EVALUATION OF ENVIRONMENTAL POLIOMYELITIS SURVEILLANCE SYSTEM IN LAGOS STATE, SOUTHWESTERN NIGERIA, SEPTEMBER 2013
Nigeria is one of three countries still endemic for polio globally and is a signatory to the WHA resolution in 1988, to eradicate polio. WHO recommends complementing Acute Flaccid Paralysis surveillance with environmental surveillance (ES) for polio virus. Lagos State commenced ES for polio in 2012. We conducted an evaluation of the Lagos State system for ES for polio.
METHODS:
We interviewed six key informants at national, state and Local (LGA) level. We reviewed Lagos State ES data from 2012 to September 2013. We used content analyses for qualitative data to assess the key surveillance attributes (CDC guidelines).
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RESULTS:
Samples are collected from designated sewage sites by trained environmental Health officers every 2 weeks and reach the lab within 3 days of collection.ES system is based on and uses resources the AFP system, it can be used to detect other enteroviruses as currently it must isolate at least 10% non polio enteroviruses (NPENT), completeness is 100% and data is adequately managed and readily available. Surveillance data flows from LGA through the WHO accredited regional laboratory (where confirmation is done) to national level. Results are out within 10 days of sample collection. Partner agencies provide 100% of system’s operating resources. Lagos State detected one environmental wild polio virus type 3 (WPV3) in July and another in November 2012 (total two cases). No environmental polio viruses have so far been detected in 2013. Detection of environmental wild polio virus triggers vaccination of children less than 5 years old in the State.
CONCLUSIONS:
The system is simple, flexible, complete (100%), acceptable, stable and useful, quite sensitive though representativeness is difficult as results are not readily generalizable. Environmental polio surveillance is a useful complement of AFP surveillance in the efforts to eradicate polio. There is a need to expand the geographical coverage of the environmental polio surveillance system.