Measuring Our Success
According to the World Health Organization, many neglected tropical diseases (NTD)—including the seven that are the focus of END in Africa’s efforts–can be successfully eliminated after six years of mass drug administration treatments in endemic regions. As the END in Africa countries get closer to disease elimination, they will begin to shift their efforts from mass drug administration to administering sentinel site assessments, transmission assessment surveys and impact assessments.
Reaching the Thresholds to Stop Treatments
END in Africa’s ultimate goal is to get to the point where NTD disease prevalence is so low that drug treatments are no longer necessary in its focus countries. Once districts reach minimum disease prevalence thresholds, which are set by the WHO for each NTD, countries are able to stop mass drug administration (MDA) for that disease in those districts. So, it makes sense to use the number of districts no longer administering treatments as a measure of the project’s impact.
Achievements as of March 2015
55%* of LF-endemic districts have been able to stop MDAs for LF in Burkina Faso, Ghana, Niger, Sierra Leone and Togo.
*118 out of 213 districts
81%** of trachoma-endemic districts have been able to stop MDAs for trachoma in Burkina Faso, Ghana, Niger, Sierra Leone and Togo.
**81 out of 100 districts
Even as early as the end of FY2012, several END in Africa countries reported meeting the criteria to stop MDA:
- In Burkina Faso, 16 health districts (HD) have met the criteria to stop MDA treatments for LF, out of 63 HD that were initially endemic. In the case of trachoma, 18 out of 30 originally endemic districts have stopped treatments.
- In Ghana, 4 health districts have stopped MDA for LF, and 29 districts that had stopped treatment for trachoma continue to report prevalence rates below 5%.
- In Togo, post endemic surveillance shows that prevalence of LF remains below 1% in the country’s 7 previously endemic districts.
Assessing the Treatment Impact
In the first half of FY 2015, the following disease surveillance activities (DSA) were conducted through END in Africa:
- Pre-Transmission Assessment Surveys (Pre-TAS) were conducted in 17 HDs: 15 in Ghana and 2 in Niger.
- Post-MDA Transmission Assessment Surveys (TAS) for stopping MDA were conducted in 22 HDs: 9 in Burkina Faso, 7 in Ghana and 6 in Niger.
- TAS2 (the second post-MDA TAS for LF) was conducted to confirm the interruption of LF transmission in 13 previously endemic HDs: 5 in Ghana and 8 in Togo.
- District-level trachoma impact surveys were conducted in 7 HDs in Niger.
- Integrated schisto-STH evaluations were done in Niger (2 HDs) and Togo (35 HDs).
- Entomological evaluations for onchocerciasis were conducted in 8 HDs in Ghana; and epidemiological evaluations were conducted in 30 HDs in Ghana and 3 HDs in Niger.
Assessments conducted in Q1-2, FY2015, by country, type of assessment and disease*
|Burkina Faso||0||9*||0||0||0||0||2||Epi: 0
|Sierra Leone||0||0||0||0||NA||0||0||Epi: 0
NA: not applicable because the disease is no longer a public health concern; Epi: Epidemiological; Ento: Entomological; Pre-TAS: Pre-transmission assessment survey; TAS: Transmission assessment survey; TAS1: TAS conducted several years MDA has been stopped; TAS2: TAS conducted five years after MDA has been stopped.
* Burkina Faso: TAS1 was delayed due to the late arrival of ICT cards. All 9 HDs passed.
** Niger: TAS1 was conducted in 5 Evaluation Units (EUs) for 6 HDs; 4 EUs out of 5 passed the TAS. 5 HDs will stop MDA in 2016.
*** Niger: An impact assessment survey was conducted in 7 HDs and 6 out of 7 HDs have <5% trachoma prevalence and will stop MDA in 2016.
**** Ghana: Epidemiological evaluations were conducted in 56 sentinel sites in 30 HDs.
Assessments conducted in Q3-4, FY2013, by country, type of assessment and disease*
|Sentinel Site (a)/Pre-TAS||Transmission Assessment Survey||District level Impact assessment||Sentinel site assessment|
|Country||Number of Districts Assessed||Number of Districts Prevalence below 1%||Number of Districts Assessed||Number of Districts Prevalence below 1%||Number of Districts Assessed||Number of Districts Prevalence below 10%||Number of Districts Assessed||Median Prevalence Baseline (%)||Actual Median Prevalence (%)|
|Burkina Faso||10||Pending||9||6 (3 pending)||4 (+6 sub-district)||4(+6 sub-districts)||22||Pending||Pending|
|Niger||9||7||0||0||2 (+1 sub-district)||Pending (+1 sub-district)||8||Pending||Pending|
NA: not applicable because the disease is no longer a public health concern.
*Onchocerciasis (oncho) and Soil Transmitted Helminths (STH) not included. All five countries are currently providing oncho treatments and have not yet begun doing assessments. In some countries, STH is specifically treated, while in others, STH treatment piggybacks with LF or SCH treatment, since the same drugs are used; however currently, STH assessments are not conducted systematically in the five countries.
** Post MDA surveillance planned for FY2015. Residents in the assessed districts have completed the WHO-recommended drug treatment protocol and are not currently receiving treatments.
Coming Attraction: Disease Assessment Plans for FY2014
NTD control programs for the 5 diseases addressed by the END in Africa project are alike in that they have a common trajectory. They begin with disease assessment and mapping to determine the endemic districts that require treatment for local residents. After mapping, residents receive preventive chemotherapy, which is often given to entire communities through mass drug administration (MDA) exercises for a prescribed number of years, depending on the disease. Sometimes, surveillance is done during the MDA period; but more often, surveys and impact assessments are done after the treatments have been completed.
In other words, scaling down MDA treatments and expanding assessments is a sign of progress for END in Africa and national NTD programs; and considering the number of assessments planned, we expect FY2014 will continue to see plenty of progress toward our mission to reduce the prevalence of NTDs in the five countries that END in Africa supports.
Expected END in Africa-Supported Assessments for FY2014:
- Lymphatic filariasis: 17 districts in 5 countries will undertake pre-Transmission Assessment Surveys (Pre-TAS) and 82 districts will undergo TAS (with 9 districts in Niger beginning the initial post-MDA surveillance phase). Districts that have not yet completed MDA treatments will continue surveillance in sentinel sites.
- Schistosomiasis: 4 districts.
- Trachoma: 11 districts and 1 community.
- Soil-transmitted helminthes (STH): 4 districts.
- Onchocerciasis: 5 districts.
Disease assessment plans for FY2014, by country, type of assessment and diseasea
|Lymphatic Filariaisis||Trachoma||Schistosomiasis*||Soil Transmitted Helminths||Onchocerciasis|
(# HDs where MDA stopped)
Number of Districts with Assessment Plans
Number of Districts with Assessment Plans
|District level impact assessments||Sentinel site assessment||Sentinel site assessment||Epidemiological assessment|
(LF – 16; Trachoma – 21)
(LF – 4; Trachoma – 29)
(Trachoma – 15)
(LF – 8)
NA: not applicable.
* Survey to align with WHO completed FY2013
** 9 out of the 16 will begin the initial post-MDA surveillance phase
*** Community level assessment
**** Pending Pre-TAS results
***** Districts never treated, but Niger has requested evidence for its application for certification
****** To re-align treatment strategy with WHO guidelines
******* Hope Educational Foundation is conducting mapping of STH in a number of schools in Lome.
A survey is a survey is a survey?
How countries measure progress towards disease elimination: An overview of disease transmission surveys and assessments
Deciding when to stop MDA interventions in a community, region or district can be tricky. Stop MDA too soon and NTDs can regain their foothold and re-infect populations that were thought to be disease-free. Keep MDA going too long and valuable time, energy and resources are wasted.
To complicate matters further, transmission assessment is done a little differently for each NTD. So, it’s not surprising that NTD country programs and their partners, including END in Africa, put substantial time and effort into monitoring and evaluating the impact of their MDA interventions.
The various disease transmission instruments used to evaluate the impact of MDA interventions for each NTD addressed by END in Africa are summarized below.
A transmission assessment survey measures whether each countries’ pre-determined evaluation units (i.e. districts) have lowered the prevalence of infection to a level where disease recurrence is unlikely, even after MDA interventions have stopped. In the case of lymphatic filariasis (LF), current WHO guidelines recommend that countries conduct a formal Transmission Assessment Survey (TAS) to determine whether MDA can be stopped in an area that has had at least five rounds of annual MDA.
Prior to doing a formal TAS, END in Africa countries typically monitor the effectiveness of MDA interventions through so-called “Pre-TAS” surveys, including spot checks and sentinel site surveys. Both sentinel site surveys and spot checks collect data on parasitological data to measure disease prevalence in pre-determined geographical areas. However, the geographical locations of sentinel sites do not change over the course of the program, while spot checks may be done at different locations each time. In the case of LF, districts with parasite prevalence below 1% of the group surveyed are considered “non-endemic.”
The WHO has produced a table outlining disease-specific guidelines for the neglected tropical diseases addressed by END in Africa.
Number of people no longer at high risk for LF*
*FY 2016 data
Number of people no longer at high risk for blinding trachoma*
*FY 2016 data
Photo Credit: FHI 360
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