Babesiosis is an uncommon and potentially fatal illness of the red blood cells caused by ticks. It is caused by Babesia parasites, which are microscopic in size. When an infected deer tick bites you, they enter your bloodstream. Babesia microti is the kind that most commonly infects people. Babesia microti is transmitted by Ixodes scapularis ticks, often known as black-legged ticks or deer ticks. During the warm months (spring and summer), nymphs can be found in locations with forests, bushes, or grass. Because Ixodes scapularis nymphs are so tiny, infected people may not recall a tick bite. The bite-size may not be larger than a poppy seed. Receiving a contaminated blood transfusion or transmission from an infected mother to her infant during pregnancy or delivery are additional possible methods of getting infected with Babesia.