Változó éghajlat, változó környezet, változó kórokozók. Meddig tart a járványok kora?
Authors: Földvári Gábor , Garamszegi László Zsolt , Szathmáry Eörs 
Published: October 2021

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.