Vincent, Alan, Dickson, and Rich talk about treating arthritis with a tanapox virus protein, Darwinian evolution of prions in cell culture, and the connection between cold weather fronts and outbreaks of avian H5N1 influenza in Europe.

Vincent, Alan, and Rich revisit circovirus contamination of Rotarix, then discuss poxvirus-like replication of mimivirus in the cell cytoplasm, and whether seasonal influenza immunization increases the risk of infection with the 2009 H1N1 pandemic virus.

Vincent, Alan, and Matt review contamination of Rotarix with circovirus DNA, antigenic similarity between 1918 and 2009 H1N1 influenza, a collection of rabies reports, and chicken pox mistaken for smallpox in Uganda.

Vincent, Dickson, and Rich discuss multipotent progenitor bone marrow cells as a reservoir of HIV-1, integration of HHV-6 into telomeres, and dispersal of West Nile virus across the US by mosquitoes.

This week the TWiV team explains CRISPR/Cas, the immune system of bacteria and archaea, how novel viruses are discovered by deep sequencing of small RNAs, and the relationship between dry weather and outbreaks of West Nile virus infection.

Vincent, Dickson, Alan, and Rich answer listener questions about maternal infection and fetal injury, viral gene therapy, eyeglasses and influenza, filtering prions from blood, eradication of rinderpest, Tamiflu resistance of H1N1 influenza, bacteriophages and the human microbiome, H1N1 vaccine recalls, human tumor viruses, RNA interference, and junk DNA.

Vincent, Dickson, and Alan consider a broad spectrum antiviral against enveloped viruses, how a plant virus induces chemical signals in the host to maximize its spread, a new way to preserve viral vaccines at tropical temperatures, and the continuing story of XMRV and chronic fatigue syndrome.

Vincent, Alan, and Rich review recent outbreaks of mumps in the UK, US, and Israel, protection of mice against 2009 H1N1 influenza A virus by 1918-like and classical swine H1N1 vaccines, and a virus-like particle vaccine for chikungunya virus.