Ameyo Monique Dorkenoo1,2, Adjaho Koba3, Wemboo A Halatoko3, Minongblon Teko3, Komlan Kossi3, Kossi Yakpa4, Rachel N Bronzan5. 1. Faculté des Sciences de la Santé, Université de Lomé, Boulevard Eyadema, 01BP 1515, Lomé, Togo. monicadork@yahoo.fr. 2. Ministère de la Santé et de l'Hygiène Publique Togo, Angle Avenue Sarakawa et Avenue du 24 Janvier, 01BP 336, Lomé, Togo. monicadork@yahoo.fr. 3. Institut National d'Hygiène, 1 Rue Namgbeto, Quartier administratif, 01BP 1396, Lomé, Togo. 4. Ministère de la Santé et de l'Hygiène Publique Togo, Angle Avenue Sarakawa et Avenue du 24 Janvier, 01BP 336, Lomé, Togo. 5. Health and Development International, 8 Essex St, Newburyport, MA, USA.
Abstract
BACKGROUND: The World Health Organization has targeted lymphatic filariasis (LF) for elimination as a public health problem and recommends, among other measures, post-elimination surveillance of LF. The identification of sensitive and specific surveillance tools is therefore a research priority. The Wuchereria bancrofti-specific antigen Wb123-based enzyme-linked immunosorbent assay (Wb123 ELISA) detects antibodies to the recombinant Wb123 antigen of W. bancrofti and may be useful as a surveillance tool for LF. Six years after stopping mass drug administration to eliminate LF and recording successful results on two post-treatment transmission assessment surveys, a study was conducted in Togo aimed at helping to identify the role of the Wb123 ELISA in post-validation surveillance of LF. METHODS: This was a cross-sectional study in eight previously LF-endemic districts and one non-endemic district in Togo. In each sub-district of these nine districts, two schools were selected and 15 children aged 6 to 9 years old at each school provided finger-stick blood for testing for antibodies to Wb123 using the Filaria Detect™ IgG4 ELISA kit® (InBios, International, Inc., Seattle, WA, USA). RESULTS: A total of 2654 children aged 6 to 9 years old were tested in 134 schools in the nine districts. Overall, 4.7% (126/2654) children tested positive for antibodies to the Wb123 antigen of W. bancrofti. The prevalence of Wb123 antibodies varied across the eight previously endemic LF districts, from 1.56 to 6.62%. The highest prevalence, 6.99%, was found in the non-endemic district, but this was not significantly different from the average of all the LF districts (4.49%, P = 0.062). CONCLUSIONS: The Wb123 ELISA was positive in 4.7% of Togolese school-age children who were almost certainly unexposed to LF. This apparent lack of specificity in the Togo context makes it difficult to establish a seroprevalence threshold that could serve to signal LF resurgence in the country, precluding the use of this test for post-validation surveillance in Togo. There remains a need to develop a useful and reliable test for post-elimination surveillance for LF in humans.
BACKGROUND: The World Health Organization has targeted lymphatic filariasis (LF) for elimination as a public health problem and recommends, among other measures, post-elimination surveillance of LF. The identification of sensitive and specific surveillance tools is therefore a research priority. The Wuchereria bancrofti-specific antigen Wb123-based enzyme-linked immunosorbent assay (Wb123 ELISA) detects antibodies to the recombinant Wb123 antigen of W. bancrofti and may be useful as a surveillance tool for LF. Six years after stopping mass drug administration to eliminate LF and recording successful results on two post-treatment transmission assessment surveys, a study was conducted in Togo aimed at helping to identify the role of the Wb123 ELISA in post-validation surveillance of LF. METHODS: This was a cross-sectional study in eight previously LF-endemic districts and one non-endemic district in Togo. In each sub-district of these nine districts, two schools were selected and 15 children aged 6 to 9 years old at each school provided finger-stick blood for testing for antibodies to Wb123 using the Filaria Detect™ IgG4 ELISA kit® (InBios, International, Inc., Seattle, WA, USA). RESULTS: A total of 2654 children aged 6 to 9 years old were tested in 134 schools in the nine districts. Overall, 4.7% (126/2654) children tested positive for antibodies to the Wb123 antigen of W. bancrofti. The prevalence of Wb123 antibodies varied across the eight previously endemic LF districts, from 1.56 to 6.62%. The highest prevalence, 6.99%, was found in the non-endemic district, but this was not significantly different from the average of all the LF districts (4.49%, P = 0.062). CONCLUSIONS: The Wb123 ELISA was positive in 4.7% of Togolese school-agechildren who were almost certainly unexposed to LF. This apparent lack of specificity in the Togo context makes it difficult to establish a seroprevalence threshold that could serve to signal LF resurgence in the country, precluding the use of this test for post-validation surveillance in Togo. There remains a need to develop a useful and reliable test for post-elimination surveillance for LF in humans.
Authors: Dziedzom Komi de Souza; Irene Offei Owusu; Joseph Otchere; Michelle Adimazoya; Kwadwo Frempong; Collins Stephen Ahorlu; Daniel Adjei Boakye; Michael David Wilson Journal: Pan Afr Med J Date: 2017-05-29
Authors: Kimberly Y Won; Katherine Gass; Marco Biamonte; Daniel Argaw Dagne; Camilla Ducker; Christopher Hanna; Achim Hoerauf; Patrick J Lammie; Sammy M Njenga; Rahmah Noordin; Kapa D Ramaiah; Reda Ramzy; Ronaldo G Carvalho Scholte; Anthony W Solomon; Ashley A Souza; Jordan Tappero; Emily Toubali; Gary J Weil; Steven A Williams; Jonathan D King Journal: PLoS Negl Trop Dis Date: 2021-11-15