A circovirus has been detected for the first time in humans by French scientists. Here is what we know and what to remember about this new virus.
French scientists from several research institutes reported, on January 3, 2023, in the journal Emerging Infectious Diseases the identification of a first circovirus in humans, hitherto unknown. baptized Human Circovirus 1 (HCirV-1), here is what we know about this virus which particularly affects the liver.
What is a circovirus?
“Circoviruses are naked, circular, single-stranded DNA viruses. They are the smallest known among those capable of affecting vertebrates“. This is how Marc Eloit, Head of the Pathogen Discovery Laboratory at the Institut Pasteur and Professor of Virology at the National Veterinary School of Alfort (EnvA), defines a circovirus. He is one of the authors of the first published study on HCirV-1.
Circoviruses generally affect animals in which they cause respiratory, renal or even reproductive problems. “In pigs, they are common. One of them is very pathogenic and a vaccine is widely used”, explains Marc Eloit. It was also in pigs that the first circovirus was identified in 1974. “The viruses of this family are also common in other species such as birds”, specifies the researcher.
How was it detected?
This first circovirus to affect humans was discovered in a 61-year-old patient. She had received a double heart-lung transplant seventeen years ago and was undergoing immunosuppressive treatment, which made it easier to identify the circovirus. “In immunocompromised people, viral infections are more easily identified than in others”, confirms Marc Eloit, before specifying that “this can be a first sign of a virus which we can then study in a population more general”.
Is it serious that a circovirus affects humans?
“Identifying a circovirus in humans is not an indication of seriousness or new emergence”, assures Marc Eloit. Especially since this virus has existed for many years, in a different form, and this patient may not be the first to be affected; only the first where this circovirus is clearly identified. “We may only be highlighting a virus that has been present for a long time and has remained ignored”, concludes the co-author of the first study.
He specifies that it is necessary to make the difference between “new” viruses and viruses “that we discover”, recalling that circoviruses already existed in the past. Even if the Human Circovirus 1 is very different from those of animal origin.
What is its link with hepatitis?
When analyzes were done on the patient, her constants revealed hepatitis without an identifiable cause. According to the Pasteur Institute“lVirus multiplication in liver cells revealed, demonstrating role of HCirV-1 in liver damage“. The tools developed to be able to ascertain the presence of this circovirus will help to better identify hepatitis. “There are many cases of hepatitis that remain unexplained. We have also received requests for access to diagnostic tools (PCR) for this virus which have been developed for the occasion.“, explains Marc Eloit.
Should we be worried about its possible proliferation?
“We do not yet know if it is a virus at risk for the non-immunocompromised general population”, affirms Marc Eloit. The discovery of this virus is recent, and much research still needs to be done to better discover it. To date, several questions remain unanswered, such as whether it results from an animal infection or if it circulates in humans.