How Does Herpes Affect the Nervous System?

More than half of U.S. adults carry herpes simplex virus type 1 (HSV-1). Many people carrying HSV-1 never experience symptoms as the virus hibernates in the nervous system, laying dormant for long periods of time. But how does herpes affect the nervous system?

Herpes can cause everything from mild cold sores and genital blisters to life-threatening encephalitis and blindness. Understanding how various herpes infections affect the nervous system can help you get ahead of the long-term effects before they develop. Below, our team from Rapid STD Testing discusses everything you need to know about the effects of herpes infections on the nervous system. 

Unveiling Herpes' Hidden Journey Into the Nervous System

The herpes simplex virus can affect the nervous system in several ways; that said, it's important to understand the difference between HSV-1 and HSV-2 to understand how. HSV-2 is the strain of herpes commonly associated with genital sores. HSV-1, on the other hand, typically causes sores around the mouth and oral region.

While HSV-1 and HSV-2 can each be spread to both regions, HSV-1 isn’t typically considered a sexually transmitted disease while HSV-2 is. Because HSV-1 commonly affects regions near the head and brain, it can infiltrate the nervous system. 

After coming in contact with HSV-1, the virus infects the epithelial cells, which are some of the most abundant cells covering blood vessels, skin, and numerous body cavities. After infecting epithelial cells, HSV-1 infiltrates the nervous system by infecting the neurons of the peripheral nervous system (PNS). The latent neuronal infection can reactivate at random points in your life, causing you to re-experience herpes symptoms. 

HSV has a fascinating ability to enter what’s called a quiescent state, where it establishes a lifelong latent infection on its host within the sensory neurons. Latent infections typically form at the reservoir of the infection site, where you can continue transmitting the virus to others. 

Herpes uses viral replication mechanisms to enter and spread within the nervous system, all while remaining latent in neurons. Essentially, HSV-1 begins by affecting neurons closest to the initial site of the infection by stealing proteins from the epithelial cells and turning them into infectors that can spread into the PNS. Once the nervous system infection has begun, herpes can spread throughout the nervous system, potentially reaching the brain and causing herpes simplex encephalitis (HSE), neuronal damage similar to neurodegenerative diseases like Alzheimer’s disease, and more. 

In 2021, Northwestern Medicine published a case study uncovering HSV-1 viral assimilation with the hopes of tracking how herpes enters the nervous system for further vaccine development. The study discovered the first virus repurposing cellular proteins for the purpose of infecting the culprit subsequent times. With these key findings, we’re one step closer to a herpes vaccine. 

The Link Between Herpes Infections and Neurodegenerative Diseases

“How does herpes affect the nervous system?” isn't the only question someone may ask. More concerningly, can herpes virus infections lead to neurodegenerative diseases?

In general, neurodegenerative diseases include any conditions where the peripheral nervous system or brain cells lose function over time. As this occurs, you can experience memory loss, mood changes, loss of function, mobility issues, apathy, and more. Some of the top examples of neurodegenerative diseases include Alzheimer's disease and Parkinson's disease. 

Because HSV-1 takes over cells in the peripheral nervous system, it's clear that herpes might be able to affect the nervous system. What isn’t clear, though, is whether or not viral assimilation will cause you to develop neurodegenerative diseases. Remember that HSV-1 is typically a latent infection, meaning it spreads throughout the nervous system but doesn’t necessarily “kill” the neurons. 

One clinical study found that 81% of elderly Alzheimer’s disease brain patients in the study had latency-associated HSV-1, while 47% of healthy-aged people also had the same. Such results show that herpes could contribute to neurodegenerative decline, though nearly half of the participants with HIV-1 reached old age without issues. The results could show a correlation concern rather than causation, considering the large population of people who simply just live with HSV. 

While HSV may be found more frequently in Alzheimer’s disease patient brains than in healthy controls, that doesn’t necessarily mean it causes the disease. Another study on the same topic concluded that latent HSV-1 is associated with subtle cognitive disturbances but not enough cognitive decline to directly cause conditions like dementia. 

If HSV-1 infects you, one of two things can occur. The most common scenario would be that the virus establishes latency, causing minimal long-term effects. Some argue that even latent infections can result in acute and long-term damage, though. 

According to a recent research study, a few reasons that HSV-1 may harm the brain and potentially cause neurodegenerative diseases in both asymptomatic and symptomatic patients include the virus’s ability to: 

• Adjust apoptosis-related pathways, essentially programming cell death
• Distort autophagy-related processes, inhibiting numerous functions, causing the cell to degrade
• Inhibit mitochondrial dysfunction, reducing cell energy
• Induce oxidative stress, causing cell destruction
• Alter DNA damage responses, preventing cell repairs

The above theories are somewhat debated in the scientific community, as most neurodegenerative disease cases seem to be linked with symptomatic patients who experienced neuroinflammation, which brings us to the second potential outcome.  

In rare cases, the virus triggers an acute inflammatory response upon infiltrating the nervous system. This neuroinflammation causes herpes simplex encephalitis. Long-term neuroinflammation also induces oxidative stress, which can contribute to the development of neurodegenerative diseases as the inflammation can accelerate brain aging. 

Advances and Challenges in Herpes Treatment and Prevention

So, what are the latest advancements in treating and preventing herpes infections?

Antiviral therapies are the most common treatment option. Antiviral agents interfere with viral DNA, inhibiting the replication process, essentially slowing its progression and overall effects. Whether or not you require treatment will depend on the location of your infection, the severity of your symptoms (if you have any), and the frequency of the disease reactivation.

Antiviral therapies can help with symptoms of herpes but cannot cure the disease. Scientists currently have no cure for herpes because of the complexities surrounding herpes’ infiltration of the nervous system. Recognizing the different stages of herpes can help you get on antivirals as quickly as possible to mitigate symptoms before they worsen. 

The best way to avoid the complications and risks of herpes is by avoiding it entirely. You can reduce your risks of contracting herpes by avoiding physical contact with anyone who has an active breakout. 

Researchers currently have no vaccine for HSV-1 or HSV-2. Scientists continue facing hurdles when attempting to develop a vaccine as no current models have been able to perfectly replicate the virus. HSV-1 remains dormant for the large majority of its life cycle, so developing a successful vaccine involves numerous decades of testing per phase. 

There is potential for a herpes vaccine in the near future, as researchers are currently developing HSV-1 vaccines despite the numerous complications. One vaccine has reached phase II of testing and could eventually reach patients if all goes well. 

For now, you can do your best to follow safe prevention protocols and order same-day STD testing from Rapid STD Testing if you think you’ve come in contact with a virus. 

Prioritize Your Health Today

Now that you know the answer to, “How does herpes affect the nervous system?” it’s time to protect yourself and others by getting tested. With Rapid STD Testing, you can order a discreet, rapid STD test to prioritize your health. Order a 10-panel STD test from Rapid STD Testing, visit a local STD testing center, or call our team at (866) 872-1888 with any questions.