Meningitis and its various types

In response to the recent multi-state outbreak of fungal meningitis, the Huron County General Health District is sharing information about the various types of meningitis.

Meningitis is caused by the inflammation of the meninges, the protective membranes that cover the brain and spinal cord.

Meningitis usually develops in response to bacteria or viruses but it can be caused by physical injury, cancer or certain drugs.

According to the Centers for Disease Control and Prevention (CDC), there are five types of meningitis: bacterial, viral, parasitic, fungal and non-infectious meningitis.

The current outbreak of fungal meningitis is not transferable person to person.

It has been traced to tainted steroid injections produced at a Massachusetts pharmacy and linked to a common fungus usually found in soil and on plants and grasses.

Nationally, the toll from the fungal meningitis outbreak is 21 dead and 247 sickened.

Here are descriptions of the five types of meningitis:

Fungal Meningitis

Fungal meningitis is rare and is usually the result of the spread of a fungus through the blood to the spinal cord. Fungal meningitis is not contagious meaning it is not transmitted from person to person. It develops after a fungus is spread through the bloodstream.

The various types of fungus that cause fungal meningitis can enter the body in different ways. Some fungi are acquired through inhaling fungal spores from soil contaminated with bird or bat droppings, or decaying organic matter. The fungi Candida is usually acquired in a hospital setting.

In the current multi-state fungal meningitis outbreak, patients are believed to have acquired the fungus through an epidural steroid injection.

Symptoms of fungal meningitis are similar to those of bacterial meningitis.

Bacterial Meningitis

In the United States from 2003 to 2007, there were about 4,100 cases of bacterial meningitis per year. Bacterial meningitis is normally severe and can cause serious complications including brain damage, hearing loss, learning disabilities or death. About 1 in 10 people with bacterial meningitis die from the disease. It can be caused by several different types of germs. Bacterial meningitis can be transmitted through respiratory and throat secretions such as kissing. Certain strains of bacterial meningitis can also be transmitted by eating contaminated food.

Factors that increase the risk for contracting bacterial meningitis include:

n Age: Infants are at a higher risk

n Community settings: Infectious diseases spread more quickly in community settings such as college dormitories

n Certain medical conditions: Conditions that weaken the immune system increase the risk of meningitis

n Travel: Sub-Saharan Africa is considered a meningitis belt and travelers there, especially during the dry season, are at a greater risk

Symptoms include a sudden onset of fever, headache and a stiff neck, as well as nausea, vomiting, confusion and sensitivity to light. Bacterial meningitis can be treated with antibiotics. Quick and appropriate treatment can reduce the risk of death from bacterial meningitis to below 15%.

The meningitis vaccine can prevent several of the various forms of bacterial meningitis. The meningitis vaccine is available at the Huron County General Health District (HCGHD). According to Chris Cherry, Director of Nursing at the HCGHD, the meningitis vaccine is recommended for people ages 11 to 55. If the vaccine is received before age 15, a booster should be given again after five years. Cherry emphasizes that the meningitis vaccine is only effective against some types of bacterial meningitis and will not prevent fungal or other types of meningitis.

Viral Meningitis

Viral meningitis is usually less severe and resolves without specific treatment. It is caused by enteroviruses and viral infections such as mumps, herpesvirus, herpes simplex viruses, varicella-zoster viruses, measles and influenza. It can also be caused by viruses spread through mosquitoes, insects and rodents.

Viral meningitis occurs most often in children younger than age 5 and those with weakened immune systems. The symptoms of viral meningitis are the same as those of bacterial meningitis. The viral form does not require treatment as viruses cannot be treated by antibiotics. However since the symptoms are the same as bacterial meningitis, which can be fatal, it is important to see a physician if experiencing any symptoms.

Parasitic Meningitis

Parasitic meningitis, sometimes referred to as PAM, for primary amebic meningoencephalitis, is a very rare form of meningitis that causes a fatal brain infection. It is caused by a parasite that enters the person's nose and travels up to the brain where it destroys the brain tissue. It is typically contracted by swimming in warm freshwater places such as lakes and rivers. It can also occur from other instances where water enters the nose such as during sinus irrigation or religious practices that submerge the head underwater. It cannot be transmitted by drinking water.

Early symptoms of parasitic meningitis are similar to those of bacterial meningitis. The disease usually causes death within 1-12 days. Almost all infections have been fatal.

Non-Infectious Meningitis

Non-infectious meningitis can be caused by cancers, lupus, head injuries, brain surgery and certain drugs. Its symptoms present the same way as those of bacterial meningitis.

For more information on meningitis, visit the CDC's website at www.cdc.gov.