Researchers shed light on what causes herpes simplex
virus to flare up, explaining how stress, illness
and even sunburn can trigger unwanted outbreaks. The
discovery could lead to new ways to prevent cold
sores and herpes-related eye disease from
reoccurring, the researchers report. Herpes simplex
recurrence has long been associated with stress,
fever and sunburn. Instead, it lurks inside neurons, waiting for
the right moment to strike again, a process known as
reactivation. Cold sores, also known as fever
blisters, are one of the most common symptoms of HSV
reactivation. Recurrent reactivation in the eye
leads to herpes keratitis, which, if left untreated,
can result in blindness. HSV infection has also been
linked to the progression of Alzheimer's disease.
Recurrences of HSV are typically associated with
stress, illness or sunburn, but doctors have been
uncertain exactly what causes the virus to
reactivate. The researchers determined that the
virus highjacks an important immune response within
the body. In response to prolonged periods of
inflammation or stress, the immune system releases a
particular cytokine, Interleukin 1 beta. This
cytokine is also present in epithelial cells in the
skin and eye and is released when these cells are
damaged by ultraviolet light. Interleukin 1 beta
then increases the excitability in the affected
neurons, setting the stage for HSV to flare up, the
UVA researchers discovered. The scientists say that
more research will need to be done to fully
understand the potential factors which play into
herpes simplex disease. It may vary depending on the
virus strain or the type of neuron infected, even.
And it is still unknown if the virus alters how
neurons respond to cytokines such as Interleukin 1
beta. But the new insights help doctors better
understand what is happening in neurons and the
immune system, and that could lead to ways to
prevent unwanted outbreaks, the researchers hope. |