Occasionally, severe encephalitis cases occur, especially among children or the elderly. More severe infections can cause disorientation, coma, tremors, convulsions, paralysis and, rarely, death. No specific treatment for encephalitis spread by mosquitoes exists. Mosquitoes contract the encephalitis-causing viruses mainly by feeding on birds. Once infected, the mosquito can transmit the virus to humans.
Horses also can contract encephalitis from mosquitoes.
The best way to protect against contracting the disease is to avoid being bitten by mosquitoes. If you must be outdoors when mosquitoes are active, wear a long-sleeved shirt and long pants. DEET can be poisonous if overused. Never use DEET on infants. Avoid using repellents with DEET concentrations above 10 percent to 15 percent for children and with concentrations above 30 percent to 35 percent for adults.