Abstract

BackgroundTogo is a country previously endemic for lymphatic filariasis (LF). In 2010, following nine years of mass drug administration (MDA) for LF, the country established a post-treatment surveillance (PTS) system. We present here the results of these PTS activities, carried out from 2010 to 2015, as well as the findings of follow-up investigations in 2016 to confirm the absence of infection in previously infected individuals.MethodsThe routine surveillance established in 2010 consisted of a network of 47 laboratories, which searched for Wuchereria bancrofti microfilaria on nocturnal blood smears collected for malaria diagnosis and an additional network of 20 peripheral health facilities, which collected dried blood spots and tested them for Og4C3 antigen. Two transmission assessment surveys (TAS) were also undertaken, as recommended by WHO, in 2012 and 2015. Any positive case identified through any surveillance activity was immediately retested by nocturnal smear and confirmed cases were immediately investigated by screening family members and neighboring household members. In 2016, 32 of the 40 positive cases detected during TAS or laboratory and health facility network activities were traced and whether confirmed positive by nocturnal smear or not were tested again simultaneously by filariasis test strip (FTS), Og4C3 and a nocturnal blood smear to rule out any active infection.ResultsFrom 2010 to 2015, the laboratory network identified one microfilaria-positive individual (0.0% of 26,584 persons tested) and the peripheral health facility network detected 19 Og4C3-positive individuals (0.28% of 6788 persons tested). All 19 Og4C3 cases were negative for microfilaremia by nocturnal blood smear. In the 2012 and 2015 TAS, thirteen and six ICT/FTS positive cases, respectively, were identified, which were significantly below the critical cut-off (18–20 cases) across all evaluation units. Three of the six ICT/FTS-positive cases from the 2015 TAS were positive by nocturnal smear; immediate investigation identified one additional microfilaria-positive individual. Epidemiological investigation revealed that four of the five cases of microfilaremia were imported from another country in the region. In 2016, 32 of the 40 positive cases detected by at least one test during all surveillance activities were traced: four (12.5%) individuals were still positive by FTS but all 32 individuals were negative for microfilaremia and Og4C3 antigen.ConclusionThe results of post-treatment surveillance in Togo have demonstrated that W. bancrofti filariasis is no longer of public health concern in Togo, more than six years after stopping MDA. Every possible effort should be made to maintain surveillance in order to promptly detect any resurgence and preserve this achievement.

Highlights

  • Togo is a country previously endemic for lymphatic filariasis (LF)

  • Microfilaremia and Og4C3 identification resulted in 1 (0.003%) and 19 (0.28%) positive cases respectively (Table 1)

  • In addition to the two post-mass drug administration (MDA) surveys recommended by the World Health Organization (WHO) in LF-endemic districts, Togo conducted six years of supplementary surveillance that covered the entire country, including both endemic and nonendemic districts

Read more

Summary

Introduction

Togo is a country previously endemic for lymphatic filariasis (LF). In 2010, following nine years of mass drug administration (MDA) for LF, the country established a post-treatment surveillance (PTS) system. Lymphatic filariasis (LF) is a severely debilitating, disfiguring and stigmatizing mosquito-borne disease caused by infection with the nematode species Wuchereria bancrofti, Brugia malayi or Brugia timori. The elimination strategy has two components: (i) transmission interruption through drug administration to every eligible person in endemic areas; and (ii) morbidity management and prevention of disability by providing access to basic care for LF-related diseases to every affected person in endemic areas [5, 6]. After nine years of mass drug administration (MDA) with satisfactory outcomes per the WHO guidelines and based on evidence from a transmission assessment survey (TAS) of the probable interruption of transmission, Togo stopped mass treatment for LF in 2009 and initiated post-treatment surveillance (PTS) activities in 2010 [8]

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call