Herpes virus kills colonic nerves, causes constipation


Why herpes infection and constipation often go hand-in-hand has been a mystery. A new study shows a possible route via the spinal cord. Amy Middleton reports.


A low-fibre diet, no exercise and dehydration can all cause constipation. Now scientists have shown how the herpes virus can attack colonic nerves, stopping food from moving through the bowel.
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Feeling a bit backed up but don't know why? Don't rule out a viral infection.

New research has found a surprising link between genital herpes and constipation, showing the virus can move to the host's spinal cord and attack nerves in the colon.

Herpes is one of the most common viral infections in the world, affecting around 650 million people worldwide. Although it can be carried silently, without ever showing symptoms, some patients suffer outbreaks of cold-sore-like blisters in affected areas.

Genital herpes, more specifically, is an infection usually caused by one of two strains of the herpes simplex virus, or HSV. The strains HSV-1 and HSV-2 can both cause genital herpes.

According to a paper, published in the journal Cell Host & Microbe, around 15% of women living with the HSV-2 strain report difficulty passing urine.

In some cases, symptoms also include pain, sensory loss, rash and constipation.

The reason for these additional symptoms remains unknown. So a research team led by Akiko Iwasaki, an immunobiologist at Yale University, set out to find the link between HSV and digestive problems.

So a research team, led by Akiko Iwasaki, professor of immunobiology at Yale University, wanted to find the link between HSV and digestive problems.

To explore this, the team used a mouse model of HSV-1. Although mice have different reactions to HSV infection than humans, some symptoms are mirrored, including urine retention and constipation.

They found in a third of infected mice, the virus travelled from the genital area to the colon via the spinal cord.

Once it reached the colon, the virus caused swelling, killed off neurons and interrupted the natural contractions that help food shuffle through the digestive tract.

There is evidence that this hypothesis applies to humans as well as mice, explains Iwasaki:. “Other members of the herpes virus family, including Epstein-Barr virus, chicken pox virus and cytomegalovirus have been found in the neurons of the colon of people with unexplained chronic constipation.

“When doctors can’t figure out the cause of these chronic intestinal conditions, one thing to look at is a viral infection.”

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  1. http://www.cell.com/cell-host-microbe/fulltext/S1931-3128(16)30204-9
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