However, in most cases, people infected with viruses that may cause meningitis do not actually develop meningitis.Viruses that can cause meningitis include:

Mechanism
Viral Meningitis is mostly caused by an infectious agent that has colonized somewhere in its host. People who are already in an immunocompromised state are at the highest risk of pathogen entry. Some of the most common examples of immunocompromised individuals include those with HIV, cancer, diabetes, malnutrition, certain genetic disorders, and patients on chemotherapy. Potential sites for this include the skin, respiratory tract, gastrointestinal tract, nasopharynx, and genitourinary tract. The organism invades the submucosa at these sites by invading host defenses, such as local immunity, physical barriers, and phagocytes or macrophages. After pathogen invasion, the immune system is activated. An infectious agent can enter the central nervous system and cause meningeal disease via invading the bloodstream, a retrograde neuronal pathway, or by direct contiguous spread. Immune cells and damaged endothelial cells release matrix metalloproteinases (MMPs), cytokines, and nitric oxide. MMPs and NO induce vasodilation in the cerebral vasculature. Cytokines induce capillary wall changes in the blood brain barrier, which leads to expression of more leukocyte receptors, thus increasing white blood cell binding and extravasation.The barrier that the meninges create between the brain and the bloodstream are what normally protect the brain from the bodys immune system. Damage to the meninges and endothelial cells increases cytotoxic reactive oxygen species production, which damages pathogens as well as nearby cells.
The authors of a study on the bubonic plague in Oran stress that the disease "is primarily a bacterial zoonosis affecting rodents. It is caused by Yersinia pestis and is transmitted from animal to animal by fleas. Humans usually become infected through the bite of an infected rodent flea." The sanitary control measure instituted by the public health authority was chemical in nature: "Intra- and peridomestic spraying with permethrin was conducted. Deltamethrin was dusted on the tracks and around the burrows of rodents located in a radius of 10 km around the dwelling of the patients. Uncontrolled killing of rats was prohibited. "A large proportion of viral pathogens that have emerged recently in humans are considered to have originated from various animal species. This is shown by several recent epidemics such as, avian flu, Ebola, monkeypox, and Hanta viruses. There is evidence to suggest that some diseases can potentially be re-introduced to human populations through animal hosts after they have been eradicated in humans. There is a risk of this phenomenon occurring with morbilliviruses as they can readily cross species barriers. CST can also have a significant effect on produce industries. Genotype VI-Avian paramyxovirus serotype 1 (GVI-PMV1) is a virus that arose through cross-species transmission events from Galliformes (i.e. chicken) to Columbiformes, and has become prevalent in the poultry industry.CST of rabies virus variants between many different species populations is a major concern of wildlife management.