the border

Sometimes people ask me why I work on malaria in Thailand.  Most of the malaria in the world, most of the deaths from malaria in the world, occur in Africa.  So if I want to study malaria, why not study in Africa?  An honest answer would have to include the opportunities that happened to fall in place, but there are real substantive reasons to be very interested in malaria in Thailand.

What I actually study is what we sometimes call “border malaria” – a strange pattern where malaria clusters along international borders.  This is the pattern in Thailand, where malaria is almost completely absent in the central plains.

Probably the easiest way to think about these maps is: A. is where the falciparum malaria is, and B. is where it could be.  Maps from the Malaria Atlas Project: http://www.map.ox.ac.uk/

Understanding why this pattern occurs isn’t easy.

If you look at a elevation map of Western and Northwestern Thailand you’ll see that much of that border consists of mountains and hills.  You can't tell from this map, but those same areas are also heavily forested.  This aspect of the landscape has a whole lot to do with the persistence of malaria in this area.  It has a lot to do with ecology (both human and mosquito), politics, demography, economics, and a few other sociocultural factors.

These mountain areas aren’t heavily populated in the sense that Bangkok or Chiang Mai are, but they have been inhabited for a long time.  Along with the Thai who live in this area, most of the inhabitants consist of what are commonly called Hill Tribes.  These are groups of ethnic minorities who live, both literally and metaphorically, on the margins of Thai society.  They have different cultures, different languages, different houses, slightly different ways of making a living, and ultimately different health problems.

They also live in a vastly different ecology than does most of the rest of the country.  The farther away you get from big cities, the more the roads and other forms of infrastructure (including hospitals and clinics) crumble away.  In the wet season everything is soaking wet and the rivers spill over their edges while in the dry season it can be quite hot.  But it’s also a beautiful place, one of my favorite in the world.  I find both the landscape and the people to be awe-inspiring.  

My main study population here is the Karen.  Living along the international border, on the edges of both Thai and Burmese society, things have been quite difficult for the Karen for a long time.  They spent well over half a century at war with the Burmese military and the symptoms of this warfare are far reaching.  The Burmese military would sometimes attack Karen villages, rebel fighters, farmers, school children, monks and all – and villagers would flee across the border into the relative safety of Thailand.  Some set up makeshift refugee camps while others settled into official camps that have existed now for decades.  At times these camps, with huts built almost on top of each other and constructed of bamboo and dried heliconia leaves, would be set ablaze by the Burmese.  (Here is a nice publication about some of this history, from The Border Consortium).

Mae La camp, which is about 30 kilometers south of where I live, has around 50,000 people living in it, including some who are third generation camp inhabitants. Image from: http://en.wikipedia.org/wiki/Mae_La_refugee_camp     

Many things were lost during these years.  Don’t get me wrong, plenty of Karen remained resilient and strong throughout these hard times – they are a lively and outwardly happy people who love to sing and dance, but Karen elders and their knowledge were killed.  People lost limbs to the many land mines that litter this border region.  Some lost their sanity and others lost their hope.  Children lost their chances at education.  All of this for over half a century.  Seriously, imagine a society that hasn’t been able to settle down and focus on families and communities for over 50 years.  Perhaps the greatest loss in this time has been the cohesiveness of such social institutions.

Malaria has been a major cause of both death and sickness for the Karen throughout this time, but these types of conditions make it difficult to focus on a single problem or to even do anything about it.  As malaria researchers have found all over the world, when people have more pressing "for sure" problems (like needing to fill their bellies with food), it is hard for them to worry about invisible parasites in tiny mosquitoes.  Also, preventing malaria means that communities and households need to be working together for this goal.  Community members must work together to ensure people are educated about where the disease comes from and how to prevent it.  Standing water needs to be covered, villages should be well drained, people need to use mosquito nets and they need to seek treatment when they’re sick.  But these are all things that don’t happen when communities are frequently uprooted in the middle of the night only to be forced to move somewhere else, perhaps deeper into mosquito infested forests and hills, to get away from soldiers who wish them harm.  After having to do this several times, people are likely to give up on building permanent communities.  What’s the point when you’ll probably just have to move again one night?  

On the other hand, the Thai have been in a comparatively better position to handle the malaria problem and for most of the country that is exactly what they’ve done.  For most Thais, malaria is a concern of the past.  While I can’t speak for the Thais, I also think many feel as though their neighbors frequently weigh them down.  Thailand is more economically developed than its mainland neighbors (especially Cambodia, Myanmar, and Laos).  Many migrants from these economically poor regions come to Thailand seeking work.  The Burmese are their ancient enemies and while the Karen certainly aren’t the Burmese, they still come from across that border and use the resources (including health care) that are available in Thailand.  The situation is in some ways quite reminiscent of the Southwestern United States, complete with the ill-feelings that some have for the migrants that come across the Mexico border.  The malaria researchers who’ve worked here for a long period of time also have fresh memories of this border area as a dangerous place, where even elephants and water buffalo sometimes step on landmines that were buried years ago and where mortars inadvertently wind up sunk in neighbors front yards.

But money for malaria control and prevention flows into Thailand from lots of different sources (more on that in a future post).  Aid that is specifically geared toward these border populations, frequently channeled through the numerous NGOs in this area, also flows in from many parts of the world.  Yet while the problem almost certainly won’t be fixed in the absence of money, the money must be efficiently directed.  The money doesn’t always make it to the people that need it the most.  Very remote populations that are still on the Burmese side have long been neglected, if for no other reason than because they’re very difficult to reach.  More recently though, there are signs of peace (this is a big point of contention among the Karen!)  More foreigners are allowed into Myanmar/Burma and this means that medical teams have better access to some of these communities.  Even while this is occurring though, there are remote Karen populations on the Thai side that remain ignored.  When I first began working on malaria in Thailand, the story I heard was that most of it came from Burma via migrants.  While that does sometimes happen, it is increasingly obvious to me that small pockets of very high malaria transmission on the Thai side of the border remain.  It’s just that those communities with the most malaria seem to mostly be  non-Thais (for that matter, a lot of people in these areas have no official nationality at all).

And since political reforms have begun in Myanmar, and outside nations have been dropping their sanctions, funding for border related NGOs and other groups has been drying up (see here, here, and here, for example).  I suppose that it was only sexy to donate money when there was an active war going on.  I assure you that the war zone here on the border, and all of its implications, still exists today.  (To be fair, many people want to move their funds into Myanmar.  With that comes the likelihood that some of that money will go to the government.  In my opinion, it also means that many people on the Thai side are abandoned).

I admit that I've only worked on malaria in a few places, but I can't imagine a place in the world where malaria is more obviously linked to social, economic, and political factors.

Now, back to the question that I began this post with: Why do I study malaria here?  Aside from the fact that I just really love this part of the world – there is hope on the horizon and that hope keeps me going.  At one point I was a starry eyed anthropology student who wanted to do something about infectious diseases.  I went to where some of those infectious diseases were, began working with other people in public health (not just Thais), and I found out that not everyone was as passionate as I.  In fact, public health work is a job.  Those malaria funds that flood into this part of Thailand create jobs for people, and some of those people aren’t necessarily concerned about malaria control, prevention, or eradication - some of them just want a job.  And I think this gets at a deeper, more troubling problem that must exist anywhere where there are people who work with health problems.  If you are completely effective, if you actually get rid of a disease, you've actually worked yourself out of a job...

But malaria incidence in Thailand has decreased dramatically since the 1960s and it may even be going down in parts of Burma/Myanmar.  Political changes in Burma/Myanmar mean that there is much less fighting, in this region anyway, than there has been for a very long time.  The resources are here, even if I don’t think they’re always directed in the most efficient way.  I think that many of the young Karen adults are now in a place to learn new skills, take leadership roles, and to gain back much of what they’ve had to do without for so long.  The implication of these things, in particular the latter, I think is that we will see very real changes in the overall health and well-being of the Karen in the very near future.  I’d love to be a part of that.

How to turn the interesting into the stupid: a magnetic field sensing gene?

How migrating and other species navigate or orient themselves in the world is a fascinating subject.  There are all sorts of potential cues that birds, fish, bees, and butterflies might use.  They include the elevation or declination of the sun, odors, scent imprinted or visually memorized trails, visual monitoring of celestial position (stars, moon, etc.), and gravity.  And there have long been studies and speculations about whether gravitational navigation using magnetic signals might explain some migratory patterns.

Interesting work is reported in a NY Times story about this.

Many animals rely on the magnetic field for navigation, and researchers have often wondered if people, too, might be able to detect the field; that might explain how Polynesian navigators can make 3,000-mile journeys under starless skies. But after years of inconclusive experiments, interest in people’s possible magnetic sense has waned.

That may change after an experiment being reported last week by Steven M. Reppert, a neurobiologist at the University of Massachusetts Medical School, and his colleagues Lauren E. Foley and Robert J. Gegear. They have been studying cryptochromes, light-sensitive proteins that help regulate the daily rhythm of the body’s cells, and how they help set the sun compass by which monarchs navigate.

Because the DNA sequence of one of the butterfly's cryptochrome genes is similar to that of a human gene (CRY), they transplanted the human gene into fruitflies and report their results.

[W]e show using a transgenic approach, that human CRY can function as a magnetosensor in the magnetoreception system of Drosophila and that it does so in a light-dependent manner. Thus, human CRY has the molecular capability to function as a light-sensitive magnetosensor, and this finding may lead to a renewed interest in human magnetoreception. 

Whether it does or not, however, is still under contention.  But as is so typical, the authors and reporter BS-up their story with claims that this may explain how humans find their way.  For example (of course), how those Polynesian sailors did it (we think that has clearly been demonstrated in terms of celestial navigation, and isn't a real question any more, but maybe we've misremembered).  

But it is simply preposterous, we think, to give this the usual hyperbolic spin.  Humans move too slowly for much of this to make sense, even if the gene does code for a useful magnetosensor.  As with any other 'chaos' formation, if our direction is even slightly off, then we'd be wildly off over any distance--as off as if we had no magnetic sense.  Going very long distances would not be practical with this sense and we know from centuries of direct evidence that sailors got lost and drowned because without real instruments (even with the stars available) it wasn't possible. No fitness advantage there, til the astrolabe-gene came along.  Did the magneto-gene evolve in a very non-Darwinian way, millions of years ago, to lay in waiting til the Age of Sail?

Our own personal (lack of) sense of direction (one of us could get lost just going out to pick up the paper) is also clear proof of the Bollocks Principle: don't believe what you read about science without first thinking seriously about it.

How long would it take to walk to the ends of the Earth?

"Who started walking out of Africa? Not everybody walked. Very few people walked, and they walked to the ends of the Earth. The geneticists now have found that the people who migrated had a particular gene, and this gene makes you a risk-taker, a wanderer. Bipolarity is an extreme version of this gene, and the people who migrated, they had this gene."

This is a quote from Indian political economist, Deepak Lal, on the BBC radio show, The Forum, which aired 05/24/09. Lal went on to say that the people who inherited this gene for risk-taking are now ethnic minorities, which explains why they tend to "punch above their weight".

But the people who migrated out of Africa are ancestors of us all. If they had a gene 'for' risk-taking, all of us would have it, not just today's ethnic minorities. And, it can't be argued that for genetic reasons ethnic minorities tend to succeed more often than majority populations because the minorities are or were majorities somewhere at some time.

It's amazing how misguided smart people can be about genetics and population history. Granted Lal is an economist, not a population geneticist or anthropologist-- but he spoke so authoritatively! Darwinian scenarios, of the BS as well as plausible variety, are so easy to put forth with an air of confidence! But, is this all air, or does it actually matter when people get it so wrong? We suggest that it does for a number of reasons because it happens in many contexts, with ramifications, not just on BBC radio programmes.

First, the idea of a gene 'for' risk-taking has been reported, but the original study has been difficult to replicate, in part because it's difficult to define risk-taking, and in part because genes 'for' behavior have been quite elusive. Populations considered to be high risk-takers or violent by some, with a high frequency of the DRD4 mutations originally associated with risk-taking, might be considered to be pacific by others, for example. So, this trait is, like most complex traits, difficult to define and genes 'for' it difficult to confirm. If one thinks about genetic mechanisms, many genes would contribute to such traits, and they would be very culture-specific or their manifestation would be, at least.

Second, genes 'for' bipolarity, again as for all complex traits, have not been confirmed. Mapping genes making major contributions to psychiatric disorders has been very problematic, at best. Some candidates have been found, but even they generally account for only a small fraction of the instances.

Third, ethnic minorities are only such at certain times and places.

Fourth, can we really conclude that ethnic minorities are all feisty? It's funny how people with guns, money, or power can seem so much more adventurous than those who haven't the same assets.

These simple (or is it simplistic?) Darwinian arguments reflect incredibly naive population biology. Basically, nobody 'walked out of Africa' in the alleged sense. People did not have travel posters or travel agents. They might go upstream or 'over there' to find game or plants they liked to eat. If nobody was living there (or only brute Homo erectines), they might decide to kick them out and take over a nice campsite. Nobody ever heard of the ends of the earth! They did not know there were island paradises in the Pacific to go vacation at.

Young adults would pair up and move to better pastures, perhaps to get away from their annoying parents or pests in their little hunter-gatherer bands. They would, however, generally stay in touch--not go too far, because family was everything for social survival (and mates in the next generation). Gradual expansion would be on foot and in a sense by everyone, going over the next hill for open territory. Nobody would know they were going anywhere!

Each generation, village exogamy (kin-based mating rules) would mean that the 'explorers'' children would have to return to their former hearth and home to find mates. There would be large amounts of inter-village gene flow, back and forth, each generation.

It is possible that among those who chose to pop over the hill, those more inclined would have some slightly increased probability of doing that. But in the overall scheme of things, genetic drift and other kinds of chance would have watered down any such signal.

The genetic data clearly show that the farther from Africa people are, the smaller the subset of 'African' genetic variants they carry. This does not mean that they purified African adventure genes, and those in Tierra del Fuego aren't pure adventurers, nor less so than the Bantu marauders who captured each other in wars and sold the victims into slavery (unless there is an adventure gene in the slaves that made them turn themselves in?)

In historic times, and in invasions, hordes of armies or boatloads of pilgrims were forced to travel and settle elsewhere, in large numbers. They were not selected based on Indiana Jones genes.

We'll be a lot better off in evolutionary reconstructions, especially as regards behavior which clearly reflects social biases of the authors, if we temper our view based on a realistic understanding of the demographic chaos that is life!