Surveillance-response approaches for malaria control and elimination

MARCEL TANNER: My name is Marcel Tanner. I’m from the Swiss Tropical and Public Health institute in Basel, Switzerland, and I’m also Professor of Epidemiology, Medical Parasitology, and Public Health at the University of Basel, as well as President of the Swiss Academy of Sciences. Today we would like to talk a little bit about how we reach elimination of malaria by looking on what information we have to collect and how we have to use this information swiftly in order to cut transmission, means eliminate malaria in the different parts of the world. Therefore, our learning objectives are to start with how we are monitoring and evaluate our malaria control and elimination programs, but how we also do, more specifically, out of this classic remedy malaria surveillance. We would like to explain a little bit on the different strategies of malaria monitoring and evaluation and how we reach out of these concepts really to surveillance-response approaches. And we then understand how the surveillance-response approaches are not only theoretically propagated, but really put into a specific endemic setting in order to serve our programs of malaria elimination. And how, at the end, these parts of surveillance and response are part of the overall public health response in our malaria elimination and, finally, eradication programs. We will have the strategies for surveillance-elimination in different settings that we look at, and then we have an in-depth look on the data collection and on how we make decisions out of this data that we collect, and how we actually move from collecting data, monitoring and evaluation, to it’s surveillance-responsive approaches. As well as we will look at specific case studies that have used this approach successfully to reach malaria elimination. And of course, the final aim is to understand that with these surveillance-response approaches, we not only achieve elimination, but also we really tackle the problem when it is worse and where we actually look for the best equitable approaches in reaching elimination. The first part will be really to look at strategies for surveillance systems in different elimination settings. The basis of this is that we have in our population in any malaria endemic area three types of populations. We have the not infected asymptomatic people. We have the infected asymptomatic people. And we have infected symptomatic people. And for each of the three population groups we have to do the same thing. We have actually to see that the not infected asymptomatics do not get infected. We have to see that the infected asymptomatic cannot continue to transmit. So that means we treat them so that the reservoir of the infection is eliminated. And we have the infected symptomatic people, where the goal is that, first of all, they are not getting sick or if they are sick they actually are cured, and we also prevent that they further transmit to the mosquitoes. And if we do this to all the three population groups, then we can achieve the interruption of transmission. And that’s the aim. Elimination means interruption of transmission. It does not just mean reducing of morbidity. And in order to reach eradication, you must actually bring three building blocks together. First of all, you have to detect all the people who have parasites– the reservoir. Secondly, you have to cure the people, so you have to eliminate the reservoir. And of course, you have to prevent that any parasites are taken up by the mosquitoes. And it’s only if the three building blocks are put together that we can achieve elimination and eradication. The key issue on this whole thing is that it occurs concurrently. You cannot do a little bit of detection, a little bit of cure, and a little bit of prevention of transmission. You must do these three things together in a given endemic area– in a given transmission pocket. Surveillance is key in order to detect the parasite. Surveillance is key in order to detect people who carry the parasites or could transmit malaria. And here is a graph from the malaria report of 2015 already. And it said actually that surveillance systems are unfortunately weakest where the highest burden is there. And we just take this as a reminder to say that where surveillance is not functioning, our control and elimination efforts are not functioning. That’s the take-home message. And after having not just published this information, WHO has published a new version of the surveillance manual. The surveillance manual is not just a book with recipes. It just emphasizes how important it is to really detect parasites, to understand what a transmission pocket is, in order to really act, as we said, simultaneously on asymptomatic and symptomatic people in order to cut transmission. This has been launched in 2012, and unfortunately, we must say today this message of having rigorous surveillance and having followed it by an adequate public health response is still not translated into action in many, many places.

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