Viruses Cause Brain Injuries: Prevention is the Best Strategy

Most of us don’t think about the risks of viruses attacking the brain because it’s typical for other systems in the body, like the respiratory and gastrointestinal systems or the skin, to be attacked by viruses. But many viruses attack the brain, too, causing severe inflammation of the brain and spinal cord. Anti-viral treatments may be unavailable or ineffective.

Preventive measures (especially vaccination, if available) are the best strategies. Our public health systems, and therefore our entire US population, are now threatened by government misinformation and vaccine policy changes, so there is a resurgence of these diseases.

How Do Viruses Damage the Brain?

Viruses, after crossing the blood-brain barrier or traveling through the nervous system, can cause inflammation of the protective lining of the brain and spinal cord (meningitis), or of the brain tissue itself (encephalitis). Meningitis and encephalitis share initial symptoms: high fever, vomiting, severe headache, and light sensitivity. Each has specific symptoms based on affected brain regions. Meningitis typically causes neck stiffness. Encephalitis can cause changes in mental status, such as confusion, personality changes, seizures, psychosis, and hallucinations.

There is also evidence that viral diseases may cause chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, multiple sclerosis, and vascular dementia. The mechanisms for these potential viral causes are not clear.

What Viruses Can Attack the Brain?

Now that we have established that viruses can attack the brain, let’s review which viruses can directly or indirectly affect brain function:

• “Childhood Viruses” (chicken pox, measles, mumps, rubella) were common causes of brain inflammation before vaccines became widely accepted. Expectant mothers who contract rubella can birth children with brain damage, microcephaly, and autism. Many viruses can cause hearing loss through nerve damage. Measles can cause encephalitis with developmental delays, seizures, and other brain disorders. Measles can also result in a rare but fatal condition called subacute sclerosing panencephalitis (SSPE), which appears after the initial infection, causing progressive mental deterioration and ultimately death.
• Coxsackieviruses and Polioviruses (enteroviruses) are the leading causes of viral meningitis worldwide. Poliovirus can attack the brainstem, affecting vital functions such as breathing, swallowing, and speaking, and can also cause encephalitis in other parts of the brain. Some polio survivors develop “brain fatigue” or “brain fog” and may show brain effects (MRI “hyperintensities”) of past infections.
• Herpes Simplex Virus (HSV) is the most common cause of sporadic, severe viral encephalitis in the US.
• Insect-Borne Viruses, such as West Nile Virus and Dengue Virus (both carried by mosquitoes), as well as Tick-Borne Viruses, can cause encephalitis. Dengue Virus can cause strokes, Guillain-Barré syndrome (a nervous system disorder with weakness), and brain hemorrhage (bleeding in the brain).
• Rabies Virus, which is spread to people through the bites of infected animals, travels to the brain through the spinal cord. It is almost always fatal once symptoms, such as fever or confusion, appear. Emergency treatment is essential after a rabid animal bites.
• Human Immunodeficiency Virus (HIV) attacks the body's immune system and can cause chronic brain inflammation and cognitive disorders including memory loss and personality changes.
• SARS-CoV-2 (COVID-19) can cause severe inflammation and provoke immune responses that result in structural changes in the brain that result in cognitive disorders. Attention, memory, and executive function deficits can persist for weeks to years.

Prevention

Prevention should always be the first line of defense for any disorder or disease. For viruses, get vaccinated whenever possible, and always keep yourself and your children up to date. Get advice from experts like pediatrician Paul Offit at Children’s Hospital in Philadelphia. Other preventative techniques include hand hygiene, surface disinfection, respiratory etiquette, and the use of masks against airborne viruses. Use insect repellants and other strategies if mosquitoes or ticks are a risk.