This will be the first in a series of posts looking at the technical and practical aspects of studying ancient pathogens, or paleomicrobiology. First let’s look at why its worth spending time, money and a lot of creativity on old germs.
There are many reasons why directly studying ancient microbes is worthwhile. From a historical point of view, I think to understand earlier populations you have to understand what pathogens they coped with. What were their common bothersome infections and fearsome epidemics? Hearing a historian stay it doesn’t really matter what the agent of an ancient or medieval epidemic was, it only matters that deaths occurred, drives me up a wall. It is also impossible to understand antique and medieval medicine without a clue of which pathogens it was used against. We don’t like to think about parasites but they had them, just like some of us still do. Had to cope with head lice on your kids yet? What parasites did they have to cope with and how did those parasites alter their hygiene habits? Do some hygiene habits that seem disgusting to us, like not bathing for months, make sense with the parasites or pests (like mosquitoes) they had?
From cheese to beer, microbes were also important in food production and of course spoilage and food poisoning. Some of these microbes may have left lasting effects on us today. For example, ancient and medieval Nubians have tetracycline in their bones that came from fermented dietary sources, probably beer (Nelson, Dinardo, Hochberg, & Armelagos, 2010). Centuries of tetracycline ingestion would be an ideal environment for the evolution of tetracycline resistance. Coping with antibiotic resistance will be one of the biggest challenges to medicine in the 21st century.
Paleomicrobiology has as much to offer to modern microbiology and public health as to history and archaeology. Ancient DNA and antigens can not only confirm the pathogen of historic epidemics and epizootics (showing us what these pathogens are capable of), but also allow us to trace the evolution of pathogens that we are still coping with today. Measles is a prime case of a pathogen that is predicted to have evolved in the medieval period (Furuse, Suzuki & Oshitani, 2010) and is still very relevant today. It would be exciting to be able to trace measles development with ancient DNA from the ancestral virus to today. Along with tracking the evolution of pathogens, their vectors and geographic range throughout time can provide us with valuable information. The current wrangling over the etiology, vector(s) and epidemiology of the plague will ultimately teach us a great deal about understanding zoonoses and becoming too fixated on our paradigms. It will also teach us something about the conditions in which emerging pathogens explode and about their persistence.
Drancourt, M., & Raoult, D. (2005). Palaeomicrobiology: current issues and perspectives Nature Reviews Microbiology, 3 (1), 23-35 DOI: 10.1038/nrmicro1063
Furuse Y, Suzuki A, & Oshitani H (2010). Origin of measles virus: divergence from rinderpest virus between the 11th and 12th centuries. Virology journal, 7 PMID: 20202190
Nelson, M., Dinardo, A., Hochberg, J., & Armelagos, G. (2010). Brief communication: Mass spectroscopic characterization of tetracycline in the skeletal remains of an ancient population from Sudanese Nubia 350-550 CE American Journal of Physical Anthropology DOI: 10.1002/ajpa.21340