June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Longitudinal study of the Sero-prevalence of pgp3 Antibody to C. trachomatis in a cohort of children in a trachoma endemic area
Author Affiliations & Notes
  • Hemjot Kaur
    Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
  • Beatriz Munoz
    Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
  • Harran Mkocha
    Kongwa Trachoma Project, Dar es Salaam, Tanzania, United Republic of
  • Laura Dize
    SOM Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, United States
  • charlotte gaydos
    SOM Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, United States
  • Sheila West
    Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
  • Footnotes
    Commercial Relationships   Hemjot Kaur, None; Beatriz Munoz, None; Harran Mkocha, None; Laura Dize, None; charlotte gaydos, None; Sheila West, None
  • Footnotes
    Support  International Trachoma Initiative
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4792. doi:
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      Hemjot Kaur, Beatriz Munoz, Harran Mkocha, Laura Dize, charlotte gaydos, Sheila West; Longitudinal study of the Sero-prevalence of pgp3 Antibody to C. trachomatis in a cohort of children in a trachoma endemic area. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4792.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Trachoma is still the leading infectious cause of blindness world-wide, but many countries are reaching elimination targets. Surveillance tools to monitor districts with low prevalence are needed, and testing for antibodies, which may reflect cumulative exposure to infection, may be a useful tool. This study provides the first longitudinal data on stability of the antibodies over time in a cohort of children over one year

Methods : At baseline, a random sample of 51 children ages 1-9 in each of 50 communities was taken, based on a recent census. Both eyes were examined for sings of trachoma using the WHO simplified grading scheme, and an ocular swab was taken for determination of infection using Aptima combo. A finger prick blood sample was taken on a filter paper, dried, and analyzed for pgp3 antibodies using a Luminex 100 platform. Antibody is reported as Minimum Fluorescent Intensity minus Background (MIF-BG) where positivity was determined as above a cut-off using Receiver Operator Curve analyses. One year later, the same children were eligible for follow up and the same procedures performed. No mass drug treatment was provided to these communities in the interim year.

Results : The average community prevalence of trachoma at baseline was 4.7%, ranging from 2.7 to 6.8%; infection prevalence was 4.6%, (range=3.1-6.0%). 83% (2121/2550) of children were followed up. At baseline 69% of children were negative for pgp3 antibodies, and 11% sero-converted over the year. Almost half of the incident cases were ages 1-3 years. Of the 31% who were positive for pgp3 antibodies, 6% reverted to negative at one year; 40% of the sero-reversion cases were age 1-3 years. Overall, 91% of children maintained their baseline antibody status at one year, but we observed cases of infections at baseline that did not sero-convert

Conclusions : In these low prevalence communities, sero-prevalence of pgp3 antibodies in children is reasonably stable over one year. Further work on the relationship of infection to sero-conversion is warranted.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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