Bird flu “flies, flies” (to be precise, wild birds which are also the “source of viral evil”) to many countries and infects in its passage a multitude of other species in recent years: from poultry to cats, foxes, seals, sea lions, mink and now goats and cows.
But humans are also on the list of infected species – indeed very recently in the US, for the first time, a cow infected a human with the H5N1 strain of influenza A, raising fears that bird flu may have undergone mutations capable of making easy and its transmission between people (with all that this implies for its future and ours, as the still fresh example of the COVID-19 pandemic proved).
The danger
On April 3, when the American case of bird flu in humans became known, the joint report of the European Center for Disease Control and Prevention (ECDC) and the European Food Safety Authority (EFSA) came from the other side of the Atlantic regarding with the factors contributing to the spread of H5N1.
An exhibition that also had a Greek signature, that of Dros Angelikis Melidou, assistant professor of Molecular Microbiology – Virology at the Aristotle University of Thessaloniki and ECDC’s main expert on Respiratory Viruses. Vima-Science contacted Dr. Melidou asking for answers to the new “viral” questions raised by the global spread of bird flu. Because she “flies” around the world and with her… fear flies again.
We initially asked Dr. Melidou if recently the bird flu shows tendencies to adapt to the human body, which could make it easy to transmit it between people.
As he answered “Human infections with avian influenza remain rare and no ongoing human-to-human transmission has been observed. To date, despite the large numbers of infected birds, no bird flu infection has been recorded in humans in EU countries. There is no indication that the virus has adapted to humans – and this also applies to the recent US case of human infection from a cow. Based on the available data, the risk of human infection with circulating H5 avian influenza viruses remains low for the general population in the EU. For people occupationally or otherwise exposed to infected animals, the risk is considered low to moderate”.
A measurable opponent
However, the strain of avian flu that is mainly circulating at the moment, H5N1 is not “innocent”. “It has shown the ability to make some evolutionary steps towards its adaptation to mammals while also showing a tendency to recombination – that is, mixing genetic material of different strains that lead to new combinations after co-infection. However, so far, recombination has only occurred in subtypes of the virus that affect birds – no such events have occurred with avian influenza viruses circulating in swine or humans.” noted Dr. Melidou.
Although human cases are not that many worldwide, the fatality rates clearly show that bird flu is a formidable opponent.
“Bird flu symptoms in humans are similar to seasonal flu, including fever, cough, muscle aches and fatigue. Upper respiratory symptoms are less common but the disease can lead to respiratory failure, acute respiratory distress syndrome (ARDS) and multiple organ failure. Atypical symptoms such as neurological can also appear. The mortality rate is around 50% worldwide. However, it should be noted that there is probably an under-reporting of mild or asymptomatic cases, which may lead to an overestimation of the mortality rate. explained the ECDC expert.
Dr. Melidou emphasized that although it is impossible to predict when the next pandemic will emergethere are factors that could contribute to the risk of avian influenza reaching pandemic proportions, which were presented in the ECDC and EFSA report. “These are the evolution of viruses circulating in birds, the transmission of avian influenza strains between mammals – for example on fur farms where events of viral recombination, mutation and adaptation of the virus in mammals are facilitated. In addition, the human population is expected to be immunologically vulnerable to avian influenza strains, so if one of them achieves sustained human-to-human transmission, it could rapidly spread to the human population.”
Holistic approach
For all these reasons, continuous surveillance of avian influenza is required “because of its potential to evolve so that a strain could emerge in the future that could pose a pandemic threat” pointed out the ECDC expert and added that in this context, the EU is aiming for a holistic approach to bird flu surveillance, the so-called One Health approach: “Our holistic approach includes surveillance, early detection and rapid response to bird flu outbreaks. In our recent report we highlighted the need to strengthen surveillance targeting humans and animals in conjunction with genomic analysis and the sharing of country-by-country sequencing data. With regard to surveillance in humans, the ECDC recommends screening of severe cases of viral encephalitis/meningoencephalitis or cases with other atypical symptoms for avian influenza as well as targeted screening of individuals exposed to infected animals. In addition, any sample that tests positive for influenza A but does not concern a seasonal strain must be sent to specialized laboratories for further analysis.”
The lesson of COVID-19
In closing, Dr. Melidou emphasized that the COVID-19 pandemic reminded us all of our vulnerability to emerging communicable diseases and provided critical lessons about our preparedness and response to viral threats.
“Our experience with the COVID-19 pandemic has certainly led to improvements in some areas such as surveillance and data sharing, rapid development of vaccines and treatments, increased investment in public health, technological advances and the adoption of holistic health approaches but at the same time it showed important gaps that we need to close in order to be better prepared for future pandemics. Such is the equality of access to vaccines, the improvement in the communication of data to the population, the development of flexible legal and ethical frameworks to respond to emergency needs. Continued surveillance, investment and global collaboration for the One Health approach are pillars that will ensure the global community can prevent in the future or rapidly suppress new communicable health threats.”
Because we must not forget that human health is inextricably linked to that of animals in order not to… let the opportunity fly away next time to prevent the next pandemic threat that will surely come. In order not to experience what we experienced with COVID-19.
Is there a vaccine?
Given that bird flu is not an unknown viral enemy, as was the case with the pandemic coronavirus SARS-CoV-2, there is already a pro-pandemic vaccine against H5 strains which is approved in the EU, Dr. Melidou informed us. “This vaccine is intended to be given to protect people at risk of exposure to infected animals.”
In the EU there are other H5 vaccines available for use in the event of a bird flu pandemic.
“In such a pandemic scenario, these vaccines will need to be updated to cover the emerging pandemic strain, but the process is expected to be quick. The exact time frame in which a pandemic avian flu vaccine could be ready is difficult to predict and will depend on different factors such as the need to adapt the vaccine to the pandemic strain, the possibilities of scaling up vaccine production, the mode of distribution, etc. .etc.” the ECDC expert noted and added that there is already a vaccine available for poultry as well.
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