Molluscum contagiosum virus (MCV) is a human poxvirus that causes asymptomatic cutaneous neoplasms that can persist for months to years in the skin of healthy or immunodeficient individuals, particularly children. Persistent infections with this virus are increasing and have become troublesome complications for adults with AIDS. At present there is no specific preventive or treatment for the disease. All attempts to culture the virus have failed and little is known about it. The objectives of the project are to analyze the structure of the viral genome, identify its genes, determine its mode of expression and replication, and find potential therapeutic targets. The way the virus resists the human immune system is of particular interest. The entire 190,000 base pair genome of MCV type I, except for terminal loops, has been sequenced. An analysis revealed that MCV encodes approximately 182 proteins, 105 of which have direct counterparts in vaccinia or smallpox virus. The latter include all genes known to be essential for replication of vaccinia virus. The unique genes include some that appear to antagonize host defenses by blocking inflammation, antigen presentation, and apoptosis.
