Common Causes of Viral Meningitis
Virus | Mechanism of Transmission | Seasonal Incidence |
|---|---|---|
Enteroviruses (eg, coxsackieviruses, echoviruses) | Fecal-oral spread (eg, via contaminated food, in swimming pools) | Summer to early autumn Sometimes sporadic cases throughout year |
Herpes simplex, usually virus type 2* | Close or sexual contact with a person actively shedding the virus | None |
Inhalation of respiratory droplets from or by contact with an infected person | None | |
Eastern equine encephalitis virus† Venezuelan equine virus† | Mosquito | Summer to early autumn |
Flaviviruses:
| Mosquito | Summer to early autumn |
Orthobunyaviruses:
| Mosquito | Summer to early autumn |
Powassan virus | Ticks | Late spring to early summer; mid autumn |
Colorado tick fever virus (unusual) | Ticks | Late spring to early summer |
Airborne‡ | Autumn to winter | |
Contact with body fluids of an infected person | None§ | |
* Herpes simplex type 2 meningitis may occur as an isolated instance or may recur. | ||
† Western equine and Venezuelan equine viruses have been associated with meningitis, but no cases have been reported in the United States in recent years. | ||
‡ Lymphocytic choriomeningitis virus is associated with exposure to infected wild mice (the natural host for this virus) and is most common during autumn or winter when mice tend to move indoors. Infection may also occur year-round when the cause is exposure to infected pet hamsters. | ||
§ Meningitis due to HIV usually begins early in the course of systemic infection—when seroconversion occurs. | ||