Researchers have witnessed two viruses, influenza A and respiratory syncytial virus, merge to form a single hybrid. virus.
While virus competition has been investigated in some detail, this new finding provides researchers with an unusual example of one virus co-opting another for its own benefits.
“This type of hybrid virus has never been described before,” virologist and lead author Pablo Murcia told The Guardian. “We are talking about viruses from two completely different families that are combined with the genomes and external proteins of both viruses. It is a new type of pathogenic virus.”
The hybrid virus looks like a gecko’s foot under the microscope, with respiratory syncytial virus (RSV) making up the legs and influenza A virus making up the toes.
It was discovered during a laboratory experiment designed to analyze interactions between viruses during infection to better understand clinical outcomes, pathogen behavior, and transmission.
Human lung cells were exposed to both viruses, as well as each virus individually as a control group. A variety of microscopy techniques then revealed threadlike structures consistent with a hybrid of both virus particles.
When these two viruses come together, influenza A appears to infect a greater number and a broader range of human cells. Influenza A particles were found to evade the immune system by displaying RSV surface proteins, giving the virus a survival advantage.
The hybrid also spread to cells that lacked influenza receptors, potentially allowing influenza A to travel further down the respiratory tract and into the lungs, causing more severe infections.
Unfortunately for RSV, this fusion is not a big deal, as the presence of influenza A significantly reduces its ability to replicate.
The experiment was limited to a laboratory setting, which “cannot fully capture the spatial and physiological complexity of the entire respiratory tract,” the researchers say.
However, the enhanced fitness of influenza when fused with a hybrid virus suggests that such blatant theft of another virus’s toolkit may play a role in viral pneumonia.
“RSV tends to go lower in the lung than seasonal flu virus, and the lower the infection, the more severe the illness is likely to become,” says Dr. Stephen Griffin, a virologist. a the University of Leeds who was not involved in the study.
“It’s another reason to avoid getting infected with multiple viruses, because this [hybridisation] it’s likely to happen even more if we don’t take precautions to protect our health,” he says.
Influenza A alone causes more than 5 million hospitalizations each year, while RSV is the most common cause of acute lower respiratory tract infections in infants, and reinfection is common later in life.
The study “raises questions about the fundamental rules that govern viral assembly,” and there could be other hybrid viruses yet to be discovered, the researchers write.
“Respiratory viruses exist as part of a community of many viruses that target the same region of the body, like an ecological niche,” says virologist and lead author Joanne Haney.
“We need to understand how these infections occur within the context of each other to get a more complete picture of the biology of each individual virus.”
This article was published in Nature Microbiology.
Source: news.google.com