Meningitis is inflammation of the lining of the central nervous system, often by infection. It can be transmitted as viruses, bacteria, fungi, or parasites. The most common form of the disorder is viral meningitis, which tends to resolve on its own. On the other hand, bacterial meningitis can be severe and lead to brain damage, hearing loss, or learning disabilities if not properly treated. Good hygiene is the general practice for preventing the transmission of meningitis. Vaccines are available against the common bacterial causes, including Hib and meningococcus and recommended for college students due to the close quarters they live in.
Read more about how meningitis is transmitted below the jump.
Inflammation of the meninges, the membranes lining the spinal cord and brain, is known as meningitis. Forms of the disorder that can be transmitted are caused by infection with viruses, bacteria, fungi, or parasites. According to the Centers for Disease Control (CDC), Streptococcus pneumoniae and Neisseria meningitides (meningococcal meningitis) are the most common causes of bacterial meningitis. Prior to the 1990s, Haemophilis influenzae type b (Hib) was the most common bacterial cause of meningitis. The most common form of the disorder is viral meningitis (also known as aseptic meningitis), which tends to resolve on its own. On the other hand, bacterial meningitis can be severe and lead to brain damage, hearing loss, or learning disabilities if not properly treated.
According to the CDC, the most common viruses causing meningitis in the United States are enteroviruses, which include coxsackieviruses. Infection usually occurs in the summer and autumn. These viruses are spread via fecal contamination, which can be avoided by proper hygiene, as well the respiratory secretions of infected individuals. Other viral causes appear as the complications of infection with mumps, chicken pox (varicella-zoster), measles, influenza, and herpes virus, which can be spread by contact with the saliva, mucus, or sputum of infected individuals.
Arboroviruses and West Nile virus can also cause meningitis. These viruses are spread by mosquitos and insects. Rodents can also spread meningitis by transmitting lymphocytic choriomeningitis virus, but this is rare.
Some of the bacteria that cause meningitis are contagious and can be spread via the exchange of saliva and respiratory secretions (i.e. kissing). They are not spread via indirect contact. However, meningococcal meningitis is known to spread via prolonged, close contact, such as that found in dormitories. The bacteria causing an ear or nasal infection can also occasionally spread to the brain, and untreated localized infections anywhere in the body can end up in the bloodstream (sepsis) and end up inflaming the brain.
Fungal meningitis is not contagious according to the CDC. It is transmitted by the inhalation of spores in the environment. Individuals with suppressed immune systems (such as those with chronic disease or who received transplants) are at risk of becoming infected when exposed to the spores. Cryptococcus and Histoplasma are two types of fungi that cause inflammation of the nervous system, and they are thought to be transmitted via bird droppings. Blastomyces and Coccidioides are found in the soil, with particular areas where they are endemic in the United States (Midwest and Southwest, respectively). Candida (yeast) infection can also cause meningitis if it spreads via the bloodstream.
Eosinophilic meningitis is the form most commonly causes by parasitic infection. Parasites that cause this disorder can be transmitted by consuming inadequately cooked (or raw) seafood, fish, poultry, and mollusks. Contamination with raccoon feces is also a risk factor for infection. Examples of parasites that cause meningitis are Angiostrongylus cantonensis, Baylisascaris procyonis, and Gnathostoma spinigerum, though research has identified quite a few more. Parasites can be transmitted to other people via fecal contamination and, potentially, intimate contact with an infected individual.
Good hygiene is the general practice for preventing the transmission of meningitis. Vaccines are available against the common bacterial causes, including Hib and meningococcus.