Q: What is La Crosse encephalitis?A: The La Crosse virus is spread by infected mosquitoes. Most people don’t have symptoms, but some rarely develop encephalitis, or an inflammation of the brain that can be life-threatening.Q: How many cases of La Crosse encephalitis are reported each year?A: About 80 to 100 cases are reported nationwide each year, with roughly a quarter of cases (about 20) occurring in Ohio.Q: Who’s at risk?A: Anyone who is bitten by a mosquito in an area where the virus is circulating can contract the virus.