Viral meningitis

Anyone can get viral meningitis, but it occurs most often in children. It is more common in the summer. Most cases of viral meningitis are relatively mild, with symptoms of headache, fever and general ill feeling, and those affected recover without medical treatment. This is one reason why it is so difficult to measure how many cases of viral meningitis actually occur, but we do know that it is fairly common, probably more common than bacterial meningitis.

Sometimes the disease progresses with further symptoms: nausea and vomiting, stiff neck, sore throat, abdominal pain, muscle pain, photophobia, altered consciousness. Very unusually, it can become life-threatening or cause long-term after effects.

Viral meningitis is not usually associated with septicaemia.

Although most people recover within 5 days to a fortnight, it may take more time, and for some people the recovery period is prolonged. Antibiotics are ineffective against viruses, so treatment is normally limited to easing the symptoms of the disease (for example, painkillers for headache, anti-emetics to stop vomiting).

Many different viruses can cause viral meningitis, and most people are exposed to some of them during their life without developing meningitis. The most common causes are:

• Enteroviruses (viruses that can live in the cells lining our intestines or noses and throats) account for most cases of viral meningitis. There are about eighty different types, the majority being either Coxsackie or Echovirus groups. Most enteroviral infections produce mild symptoms: sore throats, colds and flu-like illnesses. They can also cause fever with a rash, which in the early stages of diagnosis can cause confusion with meningococcal disease. They are also the cause of hand, foot and mouth disease. In very rare cases some enteroviruses can cause serious infections of the liver, heart and brain.
• Mumps and Measles viruses cause some cases of meningitis, but MMR vaccine prevents these types of meningitis. Before the vaccine was available, mumps was the most common cause of viral meningitis in the UK.
• Herpes viruses can cause meningitis or encephalitis (inflammation of the brain itself). Herpes encephalitis is rare but life-threatening. Herpes meningitis is not usually serious, but in a fifth of cases it can recur.
• Arboviruses normally affect wild animals such as birds or rodents and are carried by mosquitoes or ticks. Some arboviruses can cause meningitis or encephalitis in humans, but this is not a problem in the UK or Ireland. They cannot be passed directly between people.

In cases of viral meningitis, it is not always possible to identify the type of virus responsible for the disease.

Aside from MMR vaccination, a good general precaution against viral meningitis is attention to handwashing, since these viruses usually enter the body via the hand to mouth route. They can also be passed by respiratory contact. Viral meningitis does not normally require public health measures to be taken, because although some of the viruses that cause it are contagious, most people infected have no symptoms, or very mild symptoms.  A person with viral meningitis may pass on the virus, but this would be unlikely to cause another person to develop viral meningitis. In some countries outbreaks of viral meningitis are sometimes caused by contamination of the water supply.