Common causes of viral meningitis

Viruses are the most common cause of meningitis around the world. Meningitis is the swelling of the lining of the brain and spinal cord (called meninges), which increases pressure on the brain and causes the symptoms of meningitis.

Here we explain more about the types of viruses that may lead to meningitis.

Read more about the symptoms, treatment and after-effects of viral meningitis.

Meningitis from enteroviruses

Enteroviruses cause more than 90% of all viral meningitis cases. The two most common enteroviruses are echovirus and coxsackievirus.

Enteroviral infections are very common across the world, but most infections produce either no symptoms at all, or mild cold and flu-like symptoms. Some infections can cause stomach upsets and diarrhoea. Enteroviruses also cause both polio and hand, foot and mouth disease.

The viruses are usually passed on through contact with secretions from an infected person. This is usually from faecal-oral contamination, and less commonly from respiratory secretions. Good hand hygiene can help with prevention.

Enteroviruses are usually around during summer and autumn months in temperate climates. They mainly affect children, who are the main transmitters of these viruses.

Meningitis from parechoviruses

Parechoviruses are common across the world and mainly affect young children. They commonly cause mild stomach bugs or cold-like symptoms. They can cause more severe disease such as neonatal sepsis and meningitis, especially in young babies.

 

Meningitis from herpes viruses

Herpes simplex virus and varicella zoster virus are the most likely herpes viruses to cause meningitis.

Herpes simplex virus

Herpes simplex virus (HSV) can cause meningitis or encephalitis (inflammation of the brain), but more often causes cold sores and genital warts. This virus is very common. In fact, nearly everyone (70% by age 25 in the UK) will catch HSV sooner or later.

HSV is a common cause of viral meningitis in adolescents and adults in developed countries.

HSV viruses have been linked to a type of meningitis that can recur, commonly known as Mollaret’s meningitis. This causes sudden attacks of meningitis symptoms that usually last for two to seven days, separated by symptom-free intervals that can last for weeks, months or years.

Varicella zoster virus

Varicella zoster virus (VZV) causes chickenpox and shingles. Meningitis from VZV can occur at the same time as an episode of chickenpox or shingles, or it can occur in its own without any rash or skin symptoms.

Meningitis from mumps and measles

Mumps and measles can also cause meningitis and encephalitis (inflammation of the brain).
The mumps, measles and rubella (MMR) vaccine is available worldwide and protects against these viruses. Before the MMR vaccine was available, mumps was the most common cause of viral meningitis in the UK and occurred in 15% of patients with mumps.

It’s important to take up the vaccines available to you to protect against illness.

Meningitis from arboviruses

Arboviruses are usually transmitted by mosquitos and ticks. Some of these viruses can cause meningitis or encephalitis (inflammation of the brain) in humans. 

West Nile Virus

West Nile Virus (WNV) is carried and passed to humans by mosquitoes, and has been found in every continent except Antarctica (although it isn’t present in every country). The largest WNV outbreaks have occurred in Greece, Israel, Romania, Russia and the USA.

80% of WNV infections don’t cause any symptoms, or present as a very mild flu-like illness. Around one in 150 cases can progress to meningitis, encephalitis or lead to weakness of the limbs. These severe cases of disease can be fatal and result in long-term problems such as movement disorders and cognitive problems. 

Japanese encephalitis virus

Japanese encephalitis virus is found in pigs and birds, and is transmitted to people from mosquitoes that have bitten an infected animal. It's most common in rural areas in southeast Asia, the Pacific islands and the Far East.

Most people infected with Japanese encephalitis virus will have no symptoms or just mild flu-like illness. Around one in every 250 people who become infected with Japanese encephalitis virus develop encephalitis if the infection spreads to the brain. The virus can also cause meningitis.

Up to one in every three people who develop encephalitis will die. For those who survive, it can take several months to make a full recovery, and up to half of survivors are left with permanent brain damage.

Tick-borne encephalitis (TBE) virus

Tick-borne encephalitis (TBE) virus is transmitted to people by a tick bite. It's most common in Russia and Eastern and Central Europe.

Most people infected with TBE virus will have no symptoms at all, or will develop symptoms of a mild flu-like illness about a week after being bitten. However, a small number of people will go on to develop encephalitis or meningitis if the infection spreads to the brain. 

The best way to protect yourself from this infection is to avoid bites. You can do this by:
 

• Checking your clothes and skin for ticks regularly when walking outside.
• Walking on defined paths.
• Using insect repellent.
• Wearing long-sleeved tops and trousers when out walking.

Other arboviral causes of meningitis²

• Pawassan virus.
• Chikungunya virus.
• Dengue virus.
• Zika virus.
• Eastern equine encephalitis virus.
• Lacrosse virus.
• Jamestown canyon virus.
• Toscana virus.

The risk of being infected with certain types of arboviruses is different depending on which country you live in. 

Certain vaccinations may be recommended if you’re travelling to a country where the risk might be higher. If you’re in the UK, you can check if you need any vaccines from the Travel Health Pro website.

Meningitis from human immunodeficiency virus (HIV)

HIV can cause meningitis during the early stages of infection. Although HIV is a rare cause of viral meningitis, it’s important that adults with viral meningitis without a known cause have an HIV test. Viral meningitis may be the first sign of infection with HIV.

If not identified at this early stage, HIV can remain symptomless and undiagnosed until the individual has advanced disease or AIDS. Screening viral meningitis cases can identify more individuals with HIV, who can get early treatment and better outcomes.

Meningitis from lymphocytic choriomeningitis virus

Mice are carriers of lymphocytic choriomeningitis virus (LCMV). LCMV is passed to humans if they come into contact with urine, faeces or saliva from an infected animal.

LCMV has been detected in Europe, the Americas, Australia and Japan. It’s estimated that around 5% of house mice in the US carry the virus.

Meningitis caused by LCMV is rare and is estimated to be fatal in 1% of cases.

Learn more about meningitis

• Understand the symptoms of meningitis.
• Read about recovery from meningitis and its after-effects.
• Learn about the risk factors for meningitis.

Author: Meningitis Research Foundation.
Reviewed by: Dianne Spalding, Meningitis Research Foundation Ambassador; Dr Jeannière Manegabe, CoMO member.
Published: 3 January 2025.