Cell Host and Microbe: Another batch of potential human animals with the flu virus has been discovered!

On July 28th, the Friedrich Lefler Institute in Germany (the world's first virus research institution) joined forces with the University of Freiburg in Germany, the University of Veterinary Medicine in Hanover, the Royal Veterinary College, the Animal and Plant Health Service, the University of Helsinki in Finland and the Icahn School of Medicine in Mount Sinai, USA, to discover a number of potential human-to-animal swine influenza viruses through the detection and analysis of large-scale European pig data sets.
published in Cell Host and Microbe, "Surveillance of the European Domestic Population Pig Pig S. Emerging Reservoir of The Potentially Zoonotic Swine Influenza A Viruses".
from April 2015 to January 2018, researchers conducted a 34-month surveillance of swIAV (swine influenza virus) in 17 European countries.
samples of 18,313 pigs with respiratory diseases were collected from 2,457 separate farms during a routine veterinary visit.
surprise, the researchers found that as many as four major and several minor swIAV genealogy clusters were identified in more than 50 percent of sampling farms across Europe.
and regionalization, even the common circulation or common circulation of several subtypes at the same level, has led to the diversification of genotypes through frequent rearrangement among viruses.
further, the team selected 292 virus isolates derived from cell culture and two nasal swab samples for full-length sequencing of HA and NA fragments.
results once again validate the results of various IAV (influenza A) strains caused by intensive and continuous recombinant events in pigs.
these strains carry IGS (internal genome segment, internal genome sequence/internal genome fragments) from the 2009 pandemic virus; (N2) introduced six inpoule internal genomic fragments (IGS) in the background; this heavy matching (H3N2) has become endemic in pigs in Europe, but expresses a difference between ha and NA proteins, the key protein amino acids of the virus, and the strain of the virus in a human pandemic.
system evolutionary tree analysis also supports this view -- the European swIAV system development analysis reveals new HA/NA combinations and previously unknown genotypes.
of course, in the small series, the recombination and rearrangement between viruses is very frequent and common between influenza virus strains, it is this frequent recombination that led to the emergence of the influenza pandemic in the vagaries of the genome or new strains.
, does these new recombinant strains really escape human immunity and cause a pandemic? To analyze whether the current circulating swIAV has MxA resistance (the antiviral protein MxA has been shown to be a key inhibitor of IAV), the researchers analyzed 10 isolated strains with different genotypes (selected swIAV isolates represent different genotypes, subtypes, and lineages, these viruses have polymorphic amino acids in the NP, these amino acids are related to human MxA resistance) whether there is mxA resistance mutations, and in previously established human MxA genetically modified (hAtg)
surprise, the mouse model showed influenza-like epithets after infecting the target strain, proving that there was a large proportion of the recombinant strains that could cause human immune escape.
ferrets are thought to be a model for the spread of influenza in human animals, helping to assess the potential of the virus's zoonotic disease.
, the researchers selected three strong strains to study their propagation dynamics in ferrets.
mild to moderate respiratory signs (drowsiness, sneezing, breathing difficulties, elevated body temperature) were observed in all vaccinated animals.
, however, serum conversion is carried out only when exposed to snowm in isolated strains with huMxA resistance, and the virus is at risk of aerosol transmission.
immediately followed, does the recombinant new influenza virus mean the creation of new antigens? With this in question, the researchers selected 24 representative virus isolates for antigen spectrometry through blood clotting suppression (HI) and viral neutralization (VN) analysis.
results detect emerging swIAV recombinant viruses that can express different HA on antigens, and the emergence of these new antigens is likely to be enough to escape existing human immunity.
However, there is no need to panic too early.
has previously shown that the differences in antigens observed in the serum of infant ferrets are not necessarily similar to the reactivity of adult serums, as human exposure to influenza viruses has a long history and complexity.
to better characterize whether the body is resistant to these recombinant influenza viruses, researchers are using plasma from healthy adults with a complex history of influenza exposure to explore potential cross-reactivity, as it will better indicate the likelihood that certain viruses may cause zoonotic infections or even pandemics.
a total of 21 swIAV isolates with different HA subtypes or broad antigen diversity were microneutralized and tested according to the antigen map.
results showed that most healthy volunteers who had recently been vaccinated were immune to most of the swIAV isolates tested, but some test samples showed lower neutrality, suggesting that these individuals may be more vulnerable to certain swine flu viruses.
small editor can not help but think that after the impact of the new crown epidemic, people continue to realize that the decision is not a strong type of protection, but the omission of the "leakage", any link of negligence is to defeat all efforts to start.
the low immunity of human serum to the isolated influenza A virus pool in this paper, it is the beginning of a new human-animal disease pandemic that may trigger humans.
We also hope that more similar studies will guide our disease development and vaccine research.
.