Lyme is not the only disease deer ticks can transmit. Scientists now know of four other pathogens the tick can transmit to humans. The oganisms are less prevalent that Lyme, but in some cases can make people much sicker.
Babesiosis, caused by microscopic parasites that infect red blood cells, can result in a range of symptoms, including fever, aches, chills, and in rare cases, death in the elderly or those with a weakened immune system or without a spleen. It is often treated using antimalaria-like drugs.