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Biomedical subjects

J G Wheeler

Publications and source records attributed to J G Wheeler.

At least 19 recordsLinked to original sources
PubMed2006

Serotypes, intimin subtypes, and antimicrobial resistance patterns of atypical enteropathogenic Escherichia coli isolated in England from 1993 to 1996.

The aim of this study was to characterise the atypical enteropathogenic Escherichia coli (EPEC) strains isolated during a study of intestinal infectious disease in the UK by serotyping, intimin subtyping, and antimicrobial resistance typing. Serotypes, intimin subtypes, and resistance patterns of strains from cases were then compared with those from the control group. A wide range of serotypes, intimin subtypes, and antimicrobial resistance patterns was identified in isolates from both cases and controls, with O70:H11 and O111:H- being the most frequently detected serotypes. The most common intimin types were gamma and gamma(2). Thirty-six percent of the EPEC isolates were resistant to at least one antimicrobial agent. No significant differences in the characteristics of EPEC strains isolated from patients with symptoms of gastrointestinal disease versus those isolated from healthy controls were detected, although strains harbouring the beta-intimin subtype were more commonly isolated from children under 5 years of age (p=0.002). The compilation of data on atypical EPEC strains presented here indicates the need for further study of their virulence and epidemiology in order to assess their significance as human pathogens.

Adhesins, Bacterial↗
PubMed2004

Adolescent reproductive health and awareness of HIV among rural high school students, North Western Ethiopia.

Ethiopia is faced with an increasing problem from HIV infection, and the vulnerability of adolescents is a key concern. There is little information on the knowledge, attitudes and practices of this age group with respect to HIV, sexually transmitted diseases and preventive measures. We conducted a cross-sectional study among 260 students from two rural high schools in North Western Ethiopia. We found that although the general awareness of HIV was high, correct knowledge of the virus and its modes of transmission was shown in only 44% of adolescent boys and 41% of adolescent girls. Knowledge of HIV and condoms was lower among students whose parents were farmers, significant so among girls (p=0.02). Use of condoms among sexually active single male students (49%) was insufficient but was higher than among adolescents in many other African settings. Knowledge of STDs was generally low: 82% of adolescent males and 37% of adolescent females had some awareness of STDs. Almost 20% of sexually active males in the study had previously experienced an STD, almost all of whom had visited a commercial sex worker. Targeted interventions are warranted among adolescents and sex workers in Ethiopia complemented by STD treatment services.

Adolescent↗
PubMed2004

Antibiotic use and the development of Crohn's disease.

BACKGROUND: Few environmental determinants of Crohn's disease are well established. Some observational data exist to implicate antibiotic use as a risk factor but these are derived from studies using questionnaires to assess reported antibiotic use that were susceptible to recall bias. We have therefore explored this relationship in prospectively gathered data. METHODS: We selected incident cases of Crohn's disease from the General Practice Research Database with at least five years of data prior to diagnosis. Controls with five years of complete data were randomly selected. Data were extracted on smoking, drug prescriptions, age, sex, and a variety of symptoms and diagnoses that might be indicative of occult Crohn's disease. Logistic regression was used to investigate the relationship between antibiotic use and Crohn's disease. RESULTS: A total of 587 Crohn's disease cases and 1460 controls were available for analysis. We found that antibiotic use 2-5 years pre-diagnosis occurred in 71% of cases compared with 58% of controls (p<0.001), and the median number of courses was two in the cases and one in the controls (p<0.001). Adjusting for age, sex, smoking, and use of other drugs, antibiotic use had an odds ratio of 1.32 (1.05-1.65). We were unable to show specificity to any subgroup of antibacterials. Associations similar to that with antibiotics were also found with oral contraceptive, cardiovascular, and neurological drugs. CONCLUSIONS: We found a statistically significant association between Crohn's disease and prior antibiotic use. This cannot be explained by recall bias, but due to lack of specificity it is unclear whether it is causal.

Adolescent↗
PubMed2003

The infectious intestinal disease study of England: a prospective evaluation of symptoms and health care use after an acute episode.

The sequelae of Infectious Intestinal Disease (IID) in a population-based sample of cases and matched controls were investigated for a period of 3 months following the initial infection. Incident cases of IID presenting to GPs or occurring in the community and controls were studied at 3 weeks and over a 3-month follow-up period. Cases were six times more likely than controls to have gastrointestinal symptoms, particularly diarrhoea, at 3 weeks. Ten per cent of cases consulted their GP in the 3 months after episode and 2.3% were referred to hospital. GP presentation rates were twice as high in cases. Gastrointestinal symptoms persist after IID, leading to an increased likelihood of GP consultation and hospital referral. Diagnosis of irritable bowel syndrome may be more likely following IID. The burden of IID is likely to be considerable given its high incidence and the frequency of such sequelae.

Adolescent↗
PubMed2003

The detection of antibodies against Schistosoma mansoni soluble egg antigens (SEA) and CEF6 in ELISA, before and after chemotherapy.

Circulating IgG antibody reactivity and excreted egg counts were investigated in 489 Kenyans given chemotherapy for schistosomiasis mansoni. Antibody reactivity was measured in ELISA, using either unfractionated aqueous soluble constituents of Schistosoma mansoni eggs (SEA) or CEF6 (a soluble fraction of S. mansoni eggs containing two cationic antigens) as the antigen source. Antibody reactivity for each antigen source was strongly associated with egg counts, both pre- and post-treatment. Approximately 6 months after chemotherapy, egg counts were zero in 84% of the subjects. The mean optical densities (OD) measured in the post-treatment ELISA were 60% (CEF6) or 45% (SEA) lower than the pre-treatment values, the reduction in the OD with CEF6 as antigen source being significantly greater than that observed with SEA (P <0.001). The usefulness of an assay for antibody reactivity in monitoring the effects of the treatment of schistosomiasis is discussed.

Adolescent↗
PubMed2002

Vero cytotoxin-producing Escherichia coli in a study of infectious intestinal disease in England.

An investigation of infectious intestinal disease in England included examination of feces for Vero cytotoxin-producing Escherichia coli (VTEC). Using DNA probe hybridization 27 VTEC strains were identified, 12 were from cases, and of these three belonged to serogroup O157. The remaining 15 strains were isolated from controls. The strains were confirmed biochemically as E. coli, they were serotyped and characterized according to their toxin production, the presence of sequences encoding intimin (eae) and enterohemolysin was determined and resistance to antimicrobial agents was determined. Six of the nine cases with non-O157 VTEC were less than 16 years old, only two of the 15 controls were under 16. Infection with more than one micro-organism was also considered.

Adolescent↗
PubMed2001

Frequent and persistent, asymptomatic Plasmodium falciparum infections in African infants, characterized by multilocus genotyping.

To determine the duration and complexity of naturally acquired Plasmodium falciparum infections in small children, a longitudinal cohort study of 143 newborns was conducted in coastal Ghana. On average, children experienced 2 episodes of infection in their first 2 years of life, the median duration of an asymptomatic infection was <4 weeks, and estimates of the mean number of parasite genotypes per infection were 1.15-2.28. Nevertheless, 40% of the children experienced infections lasting </=12 weeks, and both the duration and complexity of infections increased with age. The longest period of continual infection was 64 weeks, and the maximum persistence of a single parasite genotype was 40 weeks. Thus, malaria infections in infants <5 months old tend to be asymptomatic and rapidly cleared; persistent asymptomatic parasitemia is more common in children >5 months old. The ability of very young children to clear or control malaria infections indicates the presence of effective innate or immune antiparasite mechanisms.

Age Factors↗
PubMed2001

Immune modulation after measles vaccination of 6-9 months old Bangladeshi infants.

Measles still causes high mortality in children younger than 1 year of age. Administration of high titre measles vaccines before 7 months of age led to increased overall mortality, raising questions as to the immunological effects of measles vaccine in young infants. We investigated the immune response to standard titre vaccines given to children in Bangladesh in a single dose at age 9 months, or two doses at 6 and 9 months. Of the children vaccinated at age 9 months, 95% serocoverted, compared with 70% at age 6 months. Delayed-type-hypersensitivity reactions to candida antigen were significantly reduced in both vaccine groups at 6 weeks post-vaccination, but responses to other recall antigens studied were not significantly different from controls. In both vaccine groups, peripheral blood lymphocytes isolated at 6 and 24 weeks after vaccination showed significantly higher expression of activation markers upon in vitro stimulation, and a sustained increase in IL-2 production. These findings suggest prolonged immune activation after measles vaccination at the same time as some reduction in delayed hypersensitivity responses. Further study of the clinical effects of these changes is warranted.

Antibodies, Viral↗
PubMed2001

Advocating for children's health at the state level: lessons learned.

This article documents the successful creation and promotion of a bill to fund a nurse home visitation program for high-risk mothers in Arkansas. It illustrates several key factors in successful advocacy by pediatricians working in an academic setting: a realistic time commitment; a community needs assessment, data assimilation, and review of existing resources; the identification and incorporation of stakeholders; a narrow focus on the area of greatest need; the backing of political partners; and favorable opportunities to advance child health issues.

Arkansas↗
PubMed2001

A study of infectious intestinal disease in England: risk factors associated with group A rotavirus in children.

OBJECTIVE: To identify risk factors for infectious intestinal disease (IID) due to rotavirus group A in children aged under 16 years. METHODS: Case-control study of cases of IID with rotavirus infection presenting to general practitioners (GPs) or occurring in community cohorts, and matched controls. RESULTS: There were 139 matched pairs. In children under 16 years the following risk factors were significantly associated with rotavirus IID: living in rented council housing (adjusted OR = 3.78, P = 0.022), accommodation with more than five rooms (OR = 0.72, P = 0.002), contact with someone ill with IID (OR = 3.45, P < 0.001). Some foods were associated with decreased risk. In infants, bottle feeding with or without breast feeding was associated with increased risk (OR = 9.06, P < 0.05). CONCLUSIONS: Contact with persons with IID, living in rented council housing and accommodation with fewer rooms, were significant risk factors for sporadic rotavirus IID in children whereas breast feeding is protective in infants.

Adolescent↗
PubMed2001

The study of infectious intestinal disease in England: risk factors for cases of infectious intestinal disease with Campylobacter jejuni infection.

This is a case-control study aimed at identifying risk factors for intestinal infection with Campylobacter jejuni. Cases were defined as subjects with diarrhoea occurring in community cohorts or presenting to General Practitioners (GPs) with Campylobacter jejuni in stools. Controls were selected from GP lists or cohorts, matched by age, sex, and GP practice. Travel abroad and consumption of chicken in a restaurant were statistically significantly associated with being a case. There was no statistically significant risk associated with consumption of chicken other than in restaurants nor with reported domestic kitchen hygiene practices. Consumption of some foods was associated with a lower risk of being a case. Most cases remained unexplained. We suggest that infection with low numbers of micro-organisms, and individual susceptibility may play a greater role in the causation of campylobacter infection than previously thought. It is possible that in mild, sporadic cases infection may result from cross contamination from kitchen hygiene practices usually regarded as acceptable. Chicken may be a less important vehicle of infection for sporadic cases than for outbreaks, although its role as a source of infection in both settings requires further clarification in particular in relation to the effect of domestic hygiene practices. The potential effect of diet in reducing the risk of campylobacteriosis requires exploration.

Campylobacter Infections↗
PubMed2001

Persistence of anti-leptospiral IgM, IgG and agglutinating antibodies in patients presenting with acute febrile illness in Barbados 1979-1989.

The persistence of anti-leptospiral IgM and IgG antibodies and agglutinating antibodies was studied in serologically confirmed cases of severe leptospirosis during the acute illness and over periods of several years after recovery. The antibody response in non-leptospirosis patients presenting to hospital with similar symptoms over the same period of time was used to estimate the background antibody level to leptospirosis in the community. All patients enrolled in the study had blood samples collected twice in the acute stage of illness, once during convalescence and then annually from the time of initial hospitalisation until the end of the study period. Six hundred and thirty-eight patients presented to hospital with acute febrile illness, of whom 321 were diagnosed with leptospirosis. Patients who had severe leptospirosis commonly remained seropositive, with IgM, IgG and agglutinating antibodies detectable for several years after infection. A significant proportion of cases had high titres of agglutinating antibody detectable by the microscopic agglutination test (> or = 800). There were marked differences in the magnitude and duration of persistence of agglutinating antibodies directed against different serogroups. More than 20% of cases with evidence of infection with serogroup Autumnalis retained titres of >800, 4 years after the acute illness. In one case a titre of 800 was detected 11 years after infection. Persistence of agglutinating antibody titres can create problems in interpretation of serological results and make it impossible to estimate the time of infection, given a specific titre. This study demonstrates that in endemic areas where seroprevalence is high, use of a single elevated titre is not reliable to define a current infection.

Agglutination Tests↗
PubMed2001

Characterisation of strains of enteroaggregative Escherichia coli isolated during the infectious intestinal disease study in England.

Strains of Escherichia coli, hybridising with a DNA probe for enteroaggregative E. coli (EAggEC), were isolated from patients with infectious intestinal disease (IID) or gastro-enteritis, and healthy controls during the study of IID in England. Of 3506 cases presenting with an IID, 160 (4.6%) had faecal EAggEC as compared with 46 (1.7%) of 2772 healthy controls, 53% of EAggEC isolated from each of the 'case' and the 'control' groups adhered in a 'stacked-brick' formation. Strains from cases and controls belonged to over 39 and 14 different serogroups respectively, and approximately half of the strains isolated did not react with antisera in the current somatic antigen serotyping scheme. Forty-nine cases with EAggEC (31%) had a known history of foreign travel. Over 50% of strains isolated from cases and controls were resistant to one or more of eight antimicrobials, and antimicrobial resistance was not statistically significantly more common among cases with a known history of foreign travel (p = 0.57). These data form part of the largest investigation carried out on these organisms in the UK to date and provide the most comprehensive analysis of strains of EAggEC isolated from the general population of England.

Case-Control Studies↗
PubMed2001

Tuberculosis contacts but not patients have higher gamma interferon responses to ESAT-6 than do community controls in The Gambia.

The Mycobacterium tuberculosis antigen ESAT-6 has been proposed for tuberculosis immunodiagnosis. In The Gambia, 30% of community controls produced gamma interferon (IFN-gamma) in response to ESAT-6. Increased proportions of responders and intensities of responses were found in household contacts. Responses that were initially low in tuberculosis patients increased after treatment. An ESAT-6 IFN-gamma assay will be of limited use in the diagnosis of tuberculosis in countries where tuberculosis is endemic. Its role in contact tracing should be evaluated further.

Adolescent↗
PubMed2001

Impact of a waiting room videotape message on parent attitudes toward pediatric antibiotic use.

OBJECTIVE: To reduce the injudicious use of antibiotics, we developed an educational strategy that focused on parents of pediatric patients and their physicians. METHODS: This intervention was conducted in 5 pediatric practices in Arkansas during a 9-month period. Baseline data on parent attitudes about antibiotics and physician practice habits were measured by questionnaire. During the following 36 weeks, an educational videotape about the judicious use of antibiotics was played in waiting rooms. The videotape on antibiotics used a standard script based on the recommendations of the American Academy of Pediatrics. The physicians and staff at each site were actors in the videotape. During week 2 and week 36 of videotape use, parent attitudes were measured again. After the baseline week, the physicians and staff in each site were provided a standard in-service review of the American Academy of Pediatrics recommendations for judicious use of antibiotics. A study nurse recruited patients, administered questionnaires, and reviewed charts on-site. RESULTS: Parents who were exposed to the videotape were significantly less inclined to seek antibiotics for viral infections. Passively provided pamphlets were not read. No significant change in antibiotic prescribing by physicians was seen. CONCLUSION: Parent-focused passive education tools are effective at changing parent attitudes toward the use of antibiotics. Although physicians have blamed parent attitudes and demands for the overuse of antibiotics, changes in parent attitudes in this study were not associated with changes in prescribing rates. Changes in parent attitudes may be necessary but do not seem sufficient for changes in antimicrobial prescribing patterns.

Adolescent↗