A multicenter evaluation of a new antibody test kit for lymphatic filariasis employing recombinant Brugia malayi antigen Bm-14.
Antibody tests are useful for mapping the distribution of lymphatic filariasis (LF) in countries and regions and for monitoring progress in elimination programs based on mass drug administration (MDA). Prior antibody tests have suffered from poor sensitivity and/or specificity or from a lack of standardization. We conducted a multicenter evaluation of a new commercial ELISA that detects IgG4 antibodies to the recombinant filarial antigen Bm14. Four laboratories tested a shared panel of coded serum or plasma samples that included 55 samples from people with microfilaremic Wuchereria bancrofti or Brugia infections and 26 control samples. Qualitative results were identical in all four test sites. In addition, each laboratory tested samples from their own serum banks. The test detected antibodies in 32 of 36 samples (91%) from people with Brugian filariasis and in 96 of 98 samples (98%) from people with Bancroftian filariasis. Specificity testing showed that many serum or plasma samples from patients with other filarial infections such as onchocerciasis had positive antibody tests. Specificity was otherwise excellent, although 3 of 30 samples from patients with ascariasis and 4 of 51 with strongyloidiasis had positive antibody tests; it is likely that some or all of these people had previously lived in filariasis-endemic areas. Antibody test results obtained with eluates from blood dried on filter paper were similar to those obtained with plasma tested at the same dilution. This test may be helpful for diagnosing LF in patients with clinical signs of filariasis. It may also be a useful tool for use in LF endemic countries to monitor the progress of filariasis elimination programs and for post-MDA surveillance.
Weil
Gary J
GJ
Infectious Diseases Division, Washington University School of Medicine, St Louis, MO, USA. gweil@dom.wustl.edu
Curtis
Kurt C
KC
Fischer
Peter U
PU
Won
Kimberly Y
KY
Lammie
Patrick J
PJ
Joseph
Hayley
H
Melrose
Wayne D
WD
Brattig
Norbert W
NW
D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000276:immunology*; D017178:Brugia malayi / Q000276:immunology*; D004605:Elephantiasis, Filarial / Q000175:diagnosis* / Q000469:parasitology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015801:Helminth Proteins / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D011933:Reagent Kits, Diagnostic; D011994:Recombinant Proteins / Q000276:immunology*; D012680:Sensitivity and Specificity
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D015801:Helminth Proteins; D007074:Immunoglobulin G; D011933:Reagent Kits, Diagnostic; D011994:Recombinant Proteins