An extremely rare discovery: this virus infected a 61-year-old patient and caused her hepatitis.
He was temporarily baptized Human Circovirus 1 (HCirV-1). This virus so far unknownfrom the circovirus family, has just been identified by French scientists in a 61-year-old woman.
Indeed, it has been analyzed and studied by several researchers in France from the Institut Pasteur, the Necker-Enfants Malades Hospital AP-HP, Inserm within the Imagine Institute, the University of Paris Cité and the National Veterinary School of Alfort (EnvA).
The results of this discovery were published in the journal Emerging Infectious DiseasesJanuary 3, 2023.
Cas rare
In more ways than one, this is a rare case. First of all, it’s the first pathogenic circovirus for humans.
Moreover, “while the passage of animal viruses to humans is regularly reported in the scientific literature, it is rare for a new virus to be identified in Europe in a patient“, emphasizes the Pasteur Institute.
While some circoviruses are pathogenic for animals and can be vaccinated, particularly in pigs, this is the first circovirus pathogenic for humans.
Genomic sequencing
The patient was followed following a heart and lung transplant performed 17 years earlier. But it’s the occurrence in her unexplained chronic hepatitiswith few symptoms, which led doctors to perform a genomic sequencing on samples of pathological tissues.
The patient’s symptoms remained mild, and the identification of this virus is linked to the fact that she was closely monitored because of her double transplant.
“The involvement of HCirV-1 in hepatitis was then demonstrated through the analysis of samples from the patient taken in previous years for her follow-up as part of her transplants. The results showed that the genome HCirV-1 virus was undetectable in blood samples from 2017 to 2019, then peaked in September 2021.”
The role of this unknown virus might thus be demonstrated in liver damage (2 to 3% of liver cells were infected).
Concretely, “once this virus had used the resources of the liver cell to multiply, it destroyed it”.
“After a antiviral treatment, the liver enzymes returned to a normal level in the patient, testifying to a cessation of hepatic cytolysis”, reassure the scientists.
Public health issue, PCR test
“The origin of the virus, circulating in humans or of animal origin, remains to be identified, as well as the source of the infection itself (contact, food, etc.)”, recalls the Institut Pasteur.
That being so, this discovery is far from useless since it allowed develop a PCR test now available for the diagnosis of hepatitis of unknown origin. However, many cases occur regularly.
“Cases of acute hepatitis reported in children in the United Kingdom and Ireland last April and reported by the WHO are a reminder of this”, underlines the Institute.
“It is also essential to have the ability to identify a new pathogen when an infection is unexplained and to develop a diagnostic test, because potentially any new case of infection by an emerging pathogen in humans can witness the start of an epidemic”, concludes Marc Eloit.
The latter is the co-author of the study, head of the Pathogen Discovery laboratory at the Pasteur Institute and professor of virology at the National Veterinary School of Alfort (EnvA).