(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) Rebecca Trout Fryxell, University of Tennessee (THE CONVERSATION) For the Laudick family of Greensburg, Indiana, life forever changed on Aug. 5, 2013. That was the day 4-year-old Leah Laudick told her mom, Shelly, that she had a bad headache. Two days later, Leah was hospitalized nearby with worsening headaches and a slightly elevated white blood cell count. She slept for most of the day and by Aug. 9 was largely unresponsive. That day, during her transfer to Peyton Manning Children’s Hospital in Indianapolis, Leah had her first of several seizures. Doctors were unable to identify her illness ‘” tests for diseases like meningitis, Rocky Mountain spotted fever and herpes simplex all came back negative. One day later, on Aug. 10, Leah’s brain activity stopped. That evening she passed away in the arms of her grieving parents. A few months later, the Laudicks learned from the Centers for Disease Control and Prevention that an illness called La Crosse disease, contracted from the bite of a mosquito, had caused Leah’s death. I am an entomologist at the University of Tennessee who studies how La Crosse disease spreads in the environment. I met the Laudicks ‘” they have given me permission to tell their story ‘” when Leah’s father, Andy, emailed me asking how he could help with my work. Such emails from parents of La Crosse-infected children are why I continue to study the virus. Together with other researchers at the University of Tennessee and Western Carolina University, I’m working to provide people and communities with effective solutions to preventing this illness. Through my research and community engagement activities, I am helping to increase awareness of what La Crosse virus is and how people catch it ‘” and can avoid catching it. What is La Crosse disease? La Crosse disease is the nation’s second-most prevalent mosquito-borne virus. According to the CDC, West Nile virus makes up more than 90% of annual viral infections from mosquito or tick bites, with La Crosse the next-most prevalent at about 2% of mosquito or tickborne viral infections a year ‘” or 50 to 150 cases a year. Both children and adults can be infected with La Crosse virus. La Crosse was first identified in the U.S. in 1960, and historically, most cases have occurred in Upper Midwest and Mid-Atlantic states. Leah’s case was the only one reported in Indiana in 2013. The majority now occur in the southern Appalachia region, which stretches from northern Alabama and Georgia, across eastern Tennessee and western North Carolina, and north to parts of Kentucky, Virginia and West Virginia. We still do not know why this is the case, but there are many hypotheses centered around climate, land use and invasive mosquito species. How do people catch La Crosse? La Crosse virus is carried and transmitted primarily by the eastern tree-hole mosquito, Aedes triseriatus, a native species found throughout most of the Eastern U.S. This mosquito’s preferred habitat is places with obvious tree holes for female mosquitoes to deposit their eggs, such as hardwood forests. However, the virus may also be transmitted, ‘” although not as well ‘” by two exotic and invasive mosquito species: the tiger mosquito, Aedes albopictus, and the bush mosquito, Aedes japonicus.