CONTAINMENT

contain + eliminate = no parasite

The Battle to Contain Resistance

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CONTAINMENT recently spoke to Dr. Robert Newman, Director of WHO’s Global Malaria Program, who was on a field visit to Pailin in Western Cambodia.

Dr. Robert Newman, director of WHO's Global Malaria Program. Pix by WHO/Sonny Krishnan

 

There is a long history in malaria control efforts. What’s different now and how has the landscape changed?

Obviously the big issue here right now is the emergence of resistance to artemisinins and this is not just an issue along the Cambodian – Thailand border, but is also a global issue. We rely very heavily on artemisinin-based combination therapies or ACTs and artemisinin is the key ingredient in that combination.

And the stakes are very high because right now we do not have other drugs in the development pipeline that are likely to reach markets before five years, the earliest. And that is an optimistic projection.

So it is really critical that we bring all forces together to try and preserve the efficacy of these valuable medicines.

Here in Western Cambodia we have an extraordinary effort made by the Cambodian National Malaria Control Program and their counterpart program in Thailand to contain the spread of these resistant parasites. The efforts here, I think, have been groundbreaking in their comprehensiveness. Some of the approaches that have been taken are also novel and pioneering.

The Cambodian government has banned the sale of monotherapies. Do you think there should be a similar ban regionally within the Association of Southeast Asian Nations or ASEAN?

Absolutely. I think we all agree now at this point that the use of oral artemisinin monotherapies is probably the single greatest factor for the spread of artemisinin-resistant parasites. In 2007 there was a World Health Assembly resolution that called for a halt in the marketing and use of these compounds.

The worst case would be the spread of the delay in clearance of the [plasmodium] parasites. Right now we are finding an increase in the percentage of patients who are still positive on Day 3. That will be the hallmark of this problem [of resistance]…

While there has been some forward movement in the number of countries that have complied both in terms of shutting down the manufacturer, marketing of these drugs and to some extent in their use, we still have to go some way. This is such an urgent issue. The time to do that is now.

We need all countries, globally – particularly here in the Greater Mekong sub-region and ASEAN to ensure that these dangerous medicines are removed immediately from the market place.

What are the differences between containment and elimination; elimination and eradication?

Containment would mean in this context that we take these resistant parasites and don’t let them spread outside the area where they have been identified. So at this point the confirmed areas are along the Thai-Cambodian border, although there are other areas in the Greater Mekong sub-region where we have suspicion of their emergence.

Elimination would mean that we would actually be able to eliminate all of the parasites. That is a very difficult thing to document. Obviously, if we are able to eliminate these resistant parasites then the risk of their spread is essentially gone.

The term elimination is more generally used to refer to the reduction at the country level of local transmission of malaria to zero. So usually we talk of eliminating malaria at a country level.

Eradication is reserved for the global incidence of malaria going to down to zero. And that’s for all plasmodium species and not just for falciparum. That obviously remains the ultimate public health goal, although I believe that will take 40 or more years to achieve. It would require the development of new transformative tools that we do not have, yet.

What’s the worst case scenario for MDR-falciparum malaria?

The worst case would be the spread of the delay in clearance of the [plasmodium] parasites. Right now we are finding an increase in the percentage of patients who are still positive on Day 3. That will be the hallmark of this problem [of resistance].

If that were to continue to worsen, artemisinins would become less and less efficacious. It would then take longer and longer for patients to clear [plasmodium parasites in their blood], and we could get to the point of truly having failures to ACTs.

Right now we have resistance to artemisinins, but artemisinin-based combination therapies (ACTs) still remain efficacious. That is a very important message.

But if that situation worsens, if were to lose ACTs, and if it spreads to the shores of Africa, we could have a public health catastrophe.

As you know we still have more than 700,000 estimated deaths a year in Africa from malaria. We rely entirely on ACTs for the treatment of falciparum malaria. If we were to lose those medicines in Africa, that would be a catastrophe. This is precisely what the extraordinary efforts in the Containment Project, here, in the Greater Mekong sub-region are trying to prevent.

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  1. […] a recent interview with CONTAINMENT, in Pailin in western Cambodia, Dr. Robert Newman, WHO’s Global Malaria Program director, warns of a worse case […]


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