Rome, 4 May 2024 – The avian influenza virus it raises its head dangerously in the USA and the alarm reaches as far as Italy.
According to the virologist Burioni “there are no human-human transmissions”, but you still need to be careful.
The symptoms of the first infected man
In fact, it was recorded first human case linked to the epidemic that circulates among dairy cattle in the United States. The symptom presented by the first person infected by a bovine is one conjunctivitis with hemorrhage in both eyes, without visual impairment. The infected person is iThe worker of a Texas dairy company whose infection made headlines a month ago, bouncing around the international media. The description of the case is the subject of a letter to the editor published in ‘New England Journal of Medicine’, signed by experts from the Centers for Disease Control and Prevention (Cdc) in Atlanta, from the Texas Department of State Health Services and from the Texas Tech University Bioterrorism Response Laboratory in Lubbock, from the Texas Department of State Health Services in Austin. An image accompanying the correspondence: the photo of the patient’s eyes.
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American scientist Eric Topol fears hidden infections, according to whom “it is possible/probable that other people have been infected” from the avian virus A(H5N1) which is fueling the ongoing epidemic among cows in the USA, “but which have not been diagnosed”.
Let’s talk about “mild symptoms (a spontaneously resolved conjunctivitis, but a single case is not indicative) – says Burioni, professor of microbiology and virology at Vita-Salute San Raffaele University – and fortunately no human-human transmission. But be careful – he warns –, the virus tries.”
The study: the virus has been circulating for 4 months
According to the estimate contained in a study coordinated by the US Department of Agriculture and made available on the bioRxiv platform, before review by the scientific community, the highly pathogenic avian influenza virus A/H5N1 which is causing several outbreaks in cows in the United States, probably, it circulated in livestock for approximately four months before he was identified.
The study reconstructed the evolution of the virus, its transition from birds to cows and diffusion in livestock through the analysis of genetic sequences. One of the characteristics of influenza viruses is their ability to mutate and acquire portions from other viruses through a process called reassortment. According to research, in the avian flu virus that is infecting cattle uA key event of this type may have occurred towards the end of 2023, when the pathogen, which was circulating in birds, acquired parts of another low pathogenic avian influenza virus. This new feature may have allowed the virus to acquire the ability to infect and spread in cattle. The first infection, according to reconstructions, occurred between the end of 2023 and the first days of 2024. At that point, the transfer of livestock from Texas to other states played an important role which allowed the infection to spread, even asymptomatic, among the leaders. At the moment, it is difficult for researchers to make predictions, but there are several elements of concern. One is the identification of some variants which, “if they became dominant, could have phenotypes that increase the probability of transmission between different species”, we read. Furthermore, the possibility that the virus infects different animal species present on farms (for example pigs) “could lead to reassortment and the emergence of new strains that increase zoonotic risk”.
“It is possible/probable that other people have been infected” by the highly pathogenic A(H5N1) avian virus that is fueling the ongoing epidemic among cows in the US, “but have not been diagnosed”. The American scientist Eric Topol, executive vice president of Scripps Research, founder and director of Scripps Research Translational Institute, fears hidden infections, commenting on X on the letter to the editor published in the ‘New England Journal of Medicine’ with the “details of the first documented human case of influence
avian H5N1 in the pervasive epidemic of dairy cattle”. The infection affected a dairy worker in Texas, who showed conjunctivitis with hemorrhage in both eyes, without vision impairment, treated and resolved with the drug antiviral oseltamivir. No other symptoms for humans, whose close contacts have undergone prophylaxis with the same medicine and have not developed signs of contagion, the photo of the patient’s eyes is also reported.
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