HSV-1 Infection Held Up in an Unsuspected Way
Research has suggested that one or two herpes viruses stop to attack skin cells before entering the body, leaving a window of opportunity to treat the disease before infection occurs during this early stage.
Proceedings of the National Academy of Sciences has published a report from researchers at Princeton University indicating that most viruses spread by throwing millions of particles at cells, but this is not the case with the HSV-1 (herpes simplex virus type 1). This virus (responsible for both genital legions and cold sores) just sends in one or two particles during the initial invasion of skin cells in order to form cold sores.
This was shocking to researchers since the disease is known to produce hundreds of particles within a cell according to Matthew Taylor who is the author of the study. What causes the hold up?
HSV-1 particles can remain dormant in a person for years after infection. The first stage of sore formation is when these cells awaken and infect nearby skin cells, beginning the process of forming a cold sore. Once this happens the virus replicates rapidly and we see the millions of copies as a visible cold sore. This is when the disease becomes transferable via skin to skin contact.
The fact that the cold sore is made up of just one or two particles initially means that when the disease is spread there is very little genetic diversity to it. This really should hurt the diseases’ ability to grow and spread since it lacks a variety of genomes. This is in sharp contrast with the way that HIV spreads with its many particles and distinct genomes. The result is that if any mutation weakens the HSV-1 virus, it becomes highly unlikely to be able to adapt and survive.
This results in two things. First, only the most fit particles survive. While that doesn’t sound positive, it also means that the disease can be targeted by specific treatment since it is not genetically diverse. Researchers in Tel Aviv are now working on drugs that can attack the disease at this vulnerable point.
Researchers are also looking into alpha-herpes viruses to see if they share the same weakness. Among these viruses are HSV-2 and the virus that causes chicken pox and shingles. Even West Nile virus and poliovirus are being looked into.
Scientists are excited to find that while the transmission of these diseases is very efficient, the means may also leave a window of opportunity for treatment.
The research was color coded in red, green, and blue using different viral genomes. Infected cells could thus be examined for particles in a particular color revealing the number of particles that had breached a cell. The method was developed in the math department in Princeton. The results showed an average of two or fewer viral genomes infecting cells.
The process was repeated with the pseudorabies virus, an alpha-herpes virus that is particular to animals. The results were the same.