Abstract
Infectious diseases and epidemics have always accompanied and characterized human history, representing one of the main causes of death. Even today, despite progress in sanitation and medical research, infections are estimated to account for about 15% of deaths. The hypothesis whereby infectious diseases have been acting as a powerful selective pressure was formulated long ago, but it was not until the availability of large-scale genetic data and the development of novel methods to study molecular evolution that we could assess how pervasively infectious agents have shaped human genetic diversity. Indeed, recent evidences indicated that among the diverse environmental factors that acted as selective pressures during the evolution of our species, pathogen load had the strongest influence. Beside the textbook example of the major histocompatibility complex, selection signatures left by pathogen-exerted pressure can be identified at several human loci, including genes not directly involved in immune response. In the future, high-throughput technologies and the availability of genetic data from different populations are likely to provide novel insights into the evolutionary relationships between the human host and its pathogens. Hopefully, this will help identify the genetic determinants modulating the susceptibility to infectious diseases and will translate into new treatment strategies.
Highlights
Infectious diseases and epidemics have always accompanied and characterized human history, representing one of the main causes of death
Despite progress in sanitation and medical research, infectious diseases represented a major killer; data published by the World Health Organization (WHO 2008, http://www.who.int/en/) indicate that about 15% of deaths in the world’s population are due to infectious and parasitic diseases, reaching about 41% in Africa
A pioneer in many fields of science, and in genetics in particular, was among the first to propose that, as infectious diseases had been a major threat to human populations, they had been acting as a powerful selective pressure and may be considered a major driver of evolution in our species [7]
Summary
Infectious diseases and epidemics have always accompanied and characterized human history, representing one of the main causes of death. Modern humans appeared in East Africa about 200,000 years ago, spread out from sub-Saharan Africa approximately 100,000 years ago, and subsequently colonized the rest of the world in a series of migratory events [1] During this process, humans encountered a wide range of different environmental conditions, including diverse pathogen species, and introduced changes in subsistence strategies that allowed the development of large, interconnected societies. With the development of urban centers, in about 3,000 BC, and increased communication between neighboring towns, human settlements became large enough to maintain diseases in an endemic form This is the case, for example, for measles; for the longest part of its history, measles has been preserved by sequential outbreaks in rural villages, until the density of human populations was large enough to facilitate and support the presence of the infectious agent as an endemic pathogen [3]. We have been witnessing the appearance and rapid spread of novel epidemics, first and foremost HIV/AIDS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
