Változó éghajlat, változó környezet, változó kórokozók. Meddig tart a járványok kora?

Összefoglaló. Az eddigi összes világjárványt olyan zoonotikus kórokozók, vírusok vagy baktériumok okozták, amelyek könnyen tudnak emberről emberre is terjedni. Minden egyes felbukkanó fertőzés egészségügyi, társadalmi és gazdasági költségeket von maga után. Az országhatárok nem tudják hatékonyan korlátozni a betegségek terjedését. Az eddigi trendek alapján jóval több mint félmillióféle, zömmel teljesen ismeretlen vírus lehet képes embereket megfertőzni. Az ember által letarolt vagy urbanizált területeken olyan állatfajok lesznek dominánsok, amelyek kifejezetten jó kórokozó-fenntartók. A hangsúlyt mostantól kezdve a megelőzésére kell helyezni, melynek a feltételei végrehajtható tervek formájában adottak. A hatékony megelőzés költséges, de jóval olcsóbb, mint egy világjárvány gazdasági következményeit viselni. Summary. So far, all pandemics have been caused by zoonotic pathogens, viruses or bacteria that could easily spread from human to human. Emerging infectious diseases entail huge costs for the health system, as well as for society and economy in general. Experience tells us that national borders are insufficient to prohibit the spread of infectious diseases. Extrapolation from current trends suggests that the number of largely unknown virus species able to infect humans is well over half a million. Overall, we seem to lack knowledge about 90% of the pathogens of the world. A striking experience is that pathogens can jump hosts based on their standing genetic variation and phenotypic plasticity. Mutations tend to follow later and lead to evolutionary finetuning of the pathogenic lifecycle. Human activity has contributed a great deal to the current dangerous rise of emerging infectious diseases. Climate change induces migration, biological invasions, and a higher incidence of the encounter of species with potential pathogens. Invading species tend to disrupt local ecosystems, resulting in lower biodiversity and higher susceptibility to disease of the remaining endemic species as well as the agriculturally important, domestic plant and animal populations. Habitats devastated by human activity as well urban areas will be dominated by species (such as rodents) that can harbour several potential and actual pathogens. Urbanization is a major risk factor for several reasons, including the elevated temperature in cities that contributes to the increase in pathogen survival during winter and the high population density and consequential contact rate of the local human population. Globalization adds to the security hazard posed by pathogens. From now on, emphasis should be put on the prevention of pandemics, for which we have executable plans. One such plan is the DAMA protocol (Document, Assess, Monitor, Act). We must document the occurrence of potential pathogens in candidate host species. Then we assess the threat level associated with identified potential pathogens, followed by a systematic monitoring of the most dangerous pathogens, looking for early signs of potential outbreaks. Action means advice by experts on possible preventive measures by experts and their evaluation and execution by decision makers. Similar ecological diagnostics seem possible for biological invasions in general. Efficient prevention is costly, but considerably less so than bearing the economic consequences of pandemics by (re-)emerging infectious diseases.