Groundhogs help virologists more than meteorologists

Groundhogs in meteorology may not be very scientific, but in virology, the scientific merit of using groundhogs is quite sound.  They’ve become the perfect animal model to study hepatitis B and how it might be better detected and treated in humans. These groundhogs did not need to be genetically engineered in the lab like many animal models for human diseases. In nature they get infected by the woodchuck hepatitis virus. [Groundhog or woodchuck are different names for the same animal, with the scientific name, Marmota monax.]

Woodchuck hepatitis virus (WHV) is very similar to hepatitis B (HBV) that humans can catch from blood transfusions, unprotected sex, sharing needles or getting a tattoo. Both humans and groundhogs infections cause similar immune responses and can lead to the liver diseases like hepatitis and hepatocellular carcinoma.

Hepatitis research using the woodchuck all began after woodchucks started getting hepatitis and liver cancer at the Philadelphia Zoological Garden. Since WHV is so similar to HBV, investigations into the way woodchucks pass on WHV are helping scientists understand how people that have recovered from HPB infections can harbour tiny amounts of virus hiding in the cells of the liver or the immune system, allowing the disease to be reactivated when a person is immunosuppressed or on certain medications.

An acute HPV infection can be identified by probing a blood sample for a protein that HPV ‘wears’ on its surface, called a surface antigen. In the case of the hidden or occult form of the infection, the protein parts of the virus are not detectible. An occult HPV infection needs very sensitive tests to identify the HPV DNA that is found at very low levels.

How we can better detect occult HBV, eradicate it and prevent it from reactivating are problems groundhogs will help us solve. Researchers at Memorial University in Newfoundland who are using the woodchuck model to study hepatitis B say the model “has been acknowledged as the most appropriate model of HBV infection and HBV-induced liver disease, even surpassing other currently available natural and transgenic animal models.”

Mulrooney-Cousins, P.M. and Michalak, T.I. (2015) Asymptomatic Hepadnaviral Persistence and Its Consequences in the Woodchuck Model of Occult Hepatitis B Virus Infection. Journal of Clinical and Translational Hepatology 3: 211-219.

Groundhog Image: By Ladycamera - Own work, CC BY-SA 4.0, $3