Long-term persistent infection of domestic rabbits by the human foamy virus

Human foamy virus (HFV) belongs to the spumaretrovirus group of the Retroviridae taxonomic family. Attempts to associate HFV or other foamy viruses to a specific pathology still remain unsuccessful. However, viral gene expression as well as tissue-specific tropism in an in vivo context remain poorly analyzed. To address this issue, we have infected domestic rabbits with a single dose of HFV and followed them at the biological and molecular levels for 5 years. No apparent pathology was detectable in the infected animals which have developed a strong immunological response against major viral proteins. We found that HFV provirus in blood cells and several organs persisted predominantly in its defective form, delta HFV, suggesting that in vivo viral persistence could be related to homologous interference as was recently shown in vitro. This animal model might be useful for studying the in vivo targets of HFV and should also be convenient for testing therapeutic effects of antiretroviral drugs.