Spontaneous Antigenemia in Loiasis

Spontaneous Antigenemia in Loiasis, A Study of the Loiasis Antigens Responsible for Cross-reactivity in the Rapid Diagnostic Test for Lymphatic Filariasis

This prospective study will enroll and follow 60 loiasis patients with high worm burden to monitor the spontaneous release of filarial antigen in peripheral blood. This study will define the cross-reactive antigen profile of persons with spontaneous loiasis antigenemia, and determine whether it varies with time.

Global efforts to eradicate lymphatic filariasis (LF) depend on rapid diagnostic tests (RDTs) that detect Wuchereria bancrofti circulating filarial antigen but these tests are unreliable in African nations where Loa loa is co-endemic because they yield false-positive results in some individuals with loiasis. The goals of this project are to define the cross-reactive antigen profile of persons with spontaneous antigenemia, how it varies over time, and to determine which L. loa antigens in cross-reactive sera best distinguish loiasis cross-reactivity from LF.

This prospective study will prospectively enroll 50 adults who presented with cross-reactive antigenemia at screening and 10 negative controls. Participants will followed for one year and tested every three months for persistence of antigenemia.

Inclusion Criteria:

• Ability to give informed consent
• Loiasis Mf count > 20,000 Mf/mL
• Resident of study area
• No evidence of severe or systemic comorbidities
• Consent to storage of blood samples for future study

Exclusion Criteria:

• Subject plans to move from the study area during subsequent 12 months