The JC virus – common, harmless and sometimes, deadly

The JC virus is one of those viruses that you’ll probably never hear about, until you find it that it might kill you!

The JC virus was identified in 1965, and later named after the man whose brain it was found in, John Cunningham. It turns out that JCV is a very common virus, and it’s estimated that somewhere between 70 and 90 percent of people in the world have it, according to the World Journal of Neuroscience.

It’s not known how it spreads, but it’s thought that many people pick up JCV as children, by consuming food or water that has the virus in it. JCV can settle in your urinary tract, bone marrow, tonsils, or brain, and can stay there in a latent state for years, kept in check by your immune system.

The good news is that the average person carrying the JC virus will never know they’ve got it, and is unlikely to experience any side effects. The bad news is that in some cases the JC virus can cause a serious brain infection and kill you.

Those most at risk are people with a weakened immune system or those who are taking immunosuppressent drugs. This includes people with HIV/AIDS, multiple sclerosis (MS), rheumatoid arthritis, and certain cancers – Hodgkin’s disease, leukemia, and lymphoma. Organ transplant recipients are another high risk group, because of the drugs they take to prevent transplant rejection.

In these situations, the latent JC virus can be activated and carried through the blood-brain barrier into the brain. Here it attacks the cells responsible for making myelin, the sheath that covers and protects nerve cells. This infection is called progressive multifocal leukoencephalopathy (PML). PML is incurable and can have severe physical effects, including dementia, blindness, paralysis, and seizures. For 30–50% of people who are diagnosed with PML the condition is fatal within the first few months after diagnosis.

The grim reality of the JC virus is that it further adds to the suffering of people who are already dealing with a significant illness, and causes them to live in daily fear. Some even decide they don’t want to take the medications they need, as they don’t want to risk triggering PML.

Sadly, JC virus is one of more than 200 viruses for which there is currently no antiviral remedy.