Multicentre evaluations of two new rapid IgG4 tests (WB rapid and panLF rapid) for detection of lymphatic filariasis

Abstract

In the global effort to eliminate lymphatic filariasis (LF), rapid field-applicable tests are useful tools that will allow on-site testing to be performed in remote places and the results to be obtained rapidly. Exclusive reliance on the few existing tests may jeopardize the progress of the LF elimination program, thus the introduction of other rapid tests would be useful to address this issue. Two new rapid immunochromatographic IgG4 cassette tests have been produced, namely WB rapid and panLF rapid, for detection of bancroftian filariasis and all three species of lymphatic filaria respectively. WB rapid was developed using BmSXP recombinant antigen, while PanLF rapid was developed using BmR1 and BmSXP recombinant antigens. A total of 165 WB rapid and 276 panLF rapid tests respectively were evaluated at USM and the rest were couriered to another university in Malaysia (98 WB rapid, 129 panLF rapid) and to universities in Indonesia (56 WB rapid, 62 panLF rapid), Japan (152 of each test) and India (18 of each test) where each of the tests underwent independent evaluations in a blinded manner. The average sensitivities of WB rapid and panLF rapid were found to be 97.6% (94%-100%) and 96.5% (94%-100%) respectively; while their average specificities were both 99.6% (99%-100%). Thus this study demonstrated that both the IgG4 rapid tests were highly sensitive and specific, and would be useful additional tests to facilitate the global drive to eliminate this disease.

Quantifying the Influence of Larval Density on Disease Transmission Indices in Culex quinquefasciatus, the Major African Vector of Filariasis

“…For example, the result revealed that at the highest density treatment, longevity was <3 days; these cohorts may not be, epidemiologically, important in disease transmission, as filarial parasites spend about 10 days within the mosquito to reach infective stage. 2,3,69,70 The reverse can be said for cohorts raised at lower density regimen, especially at 1 larva/10 mL. Further studies are advocated to verify the role of density regimens on vector–parasite interaction.…”

“…Hence, the World Health Organization (WHO) recommended mosquito-vector control as a supplemental strategy for eliminating the disease. 2,3 However, effective mosquito-vector control must be predicated on an adequate knowledge of the ecophysiology of the vector species. Ecological interaction among immature mosquitoes is of particular importance as they affect egg hatching, 4 competition, and abundance.…”

A novel rapid test for detecting antibody responses to Loa loa infections

“…The test presented herein complements the immunoassays commercialized by others to detect serological responses to onchocerciasis and lymphatic filariasis [ 28 ]. These include antibody-based lateral flow assays specific for Ov16 (Alere, Waltham, USA [ 29 ]), Wb123 (Alere, [ 29 ]), Bm14 (Brugia Rapid; Reszon, Selangor, Malaysia, [ 30 ]) and Bm14+R1 (PanLF Rapid, Reszon [ 30 ]), and ELISA assays for Wb123 (InBios, Seattle, USA) and Bm14 (Cellabs, Brookvale, Australia [ 27 ]). Antigen-based tests remain much needed and currently exist only for lymphatic filariasis, where they detect circulating filarial antigen (CFA) on a rapid point-of-care platform (BinaxNOW Filariasis [ 31 ] and Filariasis Test Strip (FTS) [ 32 ], both by Alere) or by ELISA (TropBio Og4C3, Cellabs [ 33 ]).…”

Regulatory T Cell Subsets in Filarial Infection and Their Function

“…In fact, it has been shown that patent filarial infection is characterized by a modified Th2 response that is associated with increased frequencies of IL-4- and IL-10-producing CD4 T cells (70, 95). Moreover, IgG4 has been used as a marker of filarial infection diagnosis but also as a marker of immunoregulation (96, 97). Although direct evidence for filarial-induced IL-10 to be involved in the induction of IgG4 class switching has not been established, it has been shown that IL-10 can act on human B cells and induce the production of IgG4 (98, 99).…”