New Hepatitis B Virus Discovered in White Sucker (Catostomus commersonii)

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The first known hepatitis B virus to infect fish (white sucker; Catostomus commersonii) has been discovered by U.S. Geological Survey (USGS) scientists. 

USGS scientist collecting a liver tissue sample from a wild-caught white sucker

A USGS scientist collecting a liver tissue sample from a wild-caught white sucker (Catostomus commersonii) from a river in the Great Lakes area. Photo Credit: Patricia M. Mazik, USGS.

These findings, with the full genetic sequence of the virus, were published in the Journal of Virology. This newly discovered virus is in the family Hepadnaviridae, which include similar viruses in mammals and birds. This virus is unique from other known hepadnaviruses and likely represents a new genus. In mammals, including humans, these viruses are typically associated with liver diseases including fibrosis, cirrhosis, and cancer. Human hepatitis B virus has a specific protein that is associated with cancer induction, and this tumor-associated protein is not present in the new hepatitis B virus isolated from white suckers.

White suckers inhabit river systems in the Midwestern and Northeastern United States. As bottom-feeders, they are continuously exposed to contaminants in river sediments and are used as an indicator species in assessing the health of their aquatic environments. The incidence of liver tumors in these fish has been used as an indication of toxic contaminant exposure. It is not known if this newly identified virus is associated with tumors or liver disease in these fish, but it may be a risk factor.

This research was partially funded by the USGS Contaminant Biology Program and Fisheries: Aquatic and Endangered Resources Programs, the Cooperative Research Unit Program, and the Great Lakes Restoration Initiative.

A white sucker (Catostomus commersonii)

A white sucker (Catostomus commersonii). Photo Credit: Fairfax County Government, Virginia.


Transmission electron micrographs of complete hepatitis B viral particles

Transmission electron micrographs of complete hepatitis B viral particles. The particles are approximately 40 nanometers in diameter, and in the lower right corner of the images is a 100 nanometers scale bar. Modified from figure 7 of Hahn and others, 2015. Photo Credit: James Driver, University of Montana.

This article was featured in the USGS GeoHealth Newsletter, Vol. 13, No. 1, 2016.