Lymphatic filariasis--a parasitic infection commonly known as elephantiasis--is among the 10 neglected tropical diseases that the World Health Organization (WHO) is aiming to eliminate by 2020. In Cameroon, large-scale annual mass drug administration efforts are successfully curbing rates of LF, researchers now report in PLOS Neglected Tropical Diseases.
In 2000, more than 120 million people were infected with LF, and 40 million were disfigured and incapacitated by the disease. The WHO has proposed a strategy to eliminate LF which includes mass drug administrations and disability prevention programs. In Cameroon, annual drug administrations of ivermectin and albendazole began in 2008.
In the new work, Joseph Kamgno, of the University of Yaoundé, Cameroon, and colleagues studied 5,292 children aged 5-8 from 97 communities in five health districts in Cameroon that achieved at least 65% drug coverage in six annual mass drug campaigns. The communities were assigned into three evaluation units based on WHO criteria. A blood sample from each child was tested for LF.
In the three evaluation units, 2, 8, and 11 cases of LF were detected, giving rates of 0.13%, 0.57%, and 0.45%. These rates were below WHO critical cut-off thresholds--which would be 18 cases in each evaluation unit--for stopping treatment.
"These results support the cessation of mass drug administration in these implementation units, but this decision needs further thinking," the researchers say. It is possible for disease transmission to continue even when prevalence is very low, they add. "Post-mass drug administration surveillance activities should be organized to evaluate whether recrudescence can occur."
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Citation: Nana-Djeunga HC, Tchouakui M, Njitchouang GR, Tchatchueng-Mbougua JB, Nwane P, Domche A, et al. (2017) First evidence of lymphatic filariasis transmission interruption in Cameroon: Progress towards elimination. PLoS Negl Trop Dis 11(6): e0005633. https:/
Funding: This study was funded by the United States Agency for International Development (USAID) ENVISION Project through Helen Keller International. ENVISION is a global project led by RTI International in partnership with CBM International, The Carter Center, Helen Keller International, IMA World Health, Light for the World, Sightsavers, and World Vision. ENVISION is funded by the US Agency for International Development project under cooperative agreement number AID-OAA-A-11- 00048. The period of performance for ENVISION is September 30, 2011 through September 29, 2019. The Center for Research on Filariasis and other Tropical Diseases (CRFilMT), the platform where biological tests were performed for this study, is funded by Mectizan Donation Program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.