Lymphatic Filariasis Positive-Case Follow-up After TAS 2 in Haiti

Because the cut-off for passing a transmission assessment survey (TAS) is a critical cut-off based on the upper 95% confidence interval of less than 1 or 2% (dependent on primary vector) prevalence of antigenemia among children ages 6 and 7, many implementation units pass TAS with one or more positive FTS results. However, the presence of any FTS positive children in a TAS 2 or TAS 3 indicates possible ongoing transmission. The WHO LF program manager’s manual encourages program managers to conduct follow-up surveys in communities where antigen positive children are found. However, there is currently no published guidance on how this follow-up should be conducted. The goals of this project were to determine the implications of one or more positive FTS results and to provide evidence towards recommendations on how to follow up on these results. In Nippes, Haiti, 8 positive children were identified during TAS 2. Of these, 4 were in the urban area Miragoane. Follow-up occurred in the villages of each of these children in August 2019. Additional FTS positive results were identified in Miragoane and in the communes of residence of 2 of the other 4 index case children. The majority of FTS positive results were in Miragoane. In response, the program has decided to evaluate Miragoane separately from the rest of Nippes for TAS 3.