Monday, December 10, 2012

Adding the human context to disease ecology

Sometimes there exist subregions where, for a variety of reasons, diseases just tend to lurk and persist regardless of what is occurring in the surrounding regions.  An excellent example can be seen in Southeast Asia, where there exists malarious pockets surrounded by malaria free regions.  In Southeast Asia, these places tend to be hilly, forested regions and international borders.  For example, both Thailand and China have been relatively successful at eradicating malaria from much of their nations while continuing to have a malaria problem along their borders with Myanmar (also known as Burma).

So what is it about these places that make malaria eradication so difficult, at least on the China or Thai sides of the border?  Well, the simple answer is that it’s complicated.

This last summer I made a trip to the border between China and Myanmar to visit one of the field sites we are using in our malaria research.  My trip to Nabang, China began in Kunming (the capital of Yunnan Province), where I caught a plane to Tengchong and then caught a five hour ride through steep mountains to the relatively small border town called Nabang.

Directly across the China-Myanmar border from Nabang is a town called Laiza which at one point was a tourist attraction for wealthy Chinese, offering a legal gambling outlet.  Today the fancy new gambling halls are still up and running in Laiza and there are several relatively nice hotels in Nabang, both mostly empty and waiting for the tourists to come.  Lining the streets of much of Nabang are brand new, fancy looking street lights, none of which have ever been turned on.  Nabang has the feel of a Wild West gold mining town after the gold is all gone.

So what happened to this place?  Basically, war happened.

Downtown Nabang, with Laiza in the distance.
Laiza, which is in Kachin state, is named after the indigenous group (the Kachin) that has historically lived in this region of Northern Myanmar.  The Kachin are known for their fighting skill, they were our allies in this region during WWII, and they have historically been at odds with the ruling national government.  In 2011, after a 17 year truce, civil war broke out between the Kachin and the government military.  Unless you’re familiar with this region though, you’ve probably never heard of this war.  This isn’t the type of shock and awe war that we all saw when the U.S. went to war with Iraq or even the high-level shelling currently occurring in Syria.  Villages get burned in the middle of the night, women and children are kidnapped, raped and forced into labor, and military camps are occasionally ambushed.  It is a low grade, slow-and-steady war that claws at the psyche of the people living in this area.   

The KIA (Kachin Independence Army) is currently located in the Laiza Hotel, right in the middle of what was once a tourist retreat.  

What does this mean for the human ecology of the place?  
For one, it means that many people are clustering up near the border in make-shift camps for ‘internally displaced persons’ (what you’re called when you’re a refugee in your own nation).  When I was there, the people living in camps were working together in preparation for many more people to arrive.  

Villagers preparing for new people to arrive.
It also means that the population has a very unique composition, made up mostly of women, children, and the elderly.  Working aged men were mostly absent, except for the occasional young adults that would zip by on their motor bikes, donning camouflage and carrying AK47s.  Instead of helping out with household chores and working in the near-by agricultural fields, the men are moving covertly through the mountainous and forested landscape, engaged in warfare with the Burmese military.    

A KIA soldier riding through town.
And what does this mean for the disease ecology of the place?
By disrupting the everyday lives of populations, conditions are primed for disease.  Close-quarters mean that easily transmittable diseases will almost certainly move through the population rather than be confined to individual households.  Diarrheal diseases that are common in children may become a problem for everyone.  The same is true for airborne diseases such as influenza and tuberculosis.  For already stressed and sometimes malnourished people, this is an added threat.

Furthermore, vector borne diseases are an increased threat.  Newly cleared fields easily form water puddles when it rains, making excellent breeding grounds for mosquitoes.  Dengue fever could easily thrive in these camps.  And for a variety of reasons, malaria is already a growing problem.  

Some preliminary research in this area has indicated that working-aged males appear to disproportionately acquire falciparum malaria infections.  Given that most of these working aged males are living in the conditions of war, moving through the jungles at night, sleeping out-doors, and almost constantly being exposed to a range of mosquito vectors, perhaps this is no surprise.  

And what happens when they are too sick to fight?  One could imagine that they then come home, with a thriving population of parasites swimming in their blood.  A potential real danger, and one that my research is particularly aimed at, is that these individuals could then pass the disease on to their families and neighbors. 

Also, given that artemisinins have been available in Myanmar and China for decades, and since there clearly is no regulation of their use in Myanmar (especially in this part of the nation), conditions are also primed for drug-resistant parasites.  We are already seeing this on the Thai-Myanmar border, it isn’t a stretch to expect to find it in this region next.  

And if these pretty terrible conditions weren’t bad enough, there is another disease that has predominated in this area for some time.  It is a hotspot for HIV/AIDS –because there are thriving sex and opium trades.  (Note: The sex and opium trade bring in problems of their own, even outside of infectious disease.)  Much of the world has been privy to the knowledge about where HIV/AIDS comes from, how it is spread, and how to keep from becoming infected.  However, Myanmar has been largely closed to the world until the last several years, meaning that such educational campaigns are unlikely to have reached many outside of the wealthy, urban, or elite of this nation.   

What does this all of this mean for public health efforts?  
Clearly this isn’t an easy place to work.  It isn’t even an easy place to get to.  Our collaborators at Kunming Medical University have sent several teams of graduate students to the field sites here in order to collect demographic and epidemiological data.  Many of them don’t stay for long.  It is a depressing environment, there are frequent earthquakes, the heat is almost unbearable and AC units don’t work when the electricity is out.  Oh… and it’s a war zone.   This makes getting data difficult, and given the fluctuating population size and composition, it makes epidemiological modeling difficult.  This means it is really hard to fully understand the disease situation.  

The hospital in Nabang, China has been badly damaged by earthquakes.  Here it is being repaired and expanded.  This hospital sees a lot of malaria cases as well as wounded soldiers from the fighting.
Not all malaria endemic places in Southeast Asia are the same but there certainly are some commonalities.  Another malaria endemic border zone, along the Thai-Myanmar border, was until very recently also a site of ethnic tensions and occasional war.  The Thai-Cambodian border zone was a strong-hold for the Khmer Rouge up until the 1990s.  It was also a site of heavy, informal mining efforts, which led to living conditions that appeared very similar to the refugee camps I’ve seen in Northern Myanmar on the Chinese border.  Perhaps a common theme across these regions is the disruption of ‘normal’ human ecology.  These are places where people haven’t had the chance to settle in, to develop their homes and villages, and to fix problems associated with sanitation and hygiene.  

Perhaps it is too much to think that some of these regions will ever be malaria free.  But I can’t help but think that conditions would be much more controllable, perhaps even with a low, maximally acceptable, background level of malaria, if only the socio-economic and political conditions weren’t as they are.  And while it’s easy for me to say that if we could just stop warfare and fix poverty that we’d have a lot more success at controlling disease, clearly doing these things isn’t anywhere near easy.  However, these challenges can’t even begin to be approached until there is a widespread realization that these are in fact the underlying, downstream conditions that lead to bad human health outcomes.  

Main road through one of the study villages near Laiza, Myanmar.  

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