Encephalitis is an uncommon viral disease in which the brain, spinal cord, and membranes covering these organs become in­flamed. Some cases of encephalitis are contracted as a result of mosquito bites

while a few are probably due to tick bites. Severe infections begin suddenly with high fever, vomiting, confusion and drowsiness. These signs are followed by stupor or coma, stiffness, tremulousness, and sometimes seizures or paralysis. Mild cases occur with no more than fever and headache for a few days, but the death rate ranges from five percent to sixty percent in severe cases. Treatment is supportive as antibiotics are not effective.