Volume 95, Issue 6
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Since the mid-2000s, the immunochromatographic card test (ICT), a point-of-care test for detecting circulating filarial antigens (CFAs), has been the backbone for mapping and monitoring lymphatic filariasis (LF) worldwide. Recently, there have been instances in which CFA positivity has been associated with microfilaremia. Here, we examined the association, at both the community and individual levels, between and CFA using additional diagnostic tools (quantitative polymerase chain reaction [qPCR], Og4C3 enzyme-linked immunosorbent assay, and IgG4 antibodies to Wb123 assays) to demonstrate the relationship between microfilaremia and ICT positivity. In May 2013, peripheral blood was collected during the day from 1,812 individuals living in southern Cameroon. ICT tests were done on the spot, and positive individuals were resampled at night. Results of qPCR and Wb123 assays concurred proving the absence of infection. Og4C3 assays indicate a quantitative relationship between the level of microfilaremia and that of CFA. This was confirmed by epidemiological analyses, which reveal a strong association between microfilaremia and ICT positivity, with 50% of ICT reacting to when its microfilarial density exceeds 30,000 microfilariae/mL. At the community level, the proportion of positive ICT would exceed 2% when the prevalence of microfilaremia in the total population is above 20%. This has significant implications in terms of mapping and control of LF caused by in -endemic areas. Cross-reactivity of ICT with has to be considered in the context of both individual and community diagnostics.

[open-access] This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...



  1. Rebollo M, Sime H, Assefa A, Cano J, Deribe K, Gonzalez-Escalada A, Shafi O, Davey G, Brooker SJ, Kebede A, Bockarie MJ, , 2015. Shrinking the lymphatic filariasis map of Ethiopia: reassessing the population at risk through nationwide mapping. PLoS Negl Trop Dis 9: e0004172.[Crossref] [Google Scholar]
  2. Bockarie MJ, Rebollo MP, , 2016. Reducing the population requiring interventions against lymphatic filariasis in Africa. Lancet Glob Health 4: e154e155.[Crossref] [Google Scholar]
  3. Nana-Djeunga HC, Tchatchueng-Mbougua JB, Bopda J, Mbickmen-Tchana S, Elong-Kana N, Nnomzo'o E, Akame J, Tarini A, Zhang Y, Njiokou F, Kamgno J, , 2015. Mapping of bancroftian filariasis in Cameroon: prospects for elimination. PLoS Negl Trop Dis 9: e0004001.[Crossref] [Google Scholar]
  4. Bakajika DK, Nigo MM, Lotsima JP, Masikini GA, Fischer K, Lloyd MM, Weil GJ, Fischer PU, , 2014. Filarial antigenemia and Loa loa night blood microfilaremia in an area without bancroftian filariasis in the Democratic Republic of Congo. Am J Trop Med Hyg 91: 11421148.[Crossref] [Google Scholar]
  5. Wanji S, Amvongo-Adjia N, Koudou B, Njouendou AJ, Chounna Ndongmo PW, Kengne-Ouafo JA, Datchoua-Poutcheu FR, Fovennso BA, Tayong DB, Fombad FF, Fischer PU, Enyong PI, Bockarie M, , 2015. Cross-reactivity of filariais ICT cards in areas of contrasting endemicity of Loa loa and Mansonella perstans in Cameroon: implications for shrinking of the lymphatic filariasis map in the central African region. PLoS Negl Trop Dis 9: e0004184.[Crossref] [Google Scholar]
  6. Wanji S, Amvongo-Adjia N, Njouendou AJ, Kengne-Ouafo JA, Ndongmo WPC, Fombad FF, Koudou B, Enyong PA, Bockarie M, , 2016. Further evidence of the cross-reactivity of the Binax NOW® Filariasis ICT cards to non-Wuchereria bancrofti filariae: experimental studies with Loa loa and Onchocerca ochengi . Parasit Vectors 9: 267.[Crossref] [Google Scholar]
  7. Kubofcik J, Fink DL, Nutman TB, , 2012. Identification of Wb123 as an early and specific marker of Wuchereria bancrofti infection. PLoS Negl Trop Dis 6: e1930e1938.[Crossref] [Google Scholar]
  8. Steel C, Kubofcik J, Ottesen EA, Nutman TB, , 2012. Antibody to the filarial antigen Wb123 reflects reduced transmission and decreased exposure in children born following single mass drug administration (MDA). PLoS Negl Trop Dis 6: e1940.[Crossref] [Google Scholar]
  9. Steel C, Golden A, Kubofcik J, LaRue N, de los Santos T, Domingo GJ, Nutman TB, , 2013. Rapid Wuchereria bancrofti-specific antigen Wb123-based IgG4 immunoassays as tools for surveillance following Mass Drug Administration Programs on lymphatic filariasis. Clin Vaccine Immunol 20: 11551161.[Crossref] [Google Scholar]
  10. Chesnais CB, Missamou F, Pion SDS, Bopda J, Louya F, Majewski AC, Weil GJ, Boussinesq M, , 2013. Semi-quantitative scoring of an immunochromatographic test for circulating filarial antigen. Am J Trop Med Hyg 89: 916918.[Crossref] [Google Scholar]
  11. Rao RU, Atkinson LJ, Ramzy RMR, Helmy H, Farid HA, Bockarie MJ, Susapu M, Laney SJ, Williams SA, Weil GJ, , 2006. A real-time PCR-based assay for detection of Wuchereria bancrofti DNA in blood and mosquitoes. Am J Trop Med Hyg 74: 826832. [Google Scholar]
  12. Fink DL, Kamgno J, Nutman TB, , 2011. Rapid molecular assays for specific detection and quantitation of Loa loa microfilaremia. PLoS Negl Trop Dis 5: e1299.[Crossref] [Google Scholar]
  13. Drame PM, Montavon C, Pion SD, Kubofcik J, Fay MP, Nutman TB, , 2016. Molecular epidemiology of blood-borne human parasites in a Loa loa-, Mansonella perstans-, and Plasmodium falciparum-endemic region of Cameroon. Am J Trop Med Hyg 94: 13011308.[Crossref] [Google Scholar]
  14. Steel C, Golden A, Stevens E, Yokobe L, Domingo GJ, de los Santos T, Nutman TB, , 2015. Rapid point-of-contact tool for mapping and integrated surveillance of Wuchereria bancrofti and Onchocerca volvulus infection. Clin Vaccine Immunol 22: 896901.[Crossref] [Google Scholar]
  15. Weil GJ, Liftis F, , 1987. Identification and partial characterization of a parasite antigen in sera from humans infected with Wuchereria bancrofti . J Immunol 138: 30353041. [Google Scholar]
  16. Weil GJ, Jain DC, Santhanam S, Malhotra A, Kumar H, Sethumadhavan KV, Liftis F, Ghosh TK, , 1987. A monoclonal antibody-based enzyme immunoassay for detecting parasite antigenemia in bancroftian filariasis. J Infect Dis 156: 350355.[Crossref] [Google Scholar]
  17. More SJ, Copeman DB, , 1990. A highly specific and sensitive monoclonal antibody-based ELISA for the detection of circulating antigen in bancroftian filariasis. Trop Med Parasitol 41: 403406. [Google Scholar]
  18. Bloch P, Simonsen PE, Weiss N, Nutman TB, , 1998. The significance of guinea worm infection in the immunological diagnosis of onchocerciasis and bancroftian filariasis. Trans R Soc Trop Med Hyg 92: 518521.[Crossref] [Google Scholar]
  19. Garcia A, Abel L, Cot M, Richard P, Ranque S, Feingold J, Demenais F, Boussinesq M, Chippaux JP, , 1999. Genetic epidemiology of host predisposition microfilaraemia in human loiasis. Trop Med Int Health 4: 565574.[Crossref] [Google Scholar]
  20. World Health Organization, 2011. Monitoring and Epidemiological Assessment of Mass Drug Administration in the Global Programme to Eliminate Lymphatic Filariasis: A Manual for National Elimination Programmes. WHO/HTM/NTD/PCT/2011.4. Geneva, Switzerland: World Health Organization. [Google Scholar]
  21. World Health Organization, 2012. Provisional Strategy for Interrupting Lymphatic Filariasis Transmission in Loiasis-Endemic Countries. Report of the Meeting on Lymphatic Filariasis, Malaria and Integrated Vector Management. WHO/HTM/NTD/PCT/2012.6. Geneva, Switzerland: World Health Organization. [Google Scholar]
  22. Weil GJ, Curtis KC, Fakoli L, Fischer K, Gankpala L, Lammie PJ, Majewski AC, Pelletreau S, Won KY, Bolay FK, Fischer PU, , 2013. Laboratory and field evaluation of a new rapid test for detecting Wuchereria bancrofti antigen in human blood. Am J Trop Med Hyg 89: 1115.[Crossref] [Google Scholar]

Data & Media loading...

Supplementary PDF

  • Received : 03 Jul 2016
  • Accepted : 25 Aug 2016
  • Published online : 07 Dec 2016

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error