Tick season is back - how to avoid being bitten and what to do if you are They carry potentially fatal infections such as Lyme Disease Updated The video will auto-play soon8Cancel Play now People are being urged to be beware of blood sucking ticks as they head out to the countryside as lockdown restrictions ease. Ticks - which carry potentially fatal infections such as Lyme Disease- become more prevalent between May and September. The number of cases of Lyme Disease has increased - particularly in the south west - in recent years. Ticks are small, spider like creatures which feed on the blood of animals and humans.