So for this session and the rest of the meeting my laptop decided it no longer wanted to hold a charge so I was relegated to using old school methods of taking notes...my notebook and a pen! Gasp.
Didier Raoult, Faculte de Medecine; IHU Mediterranee Infection
Paleomicrobiology: Human Infections and Antiquity
Needless to say there's a lot of disease in our human history leaving an indelible mark...that we can find in frozen tissues, fixed tissues, mummies, bone and teeth. The most popular technique or perhaps the most used methodology you would start with in detection of pathogens is PCR.
But there are limits to PCR on ancient material:
For the longest time there was quite a bit of debate about what actually caused the Black Death? Was it indeed bubonic plague or a schlew of viral hemorrhagic fevers that had a long incubation period (as suggested by Scott and Duncan in their 2004 article).
Prior to Scott and Duncan's article, in 2000, Raoult's group had found evidence of Yersinia pestis in teeth by a method called "suicide PCR"
However they state in their article:
There have been several studies, before, during and since that time, providing evidence of the survival/longevity of pathogens within samples:
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Didier Raoult, Faculte de Medecine; IHU Mediterranee Infection
Paleomicrobiology: Human Infections and Antiquity
"Everything was called plague back then..."There was the Thucidides plague in Athens, the Antonine plague, Justinian plague, Black Death,then the post Columbian era syphilis and 'eruptive fever' (measles and smallpox) followed by the great wars and lice; Douai (18th century), Napoleon (19th century), WWI in the 20th century and the Bolshevic revolution.
Needless to say there's a lot of disease in our human history leaving an indelible mark...that we can find in frozen tissues, fixed tissues, mummies, bone and teeth. The most popular technique or perhaps the most used methodology you would start with in detection of pathogens is PCR.
But there are limits to PCR on ancient material:
- Really you can only go after short fragments 100-300 bps
- You have to worry about PCR inhibitors in the preservative matrix or sample itself
- Contamination of modern samples/DNA with the ancient during processing or handling
- Chemical alteration of the DNA
For the longest time there was quite a bit of debate about what actually caused the Black Death? Was it indeed bubonic plague or a schlew of viral hemorrhagic fevers that had a long incubation period (as suggested by Scott and Duncan in their 2004 article).
Prior to Scott and Duncan's article, in 2000, Raoult's group had found evidence of Yersinia pestis in teeth by a method called "suicide PCR"
- Suicide PCR methodology permits primer pairs to be used only once, but multiple sets of primers could be tested until an amplicon of the expected size is yielded. This amplicon then has to be sequenced to confirm its identity
However they state in their article:
"The report that DNA specific for Y pestis was amplified from 16th and 18th century human teeth believed to be from French plague victims and 14th century French Black Death victims has not been confirmed and the results have been ascribed to contamination."So the debate continued. Then in 2012 another technique was developed called Immuno-PCR which combines the power of PCR to detect protein associated with Yersinia pestis with ELISA to confirm exposure to Yersinia pestis by using a mouse monoclonal antibody against Y. pestis. Raoult's group used this to detect evidence of Y. pestis in the teeth (dental pulp) of humans who presumably died of plague.
There have been several studies, before, during and since that time, providing evidence of the survival/longevity of pathogens within samples:
- Ayyadurai, Saravanan, et al. "Long-term persistence of virulent Yersinia pestis in soil." Microbiology 154.9 (2008): 2865-2871.
- Biagini, Philippe, et al. "Variola virus in a 300-year-old Siberian mummy." New England Journal of Medicine 367.21 (2012): 2057-2059.
- Drancourt, Michel, et al. "Detection of 400-year-old Yersinia pestis DNA in human dental pulp: an approach to the diagnosis of ancient septicemia." Proceedings of the National Academy of Sciences 95.21 (1998): 12637-12640.
- Drancourt, Michel, et al. "Bartonella quintana in a 4000-year-old human tooth." The Journal of infectious diseases 191.4 (2005): 607-611.
In talking about vectors of transmission - we sometimes fail to appreciate the Louse, human body lice which makes it unnecessary for humans to always be in contact with rats/mice for disease transmission. The human body louse can do the trick just fine in human to human transmission. Louse-borne diseases include:
- Borrelia recurrentis
- Rickettsia prowaskii
- Bartonella quintana
- Yersinia pestis
When we look back in time we can see that there is evidence of louse borne disease outbreak in Napoleon's grand army in Vilnius and a louse borne outbreak of Typhus in Douai 1710-1712.
If you have continuing interest in paleomicrobiology check out Dr. Raoult's book on the subject or his talk at UNIL from 2014, in fact the presentation he gives in this video is very similar to the presentation he gave at ASM this year. Below...an excerpt from my notes.
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