The World Health Organization Recommendations for Trachoma Surveillance, Experience in Nepal and Added Benefit of Testing for Antibodies to Chlamydia trachomatis pgp3 Protein: NESTS Study

Zambrano, Andrea; Sharma, Shaveta; Crowley, Kathryn; Dize, Laura; Muñoz, Beatriz; Mishra, Sailesh Kumar; Rotondo, Lisa; Gaydos, Charlotte A.; West, Sheila K.

doi:10.1371/journal.pntd.0005003

Cited by 23 publications

(34 citation statements)

References 8 publications

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“…This increase in seropositivity by age was not as sharp as observed in hyperendemic areas, where virtually everyone over age 6 years was seropositive 9 . It is also in contrast to the collapse of the age specific increase in seroprevalence which has been one of the features of testing in formerly endemic districts where TF has been eliminated 6 , 10 , 11 . While some of the lack of age specific increase in seropositivity has been attributed to the lack of transmission of infection in these areas, it is possible that some of this is due to seroreversion in communities where there is low or absent trachoma.…”

Section: Discussionmentioning

confidence: 95%

“…Details of the processing for the dried blood spots are described elsewhere 8 , 10 and summarized here. Total IgG was detected using biotinylated mouse anti-human total IgG (clone H2; Southern Biotech, Birmingham, AL), IgG4 (clone HP6025; Invitrogen, South San Francisco, CA), and R-phycoerythrin-labeled streptavidin (Invitrogen, South San Francisco, CA).…”

Section: Methodsmentioning

confidence: 99%

“…In that study, the age specific prevalence of seropositivity increased but at a very modest rate. In a surveillance survey in two districts in Nepal, TF and infection were virtually absent and the low antibody seropositivity rate, average 2%, showed no increase with age among 1–9 year olds 10 . Similar findings from cross sectional studies in villages have also been reported 4 , 11 .…”

Section: Introductionmentioning

confidence: 94%

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Longitudinal change in the serology of antibodies to Chlamydia trachomatis pgp3 in children residing in a trachoma area

West

Muñoz

Kaur

et al. 2018

Sci Rep

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A serologic test for antibodies to chlamydial antigen pgp3 may be a useful tool for trachoma surveillance. However, little is known about the stability of antibody status over time, or factors associated with seroreversion/conversion. A cohort of 2,111 children ages 1–9 years in Tanzania were followed for one year in the absence of mass azithromycin. At baseline and follow-up, they were evaluated for trachoma, chlamydial infection, and antibodies to chlamydial antigen pgp3. At baseline, 31% of children were seropositive for pgp3 antibodies and 6.4% seroreverted to negative over one year. Of those seronegative, 9.8% seroconverted over the year. The seroreverters had lower baseline mean fluorescence intensity (MFI-BG) values compared to the seropositives who remained positive (Odds Ratio = 0.04 for every unit increase in log10MFI-BG, 95% CI = 0.02–0.09), and were more likely to live in communities with trachoma <5% (p < 0.008). While seroconversion was expected, seroreversion was unexpected. The low seroprevalence rate reported from low endemic areas may be due to seroreversion as well as lack of exposure.

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Section: Discussionmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

See 1 more Smart Citation

Longitudinal change in the serology of antibodies to Chlamydia trachomatis pgp3 in children residing in a trachoma area

West

Muñoz

Kaur

et al. 2018

Sci Rep

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“…Serological tests for measuring antibodies represents a means for monitoring cumulative exposure to ocular infection in children. 6 – 10 Serological testing would also facilitate integration of trachoma surveillance with other health program activities in which blood collection is occurring, such as demographic and health surveys, malaria indicator surveys, or vaccine-coverage surveys.…”

Section: Introductionmentioning

confidence: 99%

Prevalence of Chlamydia trachomatis-Specific Antibodies before and after Mass Drug Administration for Trachoma in Community-Wide Surveys of Four Communities in Nepal

Gwyn

Xiang

Kandel

et al. 2018

The American Journal of Tropical Medicine and Hygiene

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Abstract.The target end date for the global elimination of trachoma as a public health problem is 2020. As countries begin the process for submitting their dossier for the validation of elimination of trachoma as a public health problem, strategies for post-validation surveillance must be considered. Seroprevalence of antibodies against antigens from the causative bacteria Chlamydia trachomatis (Ct) in young children has been shown to reflect trachomatous inflammation–follicular (TF) rates in both endemic and previously endemic settings. However, none of these studies has directly compared age seroprevalence in the same communities before and after mass drug administration (MDA) for trachoma. Here we report a marked shift in age seroprevalence curves in four villages in Kapilvastu District, Nepal, before and after MDA. Clinical examinations were performed and blood was taken before (N = 659) and 5 years after (N = 646) MDA. Rates of TF decreased from 17.6% in ≤ 9-year-olds before MDA (N = 52) to 0% in ≤ 9-year-olds (N = 73) after MDA. Positive antibody responses to Ct in the entire population decreased from 82.1% pre-MDA to 35.8% post-MDA, whereas those among ≤ 9-year-olds decreased from 59.6% to 4.1%. These data show that the postintervention decrease in TF was reflected in a drop in anti-Ct antibody responses, suggesting that antibody responses could be useful indicators for post-validation surveillance.

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“…Situations such as this highlight the need to develop new tools that can support programmes to make informed decisions about how to use antimicrobials in trachoma control. Antibodies against Chlamydia trachomatis reflect cumulative exposure to Ct 10 , 11 and it has been suggested that programmes could use some measure of seroprevalence as an alternative indicator of changes in transmission 12 , 13 . Previous work has investigated the use of age-specific seroprevalence for surveillance in the peri- 14 and post-MDA setting 13 , 15 , 16 .…”

Section: Introductionmentioning

confidence: 99%

Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia

Migchelsen

Sepúlveda

Martin³

et al. 2017

Preprint

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Trachoma is caused by Chlamydia trachomatis (Ct). It is targeted for global elimination as a public health problem. In 2014, a population-based cross-sectional study was performed in two previously trachoma-endemic areas of The Gambia. Participants of all ages from Lower River Region (LRR) (N = 1028) and Upper River Region (URR) (N = 840) underwent examination for trachoma and had blood collected for detection of antibodies against the Ct antigen Pgp3, by ELISA. Overall, 30 (1.6%) individuals had active trachoma; the prevalence in children aged 1–9 years was 3.4% (25/742) with no statistically significant difference in prevalence between the regions. There was a significant difference in overall seroprevalence by region: 26.2% in LRR and 17.1% in URR (p<0.0001). In children 1-9 years old, seroprevalence was 4.4% in LRR and 3.9% in URR. Reversible catalytic models using information on age-specific seroprevalence demonstrated a decrease in the transmission of Ct infection in both regions, possibly reflecting the impact of improved access to water, health and sanitation as well as mass drug administration campaigns. Serological testing for antibodies to Ct antigens is potentially useful for trachoma programmes, but consideration should be given to the coendemicity of sexually transmitted Ct infections.

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The World Health Organization Recommendations for Trachoma Surveillance, Experience in Nepal and Added Benefit of Testing for Antibodies to Chlamydia trachomatis pgp3 Protein: NESTS Study

Cited by 23 publications

References 8 publications

Longitudinal change in the serology of antibodies to Chlamydia trachomatis pgp3 in children residing in a trachoma area

Longitudinal change in the serology of antibodies to Chlamydia trachomatis pgp3 in children residing in a trachoma area

Prevalence of Chlamydia trachomatis-Specific Antibodies before and after Mass Drug Administration for Trachoma in Community-Wide Surveys of Four Communities in Nepal

Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia

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