Paleoparasitology and paleopathology. Synergies for reconstructing the past of human infectious diseases and their pathocenosis.

Paleopathology, a discipline studying human and animal diseases of the past, developed at the beginning of the 20th century. In 1910, the father of the discipline, Sir Marc Armand Ruffer, was the first paleopathologist to describe a human parasitic disease; urinary shistosomiasis on Egyptian mummies dating from the Dynastic period. Therefore, paleopathology and paleoparasitology have the same roots. However, since the beginning, these two fields did not evolve at the same scale, as the demography of paleopathologists, combined with that of anthropologists, increased much faster than the community of paleoparasitologists. On the other hand, since the last decade, a new field, paleomicrobiology, uses molecular techniques to identify ancient pathogen DNA. This approach has mainly been applied to bacterial pathogens, such as Mycobacterium tuberculosis, Mycobacterium leprae, Yersinia pestis, Rickettsia prowazecki and Bartonella quintana, due to the fact that anthropologists and paleopathologists are, for the moment, the main specialists dealing with molecular biologists. As the past human microbiological world should be considered as a whole, according to the concept of pathocenosis, it is time to establish a synergic link between paleoparasitology and paleopathology in order to significantly increase our knowledge of past human infections.