THE ESSENTIAL
- After antiviral treatment, liver enzymes returned to a normal level in the patient, attesting to a cessation of hepatic cytolysis.
- The origin of the virus circulating in humans or virus of animal origin remains to be identified, as well as the source of the infection itself.
- A serological test to diagnose unexplained hepatitis is under development.
“It is rare for a new virus to be identified in Europe.” However, scientists from the Institut Pasteur have revealed that they have discovered, in recent months, the first circovirus linked to hepatitis in humans. The latter is provisionally named Human Circovirus 1 (HCirV-1). It is part of a family of highly resistant small DNA viruses, which was initially detected in 1974 in animal species.
In France, a sexagenarian was a carrier of the human circovirus
In a study published in the journal Emerging Infectious Diseases, the researchers explained how they identified this human circovirus. In March 2022, they were regularly following a woman, aged 61, who suffered from unexplained chronic hepatitis and showed few symptoms. The patient, who was on immunosuppressive therapy, had received a heart-lung transplant 17 years earlier. “We were able to access many samples over several years”, said Marc Eloit, the study’s final author, in a statement. As part of the research, the team used sequencing for microbial sequences to examine diseased tissue samples. After this analysis, they discovered “this new virus, which was unexpected to say the least”.
Human Circovirus 1: a virus responsible for liver damage
“We found no other viral or bacterial sequences. HCirV-1 shared 70% amino acid identity with the closest known viral sequences. The viral genome was undetectable in blood samples from 2017 to 2019, then became detectable at low levels in September 2020 and peaked at very high titers in January 2022”, can we read in the results. Multiplication of the virus in liver cells was revealed and demonstrated the role of human circovirus in liver damage. According to the authors, once this virus has used the resources of the liver cell to multiply, it destroys it.
PCR test: “know the cause of hepatitis” to “know if it is viral”
“To adapt the treatment and follow-up of patients, it is essential for us to know the cause of hepatitis, and in particular to know if it is viral”, underlined Anne Jamet, co-last author of the study. Thanks to this discovery, the researchers were able to develop a specific PCR test for the etiological diagnosis of hepatitis of unknown origin. It is now available to the medical community and “Achievable by any hospital laboratory”, added Anne Jamet.