Influenza A viruses have pandemic potential and are among the most dangerous viral pathogens. Depending on the host of origin, influenza A viruses are classified as, for example, bird flu or swine flu viruses. They are in a constant state of evolution and their zoonotic potential puts immunologists worldwide on alert.
They are mutation-prone and adapt to different environmental or host changes through point mutations and segment reassortment. The high rate of evolution of influenza A viruses makes them dangerous. The global spread of an avian influenza with the new pathogen H5N8 is a legitimate public health concern. Close contact between poultry and humans is a prerequisite for infection. On 18 February 2021, the World Health Organisation was informed by the IHR contact point of the Russian Federation of 7 human cases of H5N8 avian influenza. The patients had been employed in poultry farms. 5 of the 7 asymptomatic patients were female. The age range was from 29 to 60 years. Previously, 101,000 out of 900,000 egg-laying hens on poultry farms had died as a result of H5N8 infection between 3 and 11 December 2020. The regional veterinary laboratory conducted investigations due to this high mortality rate and discovered the H5N8 avian influenza virus (clade 2.3.4.4b).1
On 4 October 2018, a white-tailed eagle had already died an unnatural death in Germany after infection with this H5N8 (clade 2.3.4.4b). The H5N8 subtype of clade 2.3.4.4b has a high reassortment tendency. Infection with these viruses is associated with a high mortality rate for the affected birds. The virus does not only threaten birds from the breeding farm. Even threatened raptor species - such as the white-tailed eagle - are not spared.2 Highly pathogenic avian influenza viruses (HPAIV) subtype H5N8 of clade 2.3.4.4b have not only been discovered in Russia. Infected wild birds have died from the infection in Denmark, Germany, Ireland, the Netherlands, the United Kingdom, Israel, Japan and South Korea.3 In Japan and South Korea, the H5N8 subtype (clade 2.3.4.4b) has led to the emergency slaughter of more than 20 million birds in poultry farms.4
No interhuman transmission of subtype H5N8 (clade 2.3.4.4b) has been observed so far. There have also been no subsequent cases in the human host organism. On 6 April 2021, the German Federal Government published the following information on this subject: "To the knowledge of the Federal Government, 117 outbreaks in farms and five outbreaks in zoos with captive birds (poultry and other captive birds) as well as 962 cases in wild birds have been detected in Germany since 30 October 2020 (as of 18 March 2021, 11:00 a.m.)."5
What do swine flu, Ebola, SARS, MERS and COVID-19 have in common? They are all zoonoses, for which humans and their consumption behaviour are not entirely innocent.6-9 Around 60% of human infectious diseases have an animal origin.10 In many cases, the virus reaches humans via farm animals. An increase in zoonoses can be observed worldwide. The reasons for this could be the increasing clearing of forests. These are connected, among other things, with the needs of livestock farms. In the livestock farms themselves, the animals are so closely packed together that infectious diseases can spread rapidly. The consequences of climate change are not making things any better. In addition to viral pathogens, bacterial pathogens should not be ignored. Increasing antibiotic resistance is strongly associated with the use of antibiotics in livestock farms.11-17
Perhaps we will soon have this pandemic behind us. But it will not solve the problem. Mankind should seriously consider whether the way we live and consume should be continued in the future - with the knowledge and experience from the last pandemic. Responsibility must not be passed on to fellow human beings. Every individual must become aware of his/her responsibility for our planet. Consumer behaviour must change drastically. As a society, we can no longer afford to carelessly buy factory farmed products for our daily meat consumption. Besides the risk of zoonoses and pandemics, it is also ethically unacceptable.
References:
1. https://www.who.int/csr/don/26-feb-2021-influenza-a-russian-federation/en/
2. https://www.fli.de/de/presse/pressemitteilungen/presse-einzelansicht/wissenschaftler-weisen-erstmals-toedliche-vogelgrippe-infektion-beim-seeadler-nach/ (English title: First evidence of fatal infection of white-tailed sea eagles with avian influenza)
3. Baek Y. G. et al. (2021). Multiple Reassortants of H5N8 Clade 2.3.4.4b Highly Pathogenic Avian Influenza Viruses Detected in South Korea during the Winter of 2020–2021. Viruses 2021, 13, 490.
4. Shi W. et al. (2021). Emerging H5N8 avian influenza viruses:The global spread of H5N8 avian influenza viruses is a public health concern. Science. Vol 372; Issue 6544.
5. https://dserver.bundestag.de/btd/19/282/1928260.pdf
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7. Jones B. A. et al. (2013). Zoonosis emergence linked to agricultural intensification and environmental change. Proc Natl Acad Sci U S A. 2013;110(21):8399-8404.
8. Wiebers D. O. et al. (2020). What the COVID-19 Crisis Is Telling Humanity. Neuroepidemiology. 2020;54(4):283-286.
9. Leibler J. H. et al. (2009). Industrial food animal production and global health risks: exploring the ecosystems and economics of avian influenza. Ecohealth. 2009;6(1):58-70.
10. https://www.unep.org/resources/report/preventing-future-zoonotic-disease-outbreaks-protecting-environment-animals-and
11. Morand S. et al. (2021). Outbreaks of Vector-Borne and Zoonotic Diseases Are Associated With Changes in Forest Cover and Oil Palm Expansion at Global Scale. Front Vet Sci. 2021 Mar 24; 8:661063.
12. Afelt A. et al. (2018). Bats, Coronaviruses, and Deforestation: Toward the Emergence of Novel Infectious Diseases?. Front Microbiol. 2018; 9:702. Published 2018 Apr 11.
13. Bonilla-Aldana D. K. et al. (2019). Brazil burning! What is the potential impact of the Amazon wildfires on vector-borne and zoonotic emerging diseases? - A statement from an international experts meeting. Travel Med Infect Dis. 2019 Sep-Oct; 31:101474.
14. White R. J. et al. (2020). Emerging zoonotic diseases originating in mammals: a systematic review of effects of anthropogenic land-use change [published online ahead of print, 2020 Jun 2]. Mamm Rev. 2020;10.1111/mam.12201.
15. Manyi-Loh C. et al. (2018). Antibiotic Use in Agriculture and Its Consequential Resistance in Environmental Sources: Potential Public Health Implications. Molecules. 2018;23(4):795. Published 2018 Mar 30.
16. Landers T. F. et al. (2012). A review of antibiotic use in food animals: perspective, policy, and potential. Public Health Rep. 2012;127(1):4-22.
17. Iwu C. D. et al. (2020). The incidence of antibiotic resistance within and beyond the agricultural ecosystem: A concern for public health. Microbiologyopen. 2020;9(9):e1035.