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About the Author

Bart Knols
Medical Entomologist (Dodewaard, Netherlands)

Bart G.J. Knols (1965) is the Managing Director of MalariaWorld, the world's first scientific and social network for malaria professionals. He is a malariologist with a Masters degree in Biology and a PhD in Medical Entomology from Wageningen University, the Netherlands. He also obtained an MBA degree from the Open University (UK) in 2006, for which he won the prestigious international ‘MBA Student of the Year 2007 Award’ as well as the Alumnus of the Year Award from the Open University. With 11 years of working experience in Africa he has managed large-scale research and vector control programmes on malaria for ministries, international or national research institutions. He has worked for the UN (IAEA) as a programme manager for three years, has served as a consultant for the World Health Organization, and is currently a Board Member of the UBS Optimus Foundation, the second largest charity in Switzerland. He has published over 130 peer-reviewed research articles, has written 16 book chapters, and has served as senior editor on a WHO/IAEA sponsored book on implementation research. In 2007 he co-edited a best-selling book titled 'Emerging Pests and Vector-Borne Diseases in Europe'. He received an Ig Nobel Prize (2006), an IAEA Special Service Award (2006), and in 2007 he became a laureate of the Eijkman medal (the highest award in the field of tropical medicine in the Netherlands). He has been a member of the Royal Dutch Academy of Arts and Sciences since 2004. Bart held an Assistant Professorship at Wageningen University until April '09 with projects across Africa. He currently directs K&S Consulting, a firm he founded in the beginning of 2007.

Post

If you do what you did, you get what you got (3rd update)

Published 05th April 2010 - 31 comments - 14464 views -

[3rd update, 23 June 2010]

Can we or can we not?: A Feasibility Assessment for the elimination of malaria on Zanzibar

And so the story continues. Chris Cotter from the Malaria Elimination Group alerted me to the following:

The recent success that Zanzibar has achieved in reducing its malaria burden has led the Zanzibar Malaria Control Program (ZMCP) to a point where it faces an important decision of whether to continue sustaining malaria control or to seek malaria elimination. To reach their decision, the ZMCP conducted an assessment to gauge the feasibility of reaching and sustaining malaria elimination from the operational, technical and financial perspectives. This feasibility assessment resulted in a series of evidence-based recommendations, and is the first robust analysis on the feasibility of elimination, therefore forming a strong foundation from which strategic decisions and programmatic shifts in Zanzibar can be made. 

Many local and international experts provided technical advice to the feasibility assessment. This work benefited from the intellectual leadership of the Clinton Health Access Initiative and many members of the Malaria Elimination Group, with financial support provided by the UCSF Global Health Group through a grant from ExxonMobil. 

The final report and recommendations on a way forward were recently presented to the senior leadership of the Zanzibar Ministry of Health and Social Welfare. Conclusions on the short- and long-term challenges of achieving and sustaining elimination are outlined as well as strategies that will be critical for elimination to succeed. The ZMCP has already begun implementing several of the recommended strategies, most notably strategies to enhance surveillance capacity, which are paramount for any elimination effort.

 

On 6 May 2010, whilst on duty travel in Tanzania, I visited the island of Zanzibar where I had the pleasure to meet with the Permanent Secretary of Health, Dr. Jiddawi. He features in the video below.
Dr. Jiddawi is a well-known and respected urologist, and admitted honestly and frankly when we sat down to discuss the malaria situation on Zanzibar that he is not a malariologist. I only had one question for him: Now that malaria is at its lowest level recorded in history, and almost gone, what will be done next?
First, he mentioned that the man at the helm of the US President’s malaria initiative (PMI), Admiral Timothy Ziemer, had visited the island last week. They had been discussing this very issue. Sustaining current control levels seems to be the priority, but vector elimination as such was not mentioned to me. 
Also, estimates are now available regarding the number of people visiting the island from mainland Africa on a daily basis. Six thousand I was told. Six thousand potential parasite carriers that can infect the mosquito population on the island and sustain transmission. When Dr. Jiddawi mentioned the option of screening these visitors for parasites I could pick up a grain of uncertainty in his voice. Clearly, this will be very hard, if not impossible.
Next, he stressed the point of bednet use. People should know that they have to use their nets. ‘Nets, nets, nets’ he said. Only in that manner could the current success be maintained.
But will this lead to elimination of malaria from Zanzibar? Not likely. It was obvious that Dr. Jiddawi was well aware of the critical stage that the island has reached in combatting malaria. That they are nearly there. But also that the hard work is only still to start. Bringing malaria down to very low levels was relatively ‘easy’. Bringing it down to zero remains a massive challenge. 
It is hoped that Dr. Jiddawi and all involved in the fight against malaria on Zanzibar will be given the time and resources to win the end battle and reach glorious success. 
The world is watching, anxiously waiting to see the first chunk of Africa won back from the parasite’s deadly grip. Success on Zanzibar, after all, will boost the morale and confidence of all involved in the second malaria eradication era. 

[end 3rd update]

On 6 May 2010, whilst on duty travel in Tanzania, I visited the island of Zanzibar where I had the pleasure to meet with the Permanent Secretary of Health, Dr. Mohamed Jiddawi. He features in the video below.

Dr. Jiddawi is a well-known and respected urologist, and admitted honestly and frankly when we sat down to discuss the malaria situation on Zanzibar that he is not a malariologist. I only had one question for him: Now that malaria is at its lowest level recorded in history, and almost gone, what will be done next?

First, he mentioned that the man at the helm of the US President’s malaria initiative (PMI), Admiral Timothy Ziemer, had visited the island last week. They had been discussing this very issue. Sustaining current control levels seems to be the priority, but vector elimination as such was not mentioned to me. 

Also, estimates are now available regarding the number of people visiting the island from mainland Africa on a daily basis. Six thousand I was told. Six thousand potential parasite carriers that can infect the mosquito population on the island and sustain transmission. When Dr. Jiddawi mentioned the option of screening these visitors for parasites I could pick up a grain of uncertainty in his voice. Clearly, this will be very hard, if not impossible.

Next, he stressed the point of bednet use. People should know that they have to use their nets. ‘Nets, nets, nets’ he said. Only in that manner could the current success be maintained.

But will this lead to elimination of malaria from Zanzibar? Not likely. It was obvious that Dr. Jiddawi was well aware of the critical stage that the island has reached in combatting malaria. That they are nearly there. But also that the hard work is only still to start. Bringing malaria down to very low levels was relatively ‘easy’. Bringing it down to zero remains a massive challenge. 

It is hoped that Dr. Jiddawi and all involved in the fight against malaria on Zanzibar will be given the time and resources to win the end battle and reach glorious success. 

The world is watching, anxiously waiting to see the first chunk of Africa won back from the parasite’s deadly grip. Success on Zanzibar, after all, will boost the morale and confidence of all involved in the second malaria eradication era. 

[end update]

 

‘Yes we can’ beat malaria

‘It’s a dream come true’, says Zanzibar’s Ministry of Health official Dr. Mohamed Jiddawi in the following video. ‘The beds are empty, it’s good news’, adds Mark Green of MalariaNoMore. And indeed, an all-out integrated attack on malaria in Zanzibar, the idyllic island off the coast of Tanzania, has brought malaria prevalence down to below 0.7%.  Down from the 30-40% where it was a mere five years ago. See for yourself…

What happened in Zanzibar? First, in 2003, the Ministry adopted artemisinin-based combination therapy (ACT), which halved parasite prevalence in the two years that followed. Second, in 2006, long-lasting insecticide treated bednets were introduced on a massive scale. It resulted in a further 10-fold reduction in children carrying the disease. Then came four rounds of indoor residual house spraying, and for the extra vulnerable (infants and pregnant women) intermittent preventive treatment (IPT) was added to the package. Good drugs to cure and prevent malaria. Insecticides to kill the mosquito population. Backed by large sums of funding the world witnessed Obama truism when it gets to beating malaria. Today the island enjoys the tranquillity of a tropical paradise no longer plagued by this ancient scourge.

Einstein’s wisdom

But in spite of these encouraging results, there is reason for concern. Apparently, the recent victory on Zanzibar was history repeating itself. I looked up the data from past attempts to eradicate malaria on the island. Back in 1961, the World Health Organization embarked on a house-spraying programme that continued until 1968. With the same DDT that was used in recent years. By that time, prevalence dropped from >50 to 7.8% and malaria was no longer considered a problem. Spraying was abandoned. By 1973, just five years later, it was back. At a level higher than before the WHO campaign had started:

Data Zanzibar

 

When Dr. Tachi Yamada, President of the Global Health Program at the Bill & Melinda Gates Foundation, wrote a commentary for CNN last fall following his visit to empty wards in Zanzibar, he wrote one striking sentence: ‘Zanzibar -- a relatively small but striking example -- has virtually eliminated the disease over the past five years.’ 

It is the word virtually that is key here. ‘Virtually’ is all the difference between elimination, the complete and sustainable disappearance of the disease, and temporary success. Like that witnessed in the 1960s. Einstein’s words ‘If you do what you did, you get what you got’ apply to Zanzibar’s malaria. Pour large sums of money in the battle against parasites and mosquitoes and you’ll knock it over the head. But you won’t eliminate it.

Zanzibar’s malaria situation in 2010 resembles that of 1968. 

What next?

If Zanzibar succeeds in eliminating malaria it will boost global morale and probably raise unprecedented levels of funding to embark on mainland Africa. There’s a good example: Tsetse flies, that transmit sleeping sickness, were eliminated from Zanzibar a decade ago. Using the environmentally-friendly Sterile Insect Technique (SIT), in which large numbers of sterile male flies are released to mate with wild females that will not produce viable offspring. Call it birth control for insects. Flies were eliminated in Zanzibar. This success fuelled enthusiasm and a large SIT programme is currently underway in Ethiopia, backed by the UN’s International Atomic Energy Agency (IAEA). Small successes breed larger successes.

But for Zanzibar’s malaria the situation is more complicated. Every day, hundreds of people ferry across from Tanzania’s capital Dar es Salaam, many of these carrying the deadly parasite in their bloodstream. Ready to infect the small mosquito population that’s left on the island but enough to sustain transmission at low levels. This necessitates continuous efforts to curb the disease that, sadly, will bring two further problems: History shows that funding levels will not remain at the current level and donor fatigue will kick in. Sooner or later. Moreover, evolutionary forces will catch up with our efforts: parasites will become resistant to drugs, mosquitoes will laugh at our chemicals…

For now, Zanzibar remains vigilant. Clinics use mobile telephones to swiftly communicate local outbreaks of the disease and rapid response teams aim to control these and curtail further spread. But this will be finite...

The only way in which Zanzibar can free itself permanently from malaria is the total removal of the mosquito population responsible for transmitting it. Preferably with a mosquito-free zone in and around mainland Dar es Salaam to prevent mosquitoes from hitchhiking back to the island with the ferries.

The difference between 1968 and today is the fact that science has delivered the tools and strategies to eliminate mosquito populations within the framework of area-wide integrated pest management (AW-IPM). It can be done.

Zanzibar is nearly there, and now is the time to move beyond past successes. Freeing more than one million Zanzibaris from malaria forever or never is at stake. Zanzibar can be proud of its achievements, and its attainment of the MDG6 goal in terms of malaria is to be applauded. But now it has to go the extra mile.

 

Further reading

Bhattarai, A. et al. (2007) Impact of Artemisinin-Based Combination Therapy and Insecticide-Treated Nets on Malaria Burden in Zanzibar. PLoS Medicine, 4(11): e309. Read it here.

 

 


Category: Health | Tags: malaria, history, thnk3, zanzibar,


Comments

  • Lara Smallman on 05th April 2010:

    An inspiring example of what can be done, thanks for sharing this Bart.


  • Daniel on 05th April 2010:

    Really an inspiring post! Keep’em coming!


  • Anindita on 06th April 2010:

    Nice post. Made me read up about the condition in India!
    FYI:India has managed to bring down the number of deaths per year close to just a 1000 after proper treatment. But the number of people getting infected is still very high.


  • Bart Knols on 06th April 2010:

    @Anindita. Thanks for your additional information about India. Sri Lanka is another example of a ‘virtually eliminated’ story. By the mid 1950s, annually some 2.5 million people were infected with malaria. By 1962 there were just 17 (!). India recorded 70 million cases with 800 thousand deaths in 1953. An army of 150 thousand men and women started spraying DDT and by 1961 there were only 800 cases, a reduction of almost 80%. All of this shows that it can be done - but if it is not done in a radical and complete manner malaria will strike back. Its the difference between Taiwan (malaria-free) and Sri Lanka (with malaria)...


  • Jodi Bush on 06th April 2010:

    Great post. I’m really enjoying reading your blogs Bart - I really did not have an accurate idea of the issues surrounding malaria.


  • Bart Knols on 06th April 2010:

    Thanks Jodi. And this is only the beginning - I am building up to reach a climax around blog 15 or so. That’s when it will become even more exciting (I hope). I am currently contacting high officials for interviews…


  • Clare Herbert on 06th April 2010:

    Great to read something so positive. Look forward to reading more.


  • Bart Knols on 06th April 2010:

    @Clare. Thanks. It is indeed a very positive story - but the key message is that we should safeguard against repeating history. This time, with the current global attention for malaria, elimination is the only option that matters. We cannot afford to look back in 2030 having to admit that twice we were nearly there…


  • Olivier on 12th April 2010:

    Bart and Anindita, a quick further comment to the Sri Lanka malaria history: Yes they considered the malaria problem solved in the sixties and stopped the massive elimination effort, which was also very costly and not designed for long term deployment. And then came the post-elimination-(effort)-epidemic, more or less out of the blue (The start of this epidemic was not well documented probably because case detection had (also) been stopped). It must be said that malaria was, for some reason, not as lethal as previously. These days Sri Lanka is once again aiming for elimination…  But a major difference is that this time, malaria has gone down (more or less steadily) over a period of multiple years, likely as a result of the long term control effort (in which most fever cases are tested), possibly combined with improved economic conditions (better housing, etc.). If Sri Lanka can keep up this control system and infrastructure, it could very well roll malaria into the ocean and keep it there.


  • Bart Knols on 12th April 2010:

    @Olivier. You raise a critical issue, namely that general (economic) development is likely to be as important in curbing malaria as the actual fight against the disease. Poverty sustains malaria. Malaria sustains poverty. Better housing leads to reduced contact between mosquitoes and people. Higher income leads to people buying repellents or coils to keep mosquitoes at bay. More cash results in easier access to healthcare and enables people in remote areas to pay for bus fares, etc.etc…


  • Shabina Hussain on 12th April 2010:

    A positive report and a fantastic analysis. Vector control i.e., eliminating mosquitoes that carry the parasite is key to success, along with treatment and elimination of the parasite. Malaria is a huge challenge in that region and effects millions of lives. A sustained effort to eliminate the disease must continue.


  • Peter Ward on 13th April 2010:

    As part of my work leading the SMS for Life project in Tanzania, I’ve had the pleasure of meeting Fabrizio Molteni who has been running the Zanzibar work for the last 10 years or so.

    Zanzibar is a special case because of its physical isolation. If we were able to stop mosquitoes from flying over country boundaries it would be possible to do the same in other countries—but we can’t. Therefore there have to be initiatives that cross borders to meet the challenge.

    ACTs are a great way to start, because they kill the parasite (for now at least). We need to make sure that everyone who needs these drugs gets them: something SMS for Life can help make happen. With this plus bednets (and a culture change to prevent them from being seen as only for women and children), we can dramatically reduce the incidence of malaria.

    But even though it’s easy to say, it’s not necessarily easy to do. I salute those who are working in these areas and look forward to seeing Zanzibar-type good news elsewhere as multiple countries in sub-Saharan Africa kick off these types of initiatives.


  • Bart Knols on 13th April 2010:

    @Shabina, thanks for sharing your views and the need for sustained efforts to eliminate malaria.

    @Peter. Much appreciated, it is nice to receive feedback from the people directly involved in the field.

    Although Zanzibar is an island, there are ‘islands’ on mainland Africa. Malaria anywhere north of Khartoum (Sudan) is strictly connected the Nile river. As was done in Egypt shortly after WWII, a stringent and well-organised campaign based on larval control could roll back malaria from Wadi Halfa (border with Egypt) all the way down to Khartoum. That’s more than a million people freed from malaria…

    Similarly, along the Sahelian belt, numerous areas where malaria transmission is highly seasonal and focal, massive impact could me made.

    Along the entire African coast, malaria can be eliminated from islands. Sao Tome and Principe should have been dealt with in the 1960s, but wasn’t and is now only starting to move towards elimination.

    Much work, hard work, but it can be done…


  • Iris Cecilia Gonzales on 13th April 2010:

    Thanks for this post Bart…Honestly, it’s the first time I heard about Zanzibar. Pardon me. This is a learning point for me.


  • Bart Knols on 13th April 2010:

    @Iris. Well, you can’t complain in the Philippines, but Zanzibar is one of the most beautiful places in Africa. Imagine it free of malaria - this will mean a huge boost to the economy of the island in terms of tourism income…


  • Bart Knols on 15th April 2010:

    I updated the original blog with an extra clip from Zanzibar, showing how the island is using text messages to centrally record the number of cases across the island. Worth a look…


  • Peter Ward on 22nd April 2010:

    @Bart, thanks for sharing more of your thinking. I think your ideas are interesting. Similarly, malaria was eliminated from Italy after WWII by flooding the whole country with drugs, available free from street kiosks. But of course the disease moves on and what’s permissible also changes—the drugs that worked in Italy won’t work now and those that do (ACTs) are only available on prescription.

    BTW, I’m not sure how much of a deterrent to tourism malaria is on Zanzibar currently. It seems to be very attractive to tourists despite the malaria. And many (most?) people who go to Zanzibar also go onto the mainland. For tourists, Malarone is an effective precaution. More problematic, at least for the last-minute holidays, are yellow fever and hepatitis that need inoculations to be completed in good time. I’m not saying we shouldn’t completely eliminate malaria on Zanzibar, but simply that I don’t think it’s a major tourism issue. It’s much more important for the inhabitants smile.


  • Bart Knols on 23rd April 2010:

    @Peter. The complexity of malaria eradication in Italy was more than drugs, it was holistic change in all fields, aided by drugs and good insecticides. The point is: It worked. If it worked there, than it can work elsewehere. Maybe you are correct ref tourism, but who has any figures? We don’t know. It is a point in South Africa.

    If it isn’t a tourism issue now, it can be in the future. Imagine marketing the island as completely free of malaria… It may not keep people away right now, but it may attract them more so if that’s the case, wouldn’t you agree?


  • Marit on 29th April 2010:

    Hi Bart!
    Thanks for this nice post. I think it is really important to emphasize the difference between “virtual” and actual elimination of malaria. Considering that even on islands it is very difficult to really eliminate malaria, efforst to fight malaria on the African continent will require very robust and radical approaches.

    Although I like that you point out that we have the tools to successfully eradicate this terrible disease, I am worried about the long term efficacy of our current tools. Drug resistance in parasites and insecticide resistence in mosquitoes is a real threat to sustainable malaria control.
    What I don’t understand is why the research emphasis (and the majority of the money) is focussed on finding new drugs and insecticdes which will ultimately again face problems with resistance. (Like you said: if you do what you did, you get what your got.)
    Why do you think there is so little focus on very new tools, such as house design, larval control or biological control of mosquitoes such as fungi?
    And do you consider the current tools sufficient to really eliminate malaria in the long run?


  • Bart Knols on 29th April 2010:

    @Marit. You raise vital questions. Long-term use of drugs and insecticides will, beyond any doubt, lead to resistance, and then we’re back to square one. What is strange is the fact that we don’t seem to learn from historical failures (resistance) but equally not from historical successes.

    Past successes in eliminating malaria were not based on long-term interventions, but ‘dealing with it’ over a few years maximum. Anything longer than that, and evolution will outwin us. This happened, for instance, on Sri Lanka. Malaria was nearly eliminated, but then resistance to DDT kicked in.

    Anything we do at the moment is long-term. Nets, drugs, and so on. All leading to resistance. Although the world frantically searches for alternative chemicals, there is regretfully not an open vision to search for sustainable solutions like the ones you propose. House modification was one of the earliest successes booked in malaria control, larval control (or larval source management) was key in eliminating malaria from the USA and many other parts of the world. Right now in Africa there’s only a handful of projects and people trying to revive this successful approach…

    Biological control still resides in the ‘Hippy’ arena, and although biological control of pests in agriculture is now widely accepted and practiced, the same is not taken seriously by many in the field of malaria, notably by those searching for new insecticides… Hopefully the day will come that this will change. Perhaps we need to move through more cycles of the resistance treadmill before that time is there.


  • Bart Knols on 08th May 2010:

    On 6 May I had the pleasure to meet with the Permanent Secretary of Health, Zanzibar. I have updated my blog following this meeting.


  • Bruno Moonen on 17th May 2010:

    Malaria Elimination in Zanzibar: A Feasibility Assessment

    Due to the recent success that Zanzibar has achieved in reducing its malaria burden, Zanzibar finds itself at the crossroads of deciding whether to continue sustaining malaria control or to seek malaria elimination. To reach their decision, the Zanzibar Ministry of Health and Social Welfare and the Zanzibar Malaria Control Program conducted an assessment to gauge the feasibility of reaching and sustaining malaria elimination from the operational, technical and financial perspectives. This feasibility assessment resulted in a series of recommendations, and is the first robust analysis on the feasibility of elimination, therefore forming a strong foundation from which strategic decisions in Zanzibar can be made.

    The report can be found under the January 2010 resource of the month page at http://www.malariaeliminationgroup.org/resources/resource-month


  • Bart Knols on 17th May 2010:

    @Bruno. Many thanks for providing the link to this document. The core conclusion of this report is that elimination is feasible but very challenging.

    Although it is envisioned that transmission can be brought down to zero with sustained if not intensified vector control operations, it is at the same time acknowledged that the constant re-introduction of parasites (by humans travelling to the islands) is making long-term success questionable.

    The report does not touch on full vector elimination - the only durable and lasting solution to the problem. Why was this not considered?


  • Bruno Moonen on 21st May 2010:

    Bart,
    let me first clarify that I am not at all a specialist in the field of malaria entomology. The reason why the elimination of the vector was not considered is therefore based on advice from external specialist and/or guidance from international bodies like the WHO. As far as I understand (but I would be very happy to be corrected on this because I of course fully agree with your statement that full vector elimination is a lasting solution in an environment with constant importation of infections. References more than welcome!) there a few examples of successful elimination of the vector and, in most cases, these vectors were either not indigenous or not very efficient in transmitting malaria to start with. In the case of An Gambiae, I am not aware of any successful project in Sub-Saharan Africa where vector elimination was achieved. This does of course not mean that we should not try it if there is evidence that certain methods can achieve it.
    Bruno


  • Bart Knols on 21st May 2010:

    @Bruno. Many thanks for your further input. I’d be happy if you could email me the names of the experts that decided against vector elimination. By doing so, after all, they acknowledge that malaria elimination from Zanzibar will not happen (due to the constant importation of infections and a (albeit small) residual vector population.

    Elimination in Africa has taken place in Egypt (An. arabiensis). Reference: Shousha AT. Species-eradication. The eradication of Anopheles gambiae from Upper Egypt, 1942–1945. Bull World Health Organ1948; 1:309–53.

    Outside Africa, vector elimination was accomplished in Brasil against an infestation of the African malaria vector An. arabiensis over a 54,000 sq km area. In their new homeland, these African mosquitoes were actually much better at transmitting malaria then back in their native Senegal. See for instance: Killeen et al. (2002) Eradication of Anopheles gambiaefrom Brazil: lessons for malaria control in Africa? Lancet Infectious Diseases, 2, 618-627.

    Considering the fact that this African invasion was cleared to the last mosquito using mostly larval control, why would such an approach not work today? There are 14 malarious countries in Africa smaller than the 54,000 sq km that were cleared 70 years ago. Zanzibar island is a mere fraction of this…


  • Bart Knols on 27th May 2010:

    @Bruno. My post on Fred Soper and the campaign against the African malaria mosquito in Brazil is live now. See it here: http://development.thinkaboutit.eu/think3/post/the_man_who_saved_brasil/


  • Graham Kloke on 17th June 2010:

    Hi Bart,
    I have read about you and your fascinating work in ‘odour control’, and I believe it is a truly innovative ‘green’ way to malaria and other vector control. The work by Glynn Vale has shown the practical efficacy of this technique with the tetse fly. I was interested to read about the elimination of An. gambiae from Brazil by Soper. I knew about this and it was one of the first highly successful IRS projects undertaken in the world at that time. A practical control measure first expounded by de Meillon of South Africa. As you know when de Meillon first demonstrated this to Soper he ridiculed de Meillon. After Brazil he sent his apologies to de Meillon. Also as I am sure you are aware, it was recently confirmed that the vector was An. arabiensis, not An. gambiae as originally thought. As such it did not penetrate deeply into the forests which facilitated ‘easier’ control of this vector. this does not take away the magnificent work done by Soper and his teams, but demonstrates the necessity of understanding vector bionomics in relation to control and hopefully, eventual elimination. I must confess, having worked in malaria vector/control in Africa for over 20 years, I am sceptical of the WHO having set timeframes to elimination, there are just too many confounding issues that have to be dealt with first before the way can be paved for elimination. My first time in seeing your blog, I think it is great!


  • Bart Knols on 17th June 2010:

    @Graham. Many thanks for your insightful comments.

    Having worked on odour-baited trapping for malaria mosquitoes and tsetse (in Zambia) for nearly 2 decades, I have come to believe that such traps will not serve as good tools for control let alone elimination. Their initial role should be in monitoring vector populations - if that can be done (especially at low population densities) than that would be a big accomplishment.

    Please note that the majority of the Brazil campaign was not IRS but larval control in breeding sites using Paris green. They did make use of pyrethrum, but as you know, this had hardly any residual activity.

    And yes of course I know of De Meillon - in fact I asked Maureen Coetzee not so long ago about the paper in which he first describes indoor resting of African anophelines, laying the foundation for IRS. He should be credited for this (in fact I did in my book that was published last november).

    Yes, as written in the comments under ‘The Man Who Saved Brazil’ it was arabiensis that invaded Brazil. As you know, both gambiae and arabiensis are vectors that prefer to breed in open, sunlit, waterbodies. That arabiensis did not breed in the think jungle of Brazil is true, but it DID breed in 54,000 sq km of open terrain, with swamps, marshes, floodplains etc.

    As has been discussed in the Soper blog, I would not imagine targeting malaria vectors in the forests of Congo at this stage, but the openness and accessibility of much of the Sahelian zone is highly suitable for larval control.

    That such campaigns have been tried and faltered is not an issue regarding the tool (use of larvicides such as Bti) but entirely an issue of implementation (i.e. it wasn’t done with enough rigour). And that’s where the challenge lies: not in the tools, but staging a war in the same way as Soper succeeded doing in Brazil.

    What do you think, is this possible in the Africa of today?


  • Bart Knols on 23rd June 2010:

    I have added a 3rd update on the Zanzibar malaria control/elimination effort (23 June 2010)


  • Bart Knols on 24th August 2011:

    @Kilimanjaro treks - thanks for your kind words. Unfortunately, Zanzibar is still not ready for vector elimination. Instead, so I am told, it will be tried to have Zanzibaris take prophylactics when they visit the mainland, to avoid being infected and taking parasites back to the island. I have serious doubts that this will work…


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