Four years ago, in 2009, I wrote an article for a Dutch newspaper (Bionieuws) with the title 'It is not yet time for a party on Zanzibar'. My article was a response to Tachi Yamada's blog on CNN 'Where have all the malaria patients gone?'. Yamada at that time was touring the spice island together with Ray Chambers and Margret Chan, and for sure their trip must have been pleasant and satisfying. After all, the renewed impetus (largely through the US Presidential Malaria Initiative) in malaria control was starting to pay off. Indoor residual spraying and massive distribution of LLINs yielded a spectacular decline in malaria prevalence. Yamada ends his commentary with a pretty strong statement...
He writes: 'Where have all the patients gone? Home, where they can live happier, healthier lives. Let them be the retort to the skeptics of development assistance'. Now, that was four years ago. Yamada has since moved on and is no longer the President of the Global Health Programme at the Bill & Melinda Gates Foundation. But his words are forever online and can be traced. In my newspaper article of 2009, in response to Yamada's commentary, I expressed my concern that Zanzibar's impressive results should not lead to euphoria since it was not much more than a repetition of the elimination activities that took place in the 1950s and early 1960s. Which ultimately collapsed and brought prevalence levels back to the pre-campaign level.
When I teach these days, I use Zanzibar as the perfect example of what I coined 'the trampoline effect'. That efforts to control can reap fruits within a short period but that inevitably the gains are lost when either funding dwindles or evolution catches up with us and resistance favours the revenge of our enemies: Anopheles and Plasmodium.
And this week, in an article published in Parasites and Vectors, we see exactly that happening. Khamis Haji and colleagues have measured what we all could have seen coming at us: That resistance to pyrethroids on Zanzibar is now full blown. Is this a surprise?: No. Could this have been foreseen?: Yes. Was it predicted?: Yes. Besides this, Haji et al. also show that the LLINs are not performing the way they should and lose effectiveness already after 6 washes. Now, let's then put Yamada's words and Haji et al.'s conclusion together here:
Yamada (CNN Commentary, 2009): 'Zanzibar -- a relatively small but striking example -- has virtually eliminated the disease over the past five years. These successes show what a combination of political will, technical resources, and financial commitment can do when applied to a strategy that works.'
Haji et al. (P&V, 2013): 'The sustainability of the gains achieved in malaria control in Zanzibar is seriously threatened by the resistance of malaria vectors to pyrethroids and the short-lived efficacy of LLINs. This study has revealed that even in relatively well-resourced and logistically manageable places like Zanzibar, malaria elimination is going to be difficult to achieve with the current control measures.'
There are some important lessons to be learned from this:
1) Bringing malaria down to really low levels can be done with the tools at hand and within a few years. Zanzibar is a good example but there are many other examples of where this has been demonstrated;
2) If you then (when prevalence is really low) stop efforts to eliminate but want to sustain the gains you will lose the fight. Since reliance on biocides (drugs and insecticides) is the sure recipe for evolution to outwin us;
3) If you then resort to using other biocides (Haji et al. tested DDT and bendiocarb) than you will be in the game for a few more years until resistance to these new chemicals takes over;
4) Keeping malaria at a very low level is difficult, hard, costly, and maybe even impossible.
So then, should we do nothing? Of course not. And, one could argue, it is easy for me (here in the Netherlands) to write about failure...what did I do to contribute to malaria control/elimination on Zanzibar?
Well, below the list of activities I undertook regarding Zanzibar:
1) In 2010 I wrote an article on Zanzibar that is essentially the same as what you read here (you can read it here). In it, I show the video below:
2) In 2010 I visited Zanzibar and talked to the permanent secretary of health, Dr. Jiddawi, about my concerns. I made a case for area-wide larval source management as an add-on to the IRS/LLINs that were in place. As a means to further reduce, if not eliminate, the disease. Dr. Jiddawi was very much interested in this, and referred me to Admiral Ziemer, the man at the helm of US PMI. And so I contacted Admiral Ziemer. The result? The best I got was a response (email: 17 June 2010) from Charlene Voorhees, his assistant, who claimed:
Dear Dr. Knols