Species barrier (epidemiology)
In epidemiology, the species barrier is the property of microorganisms to be able to colonize only individuals of one or a few species. It is the result of specific adaptations of the pathogen to its host or its vectors .
The species barrier is always relative, i.e. it does not rule out that pathogens break through the species barrier and develop new host populations . In order to overcome the species barrier, a contagious surface, reproduction on this surface, settlement , entry, reproduction and resistance to the immune system of the new host are necessary. Pathogens that have overcome the species barrier between different animal species and humans are, for example, the human immunodeficiency virus (HIV), the SARS coronavirus (pathogen causing severe acute respiratory syndrome ) and the avian flu virus H5N1 and avian flu H7N9 . The species barrier was also overcome in the so-called prion diseases . For example, bovine spongiform encephalopathy (BSE) was transmitted to cattle by feeding insufficiently decontaminated slaughterhouse waste from scrapie- infected sheep. In this context, a new variant of Creutzfeldt-Jakob disease (nvCJD) also appeared, which is presumably a transmission of BSE to humans.
Individual evidence
- ^ Sansonetti P .: How to define the species barrier to pathogen transmission? Bull Acad Natl Med. 2006 Mar; 190 (3): 611-22 PMID 17140099