New Feline Hepadnavirus Identified

May 25, 2018
Kerry Lengyel

The death of an immunocompromised cat has led to the discovery of a previously unknown feline virus that may play a role in both human and veterinary research and health.

Jasper, the cat that the new hepadnavirus was first identified in.

Investigators from the University of Sydney were conducting a study to identify potential viral pathogens infecting domestic cats. But after performing high-throughput transcriptome sequencing of tissues from cats infected with feline immunodeficiency virus (FIV), they discovered a brand new virus.

A novel member of the Hepadnaviridae family, tentatively named domestic cat hepadnavirus, was discovered in a tissue sample from an FIV-positive cat that died of lymphoma.


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“Until now, we didn’t know that companion animals could get this type of infection,” said Julia Beatty, BVetMed, PhD, professor of feline medicine at the University of Sydney School of Veterinary Science and one of the study investigators. “We obviously need to understand [its] impact on cat health.”

The findings, published in the journal Viruses, explain how high-throughput transcriptome sequencing allowed the investigators to detect the hepadnavirus, which might otherwise be excluded or contained in immunocompetent individuals.

Once the team discovered the new virus in the lymphoma sample, they tested stored blood samples from multiple adult cats, finding even further evidence of infection. Investigators identified hepadnavirus in 10% (6/60) of FIV-infected cats and 3.2% (2/63) of non—FIV-infected cats.

“Finding a new virus responsible for disease is the first step in developing a vaccine to prevent infection,” said Kelly Diehl, DVM, DACVIM (SAIM), senior scientific and communications adviser at Morris Animal Foundation, which funded the study. “It’s especially exciting if the vaccine could prevent a future cancer from developing in immunocompromised or other vulnerable cats.”

Investigators said the higher prevalence of hepadnavirus detected in FIV-infected cats mirrors that seen in HIV-infected humans coinfected with hepatitis B virus.

While similar viruses can cause hepatitis and liver cancers in other species, there is no risk to humans or other pets from the newly discovered feline hepadnavirus. “Apart from its relevance for feline health,” Dr. Beatty said, “this discovery helps us understand how hepatitis viruses, which can be deadly, are evolving in all species.”

The investigators noted that additional studies need to be conducted regarding the natural history, epidemiology, and pathogenic potential of the newly discovered domestic cat hepadnavirus.