As I wrote in a previous post, hepatitis C virus (hep C) isn't frequently sexually transmitted (except possibly in Africa or among Men Who Have Sex With Men [MSM]) like HIV is, yet globally, there are four times as many people infected with hep C than there are with HIV. This is probably due to a combination of factors, but the major one is that hep C has most likely been spreading among humans for a LONG time, a lot longer than HIV has!
If hep C has been around for so long, why did we only discover it in 1989? And where did it originally come from? The title of this post alludes to the answer to one of these questions- hep C is a stealthy fugitive.
Hep C is so successful at spreading undetected among populations because it is stealthy from the moment it infects people. Aside from a period of illness when first infected ('acute' illness), which many people don't experience at all and is easily mistaken as a case of the flu, hep C infection is mostly asymptomatic, meaning people experience no discernable symptoms at all. So most people who become infected with hep C have no idea they have it!
Hep C is able to be so stealthy because it evades the immune system of the people who it infects. It is able to evade the immune system because it changes a little bit every time it replicates, or makes a copy of itself. Viruses like hep C replicate themselves inside the person they have infected thousands of times every day, so it's able to mutate and change itself very quickly!
If we imagine hep C as a criminal on the run, and the immune system as the police trying to catch it, then hep C would be a master of disguise. Every time the immune police have managed to get a photo of the criminal and distribute it out to all the other immune police in the area to try and catch it, hep C has changed it's appearance again, by getting a new hair do or wearing a moustache. The mutations that hep C accumulates every time it replicates itself are usually superficial, just like dying your hair. But it's enough to fool the immune police. The immune systems of some people who become infected with hep C are able to catch the virus and kill it, clearing their infection. But for most people, the virus escapes and stays permanently on the run, sometimes for decades, until their infection is finally discovered.
Because of hep C's stealthy ability to stay undetected in the people it infects for such long periods of time, it is able to spread through entire populations of people silently. After decades of infection with this virus, the liver of people who have been infected infected sustains so much damage, that many of them develop liver failure or liver cancer, both of which are almost always fatal.
The good news about hep C is that new drugs have been developed that can target and kill the virus very effectively, curing people of their infection very quickly and with limited side effects! However, because many people who are infected have no symptoms and are unaware that they are infected, finding people to give them this treatment is proving very difficult. Without getting treatment, people are at risk of transmitting the virus to others or developing long term liver damage, leading to liver failure or cancer. So being able to find the people who are infected and offering them treatment is essential to limit the damage from this stealthy fugitive!
This blog is written by Sofia Bartlett; scientist and curious human being. Her bio can be viewed here.
© Sofia Bartlett and Rogue Transmissions, 2017. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author is strictly prohibited.