Tuberculosis is a good example.
In the 17thth centuries it was often the largest single cause of death among Europeans, particularly in cities . TB exerted enormous selective pressure on European populations. It not only killed large numbers of people, but killed them in their child-bearing years, preventing them from having more children and orphaning the ones they already had.
There is a good reason why so many Georgian and Victorian novels feature orphanages - they were ubiquitous in the cities of that time. TB began to decline long before effective medical therapies i. It also declined well in advance of improvements in living conditions and better nutrition . There is little evidence that public health measures such as quarantines were effective  , except for pasteurization of milk, which slowed transmission of bovine TB to humans.
Given the high death rate and the lack of other good explanations for TB decline, natural selection for resistance seems a plausible hypothesis. We know that cattle show heritable resistance to Mycobacterium bovis , the cause of bovine TB .
As in oncogenesis, viruses and bacteria are implicated in the majority of known historical epidemics. During the 20th and 21st centuries, an additional 78 epidemic outbreaks occurred, 10 of which spread across the globe. Highly infectious diseases continue to plague the planet in both urban and rural locations. And, thus far, only two epidemic diseases, namely smallpox Variola major and rinderpest Morbillivirus , have been eradicated by vaccines. As an example, and given the ambiguity regarding the assignation of, for instance, M.
Southern Africa is perfectly positioned to play an essential role in current palaeopathogenic research.
Since then, the formerly nascent field of aDNA research has significantly altered our understanding of the human evolutionary story. The likelihood of detecting ancient diseases, particularly from subtropical African conditions, poses some complications. Even those that do affect skeletal morphology e. Taphonomic alterations also mimic disease conditions which can induce interpretation errors pseudopathologies , even for experienced palaeopathologists Dutour, Microorganisms also differ in the propensity of their DNA to decay and undergo physicochemical changes over time.
Mycobacteria have highly resistant hydrophobic cell walls and DNA rich in guanine and cytosine. Conversely, T. It is consequently not surprising that M. But what are the implications of information concerning prehistoric pathogens for modern disease prevention and treatment strategies? And how can novel data concerning ancient pathogens and epidemics provide tangible benefits to living populations?
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These are important questions as the societal relevance of academic research is becoming an increasingly contentious topic. Few African tertiary institutions have the luxury of allocating funding to either established or novel research projects unless they are pertinent to the improvement of current societal issues. Bioarchaeological research is an expensive enterprise and it does not always attract the same degree of funding such as that driven by the need for economic growth and medical breakthroughs.
Second, and more controversially, it might also prove highly valuable in the development of new vaccines and, possibly, play a role in the discovery of novel pathogens that might pose significant future disease threats to humanity. The information derived from HTS and bioinformatic analyses of apDNA can be used to anchor pathogen mutation rates and reconstruct viral and bacterial evolutionary processes.
Genetic mutations occur through various mechanisms, including single nucleotide mutations, insertions or deletions and chromosome rearrangements. As mutations play an important role in pathogen evolution and virulence, information derived from apDNA sequences have much epidemiological potential. While these mechanisms are important drivers of microbial genetic diversity, they complicate efforts to define species and to trace the evolutionary history of microbial lineages.
Some studies have nevertheless addressed the age of bacterial pathogens that infected ancient humans, and many of these have provided significant insights into pathogen evolution.stessitape.ga
For example, following calibration of the evolutionary divergence within H. The genetic diversity of H. The characterization of historical Y. The genome sequencing of Y. This was the result of a single genetic mutation YMT affecting pathogen virulence and the ability of the bacterium to colonize and survive in flea intestines.
Genomics has also enabled the use of entire pathogen genomes to search for protective antigens that were impossible to identify with conventional technologies. Following the successful development of a vaccine against smallpox V. Recent genomic data have been used to identify vaccine antigens for specific Escherichia coli strains e. One of these entailed the acquisition of mutations derived from the H5N1 avian virus, and the result was the Spanish influenza pandemic.
The ensuing pandemic viruses of , , and all descended from the original virus. Thus, early in the pandemic, limited vaccine supplies that might have been misdirected to the traditional risk group the elderly were instead administered to younger persons, who benefitted most.
How Infectious Disease May Have Shaped Human Origins
This is important as history has taught us that disease is by far the most effective eradicator of our species. Past pandemics are much more than just ancient history. Helena Cave, South Africa at 2. The past provides a prologue for discussions regarding emerging diseases, whether it concerns the biological origins of a potential pandemic or its social repercussions Heymann, Disease epidemics are not new and they will continue to affect and potentially devastate human populations.
The severe economic and social repercussions of disease epidemics are clearly demonstrated by historical e. But the biological origin of a many prehistoric, historical and even contemporary causative pathogens remains mysterious. This is particularly important given the current global interconnectedness, which can put people at risk of diseases that emerge in distant locales.
The unique combination of an unrivalled archaeological record and a thriving and highly skilled academic community therefore places southern African archaeologists, geneticists and medical scientists in a prime position to explore past pathogenic influences and to contribute to the improvement of human health and longevity. All the authors wish to thank the University of Pretoria and the National Research Foundation for financial support.
Where did they originate? What natural factors have stalled the progression of diseases or made them possible?
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How does a microorganism become a pathogen? How have infectious diseases changed through time? What can we do to control their occurrence? Ethne Barnes offers answers to these questions, using information from history and medicine as well as from anthropology. She focuses on changes in the patterns of human behavior through cultural evolution and how they have affected the development of human diseases. Product details Format Paperback pages Dimensions Review quote "Ethne Barnes provides a readable account of diseases past and future and of how human habits influence disease.
Fascinating chapters include those on such infectious diseases as leprosy, tuberculosis, syphilis, malaria, smallpox, cholera, yellow fever, and HIV.