Category Archives: medical anthropology

War as a Driver in Tuberculosis Evolution

by Michelle Ziegler

Russia has been all over the news lately. Beyond our recent election, increased Russian activity on the world stage has public health consequences for Europe and farther afield. It has been known for a long time that post-Soviet Russia had and continues to have serious public health problems. One of their particular problems that they have shared with the world is their alarmingly high rate of antibiotic resistant tuberculosis. There is no mystery over the root cause of their antibiotic resistance woes — poor antibiotic stewardship (Garrett, 2000; Bernard et al 2013).

A study by Vegard Eldholm and colleagues that came out this fall sheds light on the origins of particularly virulent tuberculosis strains with high rates of antibiotic resistance that recently entered Europe.  A large outbreak among Afghan refugees and Norwegians in Oslo, Norway, provided a core set of 26 specimens for this study that could be compared with results generated elsewhere in Europe (Eldholm et al, 2010). The Oslo outbreak clearly fits within the Russian clade A group that is concentrated to the east of the Volga River in countries of the former Soviet Union. They name this cluster the Central Asian Clade, noting that it co-localizes with region of origin of migrants carrying the MDR strains of tuberculosis reported in Europe.

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Figure 5. Phylogeny of the Afghan Strain Family (ASF). Colored boxes represent the country of origin: Afghanistan is orange; other countries are gray. (Eldholm et al, 2016)

When the Oslo samples are added to the family tree, phylogeny, of recent tuberculosis isolates from elsewhere in Europe a distinctive pattern emerges. The branches on the family tree are short and dense, suggesting that this is recent diversity, that they calculate to have occurred within approximately the last twenty years (Eldholm et al, 2016).

The Central Asian Clade spread into Afghanistan before drug resistance began to develop, probably during the Soviet-Afghan war (1979-1989) producing the Afghan Strain Diversity clade. Slightly later, the Central Asian Clade still in the former Soviet states begins to accumulate antibiotic resistance as the public health infrastructure crumbles in the wake of the dissolution of the USSR. The invasion of Afghanistan by the US and its allies in 2002 toppled the Afghan state, crippling infrastructure and spurring refugee movements within and out of Afghanistan. The lack of modern public health standards in Afghanistan since their war with the introduction of these strains by the Soviets in the 1980s provided fertile ground for the establishment and diversity of tuberculosis in the country. Instability has been pervasive throughout the entire region sending refugees and economic migrants from both Afghanistan and the former Soviet states into Europe.

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Movements of the Central Asian Clade (CAC) since c. 1960 and the subsequent Afghan Strain Family (ASF). (Eldholm et al, 2016)

Their dating of the last common ancestor for the Central Asian Clade to c. 1961 is significantly younger than the previous dating of 4,415 years before present for the Russian clade A (CC1) of the Beijing lineage of Mycobacteria tuberculosis. They account for this difference by noting differences in their methods of assessing sequence differences and note that their method is in line with other recent evolutionary rates for other tuberculosis clades.  The diagnosis dates and length of the arms on their reconstructed phylogeny suggests that there were multiple, independent introductions of the cases from Afghanistan and the former Soviet republics. This is consistent with a repeated periods of refugee movements from central Asia into Europe.

The rapid proliferation and diversification of the Afghan Strain Family may be explained by a known syndemic between tuberculosis and war (Ostrach & Singer, 2013). Conditions of war everywhere disrupt food systems, destroy critical infrastructures such as electricity and water systems, interrupts medical supplies, and the human public health infrastructure of the country. Malnutrition and stress are known contributors to immune suppression. Many pathogens flourish simultaneously in these conditions increasing the infectious challenges the population must fend off. Diarrheal diseases are the most acute and demanding of rapid attention, allowing longer-term diseases like tuberculosis to slip through the overburdened healthcare system. Afghanistan has experienced nearly forty years of war, political instability, and repeated infrastructure destruction. Thus, they were primed for both the establishment of new tuberculosis strains during the Afghan-Soviet war in the 1980s along with the proliferation and diversification of tuberculosis during the Afghan-American war of the last sixteen years.

Established syndemics between tuberculosis and war have been made retrospectively following the Vietnam war and the Persian Gulf war of 1991 (Ostrach & Singer, 2013). In Vietnam, prolonged malnutrition caused an eruption of tuberculosis along with malaria, leprosy, typhoid, cholera, plague, and parasitic diseases.  A WHO survey in 1976 found that Vietnam had twice the incidence of tuberculosis over all of its neighboring countries (Ostrach & Singer, 2013). When the military intentionally targets water infrastructure as it did in Vietnam and Iraq, the production of civilian infectious disease is a tactic of war. In both Vietnam and post-Gulf war Iraq, more civilians died of malnutrition and infectious disease than enemy soldiers died of all causes (Ostrach & Singler, 2013).

It seems likely that this is just one of the first studies to establish a link between serious infectious disease developments and the Afghan wars. The current war zones throughout central Asia and the Middle East already have ramifications for the public health of the entire world that walls along borders will not be able to stop. Most of the cases in the Oslo outbreak were Norwegians, not Afghan immigrants. Diseases will spread beyond the migrants so country of origin screening will be of little use before long.


Reference

Eldholm, V., Pettersson, J. H. O., Brynildsrud, O. B., Kitchen, A., Rasmussen, E. M., Lillebaek, T., et al. (2016). Armed conflict and population displacement as drivers of the evolution and dispersal of Mycobacterium tuberculosis. Proceedings of the National Academy of Sciences of the United States of America, 201611283–16. http://doi.org/10.1073/pnas.1611283113

Ostrach, B., & Singer, M. C. (2013). Syndemics of War: Malnutrition-Infectious Disease Interactions and the Unintended Health Consequences of Intentional War Policies. Annals of Anthropological Practice, 36(2), 257–273. http://doi.org/10.1111/napa.12003

Bernard, C., Brossier, F., Sougakoff, W., Veziris, N., Frechet-Jachym, M., Metivier, N., et al. (2013). A surge of MDR and XDR tuberculosis in France among patients born in the Former Soviet Union. Euro Surveillance: Bulletin Européen Sur Les Maladies Transmissibles = European Communicable Disease Bulletin, 18(33), 20555.

Beyond Germs: Native Depopulation in North America

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Beyond Germs: Native Depopulation in North America. Edited by Catherine Cameron, Paul Kelton and Alan Swedlund. University of Arizona Press, 2015.


With the number of emerging infectious diseases climbing and new revelations about plague’s past, this book is a timely caution to the rhetoric surrounding so-called virgin soil epidemics. This book is the publication of an interdisciplinary conference held to discuss the causes of Native American depopulation hosted by the Amerind Foundation. Essays by David Jones, George Milner, Clark Spenser Larsen, Debra Martin, Gerardo Gutiérrez, Alan Swedlund, Catherine Cameron, Paul Kelton, Katheleen Hull, and James Brooks are included. Most of these essays are case studies in depopulation of specific areas.

David Jones opens the book with a discussion of the rhetoric surrounding so-called virgin soil epidemics that are credited with being the primary cause of native depopulation. Admitting the influence of his mentor evolutionary biologist Stephan J Gould, Jones favors social and contingent causes for depopulation over biological determinism. Perhaps the influential role that Gould played in my own formation as a biologist makes me sympathetic to Jones’ argument, but I can certainly live with that. Genetic determinism, in my opinion, is the easy way out to explain what can not be yet understood. His argument against the sweeping rhetoric of ‘virgin soil epidemics’ is, I think, very effective.

Milner’s chapter tackles the tricky problem of the pre-contact population collapse of the Mississippian culture centered at the mid-continent site of Cahokia, near St. Louis. This had been the largest and most (archaeologically) complex native culture in North America but it collapsed so entirely that the mid-continent was still sparsely populated when Europeans arrived a couple of centuries later. Medieval Cahokia had been more populous than  contemporary London. The example of Cahokia must give us pause for assuming that unrecorded demographic collapses that lack signs of massive destruction must be due to epidemics.

Larsen, Martin, Gutiérrez, and Hull cover the effect of the Spanish mission system in Florida, the Pueblo of the Southwest,  Mexico, and California respectively. Structural violence was seen throughout the Spanish mission system from hard, forced labor. Larsen discusses the changed how changed landscapes and lifestyles make natives more susceptible to infection. He sees a dramatic rise in cribra orbitalis/porotic hyperostosis as a sign of iron deficiency when it may actually be malaria. Wet Florida would have been susceptible to endemic malaria and a reservoir for it to spread through the southeast. Martin looks at the bioarchaeological evidence for a ‘creeping genocide’ in the peublos of the south west. Sporatic massacres of pueblo communities was used to enforce compliance by the wider culture. Cultural resilience was also stressed to the breaking point by a prolonged period of drought and environmental deterioration in the southwest that left them with marginal nutritional sufficiency. In this stressed environment, smallpox spread widely among the pueblo communities. Epidemics were part of a set of practices used to destroy or reorient native culture to make it acceptible, and more importantly controllable for the Spanish. Gutiérrez focuses on the methods and effects of identity erasure on demographics. The caste system that developed was very systematic “virtuous cycle”  with the goal of eliminating native identiy and indeed native (and African) ‘blood’ while maximizing Spanish identity and ‘blood’.

Chapters by Swedlund,  Cameron, and Kelton  examine tribes that dealt more closely with the English colonies and early American states. Swedlund looks at the great smallpox epidemic of 1633-34 beyond coastal New England up into the Connecticutt River valley. Cameron reviews the demographic effects of warfare and captive taking had on the Southeast, the northern Pays d’en Haunt (Great Lakes region), and the Southwest tribes. Colonial politics and trade caused more intertribal warfare than warfare directly with European colonists. Kelton writes about the disastrous experiences of the Cherokee with warfare, famine, and disease during the American Revolutionary War.

On of the overarching problems is the difficulty in determining population size before contact and then for the first couple centuries of the colonial period. Problematically, in the past abandoned villages have been assumed to be extinct due to disease rather than simply relocation or the movement of refugees to other tribes. The reality is that many areas that are fertile with Old World methods and domestic livestock were very difficult to make productive with native resources.

Over arching themes that I noticed which point toward other factors than just “germs” causing depopulation:

  1.  Use of starvation as an intentional weapon accomplished by burning fields and disrupting the agricultural cycle.
  2. Selective taking of women of reproductive age as captives/slaves causing a gender imbalance that prevented populations from rebounding.
  3. Selling captives to slavers rather than incorporating them into the tribe as pre-contact tribes often did to bolster their numbers and replace their dead. Sales were often to repay debts for European trade goods, especially weapons and ammunition.
  4.  Use of tribes as proxy militias by European powers to create intertribal warfare and recruitment of tribes by the British during the American revolution and war of 1812. Set up an adversarial relationship with the young American nation.
 In effect, I think the process they are all searching for is a syndemic that combined epidemics, nutritional deficiencies, systemic violence, slavery, and forced assimilation. Unfortunately they didn’t really consult the syndemic literature.

One of the things I took away from this collection is an appreciation for how long it takes to develop a fully agricultural culture. Many Native American groups were still in transition. Lacking domestic animals other than the dog, they were very vulnerable to climate and social disorder disrupting their agricultural cycle and yield. Some tribes adopted domestic animals from Europeans quickly. Colonists were greatly alarmed at how quickly the Cherokee adopted raising hogs and European crops, bringing them nutritional stability. Of course, horses are were adopted so well by natives that its hard for many of us today to even think of Native Americans without them.  The idea that domestic animals were worth the effort may have been what was missing most, rather than a lack of animals capable of being domesticated.

I highly recommend this book for anyone interested the dynamics of depopulation, “dark ages”, and most importantly for comparison to other “virgin soil” epidemic situations. I don’t think it’s a coincidence that other renowned virgin soil epidemics like the first and second plague pandemics occurred in times of ecological and social stress in addition to the epidemic in question. By opening the explanations for Native American depopulation up to other causes than disease,  it also opens up views into colonial life that even contemporaries tried to ignore. Wether their demise to disease was believed by contemporaries to be divine will or by modern historians as biological determinism, it has diverted attention away from the very human causes of depopulation and in some cases genocide.

CFP: Medieval Landscapes of Disease (Extended)

Call for Papers
Medieval Landscapes of Disease
International Congress of Medieval Studies
Kalamazoo, MI  May 12-15, 2016

Following on a successful session last year, I’m offering another session on Medieval Landscapes of Disease this year at Kalamazoo.

In recognition that diseases are manifestations of their environment, this session seeks papers that place medieval diseases within their environmental context. Just as a seed must be placed in good soil to grow, infectious disease requires a permissive environment to develop into an epidemic (or epizootic) and an ideal environment to bloom into a pandemic or panzootic.  I am open to all manner of studies and disciplines that address these issues.

Examples of acceptable topics:
  • Historic impacts of  epidemics and/or epizootics
  • Endemic disease in medieval environments
  • Environmental causes of disease such as malnutrition or industrial pollution related disease
  • Health effects of human-animal interactions
  • Applications of the One Health Approach to medieval disease
  • Archaeological assessments of human health and disease
  • Landscape alterations intended to improve human or animal health
  • Ecology of the built environment

Abstracts of no more than 300 words and the Participant Information Form should be sent to Michelle Ziegler at ZieglerM@slu.edu by September 15.  Deadline extended to Friday September 18. Pre-submission queries are welcome.

The Participant Information Form and additional information be found at  http://www.wmich.edu/medieval/congress/submissions/index.html .