Encephalitis

Encephalitis means inflammation of the brain. The disease usually starts with fever and confusion, and patients may lapse into coma. It is often associated with high morbidity and mortality. There are many causes of encephalitis, including infection with a virus, bacteria, parasite or fungus, metabolic disturbances, side effect of certain drugs and the symptom of a malignancy. The most common known cause of encephalitis is infection by a virus; however, it has been consistently demonstrated globally that the vast majority of cases remain unexplained.

Image: Herpes simplex virus particles

The Health Protection Agency collects some information on encephalitis through different routes. Firstly, the disease is notifiable by law. Secondly, the HPA collects laboratory reports of specific infections, such as enteroviruses, in the central nervous system through laboratory surveillance. Finally, the HPA has some special surveillance systems for infections such as measles and mumps which cause encephalitis.