Ticks that cause Lyme disease are continuing to expand their reach across Ontario. The illness is caused by tiny blacklegged ticks that lurk in tall grass and brush. They’re most prevalent in parts of eastern and southwestern Ontario. The province’s Chief Medical Health Officer Dr. Arlene King says the ticks are transported by migratory birds and could be anywhere in the province. Dr. King says that means wearing long-sleeved shirts with pants tucked into your socks, and using bug repellant with DEET.