Archive | April 2014

Did pathogens influence the course of human development?

Roman toilets

Roman toilets

I would say “it depends.” I was just reading an interesting article on the “pathogen stress theory” of the development of human societies, most often attributed to Randy Thornhill, an evolutionary biologist at the University of New Mexico.

According to the “pathogen stress theory of values,” the evolutionary case that Thornhill and his colleagues have put forward, our behavioral immune systems—our group responses to local disease threats—play a decisive role in shaping our various political systems, religions, and shared moral views.

If they are right, Thornhill and his colleagues may be on their way to unlocking some of the most stubborn mysteries of human behavior. Their theory may help explain why authoritarian governments tend to persist in certain latitudes while democracies rise in others; why some cultures are xenophobic and others are relatively open to strangers; why certain peoples value equality and individuality while others prize hierarchical structures and strict adherence to tradition. What’s more, their work may offer a clear insight into how societies change.

This is a reasonable view, and something I’ve long observed from working on infectious diseases in developing countries. The developmental trajectory of a country is influenced by the deliberate avoidance of illness. An example can be seen in the locations of African cities. Many African administrative capitals are located on isolated, cool hilltops, far away from rivers and lakes. Colonialists would intentionally set up shop in areas where they were unlikely to encounter malaria.

Developmentally, this has had major implications for trade within Africa. European cities are often placed along water ways amenable to domestic European trade. The lack of trade between African countries is one of the reasons the continent has developed so poorly. This is the direct result of not only colonial priorities of resource extraction to Europe, but also the unfortunate placement of economic centers in response to malaria.

Certainly, the nature of cities themselves have much to do with the control of infectious diseases. Public works often involve the management of sewage waste and the delivery of clean water. Thornhill might suggest that the development of democracy, citizen involvement and taxation to pay for urban improvements are in direct response to enteric diseases.

However, while it is interesting to try to apply this view, it can be taken to the extreme:

Fincher (a graduate student of Thornhill) suspected that many behaviors in collectivist cultures might be masks for behavioral immune responses. To take one key example, collectivist cultures tend to be both more xenophobic and more ethnocentric than individualist cultures. Keeping strangers away might be a valuable defense against foreign pathogens, Fincher thought. And a strong preference for in-group mating might help maintain a community’s hereditary immunities to local disease strains. To test his hypothesis, Fincher set out to see whether places with heavier disease loads also tended toward these sorts of collectivist values.

I’m not sure it’s that easy to boil down political differences between Asia and Europe to a need to manage infectious disease. Certainly, Sweden is more collectivist than England, but I wouldn’t say that their infectious disease profiles are all that different.

Worse yet, if taken to the extreme, this “hunt for significance” will provide one with evidence to support any crazy theory at all. Pathogens exist wherever humans do. Moreover, we risk attributing the contribution of pathogens to human development based on current conditions, assuming that the present is deterministically preordained centuries ago. Until very recently, nearly the entire world was at risk for malaria, but despite this, various societies have embarked on different social and political trajectories.

The biggest problem I have with the theory is in its basic in rational theory. It assumes that humans are making rational choices based on pathogen threats, when we know, and particularly those of us who work in the tropics, that humans often have poor conceptions of disease transmission and causes of illness. At times, despite very obvious threate, humans will act in manners which exacerbate that threat. The history of enteric disease is filled with tales of ignorance and folly.

If we are going to subscribe to a rational model of political and social development which includes pathogens, then we have to also address first, the ability of pathogens to hijack human behavior to create new opportunities for replication and survival and second, that social changes can exacerbate the worst effects of infection. For the first point, I would look to the development of international trade systems which allow pathogens such as influenza to move around the world quickly, increasing opportunities for mutation to avoid immune responses. For the second I would point to polio, a disease which becomes a problem on after the introduction of water sanitation practices.

Thornhill’s ideas are interesting, and certainly provide good material for the popular press and BBQ conversation, but they require that the reader suspend too much consideration of the details of the complex history of human social and political development. Taken with restraint, as in the example of the locations of African cities, they can provide interesting insights into how current conditions are impacted by past pathogenic threats.

I like to think that we are doing better now…..

Every once in a while, you run across something that just gives you the chills.

“A report presented to the World Health Organization (WHO) in 1948 states: “It is not enough to quote that about 3,000,000 deaths are caused yearly by malaria in the world, or that every year about 300,000,000 cases of malaria occur …… that malaria is prevalent in tropical and subtropical areas where food production and agricultural resources are potentially very high, and that, by affecting the mass of rural workers, it decreases their vitality and reduces their working capacity and thus hampers the exploitation of the natural resources of the country. At a time when the world is poor, it seems that control of malaria should be the first aim to achieve in order to increase agricultural output” (WHO, 1948).

Snow RW, Amratia P, Kabaria CW, Noor AM, Marsh K: The changing limits and incidence of malaria in Africa: 1939-2009. Adv Parasitol 2012, 78:169-262.

Today is World Health Day!

dengueToday, April 7th. is World Health Day, an annual event sponsored by the World Health Organization to help bring attention to pressing public health issues.

This years event focuses on vector borne diseases like dengue fever and Chagas disease, which are transmitted through a third party host such as Aedes mosquitoes or triatomines (kissing bugs).

Both of these diseases are becoming increasingly relevant as the world urbanizes. Dengue and malaria form a complementary nexus of diseases. Malaria is largely associated with rural areas, and rarely found in cities, where dengue fever is almost exclusively found in urban areas. Generally speaking, dengue is a disease of development, where malaria is a disease of the lack of development.

While known to be distributed widely through Latin America and Southeast Asia, dengue has yet to make it on Africa’s radar yet, simply (in my opinion) because not enough people are looking hard enough. Africa, as the most rapidly urbanizing area of the world will eventually face a double burden of dengue and malaria and health facilities aren’t yet prepared to deal with it.

A network visualization of international migration

The UN keeps data on migrations patterns around the world, tracking origin and destination countries and number of migrants (Trends in International Migrant Stock: Migrants by Destination and Origin). I took some time out and created this network visualization of origin and destination countries from 2010. Other years were available, but this is all I had time for.

The size of each node represents the number of countries from which migrants arrive. By far, the most connected country is the United States, accepting more people from more countries than any other place on the planet. Most areas of the network represent geographic regions. Note that Africa is clustered at the top, and pacific island countries are clustered at the bottom.

An interesting result is that countries tend to send migrants to other countries which are only slightly better off than they are. For example, Malawi sends most of its migrants to Zambia and Mozambique, and Zambians go to South Africa, whereas those countries do not reciprocate to countries poorer than them. Wealthy countries tend to be more cosmopolitan in their acceptance of migrants.

Click on the picture to explore a larger version of the graphic.


Keiji Haino at MOCAD, Detroit

DSC_1682I went and checked out Nazoranai, Keiji Haino’s unit with Steve O’Malley from SUNN and Oren Ambarchi from Australia.


I’ve known of Haino’s work since the early 90’s. Haino is an odd figure, blending Blue Cheer with Albert Ayler and infusing it with butou dance and Japanese minstrelism (a word I just made up). Somewhere along the line, I lost track of Haino’s work, particularly while living in Japan where he barely registers. In Osaka, you wouldn’t even know he existed. He told me he only plays there twice a year.

Fortunately, I got a translating gig for him so I was able to spend a little time talking with the man. Turns out, he’s a really funny guy. We talked at length about guitars, pizza, how young people in Japan are on the road to hell and the challenges of being in cities after living in the country for a long time.

I had forgotten what a major influence Haino has been on my musical life. I started using multiple amplifiers and didn’t shy away from the guitar because of Haino. Despite the amplified guitar’s somewhat pedestrian roots, Haino wields it like a fine sword, taking advantage of both the amplifiers and the room itself. It can be said that the entire room is Haino’s instrument. Though I’ve mostly given up playing (just don’t have the time) and wasn’t ever very good at all, I was incredibly moved to finally see one of my heroes play.

Haino was incredibly particular about everything. The lights had to be at a certain brightness and a certain color, and the audience was required to stand at a particular distance from the stage “for their own safety.” Though he was quite jovial about his specific requests, once the show started, it made sense why things had to be laid out in a certain way.

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