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The inherent waste in ephemeral methods such as bednets or indoor spraying, compared to the accumulating benefit of land reclamation

February 18, 2014 - 14:06 -- William Jobin

When Martinho Somandjinga, Manuel Lluberas, Joaquim Canelas and I started the US PMI in Angola in 2005, the excitement and pride of our accomplishments carried us along for the first couple of years. Sure we spent over two million dollars in one small province each year, but it seemed worth it.

But as the years went on, and before we sprayed each of these houses, and we had to ask the folks to move all their food and furniture out of the kitchen or dining area, I couldn't help wondering if it might not be smarter to control the mosquitoes with another method, something more permanent. Like maybe reducing the number of breeding sites near the homes. The breeding was quite focal, and also very seasonal, closely related to the rains. And the land was flat, with lots of marshy areas in the small floodplains along the intermittent streams. Also there was a simple irrigation system with lots of flooding problems in the rainy season as it lacked even a simple drainage network to complement the irrigation ditches.

In 2006 we had to do the spray again, for another 2 million dollars. And again in 2007. And in 2008, and every year since, for 9 years now. The US PMI has now spent about $200 million in that part of Angola, and about a third was for indoor spraying - roughly $70 million. The waste in all this is that the effect of that $70 million lasts about a month, then it is gone.

Suppose we had started spending half of the money on permanent mosquito control measures such as reclamation of the floodplain swamps so they could plant crops there? And digging simple drains to complement the irrigation ditches?

Who would do this work? Obviously it is the kind of thing that local farmers and laborers could do. All they need is a pick or shovel. Even I know how to dig a ditch, and I'm not much of a farmer.

Land reclamation would not eliminate the need for spraying in truly wet years, but it would reduce it drastically. And each year we could have built out more and more breeding sites - permanently. Meaning more years when mosquito production is minimal.

That is another real advantage of land reclamation and drainage for mosquito control. Because its effect is permanent, each year the covered area expands. However spraying has an effect for only a few months, then we are back to Zero, and it has to be repeated - every year, forever. That means purchasing biocides, buying new spray cans, and new protective gear for the spray crews. And every year the homeowner has to move everything out of the house before the spray. After 2-3 times it starts to produce resentment against the spray campaign.

Another advantage of permanent land reclamation is that by reducing the frequency of spraying, it takes off the pressure toward the Resistance Treadmill.

We could have done a lot of land reclamation in Angola by now. with even half of that $70 million. And who would get the direct financial benefits from the money spent on ditching ? Mainly the local subsistence farmers who could be hired in the off-season. But who benefits when we spend $2 million each year on biocides and spraycans ? The chemical company Syngenta, or whoever sells the new carbamate that has to be used because of the mosquito's resistance to pyrethroids, and also the Hudson Company of Chicago who makes the spraycans. I have nothing against either company, but I would prefer to see the money go to the local farmers.

While laborers are also hired for spraying, they have to do the work quickly in a matter of a month or so. In contrast the ditching and filling of depressions can be done gradually over the entire year and is thus a much better job to have, instead of the temporary spraying job.

And one more practical advantage - avoiding the Immunity Dilemma. Malaria programs often fail after several successful years. If the program was based on ephemeral methods such as spraying, then the young children have no immunity against malaria and will suffer enormously. But if the methods used were permanent and durable, the temporary lapse of effort will have little effect.

So to summarize - the benefit of permanent methods such as land reclamation vs ephemeral methods such as spraying, are:

1. Fewer years when spraying is needed
2. Reduced pressure towards the Resistance Treadmill as spraying is reduced
3. Increased land for local agriculture
4. Better jobs for local workers to do the ditching
5. Less disruption of homes during spray operation
6. Reducing the Immunity Dilemma
7. Accumulated area of eliminated breeding sites

This last benefit is important, the accumulated impact from such permanent methods. I think it also explains why malaria does not return to places like Italy or the Holy Land, even though there are plenty of introductions of vectors and infected peoples. As the decades pass, the remaining area of breeding sites shrink and almost disappear.

It is one thing to be pleased with the quick effects of indoor spraying, but it is another thing to keep on doing the same thing forever. Gradually introducing permanent improvements will also gradually reduce the costs, and eventually build out anopheline breeding. In some respects, it is even an Exit Strategy - maybe even before the advent of the mythical vaccine.

Bill, ready with my pick and shovel

Comments

Submitted by Ricardo Ataide on

Hi Bill,

Really interesting! It is not everyday that somebody acknowledges that a lot of money could have been better spent.

Do you have any data on malaria transmission, the changes in malaria immunity in the community and on the fitness and resistance patterns of the vector populations?

Ricardo Ataíde

William Jobin's picture
Submitted by William Jobin on

Thanks for your query Ric,

The answer is complex, but I will give you the bad news first. I have worked with WHO since 1963, and helped start the US PMI in 2005, but finally gave up in frustration because of the amateur way they were evaluating the impact of the PMI and the RBM programs.

It is shocking that billion dollar programs for suppressing malaria do not evaluate their impact in an organized way on the mosquitoes, nor on the parasites, nor on the infected people. If you can find any since 2005, please let me know. Your request for sophisticated evaluations of immunity and vector characteristics is quite justifiable, but nobody is doing it.

If any of our readers can prove me wrong, please do so - right now. Please.

It is logical to expect that a periodic sampling of prevalence in a sentinel population in the treated countries, in comparison with similar samples from untreated countries, would be part of the programs. And it would be normal to conduct before and after comparisons too.

Instead we get reports on all-cause mortality which are useless since many factors contribute and since a general decline in deaths of children in Africa was going on long before the malaria programs started.

Finally we get maps like the ones generated in the last copy of Lancet, by knowledgeable people who are starved for solid data on malaria in Africa. I would think a solid evaluation of the impacts of these global programs would be a minimum contribution that we should expect from WHO. But it hasn't happened.

Better news later, please be patient.

Bill

William Jobin Director of Blue Nile Associates

Submitted by Ricardo Ataide on

It is a shame really... We can only hope that all the interventions being implemented now, either by the WHO or otherwise, already contemplate a little bit more than just the "Yippee Ki-Yay" attitude.

On the look out for better news!
Ric

Ricardo Ataíde

William Jobin's picture
Submitted by William Jobin on

Thank you Ric for your patience,

but I want to add one more piece of bad news before getting to the good news. It is about the problem of growing populations of children at high risk, in countries with good malaria suppression - children who have no immunity to malaria.

This dilemma or perverse problem has been noted from the very first programs which attempted to suppress malaria, but could not maintain the suppression indefinitely - usually indoor spraying. So when the program collapsed after 5-6 years, there was a sudden surge in fatal malaria cases among the children in the previously protected population, and adults too.

We experienced it in Sudan, as detailed by Jose Najera, the malaria guru of WHO. After holding malaria prevalence below 1% for almost 10 years, our program was destroyed by the new dictator in Khartoum when he stole our hard currency reserves. The parasite prevalence in children jumped from 0.5% to 15% in 1990, and then to over 30% when the heavy rains came (see p 19 in my Blue Nile Monograph One 2010, which you can browse on Amazon.com).

The problem is the inherent instability of malaria suppression based on the WHO strategy of bednets, drugs and biocides, all of which require continuous expenditures of hard currency. Also they lead us inexorably to the Resistance Treadmill, and are thus ephemeral - bound to disappear.

This Immunity Dilemma is inevitable, especially with Donor Fatigue, yet neither WHO nor RBM nor PMI have come up with a solution. When will they ever learn?

Bill

William Jobin Director of Blue Nile Associates

Submitted by Ricardo Ataide on

That's a great example, Bill.

Another thing we cannot forget is that in countries where transmission is relatively high and stable, women in their first pregnancies are also at risk (since the placenta seems to select for the appearance of parasite antigens, associated with a certain adhesion phenotype, to which the body has no immunity against). Multigravidae have already developed enough immunity against these parasite antigens to be able to deal with an infection. I fear that when malaria prevalence starts dropping then the proportion of multigravidae that have developed these antibodies will also decrease. That means that a resurgence of malaria would also not bring good news to these women and their offspring, for they would be 'primigravidae' in terms of immunity to the parasite antigens that bind the placenta.

Do you have any information regarding what happened with the pregnant population in Sudan at the time when you had a resurgence of malaria?

Ricardo Ataíde

Jeff Juel's picture
Submitted by Jeff Juel on

There is a fascinating paradox in play surrounding Bill's lament.

There is no way that WHO, USAID, or the Gates Foundation will seriously implement LSM to eradicate malaria - or allow anyone else to do it.

Can you imagine the backlash and horrific bad publicity if some organization actually achieved regional eradication in some malarious area in Africa using 20th century LSM? (As was done in Panama, Havanna, Palestine...)

"The establishment" would look worse than The Tuskegee Institute and USPHS with their Tuskegee Study of Untreated Syphilis in the Negro Male (1932-1972).

Not utilizing LSM in Africa today parallels the USPHS not administering penicillin to the poor African American sharecroppers in their infamous Tuskegee study.

History repeats itself, and in this case it is truly tragic.

Jeff Juel, PE
www.jueltide.com

Jeff Juel's picture
Submitted by Jeff Juel on

The Tuskegee Study of Untreated Syphilis in the Negro Male was a fascinating and tragic medical study began in Alabama in 1932. The United States Public Health Service (USPHS) and The Tuskegee Institute (now known as Tuskegee University) collaborated to conduct the Tuskegee Study of Untreated Syphilis in the Negro Male. (This was the formal title of the study.)
In 1932, syphilis was effectively untreatable, however by the 1940’s, penicillin was available and it was very effective for treating and curing syphilis. In spite of the readily available cure, the Tuskegee study went on for decades with 400 Negro male subjects not being treated for their syphilis infections over the duration of the study.
The people who participated in the study were not intentionally infected with syphilis as part of the study. (They acquired their infections on their own prior to the study.) They had latent infections, and they were told by the researchers that they had “bad blood”. They were not aware that they were infected with syphilis.
What is astounding about this is the medical ethics of the study: How could anyone with a conscious knowingly allow this study to continue after penicillin was available and known to cure syphilis?
When syphilis was untreatable, the study made some sense. The scientific data obtained by this study could be used to document the disease, advance science, and make the search for a cure a higher priority. After penicillin was known to be an effective treatment for syphilis, what could have possibly motivated the United States Public Health Service and The Tuskegee Institute to continue the study?
I theorize that this study continued for years after the advent of penicillin primarily because stopping the study and treating the subjects for their infections would be difficult to explain. People would ask: “Why didn’t you give the people in the study penicillin sooner?” The longer that the study went on; the more politically awkward it became to shut it down and cure the participants’ syphilis with penicillin.
The fact that no individual bureaucracy was responsible for the study may have contributed to the USPHS and Tuskegee University failing to take action. This may be functionally similar to what social psychologists refer to as “the bystander effect”. With the bystander effect, the greater the number of bystanders, the less likely it is that any one of them will help a person in distress. Two organizations and their numerous upper-level managers constitute a crowd of bystanders.
I am not aware of a controlled study, but I hypothesize that in the classic scenario, the probability that one of the bystanders will eventually take action is inversely proportional to the square of the elapsed time. Someone actually doing something becomes increasingly awkward (and unlikely) the longer the bystanders remain inert.
The Tuskegee Study travesty was a variation on the bystander effect – I call it “the bureaucracy effect”. With the bureaucracy effect, the greater the number of bureaucrats…
As the years passed, the magnitude of The Tuskegee Study travesty increased exponentially. Shutting down the study became more and more unpalatable with each passing year. The USPHS and The Tuskegee Institute only stopped the study in 1972 after a determined and persistent whistle-blower along with a journalist and a front-page NY Times story brought this study to the public’s attention.

The reason I bring this up is that I believe that there are historical, political, & psychological parallels between:
1) the United States Public Health Service and The Tuskegee Institute between 1945 and 1972; untreated African-Americans infected with syphilis; and the failure to cure infected African-Americans by administering penicillin.
And
2) USAID, WHO, and other organizations circa 2014; the continuing malaria epidemic in Africa; and the failure to utilize vector control via larval source management to reduce the incidence of Malaria in Africans.
Penicillin is not a cure for Malaria, however we DO know how to eradicate Malaria (at least regionally), and we’ve known how to do it for over a century. Regional malaria eradication has been accomplished a number of times in various places around the World: Havana in 1898; Panama in 1900; Palestine in 1930; and America by around 1950 – to name a few of the more well-known campaigns in the war on mosquitoes and mosquito-borne disease.
These campaigns primarily relied on vector control to reduce the transmission of Plasmodium - the parasite that causes malaria. Vector control is a collection of actions that reduce the population of Anopheles Mosquitoes in the area of interest. Anopheles Mosquitoes are the organism or “vector” that is responsible for the spread of malaria within a human population; eliminate the vector and there will be no new infections of plasmodium.
Prior to 1950, the key measure used in all successful vector control campaigns was larval source management, or LSM. LSM involves identifying the locations where mosquito larvae can develop into adult mosquitoes, and removing or modifying the water so that it is either not accessible or it is unsuitable for mosquito larvae.
After 1950, DDT was the method of choice for vector control. DDT was relatively inexpensive to produce and its application was reasonably efficient. It controlled larvae as well as adult mosquitoes. It’s low cost, effectiveness, and apparent safety led to overuse. In 1962, Rachel Carson’s book Silent Spring described possible unintended consequences that could materialize from of the overuse of pesticides.
There are serious problems caused by unrestrained use of any pesticide - including DDT. In time, the target organism will develop resistance and the population will rebound. Relying exclusively or primarily on DDT for vector control for any length of time is a recipe for disaster.
Larval Source Management including flood control and drainage infrastructure does not have this inherent weakness. Mosquitoes will never evolve into an organism that does not have an aquatic larval stage in their life cycle.
Imagine that beginning next year, USAID and/or WHO or some other organization employs classic 20th century larval source management techniques and they succeed in eradicating anopheles mosquitoes in some region of Africa. It would be a bit like the Tuskegee researchers using penicillin to cure syphilis in five of their untreated 400 black males in 1970. People would ask: Why didn’t the you do this 20 years earlier? And; When are you going to treat the other 395 study participants?”
If a vaccine or some high-tech solution for malaria materializes in the near future (and it actually works - and can be distributed to a large population - and it does not have serious side-effects) there will be deafening applause and awards. On the other hand, it is possible (and likely?) that a viable high-tech way to eradicate malaria in Africa will never be found.
Imagine that while waiting for a vaccine or some other silver bullet, one organizations uses proven (along with new & innovative) larval source management techniques to successfully eradicate malaria in a formerly malarious region in Africa. Can you imagine how anticlimactic this would be?
I believe that this explains some portion of the resistance to using classic larval source management in Africa. Successful eradication using LSM would be a PR disaster for some very powerful organizations.
While there are interesting parallels, it is not entirely fair to compare the Tuskegee Study to the present day campaign to combat malaria in Africa. There are differences:
- The Tuskegee Study was simply a study. The study was never intended to cure anyone of disease.
- The Tuskegee Study only affected a couple hundred poor black sharecroppers, whereas USAID’s malaria work affects several hundred million poor black Africans.
- Administering penicillin is remarkably simple. Successful LSM is complicated and it requires significant engineering work and a considerable investment in drainage and flood control infrastructure.

The bottom line is that LSM was used successfully 50 to 100 years ago in a number of locations. With all of the technological advancement that has occurred in the past decades, we should be able to use LSM to regionally eradicate malaria – as well as other mosquito-borne diseases in many populated areas in Africa.
The bystanders need to take action.

Jeff Juel, PE
www.jueltide.com

William Jobin's picture
Submitted by William Jobin on

SPRINGS IN THE DESERT

The Good News for Malaria Suppression is that many countries in Africa are experiencing rapid rates of economic development, and furthermore economic development and suppression of malaria seem to be mutually self-reinforcing. Although it has a large impact on this mosquito-borne disease, this Good News is not related to immunology or drugs, but to economics and resource development.

For background, the current economic engines of development in Africa are based on natural resources, appearing like Springs in the Desert. These engines of development in Africa are oil, precious minerals, and hydroelectric power. Countries blessed with these natural resources are now experiencing growth rates in economic productivity as high as 19% per year !

(Ethiopia = 11%, Ghana = 11%, Liberia = 19%, Mozambique = 11%, Rwanda = 13%, and Zambia = 12%).

For comparison, the US gets excited when its annual growth rate goes above 4%.

The numbers above were reported by the World Bank for the period from 2007 to 2011 - annual increases in per capita Gross Domestic Product. I didn’t report the growth rates from oil countries like Angola and Chad which are even higher, but in which the wealth is not shared very well.

Note that except for the oil countries, most of these countries are relatively stable and democratic (Liberia and Ghana) and – very important – they are also successfully suppressing malaria, with the help of the US Presidential Malaria Initiative and also the Roll Back Malaria program of the UN.

On a broad, historical scale, we have seen that countries which undergo these high rates of economic development soon build malaria out of the picture. Thus once malaria is suppressed, it does not return.

Improving Mosquito Ecology

Firstly they change the mosquito ecology by reclaiming swamps and marshy land for agriculture. See Italy, the Holy Land, Egypt and the other Maghreb states of North Africa.

Improving Human Ecology

Secondly, during their economic development they change their human ecology by improving housing with closed eaves and window screens.

Thirdly, those countries with hydroelectric power resources develop reliable and affordable electricity in areas near the dams, so that people can sleep under electric fans during the hot and humid malaria seasons. Electricity also has other important and very direct benefits for fighting malaria and for improving health in general; for lighting laboratories and health units at night, and for refrigeration to store medicines and vaccines.

Introducing Reliable and Affordable Electricity to the boondocks

See the Tennessee Valley Authority of the southern USA, Puerto Rico, Tajikistan. Ghana, Zambia, Sudan, Egypt and Uganda. This process of electrification provides zones of improved human ecology in close proximity to the transmission lines, with freedom from malaria and prosperity in each of the following countries with numerous or large hydroelectric dams.

TVA – 30 dams on the Tennessee River and tributaries
Puerto Rico – 25 dams in the central mountains
Tajikstan – 12 dams along Amu Darya River
Ghana – Akosombo Dam on the Volta River – I,000 Megawatt
Zambia – Kariba Dam on the Zambezi River – 1,270 Megawatts
Sudan – Roseires and Merowe Dams on the Nile River – 1,000 Megawatts
Egypt – Aswan Dam on the Nile River - about 500 Megawatts
Uganda – Bujugali Dam on the Upper Nile River – 300 Megawatts

If the malaria people in these countries are aware of the linkage between economic development, malaria suppression and the availability of electricity, they can map out a strategy of malaria suppression starting in these areas around the dams and along the transmission lines. In these areas they can hold the malaria down with gradually decreasing effort, which they can then devote to expansion of the protected area. They can lobby their National Power Agency for expansion of service to cities and towns along the high-voltage transmission lines.

Avoiding the Resistance Treadmill and the Immunity Dilemma

The trick here is to maintain suppression in these areas long enough to get off the Resistance Treadmill, and thus avoid the Immunity Dilemma. Countries which have done this include all the countries in the temperate zone such as the USA and Europe, as well as the countries I previously mentioned around the Mediterranean Sea.

Southern Africa has already reached this stage, including Namibia, South Africa, Botswana and Swaziland. Zimbabwe should be there too, but they have been ruined by the senile Mugabe and his military gang.

How long does malaria have to be suppressed before one gets off the Resistance Treadmill ? It depends on the countries’ rate of economic development. For countries in the heart of Africa however it also depends on their geographical neighbors who might not be developing as quickly.

One River Basin at a Time

Probably development and suppression of malaria will advance most rapidly in the major river basins of Africa as they develop their hydroelectric capacity, namely the Nile River, the Zambezi River, the Senegal River and the Niger River.

I think this is a good Exit Strategy and we should push it now.

Bill, the engineer

William Jobin Director of Blue Nile Associates