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How did USA get rid of malaria?

February 10, 2014 - 15:30 -- William Jobin

There are several recent papers examining the way that the US gradually suppressed and then eliminated malaria from the southern states which were sub-tropical, and also from the northern states in which summer-time malaria had always been a problem.

According to government publications from the Tennessee Valley Authority in 1946 right after the Second World War, they had suppressed malaria in the Tennessee River Valley by careful construction and operation of the 19 new reservoirs they built on the Tennessee River after 1930, along with improved drainage works, larviciding, improved housing with screens, and improved health services, These techniques had been derived from earlier state programs dealing with malaria around small impoundments. They were then expanded under the Works Progress Administration (WPA), a public works program for fighting the Great Depression of the 1930's by employing people for drainage and other public works, and then again during the Second World War under what is now the Centers for Disease Control of the US Public Health Service. As soon as DDT and chloroquine were introduced after the war, the disease quickly disappeared.

However a paper by Humphreys from 1998 in Parassitologia v40 indicated that instead it was the social changes - such as migration out of the impoverished lowlands of the South, and improved economic developments - which caused the decline in malaria and which were more important than the attacks on mosquitoes. Also Kitchens reported that there was in fact a temporary increase in malaria around the TVA reservoirs (in Journal of Economic History 2013).

Then a few years ago, Sledge and Mohler reversed this explanation, saying that in Alabama these social and economic changes were not the reason for disappearance of malaria. They concluded that the public health interventions, especially drainage works, caused the decrease in malaria, and this led to the observed improved economic development (Sledge and Mohler 2012 -Eliminating malaria in the American South - doi: 10.2105/AJPH.2012.301065

Most recently Kitchens again weighed in with a study of the state of Georgia in which he concluded that the decline in malaria was chronologically linked to the drainage works of the WPA, which caused a large decline in malaria, just before the introduction of DDT and chloroquine which then eliminated the disease (in Explorations in Economic History 2013).

Obviously there is room for more exploration of this history. Such exploration would help us a great deal as we try to find a way out of the malaria morass in Africa. There are at least two controversies in the American story which are relevant to Africa: does suppression of malaria result in improved economic development or is it the reverse, and should drainage and water management be a part of the attack or should we depend solely on biocides, drugs and bednets?

We are fortunate that historians, sociologists and economists are also examining malaria suppression. They add a great deal to the opinions of us malariologists who might be too close to our problem. I thank them,.

Bill

Comments

Andre Siqueira's picture
Submitted by Andre Siqueira on

Dear Bill,
Thanks for this great post! I guess it is a very important topic that desearves a lot of attention, how to achieve progress on malaria elimination (and in several other health problems) by improving living conditions. By examining these past experiences we might be able to realize that by combine efforts it could be able to achieve several favourable outcomes in a more sustainable and cost-effective way. Thanks a lot and lets continue this effort.

Andre M. Siqueira

William Jobin's picture
Submitted by William Jobin on

Hi Andre,

You have hit on a couple of important points we should think about in attempting to suppress malaria. One is that it is more economical to attack several health problems at once, if they have a common theme. For that reason we attacked all water-associated diseases in the Blue Nile Health Project in Sudan; malaria, schistosomiasis and diarrheal diseases. Each lab technician could diagnose all three diseases. Improved water management through better irrigation techniques and improved drainage reduced mosquitoes and snails at the same time.

We have to deal with another point - the high cost of maintaining malaria suppression for generations. Which means we need to demonsrate the profitability of malaria suppression, and we also need an Exit Strategy.

I like your thinking Andre, keep at it.

Bill

William Jobin Director of Blue Nile Associates

Jeff Juel's picture
Submitted by Jeff Juel on

This is a marvelous post!

Water management - including flood control - was THE KEY to eradicating malaria in the US. Coincidentally, sound water management is integral to economic development.

Flood control & drainage infrastructure supports economic development. Economic development finances expanding flood control and drainage infrastructure. This is a superb feedback mechanism for incidental malaria control. I suspect that this feedback loop played a major role in the rise of civilization in Mesopotamia. (But I digress... this is a topic for Anthropology World.)

The American Society of Civil Engineers estimates that there are 100,000 miles of levees in the US. That is enough to encircle the globe four times! This undoubtedly contributed to a reduction in mosquito breeding in the US. In 2013, the ASCE issued a report card on America's infrastructure and they gave our levees a D minus - the lowest grade on the report card. I don't know if malaria will make a comeback in the US, but we had better pay attention to our flood control infrastructure - just in case.

America effectively waged an all-out, no-holds-barred war on wetlands during the first half of the 20th century. The environmental impacts of this campaign were considerable, however properly engineered levees and the associated drainage systems were instrumental in reducing flooding and making the land productive for agriculture and for general economic development.

Environmentally friendly flood control and drainage infrastructure is challenging, but it is possible. This needs to be a higher priority for agencies responsible for combating malaria.

Jeff Juel, PE
www.jueltide.com

William Jobin's picture
Submitted by William Jobin on

Thanks Jeff,

for reminding us of the importance of water management in economic development - and by the way, for its role in eliminating anopheline breeding grounds.

Just a question - to start. In your work in managing coastal wetlands, are you working in tropical areas where anophelines breed and are affected by salinity? Do you monitor salinity changes when you install your tide-gates? That seemed to have been a key effect of the anti-malaria coastal work that Schwellengrebel did in Indonesia.

Firstly, as you say, the US waged war on wetlands so effectively during its agricultural and urban development that we had to pass a Wetlands Protection Act to avoid elimination of all wetlands. The Act aimed at reducing the huge losses in wildlife habitat, especially for aquatic birds, animals and vegetation, without realizing the beneficial impact we got from the loss of anopheline breeding sites.

When I come back to the states I have sometimes worked for local Conservation Commissions in preventing developers from draining swamps. I found it ironic to realize that while working in Puerto Rico and Sudan I was guilty of the same drainage activities; something I cannot do here in Massachusetts!

Secondly, besides eliminating wetlands, urban development also contaminates the water, again destroying anopheline breeding sites. And the water contamination from US development was so bad that we had to pass a Clean Water Act. Furthermore, in many urban areas the exhaust fumes from vehicles are so bad the mosquitoes couldn't survive as adults either. So we had to pass a Clean Air Act.

This water and air contamination is already operating in Africa to limit malaria in urban areas. We found this out in Luanda, capitol of Angola, when asked to look at malaria problem in the city. A quick analysis of water and air contamination in the urban setting showed no anophelines, and epidemiological studies also showed no malaria. In the heart of Africa.

The other part to this story about changes in Mosquito Ecology is about changes in Human Ecology that economic development brings about - namely improved housing with screens, and electric fans.

It is ironic that these important ecological problems in developed countries are also probably the reason why anophelines have such a hard time there. Thus destruction of anopheline Mosquito Ecology by development might be an important aspect of moving from malaria suppression to the more stable malaria elimination which has been seen all over the developed world.

And the change in Human Ecology - where people are protected from biting anophelines - gives us the other link which explains why malaria does not re-establish, even when the vector or infected people move in.

So this offers us an answer to the question; How long do we have to suppress malaria? - until development destroys the mosquito ecology for anophelines and improves human ecology. Fortunately, it is becoming clear that suppression of malaria accelerates economic development in some countries, by increasing labor productivity.

From this, we should also be able to see a light at the end of the tunnel for Africa - an Exit Strategy.

Bill

William Jobin Director of Blue Nile Associates

Submitted by Ricardo Ataide on

Hi Bill,

I worked in Luanda from April to October of 2004 and was unlucky (stupid?) enough to get malaria there. I was working in the Cajueiros Hospital, in the Cazenga neighborhood and in the Kilamba Kiaxi Hospital. I certainly saw other patients there with malaria, although I cannot say if they caught it inside or outside Luanda. When did you conduct your study there? Was it part of the PMI study that was published in 2009 (i think)? Can anyone of the MW members from Angola comment on what is the current situation in Luanda?

Ricardo Ataíde

William Jobin's picture
Submitted by William Jobin on

Sorry Ric,

You certainly have reason to disagree with my broad statement about urban pollution controlling anophelines in Luanda. I based that on my month or so cruising along the main coastal areas of the city, near the airport, and especially in the coastal swamps around Cacuaco at the northern edge of the city, which the MOH thought was hot for malaria. We found no mosquitoes. But Luanda is a huge, sprawling and growing city. Perhaps there were some parks or undeveloped areas near your hospitals? Your Cajueiro and Kilamba Klaxi Hospitals were more in the middle of the city.

No, I had nothing to do with the PMI study you referred to. It was done later by Julie Thwing of CDC Atlanta in 2009 where she diagnosed high rates of false positivity (90%) in reports of Luanda hospitals and other health units using clinical diagnoses. So she concluded that the reports of malaria in Luanda were not to be respected.

I too would be eager to hear if any of our colleagues on this website know about conditions in Luanda. It is not a typical African city as it is overwhelmed with rich diamond, gold and oil tycoons. There are so many SUVs on the roads that it is faster to walk.

Bill

William Jobin Director of Blue Nile Associates

Submitted by Ricardo Ataide on

Hi Bill,

In reality malaria in Luanda is really not very prevalent. I recall a study which showed a 8% prevalence of malaria among people coming from outside of Luanda and only a 1% prevalence among those who never left the city. In one survey of malaria in pregnancy i think it was 10% or 11% of women (although I cant remember if they were from Luanda or from outside of Luanda...). I have no idea if there was ever a study looking at malaria by neighborhood... Like you say, Luanda is a city of enormous contrasts so what you find in one neighborhood is not necessarily what you find in the next. I would love to hear from people in Luanda about this. Lets wait!

Ricardo Ataíde

Jeff Juel's picture
Submitted by Jeff Juel on

Bill - Thank you for your thoughtful comments.

Within the past month, I've been developing a proposal for multiple 20 ft x 15 ft tide gates for a project in Malaysia. Other than that, all of my projects have been in the US and Canada.

I see three variables that can be manipulated to suppress / eliminate mosquito breeding in a drainage: 1) increased salinity; 2) moving water (ebbing and flooding with the tides); 3) the same high tide every day.

In many locations that adjoin bodies of water under tidal influence, there is no salinity. Fresh water - being less dense than salt water - ebbs and floods on top of a salt water wedge that moves upstream and downstream with the tides and the varying stream flow.

Your suggestion/observation that: "ecological problems in developed countries are probably the reason why anophelines have a hard time there" got me thinking... In America we're cleaning our rivers and streams and restoring wetlands. We're also neglecting our levees. Hmmmm...

Might we be setting the stage for a resurgence of mosquito-borne disease in the U.S. ?

If this happens, I am confident that Americans will not accept ITNs as a viable solution. (In my humble opinion, it's not fair for us to expect people in developing countries to embrace sleeping under ITNs as THE solution for their malaria. Especially in hot climates with no air conditioning.)

From what I've heard, some species/larvae can thrive in filthy water, and some can survive in fairly salty water. I think this indicates that mosquitoes will evolve and hang on as things change. The fraction of the population that is anopheles may shift as the conditions change - and that may be good, and it may be bad.

The regular flushing / dilution caused by my tide gates is something that mosquitoes will never evolve around - they need stagnant water. As an added bonus, the flushing dilutes contaminants and improves water quality for fishes, birds and wildlife. We can eliminate stagnant water (thus mosquito breeding) without wiping out wetlands.

What other vector control approaches are environmentally-friendly?

Keep up the good work and keep looking for the light at the end if the tunnel!

Jeff

Jeff Juel, PE
www.jueltide.com

Mark Featherstone's picture
Submitted by Mark Featherstone on

Very interesting article. Thank you so much. For someone who has experienced winter in Ottawa, it may be hard to imagine that malaria was once a problem there, but such was the case. For any who are interested, here's a useful link:

http://www.rideau-info.com/canal/history/locks/malaria.html

Mark

 

Mark Featherstone
School of Biological Sciences
Nanyang Technological University
Singapore