In a new study published in mBio journal entitled “Discovery of a Novel Hepatovirus (Phopivirus of Seals) Related to Human Hepatitis A Virus“, researchers discovered a new virus that is the closest known relative to the human hepatitis A virus (HAV). It is found in harbor seals and was designated as phopivirus.

Hepatitis A is a contagious disease which is transmitted through physical contact or oral consumption of food/water. It is caused by the HAV, which after entering the bloodstream, targets the host’s liver where it multiplies and may cause acute liver failure. Patients infected with HAV may or may not experience symptoms. If symptoms occur, they can last up to 2 months, with patients infected with HAV experiencing signs of fever, nausea/vomiting, diarrhea, fatigue, loss of appetite and yellowing of the skin.

While investigating cases of the avian influenza virus in 2011 (that killed a large number of harbor seals), researchers from Columbia University’s Mailman School of Public Health analysed the animals for further viral discoveries that could occur in parallel to the influenza infection. They looked into various organs from harbor seals like lungs, liver, spleen, and oral mucosae, identifying a novel virus (phopivirus) similar to human HAV.

Genetic tests confirmed that the phopivirus has a number of similar characteristics to the HAV, which means both of these viruses have a common ancestry. This discovery may provide new information on the origin as well as pathogenicity of HAV.

These results raise the question of whether hepatitis A first originated in animals, humans or a third unrelated host. In other words, the history of HAV evolution might be more complex than previously documented. The authors suggest that further research should reveal if the phopivirus found in harbor seals is also present in other animal species, along with its ways of transmission to understand if this virus can be transmitted to humans by simply feeding on seal meat or if it requires a more complex method.