Post-MDA surveillance ( including xeno-monitoring) Krishnamoorthy K. Vector Control Research Centre Pondicherry India

Table 2. Number of districts covered under MDA in relation to drugs No. roundsDEC alone DEC + albendazoleTotal State to review the results of Mf survey in the MDA districts every year and the districts recording less than 1% Mf prevalence in all the sentinel and spot-check sites should complete Mf survey in 10 additional sites so as to generate information before next round of MDA. MDA need not be conducted in districts recording less than 1% in all the 10 additional sites. Resources for one round of MDA can be saved.

The coverage is reported as number out of eligible population (drug coverage). Due to wide variation in the proportion of eligible population, the coverage becomes inflated. Therefore, it will be useful if the coverage is calculated out of total population. Directorate to make necessary changes in the reporting formats. Independent assessment of coverage and compliance is not carried out in many districts. This information is required to identify the gap and identify methods to bridge it. Programme governance is observed to be weak in some states. There is no feedback from the reviews at higher levels and action plans suffer. Inadequate supply of drugs was common even during last round at all level. This results in low levels of coverages. Along with activity reports, action taken reports also should be reviewed at the Directorate of NVBDCP. Drug compliance was observed to be below the threshold level in some district, warranting strong social mobilization activities.

Country Populatio n (M) Population requiring PC for LF (M) Endemi c IUs Numbe r of IUs require MDA Numbe r of IUs stoppe d MDA Numbe r of IUs require d MDA in 2012 Numbe r of IUs covere d Geograph ical coverage Total population of Ius covered (M) Reported number of people treated (M) Program me (drug) coverage Nationa l coverag e Number of IUs subjected to TAS Banglades h % %*18.7%5 India % %46.5%0 Indonesia % %19.1%24 Maldives Post MDA surveillance1 Myanmar % %0.0%5 Nepal % %29.2%0 Sri Lanka Post MDA surveillance8 Thailand Post MDA surveillance357 Timor- Leste % %0.0%0 Total % %37.5%400 Table 1. Details of MDA carried out in SEA Region during 2012

Mapping and remapping protocols Mapping protocolRe-mapping protocol Number of sites230 Selection of sitesProbable (risk)pps Target age15 yrs or older10 yrs Sample ToolMf/AgAg Cut-off1%2%

Development of an appropriate and feasible surveillance strategy to monitor the post-MDA epidemiological situation is necessary to: a)declare the areas/intervention units are free from LF transmission or b)take steps to prevent resurgence of infection, if any. Antigenaemia prevalence has been recommended to monitor post MDA situation. However, the change in this parameter during the post MDA period (five years) is not known to understand the usefulness of this indicator and also to decide on the frequency of post MDA survey. Rationale

Study area VillagesPopulation Mf prevalence Pre MDA Post 3 rounds Post 6 rounds % reduction (pre-post 6) Kallakulathur Keelidayalam Sendiampakkam Sitheni Total Intervention = Mass annual single dose DEC + albendazole Six rounds – supervised administration ( ) Coverage = above 70% Post 6 rounds of MDA = <1% mf Ag prevalence (3-6 years) = 0/93 Stopped MDA in 2008

Objectives To understand the post-MDA changes in antigenaemia prevalence in children (6-10 years) To relate the post-MDA changes in antigenaemia prevalence in children with the antigenaemia prevalence in adult groups (16-45 years) To evaluate the value of xenomonitoring as a tool for post- MDA surveillance To determine the required duration of post-MDA surveillance period

Evaluation Unit Evaluation Unit - four villages VillageHouseholdsFemaleMaleTotal Kallakulathur Keelidayalam Sendiampakkam Sitheni Grand Total

Overall 7.76 % n=580 Overall 0.05% n=585

Indicators and tools 1.Antigenemia (mass) survey in : Diagnostic tool – ICT Target age class o 6-10 years (children) o years (adults) 2.Entomological survey: 5000 vector mosquitoes Gravid traps Dissection to assess the vector infection These surveys were repeated after two years. The first survey was done in 2011 and the second in 2013

2013 Villages 6-10 years16-45 yearsTotal Sample Ag +ve%Sample Ag +ve%Sample Ag +ve% Kallakulathur Keelidayalam Sendiampakkam Sitheni Total Villages 6-10 years16-45 yearsTotal Sample Ag +ve%Sample Ag +ve%Sample Ag +ve% Kallakulathur Keelidayalam Sendiampakkam Sitheni Total

Year 6-10 years PopulationSample Coverage (%) PopulationSampleCoverage (%) 2011 (post MDA 3) (Post MDA 5) Coverage for ICT survey

Ag prevalence during post MDA

TAS exercise (6-7 years) YearPopulationSampleCoverage (%) Ag +ve

Ag survey Longitudinal (cohort) folllow-up Total = 1053 Positive in 2011 = 23 Loss in 2013= 19 (82.6%) Negative in 2011 = 1030 Gain in 2013= 15 (1.46%)

Entomological survey – (2011) VillageTraps Vector (C.q) Trap density InfectionIntensityInfectivity CollectedDissectedPositive Kalla Kulathur Sithani Keezh Edayalam Sendiampakkam Total

Entomological survey – (2013) VillagePopulatio n No. collections No. traps No. collecte d Density range per trap Per trap density No. dissecte d No. infected No. infective Sithani Keelidayalam Kallakulathur Sendiampakkam Total Period of survey3 months

Absence of recent transmission in two consecutive post-MDA surveys indicate that 1% Mf prevalence was safe to discontinue MDA. Prevalence of antigenemia prevalence among children (6-10 years) is less than 1% during post MDA period. Post-MDA Ag-prevalence between children and adult age class is not related, and therefore adult age class cannot be targeted for evaluation. There was reduction in antigenemia prevalence in both children (28%) and adult age classes (33%). The relative change in Ag prevalence between the age classes was also not significant. Loss of infection was about 83%. Xenomonitoring after two years of stopping MDA did not show evidence for vector infection implying absence of potential mf carriers in the study community. Conclusion

Achieving the sample size (census) Migrant children Assessing school enrolment rates “hotspots” Challenges in implementing TAS