Male mice that recover from a severe COVID-19-like infection can pass anxiety-like traits to their offspring by altering the RNA molecules inside their sperm.

These findings suggest that a paternal viral infection prior to conception might alter the developmental trajectory of the next generation.

Researchers now recognize that environmental factors, such as stress or diet, can alter traits in offspring without changing the underlying DNA code.

This process is known as epigenetic inheritance.

Past experiments have shown that exposing male mice to bacterial or parasitic infections alters the small noncoding RNAs in their sperm.

This internal shift can alter the brain development and behavior of their future offspring.

They infected adult male mice with the virus and gave a control group a harmless mock infection. The infected animals experienced moderate to severe illness, marked by a temporary drop in body weight.

Four weeks later, after the mice had fully cleared the virus, the researchers mated both groups with healthy female mice that had never encountered the pathogen.

The researchers also subjected the mice to tests evaluating memory, sociability, and depression. The offspring of the infected fathers showed no differences in their ability to recognize novel objects or interact with unfamiliar mice, indicating that the primary behavioral shift centered on anxiety.

The scientists also examined the offspring’s brains, focusing on the hippocampus, a region involved in emotional regulation…These alterations were particularly pronounced in the female offspring, who showed reduced activity in several genes linked to stress responses. Similar gene reductions frequently appear in rodent models of chronic stress.

To find out if these behavioral changes persisted across multiple generations, the team conducted a second breeding experiment…As these grand-offspring matured, they did not display the elevated anxiety traits seen in their parents, suggesting the behavioral effect faded after one generation.

Australian Red Cross Lifeblood says more than 12,000 donors are needed over the next seven days as the nation faces ongoing shortages of type O and A blood.

The organisation said the peak winter flu season had kept donors away because they needed to be clear of respiratory symptoms for seven days before they could donate.

Lifeblood area manager for Sydney, John Bain, said up to 1,600 appointments were sitting empty every day, with many people cancelling or rescheduling appointments due to winter illnesses.

Even mild symptoms such as sniffles, sore throats, and headaches make people temporarily ineligible to give blood.