WHO lists the milestones towards validation of elimination as:
- Stop the spread of infection through mass drug administration
- Implement MDA in all endemic areas (100% geographical coverage)
- Reduce infection below a threshold at which transmission is not sustainable in all endemic areas and stop MDA
- Demonstrate sustained reduction of infection below the threshold no earlier than 4 years after stopping MDA
- Alleviate suffering by managing morbidity and preventing disability (MMDP)
- Define burden of disease (estimates of the number of patients)
- Recommended minimum package of care available in all areas of known patients (100% geographical coverage)
The latest WHO Weekly Epidemiological Report (WER) published in 2017 noted the progress towards the Validation of LF elimination as a public health problem. Elimination of LF as a public health problem means reducing infection prevalence in an area to below target thresholds and providing the recommended basic pack- age of care in all areas with lymphoedema or hydrocele patients. A process of validation is used for formal confirmation of elimination as a public health problem. As a sign of continuing global progress against LF, WHO acknowledged that the evidence documented in dossiers received from Egypt and Thailand in 2017 met the validation criteria
51 countries categorized in the first 3 columns of the WER Table 1 were considered to require MDA in 2017. Five of these had not started MDA. Thirteen countries have implemented MDA but not in all endemic Implementation Unites (IUs). Until MDA reaches every endemic IU each year, these countries (columns 1 and 2) are not aligned towards achieving elimination targets. For the 33 countries that either in 2017 or previously reached all endemic IUs with at least one round (column 3), future MDA rounds must be implemented consecutively with effective coverage to enable those countries to stay on track for achieving elimination. Although MDA at 100% geographical coverage has been attained in previous years, Burkina Faso, Ghana, Mozambique, Haiti, India, American Samoa, Samoa and Tuvalu did not implement MDA in all IUs where warranted in 2017. MDA was no longer required in the 21 countries where surveillance is needed to ensure that infection levels remain below elimination thresholds, including those that have not achieved validation criteria (column 4) and those acknowledged as having achieved elimination as a public health problem (column 5).
Since 2000, a cumulative total of 7.1 billion treatments have been delivered to >890 million people at least once. In 2017, the proportion of the total population requiring MDA was 52.4%, with 465.4 million people treated in 37 reporting countries. MDA was not implemented in 9 countries where required. Reports from 5 countries are still awaited. Updates will be posted on the Global Health Observatory PC data portal.7 National programmes targeted 585.9 million people for treatment during MDA and achieved programme coverage of 79.4%. In 2017, an estimated 24 million preschool-aged children (2–4 years of age) and 133.1 million school-aged children (5–14 years of age) were treated during LF MDA.
The number of people requiring interventions for neglected tropical diseases (NTDs) has been defined as the NTD indicator to monitor progress towards achieving Sustainable Development Goal (SDG) 3.3. In GPELF, the total population in all IUs in a given country with evidence of LF endemicity is considered the population at risk and requiring MDA. Based on GPELF activities through 2017, 554 million persons no longer require MDA, a 38% reduction from the total population living in IUs that were considered endemic.
Morbidity management and disability prevention (MMDP) is the WHO-recommended strategy to alleviate suffering and prevent further progression of disease. The following basic package of care must be available for patients: surgery for hydrocele (in W. bancrofti-endemic areas), treatment for episodes of adenolymphangitis, management of lymphoedema to prevent episodes of adenolymphangitis and progression of disease (http://apps.who.int/iris/bitstream/10665/85347/1/9789241505291_eng.pdf ). The ultimate goal is 100% geographical coverage of the basic package of care available in all IUs with known patients.
In order to report on the progress of availability of MMDP services, countries should locate patients and enable the health system to provide care in those areas. The availability of care should then be monitored and may also be used as an indicator of equity in progress towards SDG 3.8, universal health coverage (UHC). Data reported to WHO concerning MMDP are summarized in Table 3. Limited MMDP data are available from 53 countries. Partial estimates of the numbers of lymphoedema patients were available from 8 additional countries in the African Region and of hydrocele patients from 12 additional countries. Compared to 2016 WER, the reports indicate that 18 additional countries are monitoring MMDP by IU.
See WHO Weekly Epidemiological Report for the full detailed report