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R W Peeling

Publications and source records attributed to R W Peeling.

At least 19 recordsLinked to original sources
PubMed2004

A prospective study of Chlamydia pneumoniae infection and risk of MS in two US cohorts.

BACKGROUND: Chlamydia pneumoniae (Cpn) has been proposed as a possible etiologic agent in multiple sclerosis (MS). However, previous studies were cross-sectional and could not assess whether Cpn infection preceded the onset of MS. METHODS: The authors conducted a prospective nested case-control study among 3 million US Army personnel and 121,466 members of the Kaiser Permanente Medical Care Program (KPMCP) cohort. Serum samples collected prior to onset of MS symptoms were available for 83 MS cases in the Army and 46 in the KPMCP cohort. Two controls were matched to each case on age, sex, and date of blood collection. Microimmunofluorescence was used to measure serum immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody titers to Cpn; IgG titers > or 1:16 were considered positive for past Cpn infection. RESULTS: Seropositivity for Cpn was not significantly associated with risk of MS in either cohort (Army: OR = 1.0; 95% CI 0.6, 1.8; KPMCP: OR = 1.5; 95% CI 0.7, 3.1) or in the pooled analysis (OR = 1.2; 95% CI 0.8, 1.9). Serum levels of anti-Cpn IgG antibody were also not associated with an increased risk of MS in the Army (OR for a fourfold difference in antibody titers = 0.9; 95% CI 0.7, 1.2) or in the pooled analysis (OR = 1.2; 95% CI 0.9, 1.4), but a significant increase in risk was seen in the KPMCP cohort (OR = 1.7; 95% CI 1.2, 2.5). The difference between these results in the Army and the KPMCP cohort was significant (p = 0.01). CONCLUSIONS: Neither Cpn seropositivity nor serum anti-Cpn IgG antibody titers predicted risk of developing MS. However, due to the heterogeneity of results between cohorts, we cannot exclude the possibility that infection with Cpn may modify the risk of MS.

Adolescent↗
PubMed2004

Syphilis.

Explore the source record for details and available documents.

Anti-Bacterial Agents↗
PubMed2003

Sensitivity requirements for the point of care diagnosis of Chlamydia trachomatis and Neisseria gonorrhoeae in women.

BACKGROUND/OBJECTIVES: Most current tests for Neisseria gonorrhoeae and Chlmydia trachomatis require the support of a laboratory, and results are not usually available before the patient has left the clinic. This delay can lead to patients not returning for treatment and may allow further STI transmission to occur. Current rapid point of care (POC) STI tests and the syndromic approach are less sensitive than gold standard tests, but allow treatment at the initial visit. This study estimates the required sensitivity of POC tests that ensures as many STIs are averted as with current gold standard tests. METHODS: A mathematical model is developed to compare the STIs averted using different STI diagnostic methods. Data from Benin, South Africa, Tanzania, and England are used to explore how the required sensitivity differs between settings. RESULTS: The required sensitivity of a POC test is low if there is significant STI transmission during the delay in treatment for the gold standard test and/or few women return for treatment. For example, the required sensitivity of a POC test for C trachomatis is 50% (gold standard test sensitivity is 90%) if either 55% return for treatment and there is no STI transmission, or 80% return for treatment and 50% of infected women infect their partner during the delay in treatment. Furthermore, in these settings a POC test of moderate sensitivity can lead to significantly more STI averted than the gold standard test. CONCLUSIONS: These results support the use of moderate sensitivity POC tests in scenarios where many women will not return for treatment, and in populations where the delay in treatment would result in significant STI transmission.

Benin↗
PubMed2003

Chlamydia species as a cause of community-acquired pneumonia in Canada.

Chlamydia pneumoniae has been implicated as a cause of community-acquired pneumonia (CAP) in several studies. However, there has been no comprehensive study of the role of Chlamydia species (C. pneumoniae, C. psittaci (avian and feline strains) and C. pecorum) as a cause of CAP. The aim of the present study was to determine the role of C. pneumoniae, C. psittaci and C. pecorum as causes of CAP. A prospective cohort observational study of CAP was conducted at 15 teaching centres in eight Canadian provinces between January 1996-October 1997. Acute (n=539) and convalescent (n=272) serum samples were obtained for determination of antibody titres to C. pneumoniae, C. psittaci, C. pecorum, C. trachomatis, Mycoplasma pneumoniae, Legionella pneumophila serogroups I-VI, Streptococcus pneumoniae and various respiratory viruses. Twelve of 539 (2.2%) patients had acute C. pneumoniae pneumonia and an additional 32 (5.9%) had possible acute infection. C. pneumoniae was the sole pathogen in 16 of 42 (38.1%) of these patients. The most common copathogens were S. pneumoniae, respiratory syncytial virus and influenza virus type A. C. pneumoniae pneumonia patients were older and more likely to show congestive heart failure compared to bacteraemic S. pneumoniae patients. The latter had a lower mean diastolic blood pressure, a higher white blood cell count and a lower arterial carbon dioxide tension. Two patients had antibody titres suggestive of recent infection with the feline strain of C. psittaci. Although numerically Chlamydia pneumoniae is an important cause of community-acquired pneumonia, no distinctive clinical features associated with this pathogen were detected in the present study. Feline Chlamydia psittaci may cause a few cases of community-acquired pneumonia. Avian Chlamydia psittaci should be considered only if there is a compatible epidemiological history.

Adolescent↗
PubMed2002

Lymphogranuloma venereum.

Lymphogranuloma venereum is caused by serovars of Chlamydia trachomatis. It is rare in industrialised countries, but is endemic in parts of Africa, Asia, South America, and the Caribbean. We discuss its clinical features, diagnosis, and management.

Anti-Bacterial Agents↗
PubMed2002

The value of mass screening for chlamydia control in high prevalence communities.

The social context and epidemiology of STIs in remote communities in Northern Canada was examined. These communities have a persistently high reported incidence of gonorrhoea and chlamydial infection. They remain in the hyperendemic phase of the N. gonorrhoeae and C. trachomatis epidemics. They are ethnically and culturally homogeneous and contain no readily identifiable core groups, making it impossible to distinguish between spread and maintenance networks. Mass screening of the adult population can reduce the reservoir of C. trachomatis infection under these circumstances. It is particularly important to target men in settings such as this where women are routinely screened in antenatal and family planning clinics.

Adolescent↗
PubMed2001

Standardizing Chlamydia pneumoniae assays: recommendations from the Centers for Disease Control and Prevention (USA) and the Laboratory Centre for Disease Control (Canada).

Chlamydia pneumoniae has been associated with atherosclerosis and several other chronic diseases, but reports from different laboratories are highly variable and "gold standards" are lacking, which has led to calls for more standardized approaches to diagnostic testing. Using leading researchers in the field, we reviewed the available approaches to serological testing, culture, DNA amplification, and tissue diagnostics to make specific recommendations. With regard to serological testing, only use of microimmunofluorescence is recommended, standardized definitions for "acute infection" and "past exposure" are proposed, and the use of single immunoglobulin (Ig) G titers for determining acute infection and IgA for determining chronic infection are discouraged. Confirmation of a positive culture result requires propagation of the isolate or confirmation by use of polymerase chain reaction (PCR). Four of 18 PCR assays described in published reports met the proposed validation criteria. More consistent use of control antibodies and tissues and improvement in skill at identifying staining artifacts are necessary to avoid false-positive results of immunohistochemical staining. These standards should be applied in future investigations and periodically modified as indicated.

Bacteriological Techniques↗
PubMed2000

Surveillance for outbreaks of respiratory tract infections in nursing homes.

BACKGROUND: Outbreaks of respiratory tract infections are common in long-term care facilities for older people. The objective of our study was to determine both the frequency of such outbreaks and their clinical and epidemiological features. METHODS: Prospective surveillance for outbreaks of respiratory tract infections and a retrospective audit of surveillance records were conducted in 5 nursing homes in metropolitan Toronto over 3 years. The clinical manifestations of infected residents were identified and microbiological investigations for causal agents were conducted. RESULTS: Sixteen outbreaks, involving 480 of 1313 residents, were identified prospectively during 1 144 208 resident-days of surveillance, for an overall rate of 0.42 infections per 1000 resident-days. Another 30 outbreaks, involving 388 residents, were identified retrospectively. Outbreaks occurred year-round, with no seasonal pattern. Pathogens included influenza virus, parainfluenza virus, respiratory syncytial virus, Legionella sainthelensi and Chlamydia pneumoniae. Multiple pathogens were detected in 38% (6/16) of the prospectively identified outbreaks. Of the 480 residents in the prospectively identified outbreaks 398 (83%) had a cough, 194 (40%) had fever and 215 (45%) had coryza. Clinical findings were nonspecific and could not be used to distinguish between causal agents. Pneumonia developed in 72 (15%) of the 480 residents, and 58 (12%) required transfer to hospital. The case-fatality rate was 8% (37/480). INTERPRETATION: Our findings emphasize the importance of adequate surveillance for outbreaks of respiratory tract infections in nursing homes and of early diagnosis so that appropriate interventions can be promptly instituted.

Aged↗
PubMed2000

Serologic markers for Chlamydia pneumoniae in asthma.

BACKGROUND: Chlamydia pneumoniae infection has been reported as a possible etiologic agent in asthma, which in primary care settings often appears to be initiated by acute respiratory infections. OBJECTIVE: To determine if serologic markers for C. pneumoniae are associated with adult asthma that first became symptomatic after an acute respiratory illness (asthma associated with infection: AAWI). METHODS: Serum samples from 164 primary care outpatients, mean age 44 years, (68 with AAWI; 36 with atopic, occupational or exercise-induced asthma (non-AAWI); 16 nonasthmatic patients with acute bronchitis; and 44 asymptomatic nonasthmatic controls) were tested for the presence of C. pneumoniae-specific IgG and IgA antibodies. Levels of chlamydial heat shock protein 60 (CHSP60) antibody were also measured. Those positive for CHSP60 were tested for C. pneumoniae-specific IgE antibodies by immunoblotting. RESULTS: Statistically significant differences in IgG and IgA seroreactivity were noted between groups: acute bronchitis and AAWI had the highest levels (93% to 94% IgG seroreactivity, 69% to 75% IgA seroreactivity) whereas non-AAWI and asymptomatic controls had the lowest levels (61% to 84% IgG seroreactivity, 31% to 43% IgA seroreactivity, P < .02 after adjustment for age, sex and smoking). CHSP60 antibodies were significantly more prevalent in AAWI than in non-AAWI (19% versus 3%, P = .02). IgE antibodies against C. pneumoniae 60, 62, and/or 70 kD antigens were detected in 5 of 13 CHSP60 positive AAWI patients. Persistent IgG, IgA, and CHSP60 seroreactivities were noted in all seropositive asthma patients with serial serum samples. CONCLUSIONS: Serologic markers of C. pneumoniae infection were associated with acute bronchitis and with asthma that first became symptomatic following respiratory illness. Serologic responses to C. pneumoniae may be useful in the classification and diagnosis of asthma.

Adult↗
PubMed2000

Chlamydia pneumoniae serology: interlaboratory variation in microimmunofluorescence assay results.

The lack of standardization in chlamydia serology has made interpretation of published data difficult. This study was initiated to determine the extent of interlaboratory variation of microimmunofluorescence (MIF) test results for the serodiagnosis of Chlamydia pneumoniae infections. Identical panels of 22 sera were sent to 14 laboratories in eight countries for the determination of IgG and IgM antibodies by MIF. Although there was extensive variation in the numeric titer values, the overall percentage agreement with the reference standard titers from the University of Washington was 80%. For results by serodiagnostic category, the best agreement was for four-fold rise in IgG titers, while the lowest agreement was for negative or low IgG titers. Agreement for IgM titers was 50%-95%. Four laboratories failed to discern false-positive IgM titers possibly because of the presence of rheumatoid factor. Further studies are underway to determine the source of interlaboratory variation for the MIF test.

Antibodies, Bacterial↗
PubMed1999

Reproductive-tract infections in women in low-income, low-prevalence situations: assessment of syndromic management in Matlab, Bangladesh.

BACKGROUND: In the control of reproductive-tract infections, including sexually transmitted infections (STIs), in low-income and middle-income countries, WHO recommends syndromic management for individuals with symptoms. This intervention was initially developed in areas where prevalence of such infections is high. We investigated the clinical effectiveness and cost of this approach among a group of women with a low prevalence of infection. METHODS: During a 5-month period, we investigated all women complaining of abnormal vaginal discharge and seeking care at maternal and child health/family-planning centres in Matlab, Bangladesh, for the presence of laboratory-diagnosed reproductive-tract infections and STIs. Syndromic diagnoses made by trained health-care workers were compared with laboratory diagnosis of infection. We then calculated the costs of treating women by means of the recommended WHO algorithm and an adapted algorithm incorporating use of a speculum and simple diagnostic tests. FINDINGS: The prevalence of endogenous infections among 320 women seen was 30%. Cervical infections (Neisseria gonorrhoeae and Chlamydia trachomatis) were found in only three women. The WHO algorithm had a high sensitivity (100%) but a low specificity (zero for bacterial vaginosis, candida, and Trichomonas vaginalis). The speculum-based algorithm had a low sensitivity (between zero and 59%) but a higher specificity (79-97%). Between 36% and 87% of costs would have been spent on uninfected women. INTERPRETATION: The high rate of overtreatment in the population studied carries both financial and social costs--the latter in potentially exposing women misdiagnosed as having an STI to threats of domestic disruption or even violence. We make recommendations for management programmes in areas of low STI prevalence and low income.

Adolescent↗
PubMed1999

Analysis of the original antigenic sin antibody response to the major outer membrane protein of Chlamydia trachomatis.

The anamnestic antibody response to the Chlamydia trachomatis major outer membrane protein (MOMP) was evaluated in mice after priming with serovar C and boosting either with the homologous serovar or with heterologous serovars (A, H, K, and B). Microimmunofluorescence antibody responses demonstrated that boosting with heterologous serovars strongly recalled antibody to serovar C, typical of an original antigenic sin (OAS) response. Boosting with serovars antigenically related to serovar C (A, H, and K) recalled antibody to the variable domain 1 (VD1) peptide of the MOMP of serovar C as determined by a pin-peptide ELISA. Complete amino acid substitution analysis of the VD1 peptide epitope of the MOMP showed that the original antigenic sin response to each boosting serovar contained antibodies with unique patterns of VD1 peptide recognition. The data suggest that antigenically related C. trachomatis serovars differentially recruit B cell lineages from a heterogeneous memory B cell pool that had been induced by priming with the original serovar and thus account for the OAS antibody response.

Amino Acid Sequence↗
PubMed1999

Association of Chlamydia trachomatis heat-shock protein 60 antibody and HLA class II DQ alleles.

A total of 113 female commercial sex workers had individual alleles for HLA class II genes determined by using labeled sequence-specific oligonucleotide probes to hybridize to polymerase chain reaction products of amplified DNA. Women also had microimmunofluorescent (MIF) antibody titers to Chlamydia trachomatis elementary bodies and ELISA antibody to recombinant chlamydial heat-shock protein 60 (Chsp60) determined. Women were prospectively followed at monthly intervals over 2 years for incident C. trachomatis infection and acute pelvic inflammatory disease (PID). HLA DQA1*0401 and DQB1*0402 alleles were statistically associated with increased prevalence and amount of antibody to Chsp60 but not MIF antibody. However, these alleles did not alter the risk for chlamydial PID. The potential role that HLA DQ may play in chlamydial disease pathogenesis requires further study.

Antibodies, Bacterial↗
PubMed1999

Antibody response to the chlamydial heat-shock protein 60 in an experimental model of chronic pelvic inflammatory disease in monkeys (Macaca nemestrina).

A primate model of chlamydial pelvic inflammatory disease was used to characterize serum antibody responses to the 60 kDa chlamydial heat shock protein (CHSP60). Forty monkeys were infected in the fallopian tubes with Chlamydia trachomatis and then were treated. Twenty-three (58%) monkeys developed antibodies against CHSP60, of whom 6 (15%) had CHSP60 responses that persisted throughout the study and 17 (42.5%) had a transient response. A persistent CHSP60 antibody response was correlated with being culture- or ligase chain reaction-positive in the fallopian tubes (P=.004), but not in the cervix pretreatment, and with being tubal-positive posttreatment (P=. 02). Compared with tubal-negative monkeys, tubal-positive monkeys had more intense CHSP60 responses (P=.006) that lasted longer (P=. 002). Among CHSP60 responders, an OD>0.5 was correlated with more severe salpingeal pathology before treatment (P=.04). CHSP60 antibody response may be useful as a marker of persistent chlamydial infection in the fallopian tubes.

Animals↗