Seroconversion Rate for Post-Validation Surveillance of Trachoma Open Access
Randall, Jessica (Spring 2019)
Abstract
Purpose: The WHO is considering the utility of serological surveillance for trachoma. If comparable to clinical diagnoses, this type of surveillance would be a cost-effective and sustainable solution. Our serological survey from two districts in The Republic of Togo, a country now known to have reached the threshold for elimination of trachoma as a public health problem, supports the use of a seroconversion rate as an estimate of force of infection in non-endemic areas.
Methods: We conducted serological surveillance on 2915 participants 1-9 years old in two districts purposefully selected as the most likely to have trachoma if it would be in the country at all. Each participant had a finger-prick blood sample collected onto filter paper. We fit a logistic regression model to estimate seroprevalence. Participants had blood collected to measure antibody responses to the C. trachomatis (CT) antigens Pgp3 and Ct694 by multiplex bead-based immunoassay (MBA), the lab-based dipstick Pgp3 lateral flow assay (LFA), and the field based cassette Pgp3 lateral flow assay.We calculated a seroconversion rate for each antigen by fitting a reversible serocatalytic model which assumes zero seroreversion. We report median fluorescence intensity-background (MFI-BG ), seroprevalence, age-specific seroprevalence and seroconversion rate.
Results: Out of 2915 samples, 96% were negative by the MBA and LFA. Age-specific seroprevalence was estimated using a logistic regression model. Mean SCRs for each antigen and assay method were estimated by taking the mean of each age-specific seroconversion rate.
Conclusions: Our results support those of a parent study that found that the clinical diagnosis of trachoma, trachomatous inflammation- follicular (TF) falls below the 5% WHO threshold of elimination of trachoma as a public health problem. Our calculation of a seroconversion rate, an estimation of the force of infection, indicated no active transmission.
Table of Contents
Introduction: ........................................................................................................................1
Methods: ..............................................................................................................................3
Results: ................................................................................................................................6
Discussion: ...........................................................................................................................8
Conclusions and Recommendations: ..................................................................................... 10
References: ..........................................................................................................................11
Tables and Figures: ...............................................................................................................13
Appendix…………………………………………………………………….…………...................................15
About this Master's Thesis
- Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School | |
---|---|
Department | |
Degree | |
Submission | |
Language |
|
Research Field | |
Keyword | |
Committee Chair / Thesis Advisor | |
Committee Members | |
Partnering Agencies |
Primary PDF
Thumbnail | Title | Date Uploaded | Actions |
---|---|---|---|
|
Seroconversion Rate for Post-Validation Surveillance of Trachoma () | 2019-04-18 12:42:43 -0400 |
|
Supplemental Files
Thumbnail | Title | Date Uploaded | Actions |
---|---|---|---|
![]() |
SAS Code (SAS code for analysis in the project) | 2019-04-18 12:42:46 -0400 |
|
![]() |
Python Code (Python code for all graphs used in thesis) | 2019-04-18 12:42:50 -0400 |
|
|
Jupyter Notebook (Jupyter Notebook of Python code of Graphs) | 2019-04-18 12:42:54 -0400 |
|