This is mostly (though not exclusively) due to the multiple and consistent differences characterizing the exceedingly long list of the hitherto identified microbial pathogens, on one side, coupled with hosts' highly varied immune responses against the aforementioned agents, on the other. Within such a challenging and intriguing context, remarkable lessons have been taught by the COVID-19 pandemic, which has reminded us, once again, that 75% of emerging infectious diseases (EIDs) are known to originate from one or more animal reservoirs (1).
In this respect, it is well established that RNA-viruses like those causing influenza in people and animals alongside SARS-CoV-2 - the betacoronavirus responsible for the COVID-19 pandemic - are extremely prone to develop mutations in their genetic make-up. This allows them to elude host's antiviral immunity conferred either by previous infections or vaccinations, thereby enabling them also to infect and progressively adapt to new species. This is exactly what's happening, nowadays, with the highly pathogenic avian influenza (HPAI) A(H5N1) virus, for which a rapid and significant host range expansion has been recently described, thus including even geographically and phylogenetically distant domestic and wild avian and mammalian species (2).
The propension to undergo genomic mutations typically possessed by RNA-viruses and, to a lesser extent, also by other microbial pathogens, both viral and non-viral, could be amplified by a prolonged exposure to solar and, even more, to nuclear radiations, a possibility made especially alarming and plausible, at the same time, by the current war theatres in Ukraine as well as in Near-Middle East (3).
Within such framework, adequate attention should be additionally payed to the strong environmental resistance of given microorganisms like the Monkeypox virus (MPXV) and the African Swine Fever Virus (ASFV), both of which are DNA-viruses. Indeed, as a consequence of heavy storms or fast moving winds and currents, these two alongside other pathogens particularly resistant to physical and chemical inactivation could be transferred far away from the site where infected hosts shed them into the surrounding environment (4). Regretfully, the role of environmental drivers is often overlooked in the context of eco-epidemiological investigations aimed at assessing the origin(s) of infectious infectious disease outbreaks.
In conclusion, preventing the occurrence and subsequent spread of EIDs and, more in general, of infectious diseases, appears to be of paramount importance. This could be done, in primis, through mass vaccination campaigns and through the development of "ad hoc" mathematical and statistical models aimed at foreseeing infectious disease evolution. In order to achieve these ambitious goals, multidisciplinary and a tight intersectorial collaboration between human and veterinary medicine should be viewed as absolute prerequisites within a holistic approach and a sound One Health perspective, thus taking into special account the remarkable lessons taught by the COVID-19 pandemic.
Historia Magistra Vitae!
References
Casalone C., Di Guardo G. (2020).
CoViD-19 and mad cow disease: So different yet so similar. Science.
DOI: https://www.science.org/doi/10.1126/science.abb6105#elettersSection.
Di Guardo G. (2024). Consideration of environmental aerosols.
Veterinary Record 194(3):119.
DOI: 10.1002/vetr.3930.
Di Guardo G. Highly Pathogenic Avian Influenza A(H5N1) Virus: How Far Are We from a New Pandemic? (2025a).
Veterinary Sciences 12(6):566.
DOI: 10.3390/vetsci12060566.
Di Guardo G. (2025b). Nuclear catastrophes: Have we truly learned from history? BMJ.
DOI: https://www.bmj.com/content/388/bmj.r319/rr-5.