Lymphatic filariasis (LF) is a neglected tropical disease affecting roughly 50 million people worldwide. LF, which is most common in Africa and southeast Asia, is a vector-borne, filarial disease spread through bites from infected mosquitos. LF can cause serious, disfiguring symptoms such as lymphedema and elephantiasis.
The World Health Organization has committed to eliminating LF and has indicated that interrupting disease transmission is possible with Mass Drug Administration (MDA). MDA has been successfully implemented in many countries, and several have achieved elimination. The worldwide prevalence of LF has significantly declined over the years due to the success of these programs. However, some countries are experiencing continued transmission and even disease recrudescence despite years of MDA.
Transmission Assessment Surveys (TAS) are used to determine if there is evidence that transmission has been interrupted and MDA can be stopped. Current diagnostic tools for LF are not perfect because the filarial worms have a complex life cycle that can result in delayed or inaccurate diagnosis. For TAS, filarial test strips (FTS) detect antigen in a finger prick blood sample and are used for rapid diagnoses. These tests are convenient and effective, but may be unable to discriminate between active and historic infection in adults, and do not signify active transmission.
Antibody data has recently become more popular for diagnosing NTDs because it can detect new infections sooner than traditional antigen testing. This thesis examined whether LF antibody data corroborated FTS antigen data, or if cases were possibly being missed by antigen tests alone. Results from TAS-2 data from American Samoa, Philippines, and Tanzania suggested that FTS may be missing new infections. Additionally, using all ages combined masked individual age group effects, so keeping age groups separate may be beneficial. Antibody prevalence is not a good predictor of FTS prevalence at the individual level and the two are not significantly correlated at the cluster level. The datasets were not perfect and the antibody positive/negative cutoffs could be called into question. More analyses should be conducted on other TAS datasets to corroborate and expand on these results.
Table of Contents
Table of Contents
Chapter 1. Introduction and statement of and context for the problem and purpose
Chapter 2. Literature Review
Chapter 3. Methodology
Chapter 4. Results
Chapter 5. Conclusions, Implications, and Recommendations
About this Master's Thesis
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|Evaluating lymphatic filariasis antigen and antibody results from TAS-2 surveys in American Samoa, Philippines, and Tanzania ()||2022-07-25 15:47:27 -0400||