin-streptavidin IF technique offered no advantage over the standard IF test for the early detection of IgG antibody, but demonstrated higher antibody titres and detected IgM antibody earlier in about a quarter of the patients tested. An IgM-capture enzyme-linked immunoassay (ELISA) and an IgG sandwich ELISA demonstrated higher antibody titres than did IF tests, and detected antibody responses at an earlier stage of infection than did IF tests in about one-fifth of patients, but the reverse was true in a similar proportion of instances. A competition ELISA, which detected total antibody activity, produced lower titres than did the IgM and IgG ELISAs, but yielded results which were in close agreement with the findings in IF tests. It was concluded that the IF tests were most convenient for use in making a rapid serodiagnosis of the disease.

The role of the pre-symptomatic food handler in a common source outbreak of food-borne SRSV gastroenteritis in a group of hospitals.

Abstract: A common source outbreak of small round structure virus (SRSV) gastroenteritis affected 81 patients and 114 staff in four hospitals served by one central hospital kitchen. Eating salad items was found to be significantly associated with illness. In a cohort study of a staff buffet function eating turkey salad sandwiches was associated with illness (relative risk = 2.4; 95% CI = 1.4-4.1; P = 0.003), and a case control study of patients in one hospital showed an odds ratio of 6.6 (95% CI = 1.0-71.6; P = 0.04) for eating tuna salad and becoming ill. One of two food handlers who prepared the salads became ill the day following food preparation; she also had a young child at home who had been ill with a gastrointestinal illness during the previous two days. Contamination of food by mechanical transmission of the virus from the child via clothes and hands of the mother, or pre-symptomatic faecal excretion in the mother are possible explanations of contamination of food.

An outbreak of Escherichia coli O157 associated with a children's paddling pool

Abstract: In May 1992, a small, circumscribed community outbreak of infection due to verotoxin-producing Escherichia coli O157 phage type 49 occurred in a semi-rural area of south-east Scotland. On the basis of stool cultures, six cases were identified, one of whom was asymptomatic. One child developed the haemolytic uraemic syndrome. Although the source of infection of the index case was not established nor could the extent of person-to-person spread be fully determined, the clinical, microbiological and epidemiological evidence available indicated that a children's paddling pool served as the focal point in the transmission of infection causing the outbreak.

Flies and water as reservoirs for bacterial enteropathogens in urban and rural areas in and around Lahore, Pakistan

Abstract: The study was conducted to isolate and characterize campylobacter, enterotoxigenic Escherichia coli-labile toxin (ETEC-LT), shigella and salmonella in flies and water. The material for the study, flies (n = 300) and water samples (n = 148), was collected from different localities in and around Lahore, Pakistan. Cultivation of the samples was performed on conventional standard media. Membrane filtration technique was used for water prior to culture. Determination of ETEC-LT was done by GM1 ELISA. Results of our study showed that flies and water were reservoirs for all the four pathogens, campylobacter, ETEC-LT, shigella and salmonella. Flies from the village were carrying fewer enteropathogens, while water from the village was found to be more contaminated as compared to the city. Campylobacter and ETEC-LT were the most frequently isolated pathogens in both flies and water. Thus the incidence of diarrhoeal disease in children of developing countries may be decreased by providing plenty of safe drinking water, improving excreta disposal, toilet facilities and giving education in personal hygiene.

Risk factors for hepatitis C virus infection. A case-control study of blood donors in the Trent Region (UK).

Abstract: The introduction of screening for hepatitis C virus (HCV) by the National Blood Transfusion Service identified donors who had acquired HCV infection. We undertook a case-control study amongst blood donors in the Trent Region to determine risks for HCV infection. A total of 74 blood donors confirmed positive for hepatitis C infection and 150 age, sex and donor venue matched controls were included in the study. Fifty-three percent of hepatitis C infected blood donors reported previous use of injected drugs compared to no controls; relative risk (RR) not estimatable (lower limit 95% CI = 20). Other risk factors were a history of: receipt of a blood transfusion or blood products RR = 3.6 (95% CI 1.5-8.3), having been a 'health care worker' RR = 2.8 (95% CI 1.1-7.6), tattooing RR = 3.3 (95% CI 1.2-8.7), and an association with having been born abroad RR = 3.2 (95% CI 1.1-9.5). No risk was shown for a history of multiple sexual partners, ear piercing or acupuncture. Injecting drug use explains more than 50% of hepatitis C infections in blood donors, a group who are less likely to have injected drugs than the general population.

The prevalence of hepatitis B and C in an antenatal population of various ethnic origins.

Abstract: A total of 3522 samples of serum, collected anonymously from women attending an antenatal clinic, was tested for hepatitis B surface antigen and antibody to hepatitis C. The prevalence of anti-HCV was low; only five confirmed positives were found (0.14%). The prevalence of hepatitis B overall was 0.56%, but was 1.04% in women from immigrant groups. Hepatitis B carriage is therefore four times more common than hepatitis C carriage in the antenatal population comprised of various ethnic origins. The patterns of infection in the two viruses are reversed, hepatitis B being more common in Asian, S.E. Asian and West Indian mothers and hepatitis C being more common in mothers of white Caucasian origin. Routine antenatal screening for anti-HCV is discussed.

Pseudomonas pseudomallei isolates collected over 25 years from a non-tropical endemic focus show clonality on the basis of ribotyping.

Abstract: Between 1966 and 1991, melioidosis, a disease caused by Pseudomonas pseudomallei that is mostly confined to tropical regions, occurred in farm animals and a farmer in temperate south-west Western Australia. Using an Escherichia coli probe containing a ribosomal RNA operon, P. pseudomallei DNA from isolates from 8 animals, a soil sample and the human case showed an identical ribotype on Southern blotting. The ribotype was different from the 3 commonest ribotypes seen in tropical Australia. This molecular typing supports the theory of clonal introduction of P. pseudomallei into a non-endemic region, with environmental contamination, local dissemination and persistence over 25 years. As melioidosis is often fatal in humans, such persistence in a temperate region is cause for concern.

Community-based study of the incidence of gastrointestinal diseases in The Netherlands

Abstract: The incidence of gastrointestinal diseases was studied in a community-based study in four regions of The Netherlands. Two grades of severity were distinguished--1: diarrhoea or vomiting and at least 2 additional symptoms within the period of 1 week, and 2: diarrhoea or vomiting and at least 2 additional symptoms occurring on the same day lasting at least 2 days within the period of 1 week. The incidence of gastrointestinal episodes was calculated to be 630 for grade 1 and 180 for grade 2 disease per 1000 person-years, after correction for age and sex. The incidence was higher for women than for men (relative risk 1.25) and lower for those in the 19-64-year-old age group when compared to those younger or older (relative risk 0.75 and 0.40, respectively). Independent of the degree of severity of the symptoms, about 20% of the patients had consulted a general practitioner, about half in person and half by telephone. It is concluded that community studies are essential to assess the real incidence of gastrointestinal diseases in the population.

Prevalence of serum IgG antibodies to Puumala virus (haemorrhagic fever with renal syndrome) in northern Sweden.

Abstract: A stratified and randomly-selected population sample was identified in 1990 in order to study the seroprevalence of nephropathia epidemica (haemorrhagic fever with renal syndrome) in Northern Sweden. Sera from 1538 subjects (750 men, 788 women), 25-64 years of age, were analysed for the presence of Puumala virus (PUV) specific-IgG by the indirect immunofluorescence antibody test. Specific IgG was detected in sera from 83 subjects (5.4%). Men and women had similar seroprevalence rates. The highest seroprevalences were found in subjects 55 years or older (8.0%) and among farmers and forestry workers (15.9%). The geographic distribution of seropositive individuals was uneven and there were significantly more seropositive persons in rural than in urban areas (P < 0.05).

Age-specific antibody prevalence to hepatitis A in England: implications for disease control

Abstract: Sera from an age-stratified sample of 7196 individuals, submitted for diagnostic purposes to four public health laboratories in England in 1986/7, were tested for hepatitis A antibody. The serological profiles, which showed marked regional differences, were consistent with declining incidence in the past. The decline in the incidence of hepatitis A has resulted in an increase in susceptibility in adults. This has three main consequences: an increase in the average age of infection may be leading to an increase in morbidity; normal immunoglobulin may become less protective against hepatitis A; the risk of transmission through blood products contaminated by viraemic blood donors may rise. Current average annual incidence in 5-14-year olds was estimated to vary between regions from 0.5-1.9%. This supports the view that, in the absence of a vaccination programme, hepatitis A will remain endemic unless there are further improvements in living conditions and standards of hygiene. A vaccine giving long-lasting protection could eliminate hepatitis A transmission with modest coverage at a young age. Targeting childhood vaccination on economically deprived areas or using vaccine to control outbreaks might be more effective policies.

The diagnosis of toxoplasmosis using IgG avidity.

Abstract: Current methods to establish the duration of toxoplasma infection in pregnant women and for the diagnosis of toxoplasmosis in the neonate or HIV infected patient have significant limitations. We assessed the precision of a commercial ELISA for the detection of toxoplasma specific IgG and adapted the assay to measure avidity using an elution agent washing step. The sensitivity and specificity of the ELISA were 100 and 75% respectively and optimal measurement of avidity was achieved using 6 M urea as the elution agent. Toxoplasma lymphadenopathy of less than 3 months duration was associated with low avidity specific IgG but some discordant findings were recorded. Serial measurement of IgG avidity assisted the distinction between actively produced antibody in infants with congenital toxoplasmosis and passively acquired antibody of maternal origin in uninfected babies. There was no significant difference between avidity levels in HIV infected patients with or without cerebral toxoplasmosis.

Nosocomial Legionnaires' disease in England and Wales, 1980-92.

Abstract: Two hundred and eighteen nosocomial cases of Legionnaires' disease with 68 deaths were reported to the National Surveillance Scheme for Legionnaires Disease between 1980 and 1992, representing 15% of the reported infections acquired in England and Wales. Twenty-two nosocomial outbreaks accounted for 135 (62%) of these cases, the remainder occurring as single cases either in hospitals where other single cases or outbreaks had been reported in different years or as 'sporadic' cases in hospitals from which no other cases were reported. A clinical history prior to onset of Legionnaires' disease was available for 124 patients, 61 of whom had undergone recent transplant therapy or were immunosuppressed for other reasons. Sixty cases (27%) were diagnosed by culture of the organism and isolates from 56 patients were typed; 25 (42%) were non L. pneumophila serogroup 1 infections. Methods for prevention and control of nosocomial outbreaks are discussed, in particular the susceptibility to Legionnaires' disease of certain groups of hospital patients.

Rubella seroepidemiology in a non-immunized population of São Paulo State, Brazil.

Abstract: A rubella serological survey of 476 individuals selected by cluster sampling technique from Caieiras, a small town located in the outskirts of Sao Paulo city, southeastern Brazil, was carried out over the period November 1990-January 1991. The aim of the study was to characterize rubella epidemiology in a representative non-immunized community in south east Brazil. The survey comprised a seroprevalence study, stratified by age (0-40 years) and a seroconversion study of rubella vaccine in non-infected children below 2 years of age. Mathematical techniques were applied to resultant data sets to determine the age dependent rates of decay in the proportion of individuals with maternally derived antibodies, vaccine seroconversion, and infection of susceptibles, termed the force of infection, and to estimate the average age at first infection.

Survey on the distribution of the gene 4 alleles of human rotaviruses by polymerase chain reaction

Abstract: The presence of six gene 4 alleles (or VP4 genotypes) in human rotaviruses has been recognized. Using 16 representative cultivable human rotavirus strains, we confirmed the specificity of VP4 genotyping by polymerase chain reaction (PCR) using the nested oligonucleotides specific to each of the four representative gene 4 alleles. Using the PCR, we surveyed the gene 4 alleles of 199 human rotaviruses in stools collected in Japan and Thailand. Strains with the gene 4 allele, corresponding to P1A serotype, were shown to be the most prevalent, but two strains with P2 gene 4 allele and one strain with P3 gene 4 allele were detected in Thailand and in Japan, respectively.

Identification of astrovirus serotypes from children treated at the Hospitals for Sick Children, London 1981–93

Abstract: An enzyme immunoassay (EIA) for astrovirus type 1 together with immune electronmicroscopy (IEM) was used to type a collection of 162 astroviruses obtained from 1981-93 from children with diarrhoea. The EIA was found to be specific for astrovirus type 1. Astrovirus types 2-4 were typed by IEM. Astrovirus type 1 was the prevalent serotype 107/125 (86%), followed by type 3 (8%), type 4 (6%) and type 2 (1%). Six samples containing astrovirus could not be typed or detected by EIA because they were coated with coproantibodies; 11 others were not identified. Virus particles could no longer be detected in 15/162 (9%) samples following storage for > or = 2 years. Selected samples containing astrovirus types 1-4 were passaged in CaCO2 cells and their identity confirmed by one or both assays. One sample was shown to have remained viable for 10 years when stored as an aqueous suspension at -20 degrees C. Two patients with severe combined immune deficiency disease (SCID) were shown to be excreting astrovirus type 1 for 32 and 102 days respectively. One child was simultaneously shedding rotavirus and the other child was excreting adenovirus.