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'It always seems impossible until it is done' – Nelson Mandela

February 5, 2014 - 20:51 -- MESA Alliance

'The science of malaria eradication' Keystone Symposia
Monday Feb 3rd

From bioethical considerations, to mapping trends in malaria transmission with basic biology. From inspiring lessons in other eradication campaigns, to regulatory issues around tools which benefit populations, to novel genetic technologies which modify mosquitoes and the parasite life cycle. The first day of the Keystone Symposium on the science of malaria eradication set the scene for sharing and debating new discoveries and innovative approaches to malaria eradication.

Following the opening remarks, Frank O. Richards (Carter Center, USA) recounted elimination and eradication campaigns of three neglected tropical diseases. ‘Start in the hardest places first; by definition they will be the ones that take longer’, he suggested. Adding that, the need for surveillance and community-based approaches cannot be underestimated, and that only initiatives that address the problem from a regional perspective have any chance in achieving their goals.

Dyann Wirth (Harvard School of Public Health, USA) emphasized the need to understand the selective pressure at a biological level. Barcoding of Single Nucleotide Polymorphisms (SNPs) from parasite isolates was discussed as a key technology to evaluate trends in parasite evolution, and to assess trends in transmission, as well as the impact of interventions.

Vector biology was also addressed, with consensus that malaria eradication will not be successful without targeting the mosquito. The presentations focused on genetic tools with the potential to replace mosquito populations or to render them incapable of transmitting the parasite. Some examples involved genetic ‘scissors’ and others used bacteria symbionts through paratransgenesis.

Presentations were followed by lively Q&A and discussions at the poster sessions. In such a multidisciplinary environment, the importance of integrating strategies was highlighted. As an example, one participant suggested that we could start by reducing mosquito populations through genetic approaches, and then bring in Mass Drug Administration to finalize the job.

A number of questions remain open, however. What drives the parasite selection process, and which parasites or genomes persist over time? Are all parasite strains equally transmitted? What is the correlation between gametocytes and transmission and what are the determinants of infectiousness? How can vector biology strategies be implemented to sustainably reduce malaria transmission?

The good news is that malaria elimination and long-term eradication is not perceived as unachievable. Nelson Mandela was quoted to reinforce this message: “It always seems impossible until it is done”.

This blog was written by MESA Secretariat, and posted simultaneously on MESA’s blog on MalariaWorld and ISGlobal’s blog.
 

Comments

Andre Siqueira's picture
Submitted by Andre Siqueira on

Great that you are sharing the meeting with us! Thanks a lot! Will the abstract book be available for the public?
Enjoy it there!

Andre M. Siqueira

Submitted by MESA Alliance on

Andre, hope this helps! http://goo.gl/hwO746 You can also write to Keystone Symposium for a printed copy at around 30 USD. Best, Kate

Andre Siqueira's picture
Submitted by Andre Siqueira on

Thanks a lot, Kate! It is a great resource!
All the best!

Andre M. Siqueira

William Jobin's picture
Submitted by William Jobin on

Greetings,

I congratulate the MESA folks in Yucatan who are focussing on ways to suppress malaria - although I am pretty sure we will not eradicate it within our lifetimes.

But I wonder about the advice reported from Frank O. Richards, to attack it in the hardest places first. While that might apply to smallpox, the only human disease ever eradicated, would it make sense for malaria? The two diseases have few similarities, neither in their epidemiology, their ecology, nor their pathogens.

If we follow Frank Richards' advice, we should focus our efforts to suppress malaria on Equatorial Africa first - undoubtedly the hardest place. That means Somalia, Southern Sudan, Central African Republic, the Congo and Gabon. If we followed his advice it would be a disaster.

Perhaps we should realize that smallpox was a simply transmitted contagious disease, while malaria is an ecologically embedded disease which transmits through many intricate links to human society. In a recent analytical study comparing the slave trade, colonialism and malaria for their importance in depressing economic development in Africa, it was concluded that malaria was most important.

Not to mention that the ultimate Vaccine was available against smallpox, yet there is no malaria vaccine on the horizon with any practical value in a public health campaign.

But maybe if all of you on the Yucatan put your incredible brain power to work, you can prove me wrong. Please try.

Bill Jobin
Still hoping and waiting

William Jobin Director of Blue Nile Associates

Submitted by Ricardo Ataide on

Hi Bill,

I have to admit that I was one of the people who, when faced with the question 'should we shrink the map, or go for hot-spots' replied without hesitation, hot-spots. I agree with you that saying lets go and actually achieving it are two very distinct entities, but I still believe that we have to try. All the stakeholders are tired of seeing endless efforts and resources being applied and with only small victories (in comparison) being achieved. I say, lets go to a hot-spot and hit it with everything we've got, the ripples will certainly extend to all the surrounding areas and the gains will be more pronounced. Will it be difficult? No doubt it will. Will it be worth it? Most definitely!

Ricardo Ataíde

William Jobin's picture
Submitted by William Jobin on

Hi Ricardo,

I think I understand your preference to start in the difficult spots, but I think it does not conform to what actually happened with the eradication of smallpox, the only human disease eradicated.

The smallpox eradication campaign ended in Somalia, it did not start there. It ended in the small, coastal village of Merka, down the coast from Mogadishu. I visited it about 1990 to see the historic place for myself, and got arrested. Some of our many problems in traveling around that country were the military checkpoints on the highways - which sometimes got violent. I couldn't go back because the civil war was soon spread to Mogadishu by the Warlords, and the only airport in the country was closed. Do you remember the Blackhawk Down incident? There is no electricity. How would you get refrigeration, or set up a lab by candle-light? Where would you find cold beer?

To attack smallpox they organized a blitzkrieg of vaccination there, in and out by helicopter. So they only had to be operating for a short time. But to attack malaria we have to organize long-term, comprehensive integrated programs that will continue for generations. How would you do that in the face of the violence and instability of Somalia? Or the Congo? or the Central African Republic? If you would go to Somalia today to start an attack on malaria, you would have to deal with mindless attacks by Al Shabaab. Do you really think that is a good idea?

My preference would be to start in the most stable and democratic places where we could maintain the fight, and gradually expand it. However I do agree with you in the larger sense, that we should start by attacking falciparum malaria in Africa. Every year that we wait to start means another half a million children die.

Bill, still thinking and hoping

William Jobin Director of Blue Nile Associates

Submitted by Ricardo Ataide on

Bill, you are 100% right. I don't think it's a good idea to be fighting mosquitoes with chemicals and nets while being chased by AK-47s! It certainly seems impossible to work in places like The Congo or Somalia if you look at them as a whole. But, and this is an honest and naive question: will ALL the villages that qualify as hot spots in those countries be impossible to access? I mean, if you zoom further in on a hot spot country, you see that there are hot spot regions, hot spot villages, right? Will all of those be impossible to work in? They might be, I completely admit my ignorance on that matter since I have never been in either of those countries. Sometimes, even in war-torn countries there are regions and villages which are safer, and identifying them requires the help and participation of local members of the community, which also means that the fight against malaria, in those regions, is extremely dependent on the community. On the other hand there are hot spots in other countries which do not represent such a challenge and I do feel that hitting them hard is the way to go. These are just some thoughts and hopes.

Ric

Ricardo Ataíde

Ron Marchand's picture
Submitted by Ron Marchand on

Much enjoy this strategic discussion: where to start with elimination/eradication - in hot spots or in the periphery of the malaria map. In Vietnam, where I work, I am arguing for the hot spot approach (e.g. in our recent proposal to MESA) which is also the most difficult situation here, namely forest malaria transmitted by Anopheles dirus. This happens to be completely opposite to the official (WHO endorsed) strategy for 'malaria elimination' here, which is based on (hoping to) shrinking the map through the intensification of existing control methods. An. dirus, a largely exophilic and early evening-biting forest mosquito is at present not controlled by any conventional means (ITN/ IRS). In addition, this vector also transmits monkey malaria (P.knowlesi). This means that without developing and testing new vector control methods elimination of malaria from Vietnam and similar Greater Mekong Subregion countries will be impossible. Here I am of course not talking about malaria control in war zones. The point is that going for the (malariologically) most difficult situation forces us to develop and test new methods that will anyway be needed to eliminate malaria at all (if ever).

PS Bill Jobin, would you be so kind to add a reference to that 'recent study about the economic consequences of slavery, colonialism and malaria? Thanks a lot!

Ron Marchand

William Jobin's picture
Submitted by William Jobin on

Yes, he concluded that malaria was more important in the under-development of Africa than was slavery or colonialism. Giving us all the more reason to fight it.

And thanks Ron for your comments about hitting the hot spots in Vietnam. Give me some time to study what I have on An dirus, I have no experience with Asian malaria.

Maybe in the 8,000 subscribers to MalariaWorld there are some entomologists who can help Ron?

But the ref you asked for on slavery etc, is the following:

Sambit Bhattacharyya from Australian National Univ in Canberra,
sambit.bhattacharyya@anu.edu.au

Root causes of African underdevelopment, Journal of African Economies 18(5): 645-780

Question for you Ron - is the Pl knowelsi found often in people in Vietnam ?

Bill - just an engineer

William Jobin Director of Blue Nile Associates

Submitted by Ron P. Marchand (not verified) on

Hi Bill,

Thanks for reflecting. P.knowlesi has in Vietnam thus far only been demonstrated by using PCR, independently from two neighboring areas:
Van den Eeden et al. 2009 - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773789/?tool=pubmed
Marchand et al, 2011 - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3381379/

Pk was found both in mosquitoes and humans as commonly as P.falciparum - but in humans mostly as a co-infection with P. vivax. Also in contrast with the situation in Malaysian Borneo (Balbir Singh et al. 2004. The Lancet 363, 9414: 1017 - 1024) we did not yet encounter symptomatic cases. We do not yet know what is different between Vietnam and Malaysia in this respect. But certainly An. dirus A is capable to transmit both human and primate malarias - since the above publication we also have evidence for Pl. inui, cynomolgi and coatneyi in sporozoite positive salivary glands. Therefore we think this and other forest mosquitoes in the leucosphyrus group pose a special challenge for malaria elimination in SE Asia that will have to be confronted.

(PS - it is almost impossible to avoid the automatic spelling checker in this program changing dirus into virus…!)