LFTAS + Biplex + DBS in Oncho endemic areas in Cameroon

To assess if transmission assessment surveys (TAS) for lymphatic filariasis (LF) are a feasible platform to integrate transmission assessment for onchocerciasis, using the same age group (6-7 years old) and the same prevalence threshold (<2%) that the LF programs utilize.

1. To perform the TAS for stopping LF MDA and use it as platform for Oncho impact assessment.
2. To assess the level of endemicity of Oncho following at least five rounds of MDA in hypo, meso and hyper endemic districts.
3. To study the performance of the Wb123/Ov16 Biplex rapid diagnostic test (RDT) to assess Oncho and LF transmission interruption.


Preliminary study findings:

  • This study involved an integrated impact assessment of onchocerciasis and lymphatic filariasis using the LF TAS platform and the serologic rapid text Biplex in the Northern area of Cameroon.
  • The study sites covered 31 health districts in the Far-North and North regions, constituting nine evaluation units, for which TAS1 was planned.
  • Community-based cluster surveys were conducted collecting GPS and demographic information, lymphedema symptoms, and testing by FTS, by Wb123/Ov16 Biplex, and by Night Blood Smear of 6 and 7 year old children.
  • In total, 13,957 children were recruited from 267 enumeration units (villages).
  • Ten children showed evidence of LF exposure or infection: 4 were positive by FTS and 6 were positive by Wb123 (via biplex).  No children tested positive for both FTS and Wb123. 
  • Night blood smears - conducted in children who were positive by FTS and by Wb123/Ov16 Biplex - were all negative.
  • For onchocerciasis, one individual was Ov16 positive (by Biplex).

In conclusion, all nine evaluation units passed the TAS1 assessment. As for onchocerciasis, study results are consistent with the previous hypo-endemic status of the area.

Countries: Cameroon