Table 2.

Unanswered questions on foamy virus research.

What will be the next example of the early origins of FVs?

What are the first cells to be infected in naïve hosts and how does FV spread within an organism before becoming latent?

What are the anatomic sites of FV latent infection and active replication in vivo?

What are mechanisms of FV persistence?

What are the in vivo mechanisms of immune control of FV?

Is there any pathogenic effect of FVs, per se or in the context of co-infection with other pathogens?

What are the distribution and the magnitude of zoonotic infection in Africa, Asia, and America?

Are there biological abnormalities and/or clinical symptoms associated with FV infection in humans?

What are the roles of restriction factors on FV replication and transmissibility in the human infected hosts?

For how long will the FV receptor remain unknown?

When will the 3D structures of all FV proteins be available?

Do FV entry and early steps of replication impact cell tropism and host–virus interaction?

What are the respective roles of FV Gag and integrase in FV integration site selection?

What are the viral and cellular factors controlling FV gene expression and recovery from latency?

What are the role of FV-encoded microRNAs?

When will the first foamy virus vector be used in a human gene therapy trial?