Meningitis is inflammation of the thin tissue that surrounds the brain and spinal cord, called the meninges. There are several types of meningitis. The most common is viral meningitis. You get it when a virus enters the body through the nose or mouth and travels to the brain. Bacterial meningitis is rare, but can be deadly. It usually starts with bacteria that cause a cold-like infection. It can cause stroke, hearing loss, and brain damage. It can also harm other organs. Pneumococcal infections and meningococcal infections are the most common causes of bacterial meningitis.

Anyone can get meningitis, but it is more common in people with weak immune systems. Meningitis can get serious very quickly. You should get medical care right away if you have

• A sudden high fever
• A severe headache
• A stiff neck
• Nausea or vomiting

Early treatment can help prevent serious problems, including death. Tests to diagnose meningitis include blood tests, imaging tests, and a spinal tap to test cerebrospinal fluid. Antibiotics can treat bacterial meningitis. Antiviral medicines may help some types of viral meningitis. Other medicines can help treat symptoms.

There are vaccines to prevent some of the bacterial infections that cause meningitis.

Meningitis is an infection of the meninges, the membranes that surround the brain and spinal cord. Infections and other disorders affecting the brain and spinal cord can activate the immune system, which leads to inflammation. This inflammation can produce a wide range of symptoms and, in extreme cases, cause brain damage, stroke, or even death.

When you get sick, some germs can attack the brain or the protective lining that surrounds the brain. This can cause swelling and lead to severe illness, or even death. It’s important to recognize the symptoms so you can get medical help as quickly as possible.

When the brain swells, it’s called encephalitis. When the lining of the brain, or meninges, becomes inflamed, it’s called meningitis. The symptoms can be similar for both.

At first, you might get a fever, feel tired, and sometimes have a rash. “Those things can last a day or two, or a little bit longer,” explains Dr. Avindra Nath, a neurologist at NIH. “Then, you may have a headache, along with fever, neck stiffness, and you can get sensitivity to light.”

Other symptoms include nausea or vomiting, double vision, drowsiness, and confusion. More severe illnesses can cause speech, hearing, or vision problems. If it’s left untreated, you could develop cognitive difficulties with progressive loss of consciousness, seizures, or muscle weakness.

You need to get immediate medical help if you have symptoms of encephalitis or meningitis. Early treatment is important for the best recovery. Treatment will depend on the cause. Viruses, bacteria, parasites, and fungi can all cause encephalitis and meningitis. The most common causes can be different depending on where you live.

“Worldwide, the most common cause of meningitis is bacterial meningitis,” Nath explains. “Now in the United States, we don’t see a lot of bacterial meningitis because we have certain vaccines. So, the most common cause of meningitis is viral meningitis.”

Early treatment for bacterial causes may be antibiotics and other medicines to treat swelling and other symptoms of the illness. There aren’t any specific anti-viral treatments for most viral causes. But treating the symptoms can affect the course of the illness. More severe illnesses may require hospitalization.

Anyone can get these conditions. Protecting yourself and your family from germs and staying up-to-date on vaccines is the best way to guard against both encephalitis and meningitis. Vaccines are available to prevent some bacterial causes of meningitis, including Haemophilus influenzae, pneumococcal pneumonia, and meningococcal disease.

NIH-funded researchers are looking for other ways to prevent or treat encephalitis and meningitis. Some are studying how to stop germs from infecting the brain or its lining.

Nath’s team is testing compounds that may block Zika virus from getting into brain cells grown in the lab. His team hopes that these may block other viruses that are transmitted by insects and parasites, too.

Many scientists are trying to develop broad antivirals, Nath says. “Broad” means the antiviral would stop many viruses rather than just one. This would be helpful, since doctors wouldn’t have to know which virus is causing the problem before starting treatment.

Until we have better treatments, prevention is still the best medicine. Children, older adults, and those with weakened immune systems are most at risk for infections. See the Wise Choices box for tips on protecting yourself and your family.

Guard Against Meningitis and Encephalitis

• Wash your hands with soap and water often.
• Avoid people who are coughing or showing other signs of sickness.
• Stay up-to-date on your vaccines.
• Protect yourself from mosquito and tick bites. Use insect repellents and wear full-sleeve shirts and pants when you’re outside. Keep insects out of your home. Use screens on windows and doors or use air conditioning instead. Empty all standing water from your yard.

Meningitis is an inflammation (swelling) of the protective membranes covering the brain and spinal cord. A bacterial or viral infection of the fluid surrounding the brain and spinal cord usually causes the swelling. However, injuries, cancer, certain drugs, and other types of infections also can cause meningitis. It is important to know the specific cause of meningitis because the treatment differs depending on the cause.

Bacterial Meningitis

Meningitis caused by bacteria can be deadly and requires immediate medical attention. Vaccines are available to help protect against some kinds of bacterial meningitis.

Viral Meningitis

Meningitis caused by viruses is serious but often is less severe than bacterial meningitis. People with normal immune systems who get viral meningitis usually get better on their own. There are vaccines to prevent some kinds of viral meningitis.

Fungal Meningitis

Meningitis caused by fungi is rare, but people can get it by inhaling fungal spores from the environment. People with certain medical conditions, like diabetes, cancer, or HIV, are at higher risk of fungal meningitis.

Parasitic Meningitis

Various parasites can cause meningitis or can affect the brain or nervous system in other ways. Overall, parasitic meningitis is much less common than viral and bacterial meningitis.

Amebic Meningitis

Primary amebic meningoencephalitis (PAM) is a rare and devastating infection of the brain caused by Naegleria fowleri. Naegleria fowleri is a free-living microscopic ameba that lives in warm water and soil.

Meningitis Versus Meningococcal Disease: There IS a Difference

Having meningitis doesn’t always mean you have meningococcal disease. And having meningococcal disease doesn’t necessarily mean you have meningitis. Meningococcal disease is any illness caused by a type of bacteria called Neisseria meningitidis. These illnesses are serious and include meningitis and bloodstream infections (septicemia).

How it Spreads

Bacterial Meningitis

Generally, the germs that cause bacterial meningitis spread from one person to another. Certain germs can spread through food. How people spread the germs often depends on the type of bacteria. Read about common examples of how people spread the different types of bacteria to each other.

Viral Meningitis

People can spread the viruses that cause viral meningitis to other people. If you have close contact with someone who has viral meningitis, they may spread the virus to you. However, you are not likely to develop meningitis. That’s because most people infected with these viruses will not develop meningitis.

Causes

Primary amebic meningoencephalitis (PAM) is a rare brain infection that is caused by Naegleria fowleri and is usually fatal. Naegleria fowleri is a free-living ameba* (a single-celled living organism that is too small to be seen without a microscope). From 1962 to 2021, 154 U.S. infections have been reported to CDC, with an average of 2–3 per year. There have only been four U.S. survivors.

Sources of Infection and Risk Factors

Naegleria fowleri lives in warm fresh water and soil around the world, and infects people when the ameba enters the body through the nose. It grows best at higher temperatures up to 115°F (46°C) and can survive for short periods at higher temperatures.The ameba can be found in:

• Warm fresh water, such as lakes and rivers
• Geothermal (naturally hot) water, such as hot springs
• Warm water discharge from industrial or power plants
• Untreated geothermal (naturally hot) drinking water sources
• Swimming pools, splash pads, surf parks, or other recreational venues that are poorly maintained or minimally chlorinated
• Tap water
• Water heaters
• Soil

Naegleria fowleri does not live in salt water, like the ocean.

In the United States, most infections have been linked to swimming in southern states, like Florida and Texas. However, the geographical areas where Naegleria fowleri infections occur in the United States are changing. Evidence suggests that the range of Naegleriafowleri is expanding northward as the climate warms.

Although most Naegleria infections occur after people swim or submerge their heads underwater, PAM may also occur when people cleanse their noses during religious practices or irrigate their sinuses (sending water up the nose) using contaminated tap water.

How it Spreads

Naegleria fowleri infects people by entering the body through the nose, usually while swimming. The ameba travels up the nose to the brain where it destroys the brain tissue and causes swelling of the brain.

People cannot get infected with Naegleria fowleri from drinking water contaminated with Naegleria. People also do not spread the ameba or PAM to others.

Signs and Symptoms

In its early stages, symptoms of PAM are similar to symptoms of bacterial meningitis.

Symptoms of PAM start 1 to 12 days after infection.

The initial symptoms include:

• Headache
• Fever
• Nausea
• Vomiting

Later symptoms include:

• Stiff neck
• Altered mental status (confusion)
• Lack of attention to people and surroundings
• Seizures
• Hallucinations
• Coma

After the start of symptoms, the disease progresses rapidly and usually causes death within about 5 days (range 1 to 18 days).

Diagnosis

The early symptoms of PAM are similar to other more common illnesses, such as bacterial or viral meningitis. PAM is difficult to diagnose because of the rarity of the infection and the non-specific early symptoms. Doctors diagnose PAM using specific laboratory tests that are only available in a few U.S. laboratories. People should seek medical care immediately if they suddenly develop a fever, headache, stiff neck, or start vomiting, especially if they have been swimming in warm freshwater recently.

Treatment

Several drugs are effective against Naegleria fowleri in the laboratory. However, their effectiveness is unclear since almost all infections have been fatal, even when people were treated. PAM is treated with a combination of drugs that often include amphotericin B, azithromycin, fluconazole, rifampin, miltefosine, and dexamethasone. These drugs are used because they are thought to have activity against Naegleria fowleri and have been used to treat patients who survived.

Prevention

Personal actions to reduce the risk of Naegleria fowleri infection should focus on limiting the amount of water going up the nose.

Bacterial meningitis is serious. Some people with the infection die and death can occur in as little as a few hours. However, most people recover from bacterial meningitis. Those who do recover can have permanent disabilities, such as brain damage, hearing loss, and learning disabilities.

Causes

Several types of bacteria can cause meningitis. Leading causes in the United States include

• Streptococcus pneumoniae
• Group B Streptococcus
• Neisseria meningitidis
• Haemophilus influenzae
• Listeria monocytogenes
• Escherichia coli

Mycobacterium tuberculosis, which causes tuberculosis or TB, is a less common cause of bacterial meningitis (called TB meningitis).

Many of these bacteria can also be associated with another serious illness, sepsis. Sepsis is the body’s extreme response to infection. It is a life-threatening medical emergency. Sepsis happens when an infection triggers a chain reaction throughout your body. Without timely treatment, sepsis can quickly lead to tissue damage, organ failure, and death.

Some causes of bacterial meningitis are more likely to affect certain age groups:

• Newborns: Group B Streptococcus, S. pneumoniae, L. monocytogenes, E. coli
• Babies and young children: S. pneumoniae, N. meningitidis, H. influenzae, group B Streptococcus, M. tuberculosis
• Teens and young adults: N. meningitidis, S. pneumoniae
• Older adults: S. pneumoniae, N. meningitidis, H. influenzae, group B Streptococcus, L. monocytogenes

Risk Factors

Certain factors increase a person’s risk for getting bacterial meningitis. These risk factors include:

• Age: Babies are at increased risk for bacterial meningitis compared to people in other age groups. However, people of any age can develop bacterial meningitis. See section above for which bacteria more commonly affect which age groups.
• Group setting: Infectious diseases tend to spread where large groups of people gather. For example, college campuses have reported outbreaks of meningococcal disease, caused by N. meningitidis.
• Certain medical conditions: Certain medical conditions, medications, and surgical procedures put people at increased risk for meningitis. For example, having an HIV infection or a cerebrospinal fluid leak, or not having a spleen can increase a person’s risk for several types of bacterial meningitis.
• Working with meningitis-causing pathogens: Microbiologists routinely exposed to meningitis-causing bacteria are at increased risk for meningitis.
• Travel: Travelers may be at increased risk for meningococcal disease, caused by N. meningitidis, if they travel to certain places, such as:
  • The meningitis belt in sub-Saharan Africa, particularly during the dry season
  • Mecca during the annual Hajj and Umrah pilgrimage

In many countries, TB is much more common than in the United States. Travelers should avoid close contact or prolonged time with known TB patients in crowded, enclosed environments (for example, clinics, hospitals, prisons, or homeless shelters).

How It Spreads

Certain germs that cause bacterial meningitis, such as L. monocytogenes, can spread through food. But most of these germs spread from one person to another.

How people spread the germs often depends on the type of bacteria. It is also important to know that people can have these bacteria in or on their bodies without being sick. These people are “carriers.” Most carriers never become sick, but can still spread the bacteria to others.

Here are some of the most common examples of how people spread each type of bacteria to each other:

• Group B Streptococcus and E. coli: Mothers can pass these bacteria to their babies during birth.
• H. influenzae, M. tuberculosis, and S. pneumoniae: People spread these bacteria by coughing or sneezing while in close contact with others, who breathe in the bacteria.
• N. meningitidis: People spread these bacteria by sharing respiratory or throat secretions (saliva or spit). This typically occurs during close (coughing or kissing) or lengthy (living together) contact.
• E. coli: People can get these bacteria by eating food prepared by people who did not wash their hands well after using the toilet.

People usually get sick from E. coli and L. monocytogenes by eating contaminated food.

Signs and Symptoms

Meningitis symptoms include sudden onset of

• Fever
• Headache
• Stiff neck

There are often other symptoms, such as

• Nausea
• Vomiting
• Photophobia (eyes being more sensitive to light)
• Altered mental status (confusion)

Newborns and babies may not have, or it may be difficult to notice the classic symptoms listed above. Instead, babies may

• Be slow or inactive
• Be irritable
• Vomit
• Feed poorly
• Have a bulging fontanelle (the “soft spot” on a baby’s head)
• Have abnormal reflexes

If you think your baby or child has any of these symptoms, call the doctor right away.

Typically, symptoms of bacterial meningitis develop within 3 to 7 days after exposure; note, this is not true for TB meningitis, which can develop much later after exposure to the bacteria.

People with bacterial meningitis can have seizures, go into a coma, and even die. For this reason, anyone who thinks they may have meningitis should see a doctor as soon as possible.

Diagnosis

If a doctor suspects meningitis, they will collect samples of blood or cerebrospinal fluid (fluid near the spinal cord). A laboratory will test the samples to see what is causing the infection. Knowing the specific cause of meningitis helps doctors treat it.

Treatment

Doctors treat bacterial meningitis with a number of antibiotics. It is important to start treatment as soon as possible.

Prevention

Vaccination

Vaccines are the most effective way to protect against certain types of bacterial meningitis. There are vaccines for 4 types of bacteria that can cause meningitis:

• Meningococcal vaccines help protect against N. meningitidis
• Pneumococcal vaccines help protect against S. pneumoniae
• Haemophilus influenzae serotype b (Hib) vaccines help protect against Hib
• Bacille Calmette-Guérin vaccine helps protect against tuberculosis disease, but is not widely used in the United States

Make sure you and your child are vaccinated on schedule.

Like with any vaccine, these vaccines do not work 100% of the time. The vaccines also do not protect against infections from all the types (strains) of each of these bacteria. For these reasons, there is still a chance vaccinated people can develop bacterial meningitis.

Prophylaxis

When someone has bacterial meningitis, a doctor may recommend antibiotics to help prevent people around the patient from getting sick. Doctors call this prophylaxis. CDC recommends prophylaxis for:

• Close contacts of someone with meningitis caused by N. meningitidis
• Household members of someone with a serious Hib infection when the household includes one or more people at increased risk of Hib based on age, vaccination status, and/or immunocompromising conditions

Doctors or local health departments recommend who should get prophylaxis.

Healthy Pregnancy Practices

Pregnant women should talk to their doctor or midwife about getting tested for group B Streptococcus. Women receive the test when they are 36 through 37 weeks pregnant. Doctors give antibiotics (during labor) to women who test positive in order to prevent passing group B strep to their newborns.

Pregnant women can also reduce their risk of meningitis caused by L. monocytogenes. Women should avoid certain foods during pregnancy and safely prepare others.

Healthy Habits

You can also help protect yourself and others from bacterial meningitis and other health problems by maintaining healthy habits:

• Don’t smoke and avoid cigarette smoke as much as possible
• Get plenty of rest
• Avoid close contact with people who are sick
• Wash your hands often with soap and water (use hand sanitizer if soap and water aren’t available)
• Cover your mouth and nose with a tissue when you cough or sneeze (use your upper sleeve or elbow if a tissue isn’t available)

These healthy habits are especially important for people at increased risk for disease, including:

• Young babies
• Older adults
• People with weak immune systems
• People without a spleen or a spleen that doesn’t work the way it should

Causes

Fungal meningitis can develop after a fungal infection spreads from somewhere else in the body to the brain or spinal cord.

Some causes of fungal meningitis include Cryptococcus, Histoplasma, Blastomyces, Coccidioides, and Candida.

How it Spreads

Many fungi that can cause meningitis live in the environment:

• Cryptococcus lives in the environment throughout the world.
• Histoplasma lives in the environment, particularly in soil that contains large amounts of bird or bat droppings. In the United States, the fungus mainly lives in the central and eastern states.
• Blastomyces lives in moist soil and in decaying wood and leaves. In the United States, the fungus mainly lives in midwestern, south central, and southeastern states.
• Coccidioides lives in the soil in the southwestern United States, south-central Washington State, and parts of Mexico and Central and South America.

These fungi are too small to see without a microscope. People can get sick if they breathe in fungal spores. People get meningitis if the fungal infection spreads from the lungs to the brain or spinal cord. Fungal meningitis does not spread between people.

The fungus Candida can also cause meningitis. Candida normally lives inside the body and on the skin without causing any problems. However, in certain patients who are at risk, Candida can enter the bloodstream or internal organs and cause an infection.

Healthcare-Associated Fungal Meningitis

While rare, outbreaks of fungal meningitis following medical and surgical procedures have occurred.

Risk Factors

Although anyone can get fungal meningitis, people with weakened immune systems are at increased risk. Certain health conditions, medications, and surgical procedures may weaken the immune system. HIV infection and cancer are examples of health conditions that can weaken the immune system. Medications that can weaken the immune system include:

• Steroids (such as prednisone)
• Medications given after organ transplantation
• Anti-TNF (tumor necrosis factor) medications, which are sometimes given for treatment of rheumatoid arthritis or other autoimmune conditions

Premature babies with very low birth weights are also at increased risk for getting Candida bloodstream infection, which may spread to the brain.

Living in certain areas of the United States may increase the risk for fungal lung infections, which can spread to the brain or spinal cord, causing meningitis.

Signs and Symptoms

Signs and symptoms of fungal meningitis include the following:

• Fever
• Headache
• Stiff neck
• Nausea and vomiting
• Photophobia (eyes being more sensitive to light)
• Altered mental status (confusion)

Diagnosis

If a doctor suspects meningitis, he or she may collect samples of blood or cerebrospinal fluid (fluid surrounding the spinal cord). Then laboratories can perform specific tests, depending on the type of fungus suspected. Knowing the cause of fungal meningitis is important because doctors treat different types of fungal infections differently.

Treatment

Doctors treat fungal meningitis with long courses of high-dose antifungal medications, often given directly into a vein through an IV. After that, patients also need to take antifungal medications by mouth. The total length of treatment depends on the patient’s immune system and the type of fungus causing the infection. Treatment is often longer for people with weak immune systems, like those with AIDS or cancer.

Prevention

No specific activities are known to cause fungal meningitis. People with weak immune systems should

• Try to avoid areas with a lot of dust like construction or excavation sites. If you can’t avoid these areas, wear an N95 respirator (a type of face mask) while you’re there.
• Stay inside during dust storms and close your windows.
• Avoid activities that involve close contact to dirt or dust, including yard work, gardening, and digging.
• Use air filtration measures indoors.
• Clean skin injuries well with soap and water to reduce the chances of developing a skin infection, especially if the wound was exposed to dirt or dust.
• Take preventive antifungal medication if your healthcare provider says you need it.

This is especially true if they live in a geographic region where fungi like Histoplasma, Coccidioides, or Blastomyces exist.

Various parasites can cause meningitis or can affect the brain or nervous system in other ways. Overall, parasitic meningitis is much less common than viral and bacterial meningitis.

Causes

Some parasites can cause a rare form of meningitis called eosinophilic meningitis, eosinophilic meningoencephalitis, or EM.

The three main parasites that cause EM in some infected people are:

• Angiostrongylus cantonensis (neurologic angiostrongyliasis)
• Baylisascaris procyonis (baylisascariasis; neural larva migrans)
• Gnathostoma spinigerum (neurognathostomiasis)

How These Parasites Spread

These parasites normally infect animals not people. People get infected primarily by eating infected animals or contaminated foods. Please visit CDC’s websites for additional details about how these parasites spread, besides the examples listed here:

• A. cantonensis: People can get infected by eating raw or undercooked snails or slugs or contaminated produce.
• B. procyonis: People get infected by accidentally ingesting infectious parasite eggs. These eggs can be found in raccoon feces and environments (such as dirt) contaminated with raccoon feces.
• G. spinigerum: People can get infected by eating raw or undercooked freshwater fish or eels, frogs, poultry, or snakes.

Generally, people also do not spread parasitic meningitis or the parasites that cause it to other people.

People at Risk

Some people may have increased risk for infection because of where they live or travel:

• People in many parts of the world have gotten infected with A. cantonensis. Most of these infections were diagnosed in Southeast Asia and the Pacific Islands, including in Hawaii.
• B. procyonis infects raccoons throughout the United States, mainly in the Midwest, Northeast, Middle Atlantic, and West Coast. People in these areas who spend time around raccoons are at increased risk for Baylisascaris infection. In addition, young children are at risk as they may be more likely to put contaminated fingers, soil, or objects in their mouths.
• The neurologic form of G. spinigerum infection is most commonly diagnosed in Southeast Asia, particularly in Thailand, and Japan.

Signs and Symptoms

If you think that you or your child might have meningitis, see a healthcare provider right away.

As with meningitis caused by other infections, people who develop symptomatic EM from these parasites can have

• Headache
• Stiff neck
• Nausea
• Vomiting
• Photophobia (eyes being more sensitive to light)
• Altered mental status (confusion)

People with EM caused by A. cantonensis often have tingling or painful feelings in their skin and may have a low-grade fever.

All three of these parasites sometimes infect the eye(s). All three parasites, but most commonly Baylisascaris, can cause severe complications, such as

• Loss of coordination and muscle control
• Weakness/paralysis
• Coma
• Permanent disability
• Death

Diagnosis

If a doctor suspects meningitis, he or she may collect samples of blood or cerebrospinal fluid. The laboratory looks for evidence of parasitic infection and to rule out other causes. It often is hard to find these parasites in the cerebrospinal fluid or in other parts of the body. In addition to laboratory testing, the following may be helpful for making a diagnosis:

• Travel or exposure history
• Clinical examination
• Other medical tests, such as brain scans

Treatment

There is no specific treatment for EM caused by these parasites. Pain medication may be used for headaches. Medications may also be used to reduce the body’s reaction to the parasite—rather than for the infection itself. However, treatment for the infection might help some people.

Viral meningitis (when meningitis is caused by a virus) is the most common type of meningitis. Most people get better on their own without treatment. However, anyone with symptoms of meningitis should see a doctor right away because any type of meningitis can be serious. Only a doctor can determine if someone has meningitis, what is causing it, and the best treatment. Babies younger than 1 month old and people with weakened immune systems are more likely to have severe illness from viral meningitis.

Causes

Non-polio enteroviruses are the most common cause of viral meningitis in the United States. Only a small number of people infected with enteroviruses will develop meningitis.

Other viruses that can cause meningitis are

• Mumps virus
• Herpesviruses, including Epstein-Barr virus, herpes simplex viruses, and varicella-zoster virus (which causes chickenpox and shingles)
• Measles virus
• Influenza virus
• Arboviruses, such as West Nile virus
• Lymphocytic choriomeningitis virus

People at Risk

People of any age can get viral meningitis. However, some people have a higher risk of getting the disease, including:

• Children younger than 5 years old
• People with weakened immune systems caused by diseases, medications (such as chemotherapy), and recent organ or bone marrow transplantations

Babies younger than 1 month old and people with weakened immune systems are also more likely to have severe illness.

How it Spreads

Close contacts of someone with viral meningitis can become infected with the virus that made that person sick. However, these close contacts are not likely to develop meningitis. Only a small number of people who get infected with the viruses that cause meningitis will develop viral meningitis.

Viruses that can cause meningitis spread in different ways. Learn more about how the following viruses spread by visiting CDC’s websites:

• Non-polio enteroviruses
• Mumps virus
• Herpesviruses, including Epstein-Barr virus, herpes simplex viruses, and varicella-zoster virus
• Measles virus
• Influenza virus
• Arboviruses, like West Nile virus
• Lymphocytic choriomeningitis virus

Symptoms

Common symptoms in babies

• Fever
• Irritability
• Poor eating
• Sleepiness or trouble waking up from sleep
• Lethargy (a lack of energy)

Common symptoms in children and adults

• Fever
• Headache
• Stiff neck
• Photophobia (eyes being more sensitive to light)
• Sleepiness or trouble waking up from sleep
• Nausea
• Irritability
• Vomiting
• Lack of appetite
• Lethargy (a lack of energy)

Most people with mild viral meningitis usually get better on their own within 7 to 10 days.

Initial symptoms of viral meningitis are similar to those for bacterial meningitis. However, bacterial meningitis is usually severe and can cause serious complications, such as brain damage, hearing loss, or learning disabilities. The pathogens (germs) that cause bacterial meningitis can also be associated with another serious illness, sepsis. Sepsis is the body’s extreme response to infection. Without timely treatment, sepsis can quickly lead to tissue damage, organ failure, and death.

See a doctor right away if you think you or your child might have meningitis. A doctor can determine if you have the disease, what is causing it, and the best treatment.

Diagnosis

Doctors diagnose meningitis by ordering specific lab tests on specimens from a person suspected of having meningitis. If a doctor suspects meningitis, he or she may collect samples for testing by

• Swabbing your nose or throat
• Obtaining a stool sample
• Taking some blood
• Drawing fluid from around your spinal cord

Treatment

In most cases, there is no specific treatment for viral meningitis. Most people who get mild viral meningitis usually recover completely in 7 to 10 days without treatment. Antiviral medicine may help people with meningitis caused by viruses such as herpesvirus and influenza.

Antibiotics do not help viral infections, so they are not useful in the treatment of viral meningitis. However, antibiotics do fight bacteria, so they are very important when treating bacterial meningitis.

People who develop severe illness, or are at risk for developing severe illness, may need care in a hospital.

Prevention

There are no vaccines available in the United States to protect against non-polio enteroviruses, which are the most common cause of viral meningitis. The best way to help protect yourself and others from non-polio enterovirus infections is to

• Wash your hands often with soap and water for at least 20 seconds, especially after changing diapers or using the toilet
• Avoid close contact, such as touching and shaking hands, with people who are sick
• Clean and disinfect frequently touched surfaces
• Stay home when you are sick and keep sick children out of school

Vaccines can protect against some diseases, such as measles, mumps, chickenpox, and influenza, which can lead to viral meningitis. Make sure you and your child are vaccinated on schedule.

Avoid bites from mosquitoes and other insects that carry diseases that can infect humans.

Control mice and rats. If you have a rodent in or around your home, follow appropriate cleaning and control precautions.

Anyone—from infants to older adults—can get meningitis. People with weakened immune systems, including those persons with HIV or those taking immunosuppressant drugs, are at increased risk.

Some forms of bacterial meningitis are contagious and can be spread through contact with:

• Saliva
• Nasal discharge
• Feces
• Respiratory and throat secretions (often spread through kissing, coughing, or sharing drinking glasses, eating utensils, or such personal items as toothbrushes, lipstick, or cigarettes)

For example, people sharing a household, at a day care center, or in a classroom with an infected person can become infected. College students living in dormitories—in particular, college freshmen—have a higher risk of contracting meningococcal meningitis than college students overall. Children who have not been given routine vaccines are at increased risk of developing certain types of bacterial meningitis.

Because the disease can occur suddenly and progress rapidly, anyone who is suspected of having meningitis should immediately contact a doctor or go to the hospital.

Infectious causes of meningitis include bacteria, viruses, fungi, and parasites. For some individuals, environmental exposure (such as a parasite), recent travel, or an immunocompromised state (such as HIV, diabetes, steroids, chemotherapy treatment) are important risk factors. There are also non-infectious causes such as autoimmune/rheumatological diseases and certain medications.

• Bacterial meningitis is a rare but potentially fatal disease. Several types of bacteria can first cause an upper respiratory tract infection and then travel through the bloodstream to the brain. The disease can also occur when certain bacteria invade the meninges directly. Bacterial meningitis can cause stroke, hearing loss, and permanent brain damage.
  
• Pneumococcal meningitis is the most common form of meningitis and is the most serious form of bacterial meningitis. The disease is caused by the bacterium Streptococcus pneumoniae, which also causes pneumonia, blood poisoning (septicemia), and ear and sinus infections. At particular risk are children under age 2 and adults with a weakened immune system. People who have had pneumococcal meningitis often suffer neurological damage ranging from deafness to severe brain damage. Immunizations are available for certain strains of the pneumococcal bacteria.
  
• Meningococcal meningitis is caused by the bacterium Neisseria meningitides and is very contagious. High-risk groups include infants under the age of 1 year, people with suppressed immune systems, travelers to foreign countries where the disease is endemic, and college students (freshmen in particular), military recruits, and others who reside in dormitories. Between 10-15 percent of cases are fatal, with another 10-15 percent causing brain damage and other serious side effects. If meningococcal meningitis is diagnosed, people in close contact with an infected individual should be given preventative antibiotics.
  
• Haemophilus influenzae meningitis was at one time the most common form of bacterial meningitis. Fortunately, the Haemophilus influenzae b vaccine has greatly reduced the number of cases in the United States. Those most at risk of getting this disease are children in child-care settings and children who do not have access to the vaccine.

Other forms of bacterial meningitis include:

• Listeria monocytogenes meningitis (in which certain foods such as unpasteurized dairy or deli meats are sometimes implicated).
  
• Escherichia coli meningitis, which is most common in elderly adults and newborns and may be transmitted to a baby through the birth canal.
  
• Mycobacterium tuberculosis meningitis, a rare disease that occurs when the bacterium that causes tuberculosis attacks the meninges.

Viral, or aseptic, meningitis is usually caused by enteroviruses—common viruses that enter the body through the mouth and travel to the brain and surrounding tissues where they multiply. Enteroviruses are present in mucus, saliva, and feces, and can be transmitted through direct contact with an infected person or an infected object or surface. Other viruses that cause meningitis include varicella zoster (the virus that causes chicken pox and can appear decades later as shingles), influenza, mumps, HIV, and herpes simplex type 2 (genital herpes).

Fungal infections can affect the brain. The most common form of fungal meningitis is caused by the fungus cryptococcus neoformans (found mainly in dirt and bird droppings). Cryptococcal meningitis mostly occurs in immunocompromised individuals such as those with AIDS but can also occur in healthy people. Some of these cases can be slow to develop and smolder for weeks. Although treatable, fungal meningitis often recurs in nearly half of affected persons.

Parasitic causes include cysticercosis (a tapeworm infection in the brain), which is common in other parts of the world, as well as cerebral malaria.

There are rare cases of amoebic meningitis, sometimes related to freshwater swimming, which can be rapidly fatal.

The signs of meningitis may include:

• Sudden fever
• Severe headache
• Nausea or vomiting

• Double vision
• Sensitivity to bright light
• Stiffness in the neck

Meningitis often appears with flu-like symptoms that develop over one to two days. Distinctive rashes are typically seen in some forms of the disease. Meningococcal meningitis may be associated with kidney and adrenal gland failure and shock.

Important signs to watch for in an infant include fever, lethargy, not waking for feedings, vomiting, body stiffness, unexplained/unusual irritability, and a full or bulging fontanel (the soft spot on the top of the head).

Following a physical exam and medical history to review activities of the past several days or weeks (such as recent exposure to insects, ticks or animals, any contact with ill persons, or recent travel; preexisting medical conditions and medications), the doctor may order various diagnostic tests to confirm the presence of infection or inflammation. Early diagnosis is vital, as symptoms can appear suddenly and escalate to brain damage, hearing and/or speech loss, blindness, or even death.

Diagnostic tests include:

• A neurological examination involves a series of physical examination tests designed to assess motor and sensory function, nerve function, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behavior.
  
• Laboratory screening of blood, urine, and body secretions can help detect and identify brain and/or spinal cord infection and determine the presence of antibodies and foreign proteins. Such tests can also rule out metabolic conditions that may have similar symptoms.
  
• Analysis of the cerebrospinal fluid that surrounds and protects the brain and spinal cord can detect infections in the brain and/or spinal cord, acute and chronic inflammation, and other diseases. A small amount of cerebrospinal fluid is removed by a special needle that is inserted into the lower back and the fluid is tested to detect the presence of bacteria, blood, and viruses. The testing can also measure glucose levels (a low glucose level can be seen in bacterial or fungal meningitis) and white blood cells (elevated white blood cell counts are a sign of inflammation), as well as protein and antibody levels.

Brain imaging can reveal signs of brain inflammation, internal bleeding or hemorrhage, or other brain abnormalities. Two imaging procedures are routinely used to diagnose meningitis.

1. Computed tomography, also known as a CT scan
2. Magnetic resonance imaging (MRI)

Additionally, electroencephalography, or EEG, can identify abnormal brain waves by monitoring electrical activity in the brain.

People who are suspected of having meningitis should receive immediate, aggressive medical treatment. The disease can progress quickly and has the potential to cause severe, irreversible neurological damage.

Early treatment of bacterial meningitis involves antibiotics that can cross the blood-brain barrier (a lining of cells that keeps harmful micro-organisms and chemicals from entering the brain). Appropriate antibiotic treatment for most types of meningitis can greatly reduce the risk of dying from the disease. Anticonvulsants to prevent seizures and corticosteroids to reduce brain inflammation may be prescribed.

Infected sinuses may need to be drained. Corticosteroids such as prednisone may be ordered to relieve brain pressure and swelling and to prevent hearing loss that is common in Haemophilus influenza meningitis. Lyme disease is treated with antibiotics.

Antibiotics, developed to kill bacteria, are not effective against viruses. Fortunately, viral meningitis is rarely life threatening and no specific treatment is needed. Fungal meningitis is treated with intravenous antifungal medications.

People should avoid sharing food, utensils, glasses, and other objects with someone who may be exposed to or have the infection. People should wash their hands often with soap and rinse under running water.

Effective vaccines are available to prevent Haemophilus influenza, pneumococcal and meningococcal meningitis.

People who live, work, or go to school with someone who has been diagnosed with bacterial meningitis may be asked to take antibiotics for a few days as a preventive measure.

To lessen the risk of being bitten by an infected mosquito or other arthropod, people should:

• Limit outdoor activities at night
• Wear long-sleeved clothing when outdoors
• Use insect repellents that are most effective for that particular region of the country
• Rid lawn and outdoor areas of free-standing pools of water where mosquitoes like to breed

Repellants should not be overapplied, particularly on young children and especially infants, as chemicals like DEET may be absorbed through the skin.

The outlook for individuals with meningitis generally depends on the particular infectious agent involved, the severity of the illness, and how quickly treatment is given. In most cases, people with very mild meningitis can make a full recovery, although the process may be slow.

Individuals who experience only headache, fever, and stiff neck may recover in two to four weeks. Individuals with bacterial meningitis typically show some relief 48-72 hours following initial treatment but are more likely to experience complications caused by the disease. In more serious cases, the disease can cause hearing and/or speech loss, blindness, permanent brain and nerve damage, behavioral changes, cognitive disabilities, lack of muscle control, seizures, and memory loss. These individuals may need long-term therapy, medication, and supportive care.