Dataset Information

Community-level chlamydial serology for assessing trachoma elimination in trachoma-endemic Niger.

ABSTRACT: BACKGROUND:Program decision-making for trachoma elimination currently relies on conjunctival clinical signs. Antibody tests may provide additional information on the epidemiology of trachoma, particularly in regions where it is disappearing or elimination targets have been met. METHODS:A cluster-randomized trial of mass azithromycin distribution strategies for trachoma elimination was conducted over three years in a mesoendemic region of Niger. Dried blood spots were collected from a random sample of children aged 1-5 years in each of 24 study communities at 36 months after initiation of the intervention. A multiplex bead assay was used to test for antibodies to two Chlamydia trachomatis antigens, Pgp3 and CT694. We compared seropositivity to either antigen to clinical signs of active trachoma (trachomatous inflammation-follicular [TF] and trachomatous inflammation-intense [TI]) at the individual and cluster level, and to ocular chlamydia prevalence at the community level. RESULTS:Of 988 children with antibody data, TF prevalence was 7.8% (95% CI 6.1 to 9.5) and TI prevalence was 1.6% (95% CI 0.9 to 2.6). The overall prevalence of antibody positivity to Pgp3 was 27.2% (95% CI 24.5 to 30), and to CT694 was 23.7% (95% CI 21 to 26.2). Ocular chlamydia infection prevalence was 5.2% (95% CI 2.8 to 7.6). Seropositivity to Pgp3 and/or CT694 was significantly associated with TF at the individual and community level and with ocular chlamydia infection and TI at the community level. Older children were more likely to be seropositive than younger children. CONCLUSION:Seropositivity to Pgp3 and CT694 correlates with clinical signs and ocular chlamydia infection in a mesoendemic region of Niger. TRIAL REGISTRATION:ClinicalTrials.gov NCT00792922.

SUBMITTER: Kim JS

PROVIDER: S-EPMC6366708 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Community-level chlamydial serology for assessing trachoma elimination in trachoma-endemic Niger.

Kim Jessica S JS Oldenburg Catherine E CE Cooley Gretchen G Amza Abdou A Kadri Boubacar B Nassirou Baido B Cotter Sun Yu SY Stoller Nicole E NE West Sheila K SK Bailey Robin L RL Keenan Jeremy D JD Gaynor Bruce D BD Porco Travis C TC Lietman Thomas M TM Martin Diana L DL

PLoS neglected tropical diseases 20190128 1

<h4>Background</h4>Program decision-making for trachoma elimination currently relies on conjunctival clinical signs. Antibody tests may provide additional information on the epidemiology of trachoma, particularly in regions where it is disappearing or elimination targets have been met.<h4>Methods</h4>A cluster-randomized trial of mass azithromycin distribution strategies for trachoma elimination was conducted over three years in a mesoendemic region of Niger. Dried blood spots were collected fro ...[more]

PMID: 30689671

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Project description:BackgroundTrachoma, caused by Chlamydia trachomatis (Ct), is the leading infectious cause of blindness worldwide. Yearly azithromycin mass drug administration (MDA) plays a central role in efforts to eliminate blinding trachoma as a public health problem. Programmatic decision-making is currently based on the prevalence of the clinical sign "trachomatous inflammation-follicular" (TF) in children. We sought to test alternative tools for trachoma surveillance based on serology in the 12-year cohort of Kahe Mpya, Rombo District, Tanzania, where ocular chlamydial infection was eliminated with azithromycin MDA by 2005.Methodology and principal findingsThe present study was a community-based cross-sectional survey in Kahe Mpya. Of 989 residents, 571 people aged 6 months to 87 years were enrolled: 58% of the total population and 73% of 1-9 year olds, the key WHO indicator age group. Participants were examined for TF, had conjunctival swabs collected for nucleic acid amplification test (NAAT)-based detection of Ct, and blood collected for analysis of antibodies to the Ct antigens pgp3 and CT694 by multiplex bead-based immunoassay. Seroconversion rate was used to estimate changes in the force of infection in a reversible catalytic model. No conjunctival swabs tested positive for Ct infection by NAAT. Among 1-9 year olds, TF prevalence was 6.5%, whereas only 3.5% were seropositive. Force of infection modelling indicated a 10-fold decrease in seroconversion rate at a time corresponding to MDA commencement. Without baseline serological data, the inferences we can make about antibody status before MDA and the longevity of the antibody response are limited, though our use of catalytic modelling overcomes some of these limitations.Conclusions/significanceSerologic tests support NAAT findings of very low to zero prevalence of ocular Ct in this community and have potential to provide objective measures of transmission and useful surveillance tools for trachoma elimination programs.

Project description:Trachoma control programs utilize mass azithromycin distributions to treat ocular Chlamydia trachomatis as part of an effort to eliminate this disease world-wide. But it remains unclear what the community-level risk factors are for infection.This cluster-randomized, controlled trial entered 48 randomly selected communities in a 2×2 factorial design evaluating the effect of different treatment frequencies and treatment coverage levels. A pretreatment census and examination established the prevalence of risk factors for clinical trachoma and ocular chlamydia infection including years of education of household head, distance to primary water source, presence of household latrine, and facial cleanliness (ocular discharge, nasal discharge, and presence of facial flies). Univariate and multivariate associations were tested using linear regression and Bayes model averaging.There were a total of 24,536 participants (4,484 children aged 0-5 years) in 6,235 households in the study. Before treatment in May to July 2010, the community-level prevalence of active trachoma (TF or TI utilizing the World Health Organization [WHO] grading system) was 26.0% (95% CI: 21.9% to 30.0%) and the mean community-level prevalence of chlamydia infection by Amplicor PCR was 20.7% (95% CI: 16.5% to 24.9%) in children aged 0-5 years. Univariate analysis showed that nasal discharge (0.29, 95% CI: 0.04 to 0.54; P?=?0.03), presence of flies on the face (0.40, 95% CI: 0.17 to 0.64; P?=?0.001), and years of formal education completed by the head of household (0.07, 95% CI: 0.07 to 0.13; P?=?0.03) were independent risk factors for chlamydia infection. In multivariate analysis, facial flies (0.26, 95% CI: 0.02 to 0.49; P?=?0.03) and years of formal education completed by the head of household (0.06, 95% CI: 0.008 to 0.11; P?=?0.02) were associated risk factors for ocular chlamydial infection.We have found that the presence of facial flies and years of education of the head of the household are risk factors for chlamydia infection when the analysis is done at the community level.ClinicalTrials.gov NCT00792922.

Project description:BackgroundMass drug administration with antibiotics predominantly with azithromycin is one of the four arms of the SAFE strategy. The elimination of ocular chlamydial infection is only achieved as long as the azithromycin mass treatments (AMT) are given frequently enough and at a high enough coverage. This study was conducted to assess the coverage of azithromycin mass treatment and its determinants in Awi Zone, Northwestern Ethiopia.MethodsHouse to house survey using a structured questionnaire was done between July 7 to July 25, 2013. Coverage is defined as the proportion of individuals in the eligible population who actually ingested the Azithromycin during the Campaign.ResultsA total of 1267 households were enrolled in the survey in which 5826 eligible members were living in these households. Almost half (54.6%) of the community members who were eligible for all six campaigns had participated in more than three campaigns of azithromycin mass treatment. The overall average self-reported coverage of the azithromycin mass treatment (AMT) in all six campaigns was 62.8% (64% in rural vs. 61.6% urban). On average, each eligible person had taken the drug 3.77 times. The rural residents were significantly more likely to have received treatment during the last round of AMT in 2012 {AOR?=?2.35; 95% CI [1.80-3.06]}. Azithromycin uptake status of female household heads was less than the corresponding male household heads {AOR?=?0.41; 95% CI [0.24-0.72]}. Household heads' awareness about trachoma (AOR?=?2.55; 95% CI [1.19-5.44]) and AMT {AOR?=?7.19; 95% CI [3.27-15.82]} had positive association with acceptability.ConclusionThe overall average AMT coverage was found to be low. There was low coverage of the treatment in the urban community as compared to the rural residents. Misconceptions of household heads about trachoma and azithromycin have negatively affected the coverage. Further work on why female household heads are associated with higher risk of non-participation in AMT is warranted. Strengthening awareness creation and consideration of additional campaigns is essential.

Project description:BackgroundTo eliminate trachoma as a public health problem, countries must achieve a district-level prevalence of trachomatous inflammation-follicular (TF) <5% in children ages 1-9 years. Re-emergence of TF could trigger additional rounds of mass drug/antibiotic administration (MDA), so accurate tools for use in surveys assessing trachoma prevalence are essential.Methodology & principal findingsWe surveyed 2401 children ages 1-9 years from 50 villages in Kongwa, Tanzania, 2 years post-MDA and 1.5 years after an impact survey found TF <5% in the same villages. Our survey included multiple tools: clinical determination of TF, Cepheid testing for Chlamydia trachomatis infection, and testing for anti-pgp3 antibodies via multiplex bead array. Photographs of the upper tarsal conjunctiva were taken in a subset of children to corroborate the field grades. Overall TF prevalence in 1-9 year olds was 7.1% (95% CI: 5.6%-8.9%), which decreased with age (p = <0.0001). TF prevalence by village was heterogeneous, with 19 villages having TF <5% and 16 villages having TF >10%. There was a strong correlation between field and photo grading of TF (kappa = 0.69; 95% CI: 0.60-0.78) and between TF and infection, with 21.5% of TF-positive children also testing positive for infection, as compared to only 1.6% of TF-negative children (p = 0.0010). Overall seroprevalence was 18.2% (95% CI: 14.8%-22.1%), which increased with age (p = <0.0001). Notably, 1-2 year olds, who were born after the cessation of MDA and theoretically should not have had exposure to C. trachomatis in the absence of transmission, had an average seroprevalence of 6.7%.Conclusions & significanceField TF prevalence, supported by photographic review and infection data, suggested re-emergence of trachoma in Kongwa. Moreover, seropositivity in the children born after cessation of MDA indicated exposure to C. trachomatis despite a previous survey finding of TF <5%. Examining seropositivity in specific age groups expected to have limited exposure to C. trachomatis can be used to detect re-emergence.

Dataset Information

Community-level chlamydial serology for assessing trachoma elimination in trachoma-endemic Niger.

Publications

Community-level chlamydial serology for assessing trachoma elimination in trachoma-endemic Niger.

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