Plague genome

[237SJ]

I have read that scientists have reconstructed the plague genome from the dental pulp and bones of plague victims buried in London. If the disease killed people in an average of three days, how come there was enough DNA in their teeth and bones to get this result? Could it be that some people were able to harbour the disease for quite a lot longer than three days?

[Buenchico]

Bones are living tissue, with their own blood supply. Any organism which is in the blood being circulated by your heart will therefore enter your bones almost as soon as it enters your bloodstream.

Chris

[Sqad]

The plague organism is a living organism and as Buenchico says can be distributed throughout the body tissues.

When the host dies and then the organism dies, the DNA chemistry which in the true sense is not alive, lives on and can be recovered and identified, years later.....perhaps even hundreds of years later.

There is little evidence from reports that i have seen that the plague could remain in the human body....unannounced so to speak without producing symptoms.

[237SJ]

Thank for your answers. The other thing I found fascinating was the article said that compared with modern plague, the disease had hardly changed in 660 years.

[beso]

Indeed human DNA has been extracted from Neanderthal human bones at least 38,000 years old and Denisovan human bones of similar antiquity.

[beso]

Another interesting fact about The Plague is that it is somehow related to HIV. Populations such as in Europe that have been exposed to Plague (and hence made up of the descendents of survivors) have a higher resistance to developing AIDS.

[Sqad]

beso,,,that is quite interesting...never heard that before and also unusual as HIV is a virus and plague is a bacterium, an unusual marriage for cross resistance.

[beso]

It depends on what is meant by the Plague. The plague involved in the HIV resistence was not a bacterial type but a viral haemorrhagic fever.

http://www.eurekalert...-03/uol-bdw031005.php

[wildwood]

//The other thing I found fascinating was the article said that compared with modern plague, the disease had hardly changed in 660 years.//

In the earlier days there were no modern medicines so the organisms had no reason for mutations to become more productive as the then present form was quite successful.

[beso]

The presence of antibiotics has certainly pushed organism to change. However some recent finds of ancient preserved bacteria has revealed they already posessed genes for resistance to completely synthetic antibiotics that had never been present in nature.

Bacteria are incredibly highly evolved organisms with an amazing ability to quickly adjust their details to the environment no doubt because of their arsenal gene variants.

Selection pressures quickly bring these genes into the fore but it has also been discovered that the presence of poisons in their environment actually stimulates the organisms to increase its mutation rate. This is also a key to their adaptibility.

One change that is almost universal in infectious diseases is the propensity to reduce their virility over time. A host that keeps walking is better for transmission. It would be interesting to see the how the genes of modern samples compare with the early and late varieties of the plague.

There have been relatively few case of the plague over the past few centuries to give it an opportunity to change its genome. This is one of the advantages of widespread vacination. It denies the opportunity for the development of new strains that can be resistant to antibiotics.

[Sqad]

beso...thanks for the link.....didn't know that viral haemorrhagic disease was classed as "a plague."

Sounds a bit like Ebola.

[venator]

As it was recovered from teeth, are the scientists sure it wasn't the plaque genome they found?

[Sqad]

venator ;-)

[sandyRoe]

Aren't there still occasional outbreaks in remote parts of Asia? Can some people, or animals, act as hosts and not suffer the worst effects of the disease?

[beso]

In the case of the classic bacterial plague the vector is the flea. Doesn't seem to bother them too much. Killing the vector would not be a smart move for an infectious organism.