Avian flu “dangerous for humans”. Virologists do not rule out another pandemic –

Will bird flu be the next pandemic? «It is highly possible» according to Arnaldo Caruso, president of the Italian Society of Virology (Siv-Isv), who in an interview with Adnkronos Salute does not mince words on the fears raised by the epidemic growing among dairy cattle in the USA, due to a highly pathogenic strain of H5N1 virus also found in fragments in pasteurized milk sold overseas. In the scientific community “there is great concern”, explains the expert who has just returned from Barcelona, ​​where he participated in the Congress of the European Society of Clinical Microbiology and Infectious Diseases (Escmid). «The passage of avian flu into mammals and the circulation in these animals – he warns – is a step forward towards man». The specialist, full professor of microbiology and clinical microbiology at the University of Brescia and director of the Microbiology Laboratory of the Asst Spedali Civili, paints a picture «perhaps pessimistic-he admits-but unfortunately we must not put our heads in the sand. Instead, we need to be realistic and prepare”, warns Caruso. Thinking regarding a future pandemic emergency, he underlines, “the avian virus is the only one that really worries” for more than one reason. First of all because “it is an influenza virus which as such is transmitted by air, the most effective in terms of contagion”.

The pathogen, then, is extremely widespread: “Wild ducks are carrying it everywhere, which we now also see in our cities, in our ponds, in our waterways.” And it is changing: «Not only H5N1 – specifies the expert – but various strains of avian virus are changing, at the level of multiple surface receptors, in order to adapt to humans. An increasingly easier leap, following it has passed to mammals and it circulates among mammals.” We are therefore faced with «not one avian flu, but several avian flus – Caruso points out – which have entered the mammal and are all potentially dangerous for humans. They are worrying because the circulation in mammals indicates that the virus is evolving in a clear direction: it has taken a path which inevitably, sooner or later – predicts the president of Italian virologists – will lead to its arrival in humans who will be able to become its reservoir and spreader” .

Will we lead to human-to-human transmission of the avian influenza virus? «It is inevitable – replies Caruso – that when the virus enters humans once more and once more, it will be able to take on that ‘fitness’, that is, that ability to adapt to human cells, which will allow humans to act as a reservoir and therefore as a diffuser for others men”. Beyond the cases known for exposure, professional or otherwise, to infected animals, “who knows how many times humans have already been infected, perhaps without presenting important symptoms – reasons the Siv-Isv president – Who knows how many avian viruses are trying to enter in man and how many times they have succeeded.” Therefore, if it is true that to date human-human contagion has never been confirmed for the avian virus, “it does not mean that human-human transmission is not already possible – observes Caruso – or that at least some strains have not already been stabilized in humans.” In short, «the situation is truly worrying – is the message – and requires stringent surveillance of animals, not just birds, of foods of animal origin consumed by humans and of humans themselves. It is essential that we are ready and prepared for a new possible future pandemic.”