“Certainly the virus” ofbird flu “H5N1 is worrying and must be monitored. What is worrying” for example in the case reported in the USA, in Texas, “is that cattle have become infected, therefore there has been a jump in species compared to the original virus. The human case is the of a breeding worker. As has happened in other cases, therefore, there is still no trace of human-to-human transmission. Of course, we need to monitor, we need to pay attention to this virus because it can somehow give us surprises.” This was highlighted to Adnkronos Salute the virologist Massimo Clementi.
“There has been very strict control for some time, perhaps mindful of previous experiences – observes the expert, also commenting on the report of the European authorities ECDC and EFSA -. Above all, veterinary healthcare is truly carrying out a control activity worthy of praise, because everything that is there comes out. It is obviously an activity somewhat favored by the fact that livestock farms are better controlled than wild fauna, but in any case there is certainly very good control. Now it is certainly necessary to maintain vigilance and try to carefully develop safeguards to be put in place if it is necessary to limit the damage of human-to-human transmission. Because initially, even human-to-human transmission occurs in small communities, in small areas and should be stopped there. It is possible if there are the means to do so. It's clear that this is very important.”
The pandemic risk
What are the factors that could expose us to a greater risk of a pandemic? “There are several – analyzes the virologist who for years directed the Microbiology and Virology Laboratory of the San Raffaele hospital in Milan -. For example this element of the passage from species to species”, which is being observed more and more frequently. “As is known, the species of origin of this virus is the avian one, or rather there are different avian species. But now small epidemic outbreaks are being observed in different animals, always from livestock. This presupposes a species leapan adaptation of the virus to these new growth conditions and also presupposes a ability to genetically evolve the external proteins of the virusin the genes of the external proteins of the virus that show remarkable adaptability”.
Therefore, concludes Clementi, “we need to pay attention to this virus which was already one of the suspects, I would say perhaps more suspicious than others as a possible agent of a future influenza virus pandemic. It would not be the first “flu pandemic” and possibly will not be the last. There have been others and sometimes they were alarms that went somewhat amiss. Everyone will remember A/H1N1, the so-called 'swine flu' virus. That virus was due to a mix of various influenza viruses, it became human but still did not cause great concern because it was a very attenuated virus from the point of view of pathogenicity. In any case, a pandemic risk is possible.
Pregliasco: “Danger and terror no, attention yes”
“Danger and terror, no, but attention, yes.” This is the watchword in the face of avian risk for epidemiologist Massimo Ciccozzi. “Prevention and surveillance”, recommends the expert consulted by Adnkronos Salute. “The virus has passed from birds to mammals. Now what we must avoid is that it circulates among mammals. Because if it then mutates or carries out gene reassortment – he warns – no one tells us that, once it has passed to humans, it cannot be a human-to-human transmission”.
After the case of avian influenza identified in Texas in a worker in the dairy sector who had contact with infected cattle, “first of all we must be calm – Ciccozzi said – because since 2002 the human-to-human transmission” of this infection “has not yet been demonstrated But we must not let our guard down, we must keep it high at the level of prevention – warns the epidemiologist – to avoid circulation between mammals. And clearly we need surveillance, that is, we need to start understanding what is happening between the animals”.
“We know that the “avian” virus can pass from the animal to humans – recalls the specialist – Humans can already be infected from animals, but we must ensure that they do not contract an infection with a mutated avian virus. clade” of H5N1 which worries experts in the USA, where the pathogen is infecting dairy cows in several states, is “particularly under observation: if this reassorts or mutates, continuously passing between mammals – reiterates Ciccozzi – nothing tells us that then that mutation, once it reaches man, cannot make it make the transition from man to man”. This is the danger to be avoided.
Andreoni: “Virus adaptation creates concerns”
“There are hundreds of cases in the literature of H5N1 infections passing from birds to humans. It is certain that this passage in the USA from a mammal to humans is a sign of adaptation of the virus which creates concern”. Thus to Adnkronos Salute Massimo Andreoni, scientific director of Simit, the Italian Society of Infectious and Tropical Diseases, commenting on the second case of avian flu in the United States.
Could the H5N1 avian flu virus be the next disease X that brings a pandemic? “The mortality for this virus is around 50% so it could be disease around 30%, it is clear that if their human-to-human transmission were possible, which has not yet been confirmed, they could be very harmful.”
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