Eradication &Surveillance Bill Brieger | 23 Nov 2009 05:05 pm
Lessons from guinea worm eradication
When the international effort to eradicate guinea worm started in 1987 the focus was on only 20 currently endemic countries. Tayeh and Cairncross report the status of these countries at the end of 2008 –
- 6 have interrupted transmission and been certified as free of guinea worm
- 8 have interrupted transmission and certification is under way
- 6 are still reporting cases, of which three are a major focus
Guinea worm is a highly focal disease that does not move too easily. The differences in transmission and the sheer number of endemic countries sets malaria off clearly from guinea worm. But are there lessons to learn?
Of concern here is the process of certification that transmission has stopped. Looking at malaria’s pathway to elimination, we realize that most countries are in the scale-up phase of control and have a long way to go to sustain control and enter pre-elimination, let alone elimination and then prevention of re-introduction. At some point in the elimination phase, which could be 20 years from now, countries will need to be certified free of malaria.
Tayeh and Cairncross address the realities that larger scale eradication programs like polio take a regional approach to certification, as a country-by-country approach would be too costly. They also discuss the dangers of re-introducing a disease to places that are free of transmission, which corresponds well with the final phase of the malaria elimination pathway.
Another issue is the challenge of identifying cases when transmission becomes very low. The system of rewards to citizens may not be most appropriate for malaria, but the ability to keep people engaged in eradication efforts when they don’t see a reason will be difficult.
What our colleagues don’t mention is the challenge of false positives. We found that local beliefs in guinea worm endemic areas can lead to high false positive rates on surveys – that swelling on his leg, that ache in her stomach, those rashes on his body. Local beliefs about malaria presentation abound, too. It is good, therefore, to start considering what surveillance and certification of malaria elimination will look like now, so a good system is in place when the time comes. In fact we may get good opportunities to practice in places like Zanzibar.